Society for Experimental Biology - Centenary Conference - Abstract Book

ABSTRACT BOOK

SEB CENTENARY CONFERENCE 2023

EDINBURGH

4-7 JULY 2023

SEBIOLOGY.ORG

#SEBCONFERENCE

SEB CENTENARY CONFERENCE

1923-2023

CELEBRATING SUCCESS & SHAPING THE FUTURE

ANIMAL BIOLOGY ABSTRACTS

A1 - SENESCENCE IN A CHANGING WORLD: AGEING-RELATED MECHANISMS IN ECTOTHERMS

ORGANISED

BY: MARKO PROKIC (UNIVERSITY OF BELGRADE), PABLO BURRACO (DOÑANA BIOLOGICAL STATION), VTAMARA PETROVIC (UNIVERSITY OF BELGRADE)

A1.1 AGEING IN SOCIAL INSECTS: CASE STUDIES IN TERMITES

Wednesday 5 July 2023 09:00

Judith Korb (University of Freiburg, Germany)

judith.korb@biologie.uni-freiburg.de

Social insects like termites are emergent model organisms in ageing research. They promise to provide new insights for at least two reasons. First, the reproductive individuals (queens and in termites also kings) of a colony can live for more than 20 years, which are extraordinary lifespans for insects. Second, within the same colonies workers occur that live a few months only, although they share the same genetic background with the queen and king, which are their parents. These features offer the opportunity to investigate the mechanisms of lifespan variation in a phylogenetically controlled context.

I will summarize our current understanding of the mechanisms underlying ageing variation in termites. I will present experimental data in which we studied the effect of diet and temperature on ageing of queens and workers. I will show how important molecular pathways are affected that have been associated with ageing in animals in general. Overall, our data illustrate how a social life can mitigate senescence and buffer reproductives against adverse environmental conditions, often at costs to workers.

A1.2 AGE-RELATED MODULATION OF THE ENERGETIC METABOLISM CAPACITY IN THE HONEYBEEAPIS MELLIFERA

Wednesday 5 July 2023 09:30

Hichem A. Menail (Université de Moncton, Canada), Simon Cormier (Université de Moncton, Canada), Adèle Léger (Université de Moncton, Canada), Nicolas Pichaud (Université de Moncton, Canada)

eam5475@umoncton.ca

Aging comes with a timely decline of metabolic functions and integrity and the accumulation of damages that ultimately cause performance failure and the occurrence of age-related chronic diseases like cancer. Several theories have been proposed to explain this phenomenon. So far,

none can fully grasp aging complexity and designates its ins and outs. For that reason, in this study, we assessed the age-related modulation of the so far overlooked metabolic flexibility of the energetic metabolism which is at the core of most aging theories. Our purpose is to expand our understanding of the causes and underpinning mechanisms of aging to overcome the challenge of delaying and keep in check age-related diseases. Therefore, we used the honeybee, a prime model to study aging to assess the mitochondrial respiration and the activities of key enzymes of the energetic metabolism at four ages; 3, 8, 15 and 25 days old which represent about 90% of bees’ lifespan in the laboratory. Our results show that mitochondrial respiration increased significantly with age especially at the level of complex I of the electron transport system (ETS) and that succinate and glycerol-3-phosphate contributions to respiration differ over time. Furthermore, we observed that almost all enzymatic activities from glycolysis, tricarboxylic acid cycle and ETS increased except for lactate dehydrogenase and cytochrome c oxidase. Overall, we did not detect any signs of energetic senescence but we observed a modulation in the mitochondrial flexibility that maybe linked to lifespan of worker honeybees.

A1.3 THE EVOLUTION OF LONGEVITY IN HELICONIUS BUTTERFLIES

Wednesday 5 July 2023 09:45

Jessica R Foley (University of Bristol, United Kingdom), Stephen H Montgomery (University of Bristol, United Kingdom)

jessica.foley@bristol.ac.uk

The diversity of lifespans throughout the animal kingdom has long been a subject of interest for evolutionary biologists. With maximum longevities ranging from a single day in adult mayflies up to several centuries in the ocean quahog, the question remains: how have some organisms evolved such long lives? The high conservation of mechanisms of senescence across diverse taxa also means that studies of particularly long-lived lineages may lead to insights with relevance for human ageing.

The remarkable lifespans of the Heliconius butterfly genus, stretching up to 6 months in the wild, rank among the longest recorded in butterflies. Crucially, this lifespan extension has occurred relatively recently in evolutionary time, with recorded lifespans of only 1-2 months for their nearest relatives in the Heliconiini tribe. This longevity has been linked to the evolution of a unique pollen-feeding behaviour in Heliconius, which co-occurs with a suite of other behavioural and physiological traits that are absent in other non-pollen-feeding

Heliconiini. Leveraging this neat comparative framework between the longer-lived, pollen-feeding Heliconius, and their shorter-lived relatives, we conducted a series of long-term behavioural experiments across the lifespan of Heliconius hecale and the shorter-lived Dryas iulia, under both pollen-fed and pollen-deprived treatments, in order to study the ramifications of this pollen-feeding behaviour and associated traits on senescence in this genus. Our data provide insights into the link between lifespan and senescence, and bring us closer to disentangling the mechanisms underlying the evolution of extended longevity.

A1.4 ENVIRONMENTAL DRIVERS OF AGEING IN A TERRESTRIAL ECTOTHERM

Wednesday 5 July 2023 10:00

Luisa J Fitzpatrick (University of Tasmania, Australia), Geoff M While (University of Tasmania, Australia), Erik Wapstra (University of Tasmania, Australia)

luisa.fitzpatrick@utas.edu.au

Senescence is a universal phenomenon characterized by a decline in fertility and an increase in mortality with age. While the pace and shape of senescence vary widely among ectotherms, the processes underlying these patterns remain unclear. In particular, the relationships between reproductive and actuarial senescence in ectotherms are poorly understood. In this study, we investigated demographic senescence patterns in the viviparous spotted snow skink, a terrestrial ectothermic vertebrate with a moderate lifespan. Twenty-two years of longitudinal data on two populations with varying life histories were used to examine how mortality and reproduction changes with age and to identify the factors driving the shape and pace of senescence. We found strong and early positive actuarial senescence as well as negligible reproductive senescence, although some traits showed evidence of weak negative reproductive senescence. These patterns of senescence were similar across the two populations, despite their different life histories. Our findings suggest that extrinsic environment may not be a strong predictor of ageing rates in this ectotherm. Overall, our study provides novel insights into senescence in ectotherms and highlights the need for continued research to understand the factors driving patterns of senescence, which will be critical for predicting their population dynamics and responses to environmental change.

A1.5 THE TELOMERE ENDOTHERM

Wednesday 5 July 2023 11:00

history tradeoffs. However, this is clearly not the case with some, in particular ectotherms, showing species-specific somatic telomerase activity, with strong effects on telomere length and attrition. Thus, we would expect that, for example, the strong, non-linear telomere attrition characteristic through endotherm life appears quite different in ectotherms. Our work on Swedish sand lizards (Lacerta agilis) confirm such effects, with an increase in telomere length through life and with an increase in telomere length variability in older compared to hatchling sand lizards. This suggests that processes modifying net telomere change are linked to individual-specific cost-benefit tactics. In the Australian painted dragon lizards (Ctenophorus pictus), we show that such patterns can be linked to colour morphs with different reproductive tactics and energetic expenditure. These patterns will be used as a base for discussing ectotherm telomere and life history biology and what lessons can be learnt from expanding our telomere model systems to include more ectothermic taxa.

A1.6 REPRODUCTIVE SENESCENCE IN THE WILD. DOES IT HAPPEN IN ECTOTHERMS?

Wednesday 5 July 2023 11:30

Dustin J Marshall (Monash University, Australia)

Dustin.Marshall@monash.edu

The prevalence and nature of reproductive senescence (a decline in reproductive output with increasing age) remains hotly debated with conflicting theoretical predictions. Hampering this debate is a lack of field data on ectotherms, most data to date comes from endothermic birds and mammals, which have different paces of life relative to ectotherms. Here I present data on the relationship between age and reproductive output for ~1000 species in the field. I show that reproductive dissenescence is the rule in wild populations though tremendoud variability exists. I will discuss the implications of these findings for the management of wild populations as well as theories of aging.

A1.7 LIVING ON THE EDGE: AGEING IN A SHORT-LIVED FISH FROM TEMPORARY POOLS

Wednesday 5 July 2023 12:00

Martin Reichard (Czech Academy of Sciences, Czech Republic)

Treichard@ivb.cz

mats.olsson@bioenv.gu.se

Current knowledge about telomere biology relies to a very high degree on results from research on endotherms; two recent meta analyses captures this phenomenon with 88% of species being endotherms in one, and 91 % in the other, only the remaining species being ectotherms. This taxonomic ‘chauvinism’ would not be a problem if most organisms showed the same representation of mechanisms that regulate the dynamics of telomere length and attrition and how telomere biology may affect other traits in biology, such as life

African annual killifishes of the genus Nothobranchius inhabit ephemeral savanna pools. They hatch when their habitat is inundated, grow rapidly and naturally die within few months. Killifish populations survive annual dry period as inactive diapausing embryos. In the laboratory, killifish lifespan remains short and, within few months, it recapitulates all stages of typical vertebrate lifespan. Given their relatively easy laboratory culture, they have become vertebrate model of ageing which integrates insights from evolutionary, functional and biomedical studies. I will summarize insights from research on natural and laboratory populations dealing with life history evolution and ageing. In particular, I will address (1) the role of environment in the evolution of aging, (2) sex differences in ageing, including the

HEGEMONY: LESSONS FROM ECTOTHERMS

Mats Olsson (Department of Biological and Environmental Biology University of Gothenburg, Sweden)

role of telomeres and (3) reproductive senescence. I will stress that knowledge on natural biology of the species, and the evolutionary adaptations to their habitats, are key to comprehend the outcomes of many laboratory studies.

A1.8 ON THE INTERPLAY BETWEEN REGENERATION AND AGEING: INSIGHTS FROM THE SALAMANDER

Wednesday 5 July 2023

15:00

Max H Yun (CRTD-Center for Regenerative Therapies Dresden MPI - Molecular Cell Biology and Genetics, Germany)

maximina.yun@tu-dresden.de

Extensive regeneration of the body plan is found in a few exceptional vertebrates, including salamanders such as the axolotl (Ambystoma mexicanum) and the Spanish ribbed newt (Pleurodeles waltl). In these organisms, regeneration of complex structures relies on the modulation of cellular plasticity for the generation of regenerative progenitors, which often arise from dedifferentiation or transdifferentiation of mature adult cells instead of stem cells. Further to this, salamanders display additional noteworthy traits, namely extraordinary longevity, indefinite regenerative potential, and lack of traditional signs of age-related decay or ‘negligible senescence’. As such, they constitute valuable models for addressing the nature of organismal senescence and the interplay between regeneration and ageing.

Here, I will present our lab’s efforts towards understanding how salamanders regulate key hallmarks of ageing through regeneration and lifespan, and discuss the potential of salamander models to illuminate the nature of complex regeneration and the basis of negligible senescence.

A1.9 THE IMPACT OF ANTHROPOGENIC POLLUTION ACROSS MAJOR LIFE TRANSITIONS: A META-ANALYSIS OF OXIDATIVE STRESS IN AMPHIBIANS

Wednesday 5 July 2023

15:30

Colette Martin (University of Glasgow, United Kingdom), Pablo Capilla-Lasheras (University of Glasgow, United Kingdom), Pat Monaghan (University of Glasgow, United Kingdom), Pablo Burraco (Estación Biológica de Doñana, United Kingdom)

coletteannemartin@hotmail.co.uk

Pollution is a significant contributor to the global decline of wildlife. In particular, anthropogenic chemical pollutants are driving many amphibian populations to the brink of extinction. They are expected to impact amphibians' antioxidant machinery, negatively affecting individual health and performance. The extent to which pollutants affect amphibians, and whether this is developmental-stage dependent, remain poorly understood. We conducted a meta-analysis of 81 studies (2007 estimates) published between 1998 and 2021 to evaluate the impact of pollutants on the oxidative stress machinery of amphibians, with a focus on pre-and post-metamorphic stages. We investigated whether oxidative responses are influenced by tissue

type, climate, and life mode. Our meta-analysis revealed that the effect of pollutants on the antioxidant response varied across life stages. In tadpoles, pollutant exposure increased the antioxidant response and did not affect lipid peroxidation, a marker of oxidative damage. In adults, the antioxidant response remained unaltered, but the lipid peroxidation levels experienced a huge increase in response to pollutants. We also found that pollutants increased the antioxidant response in species with aquatic life modes and from tropical regions. The effect of pollutants on the antioxidant response was similar across tissue types. Our findings suggest that amphibians have evolved a strong antioxidant response to pollutants during the larval stage, whereas this antioxidant capacity seems to be canalised in post-metamorphic stages. Additionally, the impact of pollutants on oxidative stress is influenced by other factors including climate and life mode. These findings have important implications for conservation efforts to protect amphibians from pollution.

Wednesday 5 July 2023 15:45

Ana Kijanović (Institute for Biological Research

“Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Tanja Vukov (Institute for Biological Research

“Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Marko Mirč (Institute for Biological Research

“Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Aleksandar Mitrović (Institute for Application of Nuclear Energy, Serbia), Marko Prokić (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Tamara Petrović (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Tijana Radovanović (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Branka Gavrilović (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Svetlana Despotović (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Jelena Gavrić (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia), Nataša Tomašević Kolarov (Institute for Biological Research “Siniša Stanković” – National Institute of Republic of Serbia, Serbia)

ana.kijanovic@ibiss.bg.ac.rs

Amphibian species that inhabit temporary ponds for reproduction maximize larval growth under favorable conditions and accelerate their development to undergo rapid metamorphosis under stressful conditions such as pond drying. Corticosterone controls development, metabolism, and growth, and has an invaluable role in anuran metamorphosis under stress conditions. In this study, we evaluated whether the whole-body corticosterone (CORT) level is related to drying conditions in species that cannot accelerate the developmental rate in response to pond drying. Specifically, we investigated the effects of different water levels in combination with exogenous CORT and corticosteroid synthesis inhibitor metyrapone (treatments: high water level, high water level with exogenous CORT, low water level,

A1.10 POND DRYING CONDITIONS DO NOT ALTER WHOLE-BODY CORTICOSTERONE CONTENT AND METAMORPHIC TIME OF YELLOWBELLIED TOAD (BOMBINA VARIEGATA) METAMORPHS

low water level with metyrapone) on the whole-body corticosterone (at prometamorphosis and metamorphic climax), life history and morphological traits at the metamorphic climax. We found that these conditions did not alter the whole-body content of CORT and the developmental rate in treatments, although low water levels and exogenous CORT in high water level negatively affected other life history traits and tail shape. Individuals from a high water level with exogenous CORT had the smallest body size and mass and changed tail shape at metamorphosis, while changes in life history traits did not affect the tail shape in the other treatments. Our findings indicate that the absence of developmental response (i.e. canalized development) in the timing of metamorphosis of B. variegata may be explained by a modification of endocrine regulation but further studies that would include closely related species are required.

A1 EVOLUTIONARY ECOLOGY IN EXTREME ENVIRONMENTS

ORGANISED BY: DR.

GERMÁN ORIZAOLA (UNIVERSITY OF OVIEDO), DR. PABLO BURRACO (DOÑANA BIOLOGICAL STATION)

A2.1 HIGH ALTITUDE IS FOR THE BIRDS

Tuesday 4th July 2023 09:00

Lucy A Hawkes (University of Exeter, United Kingdom)

l.hawkes@exeter.ac.uk

High altitudes pose several challenges across biological systems, including hypoxia, hypobaria, dehydration and cold. Many highly adapted species from a range of taxa have met these challenges by supressing metabolic demands, and in doing so have thrived in austere environments. By contrast, birds have evolved a cardiorespiratory system that allows them to exploit high metabolic rates, up to an order of magnitude above resting, even in very high altitude environments. This talk will describe the unique avian pulmonary system and explain why it (along with other physiological adaptations) allows all bird species to thrive in hypobaric and /or hypoxic environments relative to mammals. I will also detail that several species in particular appear to have adaptations that make them stand out even further as champion physiological performers. Lastly, the ecological ramifications of this ability will be discussed.

A2.2 INTERGENERATIONAL IMPACT OF FLUCTUATING HYPOXIA ON TWO POPULATIONS OF GASTEROSTEUS ACULEATUS

Tuesday 4th July 2023 09:30

Ludovic Toisoul (University of Turku, Finland),

Alycia Valvandrin (University of Turku, Finland),

Clara Corvé (University of Turku, Finland), Elina Chiesa (University of Turku, Finland), Luisa Bermejo Albacete (University of Turku, Finland), Katja Anttila (University of Turku, Finland), Amélie Crespel (University of Turku, Finland)

ludovic.toisoul@utu.fi

One of the biggest climate change threats to aquatic ecosystems is the increased occurrence of hypoxia (i.e. decrease of dissolved oxygen level in water) events. Freshwater ponds and lakes are particularly vulnerable ecosystems as hypoxic events cannot be avoided and therefore organisms can experience chronic hypoxia effects. While transgenerational plasticity and parental exposure could influence an individual response to environmental stressors and promote phenotypic evolution, there is still little knowledge on the multigenerational

effect of hypoxia on fish. To investigate this, two wild populations of Gasterosteus aculeatus were collected from two freshwater streams in Hamburg (Germany), one exposed to hypoxia and one exposed to normoxia. The F1 and F2 offspring generations of the wild fish were created within each population and exposed to both normoxia (100% dissolved oxygen, DO), or daily fluctuating hypoxia (30% DO at night and 100% DO during the day) mimicking the pattern of oxygen fluctuation in their wild environment. This design allowed us to disentangle acclimation to intergenerational plasticity and how matching parental environment affects the offspring's fitness, as well as possible adaptation between the two populations. We measured the fish swimming performance, hypoxia tolerance, and social behavior. The results showed that direct exposure to hypoxia (acclimation) increased hypoxia tolerance but decreased sociability while parental exposure to hypoxia improved swimming performance. This study bridges the current gap on how fish populations can respond to hypoxia on different time scales, from plasticity to evolution, and highlights the possibility for species resilience to changing environments.

A2.3 LONGER RECOVERY TIMES AFTER

AT CLASSIC HYPOXIA RELATED BIOMARKERS.

Tuesday 4th July 2023 09:45

Gudrun De Boeck (University of Antwerp, Belgium), Chris M Wood (University of British Columbia, Canada)

gudrun.deboeck@uantwerpen.be

Pacific spiny dogfish Squalus suckleyi showed critical oxygen levels (Pcrit) at 18% saturation. Regulation of oxygen consumption rates (MO2) showed large variation among individual dogfish, and many behaved as conformers with declining MO2 as hypoxia progressed. This corresponds with arterial blood Po2 levels, which decreased linearly with decreasing water oxygen saturation. In closed respirometry, arterial pHa decreased and blood Paco2 and bicarbonate [HCO3-] increased. This was not seen in open systems with hypoxia induced by N2 bubbling where Paco2 decreased and pHa increased slightly despite increasing lactate levels. In both set-ups, ventilation frequency increased with decreasing Po2 with a maximum attained sooner in the closed system (40% saturation compared to 20%). Qualitative 1 H-NMR spectroscopy of polar extracts of hypoxic dogfish (11-12% saturation for 2-6h) showed substantial changes in white muscle and gill metabolites. Hypoxia resulted in an up-regulation of anaerobic glycolysis (increased lactate) in all tissues except brain. Overall, brain metabolites were not affected, while liver tissue only showed increased lactate. Increased relianceon ketone bodies as oxidative substrates was shown by decreased concentrations

A HYPOXIC EVENT IN SHARK MIGHT BE MISSED WHEN LOOKING

of acetoacetate in white muscle. Additionally, reductions in glutamate, glutamine and amino acids were observed. Miscellaneous metabolites were affected: trimethylamine oxide increased in muscle and gill, oxypurinol levels decreased in muscle, and myo-inositol did the same in gills. After 6 hours of normoxic recovery, most of these changes persisted and only lactate had returned to normal in liver and muscle (but not gill), indicating that longer recovery periods are needed after an hypoxic event (NSERC Discovery).

A2.4 GAS EXCHANGE OF FOUR SMALLBODIED REPTILES, UNDER HIGH AND EXTREME LOW HUMIDITY CONDITIONS

Tuesday 4th July 2023 10:00

Shahar Dubiner (Tel Aviv University, Israel), Shai Meiri (Tel Aviv University, Israel), Eran Levin (Tel Aviv University, Israel)

dubiner@mail.tau.ac.il

Reptile skins are dry and glandless, and therefore reptiles have low evaporative water loss (EWL) than other vertebrates. However, extremely small-bodied reptiles have high respiration rates and surface-area-to-volume ratios, making them more vulnerable to water loss and favouring physiological adaptations to extreme aridity. We measured the resting metabolic rates (RMR) and EWL at 25°C, of 6 resting individuals of four small reptile species: a gecko (Tropiocolotes yomtovi, mean mass 0.3g), a skink (Ablepharus ruepellii, 0.5g), a blind snake (Xerotyphlops syriacus, 1.9g), and a colubrid snake (Eirenis rothii, 2.7g). Individuals were measured twice at 70% relative humidity (RH), and twice at near 0% RH. Restfulness was confirmed by IR camera. The snakes (that are restricted to humid microhabitats in nature) exhibited significantly higher RMR in the dry conditions, whereasT. yomtovi(an arid desert species) had lower RMR under dry conditions. EWL increased in the dry conditions – especially in the mesic-adapted species.At 70% RH, however, was uniformly low for all species. Lower RMR in dry air, with limited increase in EWL, may represent a solution to conserve water by the desert gecko by reducing respiration rates. The increased RMR of the other species may be due to stress when exposed to the unnaturally dry conditions. The effect of air humidity on gas exchange of different species is crucial for other studies to consider when drawing conclusions from respirometric measurements (which are nearly always conducted in dry air).

A2.5 IN THE HEAT OF THE NIGHT: HYPOXIA SHAPES THE PHYSIOLOGY AND ECOLOGY OF CORAL REEFS.

Tuesday 4th July 2023 10:15

Andrea Campos-Candela (Department of Biological Sciences

University of Bergen Bergen, Norway), Rachael Morgan (Department of Biological Sciences

University of Bergen Bergen, Norway), Rebecca E. Holt (Centre for Ecological and Evolutionary Synthesis (CEES) University of Oslo, Norway), Suzanne Mills (PSL Université Paris : EPHE-UPVD-CNRS USR 3278 CRIOBE and Laboratoire d’Excellence CORAIL, France), Adriana Humanes (Newcastle University Newcastle upon Tyne, United Kingdom),Anna H. Andreassen (Norwegian University of Science and Technology (NTNU) Trondheim, Norway), Ricardo Beldade (Estación Costera de Investigaciones Marinas Pontificia Universidad Católica de Chile Santiago, Chile), Clark Timothy (School of Life and Environmental Sciences Deakin University Geelong, Australia), Fredrik Jutfelt (Norwegian University of Science and Technology (NTNU) Trondheim, Norway), Christian Jørgensen (Department of Biological Sciences University of Bergen Bergen, Norway)

Andrea.Campos-Candela@uib.no

On coral reefs, oxygen supersaturation during the day and particularly hypoxic conditions during the night may be critical in explaining life history strategies for reef inhabitants. These extreme oxygen conditions have been mostly overlooked when investigating the evolutionary ecology in corals reefs. Our main hypothesis is that late-night hypoxia on tropical coral reefs is a daily bottleneck that structures physiology, life history, behaviour, and biodiversity in corals and reef-dwelling fishes. Within the lagoon in Moorea, French Polynesia, we have explored this hypothesis by measuring the daily oxygen fluctuations, filming the behaviour of damselfish at night, and measuring how oxygen affects the fishes’ metabolic rates under laboratory conditions. How and when does hypoxia happen on coral reefs? What are the ensuing trade-offs and how does hypoxia affect predator-prey interactions? Here we present our field and laboratory results and discuss the insights we have gained. (*Note: both first authors will present this talk together).

A2.6 STUDYING HOT-SPRING FISH TO UNDERSTAND PHYSIOLOGICAL ADAPTATION TO HIGH TEMPERATURE

Tuesday 4th July 2023 13:30

Natalie Pilakouta (University of Aberdeen, United Kingdom)

natalie.pilakouta@abdn.ac.uk

Climate change poses a significant threat to biodiversity, so there is a pressing need to understand the capacity of populations to respond and adapt to increasing temperatures. Ectotherms are particularly vulnerable to changes in ambient temperature, because this directly influences their body temperature. Ectotherms are therefore expected to adapt to climate change through plastic and/or evolutionary changes in a wide range of physiological traits. To better understand these plastic and evolutionary responses to temperature, we are using a novel approach

of comparing populations of threespine sticklebacks (Gasterosteus aculeatus) found in geothermally warmed waters (‘hot springs’) and adjacent ambient-temperature lakes in Iceland. This unique natural experiment provides repeated and independent examples of populations experiencing contrasting thermal environments for many generations over a small geographic scale, thereby avoiding the confounding factors associated with latitudinal or elevational comparisons. We are taking advantage of this study system to study (i) plastic responses by looking at within-population variation at different temperatures and (ii) evolutionary responses by comparing warm- and cold-adapted populations at a common temperature. Some of the physiological traits we have examined include metabolic rate, fat storage, insulin resistance, and starvation resistance. We have found strong divergence in these traits between warm- and cold-adapted fish, providing valuable insights into how fishes and other ectotherms may adapt in a warming world.

A2.7 ARIDITY PREDICTS WATER LOSS AND MORPHOLOGY IN COMMON MOLE-RAT

(CRYPTOMYS HOTTENTOTUS HOTTENTOTUS) POPULATIONS FOUND ALONG AN ENVIRONMENTAL GRADIENT

Tuesday 4th July 2023 14:00

Hana N. Merchant (Royal Holloway University of London, United Kingdom), Daniel W. Hart (University of Pretoria, South Africa), Nigel C. Bennett (University of Pretoria, South Africa), Chris G. Faulkes (Queen Mary University of London, United Kingdom), Steven J. Portugal (Royal Holloway University of London, United Kingdom)

phba013@live.rhul.ac.uk

Mole-rats occupy a wide range of habitats, and despite being subterranean, are impacted by both local and broad-scale environmental conditions that occur above ground. Common mole-rats present an ideal model mammalian species for the study of energetics and morphology in different populations of the same species, found along an aridity gradient. Thus, it is possible to determine the degree of plasticity within a single species with respect to climatic extremes and is particularly pertinent for species such as mole-rats, which are not migratory. Using respirometry and skeletal measurements we assessed the energetics and morphology of 60 wild non-breeding individuals across five distinct populations. The results from this study demonstrate that metabolic rate and evaporative heat loss did not differ significantly between the populations. However, individuals from different populations employed distinct behavioural cooling techniques at higher temperatures. This indicates they have developed alternative strategies to deal with extreme temperatures, and that metabolic rate may not be a determining factor in temperature adaptation. The plasticity of metabolic rate either has its limits within this species or is not the determining factor in dealing with high temperatures. Morphology, however, did differ between populations, as individuals in arid regions had shorter legs and shorter incisor lengths. This indicates that these populations show unique adaptations in response to aridity such as the different food sources found in different biomes, and soil composition, as mole-rats dig through soil with their teeth. Such findings have important implications for the conservation of subterranean species in a changing climate.

A2.8 INVESTIGATING THE METABOLOMIC PROFILES AND ABILITY FOR METABOLIC REPROGRAMMING UNDER ACUTE THERMAL STRESS IN MARINE POLAR GIANTS

Tuesday 4th July 2023 14:15

Piero Calosi (University of Quebec in Rimouski, Canada), Ignacio Garrido (Laval University, Canada), Fanny Vermandele (University of Quebec at Rimouski, Canada), Lauric Feugere (University of Quebec at Rimouski, Canada), Luis Miguel Pardo (Universidad Austral de Chile, Chile)

piero_calosi@uqar.ca

In marine polar environments giant species can be found across a considerable number of taxonomic groups: including for example, amphipods, isopods, pycnogonids, nemerteans, ophiuroids and tunicates. Gigantism has historically been proposed to have evolved because of cold-driven low metabolic rates and high oxygen availability at the poles, promoting slow growth, high longevity and ultimately enabling the evolution of larger body sizes. More recently, larger bodies were proposed to have evolved to overcome the greater viscosity of cold waters and limit the risk of oxygen poisoning. Research on marine giant species has to date primarily focussed on describing the relationship between oxygen availability, body mass and metabolic rates. However, we know virtually nothing on other aspects of the physiology of polar giants, such as for example their cellular physiology. This is particularly important to help shedding light on the evolution of giants’ physiological systems, and the impact that ongoing environmental changes could have on them. To help overcoming this knowledge gap, we characterized metabolomic profiles, and the ability for metabolomic reprogramming following a short-term exposure to an acute thermal stress, of four Antarctic giants and five of theirs “regular-size” relatives. Target species belonged to three distinctive taxonomic groups: amphipods, pycnogonids and ophiuroids. We hypothesize that giants possess a lower energy status, and a lesser ability for cellular metabolic reprogramming when exposed to elevated temperatures. We discuss our findings within the context of the physiological evolution of polar marine giants, and their vulnerability to ongoing global changes, compared to regular-sized species.

A2.9 CORRELATED RESPONSE OF THERMAL PERFORMANCE TRAITS TO ARTIFICIAL SELECTION FOR CTMAX

Tuesday 4th July 2023 14:30

Anna H. Andreassen (Norwegian University of Science and Technology, Norway), Jeff C. Clements (Fisheries and Oceans Canada Gulf Region, Canada), Rachael Morgan (University of Bergen, Norway), Eirik R. Åsheim (University of Helsinki, Finland), Davide Spatafora (University of Palermo, Italy), Christophe Pelabon (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway)

anna.h.andreassen@ntnu.no

Selection pressure on aquatic ectotherms due to heat exposure is increasing with the increasing frequency of extreme heating events. The evolutionary response to selection for increased thermal tolerance may affect many traits in concert. However, the connections between increased thermal tolerance and the performance of other physiological traits are still poorly known. We tested the response of a range of traits to artificial selection on upper thermal tolerance limits (CTmax ) in zebrafish (Danio rerio). CTmax evolved in the predicted directions over seven generations of artificial selection to increase or decrease upper thermal tolerance. We additionally quantified a range of physiological traits (e.g., fecundity, growth rate, aerobic scope, acute Q10 response in metabolic rates, maximum swimming speed, and thermal tolerance scope) in the selected lines. Identifying which performance traits were indirectly selected for or against expands our understanding of the ecological consequences of evolution of upper thermal tolerance. The results contradict some physiological mechanisms hypothesised to limit thermal tolerance and have important implications for future studies of upper thermal tolerance limits.

A2.10 DO FREQUENT HEATWAVES DAMAGE MALE REPRODUCTIVE TISSUE?

Tuesday 4th July 2023 14:45

Abhishek Meena (University of Zurich, Switzerland), Alessio De Nardo (University of Zurich, Switzerland),

Komal Maggu (University of Zurich, Switzerland),

Sonja Sbilordo (University of Zurich, Switzerland),

Jeannine Roy (University of Zurich, Switzerland), Rhonda Snook (University of Zurich, Switzerland), Stefan Lüpold (University of Zurich, Switzerland)

abhishek.meena@ieu.uzh.ch

Extreme weather events are a threat to biodiversity. Studies on the consequences of climate change on biodiversity tend to focus on where and how species can survive. However, the persistence of a species depends not only on survival but also on reproduction. Fertility is often more sensitive to heat stress than survival, as damage to gametes can occur at sublethal temperatures. Thermal sensitivity usually varies between life stages. Most previous studies focus on one stage and/or sex at one point just after the heat stress or without including genetic variation. However, there is still a lack of understanding of the fitness consequences of heatwaves in multiple life stages and the underlying genetic variation. Therefore, to address these issues, we investigated the following questions: (i) how heatwaves impact male reproduction during the developmental and/or the adult stage in Drosophila melanogaster, (ii) whether males’ reproductive capacity can recover from heatwaves and what extent. We found a significant interaction between larval & adult heat stress on male reproductive tissue, resulting in a decline in fertility, and fecundity even after a recovery period. Extreme heat waves seem to have a damaging effect on male reproductive function. This study illustrates the severe impact of heat stress on male reproductive traits. It could speed up population declines through fertility loss, highlighting the need to include effects on reproduction in studies of biodiversity loss. This study is especially important for insects, given their fast global decline and direct dependence on the temperature of their environment.

A2.11 LIVING IN VINEYARDS: IMPACTS OF EXTREME CONTAMINATION ON ORGANISMAL SYSTEMS IN FARMLAND BIRDS

Tuesday 4th July 2023 15:30

Frederic Angelier (Centre d'Etudes Biologiques de Chizé, France), Pauline Bellot (Centre d'Etudes Biologiques de Chizé, France), Bertille Mohring (Centre d'Etudes Biologiques de Chizé, France), Francois Brischoux (Centre d'Etudes Biologiques de Chizé, France)

frederic.angelier@cebc.cnrs.fr

Recent studies have suggested that most if not all agroecosystems are contaminated, sometimes to extremely high levels, by pesticides. There has been growing concerns regarding these pesticides because they can contaminate wild vertebrates and affect non-target physiological mechanisms in laboratory models. However, it remains unclear whether and how wild vertebrates can cope with the release of these pesticides in the environment, notably when they are massively used. Indeed, we currently lack not only environmental data on the degree of contamination of farmland vertebrates, but also field and experimental data regarding the effect of sublethal doses of pesticides on organismal traits. Here, we focused on fungicides, and more specifically triazoles, which are used worldwide in agroecosystems. We combined field and experimental approaches to better understand the risk that these fungicides may represent for farmland birds. Firstly, we sampled birds from agroecosystems, and we found a ubiquitous contamination by triazoles in several species. Importantly, this contamination was extremely high in vineyards. Secondly, we examined several morphological and physiological traits and we found that birds showed an altered phenotype in vineyards relative to other agroecosystems. Finally, we experimentally exposed captive birds to realistic doses of fungicides and we demonstrated a detrimental impact of triazoles on reproduction, development, and post-fledging survival. Altogether, these results suggest that triazole fungicides may represent a threat to farmland birds, especially in vineyards. Based on these findings, futures studies are now needed to explore whether adaptive organismal processes occur to limit the detrimental effects of fungicides on farmland birds.

A2.12 CAN INVASION STRESS MITIGATE CLIMATE STRESS? THE PHYSIOLOGICAL PERFORMANCE OF MUD-DWELLING INVERTEBRATES IN A RESTORED TIDAL WETLAND

Tuesday 4th July 2023 16:00

Richelle L Tanner (Chapman University, United States), Lorna E Haworth (University of California at Davis, United States), Sarah Nancollas (University of California at Davis, United States), Anne E Todgham (University of California at Davis, United States)

rtanner@chapman.edu

Organisms in coastal brackish ecosystems face not only highly variable environmental conditions, but also the effects imposed by climate change that increase the intensity and stochasticity of these

environmental conditions. However, invertebrates living amongst the vegetation of Suisun Marsh in the California Delta may have an advantage. While native plant canopies allow light and heat penetrate to the understory, the canopies of the introduced Phragmites australis reed block out sunlight and heat for organisms living below. What results is a thermal profile that is both cooler on average and less variable throughout the day. We set out to understand the physiological performance of mud-dwelling invertebrates in this context: can invasion stress mitigate climate stress? We raised field-collected amphipods in the laboratory under simulated “native canopy” and “Phragmites canopy” temperature/light conditions based on data from our field environmental loggers. We assessed survival, size, glycogen, and protein content every two weeks from our lab population of amphipods. We found that amphipods raised under the Phragmites conditions had better survival, more offspring, and greater stores of glycogen and protein, which is important considering their utility as food resources for fishes. We support this with field data showing the use of Phragmites canopies by amphipods during low tide. Understanding the potential benefits of Phragmites as climate stress refugia can inform management decisions around its mitigation in future restoration.

A2.13 LIFE IN THE MARGINS: THE EFFECT OF TIDAL HEIGHT AND TIDAL CYCLE ON PATELLA VULGATA PROTEIN SYNTHESIS RATES

Tuesday 4th July 2023 16:15

Ignacio A Cienfuegos (Plymouth University, United Kingdom), Benjamin J Ciotti (Plymouth University, United Kingdom), Richard A Billington (Plymouth University, United Kingdom), Keiron P P Fraser (Plymouth University, United Kingdom) ignacio.alvarez-cienfuegos@plymouth.ac.uk

Biological processes in intertidal species follow tidal rhythms that enhance the organism survival and fitness. Patella vulgata is an intertidal limpet present in North-Eastern Atlantic rocky shores from high to low tide levels. No studies to date have measured the tidal effects on fractional protein synthesis rates in any species. In P. vulgata, respiration and heartbeat analyses suggest aerobic metabolism is maintained during emersion. A positive gradient from high to low shore has also been reported in this species growth rates. Here, we measured for the first time in any intertidal organism protein synthesis rates and RNA to protein ratios over a full tidal cycle in the limpet P. vulgata at three different shore heights. Protein synthesis rates increased during aerial emersion in mid and low shore limpets and no differences were found between submerged and emersed individuals from the high shore. Mass-scaled protein synthesis rates were significantly higher in low shore animals compared to the other shore heights and temperature was positively correlated to protein synthesis rates. RNA to protein ratios and RNA translational efficiency remained unchanged over the tidal cycle at all shore heights. This study demonstrates that P. vulgata maintains protein synthesis during emersion and confirms it has adapted to survive well out of the water. Within the marine ecosystem, intertidal species will be especially impacted by a warming climate, so further studies are needed to better understand protein metabolism response to heat stress in P. vulgata and other intertidal species.

A2.14 THE IMPACTS OF EXTREME OSMOTIC STRESS ON THE TARDIGRADE HYPSIBIUS EXEMPLARI

Tuesday 4th July 2023 16:30

Ellis C Moloney (University of Plymouth, United Kingdom), Chiara Boschetti (University of Plymouth, United Kingdom), Jon S Ellis (University of Plymouth, United Kingdom)

ellis.moloney@plymouth.ac.uk

Tardigrades are microscopic animals famed for their ability to survive extreme conditions. By entering a state of dormancy, known as cryptobiosis, tardigrades can tolerate desiccation, freezing, high doses of radiation, and even the vacuum of space. However, the biological mechanisms underpinning stress response remain unclear. Cryptobiotic capabilities are diverse depending on stressors and across tardigrades species, suggesting a possible divergence in protective mechanisms. Therefore, the less-well-studied stressors should be incorporated in a comparative analysis to truly build a detailed picture of extreme stress response in tardigrades. This study is the first to investigate the response of H. exemplaris, a weak cryptobiont, to acute osmotic stress. Individuals were exposed to increasing concentrations of ionic and non-ionic osmolytes for 24 hours, then placed into recovery for a further 72 hours and their activity was measured. Results show that H. exemplaris has a higher tolerance to sucrose compared to NaCl across all treatments, suggesting that the ionic impacts of NaCl extend further than purely osmotic. Statistical modelling shows that there is a significant difference in recovery between each treatment for both NaCl and sucrose, but that time does not have a significant impact on the recovery rate. Response of the tardigrades to pre-conditioning will also be discussed considering previous work across metazoans.

A2.15 REARING-SITE’S VISUAL ENVIRONMENT AFFECTS LARVAL RESPONSE TO PERCEIVED RISK

Tuesday 4th July 2023 16:45

Chloe A Fouilloux (University of Jyväskylä, Finland), Jennifer L Stynoski (University of Costa Rica, Costa Rica), Carola A. M. Yovanovich (University of Sussex, United Kingdom), Bibiana Rojas (University of Veterinary Medicine Vienna, Austria)

chloe.a.fouilloux@gmail.com

Turbidity challenges the visual performance of aquatic animals. During development, environments with limited visibility may affect the finetuning of visual systems and thus the perception of, and response to, risk. Here, we use the natural diversity of ephemeral microhabitats where two poison frog species occur to investigate the importance of visual backgrounds and cues on the perception of risk. We compare how a habitat generalist and tadpole predator (Dendrobates tinctorius) versus a microhabitat specialist dependent on maternal food-provisioning (Oophaga pumilio) use vision to navigate their environment and respond to risk. Sampling tadpoles from the wild, we investigated how the photic environment of natal pools influences tadpole behaviour. We measured tadpole activity and space use in experimental arenas; first on a black and white background, followed by either black or white backgrounds where tadpoles were exposed to visual stimuli of conspecifics or potential predators. The effects of the rearing environment on D. tinctorius tadpoles were clear: tadpoles from

darker pools were less active than tadpoles from brighter pools, and did not respond to either visual stimuli, whereas tadpoles from brighter pools appear to visually discriminate between predators. For O. pumilio, tadpoles were more active on experimental backgrounds that more closely matched the luminosity of their rearing sites. Larval specialisation in response to species-specific microhabitat choice may underlie the observed responses to visual stimuli. Using extreme habitats as a model system, these results have implications for visuallyguided animals may respond to sudden environmental disturbances.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A2.16 HEART RATE REDUCTION DURING DIVING AFFECTED BY DIVE DEPTH AND DURATION IN FREE-RANGING LOGGERHEAD SEA TURTLES

Wednesday 5 July 2023 POSTER SESSION

Ayaka Saito (The University of Tokyo, Japan), Chihiro Kinoshita (Meijo Universtity, Japan), Kino Sakai (The University of Tokyo, Japan), Katsufumi Sato (The University of Tokyo, Japan), Kentaro Q Sakamoto (The University of Tokyo, Japan)

saito-ayaka97@g.ecc.u-tokyo.ac.jpk

Air-breathing vertebrates are known to exhibit the cardiac response to diving. Field studies in aquatic mammals and birds have shown that a profound heart rate reduction occurs during diving and that the intensity of reduction could reflect its diving behaviour, such as depth of dives and dive durations. However, in aquatic reptiles, the regulation of heart rate during deep and long dives has not been investigated. In this study, we attached recorders to 5 loggerhead sea turtles (Caretta caretta) and released them into the ocean to measure electrocardiogram, depth, temperature, and 3-axis acceleration. After 3 days later, the recorders were automatically detached from the turtles. The heart rate signal was detected from the electrodes placed on the surface of the plastron. We defined dive as staying at deeper than 1 m for more than 5 minutes, and surface as staying at shallower than 1 m for more than 1 minute. The mean heart rate during dives (12.6 ± 4.2 beats min–1 ) was significantly lower than the heart rate at the surface (21.8 ± 3.8 beats min–1 ). Furthermore, the minimum instantaneous heart rate during dives was negatively correlated with both the maximum depth of dives and dive durations. When the turtle dived deeper than 140m, the heart rate dropped rapidly to about 2 beats min–1 temporarily. Our results indicate that heart rate reduction during diving is a common physiological response among aquatic air-breathing vertebrates, including aquatic reptiles to deep and long dives.

A2.17 CHANGES IN HEART RATE AND THE NUMBER OF BREATHS AT THE SURFACE IN FREE-RANGING LOGGERHEAD SEA TURTLES

Wednesday 5 July 2023

POSTER SESSION

Kino Sakai (Atmosphere and Ocean Research Institute

The University of Tokyo, Japan), Ayaka Saito (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Ryota Murakami (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Tomohiro Tajima (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Kenta Kuroda (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Katsufumi Sato (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Kentaro Q Sakamoto (Atmosphere and Ocean Research Institute The University of Tokyo, Japan)

skino243@g.ecc.u-tokyo.ac.jp

Aquatic air-breathing animals repeatedly dive to take underwater prey and return to the surface to obtain oxygen. Since underwater activity is restrained by the amount of oxygen stored in the body, the balance between oxygen consumption and uptake, which is regulated by diving behaviour and cardiopulmonary function, is an important parameter for better understanding the diving strategies of aquatic air-breathing animals. However, for free-ranging sea turtles, such a balance has not been well examined. In this study, we record the electrocardiogram, depth, 3-axis acceleration, and video of five free-ranging loggerhead turtles (Caretta caretta) for 3 days with data loggers which were automatically detached. Surface duration was used as a direct proxy for the number of breaths because of their strong correlation (r = 0.92). Dive duration was significantly correlated better with the preceding surface duration (r = 0.70) than the succeeding one (r = 0.56). This is a similar behaviour strategy to diving birds and contrasts with aquatic mammals where post-dive time correlates well with dive duration. In addition, heart rate, which decreased during diving, began to increase at the start of the ascent and continued to increase at the surface. The rate of increase in heart rate during ascent (0.08 ± 0.03 beat min–1 sec–1 ) was about twice as fast as that at the surface (0.04 ± 0.02 beat min–1 sec–1 ). This anticipatory physiological response of heart rate increase may facilitate tachycardia and maximise oxygen uptake at the surface in preparation for the next dive.

A2.18 THRIVING IN THE HEAT: INVESTIGATING THE PHENOTYPIC AND PHYSIOLOGICAL RESPONSES OF SCORPIONS TO THE EXTREME ENVIRONMENT OF THE MOROCCAN SAHARA

Wednesday 5 July 2023

POSTER SESSION

Mouad MKAMEL (Mohammed VI University of Sciences and Health, Morocco)

contact@mkamelmouad.com

The Moroccan Sahara is a harsh environment characterized by high temperatures, limited water availability, and extreme aridity. Scorpions are among the most successful arthropods that inhabit this region and have developed remarkable adaptations to survive in such an extreme environment. In this study, we investigated the phenotypic and physiological responses of scorpions to the harsh conditions of the Moroccan Sahara. We collected scorpions from different locations in the region and measured their morphological traits, such as body size and coloration, as well as physiological parameters, such as metabolic rate, water loss, and thermoregulatory behavior. Our results showed that scorpions from the Moroccan Sahara exhibit unique adaptations to cope with the extreme environment. They have a smaller body size and darker coloration, which helps them to reduce heat absorption and retain water. They also have a lower metabolic rate and a more efficient water conservation system, which allows them to survive for extended periods without water. Furthermore, scorpions from this region exhibit thermoregulatory behavior, such as burrowing during the day and emerging at night, to avoid the extreme temperatures during the day. Our findings highlight the remarkable ability of scorpions to adapt to extreme environments and provide insights into the underlying mechanisms of their survival in such conditions.

A2.19 PARENTAL LARVAL DENSITY AND OVIPOSITION SUBSTRATE INFLUENCE OVIPOSITION BEHAVIOURS AND OFFSPRING PERFORMANCE

Wednesday 5 July 2023 POSTER SESSION

The Anh Than (Macquarie University, Australia), Fleur Ponton (Macquarie University, Australia), Ajay Narendra (Macquarie University, Australia), Duc Tung Nguyen (Macquarie University, Australia)

anh.than-the@hdr.mq.edu.au

Oviposition choice is a complex behaviour that has significant fitness consequences. To date, however, our understanding of how the environment interacts with oviposition decision is still limited. Our previous research showed a significant interaction between larval density and nutritional composition of rearing substrate on development and adult fitness of a polyphagous fly. Here, we explored how the larval density of parents and the nutritional composition of the oviposition substrate shape oviposition choice of femaleDrosophila melanogasterand, in turn, modulate offspring survival and reproduction. The results showed no direct interaction between the oviposition substrate composition and the parental

density on offspring development and reproduction. Females laid a higher number of eggs on the protein-biased substrate, compared to the balanced or carbohydrate-biased substrates when not given a choice, independently of the density they were reared in. However, when provided a choice between three substrates, females laid more eggs on the carbohydrate-biased one. This result is surprising considering that the nutritional composition of the oviposition substrate greatly influenced offspring performance whereby pupation and reproduction were higher when developing in the protein-biased substrate. When parents where reared at high larval density, pupal production and adult emergence was greater, but the number of deposited eggs was smaller than for parents reared at low and medium densities. These results were independent of the oviposition substrate composition. Our findings provide for the first time an insight into the effects of the oviposition substrate nutritional composition and the parental larval density on offspring performance in insects.

A2.20 PATERNALLY-TRANSMITTED EFFECTS OF POLLUTION: NEW BIOMARKERS OF HEAVY METAL EXPOSURE IN BIRDS?

Wednesday 5 July 2023 POSTER SESSION

Lisandrina Mari (University of Jyväskylä, Finland), Sara Calhim (University of Jyväskylä, Finland), Phillip Watts (University of Jyväskylä, Finland), Tapio Eeva (University of Turku, Finland), Suvi Ruuskanen (University of Jyväskylä, Finland)

lisandrina.mari@orange.fr

Among the pressures affecting terrestrial biodiversity, heavy metal pollution presents an increasingly important concern to wildlife health worldwide. Exposure to heavy metals is known to induce a variety of adverse effects on vertebrates by either directly disrupting their physiology or through food chain contamination. Pollution can further elicit molecular effects that can be passed down to the next generations. Birds are extremely valuable bioindicators of pollutant exposure, but most studies have insofar focused either on studying pollution within a single generation or investigated maternal transmission of effects to offspring. Paternal effects constitute as such an overlooked aspect of the impacts of anthropogenic pollution on birds. Our new project focuses on this knowledge gap and aims at characterizing how heavy metals affect sperm molecular traits and quality, and how these in turn affect offspring. We will develop molecular biomarkers of paternal exposure (DNA methylation and telomere shortening) in an experimental approach on a quail model where paternal pollution levels are controlled, and apply them in-situ to metal-exposed populations of wild birds with different life histories and thus, vulnerability to pollution (resident great tits and migratory flycatchers). Overall, this project will bring important insights on the role of epigenetic inheritance in the response and adaptation potential of bird populations to anthropogenic pollution.

A2.21 IMPACT OF MARINE HEATWAVES ON THE BIOLOGY OF THE MANILA CLAM RUDITAPES PHILIPPINARUM: A MULTILEVEL APPROACH

Wednesday 5 July 2023

POSTER SESSION

Luca Peruzza (University of Padova, Italy), Carmen Tucci (University of Padova, Italy), Giulia Dalla Rovere (University of Padova, Italy), Riccardo Frizzo (University of Padova, Italy), Andrea Quagliariello (University of Padova, Italy), Maria Elena Martino (University of Padova, Italy), Mattia Panin (University of Padova, Italy), Tobia Riello (University of Padova, Italy), Francesco Camerani (University of Padova, Italy), Massimo Milan (University of Padova, Italy), Morgan Smits (University of Padova, Italy), Alice Manuzzi (University of Padova, Italy), Paola Venier (University of Padova, Italy), Stefano Mammi (University of Padova, Italy), Luca Bargelloni (University of Padova, Italy)

luca.peruzza@unipd.it

Extreme events like Heatwaves (HWs) are a serious threat for marine ecosystems. One of the most threatened activities is bivalve aquaculture since bivalves are mostly farmed in coastal ecosystems where the predicted impacts of HWs will be more intense. However, our knowledge regarding such effects is still limited. To fill this gap, we used the Manila clam Ruditapes philippinarum as model species to characterise in detail clams’ responses after an HW (i.e. 30 ˚C for 30-days).

Results indicated an impairment of burying behaviour, a significant decrease in hepato-somatic index and a reduction of oocyte diameter in HW-exposed clams. At biochemical level, the activity of superoxide dismutase, catalase and glutathione peroxidase were significantly increased in HW-exposed clams. The metabolic profile of clam’s foot showed higher concentrations of Alanine and Glutamate, suggesting the activation of a metabolic pathway to produce glucose via degradation of amino acids. Transcriptomic analysis in the hepatopancreas revealed a down-regulation of genes involved in the reproductive cycle and an upregulation of pathways like “Unfolded protein response”. Finally, HWs caused a significant reduction in microbiota diversity with higher intra-variability than control clams, suggesting the onset of dysbiosis.

Overall, we highlight an important trade-off: despite clams survived the HW, energy reserves were diverted from biological processes (e.g. reproduction) to deal with oxidative stress, protein misfolding and stress. Arguably clam’s resilience is pushed to its limit by HWs and if, in the field, HWs co-occur with other stressors (e.g. hypoxia), this could pose a severe threat to clam’s survival and aquaculture.

A3 MASTERS OF NONE: THE IMPACTS OF MULTIPLE STRESSORS ON PERFORMANCE IN AQUATIC ORGANISMS

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A3.1 CHAPERONE-MEDIATED AUTOPHAGY IN FISH: A KEY FUNCTION IN THE MIDST OF A STRESSFUL ENVIRONMENT

Wednesday 5 July 2023

POSTER SESSION

Simon Schnebert (INRAe, France), Emlio José Vélez Velázquez (INRAe, France), Maxime Goguet (INRAe, France), Karine Dias (INRAe, France), Vincent Véron (INRAe, France), Florian Beaumatin (INRAe, France), Amaury Herpin (INRAe, France), Beth Cleveland (USDAARS, United States), Iban Seiliez (INRAe, France)

simon.schnebert@inrae.fr

Chaperone-mediated Autophagy (CMA) is a protein degradation pathway that helps maintain cellular proteostasis in response to various stressors such as starvation, oxidative stress, and hypoxia. While CMA has been well described in mammals, it was only recently evidenced in fish. This discovery has provided new and exciting insights into the role of CMA in these species, which are facing increasingly stressful environmental events. In the present study, we first show that CMArelated factors are ubiquitously expressed during early development as well as in several adult tissues of rainbow trout (Oncorhynchus mykiss), a major aquaculture species. An in vitro CMA activity assay using isolated lysosomes confirmed that rainbow trout also exhibits CMA activity, which increases 21-fold during nutrient deprivation, a known CMA inducer. To understand the physiological role of CMA in trout, we generated a knock-out (KO) line lacking a key CMA rate-limiting gene, the lysosomal-associated membrane protein 2a (lamp2a), using CRISPR-Cas9 genome editing. Our findings showed that the deficient fish experienced significant disruptions in both carbohydrate and fat metabolisms. In addition, key enzymes and components of pathways involved in the defense against oxidative stress were upregulated. Taken together, these findings show that CMA is a critical pathway that shapes a distinct part of the proteome related to major metabolic pathways and plays a pivotal role in protecting against environmental threats by maintaining cellular homeostasis.

A3.2 DOES A HOT DAY EQUAL A HEATWAVE? COMPARING PHYSIOLOGICAL PERFORMANCE OF MYTILUS CALIFORNIANUS TO ACUTE AND MULTI-DAY THERMAL STRESS EVENTS

Wednesday 5 July 2023 POSTER SESSION

Sarah J Nancollas (University of California Davis, United States), Anne E Todgham (University of California Davis, United States)

snancollas@ucdavis.edu

Intertidal organisms live in a dynamic environment where important determinants of physiological performance, such as temperature and food availability, can often fluctuate unpredictably. Despite this, much of our understanding of thermal physiology in intertidal organisms is based on organisms acclimated to constant or predictable conditions and exposed to a single acute (often lethal) thermal stress event. Recent climate change models indicate that there will be an increase in multiday sublethal thermal stress events (heatwaves). Consequently, there is a growing need to understand whether predictions of physiological performance based on acute thermal ramps can be extrapolated to accurately inform performance during heatwave events, using organisms acclimated to conditions that more accurately reflect the complexity of their natural environment. We examined how acclimation to different levels of thermal predictability (no, predictable, unpredictable) combined with high or low food availability shape cardiac performance during an acute thermal ramp versus a threeday heatwave in Mytilus californianus. We found that during an acute ramp, mussels acclimated to unpredictable regimes had the highest cardiac capacity and thermal tolerance, but there was no difference between food groups. However, during the heatwave there was no difference in cardiac capacity between thermal regimes, but low food groups exhibited higher cardiac capacities than high food groups. Our results indicate that performance during a ‘hot day’ does not necessarily equate to comparable performance during a heatwave and extrapolating performance predictions based on acute responses could result in inaccurate estimations of intertidal organism performance in future climate change scenarios.

ORGANISED BY: ALEXIS KHURSIGARA (THE UNIVERSITY OF NORTH TEXAS), ANGELINA DICHIERA (THE UNIVERSITY OF BRITISH COLUMBIA)

A3.3 EFFECTS OF REPEATED ACUTE HYPOXIC STRESS ON HAEMATOLOGICAL, PHYSIOLOGICAL AND GENE EXPRESSION RESPONSE IN RAINBOW TROUTONCORHYNCHUS MYKISS.

Wednesday 5 July 2023 POSTER SESSION

Nuria Ruiz (Universitat Autònoma de Barcelona, Spain), Irene García-Meilán (Universitat de Barcelona, Spain), Mariana Teles (Universitat Autònoma de Barcelona, Spain), Ali Rheza Khansari (Universitat Autònoma de Barcelona, Spain), Lluís Tort (Universitat Autònoma de Barcelona, Spain)

99.ruiz.n@gmail.com

Oxygen is a limiting factor both in the environment and production systems, so reduction may become a stressor. Diel cyclic hypoxia may occur with varying frequency and duration in freshwater habitats. Under a stressful situation fish activate the hypothalamic-pituitaryinterrenal axis (HPI) which triggers the release of cortisol that induces secondary and tertiary responses. The recovery of individuals subjected to such stressors depends on their ability to modulate physiological, biochemical, and behavioural responses to maintain metabolic functions and homeostasis. Thus, the aim of this study is to determine the response of rainbow trout under repeated hypoxia, as a type of multiple stressors. The methodology of the experiment consisted of dividing the fish randomly in 5 different treatment groups, 2 control groups and 3 hypoxia groups. Every exposure consisted in decreasing the dissolved oxygen concentration from 8mg O2 /L to 2mg O2 /L for 1 hour. After the exposure the fish were placed into a recovery tank for 1, 6 or 24h and subsequently sampled for blood, skin, gills, and intestine. Haematological and physiological results show a habituation of the fish to repeated hypoxia in different parameters such as haematocrit, haemoglobin, mean corpuscular volume, plasma lactate and plasma cortisol. Regarding the gene expression results, significant changes were observed ingr1, crh, hif-1. Il1b, il10. The overall results show a tolerance and a certain habituation of an oxygen sensitive species, such as rainbow trout to this type of repeated hypoxia.

A3.4 EFFECTS OF WARMING ON THE METABOLIC DISRUPTION CAUSED BY A HYPOLIPIDEMIC DRUG GEMFIBROZIL IN A MODEL MARINE BIVALVE MYTILUS EDULIS

Wednesday 5 July 2023 POSTER SESSION

Halina Falfushynska (University of Rostock, Germany), Eugene Sokolov (Leibniz Institute for Baltic Sea Research, Germany), Inna M Sokolova (University of Rostock, Germany)

halina.falfushynska@uni-rostock.de

Hypolipidemic drugs are ubiquitous in global markets, and their incomplete removal from wastewater treatment plants often results in their release into aquatic environments, posing a risk of toxicity to resident biota. We propose that these drugs can act as metabolic disruptors in non-target marine organisms, such as the mussel Mytilus edulisand that these effects may be exacerbated by warming. To elaborate, we studied the mechanisms of toxicity of gemfibrozil (GFB) on the cellular metabolism and stress-responsive systems of

M. edulis. Mussels were exposed to 25 μg L−1 GFB for 14 days at control (15°C) and elevated (20°C) temperatures. Our results showed that GFB exposure caused significant oxidative stress inM. edulis, as evidenced by the accumulation of lipid and protein oxidation products, suppression of total antioxidant capacity, and depletion of glutathione. Additionally, exposure to GFB resulted in altered energy metabolism, accumulation of methylglyoxal and activation of the glyoxalase system, indicating metabolic disorders and carbonyl stress.

Overall, our findings suggest that GFB disrupts normal lipid and carbohydrate metabolism and causes oxidative stress in non-target marine organisms such as M. edulis. This could have adverse implications for the health of coastal mussel populations. Interestingly, elevated temperature did not enhance the toxicity of GFB. Moreover, GFB had no effect on amino acid metabolism or urea cycle, irrespective of temperature. Our results emphasize the need for a better understanding of the effects of environmental pollutants on non-target organisms and highlight the potential risks associated with the release of pharmaceuticals into aquatic ecosystems.

A3.5 THERMAL ACCLIMATION AFFECTS FITNESS COMPONENTS DIFFERENTLY IN GASTROPODS WITH DIFFERENT REPRODUCTIVE MODES

Wednesday 5 July 2023 POSTER SESSION

Ahmed S. A. Abbas (University of Plymouth, United Kingdom), John I. Spicer (University of Plymouth, United Kingdom), Robert Ellis (University of Exeter, United Kingdom), Manuela Truebano (University of Plymouth, United Kingdom)

ahmed.abbas@plymouth.ac.uk

Evaluating the acclimation capacity of marine organisms to increased water temperatures is essential to predict populations’ responses to ocean warming. While many studies have documented the acclimation capacity of marine ectotherms, fewer consider the fitness costs associated with this capacity. The potential tradeoffs between reproductive and somatic growth and/or survival, are likely to differ between species with different reproductive modes, thus reproductive investment. Here, we investigate the effects of thermal acclimation on some fitness traits in two congener gastropod species with different reproductive modes, the oviparous Littorina littorea and the ovoviviparous Littorina saxatilis. Scope for growth (SfG), survival, and reproductive output were measured under three acclimation temperatures representing current annual average temperature, summer extremes, and projected end-of-century summer temperatures. At the highest temperature tested, L. littorea had high survival associated with a series of physiological adjustments, but experienced a reduction in SfG, and suppression of reproduction. L. saxatilis showed similar physiological adjustments, but had dramatically reduced survival and SfG, while maintaining reproductive output. We suggest that under thermal stress, energy allocation differs between the two congeners. We discuss the costs of short-term thermal acclimation, and the potential trade-offs between reproduction and survival in species with different reproductive modes.

A3.6 OPTIMIZING BIOMARKER-BASED TOXICITY ASSESSMENT FOR CADMIUM EXPOSURE IN BIVALVE MOLLUSKS: INSIGHTS FROM ADVERSE OUTCOME PATHWAYS

Wednesday 5 July 2023 POSTER SESSION

Halina Falfushynska (University of Rostock, Germany), Olaf Dellwig (Marine Geology Leibniz Institute for Baltic Sea Research, Germany), Inna M Sokolova (University of Rostock, Germany)

halina.falfushynska@uni-rostock.de

Technogenic metals such as cadmium are released into the environment from different sources, causing serious ecological risks for wildlife and contributing to declining biodiversity. We propose a new approach for optimizing biomarker-based toxicity assessment based on adverse outcome pathways, which associate molecular initial events with outcomes at higher levels of biological organization. The study examined the accumulation of cadmium in the digestive gland and gills of Mytilus edulisexposed to 200 – 600 ug·L-1 cadmium for 14 days and its effects on selected biochemical and physiological indices. The results showed that cadmium level in tissues increased linearly with exposure concentration. Although cadmium exposure didn’t affect mussels’ condition index, it did have significant negative effects on their filtration rate and scope for growth at the highest concentration. These effects were associated with impaired byssus production, increased hemocyte mortality, and affected functional traits of hemocytes. We also observed oxidative stress, as evidenced by reduced total antioxidant capacity and thiol pool, increased lipid peroxidation, and increased autophagy and cellular damage inM. edulis tissues. Moreover, cadmium exposure caused an increase in the metallothioneins level in digestive gland. Using random forest analysis, we identified a minimal set of biomarkers that indicate adverse health effects of cadmium. These included hemocyte mortality and acid phosphatase activity, nitric oxide and metallothioneins in the digestive gland, and clearance rate. Overall, our findings suggest that bioenergetic misbalance and oxidative stress are the main drivers of sub-acute Cd toxicity in mollusks, although metallothioneins may partially compensate for these effects.

Coastal acidification corresponds to the lowering of seawater pH, which poses a threat to bivalves as they rely on dissolved calcium carbonate to form and maintain their shell. This can lead to decreased growth rates, increased predation susceptibility, and reduced fitness of bivalve populations. Understanding the effects of coastal acidification on bivalves is critical for predicting global change impacts on coastal ecosystems and developing effective conservation strategies. The flat oysterOstrea edulis, a species endemic to European coasts, is an engineering species that plays an essential role in benthic habitats but has declined dramatically due to anthropogenic impacts and diseases. Two experiments were conducted using an automatized device to investigate the ecophysiological response of the flat oyster to acidification under fed and unfed conditions. First, fifteen oysters were exposed to 12 decreasing levels of pH ranging from 8.05 to 6.4 (24h per pH level) during which clearance and respiration rates were measured. Assimilation efficiencies were calculated every three days using the biodeposition method. Results indicate that the clearance rate remained unaffected above pH 7.30, but decreased linearly below until feeding stopped at pH 6.4. Assimilation dropped sharply (80% to 15%) at levels lower than 7.0, and respiration activity also decreased below 7.0. under unfed conditions, respiration rates showed a larger inter-individual variability; however, 7.0 also appeared to be the tipping point. These findings, essential for the parametrization of bioenergetics models and the projection of acidification effects also show thatOstrea edulisis a species rather resilient to low pH conditions.

A3.8 SALINITY EFFECTS ON A NOVEL POPULATION OF ESOPHAGEAL IONOCYTES IN EELPOUT

Wednesday 5 July 2023 POSTER SESSION

Amirhossein Ghaemian (Wilfrid Laurier University, Canada), Patrícia Ferreira (Wilfrid Laurier University, Canada), Kim Birnie-Gauvin (Technical University of Denmark, Denmark), Kim Aarestrup (Technical University of Denmark, Denmark), Jonathan Wilson (Wilfrid Laurier University, Canada)

amirghaemian7@gmail.com

Wednesday 5 July 2023 POSTER SESSION

Emilien Pousse (Laboratoire des Sciences de l'Environnement Marin - Ifremer, France), Ika Paul-Pont (Laboratoire des Sciences de l'Environnement Marin - CNRS, France), Arnaud Huvet (Laboratoire des Sciences de l'Environnement Marin - Ifremer, France), Elisabeth Le Mouillour (Laboratoire des Sciences de l'Environnement Marin - Ifremer, France), Carole Di Poi (Laboratoire des Sciences de l'Environnement MarinIfremer, France)

emilien.pousse@ifremer.fr

Fishes use different osmoregulatory strategies depending on the salinity of their external environment to maintain internal water and ion balance. Marine fish drink water to osmoregulate, with the esophagus starting with the process of desalinization by absorbing salts from the ingested water. The water that enters the intestine is iso-osmotic and is absorbed by solute-linked water uptake. The excess salt that is taken up is excreted by the gills via mitochondrion-rich chloride cells. The eelpout (Zoarces viviparus) is a euryhaline fish with unusual esophageal ionocytes displaying similar localization of salt transporters to gill chloride cells, suggesting an unexpected secretory function. This counter-intuitive function would likely hinder the process of osmoregulation by counteracting desalinization (salt absorption). Here we tested the hypothesis that the expression of osmoregulatory transporters in the esophagus is modulated by osmotic stress. The expression of different salt transporters in the gill, esophagus and kidney were compared in eelpout acclimated to 5, 15 and 30 ppt salinity using real-time PCR and immunohistochemistry. We did not find changes in esophageal ionocytes numbers, suggesting a lack of salinity dependency. Analysis of transporter expression changes between the different salinities and tissues is on-going and will help elucidate the eelpout’s osmoregulatory strategy and the role of these esophageal ionocytes.

A3.7 PERFORMANCE RESPONSE OF THE EUROPEAN FLAT OYSTER OVER A WIDE DECREASING RANGE OF PH AND UNDER FED AND UNFED CONDITIONS

A3.9 EFFECTS OF ENVIRONMENTAL STRESSES ON THE PROTEIN KINASE R (PKR) GENE EXPRESSION OF THE GIANT GROUPER, EPINEPHELUS LANCEOLATUS

Wednesday 5 July 2023 POSTER SESSION

Sih-Shien Lee (National Cheng Kung University, Taiwan)

c64094712@gs.ncku.edu.tw

The giant grouper is a stenohaline teleost found in tropical and subtropical waters. It is also an important economic fish species. Fish health can be impacted by a variety of environmental factors, including salinity, temperature, and water pathogens. In response to environmental stress, elevated expression of the protein kinase R (PKR) was found in vertebrates for regulating immune responses and maintaining physiological homeostasis. In this study, the expression of PKR gene in the giant grouper was examined under three stressful conditions - salinity, temperature, and chemicals that mimic pathogens. For the salinity experiments, four groups were studied, including hypersaline (50‰), hypertonic (35‰), isotonic (10‰), and hypotonic (5‰) group. Moreover, three groups were analyzed in the temperature experiments, including the high- (36°C), normal- (28°C), and low(20°C) temperature groups. In the pathogen-mimicking experiments, the Poly I:C was applied to simulate viruses and the LPS was used to simulate bacteria. When grouper larvae were exposed to environmental temperature changes, PKR mRNA expression of the whole larva was significantly higher in the low-temperature group than the normaltemperature and high-temperature groups. Most tissues of juveniles also showed higher PKR mRNA levels in the low-temperature group. Furthermore, pathogen-mimicking experiments revealed that the PKR mRNA levels in the Poly I:C injected larvae were significantly higher than the LPS injection group. In summary, PKR mRNA expression in the giant grouper increased with ambient stresses including simulated virus injection, indicating that grouper PKR may be involved in modulation of immune responses as well as virus resistance.

A3.10 POPULATION (IN)DEPENDENT EFFECTS OF WATER PH AND HUMIC SUBSTANCES ON EMBRYONIC DEVELOPMENT TIME AND HATCHING

SUCCESS IN A FRESHWATER TELEOST

Wednesday 5 July 2023 POSTER SESSION

Kristina Noreikiene (Institute of Veterinary Medicine and Animal Sciences Estonian University of Life Sciences, Estonia),

Karl-Erik Aavik (Institute of Veterinary Medicine and Animal Sciences

Estonian University of Life Sciences, Estonia), Siim

Kahar (Institute of Veterinary Medicine and Animal Sciences

Estonian University of Life Sciences, Estonia), Magnus

Lauringson (Institute of Veterinary Medicine and Animal Sciences

Estonian University of Life Sciences, Estonia),

kriste.noreikiene@gmail.com

Environmental predictability is an important facet acting on multiple timescales. Consistently predictive environments may facilitate habitat-specific evolutionary changes. However, if conditions fluctuate unpredictably, specific phenotypes may fall beyond the optimum. For aquatic organisms water hydrochemistry is of utmost importance, but recent changes of freshwater environment may go beyond what organisms and ecosystems have experienced in an evolutionary timescale. Here we investigated early-life adaptation to water pH and humic substances in Eurasian perch (Perca fluviatilis) from two clear-water (high pH, low humic substances) and two humic-water (low pH, high humic substances) populations.We conducted two experiments where in vitro fertilized eggs were distributed into Petri dishes with two contrasting natural lake water treatments (exp.1) and artificial water with 3 pH and 2 humic substance treatments (exp.2). Embryo survival and hatching success was monitored for 14 days post fertilization. This resulted in >10 000 data records which we analysed using several statistical approaches to uncover factors affecting hatching success under different environmental conditions. Our study shows for the first time that perch eggs are able to develop normally within a minimal amount of water (5 ml). These results enable us to successfully conduct complex experiments with a high number of replicates, which may be of a particular interest for experimental or developmental biologists.

A3.11 IMPACTS OF CHRONIC THERMAL STRESS ON HYPOXIA TOLERANCE ACROSS POPULATIONS OF A LONG-LIVED FISH

Wednesday 5 July 2023 POSTER SESSION

Simon Schnebert (INRAe, France), Emlio José Vélez Velázquez (INRAe, France), Maxime Goguet (INRAe, France), Karine Dias (INRAe, France), Vincent Véron (INRAe, France), Florian Beaumatin (INRAe, France), Amaury Herpin (INRAe, France), Beth Cleveland (USDAARS, United States), Iban Seiliez (INRAe, France)

simon.schnebert@inrae.fr

Konrad Taube (Institute of Veterinary Medicine and Animal Sciences

Estonian University of Life Sciences, Estonia), Riho

Gross (Institute of Veterinary Medicine and Animal Sciences

Estonian University of Life Sciences, Estonia), Anti Vasemägi (Institute of Freshwater Research Swedish University of Agricultural Sciences, Sweden)

Angelina Dichiera abstract should be: While flexible phenotypic responses to environmental change is thought to be beneficial in dynamic environments, long-lived species may also display similar phenotypic flexibility regardless of environment as they encounter environmental change over large temporal scales. White sturgeon (Acipenser transmontanus) are one of the largest and longest-lived freshwater fish in North America but through historical overfishing and current range restrictions, many populations are at risk. In concert with global increases in temperature and more frequent heatwaves, urbanization and habitat fragmentation can increase the prevalence and severity of hypoxia (decreased oxygen levels). These rapid environmental changes pose threats for sensitive individuals, but we expect long-lived species demonstrate phenotypic flexibility in response to multiple stressors. We investigated the impacts of thermal acclimation on hypoxia tolerance across three distinct populations of white sturgeon. Fish from the Fraser and Nechako Rivers (British Columbia, Canada) were acclimated to either control temperature (14°C) or warm temperature (20°C, recommended river temperature limit for salmonids in BC), and fish from the Sacramento River (California, USA) were acclimated to five temperatures across their native range (14-22°C). Hypoxia tolerance was evaluated using either the critical

oxygen tension (Pcrit) method, time to loss of equilibrium (LOE), or incipient lethal oxygen saturation (ILOS) method at acclimation and acute temperatures to characterize phenotypic responses. We find that warm-acclimated fish demonstrate pronounced compensatory responses to temperature (e.g., maintained hypoxia tolerance). When paired with biochemical and tissue-level metrices, we can holistically assess how white sturgeon cope with multiple stressors, and if these plastic responses are population-specific.

A3.1 CHAPERONE-MEDIATED AUTOPHAGY IN FISH: A KEY FUNCTION IN THE MIDST OF A STRESSFUL ENVIRONMENT

Wednesday 5 July 2023 POSTER SESSION

Angelina M. Dichiera (The University of British Columbia, Canada), Kelly D. Hannan (The University of California Davis, United States), Garfield T. Kwan (The University of California Davis, United States), Nann A. Fangue (The University of British Columbia, United States), Patricia M. Schulte (The University of British Columbia, Canada), Colin J. Brauner (The University of British Columbia, Canada)

dichiera@zoology.ubc.ca

While flexible phenotypic responses to environmental change is thought to be beneficial in dynamic environments, long-lived species may also display similar phenotypic flexibility regardless of environment as they encounter environmental change over large temporal scales. White sturgeon (Acipenser transmontanus) are one of the largest and longest-lived freshwater fish in North America but through historical overfishing and current range restrictions, many populations are at risk. In concert with global increases in temperature and more frequent heatwaves, urbanization and habitat fragmentation can increase the prevalence and severity of hypoxia (decreased oxygen levels). These rapid environmental changes pose threats for sensitive individuals, but we expect long-lived species demonstrate phenotypic flexibility in response to multiple stressors. We investigated the impacts of thermal acclimation on hypoxia tolerance across three distinct populations of white sturgeon. Fish from the Fraser and Nechako Rivers (British Columbia, Canada) were acclimated to either control temperature (14°C) or warm temperature (20°C, recommended river temperature limit for salmonids in BC), and fish from the Sacramento River (California, USA) were acclimated to five temperatures across their native range (14-22°C). Hypoxia tolerance was evaluated using either the critical oxygen tension (Pcrit ) method, time to loss of equilibrium (LOE), or incipient lethal oxygen saturation (ILOS) method at acclimation and acute temperatures to characterize phenotypic responses. We find that warm-acclimated fish demonstrate pronounced compensatory responses to temperature (e.g., maintained hypoxia tolerance). When paired with biochemical and tissue-level metrices, we can holistically assess how white sturgeon cope with multiple stressors, and if these plastic responses are population-specific.

Liam R Tigert (University of Toronto Scarborough, Canada liam.tigert@mail.utoronto.ca

Due to changes in land use practices, hypoxia is a concern in coastal areas. Other climate change conditions such as ocean acidification have been shown to impair the sensory systems of marine fish, however the effects of hypoxia on sensory systems is greatly understudied. Olfaction is an important sense, allowing fish to sense over long distances, helping them to locate food, and avoid predators. To determine if hypoxia affects olfaction in a fish, threespine stickleback (Gasterosteus aculeatus) were exposed to either control (8.5 mg/L O2 , ~90% saturation) or mild hypoxia for one week (4.0 mg/L O2 , ~50% saturation), and their behavioural response to shark bile was assessed using a choice flume. In response the odorant, fish in control conditions did not avoid the odorant (p=0.48), but they significantly increased the amount of time spent freezing (p=0.02), another anti-predator behaviour. A combined predator response score, consisting of the amount of time avoiding the odorant or freezing in response was also calculated. The control fish had a strong response to the odorant (p=0.01) showing that sticklebacks responded to the predator odour. However, there was a significant difference in freezing behaviour between the groups with hypoxia exposed fish spending significantly less time freezing in response to a predator cue (p=0.04). This shows that hypoxia had a direct effect on the ability of stickleback to detect and respond to an ecologically relevant odorant. Future studies will investigate whether more severe hypoxia or combined stressors would have a more severe effects on olfaction in sticklebacks.

A3.13 WHEN THE GOING GETS TOUGH, SEX MATTERS? SEX-SPECIFIC WITHIN AND TRANSGENERATIONAL EFFECTS OF MARINE HEATWAVES AND HYPOXIA ON ACARTIA TONSA

Wednesday 5 July 2023 POSTER SESSION

Fanny Vermandele (University of Quebec at Rimouski, Canada), Ellia Roy (University of Quebec at Rimouski, Canada), Matthew Sasaki (University of Vermont, United States), Gesche Winkler (Institut des sciences de la mer de Rimouski University of Quebec at Rimouski, Canada), Hans G. Dam (University of Connecticut, United States), Diana Madeira (University of Aveiro, Portugal), Piero Calosi (University of Quebec in Rimouski, Canada)

fanny.vermandele@uqar.ca

Wednesday 5 July 2023 POSTER SESSION

Because oxygen and temperature are fundamental to biological processes, the increase in the severity and frequency of hypoxic events and marine heatwaves (MHW) is expected to have dire consequences for marine ecosystems, particularly coastal and estuarine ones. However, the short- and long-term consequences of these events on the physiology of marine ectotherms remain poorly understood. In particular, sex-specific responses, which have consequences for population dynamics, are poorly studied. Therefore, we examined the acute within-generational response to hypoxia and MHW, and the transgenerational plastic responses during the recovery phase, on males and females of the foundational marine copepod species, Acartia tonsa. We measured survival, metabolic rates and upper thermal limits on mature males and females (F0) following a five-day exposure to the combined effects of hypoxia and a MHW, and on their offspring (F1), raised under control conditions, once they reached adulthood.

A3.12 CAN MILD HYPOXIA AFFECT THE RESPONSE OF A COASTAL FISH TO A PREDATOR CUE?

Preliminary results suggest that F0 copepods exposed to MHW and combined hypoxia and MHW have higher metabolic rates and thermal limits, while survival is not affected. Females show a greater thermal tolerance when compared to males. Transgenerational effects were also evident as offspring from the parental MHW treatment showed lower survival when compared to all other treatments, but no changes in metabolic rates and thermal tolerance. These results show the importance of considering sex-specific and transgenerational plastic responses to extreme events in global change studies.

A3.14 TRADE-OFFS BETWEEN OSMOREGULATION AND DIGESTION IN THE TELEOST OPSANUS BETA: SPECIFIC DYNAMIC ACTION, STANDARD METABOLIC RATE, AND GROWTH

Wednesday 5 July 2023 POSTER SESSION

LeeAnn C Frank (University of Miami, United States), Emma B Esch (University of Miami, United States), John D Stieglitz (University of Miami, United States), Martin Grosell (University of Miami, United States)

lcf51@miami.edu

The cost of osmoregulation in teleosts has been extensively studied, with inconsistent results. In past experiments, the cost of osmoregulation has been assessed on unfed fish exclusively. The present study aimed to determine if trade-offs exist between osmoregulation and digestion measured both as specific dynamic action (SDA) and growth. To quantify SDA, Gulf toadfish, Opsanus beta, acclimated to either 9, 35, or 60 ppt salinity, were fed 5% body mass and were placed in respirometers for 96h. Standard metabolic rate was significantly higher in 60 ppt compared to 9 ppt. Contrary to expectations, the duration of SDA was significantly higher in 60 ppt and the magnitude of SDA increased rather than decreased with salinity. Similarly, the peak metabolic rate post-feeding was significantly reduced in 9 ppt compared to 35 ppt. To assess the effects of salinity on growth, toadfish were fed 3% body mass 3 times a week for ~ 2 months in 9, 35 and 60 ppt. There was a trend towards a higher specific growth rate in 60 ppt suggesting more efficient digestion and assimilation. These unexpected results may be explained by sodium availability in the intestinal lumen which facilitates nutrient absorption and therefore SDA and possibly growth in the Gulf toadfish.

A3.15 THE IMPACT OF CHANGING SALINITIES ON CORAL REEF FISH PERFORMANCE

Wednesday 5 July 2023

POSTER SESSION

Daniele D'Agostino (New York University - Abu Dhabi, United Arab Emirates), Grace Vaughan (New York University - Abu Dhabi, United Arab Emirates), Matthew Mittchell (New York University - Abu Dhabi, United Arab Emirates), John A Burt (New York University - Abu Dhabi, United Arab Emirates)

dd3333@nyu.edu

Understanding the physiological responses of coral-associated fish to salinity changes is crucial for assessing the impacts of climate

change and human activities (such as desalination) on stenohaline fish populations. In this study, we investigated the effects of salinity on the performance (i.e., feeding, growth, stress, metabolism, and mortality) of a common coral-associated fish (Ecsenius pulcher) acclimated to salinities ranging from 30 to 52 PSU. We compared individuals in the environmentally extreme Arabian/Persian Gulf (mean salinity 42-45 PSU) and the adjacent comparably benign Oman Sea (37 PSU). Salinity had a negative effect on fish feeding and growth across populations and salinity treatments (i.e., lower or higher conditions); however, fish showed higher stress levels and mortality only at higher salinity, whereas higher salinity had a significant negative effect on metabolism (i.e., reduced aerobic scope) only in the Oman Sea populations. Overall, changes in salinity had a stronger negative effect on the Oman Sea population, indicating that fish from the Arabian Gulf may be better able to acclimate to changing environmental conditions. Our results highlight the potential importance of changes in salinity affecting feeding, growth, stress, and metabolism in stenohaline organisms and the need to consider the effects of multiple stressors when investigating the consequences of future climate change on fish performance.

A3.16 INTERACTIONS AMONG CORAL BLEACHING, SOCIAL DYNAMICS, AND INDIVIDUAL THERMAL PREFERENCE ON THE SELECTED THERMAL REGIME OF A COLONIAL CORAL REEF FISH

Wednesday 5 July 2023 POSTER SESSION

Marie Levet (Université de Montréal, Canada), Suzanne C Mills (CRIOBE, France), Emil Christensen (University of Glasgow, United Kingdom), Ricardo Beldade (Pontificia Universidad Católica de Chile, Chile), Jules Schligler (CRIOBE, France), Shaun S Killen (University of Glasgow, United Kingdom)

marie.levet@umontreal.ca

Ongoing climate change is having numerous adverse effects on coral reef communities, including increases in the frequency and severity of bouts of coral bleaching. There are also direct effects of warming on the physiology and behaviour of ectothermic coral reef residents. While individual fish can theoretically select their individually optimal thermal habitat, environmental factors such as the presence of coral bleaching or conspecifics may modulate their ability to occupy their preferred thermal niche. We tested the degree to which individual thermal preference, conspecific presence, and coral bleaching interact to influence the selected thermal regime of individual Humbug damselDascyllus auranus, a colonial coral reef species with a strong social structure. After measurement of thermal preference using a shuttlebox, each fish was exposed to eight different choice treatments, with varying combinations of microhabitats consisting of healthy coral vs bleached coral, a relatively warm vs cool temperature, and the presence of conspecifics vs absence of conspecifics. Early results indicate strong social cohesion in this species, even when the stimulus conspecifics are located in a putatively undesirable microhabitat, such as that containing bleached coral or that is warmer or cooler than the preference of the focal individual. The results here highlight the importance of considering the modulating effects of the social environment on coral reef fish behaviour, including the behavioural stress responses associated with biotic and abiotic stressors.

A3.17 IMPACTS OF ANTHROPOGENIC STRESSORS ON SOCIAL GROUP COHESION AND INDIVIDUAL SOCIABILITY IN FISH: A SYSTEMATIC REVIEW

Wednesday 5 July 2023 POSTER SESSION

Izzy C Tiddy (University of Glasgow, United Kingdom), Amelia Munson (University of Glasgow, United Kingdom), Shaun S Killen (University of Glasgow, United Kingdom)

2676688t@student.gla.ac.uk

Fish grouping behaviour is an important fitness-related trait, allowing avoidance of predators and improving foraging success. However, there is increasing evidence of disruption of fish grouping behaviour as a result of anthropogenic disturbance. As stressors become more intense and frequent, the effects on fish behaviour may be magnified and affect the ability of fish species to maintain beneficial behaviours and adapt to changing conditions. This study aimed to conduct a systematic review of the effects of temperature, hypoxia, acidity, noise, and chemical pollutants on individual sociability and group cohesion in shoaling and schooling fishes. Evidence was found for a reduction in group cohesion at high temperatures and low oxygen levels. Marine fishes appear to be more strongly negatively affected by acidity compared with freshwater species, however results are inconsistent and more studies are required. Artificial noise can lead to an increase in group cohesion, though habituation to noise can occur over relatively short time periods. Evidence was found of reduced sociability following exposure to antidepressants, anti-inflammatories, and analgesics, as well as metals and industrial compounds, though effects of chemical pollutants on group cohesion were less consistent. In studies of multiple stressors, again mainly negative trends were present in sociability and group cohesion, though more studies are needed. Overall, there is evidence that anthropogenic stressors significantly impact sociability and group cohesion in fish species, potentially reducing survival and adaptability in shoaling and schooling species.

A3.18 IN THE HOT SEAT: HOW MULTIPLE ENVIRONMENTAL DRIVERS SHAPE PHYSIOLOGICAL PERFORMANCE OF MUSSELS IN A WARMING WORLD

Wednesday 5 July 2023 POSTER SESSION

Sarah J Nancollas (University of California Davis, United States), Anne E Todgham (University of California Davis, United States)

snancollas@ucdavis.edu

Recent climate change models indicate that there will be an increase in thermal unpredictability and the frequency and intensity of hot days. Many sessile intertidal organisms live close to their upper thermal limits and experience a high degree of thermal unpredictability due to combined effects of solar radiation and tidal movement. How thermal unpredictability operates in microhabitats with different media, such as tidepool (aquatic) or tidally exposed (aerial) environments is poorly understood, especially when coupled with other important determinants of performance, such as food availability. Understanding how these factors interact to influence performance under increasing temperatures is essential towards understanding the effects of climate

change on intertidal communities. We examined how acclimation to different levels of thermal predictability (no, predictable, unpredictable) with high or low food availability shapes performance during an acute thermal ramp in Mytilus californianus in two microhabitat treatments: tidepool and tidally exposed. Mussels were warmed at a rate of 6.3°C/hour for 6 hours in their respective medium (water or air). Heart rate was monitored continuously, and tissues samples were taken for biochemical analyses at 20°C, 30°C and 40°C. We found that tidally exposed mussels had higher upper thermal limits than tidepool mussels. Mussels from the unpredictable regimes exhibited the highest cardiac capacity and thermal tolerance, supported by elevated initial glycogen stores and high food availability led to increased cardiac capacity. Our results suggest that while thermal unpredictability may aide in increasing performance, hotter days could critically impact tidepool mussels and have severe consequences for intertidal community composition.

A3.19 NON-LINEAR NEGATIVE EFFECT OF CHRONIC HYPOXIA ON THE UPPER THERMAL LIMIT OF THE ACADIAN REDFISH SEBASTES FASCIATUS

Wednesday 5 July 2023 POSTER SESSION

Elodie Beaulieu (University of Quebec at Rimouski, Canada), Joëlle Guitard (Institut des sciences de la mer University of Quebec at Rimouski, Canada), David Deslauriers (Institut des sciences de la mer University of Quebec at Rimouski, Canada), Denis Chabot (Department of Fisheries and Oceans Canada Maurice-Lamontagne Institute, Canada), Piero Calosi (University of Quebec at Rimouski, Canada)

elodie.beaulieu@uqar.ca

In the Estuary and the Gulf of St. Lawrence (Quebec, Canada), the recent massive recrudescence of commercially important redfish (Sebastes mentella and S. fasciatus), currently under fishing moratorium, is of interest due to its potential impacts on this ecosystem. The return of redfish has the potential to significantly increase predation pressure on the economically and ecologically important northern shrimp Pandalus borealis. Further, this recent redfish population increase should eventually permit reopening of its fishery. However, how this species will fare under ongoing ocean changes (e.g., ocean warming and deoxygenation) is unknown, thus representing an important knowledge gap. Consequently, the aim of this project was that to study the effect of a long-term (35 week) exposure to eight levels (25, 35, 45, 55, 65, 75, 85, 100 % air-saturated water (ASW)) of dissolved oxygen on the upper thermal limit (UTL) of the Acadian redfish Sebastes fasciatus. After exposure, all the fish from the same exposure tank were subjected together to a critical thermal maximum challenge: starting from the exposure temperature of 5 °C, temperature was increased at a rate of 0.1 °C min-1 until fish lost equilibrium. Redfish UTLs were comparable between 100 and 45 % ASW but decreased significantly below 45 % ASW. Our results will contribute to the critical understanding of the physiology of the redfish and the management of its stock within the context of global changes, as well as to the development of a larger project aiming at generating bioenergetic models for this species.

A3.1 CHAPERONE-MEDIATED AUTOPHAGY IN FISH: A KEY FUNCTION IN THE MIDST OF A STRESSFUL ENVIRONMENT

Wednesday 5 July 2023 POSTER SESSION

Simon Schnebert (INRAe, France), Emlio José Vélez Velázquez (INRAe, France), Maxime Goguet (INRAe, France), Karine Dias (INRAe, France), Vincent Véron (INRAe, France), Florian Beaumatin (INRAe, France), Amaury Herpin (INRAe, France), Beth Cleveland (USDAARS, United States), Iban Seiliez (INRAe, France)

simon.schnebert@inrae.fr

TBC

A3.20 THE ROLE OF CLAUDIN-14 IN BRANCHIAL PERMEABILITY IN RESPONSE TO EXTRACELLULAR CALCIUM LEVELS

Wednesday 5 July 2023 POSTER SESSION

Patrícia G Ferreira (Wilfrid Laurier University, Canada), Xena C Montoya (Wilfrid Laurier University, Canada), Henrik Dimke (Institute of Molecular Medicine University of Southern Denmark, Denmark), Jonathan M Wilson (Wilfrid Laurier University, Canada)

pferreira@wlu.ca

High pH (pH 10) in fresh water imposes osmoregulatory challenges to fish, as ions (e.g. sodium) are lost resulting in ionoregulatory failure and ultimately death. However, previous studies have shown that increasing water hardness (i.e., increasing divalent cation concentrations) increases the survival and fitness of fish transferred to high pH water; although, the mechanisms behind this relationship remain poorly understood. Paracellular movement of ions is tightly regulated by tight-junction proteins such as claudins. In this study, we explore the potential role of Claudin-14 (Cldn14), that has been shown to be regulated by Ca2+ levels and potent blocker to Na+ permeation, in modulating gill permeability in hard waters. We hypothesize that elevated Ca2+ levels in the water lead to an upregulation of Claudin-14. This would reduce the paracellular pathways for the movement of divalent cations and Na+ , ameliorating the branchial sodium loss seen in high pH waters. Here, we report Cldn14 localization in the gills of the Mexican tetra Astyanax mexicanus and its protein and gene regulation in response to environmental pH and Ca2+ levels. We found an increase in cldn14 mRNA in the gills of A. mexicanus exposed to hard high pH water ([Ca2+ ] 1.25mM, pH 10), compared to animals held in soft high pH water ([Ca2+ ] 0.02mM, pH 10). These results suggest that Cldn14 may provide a possible mechanistic link between the protective effect of water hardness on the high pH ion imbalance observed in fishes.

A3.21 ARE SUNSCREENS BETTER TOGETHER? A COMPARISON OF

BETWEEN ISOLATED ULTRAVIOLET FILTERS AND COMPLEX OFF-THE-SHELF SUNSCREEN MIXTURES IN DAPHNIA MAGNA.

Wednesday 5 July 2023 POSTER SESSION

Aaron Boyd (University of Alberta, Canada), Sidney Martin (University of Alberta, Canada), Ally Legge (University of Alberta, Canada), Tamzin A Blewett (University of Alberta, Canada)

boyd2@ualberta.ca

Organic ultraviolet filters (UVFs) are contaminants of concern found in sunscreens and skincare products, used to protect against ultraviolet radiation. Their use in sunscreens leads to widespread environmental contamination through leaching from skin during recreational activities, threatening aquatic ecosystems. Previous research has overwhelmingly focused on the study of individual UVFs, under the assumption that the environmental toxicity of complex sunscreen mixtures can be adequately modeled through testing of each individual ingredient. This study sought to address the lack of research regarding full sunscreen mixtures by comparing the 21 d toxicity of five offthe-shelf sunscreen mixtures to their constituent individual UVFs of avobenzone, homosalate, octisalate, octocrylene and oxybenzone. Sunscreen mixtures exhibited reduced toxicity, as Daphnia survived exposure to sunscreens containing UVFs at concentrations >50x greater than the concentration of isolated UVFs causing complete mortality. Sunscreen mixtures required UVF concentrations in excess of previously measured environmental concentrations in order to induce impairments including a 70% decrease in overall reproduction and a 10fold increase in non-viable offspring. Sunscreen mixtures also reduced Daphnia growth through a 65% reduction in body mass and a 35% shorter body length, an effect not observed after exposure to isolated UVFs. Overall, these results suggest that sunscreen contamination of aquatic environments cannot be modeled by testing individual components, and the complexity of the stressor should be considered. This presents a concern, as the majority of data regarding environmental contamination and toxicity revolves around UVFs directly, with little regard for other sunscreen mixture components such as emulsifiers, fragrances and solvents.

A3.22 STRUCTURAL CHANGES IN THE GILLS AS A RESPONSE TO TOTAL SUSPENDED SOLIDS

Wednesday 5 July 2023

POSTER SESSION

Xena C Montoya (Wilfrid Laurier University, Canada), William Andrew Thompson (University of Calgary, Canada), Jonathan Wilson (Wilfrid Laurier University, Canada), Mathilakath Vijayan (University of Calgary, Canada)

mont4180@mylaurier.ca

Total suspended solids (TSS) in the water column have been linked to structural damage in fish gills. This includes hyperplasia (swelling), epithelial lifting and lamellae thickening, that could reduce the gill’s capacity for oxygen transport by increasing oxygen diffusion distance.

TOXICITY

We tested the hypothesis that elevated levels of TSS will compromise gill structural changes using salmonids (Oncorhynchus mykiss,Salvelinus fontinalis,Oncorhynchus clarkii) and non-salmonids (Rhinichthys cataractaeandPimephales promales). Fishes were exposed to TSS concentrations from 0 to 1000 mg/L for 96h in a static exposure system with aeration to maintain dissolved oxygen and sediment suspension. The assessment of gill structural damage included measuring filament thickness (FT), oxygen diffusion distance (ODD), lamellae thickness (LT), lamellae height (LH), interlamellar distance length (IDL) and epithelial lifting (EL) using whole-mount confocal microscopy. Exposure to TSS increased EL in all species suggesting gill damage. In addition, LT and ODD increased in a species-specific manner, while ILD decreased only in salmonids. The increase in LT was evident at 50 and 100 mg/L in salmonids, while in non-salmonids it was evident only at the two highest concentrations (500 and 1000 mg/L). Although ODD increased in all salmonids, there was speciesspecific differences in their sensitivity to TSS. In the non-salmonids, onlyR.cataractaeshowed an increase in ODD at all TSS concentrations tested. Overall, TSS exposure can compromise the gas exchange at the gills in a species-specific manner. These findings suggest that species sensitivity should be considered when assessing the ecological impact of TSS in our waterways.

A3.23 EFFECTS OF GLOBAL WARMING AND SALINITY

DIFFERENCES ON ENERGY METABOLISM AND CONTENT OF KRILL (THYSANOESSA INERMIS) IN ARCTIC OCEAN

Wednesday 5 July 2023 POSTER SESSION

Pauline Bourdin (University of Turku, Finland), Giovanna Mottola (University of Turku, Finland), Ella W Von Weissenberg (Novia University of Applied Sciences, Finland), Jonna Engström-Öst (Novia University of Applied Sciences, Finland), Katja Anttila (University of Turku, Finland)

pauline.bourdin@utu.fi

Global warming and radical differences in salinity can cause significant impacts on many marine organisms. They can also affect the primary production, and therefore food availability to next trophic levels. These stressors might change e.g. ion regulation, development, behavior and energy metabolism of animals. Marine species can be attributed in different categories according their ability to face narrow (stenohaline) or broad (euryhaline) ranges of salinity. Stenohaline species will need to compensate the excess of salinity by putting more effort and energy to regulate their osmotic pressure trough their gills. The global warming might exaggerate the problem. The rise of water temperature will further increase the basal metabolism especially of ectothermic animals. If the temperature rises above the species optimum and if they need to face different types of water with different salinities, species might have less energy available to growth and reproduce. The purpose of this project was to test the eco-physiological hypotheses of multiple stressors in the Svalbard archipelago and are krill, key species of marine ecosystems, able to respond to these stressors and how the stressors affect their energy metabolism and content. To do this krill were caught from six locations around Svalbard both from Antarctic and Atlantic currents with their own environmental parameters. The activity of key energy metabolism enzymes and the lipid, protein and glycogen content of the krill were measured in University of Turku. The results will reveal can krill respond to global warming and associated changes in the ocean salinity.

A3.25 TRANSGENERATIONAL TRANSCRIPTOMIC EFFECTS OF OCEAN ACIDIFICATION ON THE OLFACTORY EPITHELIUM ARE ASSOCIATED WITH A BETTER VIRAL RESISTANCE IN A MARINE FISH

Wednesday 5 July 2023 POSTER SESSION

Mishal Cohen-Rengifo (Ifremer, France), Morgane Danion (ANSES, France), Anne-Alicia Gonzalez (MGX, France), MarieLaure Begout (Ifremer, France), Alexandre Cormier (Ifremer, France), Cyril Noël (Ifremer, France), Joëlle Cabon (ANSES, France), Thomas Vitré (Ifremer, France), Felix Mark (AWI, Germany), David Mazurais (Ifremer, France)

mishal.cohen@ifremer.fr

Facing ocean acidification (OA), marine fishes can efficiently balance their acid-base homeostasis. Nonetheless, ionic regulation induces indirect effects that alters neurosensory systems and results in behavioural abnormalities. OA can also affect immune systems in marine invertebrates, but much less is known in marine fishes. How transgenerational acclimation to OA influences the magnitude of disturbances in biological processes remains an open question. Here, we exposed two generations of the European sea bass Dicentrarchus labrax to end of century predicted CO2 levels (IPCC RCP 8.5), with parents being exposed for four years and their offspring for 18 months. Our design focused on the offspring and included a transcriptomic analysis of the olfactory rosette and a viral challenge. We discovered transcriptomic trade-offs in both sensory and immune systems. RNA-Seq analysis revealed extensive regulation in genes involved in ion transport and neural signalling including the GABAergic system. Genes associated with odour transduction, synaptic plasticity, neuron excitability and wiring were up-regulated whereas genes involved in energy metabolism were down-regulated. We also detected up-regulation of numerous actors involved in innate antiviral immunity (pathogen recognition receptors and interferon-stimulated genes), which combined to the OA-induced down-regulation of the protein biosynthetic machinery may explain the better resistance we observed during a betanodavirus challenge. Our results reveal that transgenerational exposure to end of century OA conferred improved viral resistance, though as their metabolic and odour transduction programs were altered, odourmediated behaviours might be impacted. This can have consequences for how fish interacts with its environment.

A3.26 THE COLD-INDUCIBLE RNA-BINDING

OF EURYHALINE MILKFISH, CHANOS CHANOS

Wednesday 5 July 2023 POSTER SESSION

Yu-Ting Lin (National Chung Hsing University, Taiwan)

yutinglin0122@gmail.com

Fish are sensitive to aquatic environments. Rapid environmental changes (e.g., salinity and temperature) put fish under stress and further

PROTEIN

(CIRP): AN INDICATOR FOR ACUTE TEMPERATURE AND SALINITY STRESSES

threaten their lives. Euryhaline teleosts have powerful osmoregulation ability, allowing them to acclimate to a wide range of salinity changes. Even though, fish usually experience rapid osmotic stress upon salinity challenge. As a multi-stress indicator in mammals, the cold-inducible RNA-binding protein (CIRP) can be induced by both hypothermal stress and osmotic stress. Euryhaline milkfish (C. chanos) is an important aquaculture species in Taiwan and South-East Asia and can survive in a wide range of salinity fluctuations. However, the cold snaps caused high mortality of cultured milkfish during the winter. Therefore, it is crucial to identify an indicator for quantifying the degree of environmental stress in milkfish. This study aims to identify the CIRP as an indicator of milkfish under acute environmental stresses. In milkfish, two cirp genes (cirpa and cirpb) have been identified. Both genes were universally distributed, but the highest abundance was found in the brain. After exposing milkfish to the hypothermal environment (18 ℃) for 12 or 24 hours, the gene expression of cirpb was upregulated in the gill or liver by transcriptome and real-time PCR analysis. On the other hand, upon salinity challenge, the gene expression of cirpb was upregulated at 6 or 12 hours in the gill after being transferred to a hypoosmotic or hyperosmotic environment, respectively. Accordingly, cirpb could potentially be an indicator in the gill and liver of milkfish under acute temperature and salinity stresses.

A3.27 PHYSIOLOGICAL, ECOLOGICAL AND ANTHROPOGENIC DRIVERS OF BEHAVIOUR IN FORAGING SPERM WHALES

Wednesday 5 July 2023 POSTER SESSION

Alec Burslem (University of St Andrews, United Kingdom), Patrick J O Miller (University of St Andrews, United Kingdom), Saana Isojunno (University of St Andrews, United Kingdom) acb35@st-andrews.ac.uk

Lipid-store body condition is a key internal state variable for animals balancing the risk of starvation against other perceived risks such as predation threats. Animals in poor condition may be expected to prioritise immediate foraging needs over protection of future assets and therefore demonstrate greater risk tolerance to obtain foraging benefits. However, in some species where poor condition limits escape or defensive abilities, it may decrease the apparent risk tolerance of an individual independently of its needs and assets. With accumulating evidence that animals perceive certain anthropogenic activities and predation risk as analogous forms of threat, similar trade-offs are expected to drive response to anthropogenic disturbance. For longlived iteroparous species such as cetaceans, such state-dependent responses may have profound effects on the population consequences of disturbance, particularly where disturbance is accompanied by other stressors capable of influencing the animal’s physiological state. We used biologging tags to quantify tissue density (an inverse proxy for condition) and dive-level foraging states in 30 free-ranging sperm whales and investigated the association between individual behaviour and body condition during undisturbed baseline periods and controlled experimental sonar exposures. Denser individuals (presumably in poorer condition) were less likely to follow a deep-diving foraging strategy during baseline and showed subtly different responses to sonar exposures. By quantifying how physiological state may mediate response to disturbance, these results have the potential to inform frameworks for predicting the population consequences of multiple stressors in marine mammals.

A3.28 COMPARISONS OF THE PHYSIOLOGICAL PARAMETERS AND INTESTINAL MORPHOMETRY BETWEEN THE PINHEAD AND STARVED MILKFISH, CHANOS CHANOS

Wednesday 5 July 2023 POSTER SESSION

Chia-Jui Liu (Department of Life Sciences National Chung Hsing University, Taiwan), Chia-Hao Chang (Department of Life Sciences National Chung Hsing University, Taiwan), Yu-Xuan Lin (Department of Life Sciences National Chung Hsing University, Taiwan), Chun-Yi Yeh (Department of Life Sciences National Chung Hsing University, Taiwan), TsungHan Lee (Department of Life Sciences National Chung Hsing University, Taiwan)

qazwsxfrank@gmail.com

The euryhaline milkfish (C. chanos), one of the major aquaculture species in Southeast Asia, can be cultured in water of different salinities. When milkfish are exposed to certain environmrntal stressful conditions, such as water pollution, the winter season, heavy rain, or salinity change, some individuals have been observed to get the pinhead syndrome, which can cause anorexia, a thin abdomen, intestinal edema, and swimming imbalance on milkfish. In this study, the potential causes and effects of pinhead syndrome were analyzed by several physiological prameters and intestinal histology. Leptin A, an anorexigenic hormone, was found to be abnormally more expressed in milkfish with pinhead syndrome, which may be related to their lack of appetite and feeding behavior. The plasma osmolality, condition factor, hepatosmotic inxdex, intestine somatic index, enterocyte height, villi, goblet cells, sodium potassium ATPase activity and protein abudance of the pinhead milkfish were found to be similar compared to those of the 4-week starvation individuals. However, the reduction of aforementioned physiological indicators in the long-term starvation group, but not in the pinhead syndrome group, had the ability to recover in refeeding treatment. This finding suggests that the anorexic behavior of the pinhead milkfish led to its difficulty in recovery. Taken togerther, our results illustrate for the first time the physiological parameters of pinhead milkfish, but more investigation is still needed to realize how environmental or artificial stresses could lead to this syndrome.

A3.29 EFFECTS OF IRRADIANCE AND OCEAN ACIDIFICATION ON TRANSEPITHELIAL PROTON FLUX IN CORALS

Wednesday 5 July 2023

POSTER SESSION

Alexander A Venn (Centre Scientifique de Monaco, Monaco), Eric Tambutté (Centre Scientifique de Monaco, Monaco), Lucas Crovetto (Centre Scientifique de Monaco, Monaco), Natacha Segonds (Centre Scientifique de Monaco, Monaco), Sylvie Tambutté (Centre Scientifique de Monaco, Monaco)

alex@centrescientifique.mc

The formation of calcium carbonate skeletons by coral calcification forms the structural basis of reef ecosystems. To supply carbonate for their calcification reaction, corals convert it from other forms of dissolved inorganic carbon (DIC) generating H+ in the process. Transport mechanisms to remove these protons from the site of calcification are essential physiological processes driving reef formation. Recent research indicates that the resilience of corals to ocean acidification hinges on proton transport mechanisms and that these mechanisms may be shaped by irradiance.

We aim to provide a systemic, cell to organism vision of coral pH regulation and its role in defining coral resilience in ocean acidification in light and darkness. Characterizing proton flux from the internal site of calcification to seawater isn’t straightforward however, because coral possess multiple intervening cell layers and extracellular compartments. Furthermore, a transepithelial perspective of pH regulation is lacking against the backdrop of ocean acidification. Irradiance potentially favours proton transport by elevating pH due to photosynthetic activity of the coral’s symbiotic dinoflagellates, conversely internal pH gradients may be less favourable for proton transport in darkness.

Using inverted and upright in vivo confocal microscopy, we are characterising pH gradients from the coral’s calcifying cells across multiple epithelia to seawater in conditions of ocean acidification. The high spatial resolution of our analysis allows us to define sharp pH changes across layers providing mechanistic insight into how proton transport is affected by decreased seawater pH. Parallel experiments with Liquid Ion Exchange pH microelectrodes are helping validate our measurements.

A3.30 WHEN IS ENOUGH, ENOUGH? INCORPORATING ENVIRONMENTAL COMPLEXITY

INTO PHYSIOLOGICAL EXPERIMENTS

Thursday 6 July 2023 09:00

Anne Todgham (University of California Davis, United States)

todgham@ucdavis.edu

Our capacity to predict the effects of anthropogenic change on aquatic ecosystems requires that we consider the complexity of current and future environmental conditions. Single stressor experiments commonly fail to accurately capture the tolerance of species to environmental change as organisms live in complex, multivariate environments. In addition to examining how organisms respond to multiple co-occurring stressors, other aspects of environmental change such as timing and variability may be important components of environmental complexity structuring an organism’s response to change. In this presentation I will speak to issues of environmental complexity by focusing on research in the rocky intertidal, estuarine (and polar environments. Taking an integrative and comparative approach across ontogeny, our research is focused on characterizing the biochemical, physiological and behavioral plasticity of fishes and invertebrates to increases in temperature as well as understanding how co-occurring stressors can interact synergistically to impact performance. Our results provide evidence of stressor-induced energetic trade-offs in physiology and behaviour, with insights on mechanisms from cellular energy metabolism, which may identify physiological weak links leading to vulnerability to future ocean change. I will also highlight different approaches in multiple stressor experiments across research groups to understand unifying themes of responses to complex change. The hope is to initiate discussions of how we, as a research community, can best design multiple stressor experiments that are most relevant to

our species of interest, allowing for comparative analyses of resilience to change, but not too complicated that the additional information doesn’t provide additional predictive power.

A3.31 ULTRAVIOLET RADIATION AND TEMPERATURE IMPACT LARVAL FISH DEVELOPMENT

Thursday 6 July 20233 09:30

Alexis J. Khursigara (University of North Texas, United States), Rachel R. Leads (University of North Texas, United States), Aaron P. Roberts (University of North Texas, United States)

alexis.khursigara@unt.edu

Anthropogenic input of greenhouse gases into the atmosphere has led to an increase in sea surface temperatures. Coping with multiple stressors can exacerbate the negative impacts as the ability to tolerate one stressor can reduce the ability to cope with a secondary stressor. Larval fish are extremely vulnerable to Ultraviolet (UV) radiation due to their lack of pigmentation. Developmental UV radiation has previously been shown to increase metabolic rate, cause morphological deformities, and alter behavior. Rearing temperature greatly influences the rate of development and can lead to differences in the ability to tolerate secondary stressors. To date, few studies have investigated the combined effects of UV and rearing temperature on larval fish, and those that have focused primarily on UV B radiation. The aim of this study was to examine the effects of UV radiation, with a focus on UV A, at different rearing temperatures on the development and performance of larval fish. Following exposures, larvae were assessed for morphological deformities, yolk sac depletion, metabolic rate, and behavior. Based on previous work, we expect to see increases in morphological deformities, yolk sac depletion, and metabolic rate when co-exposed to UV and higher rearing temperatures. These changes could have significant implications for early life stage survival.

A3.32 IMPACT OF ENVIRONMENTAL STRESSORS ON CORAL PHYSIOLOGY: SPATIAL VARIABILITY AND EFFECT OF IRRADIANCE ON PH IN THE CŒLENTE

Thursday 6 July 2023 09:45

Lucas Crovetto (Centre Scientifique de Monaco, Monaco), Alexander Venn (Centre Scientifique de Monaco, Monaco), Duygu Sevilgen (Centre Scientifique de Monaco, Monaco), Sylvie Tambutté (Centre Scientifique de Monaco, Monaco), Eric Tambutté (Centre Scientifique de Monaco, Monaco)

lcrovetto@centrescientifique.mc

Coral reefs, formed by calcium carbonate (CaCO3 ) corals skeleton, are threatened by anthropogenic activity. Stressors such as ocean acidification and rising sea temperatures can adversely affect coral physiology. Corals consist of polyps connected by a tissue, called the cœnosarc, and contain a common fluid-filled internal compartment, the cœlenteron. Symbiotic dinoflagellate-containing cells line the cœlenteron and their photosynthetic activity contributes to changes in the chemistry of the cœlenteric fluid, particularly with respect to pH. Regarding pH in the cœlenteron, no study has yet addressed the

comparison between the cœnosarc and polyps or the influence of light intensity or dinoflagellate density. Therefore, the aim of our study was to fill this gap and determine whether these parameters affect pH in the cœlenteron and could ultimately be affected by environmental stressors. We used the microsensor technique to measure pH in cœlenteron in both polyps and cœnosarc under different light conditions and in different regions of the sample with different dinoflagellate densities to determine the effects of photosynthesis on pH. Our results raise the question of the role of variable pH in the cœlenteron and its impact on mitigating the effects of environmental stressors.

A3.33 RESPONSES OF INTERTIDAL MOLLUSCS TO FLOODING: A MESOCOSM EXPERIMENT TESTING THE COMBINED EXPOSURE TO FRESHWATER, LOW PH AND HIGH TURBIDITY

Thursday 6 July 2023 10:00

Valentine Loiseau (Université du Québec à Rimouski, Canada), Piero Calosi (Université du Québec à Rimouski, Canada), Mathieu Cusson (Université du Québec à Chicoutimi, Canada), Yanick Gendreau (Fisheries and Oceans Canada, Canada)

loim0005@uqar.ca

Estuaries are among the most productive ecosystems, but are extremely vulnerable to local and global changes. Land and river use, changes in precipitation regimes and multiplication of extreme rain events are increasing the frequency and intensity of floods, which induce abrupt changes in estuarian environmental parameters. While estuarian organisms thrive under fluctuating conditions, their responses to intense and prolonged environmental stressors may differ. In addition, the effects of combined stressors (decreased salinity and pH, increased turbidity) encountered during floods on intertidal invertebrates have rarely been studied under laboratory conditions. Consequently, we evaluated the relative sensitivity of three dominant mollusc species found in eastern Canada (Littorina saxatilis, Macoma balthica and Mytilus spp.) to conditions mimicking spring flooding. We measured mortality, shell growth and shell wear of specimens exposed to a gradient of 12 treatments of length of exposure to periodic freshwater injections, with and without acidic and turbid conditions. Threshold analyses showed that mortality was higher in treatments with acidic and turbid conditions, and those with the longest exposure time to freshwater. However, species-specific vulnerability levels were detected. We show that some estuarine species are vulnerable to flooding. These extreme events could therefore be key drivers of biodiversity, species distribution and ecosystem structure and functioning. Our study also confirms the importance of considering combined factors that are representative of natural conditions. Finally, we discuss new critical understandings within the context of improving management strategies to maintain the biodiversity of these environments under global change.

A3.34 PHYSIOLOGICAL RESPONSES OF PACIFIC OYSTER CRASSOSTREA GIGAS TO CLIMATE CHANGE AND OMEGA-3 FATTY ACID SHORTAGE

Thursday 6 July 2023 10:15

Coline Caillon (LEMAR (UBO CNRS IRD Ifremer), France), Elodie Fleury (LEMAR (UBOCNRSIRDIfremer), France), Charlotte Corporeau (LEMAR (UBOCNRSIRDIfremer), France), Carole Di Poi (LEMAR (UBOCNRSIRDIfremer), France), Moussa Diagne (LEMAR (UBOCNRSIRDIfremer), France), Claudie Quere (LEMAR (UBOCNRSIRDIfremer), France), Valerian Le Roy (LEMAR (UBOCNRSIRDIfremer), France), Virgile Quilien (LEMAR (UBOCNRSIRDIfremer), France),

Isabelle Queau (LEMAR (UBOCNRSIRDIfremer), France), Christine Dubreuil (LEMAR (UBOCNRSIRDIfremer), France), Matthias Huber (LEMAR (UBOCNRSIRDIfremer), France), Hugo Koechlin (LEMAR (UBOCNRSIRDIfremer), France), Philippe Soudant (LEMAR (UBOCNRSIRDIfremer), France), Fabrice Pernet (LEMAR (UBOCNRSIRDIfremer), France)

coline.caillon@ifremer.fr

Ocean acidification and warming caused by increased anthropogenic carbon dioxide emissions pose a tremendous challenge to marine calcifiers such as intertidal bivalves. An important, but largely overlooked, consequence of climate change is the reduced availability of dietary omega-3 long-chain polyunsaturated fatty acids (n-3 PUFA) in aquatic food webs. As these multiple drivers occur simultaneously, it is critical to understand their combined effects on marine organisms. Here we investigated the physiological responses of young Pacific oyster Crassostrea gigas exposed for 2 months to current and future (+3°C, -0.3 pH unit) climate scenarios under three diets with different omega-3 contents. We linked up the macro-physiological traits (growth, food intake, reproductive effort, and respiration) of sampled oysters to their biochemical responses (fatty acid composition, and energy reserves). At the end of the experiment, oysters were further challenged with a viral disease to investigate the physiological cost of acclimation. We found that future climate scenario improved growth, ingestion and reproductive output, except when omega-3 content was low. Then, the pathogenic challenge revealed higher risk mortality under future scenario and increasing omega-3, suggesting physiological tradeoffs between growth, reproduction and immune response in oysters. Moreover, increased respiration under future climate scenario and low omega-3 content indicated that oysters increased their energy expenditures to maintain homeostasis under stressful conditions. Overall, this study highlights the need to perform more complex (multi-driver) experiments to explore the sensitivity and plasticity of organisms in a rapidly changing environment.

A3.35 HYPOXIA AND HYPERCAPNIA –AN OVERLOOKED DUO OF MULTISTRESSOR IMPACTS ON FISH?

Thursday 6 July 2023 11:00

Daniel Montgomery (University of British Columbia, Canada) danmont@zoology.ubc.ca

Responses of species to environmental changes will result from the combined effects of multiple individual environmental variables

acting upon physiological performance. While much attention has been focussed on combined effects of warming and elevated CO2 (hypercapnia) or hypoxia (low oxygen) comparatively less work has investigated how combined hypoxia and hypercapnia may affect the physiology of fish. In the majority of cases aquatic hypoxia co-occurs with hypercapnia and so fish that encounter low oxygen conditions will simultaneously experience elevated CO2 levels. On acute time scales hypercapnia can cause respiratory acidosis and reduced oxygen supply capacity as a result of impacts on pH sensitive haemoglobin. But does combined hypoxia and hypercapnia increase the sensitivity of fish to hypoxia? Responses of several species, including European sea bass, European plaice, and European flounder to impacts of environmentally realistic hypercapnia in combination with hypoxia reveal species specific effects on oxygen supply capacity and hypoxia tolerance which are linked to the underlying abilities of each species to regulate acid-base disturbances. As such, physiological mechanisms of species to manage impacts of fluctuating CO2 may also have an important role in determining their hypoxia sensitivity. Overall results to date suggest that physiological performance of fish in hypoxia differs when they are simultaneously exposed to hypercapnia and highlights the need for further research focussing on this overlooked duo of multiple stressors for aquatic organisms

A3.36 EFFECTS OF WARMING RATE ON THE

OF UPPER THERMAL LIMITS IN ZEBRAFISH

Thursday 6 July 2023 11:30

Rasmus Ern (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway)

rasmus@ern.dk

Increases in the frequency and intensity of marine heatwaves and the concurrent expansions of aquatic oxygen-deficient (hypoxic) “dead zones” threaten many fish populations. The oxygen limit for thermal tolerance (PCTmax ) quantifies the water oxygen level at which the critical thermal maximum (CTmax ) becomes oxygendependent and begins to decline with a declining water oxygen level. As such, the PCTmax informs about how fish die-offs during marine heat weaves might be exacerbated by concurrent hypoxic events. Most fish can maintain the highest rates of tissue oxygen supply over relatively short durations, and lower rates of tissue oxygen supply over longer durations. This is important from an experimental perspective because the PCTmax depends on the ability to maintain high rates of tissue oxygen supply and is, therefore, expected to worsen (increase towards normoxia) with decreasing (slower) warming rate. Furthermore, the CTmax of fishes is typically determined using warming rates from degrees per minute to degrees per hour, whereas rises in water temperature during marine heat weaves often occur over days or weeks. Using a wide range of warming rates, we determined the CTmax in zebrafish acutely exposed to water oxygen levels from near-anoxia to hyperoxia and calculated the PCTmax for each warming rate. The results allow us to investigate the relationships between hypoxia tolerance and thermal tolerance under different warming scenarios. This, in turn, may lead to increasingly realistic predictions of how concurrent hypoxic events might exacerbate fish die-offs during marine heat weaves.

Thursday 6 July 2023 11:45

Diana L Silva Garay (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway), Rasmus Ern (Norwegian University of Science and Technology, Norway), Anna H Andreassen (Norwegian University of Science and Technology, Norway), Marie Reiersen (Norwegian University of Science and Technology, Norway)

lorena.silvagaray@gmail.com

There has been much debate about which physiological mechanisms fail first in ectothermic animals during acute warming, particularly about the role of tissue oxygen supply. Here we investigated if the mechanism underpinning warming tolerance changes with acclimation temperature. Specifically, we investigated the effect of temperature acclimation on the oxygen-dependence of warming tolerance in zebrafish (Danio rerio). First, we acclimated zebrafish (N=207) to three temperature groups (20°, 28°, 34°C). For each group, CTmax was determined under acute oxygen exposure (30, 100, 200% air sat). In a second experiment, we examined the aerobic scope and CTmax of cold acclimated zebrafish (20°C, N=113) under a wider spectrum of oxygen manipulation (50, 100, 150, 250% air sat). As expected, hypoxia reduced CTmax across acclimation groups. Interestingly, hyperoxia only increased the CTmax of cold- but not optimally- or warm acclimated zebrafish, showing that oxygen limitation mainly occurs in cold acclimated zebrafish. Furthermore, the improvement of hyperoxia peaked at 150% air sat. The improvement in CTmax from hyperoxia coincided with a dramatically increased aerobic scope, further supporting an oxygen limitation mechanism in cold acclimated fish. We concluded that there is no single mechanism limiting the acute upper thermal tolerance of fish, but likely multiple temperature sensitive physiological functions that may differ between acclimation temperatures.

A3.38 MODERATE REDUCTION IN AMBIENT OXYGEN INCREASES THERMAL SENSITIVITY OF THE SOUTHERN KING CRAB LITHODES SANTOLLA

Thursday 6 July 2023 12:00

Daniela Storch (Alfred-Wegener-Institut Helmholtz-Zentrum für Polar und Meeresforschung, Germany), Rodrigo Lorenzo (Alfred-Wegener-Institut HelmholtzZentrum für Polar- und Meeresforschung, Germany)

Daniela.Storch@awi.de

A rapid global change scenario challenges species biogeographic distribution, especially when it affects their thermal niche, but also other factors can exacerbate changes, such as hypoxia or oxygen minimum zones. We aimed to determine the thermal limits of Lithodes santolla in two dissolved oxygen concentrations (≈20 kPa and ≈12 kPa) in order to study the effect of moderate oxygen variation on the animals’ thermal tolerance by measuring oxygen consumption, heart and ventilation

OXYGEN-DEPENDENCE

A3.37 WARMING TOLERANCE IS OXYGENLIMITED IN COLD-ACCLIMATED BUT NOT WARM-ACCLIMATED ZEBRAFISH (DANIO RERIO)

rates in vivo. L-lactate concentrations in muscle, hemolymph and hepatopancreas as well as glycogen content in the hepatopancreas was determined in vitro. The thermal optimum range was shifted to the cold by 3°C (normoxia: 5.5-16.2°C; reduced oxygen: 3.4-13.4°C) and thermal sensitivity increased at reduced oxygen. Hemolymph lactate was increased under reduced oxygen, which was partly be fueled by glycogen indicated by a decrease of glycogen in the hepatopancreas. Sub-polar species, as the Lithodidae tolerate short term exposure to sub-zero temperatures and were physiological constrained at temperatures > 20 °C. The thermal optimum range determined under acute temperature stress coincides with the temperature regime of the biogeographic distribution from Lithodes santolla. Ongoing deoxygenation of the oceans could decrease the distribution limits of this heavily fished species.

A3.39 THE COMBINED EFFECTS OF TEMPERATURE AND PARASITES ON THE ENERGY METABOLISM OF PUMPKINSEED SUNFISH (LEPOMIS

GIBBOSUS)

Thursday 6 July 2023 12:15

Marie Levet (Université de Montréal, Canada),

Shaun S Killen (University of Glasgow, United Kingdom),

Stefano Bettinazzi (University College London, United Kingdom),

Sophie Breton (Université de Montréal, Canada), Sandra A Binning (Université de Montréal, Canada)

marie.levet@umontreal.ca

Environmental stressors such as elevated temperature and parasite infection can affect individual energy metabolism across levels of biological organization. For example, parasites and temperature can both modify the composition of mitochondrial membranes, leading to a shift in enzymatic activity and a decrease in mitochondria efficiency, ultimately impacting how an individual efficiently converts the metabolic substrate into ATP. This can cause a mismatch between the energy produced and the energy needed to sustain cellular processes. While temperature and parasitism can also be concomitant environmental stressors for ectotherms, their interactive effects on an organism’s metabolism remain unknown. We examined the combined effects of temperature and parasitism on individual energy metabolism at the cellular and whole-organism levels. Wild-caught, naturally parasitized sunfish (Lepomis gibbosus) were acclimated to a temperature treatment (20°c, 25°c, and 30°c) for three weeks. We measured oxygen uptake (ṀO2 ) at their acclimation temperature for 24h using intermittent flow-respirometry. We then measured the enzymatic activities of key organs (brain, spleen, gills and heart) using spectrophotometry. We expect that temperature and parasite infection act synergistically, leading to greater increases in metabolic rates as acclimation temperature and infection load increase. Our work highlights the importance of understanding how combined stressors affect individual physiological performance. Ultimately this work will help us better understand the future consequences of increasing temperature on host-parasite dynamics and fish energetics.

A3.40 WHAT WE MIGHT BE MISSING: BIOTIC AND ABIOTIC FACTORS THAT SHAPE SENSITIVITY TO STRESSORS

Thursday 6 July 2023 14:30

Tamzin Blewett (University of Alberta, Canada)

tamzin@ualberta.ca

Often in experimental studies, controlled environmental conditions follow those stipulated by a specific jurisdiction or regulatory agency conducting assays under fixed and “optimal” exposure scenarios - that may poorly reflect the impact of a toxicant in the natural setting. Abiotic factors such as temperature, dissolved oxygen, salinity, dissolved organic carbon, and the temporal fluctuations (i.e., tide cycle) in these parameters will affect bioavailability of a given toxicant and subsequently toxicity. Similarly, biotic factors including social status, sociality (grouped versus individuals in an exposure), and parasitism will also influence the disposition, impact of a toxicant, and performance of a given species. In this presentation I will examine some of the recent work that has shown how real-world environmental factors alter performance of fish and invertebrate species and how these relationships may be altered by the presence of toxicants. The implications of these findings on ecosystems will also be considered, particularly within the context of global climate change.

A3.41 SEROTONIN UPTAKE BY THE GILL OF

TOADFISH: IMPLICATIONS FOR HYPOXIA TOLERANCE

IN A PHARMACEUTICAL-LACED WORLD

Thursday 6 July 2023 15:00

M. Danielle McDonald (Rosenstiel School of Marine Atmospheric and Earth Science U Miami, United States), James N. Wilson (University of Miami, United States)

dmcdonald@miami.edu

In fish, the neurochemical serotonin (5-HT, 5-hydroxytryptamine) plays a role in the stress response, feeding, oxygen sensing, cardiovascular physiology, reproduction, aggression, and other processes. Work by Ken Olson in the 1990s demonstrated that the gill is a major processing center of 5-HT, removing approximately 80% of the 5-HT from perfusate through a combination of uptake and metabolism. Our objective has been to characterize the role of gill in the control of circulating 5-HT and whether this control has implications on vascular resistance, especially during hypoxia exposure. Our work has shown that uptake of 5-HT by the gill is mediated by multiple monoamine transporters that are the target of anti-depressants, including the 5-HT transporter, and both uptake and degradation of 5-HT by the gill increase when Gulf toadfish, Opsanus beta, are exposed to mild hypoxia. Concurrently, circulating 5-HT concentrations during mild hypoxia exposure decrease and this correlates with a decrease in branchial and systemic blood pressure. Our present work is investigating which gill cells take up 5-HT using confocal microscopy and a fluorescent neurotransmitter probe, 4-(4-(dimethylamino) phenyl)-1-methylpyridinium; APP+)

that moves into cells through monoamine transporters. This work has implications to understanding the risk of combined hypoxia and environmental pharmaceutical exposure.

A3.42 THE TELOMERE ENDOTHERM HEGEMONY: LESSONS FROM ECTOTHERMS

Thursday 6 July 2023 15:15

Rosa Freitas (University of Aveiro, Portugal), Marta Cunha (University of Aveiro, Portugal), Mónica Silva (University of Aveiro, Portugal), Lucia De Marchi (University of Pisa, Italy), Rui Morgado (University of Aveiro, Portugal), Valdemar Esteves (University of Aveiro, Portugal), Valentina Meucci (University of Pisa, Italy), Federica Battaglia (University of Pisa, Italy), Amadeu Soares (University of Aveiro, Portugal), Carlo Pretti (University of Pisa, Italy)

rosafreitas@ua.pt

The impact of pharmaceuticals on marine invertebrates has been a topic of rising concern, with an increasing number of studies regarding the impacts on bivalves. However, very few investigated the toxicity of mixtures of pharmaceuticals. This knowledge gap was investigated in the present study, where the toxicity of 17α-ethinyl estradiol (EE2) and Salicylic acid (SA) mixture was evaluated. To this end,Mytilus galloprovincialismussels were chronically subjected to both pharmaceuticals, acting alone and in combination, and the effects at the cellular level were measured. The Independent Action (IA) model was performed aiming to compare obtained with predicted responses. The integrated biomarker response (IBR) index was used to assess the overall biochemical response given by mussels. The results obtained revealed that the most stressful condition was caused by the combined effect of EE2 and SA, with the highest metabolic capacity, antioxidant (catalase activity) and biotransformation (carboxylesterases activity) activation and cellular damage in organisms exposed to the mixture of both drugs in comparison to responses observed when each drug was acting alone. Predicted responses obtained from the IA model indicate that caution should be paid as frequent deviations to observed responses were found. This study highlights the need for future studies considering the mixture of pollutants, mimicking the actual environmental conditions.

Lénia D. Rato (MARE PLeiria, Portugal), Sara C.

Novais

(MARE Polytechnic of Leiria, Portugal), Tiago Simões (MARE Polytechnic of Leiria, Portugal), Jadilson M. Damasceno (MARE Polytechnic of Leiria, Portugal), David W. Thieltges (NIOZ Texel, Netherlands), Jaap Van der Meer (Wageningen Marine Research Institute, Netherlands), João C. Marques (MARE Coimbra, Portugal), Marco F. L. Lemos (MARE Polytechnic of Leiria, Portugal)

lenia.rato@ipleiria.pt

Besides human-mediated introduction, coastal bioinvasions are influenced by ecosystem disturbance and the plastic capacity of invaders an increasing matter of concern under rapidly changing environments. Irrespective of ecological status, both native and invasive populations face multiple stressors in natura.

The invader Asian shore crabs (Hemigrapsus takanoi and H. sanguineus) established viable and dense populations throughout northern European waters, where detrimental effects were reported on native crab populations (e.g. Carcinus maenas) and bivalve spatthreatening natural stocks and socioeconomic revenue. Hemigrapsus spp. remain unreported in southern European waters reaching higher temperatures: their ecophysiology is fairly unknown, namely under warming or pollution scenarios.

The aim of this project was to investigate the adaptative potential and plasticity of both Carcinus maenas (native) and Hemigrapsus spp. (invader) under: 1) chronic warming, 2) acute and chronic pollution (pesticide), and 3) a bifactorial of acute thermal stress and pollution (pesticide).

The results, assessed through integrative approaches at individual level (behaviour, growth, feed intake or respiration) and sub–individual level (enzymatic and biochemical assays), pinpoint that warmer scenarios may not deter Hemigrapsus expansion. In addition, the native C. maenas was more affected by the exposure to pollution. These findings suggest that Hemigrapsus seem to have higher plasticity under global change scenarios, prompting the native displacement, and expected dominance in the invaded range.

Addressing the impacts of multiple global change drivers is relevant to unravel the underlying mechanisms for bioinvasions’ success and facilitate informed management measures in some of the most worrying topics to environmental sciences and society.

A3.44 DIFFERENCES IN PHENOTYPIC FLEXIBILITY DETERMINE SURVIVAL CHANCES OF TWO FISH SPECIES IN EUTROPHIC WATERS ON A HOT SUMMER DAY

Thursday 6 July 2023 15:45

Thursday 6 July 2023 15:30

April Grace R Opinion (University of Antwerp Department of Biology ECOSPHERE, Belgium), Essie M Rodgers (Murdoch University Harry Butler Institute, Australia), Gudrun De Boeck (University of Antwerp Department of Biology ECOSPHERE, Belgium)

aprilgrace.opinion@uantwerpen.be

Stressors can interact in unanticipated ways, where exposure to one stressor may heighten or reduce the organism’s resilience to another stressor. We examined the interactive effects of nitrate pollution and warming on the physiological performance of a salmonid, the European grayling (Thymallus thymallus), and a cyprinid, the common carp

A3.43 INVASIVE CRABS OUTPERFORMING NATIVES: INTEGRATIVE APPROACHES TO ADDRESS PLASTICITY AND BIOINVASION POTENTIAL UNDER CHANGING ENVIRONMENTS

(Cyprinus carpio). Fishes were exposed to nitrate pollution (0, 50 or 200 mg NO3 − L−1 ) at two acclimation temperatures (18°C and 22°C or 26°C) for up to eight weeks in a 3×2 factorial design. We assessed hypoxia and heat tolerance, aerobic scope (AS, maximum−standard metabolic rates) and cardiorespiratory attributes (haemoglobin HB, haematocrit HCT, relative ventricle mass RVM, and spleen somatic index SSI). In both species, elevated temperature increased AS and the improvement was stronger when coupled with nitrate exposure, which were attributed to the adaptive cardiorespiratory remodelling and haematological fluctuation. Particularly, RVM was higher in warm-exposed T. thymallus and SSI increased in nitrate-exposed fish. In C. carpio, the maintained haemoglobin and increased haematocrit levels which compensated for the initial surge in methaemoblobin at higher nitrate levels contributed to the observed cross-tolerance. Both species also exhibited increased heat tolerance when exposed to warming, but the increase in T. thymallus is higher at higher nitrate levels. While warm-acclimated C. carpio exposed to 200 mg NO3 - L-1 were less susceptible to acute hypoxia, nitrate-exposed T. thymallus, on the other hand, were more susceptible to hypoxia at both temperature due to the nitrate-induced gill histopathological changes that limit oxygen uptake.

A3.45 HOW EXPOSURE TO MULTIPLE STRESSORS ALTERS BEHAVIOR AND HOW

BEHAVIOR ALTERS EXPOSURE TO MULTIPLE STRESSORS

Thursday 6 July 2023 16:30

Amelia Munson (University of Glasgow, United Kingdom), Daphne Cortese (University of Glasgow, United Kingdom), Shaun Killen (University of Glasgow, United Kingdom) amelia.munson@glasgow.ac.uk

Exposure to multiple stressors can demand conflicting responses and the effect of exposure has the potential to be greater than the impact of single stressors combined. While a growing number of studies acknowledge the importance of behavior as first line of defense against exposure to multiple stressors, many studies have focused on simple metrics, like activity, which may miss important consequences. Stress can, for example, alter group dynamics if individuals are differently affected by exposure. I will first discuss how exposure to elevated temperature and hypoxia can alter group level behavioral metrics in fish. Additionally, many multiple stressor studies have failed to consider the nuanced ways in which behavior can alter responses. Lab-based studies often do not give animals an opportunity to leave when exposed to suboptimal conditions even though microhabitats allow animals to alter exposure. This is complicated, however, when groups of animals are considered. If all individuals are avoiding dangerous conditions, and thus using a smaller portion of a habitat, this can increase stress related to competition. Alternatively, group living may be beneficial, but individuals may have different thresholds for stressor avoidance leading to conflicting demands for group space use. Here I will discuss research using a large flume and a series of RFID readers to understand how groups of common minnowsPhoxinus phoxinusbalance conflicting demands from exposure to elevated temperature.

A3.46 MULTIPLE LOCAL- TO GLOBALSCALE STRESSORS INFLUENCE THE PERFORMANCE AND MANAGEMENT OF THREATENED AQUATIC ORGANISMS

Thursday 6 July 2023 17:00

Sue-Ann Watson (Queensland Museum James Cook University, Australia)

sueann.watson@jcu.edu.au

Aquatic organisms are subject to a range of environmental stressors and can have limited ability to move to avoid stressful conditions, particularly if they are site-attached. Giant clams are the world’s largest bivalve molluscs and are essentially sessile past the larval stage. Threatened by overexploitation for human consumption, their valuable shells and the aquarium trade, these iconic megafauna are extinct in some former areas of their global range. Consequently, giant clam species are included in the IUCN Red List of Threatened Species and are CITES-listed. Now, giant clams are threatened additionally by rapid environmental change from both local- to regional-scale stressors, such declining water quality and pollution, and global change stressors, including ocean warming and acidification. This presentation will show how multiple local- to global-scale drivers (including light availability, ocean warming and ocean acidification) are likely to cause an array of effects on survival, physiology, performance and behaviour, potentially limiting giant clam depth distribution on coral reefs and decreasing suitable habitat area within natural ranges. Enhanced knowledge of ecological and physiological responses to multiple stressors could play a critical role in the conservation of threatened species through rapid environmental change. Further work on how biological responses translate into habitat requirements as global change progresses, selective breeding for resilience, the capacity for rapid adaptive responses of the giant clam holobiont, and enhancing tourism potential may help improve the prospects of these charismatic megafauna over coming decades.

A3.47 INTERACTING STRESSORS ALONG ENVIRONMENTAL GRADIENTS: EFFECT OF NUTRIENT ENRICHMENT AND SALINITY VARIATION ON AN ESTUARINE ECOSYSTEM.

Thursday 6 July 2023 17:15

Charlotte Carrier-Belleau (Laval University, Canada), Scott Tiegs (Oakland University, United States), Christian Nozais (Université du Québec à Rimouski, Canada), Philippe Archambault (Laval University, Canada)

charlotte.carrier-belleau.1@ulaval.ca

Anthropogenic impacts and global changes have profound implications for natural ecosystems and may lead to their modification, degradation or collapse. Increases in the intensity of single stressors may lead to ecological thresholds, which can create abrupt shifts in biotic responses. The effects of multiple interacting stressors may create synergistic or antagonistic interactions, leading to non-linear responses. Here we combine both concepts – ecological thresholds and interactions between multiple stressors – to understand the effects of multiple interacting stressors along environmental gradients, and how

this can affect the occurrence of thresholds. Using an experimental approach to investigate the effect of nutrient enrichment and saltwater intrusion on mortality in the zebra mussel, Dreissena polymorpha, we show that multiple stressors can create thresholds at lower levels of an environmental gradient. Our results reveal that by treating the concepts of ecological thresholds and multiple stressors individually we risk underestimating widespread anthropogenic impacts. Our results reveal a major shortcoming in how we currently investigate these two ecological concepts, as considering them separately may be causing underestimation of thresholds and stressor-interaction impacts.

A3.48 EFFECTS OF FOOD QUANTITY AND DIETARY FAT QUALITY ON THERMAL PLASTICITY AND TOLERANCE OF A MARINE FISH (OPALEYE; GIRELLA NIGRICANS)

Thursday 6 July 2023 17:30

Emily Hardison (University of California Santa Barbara, United States), Eileen Schauerman (University of California Santa Barbara, United States), Madeleine Yung (University of California Santa Barbara, United States), Erika Eliason (University of California Santa Barbara, United States)

emilyhardison@ucsb.edu

Food provides the energy and nutrients animals need to physiologically respond to environmental stressors, meaning that changes in nutrition could profoundly impact animal performance and environmental tolerance. Here, we tested the influence of two aspects of nutrition that are expected to differ in response to anthropogenic change (food quantity and dietary fat quality) on the thermal performance of a temperate fish (opaleye; Girella nigricans). As marine fish gain most of their energy from fats, they must balance assimilating them into tissues against metabolizing them to meet their metabolic demand. Their capacity to maintain an optimal balance between the two may be impaired by reductions in food, declines in essential nutrients, and co-occurring environmental stressors, such as rising temperatures. We assessed the impacts of changes in the amount of food, along with the amount of omega-3 fatty acids in the diet, on opaleye metabolism and thermal tolerance after acclimation to two environmentally relevant temperatures (presumed optimal: 15°C and climate-change scenario: 22°C). Interestingly, dietary fat quality had a greater impact on opaleye performance when the fish were fed less across both temperatures. Specifically, diets low in omega-3 fatty acids conferred higher aerobic scope but led to lower upper thermal limits. Ration size was also an important determinant of cardiac performance, where fish fed high ration diets had higher maximum heart rates across temperatures. These results demonstrate how important it is to consider diet when evaluating ectotherm responses to climate change, as diet quality and quantity can interactively affect thermal plasticity and tolerance.

A3.49 DIRECTIONAL SELECTION ACTS IN SYNERGY WITH THERMAL STRESS TO REDUCE DNA PROTECTION MECHANISMS

Thursday 6 July 2023 17:45

Daniel E Sadler (University of Jyväskylä, Finland), Stephan Van Dijk (University of Jyväskylä, Finland), Phillip C Watts (University of Jyväskylä, Finland), Silva Uusi-Heikkilä (University of Jyväskylä, Finland)

daniel.e.sadler@jyu.fi

Overfishing is one of the biggest threats to aquatic ecosystems. High mortality rates and distinct size selectivity can cause evolutionary changes and reduce genetic diversity in exploited populations. Consequently, fished populations may have low adaptive potential hampering their capability to cope with other anthropogenic stressors occurring simultaneously. Telomere length and rDNA copy number can be used as indicators of stress with enhanced stress causing shortening of telomeres and decreased rDNA copy number. Here, we utilise three populations exposed to size-selective harvesting: large-selected (removing 75% of the smallest individuals from the population, leaving the largest individuals), small-selected (removing 75% of largest individuals from the population, leaving the smallest individuals, mimicking fisheries), and random-selected (removing 75% of a population randomly). Five generations of size-selective harvesting induced numerous phenotypic changes in exploited populations together with large-scale genetic changes. To assess the performance of size-selectively exploited fish populations under thermal stress, we exposed individuals to three temperature treatments (34°C; 28°C; 22°C). We assessed differences among the selection lines in telomere length, rDNA copy number and mtDNA copy number. We found that telomere length and rDNA copy number decreased when temperature increased in the size-selected populations but remained stable across all temperatures in the random-selected line. In contrast mtDNA copy number remained relatively stable across temperature treatments suggesting greater resilience to stress. These results increase our understanding of synergistic stressors on fish populations under fisheries and future climatic scenarios.

A4 MECHANICS OF MECHANORECEPTION ACROSS SCALES AND KINGDOMS

ORGANISED BY: BRIAN DANIEL SALTIN (UNIVERSITY OF BONN), THOMAS R. NEIL (UNIVERSITY OF BRISTOL)

A4.1 USING ROBOTIC MODELS OF ANIMALS TO BETTER UNDERSTAND PROPRIOCEPTION AT NON-INERTIAL SCALES

Thursday 6 July 2023 14:30

Nicholas S. Szczecinski (West Virginia University, United States), Clarus A. Goldsmith (West Virginia University, United States), William P. Zyhowski (West Virginia University, United States), Gesa F. Dinges (West Virginia University, United States), Sasha N. Zill (Marshall University, United States)

nss00001@mail.wvu.edu

Insects are highly mobile walkers who adapt their muscle output to their ever-changing environment. Force sensors in their legs called campaniform sensilla (CS) detect increasing and decreasing forces, which may help insects coordinate their legs as they walk and compensate for external forces, for example, when walking on inclined or uneven surfaces. Our work investigates the mechanical and neural dynamics of CS that enable them to detect changes in force and proposes hypotheses regarding how these dynamics affect nervous system activity.

To this end, we have constructed multiple dynamically scaled robotic models of insects and their legs. Each robot has leg kinematics (e.g., joint axes, segment lengths) that correspond to the species it mimics. Robot movements are slowed to reduce the magnitude of inertial forces the same as in insect legs. Strain gauges are mounted on the leg segments in species-specific locations and orientations. As the robotic leg steps, the strains of the exoskeleton are recorded. These strains are fed through a model of CS sensory discharge, which was developed based on extracellular recordings of afferent nerves. The model output is a plausible discharge pattern that the nervous system would experience in response to the forces generated during locomotion. This technique has highlighted CS’ ability to detect critical events during walking (e.g., the beginning of stance, the end of stance, foot slipping); enabled the comparison of strains experienced by different insects with different CS arrangements; and emphasized the importance of force dynamics for load sensing and control.

A4.2 FUNCTIONAL MORPHOLOGY AND ANATOMY OF THE MECHANOSENSORY FEMORAL CHORDOTONAL ORGANS IN INSECT LEGS

Thursday 6 July 2023 15:00

Simran Virdi (National Centre for Biological Sciences Tata Institute of Fundamental Research, India), Sanjay P. Sane (National Centre for Biological Sciences Tata Institute of Fundamental Research, India) simran.virdi21@gmail.com

In addition to being the main organs for walking, insect legs provide mechanosensory feedback about the substrates which they walk on. Mechanical stimuli from substrates activate mechanosensory organs called femoral chordotonal organs (FeCO), which are housed in the leg. These stimuli are first filtered by the mechanics of associated structures, and then processed by the encoding neurons. Although the neural filtering of sensory signals is well-studied, we know relatively little about the mechanical pre-filtering. To address this, we investigated the structure of the femoral chordotonal organ (FeCO) in insect legs to understand its mechanics. FeCO is involved in sensori-motor integration of legs during walking and posture maintenance, and senses tibial movements relative to femur. Tibial flexion stretches the organ and extension relaxes it. We characterized FeCO in the Oleander hawkmoth Daphnis nerii using microCT and confocal microscopy. FeCO is located proximally within the femur and connected to tibia via a rigid rod-like structure called an apodeme. Rotational motion of the tibia is converted into translational motion of apodeme in a linear fashion, causing the organ to stretch during flexion. FeCO contains two subunits with 8 neurons in one and ~88 neurons in the other. We aim to understand how these subunits are functionally organized in moths and what is the underlying biomechanical basis for this functional segregation within the organ. These data enable a better understanding of how the structure of a mechanosensor affects its sensory physiology.

A4.3 BIOMIMETIC STRAIN SENSORS HIGHLIGHT THE RELEVANCE OF ARRANGEMENT FOR LOAD SENSING

Thursday 6 July 2023 15:15

Gesa F Dinges (West Virginia University, United States), Willam P. Zyhowski (West Virginia University, United States), Nicholas S. Szczecinski (West Virginia University, United States)

gfd00004@mail.wvu.edu

Insects achieve adaptable locomotion through limb sensory organs that monitor motor output. Sensory organs called campaniform sensilla (CS) are found grouped on the legs of Drosophila melanogaster. Their location within the cuticle enables them to encode highly dynamic strains.To better understand the relevance of sensor locations for motor networks, we have used nano-computed tomography (nanoCT) segmentation to 3D print a mechanical model of the ventral femoral CS field. This field possesses elliptical CS with varying axes orientations as well as circular CS. We created further models based on the original with artificial changes, such as rotations of the whole field or individual CS. All models were printed from resins whose Young’s moduli mimic those of cuticular components. To test how these morphologies may affect strain measurements, we used a tensile tester to apply tensile force that mimics strains experienced by a fly leg during movement. The directional strain of each cap location was measured by foil strain gauges. Preliminary results indicate that the resin models simulate the same hysteresis observed in electrophysiological and mechanical CS experiments. This feature enables us to monitor the applied force in a physiologically plausible manner. The nanoCT-based model shows a distal to proximal compression gradient during tensile force application, as well as varying sensitivities in different sensor locations. Understanding biomechanical and neurobiological connections in the context of species-specific biomechanics requires interdisciplinary experimental approaches. By connecting accessible engineering techniques with high-resolution imaging, we aim to contribute to the biological understanding of load sensing.

A4.4 SUBSTRATE-BORNE VIBRATIONS AS AN INFORMATION SOURCE: FROM SPIDERS TO ELEPHANTS

Thursday 6 July 2023 16:30

Thomas E Miller (University of Oxford, United Kingdom), Jun Wu (University of Oxford, United Kingdom), Beth Mortimer (University of Oxford, United Kingdom)

thomas.miller@biology.ox.ac.uk

Substrate-borne vibrations are a ubiquitous source of information throughout the animal kingdom, being used by the smallest arthropods to the largest land mammals for biological functions. A universal problem with sensing is how to filter information from noise, which is a particular issue for vibration sensing given the heterogeneity of the materials that vibrations pass through. For small arthropods, extracting information from noise is challenging since small variations in morphological parameters will affect sensing dynamics through the legs. For larger organisms, the increasing environmental influences on vibration sensing when information is

transferred over larger scales is more significant. Spiders are the ideal model organism in which to investigate the robustness of vibration sensing dynamics – particularly web-building spiders, which possess an additional level of control through the extended phenotype of the web. For this, we use laser vibrometry to produce non-contact velocity recordings of the spider’s response to vibrational input, enabling us to examine the dynamics of vibration transmission in an untethered live animal in its natural posture. At the other end of the size spectrum, we study elephants that are thought to transfer vibrational information over the kilometre scale. Here, seismic playback has proved to be a vital tool for probing the behavioural significance of seismic stimuli to elephants and the conservation implications of anthropogenic seismic noise. Together, these studies show that both body and substrate play an important role in information filtering, and the relative importance of each of these factors is likely to change with scale.

A4.5 MECHANOPERCEPTION IN MIMOSA PUDICA INVOLVES THE ACTIVITY OF MECHANOSENSITIVE ION CHANNELS

Thursday 6 July 2023 17:00

Anja Geitmann (McGill University, Canada), Daniel Tran (McGill University, Canada), Hugues Petitjean (McGill University, Canada), Youssef Chebli (McGill University, Canada), Reza Sharif-Naeini (McGill University, Canada)

geitmann.aes@mcgill.ca

Mechanoperception, the ability to respond to mechanical stimuli, is a common and fundamental property of all forms of life. Some vascular plants such as Mimosa pudica use this function to protect themselves against herbivory. The mechanical stimulus caused by a landing insect triggers a rapid closing of the leaflets that drives the potential pest away. While this thigmonastic movement is caused by ion fluxes accompanied by a rapid change of volume in the pulvini, the mechanism responsible for the detection of the mechanical stimulus remains poorly understood. Here, we examined the role of mechanosensitive ion channels in the first step of this evolutionaryconserved defense mechanism: the mechanically evoked closing of the leaflet. To identify the sensitive regions within the Mimosa leaf, we used van Frey filaments to apply calibrated forces to specific regions on the leaflets. Our results demonstrate that the key site of mechanosensation in the Mimosa leaflets is the pulvinule, which expresses a stretch-activated chloride-permeable mechanosensitive ion channel. Blocking these channels partially prevents the closure of the leaflets following mechanical stimulation. Through patch-clamp we characterized the ion channels' behavior. The results demonstrate a direct relation between the activity of mechanosensitive ion channels and a central defense mechanism of the Mimosa pudica.

A4.6 POSITION AND VELOCITY ENCODING BY MECHANOSENSORY JOHNSTON’S ORGAN IN HAWKMOTHS.

Thursday 6 July 2023 17:30

Chinmayee L Mukunda (National Centre for Biological Sciences, India), Sanjay P Sane (National Centre for Biological Sciences, India)

chinmayeelm@gmail.com

Insect antennae are extremely important multisensory probes. In addition to being primary olfactory organs, antennae sense a vast array of mechanical stimuli ranging from gravity, airflow, touch and antennal vibrations that are essential for behaviours ranging from foraging and escape to routine navigation. Mechanosensory feedback is especially crucial in nocturnal flying insects because visual feedback is slow under low light levels, and not sufficient to enable stable flight. Previous experiments have shown that, in nocturnal moths, stable flight requires feedback about antennal vibrations, and these stimuli are encoded by the antennal Johnston’s organs (JO) situated at the base of the long passive flagellum segment of the antennae. JO consists of several scolopidial units that are individually narrowly tuned, but together encode a wide frequency range of the antennal vibrations that inform the insect about their own flight status. In this study, we investigate both the static and dynamic encoding properties of the Johnston’s organ in the Oleander hawkmoth, Daphnis nerii. We performed intracellular recordings from scolopidial axons while stimulating the JO with various stimuli, including constant position, constant velocity, and white noise stimuli. Our data reveal scolopidial units that encode velocity and position in their phasic and tonic responses, respectively. Some scolopidial units exhibit linear encoding of velocity of the stimulus. From the responses to white noise stimuli, we identified the specific stimulus features encoded by the sensory units. Together, these data reveal some of the encoding strategies of the JO that may be essential for flight control.

A4.7 BUZZ POLLINATION AS A MECHANICAL INTERACTION BETWEEN PLANTS AND BEES

Friday 7 July 2023 12:00

Mario Vallejo-Marin (Uppsala University, Sweden)

mario.vallejo-marin@ebc.uu.se

Buzz pollination is a specialised interaction that involves half of all bee species and more than 20,000 species of flowering plants. During buzz pollination, a bee applies vibrations to specialised pollen-carrying structures (anthers) on flowers to rapidly remove large numbers of pollen grains. The vibrations, produced with their powerful thoracic muscles, cause the pollen grains inside tube-like anthers to eject, peppering the body of the bee with thousands of pollen grains. The bee then collects these pollen grains and uses them as the main source of protein to feed their developing larvae. The physical interaction between the bee and flower during buzz pollination is mainly a mechanical one. Vibrations produced in the bee’s thorax are transmitted by direct contact to the anthers and other floral structures causing them to shake and resulting in pollen ejection. Therefore, mechanical properties of both bees and flowers are fundamental to mediate the outcome of buzz pollination. Here I will talk about

the biomechanical properties of buzz-pollinated flowers and their relationship with floral morphology and reproductive strategy. I will then discuss the mechanical characteristics of vibrations produced by bees across behavioural contexts. Finally, I will present new results on the estimated forces that diverse types of bees, from Mexico to Australia, can produce, and discuss what this means for buzz pollination.

A4.8 ROLE OF PROPRIOCEPTION IN THE OCTOPUS ARM MOVEMENTS

Friday 7 July 2023 12:30

Letizia Zullo (IRCCS Ospedale Policlinico San Martino, Italy), Janina L Rockner (ISTITUTO ITALIANO DI TECNOLOGIA, Italy), Beatrice Pistolato (ISTITUTO ITALIANO DI TECNOLOGIA, Italy)

letizia.zullo1@gmail.com

Octopus arms are capable of complex motions that are used in a wide repertoire of behaviors. These complex movements can be produced by a combination of four basic deformations: elongation, shortening, bending and torsion. Deformation like bending and torsion can occur in an isolated arm in response to external tactile stimulation and stretch. They are mediated through sensory receptors of suckers and skin and possibly also proprioceptive receptors of muscles mostly located within the four arm intramuscular nerve cord (INC).

Physiological experiments suggested that uniquely to the octopus arm, feedback from proprioceptors can be an integral part of the peripheral neuronal circuitry that contribute to structuring whole-arm movement.

In this work we investigated the presence, type, and functional role of muscle proprioceptive receptors in octopus arms. With proteomic investigations, we found evidence for the presence of piezo mechanosensitive ion channels in the arm musculature and in the suckers and investigated their localization across the arm. With neural tracing technique we marked the connection between the INC and the arm peripheral nervous system (the axial nerve cord, ANC). We next used a preparation of muscle/ANC to identify the amount and type of information passing from the muscle undergoing stretch to the ANC and possibly implemented in the arm peripheral motor programs.

This study represent the first assessment of muscle proprioception function at a lower level control of arm motion and open the way to further investigate its role in central control of motion.

A4.9 ON THE AUDITORY MECHANICS OF THE MICROSCALE KATYDID EAR

Friday 7 July 2023 12:45

Emine Celiker (University of Dundee, United Kingdom), Charlie Woodrow (University of Lincoln, United Kingdom), Fernando Montealegre-Z (University of Lincoln, United Kingdom)

eceliker@dundee.ac.uk

Katydids (bush-crickets) have sophisticated tympanal ears located in the tibia of their forelegs. Like mammals, katydid ears also contain outer-, middle- and inner-ear components. Through the outer-ear the tympana receive a dual sound input: an input to the internal side from the tracheal tube, the acoustic trachea, and an input to the external side directly. While the acoustic trachea acts as the mammalian ear-canal, our understanding of the mechanism behind the differing resonance properties of the tubes between species is limited. The inner-ear of katydids are generally likened to an uncoiled mammalian cochlea, containing an easily accessible hearing organ, the crista acustica (CA). The CA is made up of mechanosensory receptors along a structure with varying stiffness, which are activated through the frequency dependent displacement of the structure. This displacement is generally ascribed to the gradual stiffness and mass changes along the hearing organ, although the biomechanism behind it merits further investigation.

In this talk, I will present an overview of our numerical investigation of the katydid auditory mechanics. In particular, we introduce a new mechanism behind the resonance properties of the acoustic trachea of species Pterodichopetala cieloi (Phaneropterinae). Further, I will present our progress on the investigation of the inner-ear workings of Copiphora gorgonensis (Tettigoniidae) through finite element analysis, which suggests that even the mildest assumptions about stiffness gradients allow for frequency dependent displacements of the hearing organ. The simulations are based on the real 3D geometries of the ear from micro-CT tomography and are validated through experimental data.

A5 INSECT OSMOREGULATION

ORGANISED BY: HEATH MACMILLAN (CARLETON UNIVERSITY), JULIAN DOW (UNIVERSITY OF GLASGOW), KENNETH HALBERG (UNIVERSITY OF COPENHAGEN)

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A5.1 WATER DEPRIVATION ALTERS METABOLIC STRATEGY INTRIBOLIUM CASTANEUM: UNIQUE MECHANISM FOR WATER PRODUCTION REGULATED UNDER AKH HORMONES

Wednesday 5 July 2023 POSTER SESSION

Muhammad Tayyib Naseem (University of Copenhagen, Denmark), U. Saeed (University of Copenhagen, Denmark), D.W. Rana (University of Copenhagen, Denmark), K.V. Halberg (University of Copenhagen, Denmark)

muhammad.naseem@bio.ku.dk

Insects are known to maintain water balance by regulating water intake and excretion through a complex process known as osmoregulation. Remarkably, some insects, like the red flour beetleTribolium castaneum, can complete their entire life cycle without access to environmental water and still maintain systemic water balance. However, the physiological mechanisms that enable them to replace the water invariably lost to the environment remain incompletely understood. Here, we perform a large-scale functional screen by sequentially knocking down all genes encoding a neuropeptide or biogenic amine and assessed their impact on desiccation tolerance inTribolium. Surprisingly, these data show that adipokinetic hormones (AKHs), a group of neuropeptides that play crucial roles in regulating lipid and carbohydrate metabolism, were among the genes that enhance desiccation tolerance the most. Gravimetric analysis of whole animal water content show thatAkh/AKHRdepleted animals maintain body fluid balance better than controls. Further, thecorpora cardiacaautonomously respond to high haemolymph osmolality by releasing AKH into circulation, while acute injection of AKH analogues correlates with higher body water during desiccation relative to controls. Taken together, our work identifies AKH signalling as a novel key regulator of water balance inTriboliumand show that metabolic water is physiologically relevant to species living in xeric environments. Understanding the complex interplay between AKH signalling and other hormonal circuits could provide insights into the mechanisms involved in the regulation of energy and water balance in insects and potentially lead to the development of novel pest control strategies.

A5.2 SUBDUED LIMITS BACTERIAL INVASION AND CALCIUM OXALATE CRYSTAL FORMATION IN DROSOPHILA MALPIGHIAN TUBULES

Wednesday 5 July 2023 POSTER SESSION

Orestes Foresto-Neto (Mayo Clinic College of Medicine Science Rochester MN, United States), Daniel R. Turin (Mayo Clinic College of Medicine Science Rochester MN, United States), Heather L. Holmes (Mayo Clinic College of Medicine Science Rochester MN, United States), Carmen J. Reynolds (Mayo Clinic College of Medicine Science Rochester MN, United States), Mariah L. Arneson (Mayo Clinic College of Medicine Science Rochester MN, United States), Pablo Cabrero (University of Glasgow Glasgow, United Kingdom), Muthuvel Jayachandran (Mayo Clinic College of Medicine Science Rochester MN, United States), Julian A.T. Dow (University of Glasgow Glasgow, United Kingdom), John C. Lieske (Mayo Clinic College of Medicine Science Rochester MN, United States), Eva Furrow (University of Minnesota St. Paul MN, United States), Michael F. Romero (Mayo Clinic College of Medicine Science Rochester MN, United States)

ForestoNeto.Orestes@mayo.edu

Calcium oxalate (CaOx) crystallization is increased when uropathogenic E. coli (UPEC) is transurethrally inoculated in mice. Anoctamin 4 (ANO4) protein in urinary extracellular vesicles is decreased in human CaOx stone formers. In Drosophila Malpighian tubules (MT), subdued (ANO4-homolog) plays a role in host defense against bacteria. We used Drosophila to investigate whether subdued changes CaOx crystallization and if crystallization is altered by UPEC.

C724:Gal4 or Uro:Gal4 flies were crossed with UAS:subdued-RNAi flies to knockdown (KD) subdued in MT stellate cells (SC) or principal cells (PC), respectively. F1 generation underwent CaOx crystallization in association or not with UPEC. Ex vivo, dissected MTs were submerged in a solution containing 10mM NaOx+UPEC:eGFP for 90min. In vivo, flies were fed a diet supplemented with 20mM NaOx+UPEC:eGFP for 4d.

Subdued-KD of SC slightly increased bacterial infection but did not change ex vivo or in vivo crystallization. Subdued-KD of PC increased the presence of UPEC and number of crystals in MTs during ex vivo assays. Neither crystal number nor size were changed by subdued-KD of PC after prolonged NaOx feeding in vivo. However, when UPEC were introduced with the NaOx diet, subdued-KD flies exhibited a large bacterial presence in MT lumen and enlarged CaOx crystals compared to wild type flies were observed.

Drosophila is a genetic model to study bacterial infection and oxalosis. The presence of subdued in Drosophila MT PCs reduces CaOx crystallization via reduced uropathogenic bacterial infection. Our data suggest a role for ANO4 in bacterial-related human lithiases. (U54DK100227, R01-DK092408, FAPESP 2022/01226-1, Mayo Foundation)

A5.3 INVESTIGATING THE ROLES OF GAP JUNCTION PROTEINS AND NOVEL GENES IN RENAL FUNCTION

Wednesday 5 July 2023

POSTER SESSION

Xueying Bai (School of Molecular Biosciences University of Glasgow, United Kingdom), Sue Krause (School of Molecular Biosciences University of Glasgow, United Kingdom), Anthony Dornan (School of Molecular Biosciences University of Glasgow, United Kingdom), Shireen Davies (University of Glasgow, United Kingdom), Julian Dow (School of Molecular Biosciences University of Glasgow, United Kingdom)

x.bai.1@research.gla.ac.uk

Metabolism plays an important role in the survival of all animals. Equivalent to the kidneys, which are an excretory organ in vertebrates, the excretory organ in insects is the Malpighian tubules. With the development of genomics and genetics related to Drosophila, the Malpighian tubules have become a model system for studies on the metabolism process, ion transport, fluid secretion and osmoregulation mechanisms. To explore these functions, the gap junctions in the tubules are involved in this project. Two specific genes (Innexin 2 and Innexin 7) that are highly expressed in the tubules are knocked down in an attempt to answer the question of whether gap junctions are important to epithelial function. With the development of the sequencing technologies of the Drosophila genome, FlyCellAtlas is used as a single-cell sequencing technique to detect specific gene information in whole adult flies at the single-cell level. Moreover, proteins and metabolites are also quantified by metabolomics, analysing the functions of the new gene (CG6602) in terms of renal function. Transcriptomics can also be used in this project to localise and analyse CG6602. Lastly, this project explores the function of Octalpha2R in the tubules, as well as studies the effect on other biogenic amines.

A5.4 PREMATURE RENAL AGEING IS TRIGGERED BY COMPROMISED JUNCTIONAL INTEGRITY IN DROSOPHILA SNAKESKIN MUTANTS

Wednesday 5 July 2023

POSTER SESSION

Anthony J Dornan (University of Glasgow, United Kingdom), Kenneth V Halberg (University of Copenhagen, Denmark), Liesa-Kristin Beuter (Justus-Liebig-University Giessen, Germany), Shireen-Anne Davies (University of Glasgow, United Kingdom), Julian A T Dow (University of Glasgow, United Kingdom)

anthony.dornan@glasgow.ac.uk

Transporting epithelia provide a protective barrier against pathogenic insults while allowing the controlled exchange of ions, solutes and water with the external environment. In invertebrates, these functions depend on formation and maintenance of ‘tight’ septate junctions (SJs). However, the mechanism by which SJs affect transport competence and tissue homeostasis, and how these are modulated by ageing, remain incompletely understood. Here, we demonstrate that the Drosophila renal (Malpighian) tubules undergo an age-dependent decline in secretory capacity, which correlates with mislocalisation of SJ proteins and progressive degeneration in cellular morphology and tissue homeostasis. Acute loss of the septate junction protein Snakeskin

in adult tubules induces progressive changes in cellular and tissue architecture, including altered expression and localisation of junctional proteins with concomitant loss of cell polarity and barrier integrity, demonstrating that compromised junctional integrity is sufficient to replicate these ageing-related phenotypes. Taken together, our work demonstrates a crucial link between epithelial barrier integrity, tubule transport competence, renal homeostasis and organismal viability, as well as providing novel insights into the mechanisms underpinning age-onset and renal disease.

A5.5 WFLYMET.ORG: EXPLORING THE DROSOPHILA METABOLOMIC TISSUE ATLAS

Wednesday 5 July 2023 POSTER SESSION

Sue A Krause (University of Glasgow, United Kingdom), Karen McLuskey (University of Glasgow, United Kingdom), Shireen Davies (University of Glasgow, United Kingdom), Karl Burgess (University of Edinburgh, United Kingdom), Ronan Daly (University of Glasgow, United Kingdom), Julian Dow (University of Glasgow, United Kingdom)

sue.krause@glasgow.ac.uk

An organism’s metabolome contains all the compounds that are produced by its metabolism. In all multicellular organisms the metabolomes of different tissues are likely to differ significantly, reflecting the specialized jobs they perform. This has the potential to provide a dynamic view of tissue cell function.

Using Drosophila melanogasteras a model, we have produced an atlas of 20 different reference tissue metabolomes, obtained by separate micro-dissection of adult (male and female) and larvalDrosophila. Using liquid-chromatography mass spectrometry (LC-MS), a snapshot of each tissue’s metabolome was taken in the form of LC-MS peaks. To present this complex data, we have developed FlyMet (www.flymet. org): A database and web application that provides user-friendly visualization of metabolite profiles across Drosophila tissues. Users can confidently investigate comprehensive tissue data as peaks, metabolites, or pathways and metabolomic data can be easily linked to transcriptomic data.

As a FlyMet use-case, we investigated enriched metabolomic differences between Drosophila tubules and the other tissues, including the whole animal. This led to investigations into the brown eye pigmentation (ommochrome) pathway and the discovery that the tubules work as a storage system for eye-pigment precursors. Pairing the metabolomics data with transcriptomic data we also found that metabolites are transferred between several tissues along the pathway. Tissue metabolomics paired with transcriptomics gives a dynamic insight into metabolic processes and allows functionality of genes and tissues to be explored. FlyMet allows easy access to these large Drosophila data sets and the user-friendly exploration of genes, metabolites, and metabolic pathways of interest.

A5.6 THE CELL ADHESION MOLECULE FASCICLIN3 IS REQUIRED FOR THE EPITHELIAL FUNCTION OF MALPIGHIAN TUBULES IN DROSOPHILA MELANOGASTER

Wednesday 5 July 2023

POSTER SESSION

Keqin Li (School of Molecular Biosciences University of Glasgow, United Kingdom), Shireen A Davies (School of Molecular Biosciences University of Glasgow, United Kingdom), Julian A Dow (School of Molecular Biosciences University of Glasgow, United Kingdom)

2579635L@student.gla.ac.uk

Epithelial dysfunction in the kidney causes various human diseases, like hypervolemia and nephrolithiasis. The Malpighian tubule, a functional analog of the human kidney, has long been a model system for the study of epithelial function (doi:10.1038/s41581-022-00561-4). Genomewide association (GWA) studies using Drosophila melanogaster Genetic Reference Panel (DGRP) lines (doi:10.1038/nature10811) have been widely used for identifying candidate causal genes affecting quantitative traits (doi:10.1002/wdev.289). To find novel genes involved in epithelial function, a GWA study for fluid secretion was carried out using the DGRP lines. One candidate is the gene Fasciclin3 (Fas3), which encodes a cell adhesion molecule. Knockdown of Fas3 in principal cells causes enlarged abdomens with lower fluid secretion rates and increased body water content, which are consistent with longer desiccation survival. Moreover, the absence of Fas3 promotes the proliferation of renal stem cells and the development of kidney stones. In Fas3 RNAi flies, septate junction protein Discs large staining is also compromised. Because of the loss of cytoarchitectural organisation, Fas3 inhibition in stellate cells alters the number and morphology of stellate cells in an age-related manner. Tubules with impaired stellate cells do not secrete at a high rate in response to the stimulation of neuropeptide kinin. These findings imply that Fas3 is necessary for normal renal epithelial function and that the GWA study can identify genetic variations associated with fluid secretion rates.

A5.7 MULTI-OMICS OF INSECT OSMOREGULATION

Wednesday 5 July 2023

POSTER SESSION

Julian A.T. Dow (UNIVERSITY OF GLASGOW, United Kingdom),

Sue A Krause (University of Glasgow, United Kingdom),

Karen McLuskey (University of Glasgow, United Kingdom),

Mehwish Akram (University of Glasgow, United Kingdom),

Andrew Gillen (University of Glasgow, United Kingdom),

Anthony J Dornan (University of Glasgow, United Kingdom),

Xueying Bao (University of Glasgow, United Kingdom), Keqin Li (University of Glasgow, United Kingdom), Shireen A Davies (University of Glasgow, United Kingdom)

julian.dow@glasgow.ac.uk

Insect Malpighian tubules generate primary urine and excrete waste, and so perform a renal function. However, they play multiple additional roles in metabolism, detoxification and innate immunity. Our understanding of insect renal function has been accelerated by the experimental taming of the Drosophila melanogaster tubule, allowing physiology and genetics to be combined in the same system. Additionally, the insights gained from the post-genomic technologies (transcriptomics, proteomics and metabolomics) have transformed our understanding. Here, we will briefly survey past successes, and outline plans to improve our understanding of Malpighian tubule functions across the insects, and of epithelial function in general.

A5.8 CROSS-TALK BETWEEN DRICE AND SERCA REGULATES DEVELOPMENT AND FUNCTION OF MALPIGHIAN TUBULES OF DROSOPHILA MELANOGASTER

Thursday 6 July 2023 09:00

Madhu G Tapadia (Banaras Hindu Unvieristy, India) madhu@bhu.ac.in

The fate of cells to die or not to die is dependent upon the enzymatic activation of executioner caspase Drice, aDrosophilahomolog of mammalian caspase-3. Activation of Drice is a non-reversible process, and the cells are eliminated by apoptosis. Apart from its role in apoptosis, Drice is non-apoptotically essential for the development of Malpighian tubules in a certain manner. Homozygous deletion or null Drice allele, the Malpighian tubules lose their architecture, assume a grossly misshaped fluid filled cystic phenotype, and increased uric acid deposition. In the present paper, we show calcium signaling to be an important regulator of MTs development and function. Inhibiting Sarco Endoplasmic reticulum calcium ATPase (SERCA) genetically as well as by chemical feeding restores the mutant phenotype. We will be presenting data on our hypothesis to show that SERCA could be regulating the function of RhoGTPase, yorkie and c-Myc in Drice homozygous mutant background.

A5.9 THE BEETLE CRYPTONEPHRIDIAL COMPLEX: REPLUMBING THE INTERNAL BODY PLAN OF AN INSECT THROUGH MULTI-ORGAN FGF CROSSTALK

Thursday 6 July 2023 09:30

Barry Denholm (University of Edinburgh, United Kingdom) barry.denholm@ed.ac.uk

The beetle cryptonephridial complex (CNC) makes key contributions to the water budget in a vast number of species by recovering water from the rectum and recycling it back to the body. It is even used by some species to harvest water from the atmosphere. The complex has evolved by a radical reorganisation of internal anatomy: the rectum and Malpighian (renal) tubules are brought into close apposition in counter current configuration, and are isolated within a chamber by a unique tissue of unusual structure and unknown origin—the perinephric membrane. The arrangement of these features with respect to one another are essential for CNC function, yet the mechanisms underpinning its construction are unknown. In this talk I’ll chart the development and molecular signals that drive the reorganisation of the beetle’s internal anatomy during the construction of the CNC for the model beetle Tribolium. I will show how a dynamic and intricately woven crosstalk between the rectum, Malpighian tubule and perinephric membrane precursor cells through Fibroblast Growth Factor (FGF) signalling establish the counter current configuration and close apposition of the rectum with Malpighian tubule, as well as the recruitment and elaboration of the perinephric membrane. I will also consider the origin and nature of the perinephric membrane and its position as an evolutionarily novel tissue. In sum, our work reveals how the insect internal body plan has been reconfigured in beetles to construct one of the most powerful water-conserving system in nature, one

that is fundamental to the physiology, ecology and evolution of many insects.

A5.10 SERCA INHIBITION REPAIRS THE MORPHOLOGICAL AND FUNCTIONAL DEFECTS CAUSED BY DRICE MUTATION IN MALPIGHIAN TUBULES OF DROSOPHILA MELANOGASTER

Thursday 6 July 2023 10:00

Chandan Kumar Maurya (Banaras Hindu University, India), Madhu G Tapadia (Banaras Hindu University, India)

chandank.maurya10@bhu.ac.in

Polycystic kidney disease, caused by uric acid deposition in excretory tubule epithelial cells, has become a common cause of chronic kidney injury. Increased uric acid levels are the strongest predictor of biochemical and metabolic abnormalities, influencing cellular signaling, including calcium signaling within the cell. A decrease in initiator Caspase-3, effector DCP-1, and the absence of Drice drive uric aciddeposition, irregular distribution, and local thickening of cytoskeletal actin and cadherin proteins. In our study, we found that inhibiting SERCA (Sarco-Endoplasmic Reticulum Calcium ATPase) reduces uric acid deposition and restores tissue phenotype by regulating cell calcium and downstream signaling like JNK, AKT, MAPK, RAS, Relish, and Yorkie. Inhibition of SERCA increases the expression of HSP-70, PERK, and Na+ - K+ ATPase and thereby restores the tubular length by increasing the cell number and the number of PH3 positive cells. This study provides new insight for SERCA dependent mechanism to regulate and repair the tubular phenotype and ameliorate the uric acid deposition from Malpighian tubules in Drosophila melanogaster.

A5.11 NHA1 IS A CATION/PROTON ANTIPORTER ESSENTIAL FOR THE WATER-CONSERVING FUNCTIONS OF THE RECTAL COMPLEX IN TRIBOLIUM CASTANEUM

Thursday 6 July 2023 10:15

Kenneth V. Halberg (University of Copenhagen, Denmark), Muhammad T. Naseem (University of Copenhagen, Denmark), Robin Beaven (University of Edinbrugh, United Kingdom), Takashi Koyama (University of Copenhagen, Denmark), Sehrish Naz (University of Copenhagen, Denmark), Shengyuan Su (University of Edinbrugh, United Kingdom), David P. Leader (University of Glasgow, United Kingdom), Dan A. Klaerke (University of Copenhagen, Denmark), Kirstine Calloe (University of Copenhagen, Denmark), Barry Denholm (University of Edinbrugh, United Kingdom)

kahalberg@bio.ku.dk

More than half of all extant metazoan species on earth are insects. The evolutionary success of insects is linked with their ability to osmoregulate, suggesting that they have evolved unique physiological mechanisms to maintain water balance. In beetles (Coleoptera)—the largest group of insects—a specialized rectal (‘cryptonephridial’)

complex has evolved that recovers water from the rectum destined for excretion and recycles it back to the body. However, the molecular mechanisms underpinning the remarkable water-conserving functions of this system are unknown. Here, we introduce a transcriptomic resource, BeetleAtlas.org, for the exceptionally desiccation tolerant red flour beetle Tribolium castaneum, and demonstrate its utility by identifying a cation/H+ antiporter (NHA1) that is enriched and functionally significant in the Tribolium rectal complex. NHA1 localizes exclusively to a specialized cell type, the leptophragmata, in the distal region of the Malpighian tubules associated with the rectal complex. Computational modelling and electrophysiological characterization in Xenopus oocytes show that NHA1 acts as an electroneutral K+ / H+ antiporter. Furthermore, genetic silencing of Nha1 dramatically increases excretory water loss and reduces organismal survival during desiccation stress, implying that NHA1 activity is essential for maintaining systemic water balance. Finally, we show that Tiptop, a conserved transcription factor, regulates NHA1 expression in leptophragmata and controls leptophragmata maturation, illuminating the developmental mechanism that establishes the functions of this cell. Together, our work provides the first insights into the molecular architecture underpinning the function of one most powerful waterconserving mechanisms in nature, the beetle rectal complex.

A5.12 TRANSEPITHELIAL OXALATE TRANSPORT IN DROSOPHILA MALPIGHIAN TUBULES – AN AVATAR TO STUDY KIDNEY STONES AND INFECTION

Thursday 6 July 2023 11:00

Michael F. Romero (Mayo Foundation for Medical Education and Research, United States), Orestes Foresto-Neto (Mayo Foundation for Medical Education and Research, United States), Daniel R. Turin (Mayo Foundation for Medical Education and Research, United States), Heather L. Holmes (Mayo Foundation for Medical Education and Research, United States), Carmen J. Reynolds (Mayo Foundation for Medical Education and Research, United States), Jacob B. Anderson (Mayo Foundation for Medical Education and Research, United States), Mariah L. Arneson (Mayo Foundation for Medical Education and Research, United States), Pablo Cabrero (University of Glasgow, United Kingdom), Kenneth Halberg (University of Glasgow, United Kingdom), Muthuvel Jayachandran (Mayo Foundation for Medical Education and Research, United States), Adam J. Rossano (Mayo Foundation for Medical Education and Research, United States), Julian A.T. Dow (University of Glasgow, United Kingdom), John C. Lieske (Mayo Foundation for Medical Education and Research, United States), Eva Furrow (University of Minnesota, United States)

Romero.Michael@mayo.edu

Calcium oxalate (CaOx) crystals form in DrosophilaMalpighian tubules (MT) when NaOx supplements food, or MTs are bathed with NaOx. This fly avatar of kidney stones allows testing of both apical and basolateral transporters and channels in this transepithelial transport process. Early studies found that the apical Drosophilaprestin (Slc26a6 ortholog) mediates Cl- /Ox2- exchange. We have tested membrane proteins and signaling molecules in principle cells (PC) and stellate cells. At the apical membrane, OSR1 (fray) kinase controls dPrestin activity. An apical Zip10-like transporter (CG10006) transports Zn2+ (complexing with CaOx) to form larger crystals. The ClC-5 homology Clc-c is apical and allows us to model Dent disease type 1 (DD1) as

the proteins have similar electrogenic function and conserved residues mutated in DD1 cases. We also hypothesize that apical AQPs in both PC (Eglp2) and SC (Drip) limit CaOx crystal formation by moving water into the MT lumen.

At the basolateral membrane, a Sat1 (Slc26a1) homolog exchanges HCO3 ??' for Ox2- or SO4 2- using a genetically encoded pH-sensor. This HCO3 ??' mediated Ox2- uptake implies that the basolateral NDAE1 protein may be another control on this process. Similarly, basolateral AQPs (Eglp4 in PC; Prip in SC) should contribute to transepithelial water movement controlling crystallization.

Finally, we can model the role of bacterial infection in CaOx kidney stones usingsubdued, the anoctamin 4 (ANO4) in PCs. As ANO4 is associated with CaOx stones in dogs and humans, the fly avatar reveals that this may be due to specifically renal infection.

A5.13 SALT, WATER AND UREA: ROLE OF THE BESTROPHIN-1 CHLORIDE CHANNEL IN THE DROSOPHILA MELANOGASTER RESPONSE TO HIGH SALT DIET

Thursday 6 July 2023 11:30

Aylin R Rodan (University of Utah, United States), John M Pleinis (University of Utah, United States), Sima Jonusaite (University of Utah, United States), Katherine Beebe (University of Utah, United States), Daryl E Morrison (University of Utah, United States), Forest Streeter (University of Utah, United States), Jacob Hudac (University of Utah, United States), Austin Goodwin (University of Utah, United States), Ashlee Roberts (University of Utah, United States), Jeffrey N Schellinger (University of Utah, United States), Adrian Rothenfluh (University of Utah, United States)

aylin.rodan@hsc.utah.edu

The mechanisms allowing Drosophila melanogaster to tolerate a highsalt diet are incompletely understood. We fed flies a control diet with or without 0.3M NaCl. Flies with a germline loss-of-function mutation in the chloride channel, bestrophin-1 (best1c04106 ) had increased lethality on high salt diet. best1c04106 mutants have impaired transepithelial ion and fluid fluxes in the Malpighian tubule. Control flies fed high-salt diet overnight had increased hemolymph osmolality, which was lower in best1c04106 mutants. Control flies became dehydrated after overnight high salt feeding. best1c04106 mutants had normal body water content when fed normal diet, but became more dehydrated than controls on high salt and exhibited higher lethality when water-deprived. best1c04106 mutant phenotypes were rescued by a genomic rescue construct, or by expression of wildtype best1 in the Malpighian tubules and rectal pads. Hemolymph metabolomic analysis revealed that urea was the most upregulated solute in controls fed high salt, whereas best1 mutants failed to increase urea. Feeding best1c04106 mutants high salt supplemented with 50 mM urea normalized hemolymph osmolality compared to controls fed high salt, prevented the excess dehydration of the mutants, and rescued lethality. Feeding best1c04106 mutant flies the urea precursor, arginine, also partially rescued lethality on high salt diet, whereas feeding another amino acid, proline, did not. In conclusion, flies with impaired Malpighian tubule and hindgut ion transport function due to loss of the bestrophin-1 chloride channel have impaired ability to tolerate high salt diet, with lower hemolymph osmolality, failure to increase hemolymph urea concentration, increased dehydration, and death.

A5.14 VOLTAGE-GATED ION CHANNELS AS NOVEL REGULATORS OF ION TRANSPORT IN INSECT EPITHELIA

Thursday 6 July 2023 11:45

Dennis Kolosov (California State University San Marcos, United States)

dkolosov@csusm.edu

Animals rarely live in environments that match their internal levels of ions and water. Epithelia are multifunctional tissues that simultaneously serve as both, a barrier to unwanted diffusion and as a conduit for active transport, helping animals move ions, water, nutrients, and wastes in and out of their bodies. Epithelial ion transport is adjusted depending on the needs of the animal, maintaining salt and water balance in the face of environmental and systemic challenges (e.g., when an animal ingests a meal or enter an environment of different salinity). Recent studies have demonstrated that epithelia of many animals express a variety of voltage-gated ion channels (VGICs). This includes voltagegated Ca2+ , Na+ , K+ and cation-selective ion channels. In our lab at California State University San Marcos,we study how VGICs regulate ion transport in animal epithelia using insect and fish model organisms. To date, we have demonstrated that several VGICs are expressed in and regulate ion transport in insect epithelia. Why do non- innervated non-contractile epithelia need VGICs? Whereas VGICs are integral to the function of excitable tissues like nerves and muscles, their function in epithelia remains largely understudied and unknown to date. Using a combination of transcriptomics, molecular biology, microscopy, electrophysiology, and pharmacology we aim to: (i) characterize VGIC ensembles in epithelia of vertebrates and invertebrates, and (ii) provide insight into how they regulate ion transport.

A5.15 MOLECULAR PHYSIOLOGY OF TRANSEPITHELIAL CATION TRANSPORT MECHANISMS IN MOSQUITO MALPIGHIAN TUBULES

Thursday 6 July 2023 12:00

Peter M Piermarini (The Ohio State University, United States), Chris M Gillen (Kenyon College, United States)

piermarini.1@osu.edu

Malpighian tubules play critical roles in various physiological processes, including salt and water balance, xenobiotic detoxification, and nitrogenous waste excretion. Essential to nearly all of these processes is transepithelial fluid secretion, which generates a primary urine compartment for the deposition of excess ions, water, and metabolic wastes from the hemolymph. Transepithelial fluid secretion is of especial importance to mosquitoes, which encounter unique challenges to water balance associated with their amphibious life cycle and the hematophagy of adult females. The Malpighian tubules of mosquitoes secrete fluid via a two-step process; i.e., cations (primarily Na+ and K+ ) and anions (primarily Cl- ) are transported from the hemolymph to the tubule lumen, which then generates a favorable osmotic gradient for water to follow. Here we provide an update on our understanding of molecular mechanisms involved with transepithelial cation transport in mosquito Malpighian tubules. We will focus on new insights into the functional and regulatory properties of inward rectifier K+ (Kir)

channels and cation chloride cotransporters (CCCs) that are expressed in mosquito Malpighian tubules. We will discuss how these mechanisms may contribute to transepithelial fluid secretion in mosquito Malpighian tubules as well as elements of the mosquito life cycle.

A5.16 RHODNIUS PROLIXUS MALPIGHIAN TUBULES; DIURESIS AND SO MUCH MORE.

Thursday 6 July 2023 14:30

Ian Orchard (University of Toronto Mississauga, Canada), Angela B Lange (University of Toronto Mississauga, Canada)

ian.orchard@utoronto.ca

Rhodnius prolixus, a major vector of Chagas disease, may be considered the model upon which the foundations of insect physiology and biochemistry were built. It is an obligate blood feeder in which the blood meal triggers growth, development and reproduction. The blood meal, which can be 10 times the initial mass of the insect, also triggers a post-prandial diuresis within minutes of the start of gorging; lowering the mass and concentrating the nutrients of the meal. Thus, R. prolixus rapidly excretes a fluid that is high in NaCl content and hypo-osmotic to the haemolymph. In R. prolixus, as with other insects, the Malpighian tubules play a critical role in diuresis, and their fine control comes under the influence of the neuroendocrine system that releases diuretic or antidiuretic hormones. These hormones act upon the Malpighian tubules via a variety of G protein-coupled receptors linked to second messenger systems that influence ion transporters and aquaporins. Much has been learned about diuresis in R. prolixus, and in other model insects. The post-genomic era, however, has brought new insights, identifying novel diuretic and antidiuretic hormone-signaling pathways but also identifying functions quite apart from diuresis for Malpighian tubules, including immunity and detoxification. In addition, though, hormones controlling diuresis and released at gorging may also be involved in coordinating aspects of egg production in the adult which is also triggered by gorging. This paper will review the neuroendocrinological control of diuresis in R. prolixus, but also consider diuresis and Malpighian tubules in a broader physiological context.

A5.17 NEUROENDOCRINE CONTROL OF HYDROMINERAL BALANCE IN ADULT MOSQUITOES

Thursday 6 July 2023 15:00

Jean-Paul Paluzzi (Department of Biology York University, Canada), Farwa Sajadi (Department of Biology York University, Canada) paluzzi@yorku.ca

Similar to other insects, secretion by mosquito Malpighian tubules (MTs) is driven by the apically localized V-type H+ -ATPase (VA) in principal cells. CAPA is a mosquito anti-diuretic neurohormone that inhibits select diuretic hormones; however, the cellular effectors of this inhibitory signaling cascade remain unclear. Like CAPA, the VA inhibitor bafilomycin selectively inhibits diuretic hormones, including the calcitonin-related diuretic hormone (DH31 ). VA activity increases in DH31 -treated MTs, whereas CAPA abolishes this increase via the NOS/

cGMP/PKG signaling pathway. A key feature of VA activation involves the reversible association of its cytosolic (V1) and membrane (Vo) complexes. Interestingly, higher V1 protein abundance was observed in membrane fractions of DH31 -treated MTs while CAPA decreased V1 abundance in membrane fractions. Further, V1 complex was strictly immunolocalized to the apical membrane in DH31 -treated MTs whereas CAPA treatment led to a dispersed staining. Complementing this data from in vitro experiments, we examined immunolocalization of VA complexes and measured hormone titres of CAPA and DH31 in bloodfed female mosquitoes. VA complexes colocalized apically in female MTs shortly after blood-feeding correlating with highest DH31 levels quantified in the haemolymph. Comparatively, V1 immunolocalization was dispersed and did not colocalize apically with the Vo complex in the MTs a few hours following blood-feeding, a timepoint when DH31 levels are lowest and CAPA levels are elevated in the haemolymph. Collectively, these findings reveal neurohormonal fine-tuning of the MTs to match the immediate demands of the insect that range from rapid fluid and ion elimination or their conservation as necessary for achieving homeostasis.

A5.18 PEPTIDERGIC PATHWAYS MODULATING OSMOTIC HOMEOSTASIS IN DROSOPHILA

Thursday 6 July 2023 15:15

Meet Zandawala (Julius-Maximilians-University of Würzburg, Germany)

meet.zandawala@uni-wuerzburg.de

Environmental factors challenge the physiological homeostasis in animals, thereby evoking stress. Neuropeptides are the main signaling molecules that help maintain this homeostasis. Several neuropeptides have previously been shown to regulate water balance in insects. But how multiple peptidergic signaling pathways interact to orchestrate organismal behavior and physiology under different contexts (e.g., normal vs desiccated) are poorly understood. Moreover, resolving the spatial and temporal dynamics of peptidergic signaling (what are the targets of neuropeptides, when are they modulated and for how long?) has also been challenging due to a lack of tools to observe neuromodulatory activity in-vivo. Here, we use the power of Drosophila genetics to address this knowledge-gap. We have developed a powerful genetic tool, TANGO-Map MkII, to analyze hormonal signaling in Drosophila in-vivo. We showcase the power of this technique by utilizing TANGO-Map MkII sensors to visualize modulation of tissues associated with osmotic regulation (the Malpighian tubules and gut) under diverse contexts that challenge osmotic homeostasis. We combine TANGO-Map MkII with transcriptomics, fly genetics and molecular, cellular and physiological methods to decipher the neuropeptidergic pathways that orchestrate osmoregulation. Our approach sets the framework to understand how multiple peptidgergic pathways interact to regulate other aspects of organismal physiology.

A5.19 G PROTEIN-COUPLED RECEPTORS FOR KININS, PYROKININS AND PERIVISCEROKININS IN HARD TICKS AND MOSQUITOES

Thursday 6 July 2023 15:45

Patricia V. Pietrantonio (Texas AM University, United States) p-pietrantonio@tamu.edu

Our research focuses on GPCRs for arthropod-specific pleiotropic neuropeptides involved or potentially involved in osmoregulationkinins, periviscerokinins and pyrokinins. Our goal is to investigate organismal and tissue physiology by both reverse-genetics and pharmacological approaches. The research focuses on the yellow fever mosquito, Aedes aegypti, and the cattle fever tick (southern cattle tick, Asian blue tick), Rhipicephalus microplus. These species are vectors of deadly pathogens causative of human or animal diseases, respectively. The global problem of pesticide resistance in their populations threatens control of disease transmission. Utilizing recombinant receptor expression in CHO-K1 cells, we investigated the pharmacology of kinin neuropeptide GPCRs in a comparative approach testing endogenous ligands, peptidomimetics, and by developing a ‘dual-addition’ high-throughput screening fluorescence method for discovery of small molecule ligands. Such small synthetic molecules are useful as chemically stable physiological probes and as potential leads for novel pesticides or synergists. In vitro assays with tick and mosquito tissues evaluated the function of all such ligand types; and for tick tissues assays were performed with the brown dog tick, R. sanguineus, and the blacklegged tick, Ixodes scapularis. Furthermore, as feeding and osmoregulation are directly linked in blood-feeders, we investigated the contribution of specific receptors to overall fitness through RNAi of kinin, periviscerokinin, and pyrokinin receptors in tick females. Verification of RNAi phenotypes and qRT-PCR results support the involvement of these receptors in tick female feeding and reproductive fitness.

prevents age-associated fibrosis, which we predict will reflect how age interacts with Malpighian tubule osmoregulation and endocrine function.

A5.21 A UNIQUE MALPIGHIAN TUBULE ARCHITECTURE IN TRIBOLIUM CASTANEUM INFORMS THE EVOLUTIONARY ORIGINS OF SYSTEMICOSMOREGULATION IN BEETLES

Thursday 6 July 2023 17:00

Takashi Koyama (University of Copenhagen, Denmark), Muhammad T Naseem (University of Copenhagen, Denmark), Dennis Kolosov (McMaster University, Canada), Camilla T Vo (University of Copenhagen, Denmark), Duncan Mahon (University of Copenhagen, Denmark), Amanda S. S. Jakobsen (University of Copenhagen, Denmark), Rasmus L Jensen (University of Copenhagen, Denmark), Barry Denholm (University of Edinburgh, United Kingdom), Michael O’Donnell (McMaster University, Canada), Kenneth V Halberg (University of Copenhagen, Denmark) takashi.koyama@bio.ku.dk

A5.20

SYSTEMIC IMMUNITY AND FIBROSIS REGULATED BY DROSOPHILA MALPIGHIAN TUBULE ENDOCRINE SIGNALING

Thursday 6 July 2023 16:30

Marc Tatar (Brown University, United States)

marc_tatar@brown.edu States)

The Malpighian tubules of adult Drosophila provide a stress and agingassociated endocrine function. They produce and secrete the steroid ecdysone from stellate cells in response to transient desiccation and as a function of age. This ecdysone modulates several homeostatic responses in female and male adults. In a paracrine fashion, renal ecdysone primes and amplifies the expression of antimicrobial peptides (AMPs) that are produced in the Malpighian tubules. As a consequence, water-stressed adults have elevated AMP expression and are resistant to bacterial infection. While innate immune expression and ecdysone signaling typically increase with fly age, these processes are reduced by high humidity, which likewise increases lifespan. In the course of aging, adult ecdysone produced by the Malpighian tubules also modulates the accumulation of extracellular matrix pericardin (a collagen) at the heart and its associated nephrocytes. Cardio-nephrocyte fibrosis reduces nephrocyte filtration and produces a proteinuria-like phenotype. Remarkably, excess pericardin originates from cardiomyocytes through the action of ecdysone with the G-protein coupled receptor dopEcR, and not by 20HE with the canonical nuclear hormone receptor EcR. Cardiac-nephrocyte fibrosis increases in the normal course of Drosophila aging, in parallel with elevated ecdysone synthesis from the Malpighian tubules. Systemic blockade of ecdysone synthesis in aging adults

Maintaining internal salt and water balance in response to fluctuating external conditions is essential for animal survival. This is particularly true for insects as their high surface-to-volume ratio makes them highly susceptible to osmotic stress. However, the cellular and hormonal mechanisms that mediate the systemic control of osmotic homeostasis in beetles (Coleoptera), the largest group of insects, remain largely unidentified. Here, we demonstrate that eight neurons in the brain of the red flour beetle Tribolium castaneum respond to internal changes in osmolality by releasing diuretic hormone (DH) 37 and DH47—homologs of vertebrate corticotropin-releasing factor (CRF) hormones—to control systemic water balance. Knockdown of the gene encoding the two hormones (Urinate, Urn8) reduces Malpighian tubule secretion and restricts organismal fluid loss, whereas injection of DH37 or DH47 reverses these phenotypes. We further identify a CRF-like receptor, Urinate receptor (Urn8R), which is exclusively expressed in a functionally unique secondary cell in the beetle tubules, as underlying this response. Activation of Urn8R increases K+ secretion, creating a lumen-positive transepithelial potential that drives fluid secretion. Together, these data show that beetle Malpighian tubules operate by a fundamentally different mechanism than those of other insects. Finally, we adopt a fluorescent labeling strategy to identify the evolutionary origin of this unusual tubule architecture, revealing that it evolved in the last common ancestor of the higher beetle families. Our work thus uncovers an important homeostatic program that is key to maintaining osmotic control in beetles, which evolved parallel to the radiation of the “advanced” beetle lineages.

Andrew Donini (York University, Canada),

Sima Jonusaite (York University, Canada),

Alrishia Agard (York University, Canada),

Farah Hashemi-Sabet (York University, Canada),

Helen Chasiotis (York University, Canada), Scott P Kelly (York University, Canada)

adonini@yorku.ca

Sodium chloride (NaCl) applied as rock salt or a brine on surfaces in winter easily dissolves in water and contaminates nearby freshwater systems. More recently organic de-icers have been discovered and are being applied in conjunction with NaCl. Freshwater animals and plants are threatened by sudden and often extreme influxes of salt after winter storms and over the years salt has been accumulating in freshwater leading to an overall increase in salt levels. Here we report on the effects of NaCl and an organic based de-icer on the functions of the iono- and osmoregulatory organs of chironomid larvae. Exposure to NaCl or organic de-icer causes an increase in hemolymph Na+ , and Na+ and K+ , respectively. Exposure to NaCl does not affect the function of primary urine-generating Malpighian tubules but exposure to organic de-icer increases tubule fluid secretion rate and [K+ ] of secreted fluid. The anal papillae, which are the sites of ion uptake from the external environment, switch from taking up sodium in freshwater to excreting it when the larvae are exposed to de-icers. We also carried out organ-specific expression of genes encoding paracellular barrier forming septate junction (SJ) components and found high transcript abundances in the midgut, tubules, and anal papillae. Furthermore, exposure to organic de-icer led to the upregulation of SJ transcripts in the midgut, whereas organic de-icer and NaCl resulted in reduced SJ transcript abundance in the hindgut and anal papillae. Overall, organic de-icer alters osmoregulatory physiology of chironomid larvae to an even greater extent than NaCl.

A5.23 CHARACTERIZATION OF THE ION TRANSPORT PEPTIDE SIGNALING SYSTEM IN DROSOPHILA

Thursday 6 July 2023 17:30

Jayati Gera (Julius-Maximilians-University Würzburg, Germany), Farwa Sajad (York University, Canada), Marishia Agard (York University, Canada), Francesca McEwan (Stockholm University, Sweden), Dick Nässel (Stockholm University, Sweden), Jean-Paul Paluzzi (York University, Canada), Meet Zandawala (Julius-Maximilians-University Würzburg, Germany)

jayati.gera@uni-wuerzburg.de

Insects have evolved a variety of neurohormones that enable them to maintain their osmotic and ionic homeostasis. While the identities and functions of various insect diuretic hormones have been wellestablished, characterization of an anti-diuretic signaling system that is conserved across most insects is still lacking. To address this, here we characterize the ion transport peptide (ITP) signaling system inDrosophila. TheDrosophilaITPgene encodes five transcript variants which generate three different isoforms: ITPa, ITPL1 and ITPL2. We use a combination of GAL4 lines, antibody staining and single-cell transcriptomics to map the expression of all three ITP isoforms in the nervous system and peripheral tissues. Immunohistochemical analysis indicates that ITP is released into the hemolymph during desiccation. Moreover, recombinantDrosophilaITP can inhibit renal tubule secretionin vitro, thus confirming its role as an anti-diuretic

hormone. We have also identified and characterized the elusive ITP receptor (ITPR) inDrosophila. Extensive anatomical mapping of ITPR using a newly-generated GAL4 line reveals that it is broadly expressed in larval and adultDrosophila. Importantly, ITPR is expressed in tubules and the rectal pads, tissues that are associated with insect osmo/ionoregulation. Consistent with this expression, tubule-specific knockdown of ITPR abolishes the decreased secretion rates observed following application of recombinant ITP. Lastly, insect ITP and crustacean hyperglycemic hormone are evolutionary related and we further show the involvement ofDrosophilaITP in regulating metabolic homeostasis. Taken together, our comprehensive characterization of the ITP signaling system inDrosophilasets the stage to uncover anti-diuretic signaling mechanisms in insects.

A5.24 ION REGULATORY CAPACITY AT LOW TEMPERATURE DETERMINES INSECT COLD TOLERANCE

Friday 7 July 2023 09:00

Johannes Overgaard (Aarhus University, Denmark) johannes.overgaard@bio.au.dk

Cold tolerance is one of the most important factors dictating the distribution of insect species. For most insects the central challenge with low temperature is to balance active and passive transport at temperatures where the capacity for active transport is thermodynamically constrained. Using data comparing cold tolerant and cold sensitive Drosophila species, I will discuss this central physiological challenge at both the organismal and cellular level. At the organismal level, cold injury is associated with loss of extracellular ion homeostasis which is normally regulated by the Malpighian tubules and hindgut. In accordance, cold adaptation and cold acclimation is associated with physiological modifications to transport capacity in both Malpighian tubules and hindgut that help to maintain homeostasis. At the cellular level, cold exposure cause cellular depolarisation due to loss of ion balance and decreased electrogenic ion-pumping. This loss of membrane polarization is directly associated with onset of cold coma and cellular injury. These examples of organismal and cellular cold adaptation highlight how homeostatic regulation of active and passive ion-fluxes is at the core of cold tolerance physiology of insects.

A5.25 ON THE LOSS OF CENTRAL NERVOUS FUNCTION IN INSECTS AND ITS RELATION TO ION BALANCE REGULATION

Friday 7 July 2023 09:30

Mads K Andersen (Carleton University, Canada), R. Mel Robertson (Queen's University, Canada), Heath A MacMillan (Carleton University, Canada)

mads.andersen@carleton.ca

When exposed to abiotic stress, insects experience performance deficits that often manifest as a loss of coordinated movement followed by the onset of an unresponsive, coma-like phenotype. This loss of function has been attributed to a loss of central nervous function caused by a spreading depolarization (SD) event, which is triggered by an inability

to maintain brain ion homeostasis. This results in a rapid surge in extracellular K+ concentration which silences central integrating neurons. However, this limit to neural function is plastic, and most insects are capable of altering the threshold for SD via acclimation. The mechanisms underlying variation in the SD threshold, however, remain largely unknown. The regulators of central nervous system ion homeostasis are numerous, but key components include Na+ channels, K+ channels, and the Na+ /K+ -ATPase. Thus, it seems likely that the disruption of one or more of these regulators leads to SD and by extension that variation in channel or pump function underlies variation in the SD threshold. Using a comparative model system of cold- and warm-acclimated fruit flies (Drosophila melanogaster) my recent work has sought to investigate, directly and indirectly, the potential roles of K+ channels and the Na+ /K+ -ATPase in altering the threshold for SD. In this talk, I will synthesize the findings from a range if electrophysiological, pharmacological, molecular, and genetic knock-down experiments designed to investigate the function and thermal sensitivity of these important regulators of ion balance within the nervous system.

A5.26 RESPIROMETRY REVEALS MAJOR DIFFERENCES IN THE ENERGETIC RESPONSES OF FRESHWATER INVERTEBRATES TO SALINITY

Friday 7 July 20233 09:45

Subhash Rajpurohit (Ahmedabad University, India)

subhash.rajpurohit@ahduni.edu.in

Insects are susceptible to dehydration due to their large surface-tovolume ratio. Environmental changes in humidity and temperature could affect insect fitness and sustained water loss could be fatal. We performed a series of experiments to explore desiccation tolerance in an out-crossed Drosophila melanogaster population. The first set of experiments was carried out in three outdoor mesocosm cages in which D. melanogaster populations were tracked over 90 days. Fecundity was checked for throughout the 90-day period, by collecting eggs daily from both indoor and outdoor cages. Fecundity was affected by the interaction of both temperature and relative humidity. This work suggested that ‘temperature-humidity’ interactions affect the physiological state of an organism which could ultimately impact organismal fitness. Additionally, cages were also sampled for whole genome sequencing analysis. Interestingly, candidates involved in kinases and phosphorylation emerged as key players. We also analyzed the reproductive behavior of flies at varying body water levels. Our results showed that the duration of desiccation was positively correlated with mating latency and mating failure while having no influence on the copulation duration. Metabolomic analysis revealed three biological pathways highly affected by desiccation: starch and sucrose metabolism, galactose metabolism, and phenylalanine, tyrosine, and tryptophan biosynthesis. These results are consistent with carbohydrate metabolism providing an energy source in desiccated flies, suggesting that the phenylalanine biosynthesis pathway plays a role in the reproductive fitness of the flies. Recent climate changes should sound alarm bells for insect decline and conservation.

david_buchwalter@ncsu.edu

All freshwater organisms are challenged to control their internal balance of water and ions in strongly hypotonic environments. However, the relationships between salinity, ion transport rates and oxygen consumption (MO2 ) remain poorly understood across species. Existing data are rare and generally indicate that higher MO2 rates are associated with lower salinities. These observations indicate a greater energetic cost of offsetting diffusive ionic losses in progressively dilute situations. Here, we measured the influence of external salinity on the MO2 of three species of aquatic insects, one snail, and one crustacean. Consistent with available literature, we show a clear decrease in MO2 with increasing salinity in the snail (Elimia sp.) (r=-0.99, p=0.03) and crustacean (Gammarus pulex) (r=-0.99, p=0.05). However, we show here for the first time that metabolic rates are unchanged by salinity in aquatic insects, while ion transport rates are positively correlated with higher salinities. In contrast, when we examined the ionic influx rates of Ca and Na in G. pulex, we found that Ca uptake rates were highest under the most dilute conditions, while Na uptake rates increased with salinity. This finding potentially implicates the cost of calcium uptake as a driver of increased metabolic rate in G. pulex under dilute conditions and suggests phyletic differences in osmoregulatory physiology, as insects may be energetically challenged by higher salinities, while lower salinities may be more challenging for other freshwater taxa.

A5.27 DEALING WITH DROUGHT: CONNECTING DOTS FROM BEHAVIOUR TO PATHWAYS

Friday 7 July 2023 10:15

A5.28 OSMOREGULATORY MECHANISMS OF A SALINE-TOLERANT MOSQUITO IN CHANGING ENVIRONMENTS

Friday 7 July 2023

11:00

Andrea C Durant (University of Miami, United States), Erik J Folkerts (University of Miami, United States), Martin Grosell (University of Miami, United States)

acd92971@miami.edu

The aquatic larvae of some (~ 5%) species of mosquito are euryhaline osmoregulators. While capable of surviving and thriving in freshwater habitats, eggs are preferentially laid, and the larvae hatch, in saline water to avert competition and predation. In comparison to freshwaterrestricted larvae, salt-tolerant larvae exhibit morphological changes to osmoregulatory organs (i.e. the rectum) and secrete a hyper-osmotic urine in seawater. Here, we detail the functional significance of the distinct rectal segments and the renal Malpighian tubules of black salt marsh mosquito (Aedes taeniorhynchus) larvae reared in either dilute freshwater or seawater. Tidal marshlands experience natural fluctuations in water chemistry parameters (e.g. temperature and salinity), but departures from historical averages are increasingly being documented and are predicted to have grave impacts on marshland biodiversity. In our preliminary analysis of the effects of multi-generational (6 generations) exposure of larvae to seawater with elevated temperature, we observe maladaptive impacts to metabolic rates, development, anti-predator behaviours, and overall osmoregulatory capabilities in a warmer and saltier environment.

David Buchwalter (North Carolina State University, United States), Jamie Cochran (North Carolina State University, United States)

A5.29 DROSOPHILA MELANOGASTER LOCO MUTANTS HAVE DECREASED WATER LOSS AND IMPROVED SURVIVAL WHEN STRESSED WITH HIGH DIETARY SALT.

Friday 7 July 2023

11:30

Gayani Nanayakkara (Eccles Insitute of Human Genetics The University of Utah, United States), Catherine Henry (Eccles Institute of Human Genetics The University of Utah, United States), Aylin Rodan (Eccles Insitute of Human Genetics The University of Utah, United States)

u6023761@utah.edu

We previously showed that heterozygous loss-of-function mutations in locomotion defect (Δloco/+) protects against high salt (0.3M NaCl) lethality in Drosophila melanogaster. Here, we investigated the physiological adaptations of Δloco/+ mutants to high salt. Total body water measurements demonstrated that unlike genetically matched controls, high salt-fed Δloco/+adult flies do not become dehydrated after 24 hours of high salt feeding. This could be due to differences in: 1) consumption; 2) cuticular water loss (transpiration); 3) respiratory water loss; and/or 4) excretory water loss. CAFÉ assays demonstrated no differences in high salt food consumption between controls and mutants. Cuticle water permeability in dead flies was slightly increased in Δloco/+ compared to controls, arguing against decreased transpiration in Δloco/+ mutants. Since respiratory water loss depends in part on activity, we used Drosophila Activity Monitors to measure locomotor activity over three days. Δloco/+ had decreased activity compared to controls when fed normal diet, but there was no difference between genotypes on high salt. Using homemade respirometers, we demonstrated that high salt-fed Δloco/+ and controls have similar oxygen consumption when measured over 3 hours. In response to high salt, controls have increased osmole excretion, which is blunted in Δloco/+ mutants. This could lead to less excretory water loss in the mutants due to less osmotic water loss to the gut from the hemolymph. Therefore, we conclude that Δloco/+ mutants may employ protective mechanisms to minimize osmolyte excretion, enabling water retention and improved survival when subjected to high salt stress.

A5.30 THE REGULATION OF AQUAPORIN EXPRESSION FOLLOWING A BLOOD MEAL IN MOSQUITOES

Friday 7 July 2023 11:45

Britney N Picinic (York University, Canada), Jean-Paul Paluzzi (York University, Canada), Andrew Donini (York University, Canada)

britneyp@my.yorku.ca

The mosquito,Aedes aegypti, is a vector for several arboviral diseases including Zika virus, Dengue and yellow fever. A. aegypti inhabit tropical and sub-tropical regions around the globe, where females acquire blood meals from vertebrate hosts to produce mature eggs. Acquiring a blood meal poses an osmoregulatory challenge for mosquitoes, where an increase of fluid and ions is rapidly excreted as urine produced by the Malpighian tubules (MTs) and processed by the hindgut. Transmembrane domain proteins known as aquaporins (AQPs), allow for the movement of water across the cell membrane

and it has been shown that a blood meal in female A. aegypti results in changes to their transcript levels. There are six identified AQPs in A. aegypti, where AQP1,2, and 6 are water specific AQPs and AQP4 and 5 are known as entomoglyceroporins, which can transport some solutes, in addition to water. In this study, AQP1 and 4 have been localized to the MTs in female A. aegypti and through western blot analysis, we have shown that AQP4 protein levels are significantly reduced 24hr after a blood meal. In addition, immunogold staining indicated a sub-cellular change in AQP1 localization that was evident 30 minutes after a blood meal. Studies using RNAi to knockdown AQP1 expression will study the physiological importance of AQP1 in urine production and excretion by the MTs.

A5.31 THE SECONDARY CONSEQUENCES OF IONOREGULATORY COLLAPSE: LATENT CHILLING INJURY AND IMMUNE ACTIVATION IN CHILL SUSCEPTIBLE INSECTS

Friday 7 July 2023

12:00

Heath A MacMillan (Carleton University, Canada)

heathmacmillan@cunet.carleton.ca

Maintaining internal salt and water balance in response to Chilling injuries in model chill-susceptible insects are a consequence of stressful low temperature exposures. They manifest as a loss of neuromuscular function (e.g. an inability to stand, walk, or fly) that is driven by muscle cell death. A failure of renal ionoregulation leads to a systemic collapse of ion gradients in the cold. The resulting cell membrane depolarization can explain injuries that are sustained during a cold stress and evident shortly upon rewarming. Not all damage is immediately apparent, however, and effects of cold stress can manifest with some delay. After a chilling stress is alleviated, chilling also causes upregulation of genes in the insect immune pathways, some of which are also upregulated following other forms of sterile stress. In this talk, I will provide evidence for sex-specific “latent” chilling injuries inDrosophila melanogasterthat may arise from cell damage/death and immune activation triggered by a cold stress. By integrating this new data with recent work on the roles of reactive oxygen species (ROS), damage associated molecular patterns (DAMPs) and anti-microbial protein (AMP) expression in insects, I will propose a conceptual model for latent chilling injury that links ionoregulatory collapse with secondary consequences that can drive further tissue damage and immune activation following cold stress.

A6 BRIGHT NIGHTS WITH DARK CONSEQUENCES: THE EVOLUTIONARY ECOLOGY OF COPING WITH LIGHT POLLUTION

ORGANISED BY: FRANZ HÖLKER LEIBNIZ (INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES), NEDIM TÜZÜN (LEIBNIZ INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES), SIBYLLE SCHROER (LEIBNIZ INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES)

A6.1 BEHAVIOURAL RESPONSES TO ARTIFICIAL-LIGHT-AT-NIGHT AND THE ECOLOGICAL AND EVOLUTIONARY CONSEQUENCES

Wednesday 5 July 2023 09:00

Ulrika Candolin (University of Helsinki, Finland)

ulrika.candolin@helsinki.fi

Artificial light at night (ALAN) is a growing global problem that influences the composition and functioning of ecosystems by altering the behaviour of organisms. In this talk I will explain the factors that determine how an individual responds, and what the consequences of the responses are, from the individual to the ecosystem level. I will further discuss the potential of species to genetically adapt to light pollution and the research done to investigate this. To illustrate the topic, I will use examples from our work on glow-worms, gammarids, and stickleback. I will present results from a literature search that reveals that although an increasing number of studies find light pollution to alter the behaviour of organisms, the fitness consequences of these behavioural responses are still largely unknown, as are their impacts on populations, communities, and ecosystems. I will end with indicating topics particularly in need of more research.

ellen.cieraad@nmit.ac.nz

Artificial light at night (ALAN) strongly affects moth physiology and behaviour, however the extent to which ALAN is a selective pressure that drives adaptation and evolution in moths remains unknown. We assessed whether feeding and calling behaviours of Yponomeuta cagnagellus moths are locally adapted to ALAN. Collected from locations that were either illuminated or dark at night-time for several decades, moths were exposed to different light intensities in a laboratory experiment.

Male moths, but not female moths, fed less frequently in bright light than in dark or dim conditions. Female calling was less frequent in dimly or brightly lit conditions than in the dark treatment. Individuals from illuminated source populations showed increased feeding behaviour by males and marginally decreased calling behaviour by females.

Our study suggests that ALAN affects the phenotypical calling behaviour by females and feeding behaviour by male moths of Y. cagnagellus but has not resulted in adaptation. Long-term ALAN conditions also affected feeding and marginally affected calling frequency. Reduced calling in lit conditions, perhaps driven by a reduced need for such behaviour because of an increase in visual cues or through the proximity of individuals in lit conditions, may result in long-term adaptation.

A6.3 ARTIFICIAL LIGHT AT NIGHT AFFECTS CRICKET STRIDULATION UNDER SEMI NATURAL CONDITIONS

Wednesday 5 July 2023 09:45

Wednesday 5 July 2023 09:30

Keren Levy (Tel Aviv University, Israel), Amir Ayali (Tel Aviv University, Israel), Anat Barnea (The Open University of Israel, Israel) kerenlevy@mail.tau.ac.il

Perceiving and adjusting to environmental cues is crucial for all organisms. In most animals, including insects, the rhythmic cycle of day and night serves for timekeeping, i.e., synchronizing daily activity patterns, and regulating internal processes. Artificial light

A6.2 LONG-TERM EXPOSURE TO ARTIFICIAL LIGHT AT NIGHT DOES NOT INDUCE LOCAL ADAPTION OF FEEDING AND CALLING BEHAVIOURS BY THE MOTH YPONOMEUTA CAGNAGELLUS

Ellen Cieraad (Te Pukenga - New Zealand Institute of Skills and Technology, New Zealand), Roy Van Grunsven (Dutch Butterfly Association, Netherlands), Emily Strange (Leiden University, Netherlands)

at night (ALAN), a widespread anthropogenic pollutant, disrupts the natural day–night cycle, and negatively impacts animals at various levels. However, our knowledge on the intricate effects of ALAN on nocturnal insects is still limited. We inspected the effects of different ALAN intensities on stridulation behaviour of adult male Gryllus bimaculatus crickets exposed to shaded natural lighting and temperature conditions. Individual males were housed in outdoor aquaria, in a semi-natural environment, and subjected to one of several treatments: daylight:darkness (LD), daylight:ALAN of 2, 5, 15, 100, 400 lux, or constant 1500 lux. The crickets’ stridulation behaviour was continuously recorded for 14 consecutive days and nights. We compared the medians and variances of the period of daily activity rhythms among the groups. Crickets exposed to the natural LD cycles exhibited a rhythm of 24h, displaying nocturnal stridulation. ALAN conditions affected the timing of activity and evoked light-intensity-dependent free-running behaviour, resulting in a decrease in the proportion of synchronized crickets. Furthermore, the medians of the activity periods differed significantly between the LD and ALAN treatments >100 lux (Kruskal-Wallis test, p<0.05). Our results demonstrate an ALANinduced loss of timekeeping of the individuals, resulting in an ALANintensity-dependent desynchronization of the population, even under semi-natural conditions, and confirm the ecological threats of ALAN.

A6.4 SEXUAL DIFFERENTIATION

RESPONSES

NOCTURNAL

Wednesday 5 July 2023 10:00

Bridgette Farnworth (Nelson Marlborough Institute of Technology, New Zealand), John Innes (Manaaki Whenua – Landcare Research, New Zealand), Catherine Kelly (Department of Agriculture and Fisheries (Queensland), Australia), Joseph R. Waas (Algoma University, Canada)

bridgette.farnworth@outlook.com

Globally, artificial light at night (ALAN) has increased dramatically in the last two decades and is proposed as a major driver of invertebrate decline. However, the adverse effects of ALAN on many of Aotearoa New Zealand’s native species remains unknown; in particular, little is known about terrestrial invertebrate responses to altered lighting regimes. We investigated how flightless orthopterans responded to artificial light at Maungatautari Ecological Island (Waikato, New Zealand). Based on their nocturnal behaviour, ecology and evolutionary history, we predicted that the endemic tree wētā (Hemideina thoracica) and cave wētā (Rhaphidophoridae) would reduce their activity under illumination. Experimental stations were exposed to three evenings under light or dark treatments and wētā visitation rates were analysed from images captured on infra-red trail cameras set up at each station. Light significantly reduced the number of observations of cave (71.7% reduction) and tree wētā (87.5% reduction). In observations where sex was distinguishable (53% of all visits), male tree wētā were observed significantly more often (85% of visits) than females (15% of visits) and while males avoided illuminated sites, no detectable difference was observed across treatments for females. Sex could not be distinguished for cave wētā. Our findings have implications for the conservation of invertebrate diversity and abundance within natural and urban ecosystems that may be affected by light pollution. The increasingly prevalent use of light at night highlights the importance of lighting regulations for Aotearoa New Zealand’s unique ecology and cultural heritage.

A6.5 PLANT-POLLINATOR INTERACTIONS IN AN INCREASINGLY ILLUMINATED WORLD

Wednesday 5 July 2023 11:00

Eva Knop (Agroscope University of Zurich, Switzerland)

eva.knop@ieu.uzh.ch

The artificially illuminated area at night has rapidly increased over the past decades, so that to date a growing proportion of the world’s ecosystem are exposed to light at night. It is increasingly recognized that artificial light at night can have detrimental effects on species occurrence, reproduction, and survival by influencing physiological and behavioral processes. I will focus on what we currently know of how plant-pollinator interactions are affected by artificial light at night, and on how this might change the pollination service they provide. Also, I will elucidate potential direct and indirect mechanisms, that drive the found patterns. For example, a change of interactions due to artificial light at night might not be limited to the illuminated area as some pollinators actively fly away from the disturbed area leading to intensified interaction frequencies in adjacent and dark areas. In sum, I will show that artificial light at night can have a major direct and indirect impact on plant-pollinator communities which goes beyond short-term and local effects and consequences for the functioning of the communities.

A6.6 ARTIFICIAL LIGHT AT NIGHT INCREASES TOP-DOWN PRESSURE ON CATERPILLARS: EXPERIMENTAL EVIDENCE FROM A LIGHT-NAIVE FOREST

Wednesday 5 July 2023 11:30

John F Deitsch (Department of Entomology Cornell University, United States), Sara A Kaiser (Center for Biodiversity Sciences Cornell Laboratory of Ornithology Cornell University, United States)

jfd77@cornell.edu

Artificial light at night (ALAN) is a globally widespread and expanding form of anthropogenic change that impacts arthropod biodiversity. ALAN alters interspecific interactions between arthropods, including predation and parasitism. Despite their ecological importance as prey and hosts, the impact of ALAN on larval arthropod stages, such as caterpillars, is poorly understood. We examined the hypothesis that ALAN increases top-down pressure on caterpillars from arthropod predators and parasitoids. We experimentally illuminated study plots with moderate levels (10–15 lux) of LED lighting at light-naive Hubbard Brook Experimental Forest, New Hampshire. We measured and compared between experimental and control plots: (i) predation on clay caterpillars, and (ii) abundance of arthropod predators and parasitoids. We found that predation rates on clay caterpillars and abundance of arthropod predators and parasitoids were significantly higher on ALAN treatment plots relative to control plots. These results suggest that moderate levels of ALAN increase top-down pressure on caterpillars. We did not test mechanisms, but sampling data indicates that increased abundance of predators near lights may play a role. This study highlights the importance of examining the effects of ALAN on

both adult and larval life stages and suggests potential consequences of ALAN on arthropod populations and communities.

A6.7 PUSHING BOUNDARIES –INTERACTION OF ARTIFICIAL LIGHT AND VEGETATION DRIVES SPATIAL BEHAVIOUR OF A SYNANTHROPIC BAT

Wednesday 5 July 2023 11:45

Claire T.P. Hermans (Netherlands Institute of Ecology (NIOOKNAW), Netherlands), Harm M. Bartholomeus (Laboratory of Geo-Information Science and Remote Sensing Wageningen University and Research, Netherlands), Jens C. Koblitz (Max Planck Institute of Animal Behavior, Germany), Marcel E. Visser (Netherlands Institute of Ecology (NIOO-KNAW), Netherlands), Kamiel Spoelstra (Netherlands Institute of Ecology (NIOO-KNAW), Netherlands)

c.hermans@nioo.knaw.nl

Artificial light at night has a negative impact on our natural environment, especially on nocturnal species like bats. Bats avoid light at night because of the risk of predation: the safety of darkness is the essence of their temporal niche. While slow-flying bat species need to be extra prudent, fast-flying and agile bat species utilize accumulated insects around light sources for foraging. At such locations, bats face a tradeoff between the risk of predation and increased foraging efficiency

In order to study the impact of light intensity on foraging bats, bats were acoustically tracked with microphone arrays while flying around light posts experimentally placed in a natural habitat at seven sites in the Netherlands. The presence of vegetation close to streetlights may reduce predation risk and hence enable bats to forage closer to light sources. Vegetation therefore potentially interacts with the distance relationship between bat activity and light intensity. In order to quantify this interaction, we precisely linked a LiDAR based 3D vegetation map with high-resolution bat flight tracks around experimental light posts. Our work provides novel information on the impact of artificial light on bat activity, more specifically on the relation between light intensity and bat foraging activity. We further show how bat activity around light sources is spatially affected by vegetation structure, altering natural niche segregation between bat guilds. The presence of light may therefore induce a selective advantage for synanthropic bats in the Anthropocene, especially when vegetation facilitates foraging close to lights.

Carolyn Burt (Colorado State University, United States), Jeffrey Kelly (University of Oklahoma, United States), Grace Trankina (University of Oklahoma, United States), Carol Silva (University of Oklahoma, United States), Ali Khalighifar (Colorado State University, United States), Hank JenkinsSmith (University of Oklahoma, United States), Andrew Fox (University of Oklahoma, United States), Kurt Fristrup (Colorado State University, United States), Maggie LeonCorwin (University of Oklahoma, United States), Cheyenne Black (University of Oklahoma, United States), Kyle Horton (Colorado State University, United States)

carolyn.burt@colostate.edu

Light pollution is a global threat to biodiversity, especially migratory organisms, some of which traverse hemispheric scales. Research on light pollution has grown significantly over the past decades, but our review on migratory organisms demonstrates gaps in our understanding, particularly beyond migratory birds. Research across spatial scales reveals the multifaceted effects of artificial light on migratory species, ranging from local scales through collisions with lit structures, at regional scales by altering stop-over sites and aerial connectivity of the night sky, and at macroscales through exposure to sky glow and altered phenology. These threats extend beyond species active at night — broadening the scope of this threat. Emerging tools for measuring light pollution and its impacts, as well as ecological forecasting techniques, present new pathways for conservation, including transdisciplinary approaches.

A6.9 WHAT HAPPENED TO THE DARK AT NIGHT: A BIRDS' PERSPECTIVE

Wednesday 5 July 2023 12:15

URuben Evens (Antwerp University, Belgium), Bart Kempenaers (Max Planck Institute for Biological Intelligence, Germany), Michiel Lathouwers (Hasselt University, Belgium), Marcel Eens (Antwerp University, Belgium)

ruben.evens@uantwerpen.be

Wednesday 5 July 2023 12:00

Animal behaviour has evolved under relatively constant cycles of light and darkness. Nowadays, artificial night lighting disrupts predictable, recurring light cycles, such as the lunar cycle. We investigated the potential consequences of a subtle, broad-scale form of light pollution, skyglow, on individual flight and foraging behaviour of European Nightjars (Caprimulgus europaeus) in Belgium, Mongolia and Africa. By combining space use and activity data of individual nightjars with local measures of moon light, we observe that, in natural habitats tens of kilometres away from urbanised environments, skyglow potentially mimics a moon-lit night in terms of sky brightness. This occurs especially during overcast nights, when the sky should be naturally dark. Nightjars, who are visually-oriented insectivores, respond to such an artificially illuminated sky by increasing nocturnal flight and flycatching activity. This flexibility in light-mediated activity raises the question whether or how individuals and populations adapt to significant changes in their night-time environment.

A6.8 THE EFFECTS OF LIGHT POLLUTION ON MIGRATORY ANIMAL BEHAVIOR

A6.10 IMPACTS OF ARTIFICIAL LIGHT AT NIGHT ON THE EARLY LIFE HISTORY OF TWO ECOSYSTEM ENGINEERS

Wednesday 5 July 2023 15:00

Svenja Tidau (University of Plymouth, United Kingdom), Fraser T. Brough (University of Plymouth, United Kingdom), Luis Gimenez (Bangor University, United Kingdom), Stuart J. Jenkins (Bangor University, United Kingdom), Thomas W. Davies (University of Plymouth, United Kingdom)

svenja.tidau@plymouth.ac.uk

Sessile marine invertebrates play a vital role as ecosystem engineers and in benthic-pelagic coupling. Most benthic fauna develops through larval stages and the importance of natural light cycles for larval biology and ecology is long-established. Natural light-dark cycles regulate two of the largest ocean-scale processes, diel vertical migration and broadcast spawning, which are fundamental for larvae. Given the reliance on light and their ecological role, surprisingly little is known about the impacts of artificial light at night (ALAN) on the early life history of habitat-forming species. We quantified ALAN impacts on larval performance (survival, growth, development) of two cosmopolitan ecosystem engineers in temperate marine ecosystems, the mussel Mytilus edulis and the barnacle Austrominius modestus. Higher ALAN irradiance increased mortality in both species, but the effect on development and growth differed between species, timepoints and with parent. Mytilus larvae under ALAN grew larger during early life stages. In Austrominius ALAN altered the developmental time but the direction differed between offspring from separate parents. Our results show that ALAN is detrimental for larval survival. ALAN impacts of the early life stages of ecosystem engineers have clear implications beyond their population viability but for the ecological communities they support.

A6.11 MULTIDISCIPLINARY APPROACH TO ASSESS THE IMPACTS OF ARTIFICIAL LIGHT AT NIGHT ON WILD ANEMONEFISH

Wednesday 5 July 2023 15:00

Jules Schligler (UAR 3278 CRIOBE BP 1013 PSL Université Paris: EPHE-UPVD-CNRS 98729 Papetoai Moorea French Polyn, French Polynesia), Thibaut Roost (UAR 3278 CRIOBE BP 1013 PSL Université Paris: EPHE-UPVD-CNRS 98729 Papetoai Moorea French Polyn, French Polynesia), Ricardo Beldade (Estación Costera de Investigaciones Marinas and Center for Advanced Studies in Ecology and Biodivers, Chile), Suzanne C Mills (UAR 3278 CRIOBE BP 1013 PSL Université Paris: EPHEUPVD-CNRS 98729 Papetoai Moorea French Polyn, French Polynesia)

julesschligler@gmail.com

Nighttime light pollution is known to impact biological and ecological processes for a wide range of taxa. However, even though a quarter of the world’s coastlines is affected by this stressor, marine organisms have received little attention compared to terrestrial ecosystems.To bridge the gap in our understanding of the impact of Artificial Light At Night (ALAN) on marine ecosystems, we investigated the impact of ALAN on

key life-stages of coral reef fish. All manipulations were carried out on wild orange-fin anemonefish, Amphiprion chrysopterus, experimentally exposed to ALAN in the lagoon of Moorea, French Polynesia. This multidisciplinary project using physiological (endocrinal responses, respirometry, swimming performance), behavioural (adult parental care, larval escape response) and life-history (reproduction, survival) measures uncovers the impact of ALAN on a coral reef fish. We found contrasted impacts as a function of the life stage considered. Various effects were found both on adult anemonefish and on their offspring. For instance, by extending their foraging time, growth rate increased and nocturnal activity was significantly affected by light pollution. Regarding their offspring, numerous effects were also found, for example on embryonic heart rate and larval swimming performance. Overall, our results highlight the complexity of the effects of ALAN throughout the life of fish and lack of knowledge regarding this topic. Our work is now dedicated to determining whether offspring effects are indirect through transgenerational plasticity or direct during egg development, as well as whether they can acclimate, offering a glimmer of hope for species exposed to nighttime light pollution.

A6.12 LIGHTS, CAMERA, ACTION: UNRAVELLING ZOOPLANKTON DVM UNDER LIGHT AT NIGHT BY EXPLOITING AI IMAGING TOOLS

Wednesday 5 July 2023

15:30

Ashton L Dickerson (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany), Andreas Jechow (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany), Michelle Nößler (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany), Jens Nejstgaard (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany), Franz Hölker (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany)

ashton.dickerson@igb-berlin.de

Diel vertical migration (DVM) of zooplankton is the largest synchronized mass migration on Earth. At night, zooplankton migrate towards highly productive surface waters to feed and return to deeper waters at daybreak to avoid visual predators. Light is the main proximate cue that triggers DVM and the magnitude and depth of DVM is affected by the lunar cycle; dark nights provide more protection for zooplankton from visual predators like fish, while brighter nights (e.g., during full moon) can lead to increased predation in surface waters resulting in smaller DVM amplitudes. It is less clear whether artificial light at night (ALAN) affects zooplankton DVM, which can brighten an area up to 100 times what is natural. While numerous studies describe the change in DVM movement across lunar cycles, historical methods have limited spatial or temporal resolution, meaning current baseline measurements of natural light at night on DVM behaviour are coarse, further complicating our ability to predict how ALAN affects urban freshwater zooplankton behaviour. Here, we used state-of-the-art in situ imaging and high-throughput image analysis to determine zooplankton vertical distribution in open waters at unprecedented spatio-temporal resolution. We measured in a near-pristine environments to gain baseline information of DVM under natural light conditions across the lunar cycle and compare these findings to measurements taken at different ALAN scenarios.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A6.13 ARTIFICIAL LIGHT AT NIGHT IN FRESHWATERS: EFFECTS ON AQUATIC INSECTS UNDER A MULTI-STRESSOR SCENARIO

Wednesday 5 July 2023 POSTER SESSION

João L. T. Pestana (CESAM Department of Biology University of Aveiro Portugal, Portugal), Joana Carmo (CESAM Department of Biology University of Aveiro Portugal, Portugal), Bruna Silva (CESAM Department of Biology

University of Aveiro Portugal, Portugal), Diana Campos (CESAM Department of Biology University of Aveiro Portugal, Portugal), Luisa Machado (CESAM Department of Biology

University of Aveiro Portugal, Portugal), Isabel Lopes (CESAM Department of Biology University of Aveiro Portugal, Portugal)

jpestana@ua.pt

Light pollution is an emergent environmental issue and many health and ecological detrimental effects of artificial light at night (ALAN) have been recently described. However, research on responses of aquatic invertebrates and on the ecological consequences of ALAN to freshwaters is still much needed. Besides light pollution, other stressors like pesticide contamination or elevated temperatures are commonly present in urban aquatic ecosystems. We hypothesize that exposure to ALAN can magnify the effects of warming and of chemical contamination by altering the tolerance of exposed organisms.

We present preliminary data showing that exposure to low and environmentally relevant levels of ALAN (0-10 lux) not only reduce feeding and growth of Chironomus riparius larvae but also increase their sensitivity to pesticide exposure and to thermal stress. We determined the Critical thermal maximum (CTmax) in C. riparius larvae after exposure to three ALAN conditions (0,1, and 10 lux during night-time). The results show that ALAN decreases the upper thermal tolerance of C. riparius larvae (CTMax). Pesticide sensitivity was evaluated through survival curves (time-to event analyses) where C. riparius larvae reared in the same ALAN treatments (0 and 10 lux during night-time) were exposed to a lethal Glyphosate (Roundup) concentration. Significantly different survival curves indicate a higher sensitivity of larvae which were previously exposed to ALAN. Ongoing work is investigating the physiological bases for the decreased tolerance (e.g heat shock proteins/ oxidative stress) and validating results with different stressors (e.g. neonicotinoids, salinity) and using also chronic, sub-lethal assays.

A6.14 DOES EXPOSURE TO ARTIFICIAL LIGHT AT NIGHT ALTER THE SUBSEQUENT DAYTIME BEHAVIOUR OF AN ENDANGERED FRESHWATER FISH?

Wednesday 5 July 2023 POSTER SESSION

Christine Madliger (Algoma University, Canada), Zintis Stasko (Carleton University, Canada), Steven Cooke (Carleton University, Canada), Trevor Pitcher (University of Windsor, Canada)

christine.madliger@algomau.ca

The extent of the Earth that is exposed to light pollution is increasing annually. For almost all organisms, predictable light-dark cycles are essential to initiating and controlling processes such as foraging, sleep and rest, growth, and reproduction. By altering physiology and behaviour, changes in the brightness, spectra, or timing of artificial light can therefore have detrimental downstream consequences for organismal performance and fitness. While overall research efforts aimed at understanding the effects of light pollution have been increasing, aquatic organisms remain understudied in comparison to their terrestrial counterparts. Using an endangered fish species that is facing threats from urbanization, the Redside Dace (Clinostomus elongatus), we investigated whether overnight exposure to artificial light resulted in differences in subsequent diurnal behaviour in comparison to a dark-exposed control. We measured behaviours related to overall activity and risk-taking and exposed treatment groups to lights of two different spectra with brightness levels comparable to streetlighting. We further compared two life stages, juvenile and adult, to determine whether age influences the response of individuals to artificial light exposure. Our results will provide information on whether changing the spectrum of light can alter the consequences of light pollution for ecologically-relevant behaviours. In addition, these results will contribute to our overall understanding of light pollution as a potential threat to small-bodied fishes and will inform the threat assessment process for an endangered species in Canada.

A7 RAPID EVOLUTION OF INVASIVE POPULATIONS DUE TO ANTHROPOGENIC CHANGES

JEHAN-HERVÉ LIGNOT (UNIVERSITY OF MONTPELLIER), DIANA MARTINEZ-ALARCON (UNIVERSITY OF MONTPELLIER), ANTOINE FRAIMOUT, (UNIVERSITY OF MONTPELLIER)

A7.1 EXPERIMENTAL BIOLOGY OF SPECIES GEOGRAPHIC RANGES

Thursday 6 July 2023 09:00

Eric Edeline (INRAE, France), Agnès Stark (INRAE, France), Yoann Bennevault (INRAE, France), Jean-Marc Paillisson (CNRS, France), Eric J Petit (INRAE, France)

eric.edeline@inrae.fr

Experimental approaches in biology are often constrained logistically to study low levels of biological organization across small spatial and temporal scales. These constraints largely restrict experimental biologists working on species geographic ranges to study physiological response to climate-related factors, and to assume that geographic distributions reflect physiological tolerance. However, in the reality population-level processes, like ecological interactions and dispersal limitation, may severely narrow realized species distributions compared to physiological-tolerance envelopes. We will present why and how experimental mesocosms and mark-recapture techniques, by allowing population-level inference, may contribute to scale up the predictive power of experiments on the biology of species geographic ranges. We will provide an illustration with an experiment on the effects of temperature and population density on survival and dispersal in the Louisiana crayfish (Procambarus clarkii), a species of invasive concern in many freshwater ecosystems worldwide. We will also briefly discuss how mesocosms may integrate processes acting at higher levels of biological organization, such as the community level.

urbanisation on streams are so intense and consistent that a supposedly general ‘urban stream syndrome’ has been proposed. However, most of these effects were investigated in developed countries where the leading ‘symptom’ are changes in hydrology. In developing countries, on the other hand, contamination by untreated sewage is likely to override hydrological changes as a leading reorganizing factor for biodiversity for its potential to severely constrain the capacity of fishes to thrive in such environments. Therefore, as a first step in a broader research program to unravel the consequences of urbanisation to freshwater biodiversity, we sampled Poeciliid fishes known to occur in urban areas alongside with different water chemistry and structural parameters in 30 third-order streams draining watersheds distributed across a full gradient in urban infrastructure cover in the metropolitan region of São Paulo (Brazil). We found that the two native species Phalloceros reisi and Phalloceros harpagos were only abundant at the beginning of the urban coverage gradient while the introduced Poecilia vivipara and Poecilia reticulata were abundant at intermediate and high percentages of urban coverage. The streams in highly urbanised watersheds also exhibited remarkably lower dissolved oxygen, higher pH and higher conductivity levels, as well as a higher number of pharmaceuticals. This study should guide future experimental approaches that will define both physiological and ecological constraints related to the occurrence of fish in urban hydroscapes of developing countries.

A7.3 EVOLUTION OF WING SHAPE DURING THE WORLDWIDE INVASION OF DROSOPHILA SUZUKII

Thursday 6 July 2023 09:45

Thursday 6 July 2023 09:30

Rodolfo M Pelinson (São Paulo State University (Unesp), Brazil), Denise C Rossa-Feres (São Paulo State University (Unesp), Brazil), Luis Schiesari (University of São Paulo (USP), Brazil)

rodolfopelinson@gmail.com

Human populations historically occupy areas close to streams and rivers, posing important threats to these ecosystems. The effects of

Antoine Fraimout (UMR MARBEC - Université de Montpellier, France), Stéphane Chantepie (Muséum National d'Histoire Naturelle, France), Nicolas Navarro (UMR Biogéosciences - Université de Dijon, France), Céline Téplitsky (UMR CNRS CEFE, France), Vincent Debat (UMR ISyEB - Muséum National d'Histoire Naturelle, France)

antoine.fraimout@umontpellier.fr

the genetic correlations summarized in the genetic covariancematrixGand howGitself evolves throughout period of drift and selection. Here, we study the evolution of theGmatrix using natural populations of the highly invasive pestDrosophila suzukii,whose invasion history was resolved by population genetics approaches. We comparedGmatrices estimated from wing shape data among ancestral native and derived

A7.2 EXPERIMENTAL BIOLOGY OF SPECIES GEOGRAPHIC RANGES

ORGANISED BY:

invasive populations of known history in Asia, Europe and USA, and contrasted the patterns of quantitative divergence among populations to neutral expectations. Our results suggest moderate yet significant quantitative genetic differentiation amongD. suzukiipopulations and relative stability in the structure ofG. Interestingly, comparison of between-population divergence with ancestral genetic (co)variances suggests that divergence among populations is greater than expected under a purely neutral model of evolution, and could be indicative of an effect of selection on wing shape.

A7.4 THE IMPORTANCE OF BROAD THERMAL TOLERANCE IN THE SEA LAMPREY’S SUCCESSFUL INVASION OF THE LAURENTIAN GREAT LAKES OF NORTH AMERICA

Thursday 6 July 2023 10:00

Michael Wilkie (Wilfrid Laurier University, Canada), Milica Koledin (Wilfrid Laurier University, Canada), Joshua Sutherby (University of Manitoba, Canada), Hugo Flávio (Wilfrid Laurier University, Canada), Ken M Jeffries (University of Manitoba, Canada)

mwilkie@wlu.ca

Sea lamprey (Petromyzon marinus) invaded the Laurentian Great Lakes in the late 1800-early1900s through man-made canals, and devastated fisheries by preying upon salmonid fishes. Native to the Atlantic Ocean, anadromous sea lamprey spend 3-7 years in freshwater streams as filter-feeding larvae before metamorphosing into parasitic juvenile lamprey which migrate to sea and feed on a variety of fishes. Depending upon movements of their hosts, sea lamprey may end up 100-1000s of km from their natal streams when they spawn. For this reason, larval lamprey would likely require physiological flexibility to cope with differences in the water quality and temperature of novel habitats. We sought to test the hypothesis that broad thermal tolerance was key to the sea lamprey’s establishment in the Great Lakes. Thermal performance studies using intermittent-flow respirometry revealed that larval sea lamprey had low standard metabolic rates (SMR; ~1.0 μmol O2 g-1 h-1 ) and were relatively robust to changes in temperature as demonstrated by Q10 values of ~1.75 between 10-20°C and ~2.0 between 21-25°C. Aerobic metabolic scope (AMS) ranged from 6.610.9 μmol O2 g-1 h-1 between 6-25°C, with a thermal optima of 26.6°C where AMS averaged 15.8 μmol O2 g-1 h-1. Depending upon acclimation temperature, CTmax values were between 33.3-35.2°C. Relatively high temperatures (~24-26°C) were also required to induce greater mRNA expression of cellular stress response proteins (E.g. JUN, HSP90B1; SERPINH1A). We conclude that a broad thermal tolerance contributed to the successful invasion of the Great Lakes by sea lamprey, and that further range shifts are possible with climate change.

ragriffi@ualberta.ca

The introduction of invasive species can have a devastating impact on an ecosystem, often through predation and competition with native organisms. The European green crab (Carcinus maenas) is an extremely successful invasive species, thriving in marine environments around the world, and known for their tolerance to environmental stress. The success of an invasive species often depends on their ability to thrive in new environments. Here, using a multi-stressor approach, we evaluated the upper thermal tolerance of the green crab in combination with various environmental challenges present within estuarine environments. In particular, we investigated how changes in environmental salinity, dissolved oxygen, and waterborne copper influence the critical thermal maximum (CTmax)and fitness of the green crab. First, six male crabs were assigned to each of the following treatment groups, control, 50% oxygen saturation, 150% oxygen saturation, 50% salinity, 20% salinity, 0% salinity, 200 µg/L, or 600 µg/L copper, and CTmax was assessed. No significant differences in CTmax were found in response to changes in environmental salinity or dissolved oxygen. However, control green crab exhibited a CTmax of approximately 37.6 ± 0.3 °C, while copper exposed green crab exhibited significantly reduced CTmax values in both the 200 µg/L (36.7 ± 0.1 °C) and 600 µg/L (36.6 ± 0.3 °C) treatments. Heart rate, maximum metabolic rate, resting metabolic rate, and copper accumulation in the heart, hemolymph, and gill are also assessed. This research offers valuable information regarding C. maenas’ tolerance to environmental stress, which may play a vital role in their invasive success.

A7.6 GENOMIC MECHANISMS OF PARALLEL ADAPTATION DURING HABITAT INVASIONS

Thursday 6 July 2023 11:00

Carol Eunmi Lee (University of Wisconsin Madison, United States)

carollee@wisc.edu

Thursday 6 July 2023 10:15

Human activity is causing populations to experience drastic environmental change, due to phenomena such as biological invasions and climate change. Many invasive populations are experiencing rapid changes in habitat salinity. However, fundamental mechanisms that enable certain populations to rapidly adapt to novel habitats remain poorly understood. In recent years, populations of the copepod Eurytemora affinis complex have invaded freshwater habitats multiple times independently from saline sources. These copepods are dominant grazers in aquatic habitats throughout the Northern Hemisphere and support major fisheries. Intriguingly, we discovered that evolutionary changes during salinity transitions repeatedly involve the same loci (and SNPs) in wild populations and laboratory selection lines far beyond expectations. In both wild populations and laboratory lines, ion transporter genes dominate as the functional category undergoing natural selection. Using extensive simulations, we found that this degree of parallelism was consistent with positive synergistic epistasis among alleles, where selection on one allele promotes selection on other related alleles. Our results were consistent with mechanisms of ion uptake from dilute habitats, requiring the coordinated action

Robert A Griffin (University of Alberta, Canada), Rasmus Ern (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway), Tamzin A Blewett (University of Alberta, Canada)

A7.5 IMPLICATIONS OF A FLUCTUATING ESTUARINE ENVIRONMENT ON THE UPPER THERMAL TOLERANCE IN THE INVASIVE GREEN CRAB

of cooperating ion transporter proteins. Interestingly, temperature adaptation resulted in selection acting on an entirely different set of loci, indicating tradeoffs between salinity and temperature adaptation that would impede adaptation to either factor. Here, we find strong support for a novel and potentially widespread mechanism, namely positive epistasis (in conjunction with selection on standing variation), in promoting parallel polygenic adaptation.

A7.7 ONTOGENETIC DIFFERENCES IN THE THERMAL DEPENDENCE OF METABOLIC RATE IN INVASIVE MARSH FROGS (PELOPHYLAX RIDIBUNDUS).

Thursday 6 July 2023 11:30

Teresa

pablo.padilla@uliege.be

Invasive species contribute to the decline of native populations of amphibians. These invaders can be exotic amphibians which are able to cope with new environmental conditions during their invasion. The complex life cycle that characterizes amphibians may, however, be a limit to the invasion of adults, in particular when facing changes in biotic conditions, such as temperature. Metamorphosis is a costly energetic event that can affect fitness of the adults. Because temperature is known to have an effect on the metabolic rate of organisms, evaluating the energetic cost relatively to thermal changes in invasive amphibians during development appears critical.

We here quantified the oxygen uptake at rest (a proxy of the standard metabolic rate) of tadpoles, climax stages (i.e., tadpoles at metamorphosis), and adult stages at three temperatures. To do so we used marsh frogs (Pelophylax ridibundus), an overlooked invasive species that is colonizing large parts of Western Europe.

When corrected for their body mass, the metabolic rate of tadpoles before and during metamorphosis does not show a significant increase at the intermediate to the highest test temperature. This suggest that warmer pond temperatures, such as those arising from predicted climate changes, will not increase the energetical cost required to fulfill the physiological needs of early stages of invasive marsh frogs. Tadpoles before and during metamorphosis may not be as vulnerable to thermal changes as originally thought, revealing another feature that may have, and will, promote their invasion.

tpopp@wisc.edu

Freshwater invasions by the Eurytemora affinis species complex offers the opportunity to study rapid evolution in the wild. Previous research in the Lee lab had identified ion transporter genes as major targets of selection during rapid salinity decline, including paralogs of Na+ /K+ -ATPase (NKA). This ion transporter was previously localized in the maxillary glands and Crusalis organs potentially contributing to osmotic and ionic regulation. Our goal was to characterize the evolutionary shifts in NKA expression in the maxillary glands to determine how evolution of maxillary gland function contributes to population range expansions into fresh water. Here, we examined the localization and expression of NKA in the maxillary glands of saline versus freshwater populations from the St. Lawrence drainage (N. America) at three common-garden salinities (0, 5, and 15 PSU), using in situ immuno-histochemical staining and western blot fluorescence quantification. We discovered that NKA expression increased in each population at their non-native native salinities, suggesting tradeoffs in different environments (genotype x environment). Notably, under freshwater conditions, maxillary gland NKA showed the evolution of reduced expression in the freshwater population relative to the saline population. Conversely, NKA expression was higher in the freshwater population at higher salinity (15 PSU). These results indicate that maxillary gland NKA function evolved from saline to freshwater habitats, with freshwater populations showing significantly reduced need for maxillary gland NKA expression in freshwater habitats. Funded by MOPGA and US-NSF.

A7.9 SALINE NICHES IN COASTAL HABITATS: EURYHALINITY AND INVASIVE POTENTIAL

Thursday 6 July 2023 12:00

Freire A Carolina (Universidade Federal do Paraná, Brazil)

osmolab98@gmail.com

We will be reminded of the concepts of fundamental versus realized niches with respect to salinity, especially for fishes and invertebrates of coastal habitats. Then, we will discuss putative changes in the breadth of saline niches over evolutionary time and habitat changes. We will then examine a few examples of recent invasions caused by human activity, evaluating patterns of saline niches of invasive versus native or even endemic species. Finally, we will discuss the concept of euryhalinity: classical organismal euryhalinity versus species/population euryhalinity, allied to invasive potential.

Thursday 6 July 2023 11:45

E POPP (Université de Montpellier, France), William Zozaya (Université de Montpellier, France), Sophie Hermet (Université de Montpellier, France), Guy Charmantier (Université de Montpellier, France), Carol E LEE (University of Wisconsin-Madison, United States), Catherine Lorin-Nebel (Université de Montpellier, France)

Pablo Padilla (University of Liege, Belgium), Anthony Herrel (National Museum of Natural History, France), Mathieu Denoël (University of Liege, Belgium)

A7.8 EVOLUTION OF ION TRANSPORTER NA+/K+-ATPASE EXPRESSION IN THE OSMOREGULATORY MAXILLARY GLANDS OF AN INVASIVE COPEPOD

A8 KEEPING THE PACE: INTEGRATING MITOCHONDRIAL AND CELLULAR BIOENERGETICS TO WHOLE-ANIMAL FITNESS IN A CHANGING ENVIRONMENT

ORGANISED BY: ENRIQUE RODRIGUEZ (UNIVERSITY COLLEGE LONDON), ELISA THORAL (LUND UNIVERSITY), NEAL DAWSON (UNIVERSITY OF GLASGOW), STEFANO BETTINAZZI (UNIVERSITY COLLEGE LONDON)

A8.1 AN INTEGRATIVE ‘FISHEYE’ VIEW ON METABOLIC COSTS UNDER ENVIRONMENTAL CONSTRAINTS.

Tuesday 4 July 2023 09:00

Loïc Teulier (Université Claude Bernard Lyon 1, France)

loic.teulier@univ-lyon1.fr

Understanding how organisms can cope with environmental conditions is a mainstream topic, even more so with the current period of rapid climate changes. Anthropogenic global warming induces an increase of averaged temperature, but also an increase of extreme climatic events, such as heatwaves. These quick and large temperature variations could have dramatic consequences on organisms inhabiting freshwater ecosystems, by increasing the metabolic cost of living. Indeed, ectotherms, such as fish, exhibit a metabolic rate closely related to the water temperature. Warmer temperatures induce higher energy expenditure, and therefore higher costs of maintenance and lower energy available for in vivo performance. Intuitively, whole animal performance is linked to cellular efficiency to provide energy, but this relationship is still unclear. Through various studies conducted in our lab combining in vivo experiments (swimming performance, respirometry) and in vitro protocols (high-resolution oxygraphy, mitochondrial efficiency), we dealt with acute vs. chronic, stable, or variable environmental acclimation, to highlight how cellular bioenergetics can show plastic coping responses to let fish perform under environmental constrains.

A8.2 HYPOXIA ACCLIMATION IMPROVES RED MUSCLE MITOCHONDRIAL EFFICIENCY AND AEROBIC SWIM PERFORMANCE IN THE RED DRUM (SCIAENOPS OCELLATUS).

Tuesday 4 July 2023 09:30

Andrew J Esbaugh (University of Texas at Austin, United States), Kerri L Ackerly (University of Texas at Austin, United States), Angelina M Dichiera (University of British Columbia, Canada), Benjamin Negrete (University of British Columbia, United States)

a.esbaugh@austin.utexas.edu

Climate change is increasing the occurrence and severity of marine hypoxia events worldwide. Hypoxia can dramatically impact marine fishes by constraining O2 uptake and reducing the energy available for vital and non-vital functions. Red drum, an economically important estuarine-dependent teleost native to the Gulf of Mexico, have shown a strong ability to acclimate to hypoxia through respiratory plasticity. Specifically, red drum alter the expressed hemoglobin (Hb) pool to improve Hb-O2 affinity, coinciding with reduced critical O2 thresholds and elevated maximum metabolic rates (MMR) in hypoxia. Interestingly, acclimation has no effect on MMR in normoxia, despite the fact that these fish show significantly elevated critical swim speeds. Here, we tested the hypothesis that the observed improvements in swim performance were due to improved mitochondrial efficiency in cardiac and red muscle. Fish were acclimated to hypoxia for 8 days and sampled for cardiac or red muscle tissues, which were subjected to a substrate-uncouplerinhibitor-titration protocol. Tissue samples were also taken and tested for citrate synthase activity and myoglobin transcriptional abundance. While no changes were noted for raw respiration metrics, the OXPHOS capacity, control efficiency, and control ratio were all significantly improved in acclimated red muscle, consistent with our hypothesis. While cardiac muscle did not show any changes in mitochondrial respiration traits, we did observe elevated citrate synthase activity and myoglobin expression. Overall, our work suggests that red drum use a complex suite of responses – including improved O2 affinity, O2 utilization efficiency and glycolytic capacity – to improve performance in O2 poor habitats.

A8.3 THE IMPACT OF HYPOXIA ON CARDIAC PERFORMANCE AND MUSCLE CELLULAR ENERGY IN THE KING SCALLOP, PECTEN MAXIMUS, AFTER SWIMMING

Tuesday 4 July 2023 09:45

Christian Bock (Alfred-Wegener-Institute Helmholtz Centre for Polar- and Marine Research, Germany), Linda Adzigbli (Institute of Biological Sciences University of Rostock, Germany), Inna Sokolova (Institute of Biological Sciences University of Rostock, Germany)

Christian.Bock@awi.de

The king scallop, Pecten maximus, is sensitive to environmental changes such as ocean warming, hypoxia and acidification due to their active and aerobic lifestyle. Our recent study showed that under longterm acclimation to ocean warming and acidification the swimming performance of P. maximus was limited likely due to hypoxemia and low pH in the hemolymph. To test this hypothesis, we investigated the impact of hypoxia (<2% O2 for about 4 h), that reduces the hemolymph oxygen content, on performance parameters of P. maximus using in vivo Magnetic Resonance Imaging in combination with 31 P-NMR spectroscopy. We focused on cardiac performance and mitochondrial oxidative capacity of the adductor muscle during recovery after moderate swimming under hypoxia. Spectra showed distinct signals of high-energy phosphates (ATP, phospho-L-arginine and Pi ), from which the cellular energy content and acid-base status of the adductor muscle was determined. Cardiac MRI revealed barely changed heart rates, but an increased stroke volume under hypoxia. The observed changes were similar to those reported in other scallop species and indicate a hypoxemia induced limitation in performance.

A8.4 FISH MITOCHONDRIAL PLASTICITY AND ADAPTATION TO FRESHWATER HYPOXIA: HOW DOES IT SUPPORT WHOLE-ANIMAL FITNESS?

Tuesday 4 July 2023 10:00

Amélie Crespel (University of Turku, Finland), Ludovic Toisoul (University of Turku, Finland), Alycia Valvandrin (University of Turku, Finland), Eugénie Dufour (University of Turku, Finland), Tiphaine Menguy (University of Turku, Finland), Luisa Bermejo Albacete (University of Turku, Finland), Katja Anttila (University of Turku, Finland)

amelie.crespel@utu.fi

Populations are currently facing important changes in their environmental conditions. While hypoxia (i.e. low dissolved oxygen level in water) events occur naturally, global change and human activities have exacerbated their strength and temporal fluctuations. As escaping the conditions might not be always possible, it is crucial to better understand how the populations can adjust and/or adapt across generations. When directly exposed, individuals may be able to adjust their phenotypes through plasticity, but continued exposure to hypoxia over generations may require adaptation and evolution. Some inter- or trans-generational plasticity may also take place to facilitate the survival of the next generation. As the mitochondrial metabolism

is essential to sustain the animal aerobic functions, a modification of its capacity is likely to alter how animals are able to cope with the environmental changes. Using two populations of wild three-spined sticklebacks (Gasterosteus aculeatus) exposed to different levels of hypoxia conditions in their natural habitats and experimentally exposed to fluctuating hypoxia (30% air saturation during the night and 100% during the day) across generations, we investigate the plastic and evolutionary response of the mitochondrial functions and its impact on the whole animal physiology and behaviour. We showed adaptation in the mitochondrial metabolism as well as adaptation in the fish growth, swimming, and activity. Fish exposed to hypoxia in their natural habitats possessed higher metabolic capacity. Overall, these results highlight the capacity of fish to adapt to environmental changes across generations, likely relying on mitochondrial adaptation to support individual performance.

A8.5 ONTOGENY OF TEMPERATUREDEPENDENT MITOCHONDRIAL PHENOTYPES IN BIRDS

Tuesday 4 July 2023 13:30

Andreas Nord (Lund University Department of Biology, Sweden), Maria Correia (Lund University Department of Biology, Sweden), Imen Chamkha (Lund University Department of Clinical Sciences, Sweden), Eskil Elmer (Lund University Department of Clinical Sciences, Sweden), Elisa Thoral (Lund University Department of Biology, Sweden) andreas.nord@biol.lu.se

There has been a recent spark of interest in how developmental temperature impacts animal form and function, necessitated by the realisation that our future will hold a warmer and more unpredictable climate and fuelled by increased recognition of the fact that most organisms are amenable for developmental priming of physiological and morphological phenotypic expression. Previous work, mostly performed on birds, shows that higher or lower temperature during pre- or perinatal development can influence several compartments of the energy transduction chain across levels of enquiry, ranging mitochondrial function to organismal thermoregulatory performance. It is poorly understood whether such responses reflect adaptation to predispose the animal for life in a particular thermal environment or if they emerge because of deviations from optimal developmental conditions. Insights into these questions require longitudinal studies of cellular and organismal respiration from birth to adulthood, which is difficult to reconcile in most available model. In this talk, I will explore these matters across the bird phylogeny to answer questions pertaining to costs, benefits, and constraints in the context of lifelong matching between developmental and subsequent thermal environments. I will exemplify using own data from a range of experiments addressing how pre- and perinatal thermal conditions impact the ontogeny and thermal sensitivity of mitochondrial function, and how this is related to the ability to counter heat- or cold stress at organismal levels, spanning fertilisation to adulthood. This adds knowledge about the drivers, evolution, and plasticity of animal thermal adaptation, which can be timely in a rapidly changing world.

A8.6 MAXIMAL RATES OF MITOCHONDRIAL OXIDATIVE PHOSPHORYLATION PREDICT TERRITORIAL PERFORMANCE IN BROWN TROUT

Tuesday 4 July 2023 14:00

Darryl McLennan (University of Glasgow., United Kingdom), Agnieszka Magierecka (University of Glasgow., United Kingdom),

Neal J Dawson (University of Glasgow., United Kingdom),

Caroline Millet (University of Glasgow., United Kingdom),

Tom Sloan (University of Glasgow., United Kingdom),

Neil B Metcalfe (University of Glasgow., United Kingdom)

darryl.mclennan@glasgow.ac.uk

In social hierarchies, establishing dominance over competing conspecifics confers better access to food, shelter, and reproductive opportunity. Dominance status has previously been linked to body size and prior residency (i.e., who was there first); however, experimental studies have shown that even when opponents are size- and residencymatched, clear dominance hierarchies often still become established. One explanation for this may be among-individual variation in metabolic rate, since a higher metabolic rate could allow a greater allocation of energy to dominance-related traits, such as aggressive behaviours. In this study, size-matched brown trout (Salmo trutta) were tested for their ability to fight for territories in a landscaped artificial stream tank, based on two days of behavioural observations on colouration, aggressive behaviour and food acquisition. Each individual faced 3 opponents, so that each fish could be ranked from most competitive (winning all three territorial battles) to least (losing all three). We then measured their mitochondrial function. Mitochondrial efficiency (i.e., the number of ATP produced per molecule O2 consumed) was unrelated to any of our measured dominance-related traits. However, we found that maximal rates of oxidative phosphorylation at the mitochondrial level were positively correlated with an individual’s territorial performance – individuals with higher phosphorylation were better at acquiring food, were more aggressive and were therefore more likely to establish overall dominance. This study exemplifies how there can be clear links between mitochondrial bioenergetics and an individual’s overall performance.

heart mitochondrial functions have been pointed out as a candidate modulator of thermal tolerance. In the present study we measured at different temperature the respiration and the hydrogen peroxide efflux from heart mitochondria of Arctic charr. We also tried to relate the thermal sensitivity of mitochondrial metabolism to the fatty acid profile and mitochondrial metabolites of heart. The H2O2 efflux of mitochondria sharply increase at temperature approaching the critical thermal limit of fish but only in conditions of maximal Oxidative phosphorylation (Nadh feeding of complex I, succinate feeding of complex II, and in the presence of ADP). We found a correlation between ROS production and one fatty acid (DPA) but only at 25°C.

A8.8 THE HYPOXIA-CHALLENGED HEART OF THE GOLDFISH (CARASSIUS AURATUS): FROM FUNCTIONAL RESPONSES TO MITOCHONDRIAL MOLECULAR MECHANISMS

Tuesday 4 July 2023 14:30

Mariacristina Filice (University of Calabria, Italy), Alfonsina Gattuso (University of Calabria, Italy), Daniela Amelio (University of Calabria, Italy), Rosa Mazza (University of Calabria, Italy), Alessia Caferro (University of Calabria, Italy), Gaetana Napolitano (University of Naples Parthenope, Italy), Sandra Imbrogno (University of Calabria, Italy), Maria C Cerra (University of Calabria, Italy)

mariacristina.filice@unical.it

Tuesday 4 July 2023 14:15

Pierre U. Blier (Université du Québec à Rimouski, Canada), Pablo Cortes Garcia (NEOM, Saudi Arabia), Felix Christen (Université du Québec à Rimouski, Canada), Maria Angélica Martinez Silva (Université du Québec à Rimouski, Canada), Desrosiers Véronique (Université du Québec à Rimouski, Canada)

pierre_blier@uqar.ca

Understanding the mechanistic causes of thermal sensitivity and tolerance is a compulsory prerequisite to figure out to which extent ectotherms will be able to adapt to climate changes. Identification of the weak physiological traits setting the limits of thermal tolerance will grant documenting its variability and evolvability. Among various traits

The goldfish (Carassius auratus) shows a remarkable ability to tolerate oxygen fluctuations. This allows it to balance energy supply and demand in vital organs, including the heart. By using the goldfish as a natural model of hypoxia-tolerance, we investigated the response of the heart to short (4 days) and prolonged (20 days) exposure to environmental low O2 in terms of basal hemodynamics and mitochondrial equipment. We observed that, compared to the heart of normoxic animals, the isolated and ex-vivo perfused heart of animals exposed to both 4 and 20 days of hypoxia showed significantly higher basal values of stroke volume, cardiac output, stroke work, and power output. Changes in cardiac function were paralleled by a different expression of proteins controlling mitochondrial biogenesis and dynamics. Short hypoxia increased the expression levels of cytochrome c, a marker of mitochondrial abundance, as well as of proteins involved in mitochondrial fission. Moreover, an activation of the PGC1-NRF1/2-TFAM pathway, which controls mitochondrial transcription and biogenesis was also observed. The expression levels of these regulatory proteins were reduced after 20-days of hypoxia, albeit resulting higher than those detected in the normoxic counterpart.Results suggest that in the goldfish heart, protracted hypoxia induces an increase of mitochondrial content; this in turn, by optimising energy delivery to the contractile apparatus, contributes to preserve, or even enhance, its basal performance.

A8.9 ADVANCES AND POTENTIAL PITFALLS IN MITOCHONDRIAL RESPIROMETRY IN FISH

Tuesday 4 July 2023 14:45

A8.7 MITO, YOU ARE TOO HOT! PLEASE DON’T BREAK MY HEART.

Felix C Mark (Alfred Wegener Institute for Polar and Marine Research, Germany), Megan Barnes (University of Nottingham, United Kingdom), Isabel Ketelsen (Alfred Wegener Institute for Polar and Marine Research, Germany), Lisa Chakrabarti (University of Nottingham, United Kingdom), Maria Eugenia Lattuca (Centro Austral de Investigaciones Científicas (CADIC-CONICET), Argentina)

fmark@awi.de

Teasing the capacities of cellular energy metabolism and its contribution to an organism’s overall energy budget apart by means of mitochondrial respirometry has experienced a rise in interest and associated studies over the past few years. With internationally standardized procedures and sophisticated titration protocols, we are able to take a detailed look into mitochondrial metabolism at individual respiratory complex level even of non-model organisms, including a plethora of diverse fish species. Yet many approaches have been translated from mammalian models and assumptions do not necessarily hold for fish and other ectothermal organisms. We therefore looked into the roles of oxygen partial pressure and substrate cross reactivity in the contributions of complex I and complex II respiration to overall OXPHOS in Polar cod (Boreogadus saida) and Antarctic eelpout (Pachycara brachycephalum). We furthermore compared different methods of mitochondrial extraction and enrichment for various tissues – with quite surprising results.

A8.10 THE EFFECT OF BODY MASS ON MITOCHONDRIAL EFFICIENCY IN BIRDS IS TISSUE DEPENDENT. A MACROPHYSIOLOGICAL APPROACH

Tuesday 4 July 2023 14:45

Jessica Barbe (University of Lyon, France), Julia Watson (University of Lyon, France), Damien Roussel (University of Lyon, France), Yann Voituron (University of Lyon, France)

jessica.barbe@univ-lyon1.fr

Body mass is known to be a fundamental driver of many biological traits, including metabolism. However, the body mass effect on mitochondrial energy transduction is still poorly understood and has mainly been described in mammals. Using 13 species of birds ranging from 15 g (finches) to 160 kg (ostrich), we demonstrated here a tissue dependence of the body mass effect on mitochondrial ATP production, oxygen consumption, and mitochondrial efficiency (ATP/O), with significant allometric patterns in skeletal muscle but absent in cardiac muscle. The allometric pattern was also found to be dependent upon metabolic intensities, with slopes corresponding to the lowest metabolic intensity being 2.5 times greater than the slopes corresponding to the highest metabolic intensity. This variation strongly suggests a higher degree of energetic flexibility in smaller birds compared to larger birds. This difference between muscle tissues is potentially linked to the difference in energetic demand expandability and the heavy involvement of skeletal muscle in thermoregulation.

A8.11 EXPOSURE TO AN UNCOUPLER OF OXIDATIVE PHOSPHORYLATION INCREASES WHOLE-ANIMAL OXYGEN CONSUMPTION IN THE INVASIVE LARVAL SEA LAMPREY.

Tuesday 4 July 2023 14:45

Hugo Flávio (Wilfrid Laurier University, Canada), Leonard D'Souza (Wilfrid Laurier University, Canada), Michael Wilkie (Wilfrid Laurier University, Canada)

hflavio@wlu.ca

In the Laurentian Great Lakes, invasive sea lamprey (Petromyzon marinus) contributed to massive declines in fisheries by parasitizing top predatory fishes. For sixty years, populations have been controlled by applying 3-trifluoromethyl-4-nitrophenol (TFM) to streams infested with larvae. TFM interferes with ATP production by disrupting the proton gradient across the inner mitochondrial membrane, uncoupling the electron transport chain from phosphorylation via the ATP synthase. As the proton gradient dissipates, electron transport chain activity increases, leading to greater mitochondrial O2 consumption. However, it remains unclear how TFM exposure affects whole-animal oxygen consumption (ṀO2). Using intermittent-flow respirometry, we demonstrate that whole-animal Ṁ O2 increases in a stepwise manner as TFM concentrations are increased. At the highest TFM concentration tested, ṀO2 plateaued at levels equivalent to the lamprey’s known maximum metabolic rate (MMR) following exhaustive exercise. At this concentration, oxidative phosphorylation was likely entirely disrupted, as the animals reached maximum rates of electron transport chain activity. Larvae died within 1-3h after reaching MMR, which likely coincided with depletion of anaerobic energy stores (glycogen, phosphocreatine). For animals exposed to non-lethal concentrations of TFM, ṀO2 rapidly declined upon transfer to clean water (i.e. recovery). However, ṀO2 remained above resting levels for 4-6h, likely related to replenishment of energy stores and restoration of homeostasis. We conclude that the effects of TFM on mitochondrial function are reflected in large changes in ṀO2 at the whole-animal level, and that respirometry could used to screen how non-target animals respond to TFM and similarly acting pesticides while reducing experimental lethality.

Tuesday 4 July 2023

14:45

Elisa Thoral (Lund University Department of Biology Section for Evolutionary Ecology, Sweden), Maria Correia (Lund University Department of Biology Section for Evolutionary Ecology, Sweden), Eskil Elmér (Lund University Department of Clinical Sciences Mitochondrial Medicine, Sweden), Imen Chamkha (Lund University Department of Clinical Sciences Mitochondrial Medicine, Sweden), Andreas Nord (Lund University Department of Biology Section for Evolutionary Ecology, Sweden)

A8.12 EFFECT OF INCUBATION TEMPERATURE ON MITOCHONDRIAL THERMAL SENSITIVITY AND REACTIVE OXYGEN SPECIES PRODUCTION DURING EARLY-LIFE DEVELOPMENT IN JAPANESE QUAIL

elisa.thoral@biol.lu.se

Thermal conditions experienced during early-life in birds have strong phenotypic and physiological effects in hatchlings and juveniles. Thus, an increase in the incubation temperature of eggs leads to accelerated embryonic growth and reduced neonatal metabolic rate while lower incubation temperature delays growth and increases metabolic rate. However, the reduction in growth rate in low incubation temperature is often less than predicted from the temperature drop alone, but the mechanisms underlying this counter-gradient adaptation are poorly understood. Moreover, incubation temperature-dependent changes in physiology have been interpreted as adaptive environmental matching of developmental and adult environments, but this remains speculative since no studies have formally tested this hypothesis. To study the mechanisms underlying counter-gradient adaptation of embryonic development, we measured the mitochondrial metabolism in heart and liver, two highly metabolic tissues of 13-day old Japanese quail embryos incubated at 36, 37.5 or 39°C, representative of the natural range of temperatures experienced by the eggs. Then, to test the environmental matching hypothesis, we measured the thermal sensitivity of mitochondrial respiration and reactive oxygen species production in the heart of embryos from different incubation temperatures. By linking these results with temperature dependent growth patterns from fertilization until hatching, this project will help to understand the capacity of embryos to respond to a thermallyvariable environment during development. This is a first step towards revealing the mechanisms by which developmental temperature programs temperature tolerance in adult birds.

A8.14 OMEGA-3 SUPPLEMENTATION AS AN EFFECTIVE STRATEGY TO ALLEVIATE IMIDACLOPRID INHIBITION OF MITOCHONDRIAL RESPIRATION IN HONEYBEES

Tuesday 4 July 2023 14:45

Hichem A. Menail (Université de Moncton, Canada), Robert Cormier (Université de Moncton, Canada), Florence Hunter-Manseau (Université de Moncton, Canada), Arianne Blanchard (Université de Moncton, Canada), Nicolas Pichaud (Université de Moncton, Canada)

eam5475@umoncton.ca

A8.13

MITONUCLEAR INTERACTIONS IMPACT RESPONSES TO METABOLIC AND REDOX STRESS IN DROSOPHILA MELANOGASTER

Tuesday 4 July 2023 14:45

Enrique Rodriguez (University College London, United Kingdom), Sahutchai Inwongwan (Department of Biology Faculty of Science Chiang Mai University, Thailand), Florencia Camus (University College London, United Kingdom), Nick Lane (University College London, United Kingdom)

enrique.rodriguez@ucl.ac.uk

Mitochondrial function depends on direct interactions between respiratory proteins encoded by genes in two genomes, mitochondrial and nuclear, which evolve in very different ways. Serious incompatibilities between these genomes can have severe effects on development, fitness and viability. The effect of subtle mitonuclear mismatches has received less attention, especially when subject to mild physiological stress. Using male and female fruit flies with different mitochondrial genomes but isogenic in their nuclear genes, we investigate how various stressors affect whole-animal and mitochondrial phenotypes, as well as metabolic pathways and gene expression. Flies fed either a high protein diet (HP), the glutathione precursor N-acetyl cysteine (NAC), or the NADH precursor nicotinamide riboside (NR) had sex, tissue, and genotype-specific responses to these stressors. Metabolomic results point to changes in TCA cycle flux, while respirometry analysis shows changes in substrate use and complex I function. Our results support the notion that subtle mitonuclear mismatches can lead to diverging responses to environmental stressors, undermining fitness in some cases, but surprisingly improving outcomes in other mismatched fly lines.

Pesticides are a major cause of honeybee colony losses that can deeply disrupt food supply due to pollination shortages. Among these, imidacloprid and glyphosate are the most widely used ones. Both are harmful to honeybees and at low concentrations they can hinder their metabolism. For that reason, a nutritional strategy is been investigated to mitigate the effects of pesticides on honeybees by using ahiflower-oil that is rich in stearidonic-acid (SDA, 18:4n3). The latter is a precursor of eicosatetraenoic-acid (EPA) and docosahexaenoic-acid (DHA) that are known to increase mitochondrial efficiency and longevity in different animal models. Specifically, we chronically exposed newly emerged worker bees to (i) imidacloprid (0.375 ng/µl), (ii) glyphosate (0.625 ng/µl), (iii) ahiflower-oil (5%) + imidacloprid and (iv) ahiflower-oil + glyphosate. Survival was recorded and after 25 days, mitochondrial respiration was measured. The results indicate that imidacloprid caused a significant decrease in complex-I respiration (36.43±4.49 pmolO2.s-1. mg-1 tissue) in comparison to control (73.46±6.57pmolO2.s-1.mg-1 tissue). However, ahiflower-oil supplementation restored respiration levels to some extent (ahiflower oil + imidacloprid group, 55.9±6.92 pmolO2.s-1.mg-1 tissue) which was then no longer significantly different from control. After the addition of succinate and G3P, respiration levels increased markedly and were similar between all groups. On the other hand, there were no significant differences between glyphosate exposed groups at any respiration state. Hence, our study indicates a detrimental effect of imidacloprid on mitochondrial respiration which can disrupt ATP production and demonstrates that both metabolic flexibility (the capacity to use different oxidative substrates) and ahiflower-oil can restore mitochondrial functions.

A8.15 CONTRIBUTION OF MITONUCLEAR GENOMES TO LOCAL ADAPTATION

Tuesday 4 July 2023 15:30

Florencia Camus (University College London, United Kingdom)

f.camus@ucl.ac.uk

Mitochondrial metabolism is regulated by a series of enzyme complexes within the mitochondrion, with their functioning being highly sensitive to the environment. Indeed, many studies have found that mitochondrial haplotype frequencies tend to associate with latitude and altitude, which has led to the hypothesis that mitochondrial genomes could contribute to local adaptation. Here we investigate this hypothesis by using the model system Drosophila melanogaster from the Australian eastern cline. Previous work has described two major mitochondrial

haplotypes, whose frequencies exhibit an opposing pattern of clinal variation – one predominating in the north (tropical), whereas the other more common in the south (temperate). Our work builds on this model, and we have created mitonuclear cybrid populations to test the contribution of both genomes to life-history traits and mitochondrial bioenergetics. I’ll present evidence for these intergenomic interactions being quite important contributors to local adaptation and species persistence.

A8.16 DOES THE THERMAL PREFERENCES OF ROTIFERS LECANE INERMIS AFFECT MITOCHONDRIAL BIOENERGETICS AT OPTIMAL AND SUBOPTIMAL TEMPERATURES?

Tuesday 4 July 2023 16:00

Agata Burzawa (Jagiellonian University, Poland), Katarzyna Potera (Jagiellonian University, Poland), Eugene Sokolov (University of Rostock, Germany), Inna Sokolova (University of Rostock, Germany), Aleksandra Walczyńska (Jagiellonian University, Poland)

agata.burzawa@doctoral.uj.edu.pl

Given the critical role of mitochondria in providing up to 90% of the cell's ATP, it is crucial to investigate how abiotic factors impact mitochondrial functioning under various environmental conditions. The present study aimed to identify how mitochondrial bioenergetic parameters respond to temperature shifts and whether these responses change under optimal vs. non-optimal thermal conditions. We also sought to determine whether organisms with differing thermal preferences display varying responses. To this end, we used clones of the rotifer Lecane inermis with established thermal preferences and exposed them to four thermal regimes: standard temperature, optimum temperature, low suboptimal temperature, and high supraoptimal temperature. We assessed mitochondrial response by measuring the routine respiration rate of the rotifers as well as the maximum rate of the electron transport system (indicative of ATP synthesis capacity) and the rate of proton leak (indicative of the mitochondrial maintenance cost). Our findings suggest that clones with different thermal preferences exhibit distinct responses across the examined temperatures. For all studied mitochondrial traits, these differences were particularly pronounced at the suboptimal temperatures, while at standard and optimal temperatures, the clones exhibited similar behaviors. Overall, our study highlights the role of mitochondria in an organism's frontline response to changing environmental conditions. These results provide insight into the patterns of plastic organismal response to acute environmental changes and may help inform efforts to protect and preserve vulnerable ecosystems

A8.17 SPAWNING ACTS AS A METABOLIC STRESSOR ENHANCED BY HYPOXIA IN A BROADCAST MARINE SPAWNER

Tuesday 4 July 2023 16:15

Inna M. Sokolova (University of Rostock Marine Biology Department, Germany), Md. Mahamudul Hasan Mredul (University of Rostock Marine Biology Department, Germany), Hui Kong (University of Rostock Marine Biology Department, Germany), Eugene P. Sokolov (Leibniz Institute for Baltic Sea Research, Germany)

inna.sokolova@uni-rostock.de

Coastal hypoxia is a frequent stressor for marine benthic organisms. While the effects of hypoxia on mitochondrial function and energy metabolism have been studied, the response of mitochondria during spawning events is poorly understood. To address this knowledge gap, we investigated the effects of short-term hypoxia (7 days) and spawning on mitochondrial respiration, reactive oxygen species (ROS) production, and tissue energy status in the marine mussel Mytilus edulis. Under normoxic conditions, post-spawning (72 h) recovery was associated with an increase in the phosphorylation (OXPHOS) rate of mussels' mitochondria, while hypoxia suppressed this response. ROS production decreased after spawning, regardless of the oxygen regime, indicating that M. edulis can prevent oxidative stress and mitochondrial damage during spawning. The energy reserves of the tissues not directly involved in spawning (the gill and the digestive gland) decreased in the immediate aftermath of spawning, highlighting the high energy cost. Unlike gametogenesis, which is supported by glycogen utilization, the energy costs of spawning appear to be driven mostly by lipid and protein breakdown. Furthermore, cellular energy allocation decreased 3 h after spawning, indicating moderate bioenergetic stress. While this allocation recovered after 72 h under normoxia, it did not recover in hypoxia. These findings suggest that a spawning event represents a bioenergetics challenge for broadcast spawners like M. edulis, demanding a higher energy flux. Moreover, the recovery of energy status disrupted by spawning may be delayed under low oxygen conditions.

A8.18 DYNAMIC DEFENSE? INTERTIDAL TRIPLEFIN SPECIES SHOW BETTER MAINTENANCE OF MITOCHONDRIAL MEMBRANE POTENTIAL THAN SUBTIDAL SPECIES AT LOW O2 PRESSURES

Tuesday 4 July 2023 16:30

Alice R Harford (University of Auckland, New Zealand), Jules B. L. Devaux (University of Auckland, New Zealand), Anthony J. R. Hickey (University of Auckland, New Zealand) ahar714@aucklanduni.ac.nz

Oxygen (O2) is essential for most eukaryotic life as it supports mitochondrial oxidative phosphorylation to supply ~90% of cellular adenosine triphosphate (ATP). Therefore O2fluctuations present a major stressor, with hypoxia leading to a cascade of detrimental physiological changes that alter cell operations and ultimately induce death. Nonetheless, some species episodically tolerate near anoxic environments, and have evolved mechanisms to sustain function even

during extended hypoxic periods. While mitochondria (mt) are pivotal in central metabolism, their role in hypoxia tolerance still remains illdefined. Given the vulnerability of the brain to hypoxia, mt function was tested in brain homogenates of three closely-related triplefin species with varying degrees of hypoxia tolerance (Foresterygion varium, Foresterygion lapillumand Bellapiscus medius). High-resolutionrespirometry coupled with fluorometric measurements of mt membrane potential (mtMP) permitted assessment of differences in mt function and integrity in response to intermittent hypoxia. Traditional steadystate measures of respiratory flux and mtMP showed no differences among species. However, in the transition to hypoxia, tolerant species B. medius and F. lapillum maintained mitochondrial membrane potentials at O2 pressures 7 and 4.4 fold lower than sensitive F. varium respectively, and exhibited slower rates of membrane depolarisation. The results indicate that dynamic oxic-hypoxic mt transitions underlie hypoxia tolerance in these intertidal fish.

A8.19 OSMOTOLERANCE REFLECTED IN MITOCHONDRIAL RESPIRATION OF POPULATIONS FROM THREE DIFFERENT HABITAT SALINITIES

Tuesday 4 July 2023 16:45

Amanda A. Wiesenthal (University of Rostock, Germany), Inna Sokolova (University of Rostock, Germany)

Amanda.wiesenthal@uni-rostock.de

Mussels from the Mytilus edulis species complex experience a salinity gradient from the North Sea into the Baltic Proper ranging from 32 psu to 5-6 psu. As osmoconformers, mussels adjust their internal osmolarity to match that of their surroundings. This adaptive strategy poses a significant challenge to the metabolic machinery of the mussels, including their mitochondria. We hypothesised that the osmotic optima for the mitochondrial function of mussels matches the prevailing habitat salinity. To test this hypothesis, mussels from three populations along the salinity gradient were assessed: north Baltic Sea (M. trossulus zone), south Baltic Sea (transition zone) and North Sea (M. edulis zone). The mitochondrial performance curve was generated by measuring respiration of isolated hepatopancreas mitochondria in the resting (LEAK) and actively phosphorylating (OXPHOS) states (indicative of the futile proton leak and ATP synthesis capacity, respectively) at a range of osmotic concentrations. The habitat salinity shift from the north to the south Baltic Sea was reflected in a shifted peak performance of the mitochondria towards a higher osmotic concentration. Mitochondria from North Sea Mytilus exhibited a better performance at higher osmotic concentrations and showed a wider tolerance range than their Baltic Sea congeners. The osmotic concentration also affected mitochondrial coupling efficiency, reserve electron transport system capacity and reserve cytochrome c capacity.

Baltic Sea populations appear to have traded off an adaptation to low salinities for a narrower mitochondrial tolerance range resulting in a more specialized mitochondrial phenotype, while North Sea populations have mitochondria with a more general functioning phenotype.

POSTER SESSIONS

Wednesday 5 July 2023

17:15-19:15

A8.20 MITONUCLEAR INTERACTIONS IN A CHANGING WORLD

Wednesday 5 July 2023

POSTER SESSION

Stefano Bettinazzi (University College London, United Kingdom), Tom Allison (Monash University, Australia), Arthur Combeaud (University College London, United Kingdom), Damian K Dowling (Monash University, Australia), Nick Lane (University College London, United Kingdom), Florencia Camus (University College London, United Kingdom)

s.bettinazzi@ucl.ac.uk

Mitochondria are central hubs for energy transduction, thus major determinants of all aspects of fitness. Mitochondrial function is however vulnerable as it depends on components coded by two genomes: the mitochondrial and the nuclear DNA, which must interact harmoniously to preserve bioenergetic efficiency. Consequently, intergenomic mismatch could severely impact individual phenotypes, with repercussion on adaptation and biodiversity. Extreme environmental changes are now occurring at an unprecedented pace, with large consequences on species persistence and distributions. Introgression events between once-separated populations are thus expected to increase, and this has the potential to unmask genetic incompatibilities and manifest as hybrid breakdown. Temperature and diet modulation are also expected to place a burden on mitochondrial function, potentially aggravate the situation. The aim of this project was to investigate the contribution of mitonuclear genomes to population adaptive phenotypes in the face of climate uncertainty. To simulate the consequences of mitonuclear mismatch in naturally interbreeding populations, we generated a full-factorial mitonuclear panel of Drosophila melanogaster, including locally-adapted native strains and reciprocal mismatched lines. The combined impact of mitonuclear genomes, temperature modulation and nutrition was examined on mitochondrial functions and organismal fitness. Results indicate that intergenomic epistasis can have a strong physiological impact at different level of biological hierarchies: from cells to individuals, and that ecological stressors stemming from a mutating world could exacerbate these incompatibilities, amplifying fitness breakdown in admixed cybrid populations.

A8.21 THE MAGNITUDE OF LIPID LOSS DURING SHORTTERM FOOD DEPRIVATION IN FRESHWATERECTOTHERMS

IS MEDIATED BY MITOCHONDRIAL EFFICIENCY

Wednesday 5 July 2023 POSTER SESSION

Neal J Dawson (University of Glasgow, United Kingdom), Darryl McLennan (University of Glasgow, United Kingdom), Agnieszka Magierecka (University of Glasgow, United Kingdom), Caroline Millet (University of Glasgow, United Kingdom), Neil B Metcalfe (University of Glasgow, United Kingdom)

neal.dawson@glasgow.ac.uk

Most fish undergo periods of natural food deprivation as a result of seasonalfluctuations in food supply, non-feeding spawning, or large migration events. Short-termfasting events involve the mobilization of available metabolite reserves where body protein istypically conserved at the expense of stored carbohydrate and lipids. The rate at which thesemetabolic reserves are used up is thought to be dictated by an individual’s mitochondrialefficiency (i.e., the efficiency with which mitochondria convert these energy-rich moleculesinto ATP). We tested this hypothesis by examining the relationship between mass, lipid loss,and mitochondrial function in an age and size-matched sample of minnows (Phoxinusphoxinus) that were experimentally fasted over a two week period. We used morphologicalmeasurements to estimate the lipid content of the fish before and after the food deprivationtrial. Fish which had the lowest percentage mass loss showed the greatest remaining lipidcontent at the end of the two week period. We also found evidence that mitochondrialphosphorylation efficiency was positively correlated with relative remaining lipid reservesafter two weeks of food deprivation. Whereas, percentage lipid loss showed a negativecorrelation with mitochondrial efficiency, implying that the most efficient fish experiencedthe least amount of lipid loss. Therefore, individual variation in muscle mitochondrialefficiency seems to mediate the rate of depletion of metabolite stores, with less efficientindividuals using up their lipid reserves more rapidly. Together, this suggests that individualswith more efficient mitochondria may be better at surviving under environmentally-inducedperiods of food deprivation.

A9 SPECIES INTERACTIONS AND THEIR ROLE IN EXPERIMENTAL PHYSIOLOGY: BRINGING BACK THE BIO

A9.1 THE COMPLEXITIES OF THE FISH INTESTINAL MICROBIOME: INSIGHTS INTO DIVERSITY, FUNCTIONS, AND INFLUENTIAL FACTORS. WHERE DO WE GO FROM HERE?

Thursday 6 July 2023 09:00

Carol Bucking (York University, Canada)

cbucking@yorku.ca

The fish intestinal microbiome has emerged as a key player in fish health and nutrition over the last decade. Indeed, the intestinal bacteria inhabiting the gut play a crucial role in the digestion, metabolism, and immune defense of fish. Recent advancements in high-throughput sequencing technologies have shed light on the specific microbial taxa present in the fish intestine and their functions. However, the composition and diversity of the fish intestinal microbiome are also influenced by a range of factors including diet, host genetics, and environmental conditions. Here I will discuss the current state of knowledge regarding the fish intestinal microbiome, including its composition, functions, and interactions with the host. In particular I will compare and contrast freshwater and saltwater fish, as well as carnivorous vs omnivorous vs herbivorous fish. The results will be discussed through the lens of our current knowledge and some avenues to go next.

A9.2

HOW DOES FORAGING PARADIGM CONSTRAIN OUR UNDERSTANDING OF ENERGY, MACRONUTRIENT, AND FITNESS CONSEQUENCES OF ANIMAL DIETS?

Thursday 6 July 2023 09:30

Ashlee J Mikkelsen (University of Souht-Eastern Norway, Norway), Keith A. Hobson (University of Western Ontario, Canada), Agnieszka Sergiel (Polish Acadmey of Sciences, Poland), Anne G Hertel (Ludwig Maximilians University of Munich, Germany), Nuria Selva (Polish Academy of Sciences, Poland), Andreas Zedrosser (University of South-Eastern Norway, Norway)

ashlee.mikkelsen@usn.no

Understanding biological adaptations to environmental and physiological challenges to resource acquisition and investment is fundamental to biology, yet due to mathematical and experimental limitations, theoretical, experimental, and applied studies rarely come to the same conclusions. We used a well-studied omnivore with a wide distribution, the brown bear (Ursus arctos), to illustrate how assumptions in the theoretical, experimental, and methodical frameworks of biology can result in different conclusions regarding physiological limitations, morphology, and life-history. We developed three hypothesized diets of five common foods based on models derived from the literature based on: 1) energetic efficiency, 2) morphology, and 3) experimental feeding trials. We then compared predictions to field estimates of diet from a wild population of brown bears using stable isotopes values of carbon and nitrogen (δ13 C, δ15 N) and Bayesian mixing models. We then used published nutritional information to estimate the percent protein, carbohydrates, and lipids in brown bear diets. Bears primarily consumed berries (88–92%), followed by ants (5–8%), and moose (3–4%). Protein was lower than expected for this species and predicted by models based on morphology experimental feeding. While diets most closely resembled predictions from a model that optimized caloric efficiency, none of our models fully captured the nuances of brown bear biology. Across all systems, it is critical to understand how organisms obtain and use the resources they consume through diet to better understand biological adaptations to environmental and physiological challenges. Yet our results highlight the limitations of simplified models to explain complex communities and processes.

ORGANISED BY: TAMZIN BLEWETT (UNIVERSITY OF ALBERTA), SANDRA BINNING (UNIVERSITY OF MONTREAL)

A9.3 INTERSPECIFIC INTERACTIONS ALTER THE METABOLIC COSTS OF CLIMATE WARMING

Thursday 6 July 2023 09:45

Lesley A Alton (Monash University, Australia), Vanessa Kellermann (Monash University, Australia)

lesley.alton@monash.edu

Climate warming is expected to increase the energy demands of ectotherms by accelerating their metabolic rates exponentially. However, this prediction ignores environmental complexity such as species interactions. To better understand the metabolic costs of climate change for ectotherms, we reared three Drosophila species in either single-species or two-species cultures at different temperatures and projected adult metabolic responses under an intermediate climate-warming scenario across the global range of Drosophila. We determined that developmental acclimation to warmer temperatures can reduce the energetic cost of climate warming from 39% to ~16% on average by reducing the thermal sensitivity of metabolic rates. However, interspecific interactions among larvae can erode this benefit of developmental thermal acclimation by increasing the activity of adults that develop at warmer temperatures. Thus, by ignoring species interactions we risk underestimating the metabolic costs of warming by 3–16% on average.

A9.4 SOCIALITY AND ANTHROPOGENIC STRESSORS: HOW BIOTIC FACTORS INFLUENCE COPPER TOXICITY

Thursday 6 July 2023 10:00

Sienna L Overduin (University of Alberta, Canada), Sienna L Overduin (University of Alberta, Canada), Jerem De Bonville (Université de Montréal, Canada), Robert A Griffin (University of Alberta, Canada), Michael R Skeeles (Deakin University, Australia), Hanna Scheuffele (Deakin University, Australia), Timothy D Clark (Deakin University, Australia), Tommy Norin (Technical University of Denmark, Denmark), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway), Tamzin A Blewett (University of Alberta, Canada)

soverdui@ualberta.ca

Many animals benefit from group living. Advantages include greater protection and foraging, in addition to social buffering (i.e., reduced stress concurrent with exposure to members of the same species). However, sociality is not the only variable fish encounter; changes in environmental parameters due to climate change and anthropogenic pollutants are damaging aquatic ecosystems. To date, minimal research has been performed to expand our understanding of the nexus between sociality and toxicity. Therefore, we tested the effects of copper (Cu), a potent aquatic toxicant, on the Swedish marine threespine stickleback (Gasterosteus aculeatus) under different social contexts. In particular, we sought to understand whether the social stress of isolation would increase the resting and maximal oxygen uptake rate (ṀO2) of stickleback leading to greater accumulation of Cu. To determine ṀO2 wild caught fish were randomly placed in one of four treatment groups within respirometry chambers: isolated control (single fish, no added Cu), paired control (two fish, no added Cu), isolated Cu (single fish, nominally 300 µg/L of Cu), and paired Cu (two fish, 300

µg/L nominally of Cu). Fish totalled 40 hours in respirometers with chasing occurring after 22 hours for maximal ṀO2. All fish were then euthanized and dissected with the gill, intestine, liver, and carcass assayed for Cu accumulation. The importance of understanding how sociality in fish alters the response to a given toxicant is rarely if ever investigated, but the social structure, and its role in fish metabolic rate and homeostasis cannot be dismissed.

A9.5 SOCIAL BEHAVIOUR AFFECTS THERMAL SENSITIVITY IN AN ISOGENIC AMPHIBIOUS FISH

Thursday 6 July 2023 10:15

Suzie Currie (Acadia University, Canada), Claire A Allore (Acadia University, Canada), Chloe A Melanson (Universite de Moncton, Canada), Simon G Lamarre (Universite de Moncton, Canada)

suzie.currie@acadiau.ca

In our effort to bring the BIO back into our experimental research, we have been studying how an animal’s social environment affects how they respond to their physical environment and specifically, environmentally relevant increases in temperature. Using the isogenic and amphibious mangrove rivulus fish (Kryptolebias marmoratus), we have shown that social stimulation changes how they respond to environmentally relevant high temperatures but the physiological mechanisms underlying these socially-influenced thermal responses are unknown. We tested the overarching hypothesis that sociality (e.g., experience, status) will influence how fish sense temperature. Temperature perception is facilitated through transient receptor potential (TRP) ion channels. We used capsaicin, a specific agonist of the TRP vanilloid subtype 1 (TRPV1) to induce chemical heat and measured the capsaicin concentration at which control and socially-stimulated fish emerged from water. We determined that socially experienced and socially subordinate fish required significantly higher capsaicin concentrations to elicit an emersion response compared to their naïve or dominant counterparts, respectively. This finding suggests that sociality desensitizes TRPV1 channels and alters thermal perception. A change in temperature perception could have dramatic consequences on how fish will cope with climate warming underscoring the importance of understanding biotic interactions when predicting how animals will respond to their physical environment.

A9.6 PRELIMINARY RESULTS: MECHANO-

IN JUVENILE DICENTRARCHUS LABRAX

Thursday 6 July 2023 11:00

Mishal Cohen-Rengifo (Ifremer, France), David Mazurais (Ifremer, France), Marie-Laure Begout (Ifremer, France)

mishal.cohen@ifremer.fr

Correct functioning of the sensory channels of vision, olfaction, audition and mechanosensation modulates predator-prey interactions and

ACOUSTIC AND VISUAL RESPONSES TO A PREDATOR UNDER OCEAN WARMING AND ACIDIFICATION

determines the success of antipredator responses. These channels are known to be sensitive to climate change in some marine fish. If ocean warming and acidification alter the sensory ability of fish to detect a predator and avoid it, community dynamics can be affected. We investigated whether mid-term exposure to warming and acidification alters the visual or mechano-acoustic responses to a predator in juvenile European sea bass, Dicentrarchus labrax. Behavioural kinematic variables were measured after a visual or a mechano-acoustic challenge which mimicked either an overflying bird or a bird swoop attack, respectively. Cue sensory perception was robust as fish of every treatment elicited precautionary and escape responses to the cue. Antipredator response varied according to the level of threat with greater responses elicited after the swoop attack. Warming alone or in combination with acidification had a strong effect on escape response, but treatments seems to not significantly impact antipredator response. Our results highlight the difficulties one encounters when tackling such multistressor and behavioural approach. Deciphering the role of each factor (including random ones), and the effects of inter-individual variability is challenging from the perspective of species resilience to climate change evaluation.

A9.7

RELATE TO PARASITE INFECTION?

Thursday 6 July 2023 11:30

Jeremy De Bonville (Université de Montréal, Canada), Sandra A. Binning (Université de Montréal, Canada)

jeremy.de.bonville@umontreal.ca

Ectotherms are particularly vulnerable to climate change as their body temperature is regulated by their external environment. Sudden changes in temperature caused by heat waves can cause rapid shifts in the aerobic capacity of fishes, in turn affecting their ability to maintain normal ecological activities. In addition, rising temperatures are altering host-parasite relationships such that organisms may have to live in a world with higher temperatures and more infections. How these two concomitant stressors interact to affect animal performance remains unclear. For instance, increasing temperature and parasites may have opposing effects on maximum swimming speeds, where higher temperatures may increase some measures of performance, whereas higher parasite loads may decrease performance. We acclimated wild caught, naturally infected pumpkinseed sunfish (Lepomis gibbosus) to 3 temperatures (20, 25 and 30°C) and measured their maximum swimming speed (Ucrit ) and metabolic performance in a Steffensentype swimming respirometer. Fish acclimated to warmer temperatures swam longer before exhaustion but there was no strong relationship between swimming performance and parasite infection across the 3 acclimation treatments. However, when controlling for temperature, we found that fish with fewer parasite cysts on their fins and body surfaces had higher Ucrit , whereas fish with more cysts swam for shorter periods. Our results suggest that some infections may affect host swimming performance through increased drag, and highlight the need to include parasites in experimental physiology studies on wild animals. Considering multiple biotic stressors when measuring animal performance is important as it may reveal hidden relationships that would be missed otherwise.

A9.8 THE HOST AND BEYOND: RESPONDING TO AN INFECTION AFFECTS EVERYONE ELSE

Thursday 6 July 2023 11:45

Patricia C. Lopes (Chapman University, United States) lopes@chapman.edu

When invaded, the body triggers a series of reactions to neutralize and destroy the invader. This host response, while seemingly localized, can then have consequences that expand within and beyond the boundaries of the host’s body, with far-reaching ecosystem-level implications. In this talk, I will explore the different ways in which the host response affects other organisms that live within or around the infected host, and the implications of these effects for how we study disease responses.

BRINGING BACK PARASITES : DOES THE SWIMMING PERFORMANCE OF PUMPKINSEED SUNFISH ACROSS DIFFERENT ACCLIMATION TEMPERATURES

A10 FROM BACTERIA TO WHALES: USING SIZE SPECTRA TO MEASURE GLOBAL CHANGE

ORGANISED BY: VOJSAVA GJONI (UNIVERSITY OF SOUTH DAKOTA), JIM JUNKER (LOUISIANA UNIVERSITIES MARINE CONSORTIUM)

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A10.1 EFFECTS OF AGROCHEMICAL INTENSIFICATION AND SPATIAL ISOLATION ON THE SIZE SPECTRA OF TEMPORARY FRESHWATER COMMUNITIES

Wednesday 5 July 2023

POSTER SESSION

Rodolfo M Pelinson (São Paulo State University (Unesp), Brazil), Victor Saito (Federal University of São Carlos (UFSCar), Brazil), Luis Schiesari (University of São Paulo (USP), Brazil)

rodolfopelinson@gmail.com

The management of agrochemicals has become a cornerstone of agriculture, allowing it to expand over many terrestrial ecosystems. Such expansion altered the connectedness of aquatic habitats to organisms with complex life cycles by frequently increasing the number of temporary ponds in interfluves. Here, we investigated how spatial isolation and agrochemical contamination affect the size spectra of macroinvertebrates and amphibians in these ecosystems. We conducted a field experiment simulating realistic scenarios of agrochemical contamination at different levels of spatial isolation. We constructed forty-five 1,200-L artificial ponds in a savanna landscape in Brazil at three distances from a source wetland (30 m, 120 m, and 480 m). Ponds were spontaneously colonized by aquatic insects and amphibians and treated with no agrochemicals (control), fertilizers (as in managed pastures), or fertilizers and a single pulse of the insecticide fipronil and the herbicide 2,4-D (as in sugarcane fields) following realistic dosages and application schedules. We found that isolated communities exhibited greater intercepts for mass-abundance relationships, meaning that isolated ecosystems have more energy allocated in small individuals. We also found that communities treated with insecticides deviate from the classic linear negative mass-abundance relationship. These communities exhibited positive slopes in contrast to negative ones in the other treatments, meaning that most of the energy in these ecosystems were allocated in large abundant organisms that are resistant to insecticide application, such as amphibians. These results have direct consequences for the emergence of insects and amphibians affecting aquatic and terrestrial ecosystem services.

A10.2 WORLDWIDE BODY SIZE DISTRIBUTIONS OF FRESHWATER CRUSTACEAN COMMUNITIES: ARE GLOBAL MECHANISMS OVERRIDING LOCAL ONES?

Wednesday 5 July 2023 POSTER SESSION

Vojsava Gjoni (University of South Dakota, United States), Rosalie Bruel (French Biodiversity Agency, France) vojsava.gjoni@usd.edu

Body size is a key functional trait that affects many physiological and ecological processes. Among ectotherms, body size patterns are strongly influenced by temperature variation (temperature-size rule). Consequently, climate change is likely to alter body size patterns affecting ecosystem function, particularly in size-structured aquatic communities. However, predicting the impacts of climate change on aquatic communities is challenging due to the multiple interacting factors involved (e.g., exploitation, nutrient enrichment). Hence, there is a need to collect detailed global data on body size of keystone organisms (i.e., zooplankton) and environmental characteristics of their habitats. The ZooSize project was launched in 2021 to create a global database of individual crustacean zooplankton body size measurements along with environmental factors from an array of freshwater lakes to address the following questions: (1) How do zooplankton community size metrics change across lake thermal regions? (2) How do local environmental factors affect the body size-temperature relationship within and across thermal regions? We hypothesise that warmer regions and greater levels of planktivory and nutrient enrichment will lead to greater relative abundance of small-bodied zooplankton and lower community size variation. So far, we have received data from over 100 freshwater lakes distributed globally covering a wide range of environmental variables. Our unique and comprehensive dataset will provide critical insights into the impacts of climate change on global patterns of zooplankton community size structure and how body size can be used as an indicator of ecological status in lake conservation and restoration.

A10.3 EFFECTS OF FOOD AVAILABILITY AND GROWTH VARIATION ON ONTOGENETIC METABOLIC SCALING IN ZEBRAFISH

Wednesday 5 July 2023 POSTER SESSION

Alexander Rosén (Danish Technical Universety, Denmark), Tommy Norin (Danish Technical University, Denmark)

alero@aqua.dtu.dk

The steepness with which metabolic rate scales with body mass has been widely researched and debated due to its fundamental importance for size-dependent energetics and ecosystem dynamics. Little work has however been devoted to examining scaling on a within-individual (ontogenetic) level and what factors can affect this. Previous work has shown that variation in the steepness of ontogenetic scaling of standard (maintenance) metabolic rate (SMR) correlates with variation in growth rate among individuals of one species (brown trout) fed restricted, while the relationship was absent in another species (cunner) fedad libitum. Thus, to understand if the relationship between ontogenetic metabolic scaling and growth rate is dependent on environmental food availability, we performed an experiment with 3 x 30 zebrafish kept individually from the larval stage to adulthood and fed low, medium, or high food rations. SMR and fish mass were repeatedly measured for all individuals as they grew, and ontogenetic metabolic scaling and growth rate calculated. While the experiment is still ongoing, our preliminary data suggest that there are substantial differences between ontogenetic scaling both within and between treatment groups. These differences are expected to become even more pronounced as the experiment finishes. A better understanding of what causes variation in how metabolic rate scales ontogenetically should help shed light on the variation in metabolic scaling that is observed at other levels of biological organization, such as across individuals or species, since natural selection works on individuals.

A10.4 THE ORGANIZATION OF SIZESTRUCTURED FOOD WEBS ALONG TEMPERATURE GRADIENTS

Thursday 6 July 2023 14:30

Victor S Saito (Universidade Federal de São Carlos, Brazil), Daniel Perkins (University of Roehampton, United Kingdom), Giovanna Collyer (University of Tokyo, Japan), Pavel Kratina (Queen Mary University, United Kingdom)

victor.saito@gmail.com

One of the pure definitions of ecology is the study of how organisms interact with themselves and with their surrounding environment and yet we are far from understanding the rules of trophic interactions in nature. One emerging generalization is the fact that rarer larger animals eat abundant smaller ones creating the pattern known as the size spectrum. This pattern is generally depicted as a double-log linear association between population abundance and individual biomass and could represent energy flowing imperfectly along the food web. In this talk, I will discuss how temperature, the master driver of organisms' metabolism, changes with latitude and so, should influence size spectra globally in ectotherms in several ways. First, I will describe hypotheses on how metabolism modulates stochastic biological events that scale to control size spectra. Next, I will indicate how connectance between adjacent communities could modify size spectra via metacommunity

dynamics, and finally, I will present preliminary analyses from tropical and temperate stream communities addressing these ideas. The study of size spectra from the metacommunity perspective, bringing together deterministic and stochastic processes operating at multiple spatial scales, may help us advance our understanding of how energy flows in natural ecosystems.

A10.5 GROWTH AND MORTALITY AS CAUSES OF VARIATION IN METABOLIC SCALING AMONG TAXA AND TAXONOMIC LEVELS

Thursday 6 July 2023 25:00

Tommy Norin (DTU Aqua: National Institute of Aquatic Resources | Technical University of Denmark, Denmark)

tnor@aqua.dtu.dk

Metabolic rate (MR) usually changes (scales) out of proportion to body mass (BM) as MR = aBMb , where a is a normalisation constant and b the scaling exponent that reflects how steep this change is. This scaling relationship is fundamental to biology, but over a century of research has provided little consensus on the value of b, and why it appears to vary among taxa and taxonomic levels. Here, I show that individual variation in fish growth under naturally restricted food availability can explain variation in within-individual (ontogenetic) b for standard metabolic rate (SMR) of brown trout (Salmo trutta); the fastest growers had the steepest metabolic scaling, and within-individual b varied much more widely than previously assumed from work on different individuals or different species, from –1 to 1. The negative b for some individuals was caused by reductions in metabolic rate, likely to maintain positive growth, which resulted in a mean within-individual b that was significantly lower than the across-individual (‘static’) b, a difference that also existed for another species, cunner (Tautogolabrus adspersus). I also show that across-species (‘evolutionary’) bSMR of 134 fishes is significantly steeper than the mean ontogenetic b for the trout and cunner. I hypothesise that the steeper evolutionary than ontogenetic scaling for fishes could arise as a by-product of natural selection for fast-growing individuals with steep metabolic scaling early in life, where size-selective mortality is high. I support this by showing that bSMR tends to increase with natural mortality rates of fish larvae within taxa.

A10.6 THE SIZE-MORTALITY SPECTRUM: TOWARDS A ‘MORTALITY THEORY OF ECOLOGY’

Thursday 6 July 2023 15:15

Douglas S Glazier (Douglas Stewart Glazier, United States)

glazier@juniata.edu

Size-abundance relationships have often been explained by sizerelated variation in metabolic rate. It is often assumed that metabolic rate drives the rates of various biological and ecological processes, including demographic parameters such as population growth rate and mortality rate. Here, I discuss an alternative (complementary) approach that considers mortality rate as the primary driver of the bodysize scaling of population growth rate and various physiological and

life-history traits. According to a proposed ‘size-mortality spectrum’, small vulnerable organisms are subject to higher mortality rates than are large protected organisms. The negative size-scaling of mortality rate, in turn, drives negative scaling of rates of individual development and reproduction and maximal population growth rate (rmax ). A new ‘mortality theory of ecology’ may revamp our interpretations of size-abundance relationships and how they are influenced by various physiological and ecological factors.

A10.7 HOW METABOLIC PLASTICITY AFFECTS COMMUNITY SCALING PATTERNS

Thursday 6 July 2023 15:30

Giulia Ghedini (Instituto Gulbenkian de Ciência, Portugal)

gghedini@igc.gulbenkian.pt

The distribution of biomass across organisms of different sizes is an important feature of ecological communities. Small organisms are typically more abundant than larger ones, and these predictable patterns are usually explained by the size-dependence of metabolism. However, it remains unclear to what extent physiological constraints on energy use influence the structure of communities because both size and metabolism are plastic to the environment. I will present work that explores variation in metabolism-size scaling relationships in response to competition and environmental change in marine phytoplankton. I then will discuss how this metabolic plasticity influences the size spectra and metabolic fluxes of communities that are not at equilibrium.

A10.8 THE ROLE OF BENTHIC-PELAGIC COUPLING ON SIZE-STRUCTURED FOOD WEBS: AN IN-SITU PHYTOPLANKTON AND ZOOPLANKTON

ENCLOSURE EXPERIMENT

Thursday 6 July 2023 15:45

between the slopes of the independent assemblages but tended to be driven by the larger sizes of the zooplankton. The combined phytozooplankton CSS slopes differed across all treatment combinations and was steepest in the disconnected and shallowest in the partiallyconnected. Interestingly, there were macroinvertebrates present in the fully-connected treatment that were not present in the others resulting in lower food web capacity and likely steepening the slope analogous to fishing. Decoupling the benthic and pelagic zones decreased the efficiency of the zooplankton assemblage but had no effect on the phytoplankton.

A10.9 WHY ARE THERE NOT MORE PREDATORS? RECONCILING PREDATORPREY BIOMASS SCALING AND SIZE SPECTRUM THEORY

Thursday 6 July 2023 16:30

Daniel M Perkins (University of Roehampton, United Kingdom)

daniel.perkins@roehampton.ac.uk

The distribution of biomass along food chains is a key measure in ecology and tends to form a characteristic ‘pyramid’ pattern with greater biomass at low trophic levels (e.g. herbivores) than at high trophic levels (e.g. carnivores). Recent work has shown remarkable regularity in how pyramid shape changes across locations in both aquatic and terrestrial systems. Specifically, a sub-linear (near three-quarter-power) scaling pattern emerges between predator biomass and the biomass of their prey – that is, biomass pyramids tend to become more bottom heavy as prey biomass increases. This broad-scale empirical pattern is compatible with a general form of density dependence that holds among complex feeding interactions across levels of organization, irrespective of ecosystem type.However, this systematic change in trophic structure appears to be at odds with the notion of universal size spectra, whereby biomass is approximately evenly distributed across logarithmic body size classes (e.g. from bacteria to whales). This talk will attempt to reconcile these two pervasive macroecological patterns (and associated bodies of theory) and discuss implications for assessing the impacts of environmental change in natural systems.

brent.murry@mail.wvu.edu

Community size-spectra (CSS) are an effective approach of assessing community size-structure and respond in a predictable manner to ecological drivers. There has been relatively little work, however, evaluating how habitat connectivity effects CSS. We studied the role of benthic-pelagic coupling on CSS using a series of experimental enclosures within a natural fishless wetland. The enclosures encompassed three treatments (1) connected, where there was no limitation between the benthic and pelagic zones, (2) disconnected, where there was a solid barrier between the zones (isolating only the pelagic zone), and (3) a partially-connected treatment (38µm mesh) that allowed water and dissolved nutrients to pass but not organisms. We sampled plankton from each enclosure over 37 days. Phytoplankton CSS were highly consistent among treatments and showed consistently steeper CSS slopes than zooplankton when separate. Zooplankton CSS differed among treatments, the disconnected treatment was significantly steeper than the connected and partially-connected. The slopes of the combined phyto-zooplankton CSS were intermediate

A10.10 THE EFFECTS OF STREAM RESTORATION ON MACROINVERTEBRATE SIZE SPECTRA ACROSS 30 YEARS.

Thursday 6 July 2023 17:00

Justin PF Pomeranz (Colorado Mesa University, United States), Taylor Beach (Colorado State University, United States), Lindsey Muniz (Colorado State University, United States), Will H Clements (Colorado State University, United States)

jpomeranz@coloradomesa.edu

Size spectra describe the declining abundance of individuals with increasing body size in natural communities. This pattern is relatively consistent across ecosystems, habitats, and body size ranges. This consistency has led to the proposal of characterizing size spectra relationships as a proxy variable for overall community health or status. Empirical evidence suggests that

Brent A. Murry (West Virginia University, United States)

size spectra do respond to anthropogenic disturbances, including over fishing in marine systems, and legacy effects of acid mine drainage in streams. However, it remains unclear if size spectra relationships respond beneficially to restoration activities aimed at improving biotic and abiotic conditions. Here, we analyze stream benthic macroinvertebrate community data collected over 30 years from sites which have received extensive restoration actions in order to improve water quality. We document consistent improvements in water quality through time. Likewise, size spectra parameters from restored streams consistently changed through time and approach reference conditions. Our results support the use of size spectra in biomonitoring applications. Likewise, our results are the first documented example of size spectra improving in reponse to restoration actions.

A10.11 POLLUTION ACCENTUATES THE EFFECTS OF WATER DIVERSION ON RIVER FOOD WEB ENERGY FLUXES, BUT DOES NOT ALTER ENERGY TRANSFER EFFICIENCY

Thursday 6 July 2023 17:15

Ioar De Guzman (University of the Basque Country, Spain), Jose M. Montoya (Centre for Biodiversity Theory and Modelling Theoretical and Experimental Ecology Station French N, France), Arturo Elosegi (University of the Basque Country (UPVEHU), Spain), Ana Victoria Perez-Calpe (University of the Basque Country (UPVEHU), Spain), Daniel Von Schiller (University of Barcelona, Spain), Jose M. González (Rey Juan Carlos University, Spain), Aitor Larrañaga (University of the Basque Country (UPVEHU) Spain, Spain)

mirenioar.deguzman@ehu.eus

Water diversion and pollution are two pervasive stressors for river ecosystems that often concur. Although, the individual effects of both stressors on stream river communities and energy transfer across the food webs are well described, their joint effects still remain unknown. We hypothesised that nutrient pollution would cause a moderate increase in herbivory, and water diversion, a strong reduction in detritivory whereas their joint effect would reduce invertebrate abundance and diversity, as well as total energy fluxes. We also expected a shift in size spectra slopes in moderately polluted rivers, related to increased energy transfer between trophic levels, but not with water diversion. For this, we selected four rivers in a range of pollution impacted by similar water diversion schemes and compared food webs upstream and downstream of their diversion weirs. Water diversion reduced the stock of detritus, whereas nutrient pollution promoted biofilm stock. Moreover, water diversion promoted heterogeneity of community composition, and reduced total energy fluxes and detritivory. Water pollution, on the other hand increased the homogeneity of invertebrate communities and increased herbivory and carnivory. However, size spectra did not show strong signs of perturbation. The energy transfer efficiency did not vary with the stressors, but the intercept of primary consumers size-spectra decreased with diversion. Our study points that water diversion and moderate pollution, alone and in combination, are able to modify energy pathways, but do not alter the energy transfer efficiency in riverine communities.

A10.12 LATITUDINAL PATTERNS OF SIZE SPECTRA ACROSS MARINE AND FRESHWATER ECOSYSTEMS: VALUABLE INSIGHTS FROM A SYSTEMATIC REVIEW

Thursday 6 July 2023 17:30

Ignasi Arranz (Universidad Rey Juan Carlos, Spain), Charlotte Evangelista (Université de Pau des Pays de l'Adour and University of California., France), Teofana Chonova (Swiss Federal Institute of Aquatic Science and Technology, Switzerland), Giovanna Collyer (The University of Tokyo, Japan), David Cunillera-Montcusí (Universitat de Barcelona Universidad de la República and University of Girona, Spain), Jorge García-Girón (University of Oulu and University of León, Spain), Carmen García-Comas (Institut de Ciències del Mar, Spain), Ioar De Guzman (University of the Basque Country, Spain), Aitor Larrañaga (University of the Basque Country, Spain), Daniel Perkins (University of Roehampton, United Kingdom), Justin Pomeranz (Colorado Mesa University, United States), Victor Saito (Federal University of São Carlos, Brazil), Javier Sánchez-Hernández (Universidad Rey Juan Carlos, Spain), Zeynep Ersoy (Universitat de Barcelona and Institut de Recerca de la Biodiversitat, Spain)

ignasiarranz@gmail.com

The size spectrum (hereafter SS) is a universal inverse relationship between abundance (or biomass) of individuals relative to their body size. SS research has provided valuable insights into the aquatic food web structure, especially in the context of anthropogenic impacts. Although SS patterns have been analysed for ecosystems and taxa individually, we still lack a global synthesis across ecosystems and taxonomic groups. Such a synthesis will be key to (i) identifying common responses to environmental drivers among aquatic ecosystems and (ii) assessing the main drivers of SS across different taxonomic groups. Using a unique dataset of SS parameters collected from peerreviewed and grey literature, we assess the responses of SS parameters across trophic levels, bioregions, and aquatic ecosystems in response to latitudinal gradients. Our unique dataset included around 50 studies, 10 new datasets, and 6,000 SS parameters worldwide, using either single (e.g., fish) or multiple trophic levels (e.g., from plankton to fish). We tested whether more negative slopes (i.e., greater relative contribution of small-sized individuals) were observed in ecological communities located in warm or low-latitude regions. The current work also identified several knowledge gaps in the SS research. Importantly, a consensus should be found on how to apply SS research, especially regarding the selection of size classes in binning methods, and model fitting for single or multiple trophic levels. In conclusion, our results emphasise the need for a comprehensive systematic review to provide a more realistic understanding of the complexity of SS in humanimpacted aquatic ecosystems.

A10.13 RESPONSES OF INDIVIDUAL SIZE DISTRIBUTIONS ACROSS A CONTINENTAL GRADIENT OF TEMPERATURE AND RESOURCE SUPPLY

Thursday 6 July 2023 17:45

Jeff Wesner (University of South Dakota, United States), Savina Gjoni (University of South Dakota, United States), Justin Pomeranz (Colorado Mesa University, United States), Jim Junker (Michigan Tech University, United States)

jeff.wesner@usd.edu

Over 50 years of research reveals a common pattern across ecosystems in which abundance (N) declines with increasing body mass (M). The shape of this relationship is described by a power law, N~ Mb , and the exponent varies in relation to changes in energy flow through the food web. The value of b is almost always negative, indicating a remarkably consistent ecological pattern. However, climate change is expected to alter size-spectra, based in part on shifts in body size with temperature that are predicted from macroecological temperaturesize rules. In addition, deviations from theoretical predictions of the b-temperature relationship may be resolved by accounting for variation in resource supply, but the effect of resource supply at large scales is also unknown. We examined the response of 145 size-spectra (fish and macroinvertebrates) collected from 24 freshwater streams in North America that varied by 25 degrees C and also varied in resource supply, measured as gross primary production and allochthonous subsidies. Despite strong environmental variation, complete species turnover, and changes in mean body size, preliminary results suggest no change in b across the temperature or GPP gradients. Across all samples, b averaged -1.4, shallower than theoretical predictions, but consistent with benthic marine systems. Our work suggests that individual size distributions are stable across North American streams.

A11 PLASTICITY AND RESILIENCE OF DEVELOPMENTAL STAGES TO CLIMATE CHANGE

ORGANISED BY: KATHARINA RUTHSATZ (TECHNICAL UNIVERSITY OF BRAUNSCHWEIG) , NICHOLAS WU (WESTERN SYDNEY UNIVERSITY), PATRICE POTTIER (UNSW SYDNEY)

A11.1 ACUTE THERMAL TOLERANCE IN FISH EMBRYOS: IS THIS THE MOST SENSITIVE LIFE STAGE?

Tuesday 4 July 2023 09:00

Zara-Louise Cowan (Norwegian University of Science and Technology, Norway), Anna H. Andreassen (Norwegian University of Science and Technology, Norway), Jeremy De Bonville (Université de Montréal, Canada), Leon Green (University of Gothenburg, Sweden), Sandra A. Binning (Université de Montréal, Canada), Lorena Silva-Garay (Norwegian University of Science and Technology, Norway), Fredrik Jutfelt (Norwegian University of Science and Technology University of Gothenburg, Norway), Josefin Sundin (Swedish University of Agricultural Sciences, Sweden) zaralouisecowan@gmail.com

Aquatic ectotherms are particularly vulnerable to thermal stress, with certain life stages (embryos) predicted to be more sensitive than others (juveniles and adults). When examining the vulnerability of species and life stages to warming, it is particularly important to use appropriate and comparable methodology so that robust conclusions can be obtained. Critical thermal methodology (CTM) is commonly used to characterise acute thermal tolerances in fishes, with critical thermal maximum (CTmax ) referring to a measured endpoint defining the upper acute thermal tolerance limit. This is the temperature at which fish exhibit loss of locomotory movements (i.e., loss of equilibrium) due to a temperature-induced collapse of vital physiological functions. While it is relatively easy to monitor behavioural responses and measure CTmax in juvenile and adult fish, this can be much more challenging in embryos. Here, we will present a novel method for measuring acute upper thermal tolerance limits in fish embryos, where CTmax is defined by the temperature at which embryos stop moving. Measurements of CTmax based on last movement are more conservative than measurements based on last heartbeat, additionally they are easier to record and work well with both large and small embryos. Importantly, measurements of CTmax based on last movement in embryos are similar to measurements from larval and adult stages based on loss of locomotory control. The last movement technique described here allows for comparisons of acute thermal tolerance of embryos between species, across life stages within species, and as a response variable to treatments.

A11.2 FEMALE FERTILITY IS MORE SENSITIVE TO HEAT WAVE CONDITIONS THAN MALE FERTILITY IN BLOOD FEEDING TSETSE FLIES (GLOSSINA PALLIDIPES)

Tuesday 4 July 2023 09:30

Hester Weaving (University of Bristol, United Kingdom), John S Terblanche (Stellenbosch University, South Africa), Sinead English (University of Bristol, United Kingdom) hester.weaving@bristol.ac.uk

Critical thermal limits, the upper and lower temperature at which an organism can survive, are widely used to infer climate change related vulnerability. However, there is evidence in many species that sterility occurs within a narrower temperature range. Beyond this, evidence has shown that thermal fertility limits also better match current species distributions, and therefore may be used to make more accurate predictions into the future. In our study, we determine the effect of heat wave conditions (two hours of 25, 36, 38 or 40°C, over three consecutive days) on reproductive output and mortality of tsetse (Glossina pallidipes), an obligate blood feeding fly and vector of trypanosomiasis in sub-Saharan Africa. By exposing either male or female tsetse to heat wave conditions, we reveal that female fertility is much more sensitive to high temperature than male fertility. For male tsetse, individuals die before they become sterile. This is in opposition to widely accepted thinking that male fertility is more sensitive to heat. At 40°C we find that survival of both males and females declines to almost zero. Additionally, we find evidence for transgenerational plasticity where offspring of heat exposed mothers have higher critical thermal maximums. These findings may mean that using critical thermal limits alone to estimate climate change vulnerability could underestimate risk, and that fertility limits and critical limits should be used in combination to provide more robust estimates.

A11.3

Tuesday 4 July 2023 09:30

DEVELOPMENTAL TEMPERATURE AFFECTS THE ONTOGENY OF THE CIRCADIAN RHYTHM IN GILTHEAD SEA BREAM (SPARUS AURATA)

KATERINA A. MOUTOU (UNIVERSITY OF THESSALY, Greece), Alexia Fytsili (University of Thessaly, Greece), Andreas Tsipourlianos (University of Thessaly, Greece), Rafael Angelakopoulos (University of Thessaly, Greece), Themistoklis Giannoulis (University of Thessaly, Greece), Zissis Mamuris (University of Thessaly, Greece)

kmoutou@uth.gr

Climate change is expected to impact all taxa of living organisms by driving developmental and physiological adaptations of organisms towards new trajectories. This is particularly important for poikilothermic organisms, such as the teleosts, that cannot regulate their body temperature, with unexpected consequences for the ecosystems, fisheries and aquaculture. Under these circumstances, circadian rhythm, the internal “clock” that regulates all biological processes, is crucial in surviving and driving plasticity under changing conditions. In this study we examined the effect of different early rearing temperatures on the genes implicated in the regulation and function of the circadian clock in gilthead seabream (Sparus aurata) larvae, considering the outcome of the teleost-specific whole genome duplication. Larvae were exposed in three different temperatures, 17, 20 and 23°C, from epiboly to the end of yolksac larval stage, and from the exogenous feeding stage onwards, they were kept at 20°C. RNA sequencing was carried out in larvae sampled at first feeding, notochord flexion and mid metamorphosis stages, followed by real-time RT-PCR validation. All developmental stages were affected by an acute temperature increase, which underregulated gene expression. Remarkably, first feeding proved the most vulnerable stage to this acute thermal stimulus. As the larvae developed and became temporally distant from the thermal stimulus, differences in gene expression became non-significant. Overall, genes with a core function remained unaffected, whereas genes with a regulatory role seem to be more susceptible to the environmental stimuli, possibly by acting to synchronise the molecular machinery with the environmental changes.

A11.4 METABOLIC COSTS OF CALCIFICATION – IS SKELETOGENESIS REALLY A METABOLIC CHALLENGE FOR MARINE LARVAE?

Tuesday 4 July 2023 09:30

Meike Stumpp (Christian-Albrechts-University Kiel, Germany)

mstumpp@zoologie.uni-kiel.de

The production of a skeleton composed of a specific CaCO3 polymorph requires an environment that underlies tight biological control. The controlled transport of calcium ions, the concentration of inorganic carbon and regulation of cellular acid-base equilibria is likely associated with energetic demands that remain little investigated. To measure energetic costs for calcificication, we analyzed metabolic markers on several levels of biological organization using the sea urchin larva as model that develops an elaborate calcitic endoskeleton. Calcification is stimulated by dissolving the existing skeleton by low pH and subsequent recalcification under control pH conditions. During this recalcification phase we measured citrate synthase (CS) expression, CS activity, mitochondrial density in the calcifying cells and whole animal routine metabolic rates. These measurements were performed under control (pH 8.1) and acidified seawater (pH 7.5 and 7.0) conditions to determine the energetic requirements to calcify under environmental challenge. The results demonstrated that energetic requirements for calcification under control conditions are

negligible compared to overall metabolic costs for living and reduced seawater pH induced a mild increase in metabolic rates associated with increases in mitochondrial density in calcifying cells as well as CS expression and enzyme activity. These findings highlight, that calcification under present-day oceanic conditions is a highly energy efficient process, that however can be challenged by a decrease in seawater pH expected for the end of the century. Thus, the energetic efficiency of an evolutionary ancient process may contribute to the sensitivities or robustness of marine calcifiers in changing past and future oceans.

A11.5 PREDICTING DEVELOPMENTAL RESPONSES TO FLUCTUATING TEMPERATURES IN LYMNAEA STAGNALIS

Tuesday 4 July 2023 09:30

Ziad Ibbini (University of Plymouth, United Kingdom), Manuela Truebano (University of Plymouth, United Kingdom), John Bishop (Marine Biological Association, United Kingdom), Oliver Tills (University of Plymouth, United Kingdom) ziad.ibbini@students.plymouth.ac.uk

Efforts to predict physiological responses to natural thermal environments, and to future climate change scenarios, often make use of thermal performance curves (TPCs). However, a number of recent studies have highlighted discrepancies between predictions made via modelling with TPCs and those observed in empirical data. We imaged Lymnaea stagnalis embryos throughout their development in response to constant temperatures (CTs) (15.0 to 32.5°C, at increments of 2.5°C), and to semi-natural fluctuating temperatures (FT) (‘cold’: 17.4 ± 8°C, ‘warm’: 24 ± 8°C). Thus, we could test whether TPCs quantified for constant temperatures could accurately model responses to FTs, and subsequently test whether hourly physiological rates (growth and movement) could identify factors driving discrepancies in these predictions. We identified several key results from these experiments: 1) modelling using TPCs quantified from CTs could accurately predict mean developmental and growth endpoints in the 'cold' FT treatment, but not for the 'warm' FT treatment, 2) hourly growth in the FT treatments could be more accurately predicted by dynamically adjusting predictions using growth curves from the CT treatments, 3) delayed responses in hourly rates of growth and movement to daily extreme temperatures were observed in both FT treatments. Our results highlight the importance of collecting empirical data with finer temporal resolution to enable more thorough evaluation of methods for predicting physiological responses to variable thermal conditions.

A11.6 INTEGRATING PHENOTYPIC PLASTICTY INTO CONSERVATION HATCHERIES PRACTICES

Tuesday 4 July 2023 09:30

Florian Mauduit (University of California Davis, United States), Dennis E. Cocherell (University of California Davis, United States), Heather N. Bell (University of California Davis, United States), Richard E. Connon (Unviersity of California Davis, United States), Nann A. Fangue (University of California Davis, United States)

fmauduit@ucdavis.edu

Starting in 2022, Delta smelt (Hypomesus transpacificus) spawned and reared at the UC Davis Fish Conservation and Culture Laboratory (FCCL) have been released into the San Francisco Bay Delta as a last resort to prevent the extinction of the wild population. One major concern is that refuge populations adapt to captivity and may not be fit for the challenges posed by a wild environment. For instance, the current FCCL husbandry conditions include a stable temperature of 16°C throughout the life of the organisms, which may result in fish performing at a high level, but across a narrow range of temperatures with reduced temperature tolerance. In that context, we assessed the possibility of increasing Delta Smelt upper thermal tolerance and thermal performance breadth by exposing embryos from fertilization to hatch to three temperature regimes: stable 16°C, fluctuating 16-20°C and stable 20°C. At hatch, we measured the hatching success, yolk sac volume and upper thermal tolerance of larvae from the three treatments using a cardiac assay. Our first results indicate that larvae exposed to 16-20°C have a higher upper thermal tolerance than organisms exposed to stable 16°C. Moreover, and unlike in the group exposed to 20°C, no detrimental effect such as reduced hatching success and mortality was observed. To verify if temperature experienced during ontogeny influenced organisms' upper thermal tolerance throughout their life, upper thermal tolerance will be reevaluated after a period of common garden. This study could inform future husbandry practices and improve the supplementation program’s chance of success.

TO UNDERSTANDING ENVIRONMENTAL SENSITIVITY

Tuesday 4 July 2023 09:45

Jamie C.S. McCoy (University of Plymouth, United Kingdom), John I. Spicer (University of Plymouth, United Kingdom), Simon D. Rundle (University of Plymouth, United Kingdom), Oliver Tills (University of Plymouth, United Kingdom)

james.mccoy@postgrad.plymouth.ac.uk

During early development, animals are typically more sensitive to environmental change. Developmental responses to elevated temperatures are hugely multifaceted and encompass changes to form, function and performance at timescales ranging from minutes to days. Manually measuring such responses is therefore inherently limited. ‘Energy proxy traits’ (EPTs) are a new approach, involving the measurement of energy across different temporal frequencies in the fluctuations of mean pixel values from video of developing animals. EPTs can characterise acute and chronic responses to environmental stress, but they remain untested in comparing the sensitivity of different species, a significant precursor to establishing their utility as a scalable and comparative approach to measuring biological responses. Using EPTs I tested the thermal sensitivity of embryos of three freshwater gastropod species with distinct differences in their embryonic development, specifically, in the timings of a number of key physiological and behavioural developmental events. EPT spectra were significantly different between species, temperatures and development stages, with differences corresponding with the onset of multiple developmental events. Furthermore, differences in the relative timings of developmental events between species, individuals and temperatures were reflected in EPT spectra through

development. Universality of measurements that extend between species and stages of development will further our understanding of developmental phenotypic responses to environmental change, but also push the boundaries of how we measure responses of animals during their most dynamic early life stages.

A11.8 SENSITIVITY OF EARLY LIFE STAGES OF FISHES TO ANTHROPOGENIC STRESSORS AND RELEVANCE FOR POPULATION DYNAMICS

Tuesday 4 July 2023 10:00

Marta Moyano (Norwegian Institute for Water Research, Norway)

marta.moyano@niva.no

Gaining a mechanistic understanding of the impact of climate and anthropogenic stressors on wild fish populations is essential for making robust predictions under future scenarios. In the past decade, there has been an increased interest into evaluating how various stressors may impact different life stages and how the carry-over effects may influence the fate of the individuals and populations. This intense research has been accompanied by the development and/or adaptation of experimental methods for early life stages to be comparable to those for larger fish. Using Atlantic herring (Clupea harengus) and European seabass (Dicentrarchus labrax) as case studies, I will present an overview of the differential impacts of ocean warming, acidification, and changes in prey (and their interactions) across life stages, as well as the methodological challenges encountered (e.g. transgenerational experiments in long-lived species). Within this multistressor context, I will discuss the relevance and complexity of conducting community experiments to explore cumulative impacts. Finally, I will present how we have used our empirical results to generate physiological indicators and/or to parameterize models to predict fish growth and survival (and thus population productivity) for these species in a changing sea.

A11.9 EMBRYONIC HEAT TOLERANCE AND THE VULNERABILITIES TO CLIMATE CHANGE IN LIZARDS

Tuesday 4 July 2023 13:30

Baojun Sun (Key Laboratory of Animal Ecology and Conservation Biology Institute of Zoology Chinese Academy of, China), Weiguo Du (Key Laboratory of Animal Ecology and Conservation Biology Institute of Zoology Chinese Academy of, China)

sunbaojun@ioz.ac.cn

Climate warming has imposed numerous negative effects on animals. As the most vulnerable life stage, the embryonic heat tolerance of oviparous ectotherms to climate warming determines the individual survival and population dynamic. Therefore, embryonic heat tolerance is a growing concern in global change biology. With embryos from several species/populations of Takydromus lizards in mainland China, we conducted factorial manipulations at ecological, physiological, biochemical, and molecular hierarchies, aiming to reveal the latitudinal pattern of embryonic heat tolerance and predict the vulnerabilities of

A11.7 MEASURING THE MOST SENSITIVE STAGES OF LIFE AS A SPECTRA OF ENERGY – AN APPROACH

oviparous ectotherm to climate warming. We found that embryonic chronic heat tolerance (i.e., resistance to warming average temperature, ECHT) and acute heat tolerance (i.e., resistance to heat events, EAHT) collectively determined embryonic survival, but frequent extreme heat events rather than a gradually increasing average temperature are the main threats to embryos under climate warming. Moreover, the embryos of Takydromus lizards from mid and high latitudes own higher EAHT than species/populations from low latitudes. In addition, the embryonic responses at physiological, biochemical, and molecular levels indicated that the EAHT was significantly affected by oxygen concentration, which supported the hypothesis of ‘oxygen and capacity limited thermal tolerance’ (OCLTT). By integrating embryonic heat tolerance and climatic data, we predicted that ectotherms at low latitudes would be more vulnerable to climate warming due to limited embryonic heat tolerance. We also suggest an importance of integrating physiological, biochemical, and molecular levels in exploring the effects of climate warming on animals.

A11.10 RAPID HEAT HARDENING IN EMBRYOS OF THE LIZARD ANOLIS SAGREI

Tuesday 4 July 2023 14:00

Alex R Gunderson (Tulane University, United States), Grace Gleason (Tulane University, United States), Katherine Starr (Loyola University, United States), Thomas J Sanger (Loyola University, United States)

agunderson@tulane.edu

Understanding how heat tolerance plasticity evolves is crucial in a warming world. It has been hypothesized that selection will favor high levels of tolerance plasticity in immobile embryonic stages (e.g., eggs) because they have very limited capacity to behaviorally thermoregulate. That said, our knowledge of embryonic heat tolerance plasticity lags far behind what is known for later life stages. We tested for heat tolerance plasticity in embryos of the brown anole lizard (Anolis sagrei), focusing on rapid heat hardening. We compared survival of an episodic extreme heat event between embryos that either did (Hardened) or did not (Non-hardened) receive a high but non-lethal heat pre-treatment two hours prior. We also measured heart rates before and after heat exposure to test for metabolic consequences of thermal treatments. We found that Hardened embryos were significantly more likely to survive extreme heat than Non-hardened embryos. However, the induction of the hardening response also appears to come with a metabolic cost: temperature-standardized measurements show that heart rates of Hardened embryos increased after the heat pre-treatment, while the heart rates of Non-hardened embryos did not change over the same time period. To our knowledge, this is the first demonstration of rapid heat hardening in a Squamate embryo. Greater consideration of embryonic thermal plasticity is required to understand general patterns of plasticity evolution across life stages and to help deepen our understanding of the consequences of global change.

A11.11 INVESTIGATING THE NATURE AND PROXIMATE CAUSES OF GENETIC VARIATION IN PLASTICITY TO COMBINED ENVIRONMENTAL STRESSORS

Tuesday 4 July 2023 14:15

Avishikta Chakraborty (University college london, United Kingdom), Christen Kerry Mirth (Monash University, Australia), Carla Marie Sgro (Monash University, Australia)

avishikta0403@gmail.com

Climate change has compelled organisms to face variable environmental conditions. In addition to the direct impacts of temperature on animals,changes in the thermal environment will also affect the distribution and quality of nutritional resources available to an animal. Thus,animals must cope with simultaneous changes in their diet and temperature. A way through which organisms can survive such conditions in the short term would be via phenotypic plasticity. The extent of this plastic response depends on their genetic makeup, with some genotypes exhibiting greater plasticity towards certain environmental conditions than others. Using Drosophila melanogaster, we explored genetic variation in the response of multiple lifehistory traits to combinations of rearing diet and temperature, both across and within populations. We found population-specific variation in plastic responses among traits, however there was no evidence of plasticity gradients that correlated with latitude. This highlights the need to consider multiple environmental factors, different populations, as well as different traits, to better to predict an animal’s plastic response to environmental change. Within a population we found distinct underlying patterns of plasticity in response to combinations of thermal and nutritional stress, that could not have been predicted from the overall population mean response. This emphasises the importance of cryptic, withinpopulation variation in plasticity, which is likely to facilitate adaptation to changing environments. Through this talk I aim to accentuate the multifaceted nature of plasticity which will aid in research aiming to more accurately predict an animal’s vulnerability and persistence in the face of ongoing environmental change.

A11.12 THE IMPACT OF SHORT-TERM HEAT EXPOSURES ON FEMALE FITNESS IN A MODEL INSECT

Tuesday 4 July 2023 14:30

Ramakrishnan Vasudeva (University of Leeds, United Kingdom), Benjamin Cole (University of East Anglia, United Kingdom), Alexei A Maklakov (University of East Anglia, United Kingdom)

r.vasudeva@leeds.ac.uk

Extreme heat events under a warming planet will make ectothermic reproduction more prone to failures before species-specific critical thresholds are achieved. While plasticity can provide some flexibility, male and female insects can achieve optimal reproductive success differently under varying conditions. Previous work using the flour beetle Tribolium castaneumshowed that mature males experiencing thermal stress from heatwaves had their fertility halved. But the effect on mature females or ova remains unknown. We test this using

ecologically relevant, short-term (2hr) thermal stress mimicking the hottest part of the day during a heat event. Using two experimental approaches where, a)ova collected in batches from >150 freely ovipositing females at 30° C exposed to 48° C or 50° C for 2hrs or b) freely interacting, reproducing mature adult females exposed to 48° C or 50° C for 2hrs. After exposures, the fodder containing the ova were incubated at 30° C from both experiments, isolating all adults from ovipositing, (b). Fitness was scored as offspring viability after incubation at 30° C. A control was maintained at 30° C for comparison. We found that, at 48° C (2hrs), fitness of reproducing females plummeted by 99% and survival of ova declined by 69% compared to controls. Ova was more resilient than the reproductive adult stage. However, with just a 2° C increase in heat stress to 50° C, performances of both stages remained low and comparable, a mere 0.7% of the ova survived to adulthood compared to 0% of the adults. Combined, these results highlight the contrasting impacts of thermal stress on ectotherms under climate warming.

PLASTICITY, DIVERSIFIED BET-HEDGING, AND ROBUSTNESS: WHAT DOES IT MEAN TO BE UNSTABLE??

Tuesday 4 July 2023 14:45

Sanjana Venkatesh (McMaster University, Canada), Alexander Little (McMaster University, Canada)

sanjanavenkatesh99@gmail.com

Plasticity and diversified bet-hedging (DBH) are strategies that arguably invoke instability by design to promote phenotypic flexibility in early development. Canalization and robustness, on the other hand, represent buffering against early environmental inputs and developmental noise to promote genetically fixed traits. While often thought to stem from mutually distinct underlying processes, we propose that these strategies may be more mechanistically linked than previously considered. We use clonal lines of starlet anemones, Nematostella vectensis, to empirically test whether inter- and intra-genotype variability in early development reflects interactions between plasticity, DBH, and robustness. Within a given genotype, there may be variation in the trait means that are expressed as a result of phenotypic plasticity. In addition to this, there may also be differences in the repeatability of this expression, that would indicate the level of robustness associated with its plastic response. Isogenic lines of Nematostella are an ideal system to test these ideas because the development of individual genotypes can be repeated many times both within and across developmental treatments. We predict that the robustness of the plastic response of a genotype would vary within the clones, thereby allowing us to categorize the individuals as differentially plastic. Differences in robustness and canalization can provide comparative developmental contexts not possible in most animal models. Understanding robustness and canalization of plastic and DBH strategies is crucial to interpret how population mean trait values respond to environmental perturbations and test whether plasticity carries intrinsic costs.

Tuesday 4 July 2023 15:30

Shaun Killen (University of Glasgow, United Kingdom), Ricardo Beldade (Pontificia Universidad Católica de Chile, Chile), Amelie Crespel (University of Turku, Finland), Giacomo Bernardi (University of California Santa Cruz, United States), Isabelle M Côté (Simon Fraser University, Canada), Suzanne C Mills (CRIOBE, France)

shaun.killen@glasgow.ac.uk

There is urgent need to understand the factors that may allow some species to adapt to ongoing climate change. The pristine status of the Iles Éparses in the Indian Ocean, and historic exposure to differing temperatures along a latitudinal gradient, are ideal for studying the effects of thermal history and species life-history on thermal plasticity. We collected juveniles and adults of two site-attached coral reef species that show different levels of genetic connectivity from two different islands across a 5° difference in latitude in the Iles Éparses: skunk anemonefish Amphiprion akallopisos and domino damsel Dascyllus trimaculatus. After temperature elevation, D. trimaculatus showed an increased aerobic scope at both latitudes during the adult and juvenile stages. However, A. akallopisos – a species with less gene flow between populations – showed evidence of a reduced capacity for plasticity, especially during the juvenile stage. These results suggest higher trait plasticity for species and populations with higher levels of gene flow. Furthermore, aerobic scope was lowest in fish from the warmer Juan de Nova, suggesting that both fish species, even the more phenotypically plastic D. trimaculatus, were approaching their thermal limit. Data from endocrine analysis support these results and also suggest sex-specific differences. These results aid in predicting which coral reef fish species are more likely to acclimate to future temperatures and improve our understanding of the evolution and maintenance of biodiversity in our changing world.

A11.15 HOW DO RESPONSES TO PARENTAL AND OFFSPRING ENVIRONMENT INTERACT TO MEDIATE OFFSPRING PERFORMANCE?

Tuesday 4 July 2023 15:30

Amanda Pettersen (The University of Sydney, Australia), Frank Seebacher (The University of Sydney, Australia), Neil Metcalfe (University of Glasgow, United Kingdom)

amanda.pettersen@sydney.edu.au

The world is undergoing rapid environmental change, and organisms are facing development of a critical life stage under increasingly warmer conditions. Development from a single fertilised cell to a feeding organism is common to all organisms and constitutes a metabolically expensive period of early life that is vulnerable to environmental stress. For animals that develop in eggs (e.g., reptiles, fish, insects), extreme temperatures, such as those predicted under global warming, will increase metabolic rates, thereby reducing energy reserves at hatching that would otherwise be available to enhance survival, growth, and reproduction. Phenotypic plasticity, both within and across generations, represents a mechanism by which organisms can rapidly respond to environmental stress. Parental environment can shape per offspring investment as well as the response of offspring to their environment, while offspring may also have the capacity to regulate responses to the local environment. For example, mothers exposed to high

A11.13

A11.14 METABOLIC PLASTICITY TO ELEVATED TEMPERATURE AS A FUNCTION OF THERMAL HISTORY, GENE FLOW AND LIFE-STAGE IN CORAL REEF FISHES

temperatures may increase per offspring investment and produce offspring with downregulated metabolic rates to enhance survival under energetically costly developmental environments. The extent to which among and/or within generation plasticity may buffer offspring from costly development under warming temperatures is unclear. Here we manipulate the parental and offspring environment in zebrafish to test the potential role of among and within generation plasticity, and its context-dependent implications for offspring phenotype and fitness.

A11.16 EXPOSURE TO MULTIPLE STRESSORS DURING EMBRYOGENESIS CAUSES TEMPORALLY UNSTABLE EFFECTS IN ZEBRAFISH (DANIO RERIO)

Tuesday 4 July 2023 16:00

Daniel M Ripley (The University of Manchester, United Kingdom), Joanna Smithson (The University of Manchester, United Kingdom), Jade Brown (The University of Manchester, United Kingdom), Charlotte Marris (The University of Manchester, United Kingdom), Adam Stevens (The University of Manchester, United Kingdom), Holly A Shiels (The University of Manchester, United Kingdom)

daniel.m.ripley@gmail.com

The warming of rivers and lakes increases their likelihood of experiencing hypoxic events, rendering the study of these co-occurring stressors of great importance. Due to their developing cardiovascular systems, embryonic fishes are particularly vulnerable to warming and hypoxia. Exposure to single environmental stressors (e.g. warming or hypoxia) during embryogenesis can cause phenotypic changes that ‘persist’ into adulthood through the mechanism of developmental programming. However, few studies have explored the potential interactions between multiple stressors and how their effects may change throughout a lifetime. Here, we expose zebrafish to warming (+ 5 ºC), hypoxia (50% air saturation), and their combination (+ 5 ºC and 50% air saturation) throughout embryogenesis before moving them to common conditions (28 ºC and 100% air saturation) and investigating their physiology at both three- and six-months old. Developmental conditions had long-term, but temporally changing effects on the growth, aerobic scope, and environmental tolerances of zebrafish, with the combination of warming and hypoxia inducing effects not caused by either stressor alone. These novel physiological effects induced by combined warming and hypoxia were mirrored in the cardiac transcriptome, with each treatment group displaying a distinct set of differentially expressed genes. Finally, three-way interactions between developmental temperature, oxygen saturation, and age, affected several physiological parameters, clearly demonstrating the importance of integrating multiple environmental stressors, time points, and physiology metrics when studying the effects of climateinduced developmental programming in fishes.

tblanchard@zoology.ubc.ca

Temperatures in aquatic environments often vary diurnally; however, most studies to date have focused solely on the effects of constant temperature during early development in fishes. Temperature variability is predicted to increase in frequency with ongoing climate change and is projected to have an even greater impact than the increase in average mean temperatures. Therefore, our objective was to investigate if fluctuating environments during embryonic development have persistent phenotypic effects in juveniles in fishes. To address this objective, we used a small topminnow, Fundulus heteroclitus, which inhabits intertidal salt marshes along the Atlantic coast of North America - an environment that exhibits substantial daily thermal variation. We exposed embryos to four different thermal regimes with the same mean temperature: 26±0°C, 26±3°C, 26±5°C, and 26±7°C on a diurnal cycle. The two largest fluctuation regimes exposed embryos to temperatures slightly above their developmental thermal optimum. Once hatched, fish were raised at a constant common temperature of 26°C to test for the persistent effects of developmental plasticity. We found that embryos exposed to fluctuations of ±3°C during embryonic development had improved thermal tolerance (measured as agitation temperature). On the contrary, larvae from the largest fluctuating regime ( ±7°C), exhibited both a decrease in hypoxia tolerance and thermal tolerance (CTMax). Temperature fluctuation also had persistent effects on the expression of genes involved in both thermal and hypoxia tolerance. Overall, our data suggest that while small fluctuations may be beneficial, larger thermal fluctuations during early development may have negative effects on juvenile phenotypes

Tuesday 4 July 2023 16:15

Tuesday 4 July 2023 16:30

Warren Burggren (University of North Texas, United States)

burggren@unt.edu

Animal experiencing enhanced stressors during climate change have few options available to enhance their long-term survival. One deeply understood mechanism involves natural selection, leading to evolution of new adaptations that help cope with what can be extreme and stochastic weather events associated with climate change. Potentially highly effective at staving off environmental challenges, adaptations are typically very slow and incremental in appearing. Moreover, adaptations, of course, involve very large numbers of generations over considerable time. An alternative mechanism that could help adults and their developing offspring survive effects of climate change involves an ability to rapidly create alternate phenotypes based on developmental phenotypic plasticity. Developmental plasticity springs from inherent adaptations for plasticity that enable such rapid, within-generation changes. However, it is increasingly

Tessa S Blanchard (University of British Columbia, Canada), Madison L. Earhart (University of British Columbia, Canada), Rashpal Dhillon (University of British Columbia, Canada), Ravinder Sheena (University of British Columbia, Canada), Leah R.E. Campbell (University of British Columbia, Canada), Patricia M. Schulte (University of British Columbia, Canada)v

A11.18 ‘HEDGING’ AGAINST CLIMATE CHANGE IN DEVELOPING ANIMALS: ADAPTATION (SLOW BUT LASTING) VS. EPIGENETICALLY-DERIVED PLASTICITY (FAST BUT TRANSIENT)

A11.17 TEMPERATURE FLUCTUATIONS ALTER JUVENILE PHENOTYPES THROUGH DEVELOPMENTAL PLASTICITY IN FUNDULUS HETEROCLITUS

appreciated that epigenetic influences during development can lead to very rapid phenotypic changes that can also be very widespread throughout a population, rather than confined to a few individuals with gene mutations (favorable or unfavorable). Such epigeneticallyinduced phenotypic plasticity can arise rapidly and just as rapidly be sunsetted within a generation or across a few generations, providing some capability to withstand environmental stressors emerging from climate change. Important to emphasize is that the survival mechanisms resulting from adaptations and developmental phenotypic plasticity are not necessarily mutually exclusive, allowing for ‘bet hedging’ to enhance survival during weather events emerging from climate change, . Emerging evidence indicates that epigenetically-induced phenotypic changes can actually become fixed in the genome, representing the ‘best of both worlds’ as climate changes.

POSTER SESSIONS

Wednesday 5 July 2023

17:15-19:15

A11.19 MECHANISMS IN CHINOOK FRY AND PARR

Wednesday 5 July 2023 POSTER SESSION

Kim Birnie-Gauvin (Technical University of Denmark, Denmark), Natalie Butler (University of British Columbia, Canada), Scott G Hinch (University of British Columbia, Canada), Erika J Eliason (University of California Santa Barbara, United States)

kbir@aqua.dtu.dk

Determining thermal limits is now considered a global priority given the unprecedented rate at which global climate change is altering the planet. In fishes, the Critical Thermal Maximum (CTmax) approach has more or less dominated the field when it comes to assessing thermal limits, largely due to its ease, rapidity and low cost. However, the ecological relevance of CTmax has been criticised because it uses loss of equilibrium - an incipient lethal threshold - as an endpoint. More recently, CTswim - the temperature at which of fish fatigues following acute warming - has emerged as a likely candidate for a more ecologically relevant measure of thermal limits. Here, we 1) compare thermal limits derived from CTmax and CTswim, in two life stages of Chinook salmon (fry and parr), and 2) assess tissue-level metrics (lactate, lactate dehydrogenase and citrate synthase) at CTswim in an attempt to reveal the mechanisms that determine why fish quit swimming at warm temperatures, and to more broadly gain insight on the mechanisms that define tolerance to acute warming.

A11.20 LONG-LASTING AND INTERGENERATIONAL EFFECTS OF DEVELOPMENTAL TORPOR USE ON SEASONAL HETEROTHERMY AND TELOMERE DYNAMICS

Wednesday 5 July 2023

POSTER SESSION

Lilian Redon (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Bernadette Carré (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Hanna Rauch-Schmücking (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Friederike Pohlin (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Caroline Habold (DEPE IPHC CNRS Strasbourg, France), Steve Smith (Konrad Lorenz Institute of Ethology University of Veterinary Medicine

Vienna, Austria), Caroline Gilbert (CNRS National Veterinary School of Alfort MECADEV laboratory Maison-Alfort, France), Sylvain Giroud (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria)

Lilian.Redon@vetmeduni.ac.at

In small endotherms, hypometabolic responses such as torpor represent an efficient energy-saving strategy enabling individuals to deal with unfavourable environmental conditions. Early-life experience is known to influence individual life-history traits, including shaping the metabolic phenotype, with possible effect on individual somatic maintenance,e.g., the erosion of telomeres, the protective end-cap of chromosomes. This study investigated (i) the life-long effect of developmental use of torpor on heterothermic patterns and telomere length dynamics, and (ii) the possible carry-over effect of these modifications to the next generation in a seasonal heterotherm, the Garden dormouse (Eliomys quercinus). To do so, we measured torpor patterns, and determined telomere length, via qPCR, in individuals displaying a high torpor (‘HT’) or a low torpor (‘LT’) frequency during development, as well as in their respective offspring. During adulthood, HT individuals displayed higher torpor frequency and duration, and greater telomere attrition over their lifetime compared to LT dormice. Similar differences in torpor phenotype seem to occur in the offspring from HT or LT parents. First results on telomere dynamics reveal no apparent parental effect of developmental torpor use on offspring telomere lengths, which however appear to be shorter than those of parents and constant during the first year of life. In line with the literature, these results show that increased torpor use during earlylife (i) induce a higher heterothermic expression over the individual lifetime and (ii) is associated with somatic costs including faster telomere erosion and possibly decreased lifespan, with significant consequences for the next generation.

A11.21 CONSEQUENCES OF DIRECTLYAND INDIRECTLY-EXPERIENCED HEAT STRESS IN A MUTAGENIC ENVIRONMENT

Wednesday 5 July 2023

Katharina Wollenberg Valero (University College Dublin, Ireland), Lauric Feugere (Universite du Quebec a Rimouski, Canada), Claudio Silva de Freitas (University of Hull, United Kingdom), Adam Bates (Wellcome Sanger Institute, United Kingdom), Kenneth Storey (Carleton University, Canada), Pedro Beltran-Alvarez (University of Hull, United Kingdom)

katharina.wollenbergvalero@ucd.ie

Climate change increases both the frequency and duration of heat events. In aquatic animals, direct negative effects of such heat stress may be exacerbated indirectly through heat-induced stress communication via secreted metabolites. Little is known about the fate and performance of fish embryos which have experienced direct

or indirect heat stress in a mutagenic environment. In this study, we first exposed zebrafish embryos to three treatments consisting of direct heat stress, stress metabolites from heat-stressed conspecifics, and combined heat + heat-induced stress metabolites, before subsequently undergoing a UVB/UVA damage/repair assay to mimic a mutagenic environment. Indirect heat stress led to longer embryos displaying over-developed pericardial widths and behavioural hypoactivity. Heat stress stimulated the cellular stress response, which protected and/or rescued embryos from subsequent UV damage and improved fitnessrelevant behaviours. However, heat stress combined with metabolites emitted by heat-stressed conspecifics overwhelmed embryos, which introduced RNA mutations, and lowered overall fitness indicators. Genes responding to UV were also more central to the zebrafish interactome, and connected with more other genes, than those responding to heat stress, but these genes were not activated when heat stress occurred under UV radiation. Whilst generated in the laboratory, these findings provide an important baseline for understanding the consequences of thermal stress history in naturally mutagenic environments, where direct and indirect heat stress co-occur.

A11.22 EPIGENETIC ADAPTABILITY IN EARLY LIFE STAGES OF MARINE FISH UNDER ACIDIFIED SEAWATER

Wednesday 5 July 2023 POSTER SESSION

Tzu-Yen Liu (Institute of Oceanography NTU, Taiwan), Yi-Ling Chou (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Ying-Jay Guh (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Yung-Che Tseng (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

rw6526@gmail.com

Ocean acidification (OA) has been recently recognized as a global environmental perturbation, potentially affecting ecosystems’ biodiversity, concordance, and functions. Several reports suggested that OA might cause functional damage in fish larvae regarding the recruitment of the population. To examine multigenerational OA effects, this study applied marine medaka (Oryzias melastigma) to CO2 -induced acidified conditions for three generations. The developmental characters and metabolic strategies were found to be changed in F1 and F2 generations. Acid-base regulation gene expressions of the F1 generation were up-regulated but recovered as the regular features in the F2 generation; however, larva's proton excretion capacity was raised in those acidified generations. The RNA-seq profiling conducted in each generation revealed significant differences between the F0 and F1 groups compared to the control, according to the gene ontogeny (GO) term analysis results. However, the F2 group was similar to the control group. Additionally, the analysis indicated changes in DNA methyltransferase activity in the CO2 exposition groups. We further checked the promoter’s DNA methylation levels of acid-base regulation genes and showed generational differences. Taken together, we may infer that marine fish could adapt to acidified environments over multiple generations by means of epigenetic modifications. Gaining insight into the epigenetic plasticity of marine fish under environmental stress would offer a more comprehensive understanding of the consequences of climate change on marine ecosystems.

A11.23 HOW DOES FOOD AVAILABILITY AFFECT INDIVIDUAL DIFFERENCES IN BEHAVIOUR, ACROSS DEVELOPMENT?

Wednesday 5 July 2023 POSTER SESSION

Josie McPherson (Josie McPherson, United Kingdom), Patrick Walsh (University of Edinburgh, United Kingdom), Eva Ringler (University of Bern, Switzerland), Julien Martin (University of Ottawa, Canada)

josie.mcpherson@ed.ac.uk

Consistent individual differences in animal behaviour are increasingly found to have important implications for ecology and evolution, perhaps particularly when adapting to new conditions from climate change or otherwise. However, how consistent individual differences in behaviour arise and change across ontogeny is understudied, especially in animals that develop via metamorphosis. In this project, I will investigate how the predictability, repeatability, plasticity and mean value of behaviours change across ontogeny and different nutritional environment in amphibians. Changes to organisms’ nutritional environments are becoming increasingly likely and frequent with climate change. To do this, I will raiseXenopus tropicalisin individual tanks split evenly into two groups, one of which will be fed on a high quality diet, and one on a low quality diet. After metamorphosis, the two groups will both be split into two, with half being fed a low quality diet and half a high quality diet. Incorporating this factorial experimental design will allow me to look at whether the diet preand post- metamorphosis interact synergistically, antagonistically or additively to affect behavioural development. Behavioural assays will be performed at three time points through development, once at the larval stage, post-metamorphosis and later life, to investigate whether individuality transcends metamorphosis. In all, I will be able to investigate both the impact of nutritional environment throughout development on consistent individual differences in behaviour.

A11.24 THE EFFECT OF EARLY TEMPERATURE EXPOSURE ON MITOCHONDRIAL BIOENERGETICS AFTER WHOLE GENOME DUPLICATION

Wednesday 5 July 2023 POSTER SESSION

Katerina A. Moutou (University of Thessaly, Greece), Artemis Kotoula (University of Thessaly, Greece), Andreas Tsipourlianos (University of Thessaly, Greece), Rafael Angelakopoulos (University of Thessaly, Greece), Alexia Fytsili (University of Thessaly, Greece), Zissis Mamuris (University of Thessaly, Greece)

kmoutou@uth.gr

A deviation from standard temperatures is an immediate climate change consequence that can affect organisms, especially poikilothermic, such as the teleosts. A number of biological processes that play a critical role in fish development and growth can be affected by those changes, including the oxidative phosphorylation (OXPHOS), which is responsible for almost 90% of the cell’s energy production. In this study we examined the consequences of different early rearing temperatures in cellular energetics of gilthead seabream (Sparus aurata) larvae, considering the outcome of the teleost-specific whole genome

duplication. Larvae were exposed in three different temperatures, 17, 20 and 23°C, from epiboly to the end of yolk-sac larval stage, and from the exogenous feeding stage onwards, they were kept at 20°C. The genes coding for OXPHOS complex IV including their paralogs were identified and examined. RNA sequencing was carried out in larvae sampled at first feeding, notochord flexion and mid metamorphosis stages. Differences were observed in gene expression levels among different stages and temperatures. Paralogous genes exhibited different ontogenetic patterns and responded differently to early temperature exposure. Whole genome sequencing data from samples with a different genetic background were combined with the RNA sequencing data to reveal a differentiated pattern of polymorphism between the paralogous genes. Besides amounting indications for sub-functionalisation of paralogous genes, the present study discusses how genome architecture may affect the impact of climate change on biological processes.

A11.26 THE BENEFICIAL EFFECTS OF AIR EXPOSURE FOR INTERTIDALLY SPAWNING FISH

Wednesday 5 July 2023

POSTER SESSION

Andrea Y. Frommel (University of British Columbia, Canada), Vandana Gokul Das (University of British Columbia, Canada), Sadie L.R. Lye (University of British Columbia, Canada), Colin J Brauner (University of British Columbia, Canada), Brian P.V. Hunt (University of British Columbia, Canada)

andrea.frommel@ubc.ca

Wednesday 5 July 2023 POSTER SESSION

Nicholas J. Bernier (University of Guelph Department of Integrative Biology, Canada), Michael Y.-T. Lim (University of Guelph Department of Integrative Biology, Canada)

nbernier@uoguelph.ca

Predicted climate change-induced increases in heat waves and hypoxic events will have profound effects on fishes, yet the capacity of parents to alter offspring phenotype via non-genetic inheritance and buffer against these stressors is not known. This study tested how prolonged adult zebrafish exposure to combined diel cycles of thermal stress and hypoxia affect offspring early survival and development, parental investment of cortisol and heat shock proteins (HSPs), larval offspring stress responses, and both parental and offspring heat and hypoxia tolerance. Parental exposure to the combined stressor did not affect fecundity, but increased mortality, transiently reduced offspring size, and delayed hatching. The combined treatment also reduced maternal deposition of cortisol and increased embryohsf1,hsp70a, HSP70,hsp90aa,and HSP90 levels. In larvae, while basal cortisol levels did not differ between treatments, acute exposure to combined heat stress and hypoxia increased cortisol levels in control larvae but had no effect on larvae from exposed parents. In contrast, whereas larval basalhsf1, hsp70a,andhsp90aalevels differed between parental treatments, the combined acute stressor elicited similar transcriptional responses across treatments. Moreover, the combined acute stressor only induced a marked increase in HSP47 levels in the larvae derived from exposed parents. Finally, combined hypoxia and elevated temperatures increased both thermal and hypoxia tolerance in adults and conferred an increase in offspring thermal but not hypoxia tolerance. These results demonstrate that intergenerational acclimation to combined thermal stress and hypoxia elicit complex carry-over effects on stress responsiveness and offspring tolerance with potential consequences for resilience.

The Salish Sea (BC, Canada) currently experiences ocean acidification (OA) well above levels predicted globally with climate change. Early life stages of herring have been found to be particularly impacted by OA, likely due to energetic costs associated with maintaining acidbase homeostasis under ocean acidification limiting development and growth. Pacific herring (Clupea pallasii), however, are intertidal spawners and embryos are often air exposed for hours, potentially offering a refuge from OA and providing excess oxygen. To investigate the effects of air exposure on CO2 tolerance, we reared Pacific herring embryos under three tidal regimes fully crossed with three aquatic CO2 levels and measured the effects on embryonic development and carryover effects on larval performance. Our data suggests that air exposure during low tide can be highly beneficial to intertidally spawning fishes and should be considered in climate change experiments and future models.

A11.27 EFFECTS OF HEAT STRESS AND OXIDATIVE STRESS EXPOSURE ON DIFFERENT LIFE STAGES OF COPEPOD CALANUS FINMARCHICUS.

Wednesday 5 July 2023

POSTER SESSION

Sidonie E. J. Rousseau (Norwegian University of Science and Technology, Norway), Elise Thiebaut (Norwegian University of Science and Technology, Norway), Dag Altin (Biotrix, Norway), Bjørn Henrik Hansen (SINTEF Ocean, Norway), Kang Nian Yap (Norwegian University of Science and Technology, Norway)

sidonie.rousseau@ntnu.no

To cope with environmental challenges due to climate change and anthropologic activities, organisms must modulate their physiology to survive. Various environmental stressors like heat and acidification have been suggested to cause increased oxidative stress in animals. However, in many organisms with multiple life-stages like the Calanoid copepods, how different life-stages respond to environmental stressors and oxidative stress remains unclear. The planktonic marine copepod Calanus finmarchicus is a low trophic species, an important food source, and a keystone species in the ocean. Therefore, it is important to understand how they respond to stress. To investigate physiological and life-history effects of two critical life-stages of C. finmarchicus to heat stress and oxidative stress, we will expose eggs and adult copepodites to graded doses of paraquat, an oxidative stressor, and different temperatures. We will measure the eggs’ hatching rate, define the LC50 of paraquat, and quantify oxidative damage in both eggs and adult copepodites in response to both temperature and paraquat

A11.25 INTERGENERATIONAL PLASTICITY TO CYCLING HIGH TEMPERATURE AND HYPOXIA AFFECTS OFFSPRING STRESS RESPONSIVENESS AND TOLERANCE IN ZEBRAFISH

treatments. We will also examine oxidative repair mechanism such as glutathione reductase activity. We hypothesise that early life stage is more sensitive to oxidative stress than adult and has lower tolerance for temperature changes. A better understanding of how copepods respond to environmental changes and the physiological mechanisms underpinning these responses will help us predict marine ecosystem dynamics in relation to climate change.

A11.28 N-DIMENSIONAL LANDSCAPES: AQUATIC EMBRYOS AS MODELS FOR PHENOMICS

Wednesday 5 July 2023 POSTER SESSION

Oliver Tills (University of Plymouth, United Kingdom), James McCoy (University of Plymouth, United Kingdom), Ziad Ibbini (University of Plymouth, United Kingdom), John I Spicer (University of Plymouth, United Kingdom)

oliver.tills@plymouth.ac.uk

Phenomics is the acquisition of high-dimensional data on an organismwide scale and is an approach highly suited to tackling many of the challenges of experimental biology, and in doing so, to enable it to better tackle pressing global challenges. Biological development is a period of incredible spatial and functional change, making traditional approaches to its measurement unavoidably piecemeal and suboptimal. Consequently, we have been establishing aquatic embryos as models for phenomics, by enabling the high-throughput measurement of complex phenotypes throughout the process of development, using automated imaging and computer vision. We have established versatile opensource software and hardware enabling the automated high throughput measurement of large numbers of aquatic embryos. A key strength of this approach is the ability to use computer vision approaches to reimagine the phenotype, moving beyond traditional measures, by integrating all of an organisms’ observable characteristics into an n-dimensional landscape. The capability of this approach in performing and interpreting multi-stressor studies with developing organisms will be discussed, alongside exploration of how considering the phenotype as a continuous landscape, enables a new approach to studying this fundamental period of life.

MORPHOLOGY, EXCRETION AND

the central organ of multidirectional transport, energy metabolism and excretion and a deep mechanistic understanding for the physiology of this organ is essential to understand responses on the systemic level. Our results demonstrated that despite reductions in body size under decreased seawater pH conditions the size and the morphology of the midgut is not compromised. Microelectrode measurements demonstrated that midgut ionic regulation is slightly decreased by moderate acidification levels, while food has a strong impact on midgut physiology, including a stimulation of luminal alkalization and NH4 + excretion rates. In following experiments, the combined effects of acidification and food availability will be investigated. Therefore, sea urchin larvae will be raised under elevated pCO2 levels and given different concentration of food. Oxygen consumption and ammonia excretion rates will be measured. Morphological and molecular characterizations including gene expression analyses of midgut acid-base transporters and metabolic genes will be carried out to generate a link between organismic and the molecular responses. This comprehensive dataset will help to establish a concept for explaining the interaction between ocean acidification and different food regimes on the physiology of the digestive system of the sea urchin larva.

A11.30 DETERMINATION OF THE FUNDAMENTAL SALINE NICHE OF INFAUNAL BIVALVES FOR AQUACULTURE AND CONSERVATION

Wednesday 5 July 2023 POSTER SESSION

Nicole Stakowian (Universidade Federal do Paraná, Brazil), Carolina A Freire (Universidade Federal do Paraná, Brazil)

nicolestakowian@outlook.com

Wednesday 5 July 2023 POSTER SESSION

Femke Thoben (Christian-Albrechts-Universität zu Kiel, Germany), Marian YA Hu (Christian-Albrechts-Universität zu Kiel, Germany), Meike Thoben (Christian-AlbrechtsUniversität zu Kiel, Germany), Inga Petersen (ChristianAlbrechts-Universität zu Kiel, Germany)

femkethoben@gmx.de

Metabolic and developmental rates of marine larval stages were demonstrated to respond plastically to changes in food availability, and CO2-driven seawater acidification. In sea urchin larvae, the midgut is

The niche approach is useful for an estimate of how species and populations can react to environmental change. The purpose of this study is to delimit the fundamental saline niche of a native infaunal bivalve,Anomalocardia flexuosa, and relate the laboratory results to its field distribution in estuarine areas, i.e., its realized saline niche. Bivalves are able of isolate the soft parts from the environment by closing the valves; infaunal species can, in addition, take refuge in microhabitats (burrows). Thus, limits of saline niches can be more difficult to define for such animals. Clams were exposed individually (500 mL containers) to increase or decrease in salinity (3‰ steps), starting in the average salinity (25‰) recorded at their collection site, with or without sediment. Salinities used were: 13, 16, 19, 22, 25 (control), 28, 31, 34, 37 and 40‰. They were observed for valve opening and burrowing activity, after 4 and 24 hours. Results so far suggest that the most comfortable salinity range for the species is between 22 and 34‰ (total n = 140, n with sediment = 8/salinity, n without sediment = 6/salinity; mean shell length = 2.6 mm ± 0.3, SD). Within this range they burrow completely, display clear osmoconformation, and keep tissue hydration. When in salinities <22‰ and >34‰, they do not open their valves (to filter) and do not burrow completely, despite being able to maintain tissue hydration. Such data can help to feed models of distribution and availability of suitable habitats (including farms).

A11.29

IONIC REGULATION OF THE ALKALINE LARVAL SEA URCHIN MIDGUT IS DIFFERENTIALLY AFFECTED BY FOOD AND SEAWATER ACIDIFICATION

A11.31 CAN PARENTAL HEATHARDENING IMPROVE PERFORMANCE OF MARINE INVERTEBRATES UNDER WARMING CONDITIONS?

Wednesday 5 July 2023 POSTER SESSION

Ahmed S. A. Abbas (University of Plymouth, United Kingdom), John I Spicer (University of Plymouth, United Kingdom), Robert Ellis (University of Plymouth, United Kingdom), Michael Collins (University of Plymouth, United Kingdom), Manuela Truebano (University of Plymouth, United Kingdom) ahmed.abbas@plymouth.ac.uk

Parental environment can affect the phenotypes of their offspring. Heat hardening has been shown to alter the responses of some marine invertebrates to warming and may improve their thermal performance. However, warming effects on offspring is, by contrast, unexamined. Consequently, we investigated the effects of parental hardening on the offspring performance of the European abalone,Haliotis tuderculata. Adults were acclimated to two parental conditioning treatments: a control group kept under average year temperature and a group exposed to two heat-hardening (thermal shocking) events during the conditioning period but maintained under the average year temperature outside of the hardening events. We compared shell size, hatching, aerobic metabolism, settlement, and survival rates of offspring under ambient and warmed conditions for each parental treatment. Offspring from heat-hardened parents showed better performance under warmed conditions but similar performance under ambient conditions compared with the control group. They exhibited higher growth and survival rates in the post-larval stage and higher growth rates in 80-dayold juveniles. There were no significant differences in hatching and settlement rates. We suggest that the differences in phenotypic traits were due to metabolic adjustments through parental hardening that optimized the costs for development and warming resistance. Our study highlights the potential of parental heat-hardening as a tool to help marine invertebrates coping with increases in ocean temperatures.

A11.32 FIT MUMS AND GIFTED OFFSPRING:

Wednesday 5 July 2023

POSTER SESSION

Luca Pettinau (Department of Biology University of Turku, Finland), Tytti Uurasmaa (Department of Biology University of Turku, Finland), Eila Seppänen (Natural Resources Institute Finland (Luke), Finland), Jenni M. Prokkola (Natural Resources Institute Finland (Luke), Finland), Amelie Crespel (Department of Biology University of Turku, Finland), Katja Anttila (Department of Biology University of Turku, Finland)

lupett@utu.fi

Rearing fish in hatcheries for stocking is common conservation tool for salmonids. However, hatchery fish have difficulties coping with natural conditions having low survival in the wild. One reason for this could be that current brood-stock rearing conditions do not allow fish to display their normal swimming behaviour which negatively affect

their cardiorespiratory physiology. As cardiac functions are strongly related to the capacity of fish to handle high temperatures, hatchery fish might be also vulnerable to heat-waves, reducing their survival prospects in the wild even more. Recent studies have shown that aerobic exercise training can improve cardiac function and cardiac thermal tolerance in farmed fish. However, it is unknown whether the benefits of exercise training might be transmitted to the next generation. Therefore, our aim was to investigate the effects of training on cardiac thermal performance of adult brown trout and test for the occurrence of transgenerational inheritance of fitness related traits. We trained the mothers with two different water flow conditions: a control program (0.2 bl/s) and exercise training program (0.7 bl/s for 6h per day) and assessed their cardiac thermal performance and reproductive success. Thereafter we examined the survival rate, cardiac thermal performance, CTMAX and body size of the offspring at different life stages, as well as the heritability of CTMAX and body size. Maternal exercise training improved embryos survival, growth and heritability of length and CTMAX in the offspring. By combining these different approaches, this project is providing new insights on the determinants of fish thermal tolerance.

MATERNAL SWIMMING EXERCISE IMPROVES EMBRYOS SURVIVAL, GROWTH AND HERITABILITY OF CTMAX IN JUVENILE BROWN TROUT.

A12 OPEN BIOMECHANICS

ORGANISED BY: NICOLAI KONOW (UNIVERSITY OF MASSACHUSETTS)

-45°

A12.1 ANALYSIS OF WAKE FLOW IN FISH SCHOOLING BY DUAL-LAYER PIV

Tuesday 4 July 2023 09:00

Go Eguchi (Graduate School of Fisheries Sciences Hokkaido University, Japan), Shinsuke Torisawa (Faculty of Agriculture

Kindai University, Japan), Kohsei Takehara (Faculty of Science and Engineering Kindai University, Japan), Tsutomu Takagi (Faculty of Fisheries Sciences Hokkaido University, Japan)

eguchi.go.x4@elms.hokudai.ac.jp

Fish receive hydrodynamic advantage of energy saving when fish swim in schooling. Fish push fluid backwards by tail-beating and get thrust force by the reaction. Wake flow induced by tail-beating makes reverse Kármán vortices. Follower fish could get the advantage of thrust, if the follower used the reduction of experienced flow velocity and local pressure caused by the leader fish. The visualization method, Particle Image Velocimetry (PIV) help to analyse the flow field. The impulse of vortex rings made by tail-beating are analysed by PIV. However, the analysis of fish schooling flow field means that it is necessary for several individuals to stay in two-dimensional cross-section irradiated by a laser light source at the same time. It is problematic to guide fish into the visualized area because of their avoidance behaviour towards intense light. Furthermore, the simultaneous visualisation of two or more individuals is instantaneous, which limits the analysis. In this study, we used two laser light sources which have different wavelengths and lens filters on high-speed camera, we visualised wake flow in dual-layer upper and lower. The visualisation area was increased vertically to improve the possibility of multiple individuals staying in same layer at the same time, and the wake and vortices were visualised when fish swim in parallel, to investigate how the flow field by the leader individual can affect the follower individual.

A12.2 TABLETOP MEASUREMENTS OF THE WAKE INDUCED BY A SWIMMING SNAKE

Tuesday 4 July 2023 09:00

Vincent Stin (MNHN, France), Ramiro Godoy-Diana (PMMH, France), Xavier Bonnet (CEBC, France), Anthony Herrel (MNHN, France)

vincent.stin@espci.fr

Experimental observations of the three-dimensional wake ofswimmers are scarce. This study provides the first experimental measurements of the three-dimensional vortical structuresof a swimming snake. A volumetric velocimetry (DDPTV) setup was used to quantify the wake of freely swimming snakes of different species and lifestyles in a laboratory. The snakes swam by oscillating their bodies with an amplitude increasing from head to tail. The volumetric measurements

show that the oscillations induced the creation of multiple vortices along the body. The three-dimensional structure of the vortices was in most cases paired vortex tubes. Some of them eventually linked to form a hairpin-like structure. These observations are in accordance with what has been predictedby computational fluid dynamic studies of other anguilliform swimmers. Our results provide a baseline to compare the wake structures of snakes with different morphologies and ecologies and to investigate the energetic efficiency of anguilliform swimming.

A12.3 SAVING ENERGY THROUGH BURST-AND-COAST SWIMMING NEEDS OPTIMIZATION

Tuesday 4 July 2023

09:30

Gen Li (Japan Agency for Marine-Earth Science and Technology, Japan), Dmitry Kolomenskiy (Skolkovo Institute of Science and Technology, Russia), Ramiro Godoy-Diana (ESPCI Paris, France), Benjamin Thiria (ESPCI Paris, France)

ligen@jamstec.go.jp

Some species of fish adopt a burst-and-coast swimming mode, during which they alternate between undulating body and holding straight. The burst-and-coast swimming mode is hypothesized as a strategy to improve energetical efficiency, but more difficult for quantitate investigation than the continuous swimming, since it involves additional kinematic parameters. In this study, we perform an experimental and numerical investigation on red-nose tetra fish that swim using the body and caudal fin (BCF) propulsion to quantitatively determine the relationship between burst-and-coast gait parameters and the swimming performance, as well as the role of the burstand-coast swimming in maximizing the energetical efficiency.

In the experiment, fish are forced to swim in a flume at a given velocity, and video recordings are used to examine changes in the gait as the imposed velocity changes. The results show how fish modulate their burst-and-coast gait parameters as swimming velocity changes, and that the fish adapt the burst-to-coast ratio keeping the time of a typical burst-and-coast event within a narrow range.

In the simulations, we developed a two-stage protocol in which we first model a series of long burst-and-coast runs with a range of amplitudes and frequencies for the fish undulations, and then cut and paste snippets from this simulation database to recreate arbitrary burst-and-coast patterns. This approach allowed us to make a detailed comparison between the efficiencies of burst-and-coast and continuous swimming. We found that the burst-and-coast swimming can require less energy than continuous swimming, but the strategy can turn very inefficient if not sufficiently optimized.

A12.4 THE BIOMECHANICS AND HYDRODYNAMICS OF SUBMERGED SWIMMING IN DUCKS

Tuesday 4 July 2023 09:45

Hagar Naomi Csillag (Tel Aviv University, Israel), Gal Ribak (Tel Aviv University, Israel)

hagar502@gmail.com

Waterfowl use webbed feet to propel their body on and below the water surface. Paddling is considered a form of drag-based propulsion, but fast swimming diving birds have been shown to use hydrodynamic-lift generated by their feet to propel the body underwater. The presence of such lift-based propulsion in slow swimming birds remains questionable. We Studied the submerged swimming of two duck species. Mandarin ducks (Aix gelericulata) are mostly surface swimmers whereas Ferruginous Pochards (Aythya nyroca) are divers that feed underwater. We trained both species to swim horizontally at 1m depth and filmed their paddling motion using high-speed cameras. Both species swam at similar swimming speed but pochards tilted their body (pitch) while swimming horizontally, whereas Mandarin ducks swam with their body aligned with the swimming direction. Consequently, the foot trajectory of the pochards was mostly vertical relative to water whereas it was both horizontal and vertical in the mandarin ducks. Mandarin ducks always used alternate paddling whereas Pochards used either synchronised or alternate paddling. A simple biomechanical model shows that the power phase of the paddling cycle generates both vertical forces and forward thrust to counter the buoyancy and hydrodynamic-resistance acting on the body. In the first half of the power phase the foot produces mostly drag-based thrust, whereas in the second half of the power phase lift contributes to propelling the body forwards. Thus, forward swimming ducks transition from drag to lift-based propulsion in each paddling cycle to achieve a force equilibrium during submerged swimming.

A12.5 STAYING BUOYANT UNDER PRESSURE:

AND PH RESPONSIVE RESILIN

Tuesday 4 July 2023 10:00

Evan K. G. McKenzie (The University of British Columbia, Canada), Tianxiao Ma (The University of British Columbia, Canada), Adrian Grzedowski (The University of British Columbia, Canada), Dan Bizzotto (The University of British Columbia, Canada), Phil G. D. Matthews (The University of British Columbia, Canada)

emckenzie@zoology.ubc.ca

Phantom midge larvae (Diptera:Chaoborus) are the world’s deepest free-diving insects, with one species diving >200 meters below the surface of Lake Malawi. Lake-dwelling Chaoborus dive to escape from fish during the day, hiding in lake sediments or the hypoxic hypolimnion before ascending again at night. They make this daily journey not by swimming but by adjusting the volume of two pairs of internal air-filled sacs to either rise or sink. These air-sacs are analogous to the swim bladders of fish, but we have shown that their

volume is regulated using a unique mechanism: the pH-induced expansion and contraction of bands of resilin within the air-sac wall. Unlike a fish’s swim bladder which is gas-impermeable and supported by internal gas pressure, the air-sac wall is gas permeable, so the gas pressure within equilibrates with that of the surrounding water, which is approximately one atmosphere regardless of depth. Therefore, the air-sac wall must resist collapse under hydrostatic pressure (over 20 atmospheres at 200 m), and we have used air-sac crush pressure to show maximum dive depth across species and air-sac geometries. But the resilin within must also generate a force that overcomes this pressure, expanding the air-sacs for the larva to ascend. To determine the mechanical work air-sacs perform as increasing pH causes them to expand against pressure, we have manipulated both pressure and pH in a sealed electrochemical chamber. We show that larger air-sacs from a deeper diving species produce more work against pressure over a given change in pH.

A12.6 TURBULENCE COMPENSATION BY WINDHOVERING KESTRELS

Tuesday 4 July 2023 10:15

George C Yi (University of Bristol, United Kingdom), Matthew Penn (RMIT, Australia), Mario Martinez Groves-Raines (RMIT, Australia), Simon Watkins (RMIT, Australia), Shane Windsor (University of Bristol, United Kingdom), Abdulghani Mohamed (RMIT, Australia)

Kestrels can fly very steadily into the wind, even in turbulent conditions, and hold station relative to the ground, a behaviour known as windhovering. We are interested in how the birds morph their wings and tail to control their flight in these conditions. We used a markerbased motion tracking system to capture the kinematics of nankeen kestrels (Falco cenchroides, n=2) trained to hang fly in a wind tunnel at low, medium and high turbulence conditions. We found that while windhovering, the kestrels could hold their heads very steady (less than 3mm displacement) regardless of the turbulence level. The birds used a similar mean pose under all turbulence conditions, with a reduced mean wing anhedral in higher turbulence conditions. As the turbulence level increased, the birds increased the compensatory wing and tail motions. We also found that the birds could fly with various body yaw angles using different asymmetric configurations. We hypothesize that this behaviour is related to the regions of visual acuity in their visual system. Together these results provide insight into turbulence compensation for small-scale uncrewed air vehicles, which typically struggle in turbulent conditions.

A12.7 THE NEUROMUSCULAR CONTROL OF BLOWFLY FLIGHT

Tuesday 4 July 2023 13:30

Scott R Dixon (University of Leeds, United Kingdom), Natalie E Doody (University of Leeds, United Kingdom), Graham Askew (University of Leeds, United Kingdom), Simon M Walker (University of Leeds, United Kingdom)

emmanuel.demargerie@univ-rennes1.fr

The flight machinery of insects is highly specialised, permitting the

AQUATIC CHAOBORUS LARVAE FLOAT MID-WATER USING TRACHEAL AIR-SACS

aerial agility and fine motor control that has allowed insects to exploit habitats across the globe. The primary power-producing flight muscles, the dorso-ventral and dorso-longitudinal muscles, power the upstroke and downstroke respectively, by causing cyclical deformations of the thorax. The physiology of these muscles is well-understood; however, they are not responsible for the asymmetric flight manoeuvres that insects perform. Such finer alterations to wing kinematics are controlled by several smaller muscles, known as steering muscles, which attach to cuticular invaginations known as sclerites. However, the complexity of the arrangement of these muscles makes it difficult to infer their function purely based on where they insert. Previous studies utilising electrophysiology, and more recently calcium imaging, have explored the role that these muscles play in flight kinematics, however, the picture remains incomplete. For example, practically nothing is known about how these muscles are involved with wing initiation at take-off, or how they control the wing’s pitch angle. This study combined thinwire electromyography with high-resolution, high-speed filming of Calliphora vicina blowflies using four cameras simultaneously. Both flight initiation and in-flight manoeuvres were recorded, the latter being induced by wide-field pitch, roll and yaw visual stimuli. The activity of individual muscles and the role they play in controlling wing kinematics on a stroke-by-stroke basis could therefore be fully assessed.

A12.8 THE FLIGHT MECHANICS OF THE DRINKING BEHAVIOUR IN COMMON SWIFTS (APUS APUS)

Tuesday 4 July 2023 13:30

Emmanuel De Margerie (CNRS, France), Geoffrey Ruaux (Rennes University, France), Kyra Monmasson (Rennes University, France), Tyson L Hedrick (University of North Carolina, United States), Sophie Lumineau (Rennes University, France)

cbucking@yorku.ca

To drink, common swifts glide down to water bodies, skim the surface without stopping, and use flapping flight to regain height. We measured the 3D trajectories of drinking swifts in the field, using rotational stereovideography (RSV). We tried to understand how swifts manage their flight height and speed in the seconds before they hit the water. Based on an energy saving hypothesis, swifts should strive to conserve their mechanical energy, by converting potential energy to kinetic energy, and touching water with an increased speed. This strategy would allow birds to regain height after drinking by converting kinetic energy back to potential energy, with minimal additional muscular work. This is not what we found, as swift dissipated mechanical energy by actively braking before hitting the water. Within the limits of our data, we try to describe how swift achieve braking, and discuss the possible causes underlying this behaviour. Our results illustrate that the flight behaviour of common swifts is not under the sole influence of energetic optimization, but that other constraints, probably related to flight control and safety, compete with energy saving.

Tuesday 4 July 2023

14:00

Jialei L Song (Dongguan University of Technology, China), Jorn Cheney (University of Southampton, United Kingdom), Changyao Chen (Dongguan Univeristy of Technology, China), Richard Bomphrey (Royal Veterinary College, United Kingdom), James Usherwood (Royal Veterinary College, United Kingdom)

songjl@dgut.edu.cn

Bird can transit between stable and unstable by substantially morphing wings and tail. Tail as an auxiliary lift surface, plays an important role on lift and drag production and also significantly affects the longitudinal stability. In this study, we reconstruct a high-fidelity barn owl model using the point cloud of its surface obtained from high-speed photogrammetry, and use computational fluid dynamics to simulate the flow around the bird. By virtually manipulating the tail to a series of postures of the barn owl, we analyse the aerodynamics and static stability for each tail posture. For simplification, only the tail pitch and spread are studied, with the tail spread angle ranging from zero to 41 degrees and the pitch angle ranging from 6 to 46 degrees. Our preliminary study shows that the barn owl gliding is unstable and the tail manipulation within above pitch and spread range can not switch from unstable to stable.

A12.10 ALANDING BEHAVIOUR OF BUMBLEBEES ON A MOVING FLOWER

Tuesday 4 July 2023

14:15

Lana J. De Vries (Wageningen University Research, Netherlands), Frank Van Langevelde (Wageningen University Research, Netherlands), Remco P.M. Pieters (Wageningen University Research, Netherlands), Simon Sponberg (Georgia Institute of Technology, United States), Florian T. Muijres (Wageningen University Research, Netherlands)

lana.devries@wur.nl

Bumblebees forage in a dynamic environment, where the flight conditions change continuously. For example, they must deal with changes in temperature, light conditions, and wind speed over the course of a day. Because of the variability in wind conditions, bumblebees have to be able to land both when the flowers are standing still, and when they are moving at different speeds. In this research, we studied the effect of flower movement on the landing behaviour of Bombus terrestris bumblebees. To do this, we build a one cubicmeter flight arena containing a horizontally moving artificial flower. The flower was programmed to alternate between sine movements at different speeds, and standing still as a control. Bumblebees from a hive connected to this flight arena were trained to land on the moving flower. Each time a bumblebee landed on the flower, this automatically triggered a video recording by a camera filming from above. By training a neural network using DeepLabCut, we tracked the position of the bumblebees and flower over time. Our results include the effect of flower movement on performance parameters such as landing speed and tortuosity of the trajectory, and how bumblebees align their movement with the sine movement of the artificial flower. This provides insight into the effect of flower movement on bumblebee landing behaviour, and increases our understanding of how bumblebees adapt their flight behaviour to deal with environmental conditions such as wind.

A12.9

TAIL MANIPULATION OF A BARN OWL CAN NOT SWITCH FROM LONGITUDINAL UNSTABLE STATUS TO STABLE IN GLIDING

A12.11 INVESTIGATION OF WING SHAPE AND BONE MORPHOLOGY IN RELATION TO UNSTEADY FLIGHT BEHAVIORS IN RAPTORS (ACCIPITRIFORMES)

Tuesday 4 July 2023 14:30

erik.sathe@biol.lu.se

Birds exhibit substantial variation in flight behavior. Often, different flight modes are used in association with ecological factors. In particular, habitat use and foraging strategy impart unique demands on birds’ flight abilities. Habitats with many obstacles or foraging strategies that involve aerial pursuit of prey both require birds to engage in highspeed maneuvers (i.e., non-steady flight), whereas open habitats and scavenging or terrestrial foraging require non-steady flight relatively less often. Due to the link between locomotion and morphology, it follows that birds along this spectrum of non-steady flight use should possess morphological variation in their flight apparatuses. We here investigate the wing morphology that underlays variation in flight behavior, particularly in how it pertains to non-steady flight. Non-steady flight is often associated with low aspect ratio wings and requires activation of muscles that either originate or insert on the radius and ulna. Therefore, we hypothesize that radius and ulna morphology as well as external wing shape are related to the relative use of non-steady flight modes. We tested this hypothesis among species within raptors (the order Accipitriformes) because there is great diversity in the relative use of non-steady flight modes among species in this order. We quantified variation in ulna and radius morphology using 3-dimensional geometric morphometrics and we measured external wing shape. We then used phylogenetic comparative methods to uncover relationships between wing morphology, habitat, and foraging behavior. Our early findings suggest possible relationships among habitat use, foraging mode, wing bone shape, and external wing morphology.

A12.12 AVIAN INSPIRED GUST SOARING MANOEUVRE IDENTIFICATION IN URBAN FLIGHT

Tuesday 4 July 2023 14:45

Freddie Turner (Bristol Robotics Laboratory (University of Bristol and University of the West of England), United Kingdom), Shane Windsor (University of Bristol, United Kingdom), Luca Giuggioli (University of Bristol, United Kingdom)

freddie.turner@bristol.ac.uk

Birds can interact with the surrounding airflow to increase their total usable energy, a behaviour known as soaring flight. Thermal soaring, for example - where birds circle in a column of rising air for a ‘free ride’ to higher altitudes - is a common and instantly recognisable phenomenon. Birds can also gain energy by exploiting the wind gradients of nonuniform flow fields, increasing their air-relative speed and hence kinetic energy by moving between different regions of the flow. Seabirds such as albatross and shearwater are frequently observed to perform such dynamic soaring manoeuvres in the large-scale and

predictable wind shear above the ocean, but the same effect can also apply on smaller scales and for stochastic temporal variations in the wind (gusts). In particular, the complex wind fields of urban environments provide rich opportunities for gradient-based energy extraction. Using a model of lesser black-backed gull flight dynamics and urban wind field CFD simulations, a previous study generated a collection of wind-aware urban flight trajectories optimised for energy gain. Time series projection, clustering and motif discovery techniques have been applied to this dataset in search of prototypical gust-energy extraction manoeuvres, in order to find common patterns exploited by the optimiser for energy gain within the structured flows of the urban environment. These air-relative manoeuvres give insight into the behaviours birds may be using to extract energy and can form the basis of gust soaring control algorithms for small autonomous flying vehicles.

A12.13 ODONATA FLIGHT: MECHANICAL STUDY OF THE WINGS

Tuesday 4 July 2023 15:30

Camille Aracheloff (Muséum National d'Histoire Naturelle, France), Romain Garrouste (Muséum national d'Histoire naturelle, France), André Nel (Muséum national d'Histoire naturelle, France), Ramiro Godoy-Diana (École Supérieure de Physique et de Chimie Industrielles, France), Benjamin Thiria (École Supérieure de Physique et de Chimie Industrielles, France)

camille.aracheloff@mnhn.fr

Odonata (dragonfly and damselfly) exhibit impressive flight abilities. They can perform many different manoeuvres such as zigzags, linear back and forth motion, sharp turns and quick accelerations. Those trajectories are the results of complex fluid-structure interactions where wing morphology has a prominent role, as shown in previous studies. Insect wings are heterogeneous structures composed of an elastic membrane and a network of veins that control the local stiffness of the wing. The size, geometry, vein pattern, and other wing characteristics strongly vary across the different phylogenetic lineages. We aim at understanding the role of the different wing’s characteristics on the aerodynamic force production and connecting them with flight modes of dragonflies. Such results could be extrapolated in evolutionary perspective, starting from early apparitions of the first Odonatoptera in the early late Carboniferous. In this work, we perform a comparative study of dragonfly wings from 14 genres using vibrational tests to determine the resonance frequency. We then examine the variation of those resonance frequencies with respect to key wing parameters such as the aspect ratio, the relative positions of the nodus and pterostigma.

A12.14 OPTIMISED FLAPPINGWING STROKE CONFIGURATIONS HELP COUNTERACT TRAJECTORY PERTURBATIONS IN DIRECTED GUSTS

Tuesday 4 July 2023 15:30

Timothy R Jakobi (RMIT, Australia), Alex Fisher (RMIT, Australia), Sridhar Ravi (UNSW, Australia), Simon Watkins (RMIT, Australia)

Erik A Sathe (Lund University, Sweden), Per Henningsson (Lund University, Sweden)

t.jakobi@adfa.edu.au

The variations in the wing motion profiles of flying insects seem to enable remarkable steadiness when flying in unsteady atmospheric conditions. Small changes in wing motion throughout a flapping stroke enable the body to engage in agile maneuvers as it passes through aerial interferences. We used high-speed footage of bumblebees flying in four different flow conditions and tracked wing motions throughout to reveal four unique wing stroke configurations. We developed an analytical model to estimate the force generated by the wings in each of the stroke configurations and examined their effects on the body. After summing the forces from both wings, each stroke configuration was found to generate counteractive forces and moments against the perturbations induced by each corresponding gust case. In upward and sideward gusts, bees commonly configured the motion range to the aft part of the stroke, resulting in counteractive forces and moments. In downward gusts, this was only possible by modulation of the flapping frequency due to an apparent limitation in shifting the motion range forward. Simultaneous production of counteractive forces and moments may therefore be challenging in downward gusts due to the opposing components of aerodynamic force arising from wing translation and gust flow throughout the stroke. The opposite was true in upward gusts, which afforded more controllability in generating favorable forces, demonstrating why trajectory perturbations were generally less in upward gusts. These results shed light on how flying insects maintain stability in complex environments and offer potential strategies for intelligent MAVs to mimic such behavior.

A12.15 THE ALLOMETRY OF FLIGHT IN

HOVERFLIES

Tuesday 4 July 2023 16:00

Camille Le Roy (Wageningen University, Netherlands), Nina Tervelde (Wageningen University, Netherlands), Florian T. Muijres (Wageningen University, Netherlands)

leroy.camille7@gmail.com

Variation in size has pervasive influence on the performance of animals. Natural selection may favour scaling relationships between traits and size that improve performance in crucial behaviours such as escaping from predator or foraging. To understand the evolution of scaling relationships, it is thus crucial to study both how morphology and its use through behaviour scales with size. Here we focused on the hovering flight of hoverflies (Syrphidae), a behaviour directly impacting foraging efficiency in this nectar-feeding insects. Using stereoscopic high-speed videography, we compared the wingbeat kinematics of seven hoverfly species varying in body mass from 5 to 100 mg, and using high-resolution photography we characterized wing shape and size. Our study reveals changes in both the wingbeat kinematics and the wing shape enabling to maintain good hovering abilities across a range of species size. Specifically, we showed that the second moment of wing area is relatively lower in larger species (negative allometry). This change in wing shape in larger hoverflies is accompanied with a decrease in wingbeat frequency, primarily due to lower wing angular speed. These findings shed light on the joint evolution of body size, wing morphology, wingbeat kinematics and flight performance in hovering insects.

A12.16 FLIGHT KINEMATICS OF SWARMING MALARIA MOSQUITOES

Tuesday 4 July 2023 16:15

Antoine Cribellier (Wagningen University, Netherlands), Serge Poda (Institut de Recherche en Sciences de la Santé (IRSS), Burkina Faso), Florian Muijres (Wagningen University, Netherlands)a)

antoine.cribellier@wur.nl

With the growing resistance of wild mosquitoes against insecticides, it is becoming more and more urgent to find efficient alternatives to control the population of these dangerous disease vectors. One method, the sterile insect technique (SIT), is particularly promising. But this method is based on the idea that lab reared sterile males, which are released in the wild, also stay sexually competitive. To asses the potential of this vector control technique, we need a better understanding of the in-swarm mosquito mating behaviour. To find a mate, malaria mosquitoes gather in swarms at sunset. First, the males mosquitoes gather above a swarm marker, often an object contrasting visually with the surroundings such as a patch of grass. After a few minutes, female mosquitoes start to approach the swarm, where they form mating copula with a male, which then leave the swarm. Our knowledge of mosquitoes swarm dynamics and interactions between individuals is mostly based on visual observations, which can only produce limited quantitative data. Here, we used stereoscopic videography-based tracking to reconstruct the three-dimensional flight kinematics of male malaria mosquito (Anopheles coluzzii), swarmingin the lab. We triggered the swarming behaviour using simulated sunset conditions and a black ground marker. Using these data, we quantified the spatial and temporal dynamics of flight behaviour of individual mosquitoes in the swarm, and how the swarming mosquitoes interacted with each other.

A12.17 FLOW AND WING KINEMATICS MEASUREMENTS OF A TINY INSECT IN FLIGHT

Tuesday 4 July 2023 16:30

Evan J Williams (University of South Florida, United States), John Murray-Bruce (University of South Florida, United States), David W Murphy (University of South Florida, United States)

evanwilliam@usf.edu

Tiny sub-millimetre insects in flight use the clap and fling mechanism to generate lift, but the aerodynamics are not well understood owing to the small spatial and fast temporal scales involved and the difficulty of experimentally observing the flow around the insect’s wings. To examine tiny insect flight, we implemented a novel ultra-high speed brightfield μPIV system to measure time-resolved (10kHz) flows generated by a freely flying tobacco whitefly (Bemisia tabaci). A computational algorithm was developed to extract in-focus particles and suppress noise in PIV images by solving the sparsityregularized inverse problem that arises when a Gaussian function is used to model each particle’s intensity morphology. Additionally, two orthogonally positioned and temporally synchronized cameras were used to implement 3D stereophotogrammetry to determine the insect’s position in the PIV measurement plane and measure 3D wing kinematics and body kinematics. The whitefly has a body length

of 0.8 mm, forewing length of 0.9 mm, hindwing length of 0.75 mm, stroke amplitude of 123º, beat frequency of 150 Hz and chordwise Reynolds number of 14. The forewing and hindwing have distinct wing trajectories and non-synchronized Euler angles throughout the stroke. We present flow fields produced by a freely flying tiny insect which reveals a downwards jet ejected from between the wings with flow speeds up to 500 mm/s, a medial spanwise flow during the fling mechanism as the wings create a V-shaped gap, well-developed flows attached to the wing during the power stroke, and recirculation occurring during stroke reversal.

A12.18 HIGH-PRECISION KINEMATICS OF ANOPHELES GAMBIAE WITH INCREASING TEMPERATURE

Tuesday 4 July 2023 16:45

Rachel H S Tran (University of Leeds, United Kingdom), Simon M Walker (University of Leeds, United Kingdom) bsrhst@leeds.ac.uk

Mosquitoes are major vectors of disease, which thrive in warm climates. In order to manage mosquito populations, it is therefore important to monitor their response to temperature change, to better predict and interrupt their life cycle. From a kinematic and aerodynamic perspective, little is known regarding how they manoeuvre with their high aspect ratio wings and wingbeat frequencies. Here, we recorded male and female Anopheles gambiae using a ten high-speed camera setup at 12,000 fps, and separate stereo cameras as a trigger system to detect movement in the free-flight arena. A completely automated voxel-carving package was then used to get high-precision wing and body kinematics (mid-wing pitch angle, wing torsion and body roll) when flying with increasing ambient temperature (20 to 35 °C). Males flapped consistently faster than females, reaching up to 1,012 Hz at the highest recording temperature. Stroke amplitude decreased with increasing temperature and reduced to even lower amplitudes (13.8 °) than those previously reported in literature. There was no correlation between wing length and wingbeat frequency, and wing speed remained constant with increasing temperature. Data collected here may inform the development of acoustic lures, provide some insight on migration patterns with climate change and feed into the most accurate aerodynamic modelling methods to date with wing deformation such as computational flow dynamics.

THE

Wednesday 5 July 2023 09:00

Callum J McLean (Callum J McLean, United Kingdom), Charlote A Brassey (Manchester Metropolitan University, United Kingdom), Michael Seiter (University of Vienna Naturhistorisches Museum Wien, Austria), Russell J Garwood (University of Manchester Natural History Museum, United Kingdom), James D Gardiner (Manchester Metropolitan University, United Kingdom)

callum.mclean.research@outlook.com

The link between form and function is key to understanding the evolution of unique and/or extreme morphologies. Amblypygids, or whip spiders, are arachnids that often have highly-elongated spined pedipalps. These limbs are used to strike at, and secure, prey items before processing by the chelicerae. Amblypygi pedipalps are multifunctional, however, also being used in courtship and contest, and vary greatly in form between species. Increased pedipalp length may improve performance during prey capture, but length could also be influenced by factors including territorial contest and sexual selection. Here for the first time we use high speed videography and manual tracking to investigate kinematic differences in prey capture between amblypygid species. Across six morphologically diverse species, spanning four genera and two families, we create a total dataset of 86 trials. Prey capture kinematics vary considerably between species, with the main differences being expressed in pedipalp joint angle ranges. In particular, maximum reach ratio does not remain constant with total pedipalp length, as geometric scaling would predict, but decreases with longer pedipalps. This suggests that taxa with the most elongated pedipalps do not deploy their potential length advantage to proportionally increase reach. Therefore, a simple mechanical explanation of increased reach does not sufficiently explain pedipalp elongation. We propose other factors to help explain this phenomenon, such as social interactions or sexual selection, which would produce an evolutionary trade-off in pedipalp length between prey capture performance and other behavioural and/or anatomical pressures.

A12.20 XROMM ANALYSIS REVEALS COMPLEX MOVEMENTS OF BEAK AND TONGUE DURING SEED PROCESSING IN CANARIES

Wednesday 5 July 2023 09:00

Maja Mielke (University of Antwerp, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium) maja.mielke@uantwerpen.be

Granivorous songbirds rely on seeds as a major food source, but the efficient removal of the indigestible husk of large seeds poses a major challenge. Removing the husk while leaving the energy-rich kernel intact requires accurate beak movements tuned to the position and orientation of the seed. In order to study these beak movements in small songbirds, we used marker-based X-ray Reconstruction of Moving Morphology (XROMM) in domestic canaries feeding on hemp seeds. This method allowed us to quantify the three-dimensional movement of upper and lower beak, tongue, and seed in unprecedented detail. We show that dorsiflexion of the upper beak (cranial kinesis) contributes considerably to total gape angle, but to varying extent depending on the phase of the feeding cycle. Furthermore, the birds make use of pronounced mandible movements in all three dimensions, which allows for fine-tuning of the interaction between beak and seed. Finally, the canaries utilise different tongue movements for different tasks during

A12.19

KINEMATICS OF AMBLYPYGID (ARACHNIDA)

PEDIPALPS DURING PREDATION: EXTREME ELONGATION IN RAPTORIAL APPENDAGES DOES NOT RESULT IN A PROPORTIONATE INCREASE IN REACH AND CLOSING SPEED

seed processing. Firstly, the tongue moves in all three dimensions in correlation with beak oscillation during seed positioning. Secondly, it is held more steady while supporting the seed during biting attempts. Thirdly, the tongue performs extensive rostro-caudal movements for transporting the kernel to the oesophagus after husk removal. We will discuss how the coordinated, fast, and complex 3D-movements of beak and tongue facilitate the efficient processing and dehusking of seeds.

A12.21 DEVELOPMENTAL BIOMECHANICS IN LEAF-CUTTER ANTS

Wednesday 5 July 2023 09:30

Frederik Püffel (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

fp4418@ic.ac.uk

Many social insects display age polyethism: young workers stay inside the nest, and only older workers go out to forage. This behavioural shift is often accompanied by genetic and physiological changes, but the mechanistic origin of it remains unclear. To investigate whether the mechanical demands of foraging effectively prevent young workers from partaking in it, we studied the biomechanical development of the bite apparatus in Atta vollenweideri leaf-cutter ants in the days after eclosion. Fully-matured foragers generated peak in-vivo bite forces of around 100 mN, more than one order of magnitude in excess of those measured for freshly-eclosed callows of the same size. This change in bite force was accompanied by a sixfold increase in the volume of the mandible closer muscle, and by a substantial increase of the flexural rigidity of the head capsule, driven by a significant increase in both average thickness and indentation modulus of the head capsule cuticle. As a result of this development, fully-matured foragers have likely gained the biomechanical ability to cut most tropical leaves, whereas freshly-eclosed callows may cut almost none: their muscles do not yet generate sufficiently large bite forces, and their head capsule is so compliant that large muscle forces may inflict damaging deformations. On the basis of these results, we speculate that continued biomechanical development post eclosion may be a key factor underlying age polyethism, wherever foraging is associated with mechanical demands on the musculoskeletal system.

suggests some form of cranial kinesis. These morphological traits have been linked to the high-speed running and leaping of rabbits and hares to reduce weight, improve vision, reduce shock, and protect the sensory organs during impact. However, very little work has been done on their biomechanical performance. Here, we use finite element analysis to model the forces of mastication and the neck muscles in a range of lagomorph taxa spanning difference sizes, locomotor styles and diets. Results show that the majority of the cranium, including the fenestrated rostrum, transmits masticatory strains. However, in leporids there is a marked boundary dividing the anterior and posterior regions of the skull at the site of the intracranial joint, indicating a functional modularity between these areas: the anterior region being specialised for feeding, while reducing weight, and the posterior region allowing ventral flexion of the skull, expansion of the auditory bulla, and possibly protecting the skull from impacts by allowing a degree of cranial kinesis. This analysis supports a biomechanical perspective on leporid ecology, and leads to more investigations on the relationship between form and function in lagomorphs.

A12.23 VARIATION IN FOOD MATERIAL PROPERTIES BETWEEN BRITISH RED SQUIRREL POPULATIONS

Wednesday 5 July 2023 10:00

Kim Chandler (University of York, United Kingdom), Philip G Cox (University College London, United Kingdom)

kec542@york.ac.uk

Wednesday 5 July 2023 09:45

Alana C Sharp (University of Liverpool, United Kingdom), Amber Wood-Bailey (University of Liverpool, United Kingdom)

alana.sharp@liverpool.ac.uk

The skull of modern leporid lagomorphs (rabbits and hares) is highly modified from other mammals, including their closest relatives the pikas (Ochotonidae), with a suite of unique features including fenestration of the rostrum and posterior cranial bones, a pronounced ventral flexion of the facial region, and an intracranial joint that

British red squirrels (Sciurus vulgaris) exist today in isolated populations, owing to the introductionof invasive grey squirrels (Sciurus carolinensis) and subsequent spread of squirrelpox virus. Previous research found distinct morphologies between populations, particularly in a managed population at Formby National Reserve, Merseyside, which has historically received supplementary feeding in the form of peanuts. It was assumed that the relative softness of this diet compared to a naturally available diet has been a driver of phenotypic change. However, before drawing this conclusion, it was necessary to first establish whether the diets of the different populations do indeed offer different mechanical challenges. Thus, in this study, we use a novel experimental method to establish the fracture properties of eight food items regularly consumed by squirrels, using values of toughness as a means for comparison. Previous studies have employed scissors placed between the platform and crosshead of a physical testing machine, with the food item placed between the bladesand compression applied. Here we use the same set-up but with nail clippers, to avoid the inconstant frictional forces of scissors between tests. The effects of caching (practice of burying items for later consumption) were also analysed. Results indicate that peanuts offer a much-reduced mechanical challenge for squirrels, providing further evidence that morphological change is likelylinked to diet. This may have implications for futures choices by conservation workers in provision of supplementary foods.

A12.24 CUTTING FORCE, CUTTING SPEED AND THE ADVANTAGE OF BODY SIZE IN ATTA CEPHALOTES LEAF-CUTTER ANTS

A12.22 DIVIDING FORCES: FINITE ELEMENT MODELLING OF CRANIAL TRAITS BETWEEN OCHOTONIDAE (PIKAS)AND LEPORIDAE (RABBITS AND HARES) LAGOMORPHS

Wednesday 5 July 2023 10:15

Olivia K Walthaus (Imperial College London, United Kingdom), Frederik Püffel (Imperial College London, United Kingdom), Finn Wagner-Douglas (University of Applied Sciences Bremen, Germany), Lina Rhmari Tlemçani (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

l.walthaus20@imperial.ac.uk

Leaf-cutter ants are the prime herbivores of the Neotropics. Using foraging parties which consist of workers that can differ drastically in size, they cut fragments from plant tissues to feed a fungus as a crop. Two key forces determine the ability of workers to cut a given plant material: the maximum force they can apply (bite force), and the force required to fracture the plant fragment (cutting force). The bite force is determined by the physiology and anatomy of the bite apparatus; the cutting force, in turn, depends on the structural and mechanical properties of the plant material, and mandible geometry. Previous work has shown that bite forces increase significantly with size, but how do cutting forces vary across both worker sizes and materials? To address this question, we used a custom-built fibre optic force setup to measure the forces required to cut the leaf lamina of four plant species and four synthetic substrates with different mechanical properties, using both forager mandibles (showing different states of wear) and pristine callow mandibles from workers across the size range. Cutting forces vary significantly between foragers and callows, but only weakly with mandible size. We speculate that the differential mechanical scaling of cutting and bite forces places larger workers at a putative advantage by conferring behavioural flexibility – the relatively larger forces allow relatively larger cutting speeds. We verify this hypothesis with cutting speed measurements in freely foraging ants.

A12.25 CEPHALOPODS FEEDING: THE GROWTH OF THE BUCCAL MASS IN SEPIA OFFICINALIS

Wednesday 5 July 2023 11:00

Louise Souquet (Department of Mechanical Engineering University College London, United Kingdom), Olivier Basuyaux (Synergie Mer Et Littoral, France), Gwendoline

Guichard (Synergie Mer Et Littoral, France), Anthony Herrel (Département AVIV UMR CNRS 7179 MECADEV CNRSMNHN 55 rue Buffon 75005 Paris, France), Isabelle Rouget (Centre de Recherche en Paléontologie-Paris (CR2P) Muséum national d’Histoire naturelle SUCNRS 43, France), Susan Evans (Centre for Integrative Anatomy Department of Cell and Developmental Biology University College Lon, United Kingdom), Mehran Moazen (Department of Mechanical Engineering University College London, United Kingdom)

l.souquet@ucl.ac.uk

Due to their small size, juveniles are more likely to be at a competitive disadvantage in their access to trophic resources. Therefore, compensation in feeding performance might be observed in younger specimens. To test that hypothesis in invertebrates, we investigated the link between ontogeny and feeding performance in the common cuttlefish Sepia officinalis. We explored the changes in beak shape, wear pattern, mechanical properties, muscular anatomy, and bite force during growth. We found that both upper and lower beaks present ontogenetic shape variation in the rostrum area that might be due to

wear induced by feeding. In addition, muscle development was found to differ between cuttlefish of different ages, resulting in juveniles having a muscular advantage for opening. The mechanical properties of the beaks in juveniles indicate greater resistance to stress compared to adults. Tanning observed on the beaks provides reinforcement to areas under high load during biting. Finally, an isometric relation was found in the bite force of S. officinalis, with no sign of feeding performance compensation in juveniles. Feeding performance thus does not reflect the ontogenetic shift from a crustacean-based diet in juveniles to a fish-based diet in adults. Hence, we propose a functional hypothesis explaining the observed pattern, suggesting that contrary to the initial hypothesis, small size may give mechanical advantage for the consumption of hard food items.

A12.26 A COMPARISON OF APPROACHES TO ESTIMATE MUSCLE FORCES, VALIDATED BYIN VIVOBITE FORCES.

Wednesday 5 July 2023 11:00

Samuel Ginot (Universität Bonn, Germany)

sginot@evolution.uni-bonn.de

Performance traits such as bite forces are crucial to individual fitness and relate to the ecological niche and adaptation of species. However, it is not always possible to directly measure bite forces. Biomechanically informed predictions of bite forces or other performance traits are therefore of high relevance to allow testing hypotheses of adaptation. Although biomechanical models are based on classical mechanics, combining forces, material properties, and laws of levers, it is currently unknown how various models relate to forces measured in vivo. One critical component of these models is the physiological cross-sectional area (PCSA) of muscles, which relates to the maximum amount of force that can be produced by a muscle. Here, using the grasshopper Schistocerca gregaria, we compare various ways to obtain PCSA values and use in vivo measurements of bite forces to validate the biomechanical models. We show that the dissection-based method performs well, with estimated bite forces in the range of in vivo bite forces, and tightly correlated to them. All 3D reconstructed PCSAs overestimate in vivo bite force, but nevertheless are correlated to them, except for PCSA based on muscle mesh volume, probably due to muscle shrinkage. While biomechanical models should ideally correlate with in vivo performance, we show that some of them over or underestimate in vivo forces, making them inadequate for absolute estimation of organismal performance without appropriate correction.

A12.27 CONSERVED MAMMALIAN MUSCLE MECHANICS DURING ECCENTRIC CONTRACTIONS

Wednesday 5 July 2023 11:30

Roger W. P. Kissane (University of Liverpool, United Kingdom), Graham N. Askew (University of Leeds, United Kingdom)

r.kissane@liverpool.ac.uk

Skeletal muscles have a broad range of biomechanical functions, ranging from functioning as a motor by generating force during fibre shortening to produce power, to functioning as a brake by being primarily active during muscle lengthening, generating negative power. The capacity of skeletal muscle to generate power is underpinned by the force-velocity relationship, which comprises two distinct components: a concentric and an eccentric force-velocity relationship. While the concentric force-velocity relationship has been extensively investigated across a range of phenotypically distinct muscles, scaling relationships and even in response to pathophysiological remodelling, the eccentric force-velocity relationship has been comparably less well studied. Despite identification of the relationship 70 years ago, no reliably comprehensive study has been undertaken to characterise this relationship in mammalian muscle. Subsequently, we have collated the most comprehensive data set to date on the concentric- and eccentricvelocity relationship in mammalian muscle. Using the phenotypically distinct fast extensor digitorum longus and slow soleus muscles from a mouse, we show that there exist differences in not only the concentric but also the eccentric force-velocity relationship. In addition, we propose a new method of characterising eccentric force-velocity profiles and validate this approach across mammalian skeletal muscles spanning three orders of magnitude in body mass. Here we provide evidence for a novel predictor of force-velocity characteristics that may be used to better inform musculoskeletal models and assess pathophysiological remodelling.

A12.28 THE MECHANICAL FUNCTIONAL OF PROXIMAL HINDLIMB MUSCLES IN RESPONSE TO CHANGING GRADIENT IN GALLUS GALLUS DOMESTICUS

Wednesday 5 July 2023 11:45

John C Marrin (University of Leeds, United Kingdom), Graham N Askew (University of Leeds, United Kingdom)

bsjmcm@leeds.ac.uk

The mechanical demands on the limb muscles changes with gradient. Net positive work is done during incline locomotion, energy is absorbed during decline locomotion, and during level locomotion, no net work is done. In many cursorial animals the distal muscle-tendon units have relatively short muscle fascicles and long extensible tendons. During level running the muscle fascicles operate isometrically and the tendons store and return mechanical energy over the course of a stride while. Whereas during incline running, the muscle fascicles actively shorten, generating net positive work. The morphology of the proximal limb muscle-tendon units is rather different from the distal limb muscles, with muscles possessing relatively long fascicles and short, stiff tendons. How these muscles operate during both level and gradient running is unknown.

The aim of this study was to investigate the mechanical function of three proximal, biarticular (crossing the hip and knee joints) hindlimb muscles of chickens during level, incline and decline locomotion: the iliotibialis lateralis pars preacetabular, iliotibialis lateralis pars postacetabular and iliofibularis. The length change of the muscle fascicles and their activity patterns were determined using sonomicrometry and electromyography, respectively, and limb kinematics were recorded using high-speed videography. The mechanical functions of the muscles were determined by measuring force generation in situ using the work loop technique to playback the length trajectories and activity patterns recorded in vivo. We present novel data demonstrating how the mechanical function of these hindlimb muscles varies over the course of the stride in relation to gradient.

A12.29 THREE-DIMENSIONAL ARCHITECTURE OF AXIAL MUSCLE FIBRES IN LARVAL FISH

Wednesday 5 July 2023 12:00

Noraly M.M.E Van Meer (Wageningen University, Netherlands), Martin J.M. Lankheet (Wageningen University, Netherlands), Henk Schipper (Wageningen University, Netherlands), Johan L. Van Leeuwen (Wageningen University, Netherlands)

noraly.vanmeer@wur.nl

The axial muscle fibres of adult bony fish are arranged in complex helical trajectories. Anteriorly, fibres make, on average, relatively large angles to the medial and horizontal planes (azimuth and elevation, respectively). This may enable approximately uniform strains across the transverse plane for particular body curvatures, supporting similar specific power contributions from all fibres. In the caudal peduncle, fibres run approximately parallel. These fibres primarily stiffen the tail to transmit power towards the tail fin, rather than generating considerable power, so adult axial muscles function differently along the fish. In the anal region of larval fish, the adult helical pattern is initially absent and develops over several weeks. However, the fibre orientations along the body are still unknown. To fill this gap, we made high-resolution 3D scans of 4 days post fertilisation (dpf) zebrafish larvae with fluorescent muscles. Variations in fluorescence level allowed segmentation of individual fibres, for which we quantified size and orientation. Results show that lateral muscle fibres are more slender than medial fibres, and that fibre orientation varies over both length and width of the body. Fibre elevation and azimuth angles seem more variable anteriorly than posteriorly, and, on average, the angle between fibres and the longitudinal axis of the fish decreases from anterior to posterior. Therefore, differences in muscle function along the body may already occur in fish of 4 dpf. This study lays the groundwork for understanding how larval fish rearrange their musculature during development, and how this influences their swimming performance.

A12.30 TENSILE MECHANICS OF SILK ARCHITECTURES: INDIRECT WEB ATTACHMENTS ARE STRONGER

Wednesday 5 July 2023 12:15

Daniele Liprandi (Universität Greifswald, Germany), Federico Bosia (Politecnico di Torino, Italy), Nicola M. Pugno (Università di Trento, Italy), Jonas O. Wolff (Universität Greifswald, Germany)

daniele.liprandi@uni-greifswald.de

Spiders are renowned for their ability to spin silk into specific architectures with exceptional mechanical properties. In this study, we investigated the mechanical performance and assembly processes of glue-coated spider silk nano-fibers into web anchors. Our goal was to identify the specific features of web anchor architecture that contribute to its mechanical strength, and to understand how these structures changed through evolution. To do this, we compared the mechanical behaviour of web anchors in an orb weaver, a hunting spider, and two basal sheet web builders using empirical and numerical tests. Our results show that orb weavers have outstanding mechanical robustness in their web anchors while using minimal material. We found

that this is achieved through the indirect attachment of the silk line to the substrate through a soft, loose region of the anchorage, known as a "bridge." This attachment mechanism results from the specific shape and movement of the orb weaver spinneret. Our findings have important implications for the understanding of the evolution of spider webs and for the development of new high-performance materials with biomedical applications.

A12.31 ADAPTATIONS TO STRESS MITIGATION IN WASP OVIPOSITORS

Wednesday 5 July 2023 15:00

Sander W.S. Gussekloo (Wageningen University, Netherlands), Robin Heinen (Terrestrial Ecology Research Group TUM School of Life Sciences Technische Universität München, Germany), Uroš Cerkvenik (Institute of Cell Biology Faculty of Medicine University of Ljubljana, Slovenia)

sander.gussekloo@wur.nl

A major contribution to the successful life history of parasitic wasps is their ability to lay their eggs inside or on larvae of other arthropods that are often concealed inside fruits, stems or wood. For egg deposition wasps use an ovipositor that consists of three elements, or valves. Two ventral valves are linked over their full length to a single dorsal valve by a tongue-and-groove mechanism that allows for sliding of the valves along each other. Our previous studies have shown that alternating movement of the valves is used to probe into substrates, which limits the required push force and risk of damage to the ovipositor. However, probing in hard substrates such as wood will result in higher stresses on the ovipositor than do softer substrates. We investigated how ovipositors are adapted to mitigate these stresses due to probing. We obtained ovipositor cross-sections of over a 100 parasitic wasp species (Hymenoptera: Ichneumonoidea) from literature and classified their substrate preference from soft to hard. From these we determined morphometric parameters relevant for stress mitigation and stiffness. Strong morphological difference were found in the tongue-and-groove mechanism linking the ovipositor valves. Sturdier connections for hard substrates suggest that probing results in high stresses on the valve connections. Coordinated movement of the valves is essential for ovipositor insertion which requires a failsafe tongue-and-groove mechanism. Understanding stress mitigation contributes to the design of ovipositor-inspired minimally invasive steerable needles for medical applications that are currently in development.

A12.32 AN EXPLORATION OF MAMMALIAN SPINES AND QUILLS

Wednesday 5 July 2023 15:00

Sam A Maguire (University of Sheffield, United Kingdom), Chris A Holland (University of Sheffield, United Kingdom)

smaguire2@sheffield.ac.uk

Biological materials are of interest due to a unique combination of inherent sustainability and excellent mechanical properties. Spines and quills have convergently evolved to look similar and have the same primary function of defence against predation, but have evolved a fascinating range of diverse secondary functions. These hierarchical

keratinous structures range from the hedgehogs shock absorbing spines, with well longitudinal stringers and transverse plates, to the North American porcupine quill’s barbed tip which makes it difficult to remove after puncture. This study seeks to determine the biological, chemical and mechanical diversity of spines and quills from the Porcupines H. africaeaustralis, E. dorsatum, H. cristata, H. brachyura, the Hedgehgos E. europaeus, A. albiventris alongside the unusual outgroup of the Echidna T. aculatus. Here we show FTIR spectra for each section of these structures as well as their morphologies and puncture performance. The Echidna’s thick and hard cuticle has not been reported and thus the implication of its use as an armoured protective layer as well as the pointed protection offered by the points is proposed. We explore the potential uses of the ridges found in some porcupines as stress concentrations to facilitate puncture as well as preferentially reinforce and force buckling in a specific direction during failure akin to the central ridge of a medieval sword. Combined this information will serve as the fundamental basis for further studies which seek to gain inspiration from natural structures and assist in future biomimetic engineering endeavours.

A12.33 COMPARATIVE ANALYSIS OF OSTEODERMS ACROSS THE LIZARD BODY

Wednesday 5 July 2023 15:30

Anastasiia Maliuk (Anastasiia Maliuk, United Kingdom), Arsalan Marghoub (University college London, United Kingdom), Edward Stanley (Florida Museum of Natural History, United States), Matthew Vickaryous (University of Guelph, Canada), Anthony Herrel (Muséum National d'Histoire Naturelle, France), Susan E. Evans (University college London, United Kingdom), Mehran Moazen (University college London, United Kingdom)

a.maljuk@gmail.com

Osteoderms (OD) are bony plates embedded within the skin, particularly common in reptiles. They are generally thought to form a protective layer between the soft tissues of the animal and potential external threats, although other functions have been proposed. The aim of this study was to characterise OD variation across the lizard body.

Representatives of three lizard species were chosen for this study. After whole body CT scanning of each lizard, single ODs were extracted from 10 different body regions, CT scanned, and characterised using nanoindentation.

Morphological analysis revealed considerable diversity in the shape and size of ODs across the species investigated. The scincidTiliqua gigaswas the only species in this study in which ODs had a similar external morphology across the head and body. All osteoderms are compound and overlapping. The external surface of dorsal osteoderms bears vermiculate ornamentation consisting of large numbers of pits and grooves. A more significant level of osteoderm diversity was found in the gerrhosauridBroadleysaurus majorand the scincidTribolonotus novaguineae. Across the body ODs vary from single non-overlapping elements to compound overlapping plates depending on their location. Enamel-like capping tissue, like that reported forHeloderma, was found only in one of the three species (B. major) examined.

Osteoderm structure is surprisingly complex and variable, both among closely related taxa, and across the body of individual animals. This raises many questions about OD function but also about the genetic and developmental factors controlling OD shape This work was supported by the HFSP (RGP0039/2019).

A12.34 CUTTLEFISH-INSPIRED BIOMIMETIC SUCTION CUPS ARE REVERSIBLE, STRONG, AND FLEXIBLE

Wednesday 5 July 2023 15:45

Brett Klaassen van Oorschot (Wageningen University Research, Netherlands), Gerline Van Beusekom (Wageningen University Research, Netherlands), Guillermo J. Amador (Wageningen University Research, Netherlands)

brett.kvo@wur.nl

Cuttlefish suction cups contain a hardened proteinaceous ring. The function of this ring is unknown. In more derived squid species, these rings may even form hook-like morphologies. Octopus species, however, are missing these rings entirely. What is the role of this sucker ring? We hypothesized that in common cuttlefish (Sepia officinalis) this ring provides structural support to resist collapse under the low pressures exerted during suction. Alternatively, the ring may provide a sealing surface in concert with papillae that grow from the ring’s edge. Here we examine the role of this ring by measuring adhesion force and pressure during suction before and after excising the ring, and again after replacing it in dissected suction cups. We then tested the ring’s function using a biomimetic model. Our findings demonstrate that sucker rings resist collapse of the suction cup rim and dramatically improve attachment. Moreover, we present a novel biomimetic suction cup that is reversible, strong, and capable of adhering to a variety of surfaces.

A12.35 A STICKY

SITUATION:

THE

CONTRADICTORY MATERIAL PROPERTIES OF GASTROPOD MUCUS

Wednesday 5 July 2023 16:00

Lauren Eggleton (University of Sheffield, United Kingdom), Chris Holland (University of Sheffield, United Kingdom)

leggleton1@sheffield.ac.uk

Gastropod mucus embodies two contradictory properties, adhesion and locomotion, which can be employed by the animal whenever the functional need arises, however, the mechanisms behind this transition are yet to be elucidated. Moreover, this material is often studied in isolation from the animal, where biological function can only be extrapolated from research undertaken in a purely engineering context. This lack of appropriate knowledge of mucus structure and function hinders its impact across a range of academic and applied fields, including soft robotics and medical adhesives.

In the search to understand the unusual flow properties of this material, the creation of a gastropod locomotion translation device demonstrates how a more holistic approach to analysing natural materials can reveal more about their true nature. Through inciting a need for a gastropod to adhere to a surface, a biocrystallisation effect was observed in the mucus and could be linked to gastropod behaviour.

Such crystallisation, when viewed within a biological context, may indicate the presence of a previously unidentified intermediate stage between locomotive and adhesive functionality. We propose this mechanism is activated and moderated using metal ions to rapidly alter the viscoelastic properties of mucus and explored this in real time using rheology, microscopy and optical profilometry. Results revealed

an unexpected relationship between the adhesive properties of mucus and ion valence, which may help explain the opposing properties of gastropod mucus and unlock its potential as a high-performance sustainable material.

-45°

A12.36 BIOMECHANICAL ADAPTATIONS AND ONTOGENETIC CHANGES IN STARFISH OSSICLES

Wednesday 5 July 2023 16:15

Raman . (Biomimetics-Innovation-Centre Hochschule Bremen – City University of Applied Sciences Bremen, Germany), Susanna Labisch (Biomimetics-Innovation-Centre Hochschule Bremen – City University of Applied Sciences

Bremen, Germany), Jan-Henning Dirks (BiomimeticsInnovation-Centre Hochschule Bremen – City University of Applied Sciences Bremen, Germany)

raman.raman@hs-bremen.de

Starfish possess a unique and complex endoskeleton which allows them to remain in the same body-posture for a prolonged period of time whilst using only very little energy. This endoskeleton is formed by many intricate bone-like structures (ossicles) embedded in a collagenous matrix. Neuronal control of the matrix fibres allows the starfish to selectively control the stiffness of the arms and the body. To actively move the arms, different types of highly specialized ossicles are each attached to several groups of small muscle fibres. Selective contraction of these muscles fibres leads to a controlled deformation of the ossicle network with multiple degrees of freedom. Interestingly, the ultrastructure of these ossicles shows the presence of a porous microstructure (stereom), similar to the structure found in cancellous vertebrate bones. Not only the stereom does vary among different ossicles types but also within the same ossicle. To investigate whether the morphology of stereom is just random or is correlated with the biomechanical stresses, a principle also often found in vertebrate endoskeletons, we performed high resolution X-Ray microCT scans of the ossicles of starfishAsterias rubens. Our results show that within each ossicle the stereom can form several characteristic patterns. We will discuss the distribution of the porosity within representative ossicles and across ossicles of different ontogenetic stages. The porosity distribution was also compared with a finite element study to analyze and discuss possible correlations of material distribution and biomechanical stresses.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A12.37 COMPARISON OF MANUAL VS. MACHINE LEARNING-BASED MOTION TRACKING FOR GAIT ANALYSIS IN CANIDS

Wednesday 5 July 2023 POSTER SESSION

Harry Gill (Manchester Metropolitan University, United Kingdom), Charlotte Brassey (Manchester Metropolitan University, United Kingdom), Robyn Grant (Manchester Metropolitan University, United Kingdom), James Gardiner (Manchester Metropolitan University, United Kingdom), Karl Bates (University of Liverpool, United Kingdom)

22562290@stu.mmu.ac.uk

Domestic dogs (Canis lupis familiaris) are a well-studied group within the field of animal biomechanics, particularly with respect to their gait. Kinematic gait analysis typically relies on infrared motion capture (mo-cap) cameras and reflective surface markers placed on specific anatomical landmarks, and is mostly applicable to domestic animals in laboratory settings.Markerless AI-based motion capture is an emerging field and may overcome several of the challenges faced by traditional mo-cap, operating beyond standard lab conditions and without the need for marker attachment. The purpose of this study is to validate the machine learning tool DeepLabCut (DLC) for analysing canid gait by comparing its output to results collected from a manual tracking software (Tracker). Eight breeds of domestic dog of varying body plans are recorded using an ‘off-the-shelf’ camera, capturing steady-state movement at 120 fps in the sagittal plane. We use DLC’s pretrained ‘SuperAnimal-quadruped’ network, trained on >40k landmarked images of mammalian quadrupeds. Several kinematic variables, such as stride lengths and frequency, are extracted to assess the agreement between the manual vs. AI-based techniques. We hypothesise that DLC will perform comparably against manual tracking across the suite of domestic dog breeds studied, given the morphological diversity of mammalian quadrupeds incorporated into the network’s training dataset. Future research will extend to other captive canids as a means of quantifying gait and monitoring welfare in zoo species.

A12.38 INTERMITTENT SWIMMING KINEMATICS OF BLUEGILL SUNFISH (LEPOMIS MACROCHIRUS): ENERGETICS VERSUS MANEUVERABILITY

Wednesday 5 July 2023

POSTER SESSION

Catherine Morris (University of Montana Western, United States), David Coughlin (Widener University, United States), Annika Pfister (Wellesley College, United States), Zoe Reynolds (Wellesley College, United States), David Ellerby (Wellesley College, United States), Bradley M Wood (University of Montana Western, United States)

catherine.morris@umwestern.edu

Locomotion is an important behavior in the life history of animals and is characterized by discrete gaits, which may be adopted for optimal energetic efficiency, fatigue resistance, or maneuverability. We evaluated the kinematics and electromyography of Bluegill Sunfish (Lepomis macrochirus) swimming at different gaits to determine the factors that might influence gait choice. In the swim tunnel, bluegill adopted a steady swimming gait at speeds below 2.0 BL/s. When swimming volitionally, either in a laboratory pool or the field, bluegill adopted an intermittent swimming gait (burst phase followed by a glide phase) and swam at average speeds of 1.0 to 1.3 BL/s. No statistical relationship was found between the kinematics of the burst and glide phases in either the lab or the field, so the phases were considered uncoupled. Furthermore, since the kinematics (tailbeat frequency, glide-duty factor) of lab and field volitional swimming

were statistically identical, the EMGs of volitional swimming in the lab likely reflect field effort. When relativized to volitional swimming speeds, the EMG intensities for both gaits were statistically identical. These results suggest that intermittent swimming may not reflect a strategy for energetic efficiency. Instead, the decoupling between the burst and glide phase may improve maneuverability, since 75% of 3D tracked intermittent swimming bouts (n=129) in the field involved a directional change. Although previous research suggests that intermittent swimming promotes fatigue resistance, we hypothesize that intermittent swimming evolved in bluegill as an adaptive gait for navigating their densely vegetated habitats.

A12.39 EXPERIMENTALLY TESTING THE LINK BETWEEN SHAPE, SIZE, AND PUNCTURE ABILITY IN THE BEAK OF CEPHALOPODS

Wednesday 5 July 2023 POSTER SESSION

Louise Souquet (Department of Mechanical Engineering University College London, United Kingdom), Simeng Wang (Department of Mechanical Engineering University College London, United Kingdom), Isabelle Rouget (Centre de Recherche en Paléontologie-Paris (CR2P) Muséum national d’Histoire naturelle SUCNRS, France), Anthony Herrel (Département AVIV UMR CNRS 7179 MECADEV CNRSMNHN, France), Susan Evans (Centre for Integrative Anatomy Department of Cell and Developmental Biology UCL, United Kingdom), Mehran Moazen (Department of Mechanical Engineering University College London, United Kingdom)

l.souquet@ucl.ac.uk

Cephalopod is a class of marine molluscs including octopuses, squid, and cuttlefish. Carnivorous predators, they feed using a chitinous beak, which they use to puncture and tear apart their prey. Octopus species feed usually on hard preys including crustaceans and molluscs, while squids and cuttlefishes mostly feed on fishes. The size and shape of the beak can vary widely between species. If these beaks were historically used for taxonomy, a recent study shows that their morphology is not only driven by phylogeny, but also carries an ecological signal. Beaks constitute efficient and powerful tools that could reflect adaptation to specialized diets. Here, we investigate experimentally the link between the shape and size of the beak and its biting abilities using puncture analysis. We used 3D printing rostrums,i.e. the biting tip of the beak, to puncture targeted materials while recording force and displacement. We tested the impact of shape using rostrum from real beaks 3D models, and a set of hypothetical CAD designed rostrum to isolate the effect of size. Our first findings show that short and blunt rostrums found in octopus species require more force to puncture the target material than long and sharp ones usually found in squids and cuttlefishes. On the other hand, for a given shape, small size requires less force to puncture the target material. This suggests that small species and juveniles may have a mechanical advantage given by their small beak size, requiring less force to puncture through hard preys.

A12.40 A PLANAR OMNIDIRECTIONAL TREADMILL TO STUDY INSECT LOCOMOTION

Wednesday 5 July 2023 POSTER SESSION

Hendrik K Beck (Imperial College London, United Kingdom), Fabian Plum (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

hb1220@ic.ac.uk

Insects seem to move effortlessly in a variety of habitats. They can walk upright, climb up vertical walls, stick to inverted surfaces, and are robust to the loss of one or even multiple limbs. Studying these fascinating locomotor skills has been a long-standing source of inspiration for six-legged walking robots. However, obtaining 3D kinematics data of insects remains difficult and at best tedious - insects generally do not cooperate. Previous work utilized spherical treadmills that were either passively or actively actuated to tackle these issues. However, passive actuation requires to tether insects, and active actuation still relies on either large spheres or involves a restricted recording area, requiring rapid feedback loops that may perturb natural locomotion.

To circumvent these limitations, we developed a planar omnidirectional treadmill, which perpetually keeps walking insects in a central region of interest. In brief, a set of small treadmills is mounted on a large treadmill; the small treadmills and the large treadmill move in perpendicular directions, and are actuated by independent motors; the insect’s position on the treadmill is tracked in real-time, and serves as the control input.

The treadmill design allows observation of natural locomotion on a flat surface; insects can freely select speed and walking direction over long periods of continuous gait cycles. By deploying our treadmill to study the 3D kinematics of insect locomotion, we hope to provide a better understanding of how six-legged walking systems, insect and hexapod robots, adapt to different mechanical scenarios.

A12.41 THERMAL ACCLIMATION STUDIES IN BROOK TROUT: CAN THEY PREDICT THE FATE OF NATIVE FISH?

Wednesday 5 July 2023

POSTER SESSION

David J Coughlin (Widener University, United States), Evelyn M Peyton (Widener University, United States), Jalen S Wright (Widener University, United States)

djcoughlin@widener.edu

As climate change alters the thermal environment of the planet, interest has grown in how animals may mitigate the impact of a changing environment on physiological function. We have been examining how thermal acclimation alters swimming performance, muscle contraction kinetics and the gene expression and protein content of myotomal muscle in cold-water fishes. Thermal acclimation to a warm environment may, for instance, blunt the impact of a warming environment on metabolism by allowing a fish to shift to slower isoforms of metabolically significant proteins such as myosin heavy chain. Our recent studies of hatchery brook trout (Salvelinus fontinalis) reveal a robust thermal acclimation response. These fish show significant shifts in swimming performance, muscle contractile properties and gene expression with changes in environmental temperature in the laboratory setting. More recently we are testing the prediction that native, wild

brook trout will show similar thermal acclimation responses. Brook trout across their range are composed many independent populations with limited gene flow between populations from different drainages. These populations are highly variable in body form and size. Our first results indicate that wild brook trout do acclimate to changes in water temperature throughout the year, with colder temperatures leading to faster swimming performance, faster muscle contraction kinetics and shifts in gene expression that mirror those of hatchery fish. For the first population of this study, an acclimation responbse supports survival in response to an increase in environmental temperature over the coming decades.

A12.42 HOW AND WHY FISHES WALK: A BIOMECHANICS PERSPECTIVE

Wednesday 5 July 2023 POSTER SESSION

Fidji Berio (Stockholm University, Sweden), Valentina Di Santo (Stockholm University, Sweden)

fidji.berio@zoologi.su.se

Fishes exhibit an extraordinary array of locomotor behaviours, from swimming with their pectoral fins, to body undulations, to leaping outside the water and walking on the substratum. Different fishes can both walk and swim underwater. Fishes that evolved walking might benefit from energy saving at low speeds by avoiding lift-induced drag and allowing adherence to the substratum in turbulent conditions. These fishes may display varying preferences for walking and swimming which correlate to the shape and size of propulsors and locomotor behaviour. In fact, walking evolved in highly different fish taxa and involves an unexplored diversity of anatomy and morphology of fins, and movements. In this project, we aim at quantifying the diversity of walking behaviour. We investigate the kinematics of swimming and walking in a range of bony and cartilaginous fishes to uncover a general pattern of how and why some fishes exhibit a walking behaviour. Fishes are recorded during walking and swimming across different speeds in a flow tank using two synchronized, orthogonal high-speed cameras. For each species, we extract video-based parameters of body undulations and pectoral fin movements. We further compare different metrics retrieved from movement parameters across the species of interest to uncover general patterns of how and why fishes walk underwater.

A12.43 THE IMPORTANCE OF ACTIVATION KINETICS TO THE MECHANICAL PERFORMANCE OF MUSCLE DURING THE WORK LOOP TECHNIQUE

Wednesday 5 July 2023 POSTER SESSION

Roger W. P. Kissane (University of Liverpool, United Kingdom), James P. Charles (University of Liverpool, United Kingdom), Karl T. Bates (University of Liverpool, United Kingdom), Graham N. Askew (University of Leeds, United Kingdom)

r.kissane@liverpool.ac.uk

The primary function of muscle is to generate force to produce movement. Prior to 1985, muscle mechanics were typically characterised using isometric or isotonic/isovelocity shortening protocols, none of

which is physiologically representative of how muscles typically work. The work loop technique, in which muscles are subjected to oscillating muscle length trajectories while undergoing phasic stimulation, was introduced as a more physiologically appropriate method to assessing muscle function, with the ‘gold standard’ approach involving replaying in vivo length trajectories and stimulation (based on the onset and cessation of muscle activation). However, the intensity of muscle recruitment has been neglected, rather muscles are maximally stimulated using square wave activation. The aim of this study was to investigate how variation in the intensity of stimulation affects estimates of in vivo power. We played back either a square-wave or the in vivo (measured or modelled) pattern of activation using: (1) in vivo muscle length change and activation patterns measured during mastication in the rabbit digastric muscle; and (2) length change and activation patterns for the extensor digitorum longus (EDL) and soleus muscles of the mouse estimated using a musculoskeletal model during trotting. We show that using square wave stimulation overestimates net power by 35% and positive work by 60% overestimate of positive work done in the digastric muscle and overestimates positive work of the soleus by 94% and of the EDL by 79%, compared to the in vivo recruitment pattern. These data highlight the importance of accounting for the intensity of muscle recruitment when determining in vivo muscle function.

A12.44 EFFECT OF SIZE, ROSSBY NUMBER AND ANGLE-OF-ATTACK ON BEETLE WING PERFORMANCE IN A REVOLVING WING SETUP

Wednesday 5 July 2023 POSTER SESSION

Gal Ribak (Tel Aviv University, Israel), Tanner Saussaman (Coastal Carolina University, United States), Roi Gurka (Coastal Carolina University, United States)

gribak@tauex.tau.ac.il

The mango stem borer (Batocera rufomaculata) is a large beetle with high intraspecific variance in adult body size (body mass 1-7 gr, wing length 3-5 cm) and a capacity for long dispersal flights. Flight distances and beetle size seem to be linked, with smaller individuals tending to fly larger distances than larger ones. To evaluate the relationship between beetle size and flight efficiency, we studied the wing-flow interaction in a revolving wing set-up. Our study focused on actual beetle wings removed from small and large individuals. We used different wing lengths (3.5-5.0 cm) at three angles of attack (15°, 30°,45°) revolving at the same wing tip velocity. Using force transducers and 3D-PTV (particle tracking velocimetry) we analyzed the aerodynamic performance of the wings as a function of wing size and the Rossby number. 3D-PTV enabled to characterized the fluid-wing interactions; thus, providing the underlying mechanisms governing the aerodynamic loads. The lift and drag coefficients increased with Rossby number but the lift coefficient of smaller beetle wings remained higher after Rossby number correction and had a higher lift:drag ratio. An analysis of the 3D properties in the wake of the wings revealed that the contribution of wing size to flight dynamics is modest compared to the increase in turbulent kinetic energy and Reynolds stress components associated with an increase in AoA. Ongoing analysis is focused on analyzing the efficiency of momentum transfer between wings and air in these turbulent flow conditions.

A12.45 SALVINA MOLESTA – A MODEL PLANT FOR FRICTIONAL DRAG REDUCTION IN TUBES

Wednesday 5 July 2023

POSTER SESSION

Albert J. Baars (City University of Applied Sciences Bremen, Germany), Alexander Köhnsen (City University of Applied Sciences Bremen, Germany), Niklas Kampf (-, Germany), Daniel Matz (City University of Applied Sciences Bremen, Germany), Antonia B. Kesel (City University of Applied Sciences Bremen, Germany)

albert.baars@hs-bremen.de

When submerged under water, the upper side of Salvinia molesta’s leaves keep an air layer due to an eggbeater shaped hydrophobic surface structure and hydrophilic tips. While one assumes that the water fern takes air under water to continue photosynthesis, this effect can be applied to technology to reduce frictional drag of liquids, which flow along surfaces. This follows from the lower viscosity of air in comparison to water. When applied to inner surfaces of tubes, drag reduction, energy demand of pumps, and possibly CO2 emissions can be reduced. The drag reduction strongly depends on the size and the geometry of the surface structure and has to be adapted to the flow. In this contribution the drag reduction of pillar and different long hole shaped surface structures are compared for turbulent tube flow, a structure size in spanwise direction of L+ = 40 and a friction Reynolds number of 180 using computational fluid dynamics. The simulations reveal that a modification of pillars towards longer holes lead to a substantial increase in drag reduction. In addition, an experimental set-up in form of an open channel flow has been developed. First results confirm the effect of small structure sizes on drag reduction.

A12.46 ARE STRONG FINGERS SLOW? BIOMECHANICS OF HIGH-FREQUENCY FINGER OSCILLATIONS

Wednesday 5 July 2023

POSTER SESSION

Cas Jorissen (University of Antwerp, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium) cas.jorissen@uantwerpen.be

The vertebrate body contains a multitude of lever systems operated by antagonistic muscle pairs. Some of these lever systems are involved in tasks with conflicting mechanical demands. To better understand these demands, insight into the biomechanical basis of performance tradeoffs is needed. For example, humans use their fingers for a multitude of reasons, some require the fingers to exert high static forces (e.g. climbing) or others perform fast repetitive movements (e.g. playing piano). People excelling in one of these tasks are expect to show differences in forearm musculature at different levels, e.g. anatomy, fibre type, and/or activation patterns. In proficient climbers, the flexor muscles can be a multitude stronger than the extensor muscles, leading to a larger antagonistic force imbalance. This imbalance might influence rapid finger movement, as fully activating the flexor muscle will inevitably result in delayed finger extension while the powerful flexors are relaxing. Muscle activation levels and timings may compensate for this effect. Here, we introduce an experimental protocol to analyse finger biomechanics in this context, and present the first results. We compare index finger forces and oscillation performance in a group

containing also climbers and musicians. Measuring maximal force output of the index finger in both flexion and extension directions gives us an estimation of the force imbalance. High-speed videos of standardised index finger oscillations quantifies maximal frequency. Surface-EMG provides comparative data on activation patterns. This experiments will give us a better insight in how high-frequency movements are constrained in multifunctional lever systems.

A12.47 WEAR RESISTANCE OF LEAF CUTTER ANT MANDIBLES

Wednesday 5 July 2023 POSTER SESSION

Dilanka Deegala (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

tim.andries@uantwerpen.be

Leaf cutter ants spend most of their adult life cutting leaves, which is metabolically expensive and mechanically demanding. To minimize the energy costs associated with leaf cutting, ant mandibles need to be sharp, which makes them susceptible to wear. Material properties play a major role in determining the wear resistance of the mandible cutting edge, and we here conducted an extensive mechanical characterization using Atta cephalotes as a model species. We measured the mechanical properties of the epicuticle of Atta cephalotes soldier mandibles at different relative humidities using a purpose-made environment control stage that can be attached to a Bruker TI 980 nanoindenter. In addition to measuring hardness and reduced modulus via indentation, nano scratch tests were used to measure the coefficient of friction, scratch hardness and wear volumes. Furthermore, dynamic mechanical analysis was used to measure time-dependent properties. Although the epicuticle hardness decreased with relative humidity, the wear volume decreased too, in direct contradiction with well-established engineering principles. An increase in loss modulus, coefficient of friction and speed dependence of wear tests with increasing humidity suggests a potential impact of time-dependent processes on wear resistance which is often neglected.

A12.48 SEED PREFERENCE RELATES TO SEED HANDLING PERFORMANCE IN A GRANIVOROUS SONGBIRD

Wednesday 5 July 2023 POSTER SESSION

Tim Andries (University of Antwerp, Belgium), Wendt Müller (University of Antwerp, Belgium), Sam Van Wassenbergh (University of Antwerp, Belgium)

kbir@aqua.dtu.dk

The dehusking of seeds by granivorous songbirds is a complex process that requires fast and strongly coordinated movements of beak and tongue. Efficient seed handling requires a degree of motoric skill and (behavioural) flexibility, since different seed types often vary greatly in size, shape and hardness. When dealing with this variability, individuals might prefer or specialise on specific seed types, which could possibly facilitate a greater seed handling efficiency of the preferred seed type, but lower efficiency for other seed types. To investigate the potential relationship between seed preference and seed handling ability, we assessed seed preferences of a large number of canaries (Serinus

canaria) through food choice experiments and related these to data of beak kinematics during feeding on small, spindle shaped canary seeds and larger, more spheroid shaped hemp seeds. We found a great variety in seed preferences among individuals: some had no clear preference for a particular seed type, while others almost exclusively fed on hemp seeds, or even prioritized novel seed types (millet seed). As expected, individuals that preferred hemp seeds were both faster and more skilled at dehusking hemp seeds, but interestingly not worse at dehusking canary seeds. In contrast, individuals that preferred millet seeds appeared to be the worst at dehusking seeds on average. This suggests that either individuals performing relatively poorly on high-caloric, tough-to-crack seeds choose to search for smaller, easier-to-crack seeds, or that persistent choice for tough seeds helps individuals to develop improved seed dehusking capacities.

A12.49 VARIATION IN HYDRODYNAMIC PERFORMANCE AMONG BOXFISH CARAPACE SHAPES

Wednesday 5 July 2023 POSTER SESSION

Merel Van Gorp (Universiteit Antwerpen, Belgium), Sam Van Wassenbergh (Universiteit Antwerpen, Belgium)

merel.vangorp@uantwerpen.be

The clade of boxfish (Ostraciidae and Aracanidae) are reef-dwelling fish that share a unique feature, the carapace. The body of Ostraciidae is completely covered by a bony shell of fused hexagonal plates. In Aracanidae, the carapace also covers the body, but is not completely closed at the caudal peduncle for some of the species. The carapace provides protection against predators, but its shape also defines their hydrodynamic characteristics. Among the many extant species, shapes vary between boxes with major lateral keels, over wedges with dorsal and ventrolateral keels, to more disc-like shapes with major dorsoventral keels. Here, we studied how hydrodynamic performance differs among twenty-four species of boxfish. Drag forces and moments were calculated using computational fluid dynamics simulations based on 3D laser-scans of museum specimens, which were all digitally rescaled to the same carapace volume. Up to 40% difference was observed between boxfish species with the lowest drag force and those with the highest drag force. We found a strong positive correlation between drag force and frontal-projected area (R²=0.91) and a negative correlation between drag force and carapace length (R²=0.68). The strong variability in drag force related to the degree of axial compression of boxfish shapes, together with the relatively high coefficients of drag in boxfish in general, suggests that weak selection pressures on drag-reduction are common in this group. Comparative results on moments about the centre of volume at different angles of attack, and resistance to imposed rotations will be discussed in the context of swimming stability.

SOLUTIONS IN GREENHOUSES.

Wednesday 5 July 2023 POSTER SESSION

A12.50 STUDYING AUDITORY-INDUCED ESCAPE MANOEUVRES AND FLIGHT ACTIVITY OF PEST MOTHS TO CREATE NOVEL BIO-INSPIRED PEST-CONTROL

dayo.jansen@wur.nl

Although greenhouses are more advanced and have greater crop yields than ever before, moths still cause considerable damage to crops. The primary method for fighting moth infestations are insecticides. This practice is under societal pressure, and so new sustainable moth control methods are needed. In nature, moths are hunted by bats, which they have developed dedicated escape strategies against. This includes an auditory system tuned to ultrasound echolocation calls, and dedicated evasive flight manoeuvres. In response, bats alter their calls and use their own specialized flight manoeuvres to counter the moth’s last_ minute effort at survival. Here, we aim to develop bio-inspired moth control solutions in a greenhouse environment. Firstly, we developed ultrasound speakers that produce bat-like sounds to deter and disrupt the natural behaviour of moths flying in a greenhouse. Secondly, we developed bat-inspired autonomous quat-copter robots that hunt down moths and eliminate them in their propellors. To quantify the efficacy of our systems, we track and analyse: 1) the escape manoeuvres of individual moths in response to ultra-sound and 2) the resulting flight activity of the moth population in greenhouses with and without our systems. When faced with our systems, moth reduce their flight by up to 85%. Moths that still do fly are found to fly more erratically and perform more escape flight manoeuvres. This research highlights the inherent predator avoidance behaviour of moths and enforces application of our new bio-inspired solution

A12.51 EFFECTS OF HEAT STRESS ON THE SKELETAL MUSCLE OF ANTARCTIC TREMATOMUS BERNACCHII AND CHIONODRACO HAMATUS

Wednesday 5 July 2023

POSTER SESSION

Mariacristina Filice (University of Calabria, Italy), Daniela Amelio (University of Calabria, Italy), Filippo Garofalo (University of Calabria, Italy)

mariacristina.filice@unical.it

Antarctic fishes are extreme stenotherm animals, adapted to live at temperatures close to the freezing point of ocean water (−1.9 °C). They experience stable annual temperature fluctuations less than 1 °C. Due to climate changes and the consequent increment in water temperature, Antarctic species are exposed to stressful conditions. The effects of increasing ocean water temperature on morpho-functional traits of Antarctic marine species is under attention. In this study we evaluated the effects of acute heat stress on the skeletal muscle of both the Antarctic haemoglobinless Chionodraco hamatus and the red blooded Trematomus bernacchii at morphological and molecular level (cell death, heat shock response, antioxidant defense and NOS/ NO system). Our preliminary results suggest a specie-specific morphofunctional response of the skeletal muscle of the two Antarctic teleosts to heat stress.

A12.52 DOES ROUTE SELECTION WHEN WALKING OVER MULTIPLE OBSTACLES MINIMISE ENERGY USE?

Wednesday 5 July 2023 POSTER SESSION

Yansangni Luo (University of Bristol, United Kingdom), J F Burn (University of Bristol, United Kingdom)

sunnyluo1202@gmail.com

Recent studies suggest that the well-established principle of minimising energy use during regular gait is also an important factor in determining how people walk across isolated obstacles. Here we asked whether, when two obstacles are present in succession, people optimise the crossing of each obstacle individually or optimise the combined crossing of both obstacles.

Two identical obstacles in the form of areas of ground to step over were marked out using two cardboard strips placed successively along a 2 m wide flat level track. The width of the strips was tapered linearly from left to right such that the narrow end could be crossed using normal step length, whilst crossing away from the narrow end required an increasingly longer, more energetically costly step. The obstacles were presented with the same and opposite orientations, and with separations of 1.6 m and 3.5 m. For each configuration, the freely-chosen paths of eight participants walking along the track were recorded using optical motion capture.

The route taken across the first obstacle was altered by both reversing the orientation of the second obstacle and by changing the separation; hence, we concluded that the route over each obstacle was not optimised independently. Regardless of orientation or separation, the routes taken across the obstacles were consistent with minimising the energy used for crossing them in combination. We conclude that the freely-chosen route over multiple obstacles cannot safely be implied from studies of walking over isolated obstacles, but is indicated by the least overall energetic cost.

A12.53 THE SKIN OF LUNGFISH PROTOPTERUS DOLLOI UNDER FRESHWATER AND AESTIVATING CONDITIONS

Wednesday 5 July 2023 POSTER SESSION

Mariacristina Filice (University of Calabria, Italy), Daniela Amelio (University of Calabria, Italy), Filippo Garofalo (University of Calabria, Italy)

mariacristina.filice@unical.it

The African dipnoi Protopterus dolloi is an obligate air-breathing fish that, during dry season, experience a period of dormancy named aestivation. Aestivation is characterized by complete reliance on pulmonary breathing, decrease of metabolism and down-regulation of respiratory and cardiovascular functions. To date, little is known about morpho-functional rearrangements induced by aestivation in the skin of African lungfishes. Our study aims to identify, in the skin of P. dolloi, structural changes and stress-induced molecules in response to short-term (6 days) and long-term (40 days) aestivation. Light microscopy showed that short-term aestivation induces a narrowing of epidermal layers and a decrease of mucous cells while prolonged aestivation is characterized by regenerative processes and

Dayo L. Jansen (Wageningen University, Netherlands), Martin J.M. Lankheet (Wageningen University, Netherlands), Henjo J. De Knegt (Wageningen University, Netherlands), Florian T. Muijres (Wageningen University, Netherlands)

re-thickening of epidermal layers. Immunofluorescence reveals that aestivation correlates with an increased oxidative stress and changes of Heat Shock Proteins expression, suggesting a protective role for these chaperons. Our findings revealed that lungfish skin undergoes remarkable morphological and molecular readjustments in response to stressful conditions associated with aestivation.

A12.54 MAGNETIC RESONANCE IMAGING (MRI) AS A TOOL FOR VISUALIZING THE 3D ARCHITECTURE OF FISH BODY MUSCLES

Wednesday 5 July 2023

POSTER SESSION

Ariel L Camp (University of Liverpool, United Kingdom), Nathan Jeffery (University of Liverpool, United Kingdom) ariel.camp@liverpool.ac.uk

The three-dimensional (3D) arrangement of fibres and connective tissues within vertebrate muscle impacts its mechanical output. Understanding this architecture-function relationship is a crucial but challenging question in biomechanics, particularly for the dorsal body (epaxial) muscles of fish. Their complex architecture--nearlyhelical swirls of fibres separated by convoluted connective tissue sheets (myospeta)--is hypothesized to have complex gearing and/ or stabilisation functions. But this complexity has made it difficult to visualize their 3D architecture. Methods like micro-dissection and serial histology provide valuable insights but are destructive and often limited to small specimens or regions. We demonstrate the use of magnetic resonance imaging (MRI) to measure 3D epaxial architecture in fish. We applied existing MRI methods for post-mortem scans with gadolinium staining to increase tissue contrast to two morphologically and phylogenetically distinct fish: rainbow trout (Oncorhyncus mykiss) and frogfish (Antennariussp.). Scans were manually segmented to reconstruct the myosepta and muscle segments, relative to the craniovertebral skeleton. Epaxial architecture was successfully visualized in both species, revealing dramatic differences in myosepta shape: nearly planar in frogfish but w-shaped in trout. MRI offered the benefits of imaging intact and relatively large (>350g) specimens across all or most of the body, although it is limited by the time, cost, and equipment availability of scanning. MRI segmentation was time-consuming, but will hopefully benefit from improved tools for automated segmentation. Overall, MRI offers a promising tool for understanding the structure and ultimately diversity, evolution, and function, of the fascinating muscle architecture of fish bodies.

A12.55 UNDERSTANDING THE FUNCTIONAL MORPHOLOGY OF CUTTLEFISH SUCTION CUP RINGS

Wednesday 5 July 2023 POSTER SESSION

Gerline J Van Beusekom (Wageningen University Research, Netherlands), Brett Klaassen van Oorschot (Wageningen University Research, Netherlands), Guillermo Amador (Wageningen University Research, Netherlands)

gerline.vanbeusekom@wur.nl

Keywords: sucker ring, Sepia officinalis, biomimetic, suction force, cephalopods. Cuttlefish possess arrays of suction cups throughout their arms and tentacles. Each suction cup has a stiff ring lining the inside of its cavity; however, its function is poorly understood. Here, we describe the functional role of the stiff sucker ring in the suction cups of cuttlefish. We hypothesize that the stiff sucker ring prevents the collapse and failure of the suction cup during attachment. We tested this hypothesis by attaching Sepia officinalis suction cups to a glass substrate and measuring the suction force generated. We first tested the cups with their rings in place, then removed the ring and tested again, and, finally, tested once more after reinserting the ring into the cup. We found that removal of the sucker ring reduced suction force to nearly zero, and that placing the ring back restored the suction cup’s suction force. Therefore, our observations demonstrate that a stiff sucker ring improves the suction force by reinforcing the suction cup and delaying failure. This work could serve as motivation for developing biomimetic, passive suction cups.

A12.56 MECHANISMS IN CHINOOK FRY AND PARR

Wednesday 5 July 2023 POSTER SESSION

Moritz Haustein (Institute of Zoology University of Cologne, Germany), Ansgar Büschges (Institute of Zoology University of Cologne, Germany), Till Bockemühl (Institute of Zoology University of Cologne, Germa moritz.haustein@uni-koeln.de

Walking is a major locomotive strategy of animals to move on land. Although Drosophila melanogaster represents an expedient model organism for studying walking, its tiny size and ability for rapid leg movements have so far hindered detailed analysis of stepping kinematics. To overcome this hurdle, we established a 3D motion capture system and fitted a kinematic leg model to the tracked leg parts. For this, flies walked on a spherical treadmill and leg movements were recorded with six high-speed cameras. Positions of leg and body keypoints were automatically tracked in video frames using the DeepLabCut toolbox and triangulated to obtain 3D reconstructions. Afterwards, we created kinematic chains for all legs based on microcomputed tomography data. To determine joint angles, forward kinematics of these chains were optimised using a gradient descent algorithm that minimised the distances between the positions of the tracked and model leg keypoints. Each pair of legs showed distinct joint kinematics during forward walking. Testing of different configurations of degrees of freedom (DOF), i.e. independent rotational axes, for the model joints revealed that the thorax-coxa joint has three DOFs and that an additional roll-DOF was required for fitting the movements of the front legs, but not necessarily for the other leg pairs. Additionally, rotations of the femur-tibia plane in the middle legs emerged from interactions between two joint DOFs. In conclusion, when combined with the ever-expanding genetic toolbox offered by Drosophila, the experimental platform presented here can facilitate investigations of Drosophila walking behaviour in the future.

A12.57 ZEBRA FINCH SYRINGEAL MUSCLES EXHIBIT SUPERFAST SHORTENING

Wednesday 5 July 2023

POSTER SESSION

(University of Southern Denmark, Denmark)

nwg@sdu.dk

Birdsong plays a key role in avian behaviour, enabling birds to perform rapid acoustic modulations, facilitated through the action of the syrinx. The songbird syrinx is specialised for this function, where musculature is composed of primarily superfast fibres. Enabling muscle to operate at frequencies of up to 200 Hz – among the fastest operational frequencies noted to date. However, characterisation of muscle function is missing one key part of the puzzle: the non-isometric force-velocity relationship. Here we investigated the non-isometric properties of this muscle type using the syringeal muscle of zebra finches. We determined force-length and force-velocity, as well as assessing the impact of temperature, and animal sex upon these properties. The shortening velocity of zebra finch syringeal muscle was estimated to be up to 46 L0 s-1, this puts syringeal muscle among some of the fastest muscle types, matching the shortening speed seen in the ultrafast myotomal muscle of zebrafish (45 L0 s-1). Despite previously noted male-female differences in twitch dynamics, no significant male-female differences in shortening velocity were found. This finding is consistent with previous results in other muscles, where twitch dynamics are more closely aligned to cyclic performance than force-velocity parameters. Q10 values highlight syringeal and other superfast muscles show a high degree of temperature dependence, within most endotherms this is unlikely to be of importance, though some groups which use superfast muscles may be negatively impacted.

A12.58 A NOVEL FUNCTION FOR THE CUTICLE IN EXPLOSIVE SEED LAUNCH?

Thursday 6 July 2023 09:00

Erin Cullen (Max Planck Institute for Plant Breeding Research, Germany), Ulla Neumann (Max Planck Institute for Plant Breeding Research, Germany), Angela Hay (Max Planck Institute for Plant Breeding Research, Germany)

ecullen@mpipz.mpg.de

Plants have evolved a myriad of different strategies to disperse their seeds. For example, dandelion seeds are carried by the wind, or in the case of Cardamine hirsuta, the plant utilises exploding seed pods to disperse its seeds. Previous work found that a mechanical instability in the fruit was responsible for generating the energy needed for explosive dispersal. However, the mechanism for seed launch is unknown. In this work we identified a flightless (fli) mutant, where the fruit explodes,

but seed launch often fails. We show through complementation analysis that ABCG32, a plasma-membrane bound transporter that transports hydrophobic cutin monomers, underlies the fli phenotype. fli exhibits a defective cuticle phenotype in both the seed and the side of the valve in contact with the seed. By TEM, we observed perforations in the seed coat cuticle. We propose this may be the reason why seed launch fails in the fli mutant. Alternatively, cuticle formation may be required for successful abscission between the seed and the attaching funiculus. Transcriptional reporters show that FLI/ABCG32 is expressed in the epidermis of aerial organs, including the valve, seed and funiculus of C. hirsuta fruit. RNAseq analysis indicates that cutin and wax biosynthesis pathways are perturbed in these tissues in the fli mutant, possibly to compensate for loss of cutin monomer transport. We are currently investigating how the chemical composition of the cuticle may differ in fli compared to wild type. Overall, our work may suggest a novel function for the cuticle in explosive seed launch.

A12.59 HUNTING CYCLE IN THE VENUS FLYTRAP (DIONAEA MUSCIPULA): BIOMECHANICS OF TRAP REOPENING AND DIGESTIVE CAVITY FORMATION

Thursday 6 July 2023 09:00

Grażyna M Durak (University of Freiburg, Germany), Rebecca Thierer (University of Stuttgart, Germany), Renate Sachse (Technical University of Munich, Germany), Manfred Bischoff (University of Stuttgart, Germany), Thomas Speck (University of Freiburg, Germany), Simon Poppinga (Technical University of Darmstadt, Germany)

grazyna.durak@livmats.uni-freiburg.de

A notorious carnivore – the Venus flytrap (Dionaea muscipula) –produces remarkable shape-shifting leaves which are modified into snap-traps, enabling the plant to capture and digest prey. The traps are capable of executing a wide range of motion, thus allowing them to perform their unusual task. Here, we investigate trap reopening following snap-closure without providing any prey in two D. muscipula morphotypes which produce normal, N-traps, max. ≈3 cm, and large, L-traps, max. ≈4.5 cm in length. We employ 3D Digital Image Correlation (3D-DIC), time-lapse photography together with morphological and mechanical testing, showing that the trap reopening can follow several distinct scenarios: uniform, synchronous motion, asynchronous lobe movement or an initial smooth bending with a snap-through step towards the end of the reopening cycle. We conclude that the process itself depends on a combination of factors, including size, morphology (slenderness), as well as turgor and/or cell growth of individual snap-traps. We therefore revise the previous concept of trap reopening as a smooth, uniform event and report that the plants can also be affected by trap breakage, thus preventing the damaged snap-traps from further engagement in the hunting cycle. We also aim to incorporate MRI imaging as a tool to probe the physiological processes underlying trap reconfiguration and hermetic sealing of the green stomach which forms when a prey item is successfully captured. Our research provides fundamental work in functional morphology, plant biomechanics and also serves as inspiration for biomimetic design in e.g., soft robotics.

Nicholas W. Gladman (University of Southern Denmark, Denmark), Coen P. H. Elemans

A12.60 BLUE LOTUS LEAF UNFOLDING: DEVELOPMENTAL PROCESS AND RELATED CHANGES IN ANATOMY

Thursday 6 July 2023 09:30

Michelle Modert (University of Freiburg, Germany), Rahel Eckert (University of Freiburg, Germany), Tom Masselter (University of Freiburg, Germany), Thomas Speck (University of Freiburg, Germany)

michelle.modert@biologie.uni-freiburg.de

The blue lotus (Nymphaea caerulea) is well known for its appealing blue-purple blossom. Its leaf development and the related unfolding movement are, however, no less intriguing as they occur at the interface between water and air. There are rather few studies on the unfolding of different leaves, although the underlying principles are promising for bio-inspired (un)packaging systems. In the present study, three ontogenetic leaf stages of Nymphaea caerulea are defined by morphological traits and the anatomical arrangements are investigated to better understand the mechanisms responsible for unfolding.

From the rhizome, the lamina starts developing underwater with its two leaf halves furled side by side (1). Then, the leaf petiole grows and brings the leaf to the water surface where the apical tip breaks first through the water surface. Here, the folded leaf performs an elliptic movement via its petiole, probably to gain space within the sometimes dense foliage cover on the water surface (2). Then, it aligns horizontally and the leaf halves unfurl simultaneously on the water surface (3). The whole procedure takes about 3 weeks and resembles in its pattern other floating leaves.

Various changes on the cellular level potentially favour unfurling: on the ventral side, palisade cells proliferate and expand while on the dorsal side, the aerenchyma with its intercellular spaces extends. Cell proliferation and expansion in combination with unfolding are also known from other aquatic plants, e.g. Euryale ferox, as well as in leaves from land plants, e.g. Sesleria nitida, and even flowers, e.g. Ipomoea tricolor.

A12.61 CLIMBING AND SURVIVAL OF VINES AND LIANAS: ITS NOT A GAME OF PERFECT

Thursday 6 July 2023 09:45

Nicholas P Rowe (Nicholas Peter Rowe, France), Patricia Soffiatti (Department of Botany Federal University of Parana State Curitiba, Brazil), Tom Hattermann (Botany and modelling of plant architecture - CNRS, France), Patrick Heuret (Botany and modelling of plant architecture - INRAE, France)

nprowe22@gmail.com

Climbing is a risky business for biological species and technical artefacts. Vines and lianas have evolved many mechanisms to ensure that searching, spanning gaps, climbing upwards, and attaching to supports all work in the conditions for which they have evolved. Recent

observations of climbing plants in their natural environment: time lapse imaging, mechanical measurements and anatomical studies indicate that things rarely work perfectly. Strong winds, pounding by rain, slipping off supports, mechanical failure of attachments and even “decapitation” by herbivores, to list a few, are some of the perils that are ever present in natural conditions in the tropical rainforest. So, how do climbing plants avoid these difficulties and construct the biomechanically resistant and safe-looking, well-organised trellises and canopies we see in tropical forests ? We show some of the tricky and dangerous situations that climbing plants find themselves in and discuss the mechanisms that help them come out on top. It is an interesting example for studies in functional ecology and how we measure “functionality”. Things might just work half the time or half the potential or perhaps only 10 % functionality will do. If one mechanism doesn’t work well, another mechanism might be deployed meaning that functional traits can act partially together to achieve a kind of compromise functionality. This is common in climbing plants and seems to be particularly suited to highly perturbed environments. Such characteristics, both conceptual and practical, are interesting pointers for designing artefacts and soft robots adapted to explore unstructured and perturbed environments.

A12.62 FUNCTIONAL MORPHOLOGY AND BIOMECHANICS OF THE DAMAGERESISTANT INTERFACE BETWEEN THE EUROPEAN MISTLETOE AND ITS HOST

Thursday 6 July 2023 10:00

Max D Mylo (IMTEK @ University of Freiburg, Germany), Mara Hofmann (Cluster of Excellence livMatS @ University of Freiburg, Germany), Thomas Speck (Cluster of Excellence livMatS @ University of Freiburg, Germany), Olga Speck (Cluster of Excellence livMatS @ University of Freiburg, Germany)

max.mylo@livmats.uni-freiburg.de

The evergreen, hemiparasitic European mistletoe (Viscum album) is one of the most common and visually striking parasites in Europe. Once the bird-dispersed seeds have attached to a host branch, mistletoes form a so-called haustorium, which provides a physiological (water and nutrient uptake) and functional (mechanical anchorage) connection. Over the next 20 years of growth, the mistletoe reaches a diameter of more than 2 m. Despite the additional resulting loads, the connection to the host never fails. X-ray microtomographic scans of mistletoes revealed that the haustorium initially consists of several small sinkers, maximising the contact area. During the subsequent joint but also competitive growth of mistletoe and host, the individual sinkers merge into one large, wedge-shaped sinker near the attachment site. In addition, the mistletoe grows along the host branch, increasing water uptake and promoting vegetative reproduction through cortical strands. Light microscopic analyses showed a sharp separation between the two species at cellular levels and gradients of lignification and cell wall thickness from the woody host to the predominantly parenchymatous mistletoe. Tensile tests with subsequent fracture surface analysis on mistletoe-host samples revealed that the mechanical strength remains constant during growth and thus does not enter a damage-prone state. In addition, the sinkers of young mistletoes function as redundancy mechanisms, which is reflected in the pre- and post-failure events of the stress-strain curves. The aim of future work is to mechanically characterise the initial host penetration and to transfer functional principles of the damage-resistant interface to bio-inspired technical materials systems.

A12.63 GROWTH FORM BIOMECHANICS AND STRUCTURAL-MECHANICAL ADAPTABILITY IN MONOCOTYLEDONS.

Thursday 6 July 2023 10:15

Linnea Hesse (Hamburg University, Germany)

linnea.hesse@biologie.uni-freiburg.de

The loss of secondary vascular growth in plants is a very rare event which is highly correlated to the evolutionary step from a terrestrial to an aquatic habit. Monocots are one of only five angiosperm groups documented in which the vascular cambium has been lost and it is argued that they might have evolved from an aquatic dicot. Losing the vascular cambium results in morphological and histological changes that determine the atactostele arrangement of isolated, closed collateral vascular bundles which are so characteristic for monocotelydons. At some point, monocots regained a terrestrial habit that allowed the evolution of different growth forms based on a fiber-reinforced design principle (atactostele) with high structural diversity, but unable to adapt structurally through secondary thickening growth: tall palms, dragon trees, small and large grasses (e.g. e.g., bamboo), climbing species (e.g.,Monstera, rattan), and tiny floating individuals (e.g., duckweed).

The question arises whether the different growth forms share common biomechanical features and how monocotyledons can mechanically adapt to their environment despite the absence of a secondary cambium. For this, biomechanical experiments (bending and torsion) are carried out together with light microscopy, microcomputed tomography and magnetic resonance imaging to understand the biomechanical properties and structural pattering of different monocots with varying growth form.

The results will serve as input for biomimetic projects aimed at transferring the structural and adaptive principles of monocots into bioinspired, fiber-reinforced composites with responsive and tailored mechanical properties.

A12.64 NATURAL COIL SPRINGS: SPIRALIZATION AND BIOMECHANICS OF PASSION FLOWER TENDRILS

Thursday 6 July 2023 11:00

Frederike Klimm (University of Freiburg Plant Biomechanics Group GrowBot @ FMF Cluster of Excellence livMatS @ FIT, Germany), Thomas Speck (University of Freiburg Plant Biomechanics Group GrowBot @ FMF Cluster of Excellence livMatS @ FIT, Germany), Marc Thielen (University of Freiburg Plant Biomechanics Group GrowBot @ FMF FIT, Germany)

frederike.klimm@biologie.uni-freiburg.de

Instead of investing in a stiff, self-supporting stem, climbing plants rely on host structures in order to reach upwards towards the light. Passion flowers, such as Passiflora caerulea and Passiflora discophora, attach to their supports by tendrils. The tendril tips “grasp” their support (P. caerulea) or develop adhesive pads (P. discophora), which enable in the latter species secure attachment even to flat surfaces. Once attached by either means, the tendrils coil along their length axis and form a spring-like structure. Using a new custom-developed

setup we were able to measure the contractile force generated by this movement taking P. caerulea tendrils as an example. This was done for the first time continuously throughout the coiling process for a time period of several days and isolated from self-weight forces of the plant body. Simultaneous measurements of the plant's water status allowed to estimate its influence on the tensile stress in the tendril. Based on these results and on complementary anatomical and morphological investigations, we propose a two-phasic process for the spring formation, which consists of an active coiling phase, that is followed by a stabilization phase in which the tendril stiffens by increasing lignification. Extensive tensile tests on P. discophora tendrils show that in the coiled state, the tendrils function similar to a technical coil spring and provide in addition to secure attachment also high energy dissipation in the attachment system.

A12.65 PLANT ORGAN ACTUATION IS POWERED BY A MULTI-SCALE SUITE OF CELL WALL ARCHITECTURAL FEATURES

Thursday 6 July 2023 11:00

Anja Geitmann (McGill University, Canada), David Sleboda (UC Irvine, United States), Reza Sharif-Naeini (McGill University, Canada), Aravind Jayasankar (McGill University, Canada)

geitmann.aes@mcgill.ca

Pulvinus organs are joint-like motor organs that power active leaf folding in many plants. To generate a hypothesis about the underlying mechanical principles, we built a soft hydraulic actuator that mimics pulvinus structure and bending mechanics. Adding circumferential hoop reinforcements to the hydraulic “cells” made from soft silicone dramatically improved its bending performance, and we hypothesized that biological pulvinus organs may contain analogous reinforcements that guide tissue swelling during rapid turgor changes. To validate this in vivo, we used osmotic baths to swell live, isolated pulvinus organs and tissues from Mimosa pudica and screened for nonuniform changes in their 3D shape. Excised pulvinus organs displayed strongly anisotropic swelling behavior at all hierarchical scales studied, indicating that structural specializations control turgor-induced shape changes at multiple spatial scales. Specialized cell wall structure and epidermis morphologies revealed by electron microscopy support this interpretation. Our findings provide insight into the role of cell wall structure in plant motor strategies, underscore the hierarchical, emergent nature of biomechanical systems, and highlight design principles that can inform the development of biologically inspired soft actuators.

A12.66 SEASONAL VARIATIONS IN THE TOUGHNESS OF LEAVES

Thursday 6 July 2023 11:30

David Taylor (Trinity College Dublin the University of Dublin, Ireland)

dtaylor@tcd.ie

Toughness is an important property of leaves, characterizing their resistance to fracture and their ability to tolerate defects. Measurements

of fracture toughness for leaves ofGriselinia littoralistaken over a oneyear period showed variations of more than a factor of two. Toughness was higher during the winter, demonstrating typical cold acclimation behaviour. Interestingly toughness also rose somewhat during the summer, suggesting a degree of “hot acclimation”, perhaps driven by dehydration. Ambient temperature was found to be a good predictor of toughness, most accurately when functions of temperature some time before the testing date were used. This suggests that structural changes which alter toughness in these leaves take about one week to come into effect.

A12.67 SPINE AND ROOT ANCHORAGE IN A CLIMBING CACTUS: A TWO-STEP ATTACHMENT STRATEGY AND ITS RELEVANCE

FOR TECHNICAL BIO-INSPIRED DEVICES

Thursday 6 July 2023 11:45

Patricia Soffiatti (Department of Botany - Federal University of Parana State Curitiba PR (UFPR), Brazil), Nicholas P. Rowe (Botany and modelling of plant architecture - CNRS, France)

psoffiatti.ufpr@gmail.com

Climbing plants have countless strategies for anchorage and safe access to the canopy.Selenicereus setaceusis a climbing cactus from dry, lowland forests of Southern Brazil. Stems have “light” compositions, with limited stiff tissues, relying on turgescence and cross-section geometry for rigidity. It develops two types of attachment, via spines and roots in a combined “2-step” system. Spines are pre-formed on the edges of triangular stems, in groups of 3-5, pointing in different directions like grapnels. Spines are rigid with thick-walled cells guaranteeing instantaneous attachment with surrounding vegetation. Roots are formed later and emerge through the stem surface. Unlike spines their deployment is slower requiring growth and tend to only anchor to solid supports like tree trunks. To measure the strength of roots and spines, simple tensile tests were carried out in the field with a portable Instron device. One single spine can sustainca.2.6 N (corresponding to an equivalent stem length of 2.6 m and a mass of 285g. One root can withstandca.11.8 N (corresponding to a stem length of 10.5 m and mass of 1200g). This “2-step strategy” is efficient in guaranteeing anchorage in widely different environments; in moving (wind swept) shrubby habitats and in sheltered understory on massive tree trunks. Furthermore, one mechanism (spines) can facilitate the steadying or bracing of the cactus stem during the slower root growth. The mechanisms are of particular interest for the development of technologies applied to anchorage, in complex combinations of soft and hard tissues for soft-bodied artefacts.

martin.horstmann@rub.de

The freshwater crustacean Daphnia is well-known to adapt to changing predator environments by the formation of phenotypic plasticity, e.g., inducible behavioural and morphological defences. While defensive traits in many species have already been described, the actual mode of action reducing the predation rate is mostly unknown, e.g., in D. longicephala. This species is known to form a protruding head morphology projecting its back of the head to a crest-like structure in the presence of the backswimmer Notonecta. Furthermore, the larger, Notonecta-defended morph is known to swim faster. Previous studies described that defended morphs are attacked more often, but also found that they evade these attacks more efficiently. Therefore, we tried to reveal whether the turbulences elicited by the daphnids’ locomotion play a role in the detection and capture efficiency of Notonecta. We used particle image velocimetry (PIV) to visualize the flow fields around D. longicephala and the vortices left behind in the medium. That allowed to determine the volume of the medium affected by the daphnids’ locomotion. Moreover, we determined the velocity of the animals as well as of the fluid and evaluated the longevity of vortices. In addition to the analysis of swimming movements using PIV, we conducted predation experiments to verify the derived hypotheses. These experiments additionally revealed that prey handling time is extended in the defended morph. Based on these results, deeper insights are possible into how the predator-prey-interaction between D. longicephala and Notonecta is mediated by the biomechanical aspects of morphology and locomotion.

A12.69 CAPTURING THE IN VIVO KINEMATICS OF THE MUSTELID BACULUM DURING MATING USING XROMM.

Thursday 6 July 2023 12:15

Emma Clear (Manchester Metropolitan University, United Kingdom), James Gardiner (Manchester Metropolitan University, United Kingdom), Robyn A. Grant (Manchester Metropolitan University, United Kingdom), Michael Carroll (Manchester Metropolitan University, United Kingdom), Karl Bates (The University of Liverpool, United Kingdom), Charlotte A. Brassey (Manchester Metropolitan University, United Kingdom)

emma.clear@stu.mmu.ac.uk

Thursday 6 July 2023 12:00

The mechanical behaviour of an individual’s genitals directly impacts upon their fitness. In internally fertilising animals, sperm must be delivered by the male and received by the female. This is achieved by functionally mechanical reproductive structures. Investigating animal copulation has been limited due to the inherently ‘hidden’ nature of reproduction. Previous research has focused on describing male intromittent organ morphology and corresponding female parts, usually taken from cadavers, to infer function from form. Further attempts to illuminate male-female interaction has involved in copula freezing (invertebrates, small reptiles) and analysis of copulatory fit, again using cadavers (cetaceans, artiodactyl, large reptiles). However, these techniques fail to assess the live kinematics of mating. Here

Martin Horstmann (Ruhr University Bochum, Germany), Eva M. Schulenberg (Ruhr University Bochum, Germany), Linda C. Weiss (Ruhr University Bochum, Germany), Ralph Tollrian (Ruhr University Bochum, Germany)

A12.68 BIOMECHANICAL ASPECTS

OF PREDATOR-PREY-INTERACTIONS BETWEEN WATER FLEAS (DAPHNIA) AND BACKSWIMMERS (NOTONECTA)

for the first time, we image the internal kinematics of the baculum or os penis, visualised using a live biplanar x-ray imaging system and marker-less tracking of X-ray Reconstruction of Moving Morphology (XROMM) data. We do this using the domestic ferret (Mustela putorius furo), owing to their well-developed bacula, seasonal mating pattern and appropriate body size for the x-ray set-up. Data presented here indicate that the motion of the baculum tightly matches that of the male pelvis, the baculum moves at ~6Hz during periods of active thrusting and the amplitude of this movement is ~1cm relative to the female pelvis. Additionally, Fourier analysis is capable of differentiating baculum movement across multiple forms of copulatory behaviour. A better understanding of the in vivo kinematics of ferret genitalia will help address evolutionary questions regarding the biomechanical function of the carnivoran baculum.

A12.70 HOW IT WORKS: THE NEEDLEFISH’S NOSE

Thursday 6 July 2023 14:30

Jonathan P.L. Cox (University of Bath, United Kingdom), Alice C. Stein (University of Bath, United Kingdom), Grace Brison (University of Bath, United Kingdom), Matthew P. Copley (University of Bath, United Kingdom), James S. Maclaine (Natural History Museum London, United Kingdom), Graham S. Martin (TotalSim CFD Ltd, United Kingdom), Matthew Cross (TotalSim CFD Ltd, United Kingdom), Koen Van Mierlo (TotalSim CFD Ltd, United Kingdom), Heather S. Borsuk (University of Bath, United Kingdom)

j.p.l.cox@bath.ac.uk

Most people know that sharks have a fantastic sense of smell. But what about the other thirty-odd thousand species of fishes, whose noses adopt a bewildering variety of forms? Here we present work on ostensibly one of the simplest piscine noses, that of the needlefish (Belone belone), an elongated marine fish related to flying fishes. The needlefish’s nose comprises a deep open pit. Housed within this pit is a misshapen protrusion whose exact location can vary between individuals, and even between the twin nasal pits of an individual. Using a multidisciplinary approach (inspection of museum specimens, X-ray microcomputed tomography, image processing, 3D printing, dye visualisation, and computational fluid dynamics) we have demonstrated how the needlefish’s nose samples water from the external environment, and how this water is circulated over its olfactory sensory surfaces in order to capture scent. We are now beginning to quantify the number of scent molecules a needlefish can detect, so that we can compare its olfactory ability with that of other fishes, and other animals. The ultimate goal of this presentation is to show that the needlefish’s nose is anything but simple. Engineering and aeronautical terms such as vortices, Reynolds numbers, separation, boundary layers, and NACA scoops will loom large.

Josefa F Jerg (Department of Biomimetics Hochschule

Bremen – City University of Applied Sciences, Germany), Lukas Schmerling (Department of Biomimetics Hochschule Bremen – City University of Applied Sciences, Germany), Niklas Kampf (Department of Biomimetics Hochschule Bremen – City University of Applied Sciences, Germany), Tobias Kohl (Chair of Zoology Department of Zoology Technical University Munich, Germany), Harald Luksch (Chair of Zoology Department of Zoology Technical University Munich, Germany), Susanna Labisch (Department of Biomimetics Hochschule Bremen – City University of Applied Sciences, Germany), Jan-Henning Dirks (Department of Biomimetics Hochschule Bremen – City University of Applied Sciences, Germany)

felinejerg@yahoo.de

Rattlesnakes use their rattles as a warning device and can use them very persistently when needed. Therefore, it seems likely that the rattlesnake tail morphology allows for a maximum of acoustic emission with a minimum of movement.

To investigate whether the movement of the tail is effected by the number of tail segments we performed high speed videorecordings of Crotalus atrox snakes moving their tail. Computer Vision methods were used to describe the locomotion pattern of the rattle mechanism. Our first results show harmonic oscillations with dominating frequencies between 90 and 105 Hz to the lateral axis of the snakes’ body to be the dominant elements of the rattling.

CT scans were used to reconstruct the detailed morphology of the rattle-segments. The 3D-model and the locomotion pattern serve then to create a multi-body simulation.

The number of segments was adjusted to analyse the possible changes of movement. Using this results we will discuss the effects of rattlesnakes’ tail morphology and number of segments on its movement efficiency and possible effects on acoustic emission.

A12.72 NATURAL BORN SUCKERS: A COMPARATIVE STUDY OF HOW THE CIBARIAL ANATOMY OF XYLEM-FEEDING INSECTS SCALES ACROSS ONTOGENY AND BETWEEN SPECIES

Thursday 6 July 2023 15:00

Elisabeth A Bergman (University of British Columbia, Canada) elisa.a.bergman@gmail.com

Xylem-feeding insects face a unique problem: xylem sap within the vascular tissue of plants is nutrient-poor, consisting mostly of water, and is also under tension (i.e., negative pressure) that can exceed 1MPa. To extract and ingest the large quantities of this nutrient-poor liquid required to sustain their metabolism, these insects have evolved a greatly enlarged muscular cibarial pump. But how the capacity of this pump changes across the insect’s ontogeny, and how it varies between species, is unknown. Micro-CT scans of cibarial anatomy and measurements of cibarial dilator muscle (CDM) sarcomere length were collected for two species of xylem-feeding spittlebug (Philaenus spumarius, Aphrophora permutata) and a leafhopper (Graphocephala fennahi). Key morphological parameters of cibarial anatomy were measured from the micro-CT scans, including CDM volume and physiological cross-sectional area, cibarial chamber volume, and cross-

sectional area of the cibarial diaphragm. While both spittlebugs show CDM volume, cibarial chamber volume, and cibarial diaphragm area scaling close to geometric similarity, G. fennahi shows hyperallometric increases in CDM and cibarial chamber volume and diaphragm area. In contrast, sarcomere length increased in the spittlebugs, but not G. fennahi. These differences indicate that xylem-extracting cibarial pumps display different morphologies and growth profiles resulting in changes in maximum tension generating capacity between life stages. Across spittlebug ontogeny, an increasing capacity to generate negative pressures within their cibarium could indicate an increased capacity to feed on plants with greater xylem tensions, allowing adult bugs access to different host plants.

-45°

A12.73 PERCHED BIRDS DON’T GRIP THE POLE.

Thursday 6 July 2023 15:15

Anick Abourachid (Museum Nationa ld'Histoire naturelleCNRS, France), Simon Potier (MNHN, France), Idriss Pelletan (MNHN-CNRS, France)

abourach@mnhn.fr

Birds' feet have a variety of shapes, adapted to the constraints of the environment: webbed feet in swimming birds, pincer feet in perching birds, for example. These adaptations concern both the integument, with a more or less enveloping skin, and the size and orientation of the toes. The mechanics of bird foot grasping have been modelled but no experimental measurements have been made to determine the importance of foot morphology in perched balance. We mapped the pressure exerted by each toe on the feet of four species of birds perched on a horizontal, inclined or rotated perch to determine the participation of the toes in postural stability. Depending on our species, the feet had different shapes: one toe back, three toes forward in crows, toes free or combined in a skin sheath in kingfishers; two toes forward and two toes back in macaws, one toe back, two toes forward and one toe of variable orientation in buzzards and owls. The analyses show that the quiet perched birds do not grip the pole. No pressures are exerted by opposing fingers. In case of disruption, balance management is achieved by body position and wing flapping to maintain pressure on the top of the pole. The morphology of the feet is not the main determinant of perched balance

A12.74 PUSHING VERSUS PULLING: UNUSUAL DIVISION OF LABOUR BETWEEN TARSAL ATTACHMENT PADS IN BUSHCRICKETS

Thursday 6 July 2023 15:30

Jing Yi Bu (University of Cambridge, United Kingdom), Walter Federle (University of Cambridge, United Kingdom), Simon Chen (University of Cambridge, United Kingdom)

jyb21@cam.ac.uk

Insects have evolved different leg attachment devices adapted for efficient locomotion on substates of different textures and orientations. Two types of smooth attachment pad, tarsal euplantulae and pretarsal arolium, are found in insects from diverse orders such as the Blattodea, Heteroptera and Hymenoptera. These pads have been shown to serve different functions; euplantulae mainly produce friction when pushed and pressed against the substrate, whereas the arolium produces shear-sensitive adhesion that increases when pulled towards the body. Bushcrickets represent an interesting exception to this rule. They have lost their arolium but their distal euplantula is enlarged compared to the three proximal ones. Here we test the hypothesis that the large distal euplantula functions as a shear-sensitive adhesive pad that has taken over the function of the arolium, whereas the proximal euplantulae serve as friction pads used for pushing. Video recordings and microscopy of Stilpnochlora couloniana bushcrickets climbing on substrates of different orientations showed that during inverted climbing, the insects indeed mainly adhered with the large distal euplantula, whereas when walking horizontally, they used mostly the proximal euplantulae. On vertical substrates, feet above the body centre of gravity attached mostly with the distal euplantula, whereas feet below the centre of gravity used mainly the proximal euplantulae. Our findings confirm that there is a division of labour between the proximal and distal euplantulae in bushcrickets, supporting the idea that in the course of evolution, the enlarged distal euplantula has taken over the function of the previously lost arolium.

A12.75 THE DYNAMIC SURFACE OF THE SADDLE REGION IN HORSES

Thursday 6 July 2023

15:45

Jorn A Cheney (University of Southampton, United Kingdom), Michael A Frill (Royal Veterinary College, United Kingdom), Kristina P Smirnova (Royal Veterinary College, United Kingdom), Sharon E Warner (Royal Veterinary College, United Kingdom)

J.Cheney@Soton.ac.uk

Equine back pain is prevalent in at least 35% of ridden horses and often attributed to poor saddle fit. Saddles are designed and assessed with a stationary horse. However, the saddle is placed on, or adjacent to, epaxial muscles and extrinsic muscles of the forelimb which activate in temporally and spatially distinct patterns, signifying that, despite a relatively rigid skeletal frame, the overlaying soft tissue supporting the saddle is dynamic. Here our aim was to measure the regional morphing of the equine back during locomotion to understand how soft tissue movement could lead to high pressures and tissue damage. We measured shape change across the equine back in walk and trot, using photogrammetric high-speed surface reconstructions to create a map of the most and least mobile areas of the equine back for the two gaits. This map may be critical for future saddle design as the least mobile areas of the back are the most appropriate for distributing pressure and, thus, the regions best justified for supporting the compressive forces of the saddle and rider.

A12.76 CONTROL OF HIGH-SPEED JUMPS: A COMPARATIVE STUDY ON ROTATION AND ENERGETICS OF THE CRICKET (MECOPODA ELONGATA) AND LOCUST (SCHISTOCERCA GREGARIA)

Thursday 6 July 2023 16:30

Chloe K Goode (University of Lincoln, United Kingdom), Charlie Woodrow (University of Lincoln, United Kingdom), Shannon L Harrison (Univeristy of Lincoln, United Kingdom), Gregory P Sutton (Univeristy of Lincoln, United Kingdom), Denis C Deeming (Univeristy of Lincoln, United Kingdom)

chloekittengoode09@hotmail.co.uk

Mecopoda elongata (a bush cricket of the Subfamily Mecopodinae) are a jumping species of cricket, renowned for their ability to jump long distances. They jump using a muscle actuated system in which the force required for the jump is generated within the femoral muscles of the metathoracic legs. The force generated by these muscles results in a relatively fast jump during which an M.elongata spins about its centre of mass, pitching its body backwards prior to landing. In this study the jumps of 67 M.elongata were recorded, ranging from 0.014 g to 3.01 g (first instar to adult), for a total of 268 jumps. On average, as M.elongata increase in size their take off velocity scales with mass0.18 and the angular velocity (pitch only) decreases by mass-0.13 . In comparison, the locust (Schistocerca gregaria), a similar sized latch mediated spring actuated jumper, have a take-off velocity invariant to mass and an angular velocity which scales with mass-0.33 . Whilst M.elongata have a different relationship between mass and spin to S.gregaria, the ratio of translational kinetic energy to rotational kinetic energy for a jump, was proportional for both. On average, the energy budget of the cricket jump is distributed 98.8% to kinetic translational energy and 1.2% to rotational kinetic energy, whilst in the locust it is 98.7% and 1.3%, respectively. Despite utilising two different jumping mechanisms it seems that the ratio of energy distribution is independent of mass i.e. smaller insects rotate faster when jumping.

A12.77 COMPARATIVE ANALYSIS OF MUSCULOSKELETAL ANATOMY IN RELATION TO LOCOMOTOR MODE IN FROGS

Thursday 6 July 2023 16:30

Alice Leavey (University College London, United Kingdom), Marcello Ruta (University of Lincoln, United Kingdom), Christopher Richards (Royal Veterinary College, United Kingdom), Laura Porro (University College London, United Kingdom)

AliceLeavey@outlook.com

Amphibians exhibit complex anatomical features of the pelvis and limbs which enable them to employ a range of locomotor styles in a variety of environments, making them ideal organisms for investigating the relationship between morphology, function, ecology, and evolution. By digitally dissecting micro-CT scans, we investigate the link between skeletal and soft-tissue anatomy and locomotor mode, shedding new light on how functional demands

impact morphology. Skeletal measurements for 164 taxa from all 56 recognised anuran families indicate that hindlimb proportions differ significantly between species utilizing different locomotor modes, suggesting that each segment performs discrete functions. Skeletal morphology is also highly conserved in jumpers, regardless of habitat type, while broader anatomical solutions are found for swimmers, burrowers, and walkers. This is reflected by the morphology of semi-aquatic taxa, which is shaped more by requirements to jump than to swim. Additionally, we show how pelvic morphology, a key predictor of locomotor mode in anurans, should be considered along a morphological continuum rather than discrete types. Comparative analyses of muscle anatomy from a subset of 20 representative species show various trends between muscle size and locomotor mode. By combining this anatomical data with biomechanical models, we will obtain direct mechanical evidence for how variations in limb anatomy influence locomotor multi-functionality across the frog phylogeny. Ultimately, this work contributes towards constructing a workflow for inferring the locomotor behaviours of extinct taxa using fossil measurements.

A12.78 DYNAMIC SIMILARITY AND THE UNUSUAL SCALING OF MAXIMUM RUNNING SPEED

Thursday 6 July 2023 17:00

David Labonte (Imperial College, United Kingdom), Peter Bishop (Harvard University, United States), Taylor Dick (The University of Queensland, Australia), Christofer Clemente (University of the Sunshine Coast, Australia)

d.labonte@imperial.ac.uk

The variation of maximum running speed with animal size is of substantial ecological importance, and has thus long been a topic of interest in animal physiology and biomechanics. Remarkably, empirical data has it that running speed increases up to a critical body mass, and then decreases; the fastest animals are those of some intermediate size. This pattern is a noteworthy outlier among scaling relationships, which are typically monotonous, and can be described by simple power laws. Here, we show that the initial increase and subsequent flattening of maximum running speed with size arises from size-dependent physiological limits to muscle work output, set by the force-velocity and force-length properties of muscle. Beyond a critical size, maximum running speed decreases, because the gravitational force approaches the maximum muscle force, and so truncates the accessible muscle strain rate, and redirects muscle work from kinetic into gravitational potential energy. Both effects can be accounted for in classic dynamic similarity arguments, yielding two dimensionless numbers that can inform comparative work on both extant and extinct animals.

A12.79 DYNAMICS OF ‘ON THE FLY’ QUADRUPEDAL-TO-BIPEDAL WALKING TRANSITIONS IN BABOONS.

Thursday 6 July 2023 17:15

Peter Aerts (University of Antwerp, Belgium), Jana Goyens (University of Antwerp, Belgium), Gilles Berillon (CNRS, France),

Kristiaan D'Août (University of Liverpool, United Kingdom), François Druelle (CNRS, France)

peter.aerts@uantwerpen.be

Baboons can transition from quadrupedal to bipedal walking ‘on the fly’, i.e. without any significant interruption in their forward movement. Using an inverse approach, planar dynamics are deduced from (lateral view) video-recordings. Starting from the momentum-impulse theorem, possible strategies for such dynamical mode transitions are evaluated, and applied, first to an example sequence. The strategy used in this worked example boils down to: crouch the hind parts and sprint them underneath the rising body centre of mass. Forward accelerations are not in play. Key characteristics of this transition strategy were extracted: progression speed, hip height, step duration(frequency), foot positioning at touchdown with respect to the hip and the body centre of mass (BCoM), and congruity between the moments of the ground reaction force about the BCoM and the rate of change of the total angular moment. Statistical analyses across all available recordings of transitions (15 by 10 individuals) confirm this strategy is always used and is shared across individuals. The costs (in J kg−1 m−1 ) linked to such ‘on the fly’ transitions were estimated. These approximately only double those of both the preceding quadrupedal and subsequent bipedal walking. Given the short duration of the transition as such (<1 s), it is argued that the energetic costs to change walking posture ‘on the fly’ are negligible when considered in the context of the entire locomotor repertoire of baboons.

A12.80 THE EFFECT OF TAIL POSTURE ON LONGITUDINAL STABILITY IN A GLIDING BARN OWL

Thursday 6 July 2023 17:30

Jialei Song (Dongguan University of Technology, China),

Jorn A Cheney (University of Southampton, United Kingdom), Changyao Chen (Dongguan University of Technology, China), Richard J Bomphrey (Royal Veterinary College, United Kingdom), James R Usherwood (Royal Veterinary College, United Kingdom)

songjl@dgut.edu.cn

Birds can modify their aerodynamic characteristics by substantially changing the shape and position of their wings and tail, known as morphing. The tail, as an auxiliary lifting surface, plays an important role in lift and drag production and may also significantly affect longitudinal stability. In this study, we created a high-fidelity barn owl model using a point cloud obtained from high-speed photogrammetry of a real owl. We used this geometry in a computational fluid dynamics solver

to simulate the flow around the bird. The spread and pitch angles of the tail were adjusted to exhibit a series of postures and subsequently assessed for aerodynamic performance and static stability. The range of tail spread angles and pitch angles were each in excess of 40 degrees. Our preliminary study shows that the measured barn owl gliding posture and a large range of feasible alternative postures are unstable, and that tail morphing has a deterministic effect on the stability derivatives.

A12.81 SILK COCOONS - MULTI SCALE CHARACTERIZATION OF THEIR STRUCTURE

Thursday 6 July 2023 17:45

Nikolai Rosenthal (Max Planck Institute of Colloids and Interfaces, Germany),

Michaela Eder (Max Planck Institute of Colloids and Interfaces, Germany)

Nikolai.Rosenthal@mpikg.mpg.de

Silk is produced by a great variety of arthropods to actively create external structures which provide a great variety of functions e. g. protect the organism, its eggs, or is used to capture prey as well as creating a controlled micro-environment for temperature, humidity and gas exchange. The relationship between the composition, architecture and material properties of the silk will be explored by state-of-the-art imaging techniques, material characterization techniques and combined with simulations. Therefore, we analyze the 3-dimensional structural properties of silk cocoons on the meso-, micro and nanoscale. Micro-computed tomography was used to characterize different regions of the cocoons, the layering of the cocoon membrane, porosities, fiber orientation with respect to their functions. By Focused-ion beam SEM this will be extended to single filament in an attempt to characterize its structural features in 3D. To gain a more holistic understanding of the cocoon system, the spinning of the cocoon by the animal will be recorded and depending of the analysis evaluated against existing research on the spinning process and its different stages. The overarching goal is the understanding of the material-form-function relationship of the silken composites.

A12.82 INDIVIDUAL DIFFERENCES IN MULTI-OBJECTIVE CONTROL OF OBSTACLE NEGOTIATION DURING WALKING

Friday 7 July 2023 09:00

Kat Daniels (Manchester Metropolitan University, United Kingdom), Maria Fuentes Conde (Manchester Metropolitan University, United Kingdom), Liis Uiga (Manchester Metropolitan University, United Kingdom)

k.daniels@mmu.ac.uk

locomotion in humans and other animals. However, little is known about how energy expenditure interacts with other task goals to shape adaptive gait over complex terrain. Here, we investigate whether individual differences in psychological characteristics and physical performance capabilities affect human locomotor behaviour and

prioritisation of energy optimality when walking over obstacles in the path of travel. Thirteen adult participants completed a set of psychological questionnaires to quantify aspects of personality, risk propensity, trait anxiety, movement-specific reinvestment and decision-specific reinvestment. Participants then undertook a laboratory-based obstacle negotiation task in which they were required to choose between discrete multi-step obstacle negotiation manoeuvres to cross a ‘hole’ in the path of travel during walking. The depth and length of the hole were varied from trial to trial and whole-body optical motion data were recorded. Following this, a second set of trials were performed in which participants were instructed to use non-preferred manoeuvres to negotiate the obstacle. Lastly, self-perceived and demonstrated maximum step length and step-up heights were measured alongside participant strength metrics and habitual activity levels. Participants tended to choose manoeuvres that minimised mechanical energy cost of transport for the complete obstacle negotiation task but behaviour was modulated by individual differences in psychological metrics and physical capability. Understanding the ways in which multiple constraints and objectives interact to influence movement strategies is key to understanding and predicting locomotor behaviour in complex real-world environments.

A12.83 PLANTIGRADE FEET CAN AVOID WORK THROUGH SERIAL LINKAGES

Friday 7 July 2023 09:30

Delyle T Polet (Royal Veterinary College, United Kingdom), James R Usherwood (Royal Veterinary College, United Kingdom)

dpolet@rvc.ac.uk

A plantigrade posture in quadrupedal locomotion is widely considered to be less economical than digitigrade or unguligrade, as the former reduces the effective leg length and limits elastic storage and return. Yet crocodylians and most lepidosaurs retain plantigrade feet and have no less economical locomotion than mammals of similar size. Here we show how animals can exploit plantigrade posture to avoid work through serial linkages. As the center of pressure moves anteriorly during stance, the foot can "roll up" like a wheel, keeping forces relatively vertical and body velocity relatively horizontal. Likewise, during sprawling locomotion, the lateral motion of the center of pressure can be accommodated by a "spherical" foot- where joints lock out so as to emulate the surface of a sphere, maintaining relatively horizontal motion of the body. We compare this perspective on plantigrade locomotion to the prevalent inverted pendulum and spring-mass models of locomotion, with reference to biological data.

A12.84 THE COLLISIONAL GEOMETRY OF ECONOMICAL WALKING PREDICTS HUMAN LEG AND FOOT SEGMENT PROPORTIONS.

Friday 7 July 2023 09:45

Jim Usherwood (The Royal Veterinary College, United Kingdom)

leggleton1@sheffield.ac.uk

Human walking appears complicated, with many muscles and

joints performing rapidly varying roles over the stride. However, the function of walking is simple: to support body weight as it translates economically. Here, a scenario is proposed for the sequence of joint and muscle actions that achieves this function, with the timing of muscle loading and unloading driven by simple changes in geometry over stance. In the scenario, joints of the legs and feet are sequentially locked, resulting in a vaulting stance phase and three or five rapid ‘mini-vaults’ over a series of ‘virtual legs’ during the step-to-step transition. Collision mechanics indicate that the mechanical work demand is minimised if the changes in the centre of mass trajectory over the step-to-step transition are evenly spaced, predicting an even spacing of the virtual legs. The scenario provides a simple account for the work-minimising mechanisms of joints and muscles in walking, and collision geometry allows leg and foot proportions to be predicted, accounting for the location of the knee halfway down the leg, and the relatively stiff, plantigrade, asymmetric, short-toed human foot. 10.1098/rsif.2022.0800.A range of toys or 'low fidelity physical demonstrators’ will be presented – along with plans and samples – showing the key linkages and collisional principles.

A12.85 WHAT DETERMINES INTRASPECIFIC VARIATIONS IN WALKING ENERGETICS?

Friday 7 July 2023 10:00

James P Charles (University of Liverpool, United Kingdom), Barbara Grant (University of Liverpool, United Kingdom), Karl T Bates (University of Liverpool, United Kingdom)

j.charles@liverpool.ac.uk

There is considerable variation in the metabolic cost of transport (CoT) within modern human populations, however the mechanisms behind this are unclear. Recent work has shown that various aspects of lower-limb musculoskeletal anatomy are not correlated with the cost of walking, hinting that variations in musculotendon function may be more important. Here, we test this hypothesis using 10 subject-specific lower-limb musculoskeletal models to simulate walking over different surfaces to predict how muscle efficiency and function are affected by terrain type, and how and why these vary between individuals. In all subjects, CoT increased with terrain compliance alongside an increase in positive muscle work and efficiency. Interestingly, while the muscles crossing the hip and knee joints functioned more efficiently on the compliant surfaces, the more distal muscles functioned less efficiently. A lower CoT on these surfaces was found to be associated with an increase in thigh muscle efficiency, which was in turn associated with a reduced mass of the distal lower limb relative to the proximal lower limb, as well as less hip and knee flexion. Additionally, there were increases in the spring-like function of these proximal muscles and tendons on the compliant substrates and decreases in the distal muscles, variations which were related to increases in overall muscle efficiency and decreases in locomotor cost. Overall, these results further the understanding of how intra-specific variations in anatomy, physiology and biomechanics impact vertebrate functional performance.

A12.86 THE EVOLUTION OF LOCOMOTOR PERFORMANCE AND MOVEMENT COMPLEXITY IN SPIDERS

Thursday 6 July 2023 10:15

Jonas O Wolff (University of Greifswald, Germany), Michael Kelly (Macquarie University, Australia), Kawsar Khan (Freie Universität Berlin, Germany), Kaja Wierucka (University of Zürich, Switzerland), Ryan Shofner (University of New South Wales, Australia), Shahan Derkarabetian (Museum of Comparative Zoology Harvard University, United States)

j.wolff@uni-greifswald.de

The ability to move fast is a key trait of many predatory strategies, but it also highly energy demanding, and should thus be under competing selective pressures. Here we tested, if the evolution of locomotor performance correlates with predatory strategy in spiders: the striking of prey versus the trapping of prey with a web. To test this we combined a phylogenomics approach with comparative kinematic analyses from high speed video recordings. We found that running speed was poorly correlated with the use of webs as prey capture devices – both traits showed mosaic, independent evolutionary patterns. We assume that counter-strategies of some prey that reduce the efficiency of silk snares cause a maintenance of the selective pressure on speed in some web builders. In the second half of the talk, I will demonstrate how geometric morphometrics can be used as a tool to understand the evolution of movement patterns. Spiders use species specific spinneret choreographies to construct the anchor points of silk lines. The way how the spinnerets are moved has direct effects on the structure and mechanical properties of the constructed anchor point. The calculation of ancestral spinning patterns showed that during their evolution spiders repeatedly transitioned to a more efficient choreography resulting in stronger anchorages. These examples show that broad scale phylogenetic comparative analyses are a useful tool to understand the dynamics and underlying mechanisms generating the observed diversity of locomotor performances and styles.

A12.87 GENERAL MEETING FOR THE OPEN BIOMECHANICS INTEREST GROUP

Thursday 6 July 2023 11:00

Nicolai Konow (U. Mass Lowell, United States)

Nicolai_Konow@uml.edu

During this half-hour long meeting, the Convener (Nicolai Konow) will present the annual status report for the interest group, and the membership will be invited to discuss and vote on the proposed name-change of the intererst group to either (i) Form and Function, (ii) Structure and Motion, (iii) Biomechanics and Functional Morphology, or (iv) leave as is. There will also be opportunity for the membership to advertise upcoming events or meetings by sending a slide to Nicolai_Konow@uml.edu.

A13 OPEN ANIMAL

ORGANISED BY: JACK THOMSON (UNIVERSITY OF LIVERPOOL)

A13.1 THE EFFECT OF CAPTIVITY PARAMETERS ON SCORPION VENOM SECRETION PHYSIOLOGY: IMPLICATIONS FOR VENOM PRODUCTION AND QUALITY

Tuesday 4 July 2023 09:00

Mouad MKAMEL (Mohammed VI University of Sciences and Health, Morocco)

contact@mkamelmouad.com

Scorpion venom has been the subject of intense research due to its potential therapeutic applications. However, the physiology of scorpion venom secretion, particularly in relation to captivity parameters, remains poorly understood. This study aimed to investigate the effect of captivity parameters on scorpion venom secretion physiology and its implications for venom production and quality.

A total of 50 scorpions were maintained in captivity under different conditions, including temperature, humidity, light cycle, and feeding frequency. Scorpion venom was extracted using electrical stimulation, and the quantity and quality of venom were analyzed using various biochemical and biophysical techniques.

Our results showed that captivity parameters had a significant effect on scorpion venom secretion physiology. Scorpions maintained at higher temperatures and humidity levels exhibited higher venom yields, while those maintained under prolonged darkness had lower venom yields. Feeding frequency had a complex effect on venom secretion, with scorpions fed more frequently showing both higher and lower venom yields depending on the duration of captivity.

Furthermore, we found that captivity parameters also influenced the biochemical and biophysical properties of scorpion venom, with changes in venom composition and potency observed under different conditions.

Overall, our study provides valuable insights into the physiology of scorpion venom secretion and highlights the importance of optimizing captivity parameters for maximizing venom production and quality. These findings have implications for the development of novel therapeutic applications of scorpion venom.

Katherine A Sloman (University of the West of Scotland, United Kingdom), Myriam Vanderzwalmen (University of the West of Scotland, United Kingdom), Daniel Sanchez Lacalle (University of the West of Scotland, United Kingdom), Louise Ross (University of the West of Scotland, United Kingdom), Andrew Hursthouse (University of the West of Scotland, United Kingdom), Iain McLellan (University of the West of Scotland, United Kingdom), Mhairi E Alexander (University of the West of Scotland, United Kingdom), Fiona L Henriquez (University of the West of Scotland, United Kingdom), Donna Snellgrove (Waltham Petcare Science Institute, United Kingdom)

katherine.sloman@uws.ac.uk

Almost all home aquaria contain substrate which hobbyists choose to add either as a form of enrichment that they feel enhances the behaviour or welfare of the fish or tank, or simply for aesthetic purposes. However, the impacts of tank substrate as enrichment for ornamental fishes is limited. Previous research has shown that substrate can induce foraging in some species, but a major drawback to the addition of substrate is the harbouring of pathogenic bacteria. Here, we present results from a suite of studies that have considered why people add substrate to their home aquarium, and the effects of substrate on water quality, fish behaviour and bacterial presence. We found that substrate type (e.g. gravel, sand, coloured gravel) affected water quality (temperature, oxygen, pH, TAN, unionised ammonia, nitrate, Ca2+ , Na+ , Mg2+ and K+ ) and bacterial presence but that the effects observed in simulated home aquaria were also dependent on season. Substrate type clearly has the potential to affect both fish behaviour and water quality of home aquaria, with more understanding required in relation to fish welfare.

Tuesday 4 July 2023 09:00

Tuesday 4 July 2023 09:30

Ellis Larcombe (University of the West of Scotland, United Kingdom), Samantha Hendrie (University of the West of Scotland, United Kingdom), Mhairi E Alexander (University of the West of Scotland, United Kingdom), Donna Snellgrove (Waltham Petcare Science Institute, United Kingdom), Fiona L Henriquez (University of the West of Scotland, United Kingdom), Katherine A Sloman (University of the West of Scotland, United Kingdom)

Ellis.larcombe@uws.ac.uk

A13.3 COMMERCIALLY AVAILABLE ANTIMICROBIALS INFLUENCE ORNAMENTAL FISH BEHAVIOUR AND THE ENVIRONMENTAL MICROBIOME IN HOME AQUARIA

Ornamental fishes are susceptible to a range of pathogenic microorganisms which if untreated can result in extensive mortality. Infections within a commercial setting are usually resolved with the use of antimicrobials unavailable to the general consumer. Alternative ‘over-the-counter’ treatments exist for the home aquarist, but how they affect fish behaviour, and the tank environmental microbiome is not understood with possible implications for fish welfare. Often treatments may be used prophylactically and not always following manufacturer’s guidelines. To investigate the effects of these treatments, two popular antimicrobial products were chosen and used to treat simulated home aquaria containing healthy Danio rerio and Corydoras aeneus. Tanks were treated with product A, B, a combination of A and B, or were untreated controls. During and after treatment, behavioural observations were undertaken and DNA extracted, purified, and sequenced from pooled water samples from each treatment for microbiome analysis. Products A and B, singly and in combination, increased the latency of fish to feed, but this effect was relatively short lived. Levels of aggression and erratic movement in D. rerio were also affected by treatment. A few pathogenic bacteria genera were identified including Aeromonas, Flavobacterium, and Plesiomonas and the aromatic compound degrading genera Novosphingobium were found in higher abundance in tanks treated with product A, which contains aromatic compounds. This research demonstrates commercially available antimicrobial products can influence the behaviour of ornamental fishes and may alter the tank environmental microbiome by providing energy sources for niche bacterial species.

A13.4 EXPLORING THE POTENTIAL FOR FISHING-INDUCED EVOLUTION IN THE ORNAMENTAL FISHING INDUSTRY

Tuesday 4 July 2023 09:45

Mar Pineda (University of Glasgow, United Kingdom), Daiani Kochhann (Universidade do Vale do Acaraú, Brazil), Kathryn Elmer (University of Glasgow, United Kingdom), Jan Lindstrom (University of Glasgow, United Kingdom), Adalberto Val (INPA- National Institute for Amazonian Research, Brazil), Shaun Killen (University of Glasgow, United Kingdom)

m.pineda.1@research.gla.ac.uk

There is increasing evidence from commercial and recreational fisheries that fishing targets individuals with certain physiological or behavioural traits. However, the impact of selectively removing individuals has been overlooked within the context of the ornamental fishing industry. This is surprising, not only because it is a highly selective fishery, but also because potential evolutionary effects may be apparent sooner in smaller, tropical fish. Here, we examine the relationship between individual phenotype and vulnerability to capture in the cardinal tetra (Paracheirodon axelrodi) using both lab-based simulations and observations in the field. In the lab, vulnerability to capture was assessed using catchability assays. Metabolic and behavioural traits were then measured for each individual. In the Brazilian Amazon, cardinal tetra were captured using traditional passive and active fishing gears. Underwater footage of the trapping process was obtained to gain insight into which fish are caught, and which escaped. Cardinal tetras were then transferred to aquarium facilities to examine their physiological (swim performance) and behavioural (risk-taking and exploration) traits. Ongoing analyses examine whether fishing associated selection on individual traits depends on fishing gear type or if the impact is context specific. The results from this study provide one of the first examples of studying fisheries selection within the

A13.5 THE GENETIC BASIS OF HATCHERY DOMESTICATION IN RAINBOW TROUT AND ITS IMPACTS ON PERFORMANCE AND SURVIVAL IN THE WILD

Tuesday 4 July 2023 10:00

Madison L Earhart (University of British Columbia, Canada), Matt J Thorstensen (University of Manitoba, Canada), Clark McMaster (University of British Columbia, Canada), Tessa S Blanchard (University of British Columbia, Canada), Nicholas Strowbridge (University of Glasglow, United Kingdom), William S Bugg (University of Manitoba, Canada), Rashpal Dhillon (University of British Columbia, Canada), Robert H Devlin (Fisheries and Oceans Canada, Canada), Patricia M Schulte (University of British Columbia, Canada)

earhart@zoology.ubc.ca

Rainbow trout, Oncorhynchus mykiss, is an economically and recreationally important species worldwide that is both farmed for human consumption and hatchery-reared and released for conservation and recreational fishing. Both intentional and unintentional selection during captive rearing has resulted in a domesticated phenotype that may have lower fitness in natural environments when compared to wild fish. However, the genetic mechanisms underlying fish domestication, or the “captive” phenotype, are largely unknown, and identifying loci associated with different domesticated phenotypes is crucial to understanding how the introduction of this genetic variation could affect wild fish populations. In this study, we investigated the genetic basis of hatchery domestication and how domesticated alleles affect various phenotypes and survival by creating F2 crosses from F1 (domestic x wild) parents and releasing the resulting F2 alevin into semi-natural ponds. Six months after stocking, fish were recaptured, phenotyped, and sampled for subsequent SNP-Chip genotyping to assess the genetic basis of trait variation and survival via a genomewide association study (GWAS). There was substantial variation among the surviving fish from the semi-natural ponds in multiple phenotypes including hypoxia tolerance, body size, morphometrics, and colour patterns. Additionally, principal component analysis revealed multiple distinct genotypes in the surviving pond fish, suggesting fish with both wild and domesticated alleles were re-captured. Many of the measured traits differed between genotypes, and had significant associations with genetic variants, suggesting a genetic basis for variation in traits that may differ between domesticated and wild rainbow trout.

Tuesday 4 July 2023 10:15

ornamental fishing industry and will further our understanding of the potential impacts of this growing fishery.

A13.6 APPLYING STRESS PHYSIOLOGY

TOOLS

TO UNDERSTAND THE PHYSIOLOGICAL RESPONSE OF WILDLIFE AND DOMESTICATED ANIMALS TO ENVIRONMENTAL STRESSORS

Edward Narayan (The University of Queensland, Australia)

e.narayan@uq.edu.au

Animals naturally feel or perceive environmental change using physiological and behavioural mechanisms. The key questions that often remain unanswered are; can animals perceive environmental change; do they have the capacity to adjust to human related environmental change; and if adaptation does not occur then what are the likely consequences? These research questions are relevant to animal welfare science and have been explored using several domesticated animal models and remains a key question for wildlife. Stress occurs as a result of any unpleasant change in an animal’s surroundings. One of the key neuroendocrine systems that is responsive to stress is the hypothalamus-pituitary adrenal (HPA) axis. Activation of the HPAaxis releases stress hormones such as glucocorticoids from adrenal glands. With current modern technological advancements in biomarker detection techniques, steroid metabolites can be readily measured in non-invasively obtained samples such as urine, faeces and hair. This technique can be applied to explore specific research questions related to stress. This method provides a quantitative way of profiling the stress responses of individual animals within a population, distinguishing between acute and chronic stress and establishes relationships with animal health and welfare. Examples will include livestock species such as sheep in relation to heat stress, Asiatic bears rehabilitation, koalas in relation to environmental trauma and disease and frogs in relation to ecological applications. Thus, the presentation will highlight the link between stress physiology and animal welfare and demonstrates the value of non-invasive endocrinology research in advancing animal welfare.

A13.7 HOW DOES THERMALLATITUDINAL ADAPTATION VARY IN THE TROPICAL FRESHWATER CRAB BARYTELPHUSA CUNICULARIS?

Tuesday 4 July 2023 13:30

Lucy M Turner (University of Plymouth, United Kingdom), Christopher J Thorpe (University of Plymouth, United Kingdom), Michael Collins (University of Plymouth, United Kingdom), Smrithy Raj (University of Kerala, India), Tripti Shukla (National Centre for Biological Sciences Tata Institute of Fundamental Research Bangalore, India), John I Spicer (University of Plymouth, United Kingdom), Mairi E Knight (University of Plymouth, United Kingdom), Krushnamegh Kunte (National Centre for Biological Sciences Tata Institute of Fundamental Research Bangalore, India)

lucy.m.turner@plymouth.ac.uk

Environmental temperature affects the thermal performance of aquatic ectotherms and, consequently may significantly influence their biogeographic distribution. Adaptation of local populations along latitudinal gradients to thermal conditions has been demonstrated in a range of marine and terrestrial taxa but comparatively little is known for freshwater species, particularly those from tropical and sub-tropical regions, which remain understudied. The freshwater crab Barytelphusa cunicularis is widely distributed throughout India’s vast riverine network. Thermal sensitivity of different populations of B. cunicularis was estimated by collecting crabs from populations along a 1,700 km latitudinal gradient, and from 5-670 m elevation pre and post monsoon in south-west India. Crabs were then maintained in the laboratory at T = 25 or 30°C for 7 days before measuring their rates of aerobic metabolism (MO2) and critical oxygen tension (Pcrit ).

This allowed us to test for any population differences in the effects of latitude, altitude, season (as a proxy for rainfall and water temperature), and/or warming. MO2 and Pcrit varied by population depending on latitude, altitude and season. Therefore, while molecular data confirm this widely distributed crab is a single species, the physiology indicates some local adaptation, suggesting that the large geographical range size of this crab is underpinned, to some extent, by physiological plasticity. These data help to inform our understanding of physiological diversity in tropical freshwater systems and also have applications to inform the physiological suitability of this crab as a novel aquaculture species in India.

A13.8 CELL SIZE AND FATTY ACID MODULATIONS CONTRIBUTE TO TEMPERATURE TOLERANCE OF AN ECTOTHERM

Tuesday 4 July 2023 13:30

France Dufresne (Université du Québec à Rimouski, Canada), Ivan Pecl (Université du Québec à Rimouski, Canada), Pierre Blier (Université du Québec à Rimouski, Canada)

france_dufresne@uqar.ca

Cell size has recently been recognized as an important trait in understanding temperature tolerance in ectotherms. As small bodies are often composed of small cells with a bigger membrane surface area relative to volume than larger cells, they may support a greater capacity for oxygen transport which could explain the greater temperature tolerance of small ectotherms. By contrast, larger cells could provide metabolic advantages in the cold.In addition to cell size, fatty acid profiles can also be modified to maintain an optimal membrane fluidity under changing temperatures. In this study, we examined the contribution of cell size, body size, and fatty acid profiles on temperature tolerance in the freshwater microcrustacean Daphnia. Ctmin and Ctmax were measured in 17 diploid and triploid Daphnia pulex clones acclimated to 16°C and 24°C for several generations. Clones raised under low temperature had lower Ctmin and lower Ctmax than clones raised under higher temperatures. Polyploid clones had larger cells than diploid clones under both rearing temperatures. Ctmax but not Ctmin was negatively correlated with cell size and body size. A strong negative relationship was found between EPA and CTmax with a change of -0.72°C in CTmax for every change in one standard deviation of EPA. Polyploid clones had higher Ctmax and higher Ctmin than diploid clones. Our results suggest that the larger cells of polyploid clones may be disadvantageous under higher temperatures but beneficial under lower temperatures, thus explaining their differential distribution at high latitudes.

Tuesday 4 July 2023 14:00

Félix P. Leiva (Alfred Wegener Institute, Germany), Mauro Santos (Universitat Autonòma de Barcelona, Spain), Enrico L. Rezende (Pontificia Universidad Católica de Chile, Chile), Wilco CEP Verberk (Radboud University Nijmegen, Netherlands)

A13.9 VARIATION OF THERMAL DEATH TIME CURVES IN A MODEL ECTOTHERM

felixpleiva@gmail.com

Thermal tolerance has received much scientific interest because of its relationship with the vulnerability of a species to warming. However, when assessing the thermal limits of ectotherms and the underlying drivers, the methodology is important, notably the duration of the assays. By applying thermal death times curves, which incorporate the intensity and duration of heat stress, we investigated the ability to survive heat stress in multiple inbred lines of Drosophila melanogaster. The lines were selected to differ markedly in body size and cell size as these traits have been hypothesised to shape thermal tolerance via their effects on oxygen supply and demand. As a direct test of this idea, we also tested the survival to heat stress under low oxygen conditions. Low oxygen conditions markedly reduced survival time in D. melanogaster, especially when heat stress was mild and when flies were exposed for longer periods. Variation in heat tolerance among lines could be partly related to cell size and body size differences, especially under chronic exposure to high temperatures. Because differences in heat tolerance were manifested at different timescales, our results underscore the need to close the gap between responses to acute, typically measured in laboratory studies, and chronic timescales.

A13.10 DIFFERENT PROTEOMIC RESPONSES TO TEMPERATURE STRESS IN BOLD AND SHY BEADLET SEA ANEMONES

Tuesday 4 July 2023 14:15

Jack S Thomson (University of Liverpool, United Kingdom), Daniel K Maskrey (University of Liverpool, United Kingdom), Robert J Beynon (University of Liverpool, United Kingdom), Lynne U Sneddon (University of Gothenburg, Sweden), Kathryn E Arnold (University of York, United Kingdom), Catarina Franco (University of Liverpool, United Kingdom), Deborah M Simpson (University of Liverpool, United Kingdom), Philip J Brownridge (University of Liverpool, United Kingdom), David CC Wolfenden (University of Gothenburg, Sweden)

zaralouisecowan@gmail.com

Animal personalities are often correlated with stress physiology, but the underlying mechanisms remain poorly understood. Nevertheless, the relationship can help us understand how populations will respond to environmental challenges, including climate change. We can elucidate these mechanisms by examining molecular processes, and exploration of the proteome in particular can provide a real-time picture of responses to challenge. Here, for the first time among invertebrates, we have used a proteomics approach to assess how bold and shy beadlet anemones, Actinia equina, respond to thermal stress. Anemones (n=24) were assessed for boldness based on startle response time, and were then either held at 11 deg. C for 17 days (Control) or exposed to a graduated temperature increase to 23 deg. C over the same period (Treatment). Proteins were quantified in the tentacles of anemones using LC-MS/MS, comparing between bold-shy, Control-Treatment, and their interaction. We found a strong proteomic temperature response in A. equina, with individuals down-regulating biosynthetic proteins and apoptotic pathways, in favour of up-regulating proteins involved with stress-resistance. We further found a whole-proteome effect of personality-type which was only apparent under heat stress: shy animals down-regulated biosynthetic pathways to a greater degree than bold animals, and showed reduced up-regulation of proteins associated

with cellular maintenance, proliferation, and stress-resistance. Both strategies doubtless have adaptive value, but these data suggest some personality-types may be placed under greater selective pressure under climate change scenarios, based on their stress physiology, than others.

A13.11 EFFECTS OF OXYGEN SUPERSATURATION ON THERMAL TOLERANCE IN AQUATIC ECTOTHERMS

Tuesday 4 July 2023 14:30

Graham D Raby (Trent University, Canada), Jeremy De Bonville (U Montreal, Canada), Leroy Reynolds (Trent University, Canada), Dominique Roche (Carleton U, Canada), Zara L Cowan (NTNU, Norway), Ben Speers-Roesch (U New Brunswick, Canada), Fredrik Jutfelt (U Gothenburg, Sweden)

grahamraby@trentu.ca

The supply of oxygen to tissues is one potential mechanism to explain thermal tolerance in water breathing ectotherms. One intuitively appealing way to test the role of oxygen is to provide fish with more oxygen supply (in the water) when assessing their tolerance of high temperatures. In some aquatic habitats, oxygen can become temporarily supersaturated (i.e., >100% air saturation) because of plant respiration or turbulent flows. A recent study reported that oxygen supersaturation (140% of air saturation) markedly increased upper lethal temperatures in six aquatic tropical ectotherms. Those important findings suggested that naturally occurring oxygen supersaturation in aquatic habitats could help ectotherms survive severe heat waves. In this study, we assessed the effects of oxygen supersaturation on critical thermal maximum (CTmax) in 10 temperate aquatic ectotherms, including four freshwater species and six coastal marine species, including a mix of fishes and invertebrates.

A13.12 THE EFFECT OF UP- AND DOWNSELECTED THERMAL TOLERANCE AND ACUTE TEMPERATURE EXPOSURE ON ZEBRAFISH SOCIAL BEHAVIOUR

Tuesday 4 July 2023 14:45

Daphne Cortese (University of Glasgow, United Kingdom), Amelia Munson (University of Glasgow, United Kingdom), Shaun Killen (University of Glasgow, United Kingdom), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway)

daphne.cortese@glasgow.ac.uk

Many animals are social and live in groups. Group-living has many advantages, including protection against predators, access to resources and breeding opportunities. However, there are trade-offs between the advantages and the potential costs associated with group-living, such as competition for resources and mates. Those trade-offs may vary between individuals with different phenotypes and as a function of the environment. However, surprisingly little is known on the relationship between individual phenotype and social behaviour and the potential interaction with the surrounding environment. In

ectotherms, most physiological processes depend on environmental temperature, and large inter-individual variation in thermal tolerance has been documented. In this study, using juvenile zebrafish (Danio rerio) up- or down-selected for their upper thermal tolerance and reared at 28˚C, we explored how individual differences in upper thermal tolerance and exposure to acute increase in temperature (34˚C) affect behaviour, including individual sociability and group cohesion. Preliminary results show that at acclimation temperature up-selected individuals are more social than down-selected individuals but these differences disappear when fish are exposed to the higher temperature. This change across environmental temperature is mainly driven by a decrease in sociability in up-selected fish when exposed to higher temperature. These results suggest that in up-selected individuals, at acclimation temperature, the benefits of group-living surpass the costs but this trade-off seems to change across temperatures. Groups composed of individuals with different physiological traits may exhibit different behaviors, which has the potential to affect group functioning, perhaps with repercussions on foraging success and predator avoidance.

A13.14 ATLANTIC SALMON (SALMO SALAR) GILL FILAMENTS CAN REGENERATE FOLLOWING PHYSICAL DAMAGE

Tuesday 4 July 2023 15:30

Ensiyeh Ghanizadeh-Kazerouni (The University of British Columbia, Canada), Phillip R. Morrison (The University of British Columbia, Canada), Jonathan M. Wilson (Wilfrid Laurier University, Canada), Simon R.M. Jones (Fisheries and Oceans Canada, Canada), Colin J. Brauner (The University of British Columbia, Canada)

ghanizad@zoology.ubc.ca

Complex gill disorder (CGD) causes physical damage to gill filaments of marine farmed Atlantic salmon and greatly compromises gill physiological functions. We used a gill filament resection model to investigate regeneration and the cytological and functional capacity of regenerated tissue in Atlantic salmon in freshwater.

Fish were subjected to two levels of filament resection; 30% and 50% of filament distal length removed from 16 filaments on first branchial arch. Filament length was measured in the same 8-12 individuals at 1, 2, 4, 8, 12, 16, and 20 weeks post-resection (wpr). Additional resected and control fish were terminally sampled at these times for immunohistochemistry and Na+ /K+ -ATPase (NKA) activity measurement.

Tuesday 4 July 2023 15:30

Madison Schumm (The University of Texas at Austin Marine Science Institute, United States), Andrew Esbaugh (The University of Texas at Austin Marine Science Institute, United States)

mschumm7@utexas.edu

Marine fish are expected to cope with environmental stress through modifications to their physiology and behaviour to meet the demands of their new environment. Thermal stress associated with climate change is of particular concern for fish because increased temperatures lead to elevated baseline metabolic demand. Increases in metabolism must be supported by concomitant increases in resource uptake and supply, and thus, may be coupled to the expression of behavioural traits that facilitate resource acquisition, such as activity and exploration. Energy demand may further increase risk-taking and reduce behaviours thought to diminish predation risk in fish (e.g., shoaling and scototaxis). On this background, our goal was to evaluate changes to behavioral traits, metabolic rate and the relationship between behaviour and metabolic rate across two temperatures in an estuarine model teleost, the sheepshead minnow (Cyprinodon variegatus). Fish were acclimated to 22°C or 32°C for 14-days and standard and routine metabolic rates (SMR and RMR, respectively) were measured. Fish were subsequently subjected to a suite of behavioural assays to assess activity, exploration, sociability, and anxiety. As expected, warmer temperatures increased SMR, but surprisingly RMR was not affected by warming. Interestingly, the warm acclimation altered the relationships among behavioral traits and significantly increased measures of activity. There was no correlation between behaviours and metabolic traits in individuals acclimated to either temperature. Our data indicate that while both metabolism and behaviour show flexibility with warming, there is no apparent link between the two.

At 20-wpr, 38% of the resected filament length was regenerated in both resection groups. However, 50% resected filaments showed significantly higher absolute regeneration (mm) than 30% resected filaments. The regeneration rate varied significantly between individuals, but was not correlated with initial body size, condition factor, or overall fish growth rate. Immunohistochemistry showed an increase in cell proliferation at the filament tip shortly after resection and Neuroepithelial cells (NECs), nerve fibres, and ionocytes were identified as early as 4-wpr. In both resected groups more than 50% and 90% of NECs were innervated by 12- and 20-wpr, respectively. Gill NKA activity in regenerated tissue was not significantly different from that of internal control and non-resected control group. Our results demonstrate that the gill of Atlantic salmon is capable of significant regeneration and functional recovery, which has important implications for recovery from CGD in aquaculture.

A13.15 THE ROLE OF COELOMOCYTES IN TISSUE REGENERATION OF CD-EXPOSED EARTHWORMS

Tuesday 4 July 2023 16:00

Gerhard Paul Aigner (University of Innsbruck Institute of Zoology, Austria), Veronika Peer (University of Innsbruck Institute of Zoology, Austria), Birgit Fiechtner (University of Innsbruck Institute of Zoology, Austria), Claudio Adriano Piechnik (University of Innsbruck Institute of Zoology, Austria), Martina Höckner (University of Innsbruck Institute of Zoology, Austria)

gerhard.p.aigner@uibk.ac.at

Earthworms are well-established model organisms for exploring the molecular mechanisms of regeneration and for testing the

A13.13 PHENOTYPIC PLASTICITY OF METABOLISM AND BEHAVIOUR AFTER TEMPERATURE ACCLIMATION IN SHEEPSHEAD MINNOWS (CYPRINODON VARIEGATUS)

effects of the immunotoxic agent cadmium (Cd). Coelomocytes are cells of the innate immune system of earthworms that detoxify Cd through the induction of metallothionein 2 (MT2). Further, these cells express immunity related toll-like receptors (TLRs) and are related to regeneration capability. To date, the relation of molecular mechanisms in regeneration and Cd detoxification are not well understood in earthworms. Hence, we exposed healthy and amputated Lumbricus terrestris to 50 mg/kg dry soil Cd and sampled weekly regenerating tissue and the anterior tissue section over three weeks to quantify gene expression of two MTs, two TLRs and of the transcription factors cyclic amp responsive element binding protein (CREB) and activating transcription factor 7 (ATF7), which were suggested important cofactors of MT2 induction. Coelomocyte-specific gene expression of MT2 and of two TLRs was significantly upregulated and restricted to regenerating tissue. The reason for a lacking gene expression anterior of the wound site, might be the location of coelomocytes, which accumulate in the injured region. ATF7 and CREB gene activity did not correlate with gene expression of MT2. Therefore, we cannot confirm a previously suggested role of ATF7 and CREB in MT2 gene regulation. Interestingly, principal component analysis revealed that injury, but not Cd, lead to separation of the treatment groups.

A13.16 WHAT SEA LAMPREY, CATS AND HYENAS HAVE IN COMMON.

Tuesday 4 July 2023 16:15

Michael P Wilkie (Dept. Biology Wilfrid Laurier University, Canada), Michael J Lawrence (University of Manitoba, Canada), Phil Grayson (University of Manitoba, Canada), Dejana Mitrovic (University of Waterloo, Canada), Leslie M. Bragg (University of Waterloo, Canada), Mark R. Servos (University of Waterloo, Canada), Margaret F Docker (University of Manitoba, Canada), Ken M Jeffries (University of Manitoba, Canada)

mwilkie@wlu.ca

The pesticide 3-trifluoromethyl-4-nitrophenol (TFM) is used to control invasive, blood-feeding sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes of North America, where they decimated fisheries in the mid-1900s. Lampreys are more sensitive to TFM than other aquatic biota due to their relatively low capacity to detoxify TFM using UDP-glucuronosyltransferase (UGT) enzymes. UGTs likely evolved in animals to detoxify phenolic compounds produced by plants as a defense against herbivory. Hyper-carnivorous mammals such as domestic and wild cats, and hyenas, however, have a lower capacity to use UGTs, likely because they have less need to detoxify phenols. To determine if sea lamprey have a lower diversity of UGTs and less flexibility to detoxify phenolic compounds, we analyzed whole transcriptome sequencing data to compare their ugt gene expression patterns to an omnivorous sunfish species, the bluegill (Lepomis macrochirus), following TFM exposure. Bluegill were ~10-fold more tolerant to TFM than lamprey, with ~95% less TFM accumulation in muscle following 24h of exposure. Bluegill had a greater diversity of ugt genes (17) in liver and gills than lamprey (6), and their transcriptome was more responsive to TFM, characterized by 16- and 28-fold increases in ugt3 expression in gill and liver, plus smaller increases in ugt2b9. No differentially expressed ugt’s were observed in lamprey after TFM exposure. We propose that the lamprey’s greater sensitivity to TFM is related to its limited consumption of phenolic compounds, resulting in reduced selective pressure to evolve a more diverse suite of UGTs over the last 350 million years.

A13.17 AIR POLLUTION, DIETARY FATTY ACIDS AND INFECTION INFLUENCE AVIAN OXIDATIVE STRESS STATE, BUT IN DIFFERENT WAYS

Tuesday 4 July 2023 16:30

Ann-Kathrin Ziegler (Lund University, Sweden), Johan Kjellberg-Jensen (Lund University, Sweden), Lucía G. Jiménez Gallardo (Universidad Complutense Madrid, Spain), Jenny Rissler (Lund University, Sweden), Anders Gudmundsson (Lund University, Sweden), Jan-Åke Nilsson (Lund University, Sweden), Caroline Isaksson (Lund University, Sweden)

ann-kathrin.ziegler@biol.lu.se

Anthropogenic change exposes wildlife to many pollutants, among which air pollutants, such as tropospheric ozone, are potent prooxidants. Human activity also includes several other implications for wildlife, e.g., changed food availability and distribution of pathogens in cities. These covarying stressors may interact, thereby modulating the physiological responses and costs related to anthropogenic change. For instance, many anthropogenic food items contain relatively more ω6- than ω3- polyunsaturated fatty acids (PUFAs). Metabolites derived from ω6-PUFAs are considered pro-inflammatory and oxidative stress enhancing, whereas the opposite response is linked to ω3-derived metabolites. We hypothesised that differential intake of ω6- and ω3-PUFAs modulates the oxidative stress state of birds and thereby affects the responses towards pro-oxidants. We manipulated dietary ω6:ω3-ratios and ozone levels in a full-factorial design using captive zebra finches (Taeniopygia guttata). Additionally, we simulated an infection, thereby also the immune system’s adaptive oxidative burst, by injecting lipopolysaccharide. In ambient air conditions, ω3-diet birds had a potentially higher susceptibility to pro-oxidants than ω6-diet birds, indicated by a lower antioxidant ratio. However, when exposed to ozone, the diet effect disappeared. Instead, ozone-exposure overall reduced the total concentration of glutathione. Moreover, ω6-diet birds had overall higher antioxidant capacity compared to ω3-diet birds. Interestingly, only immune challenge increased oxidative damage, suggesting the oxidative burst of the immune system overrides the other pro-oxidative processes. Our results show that ozone, dietary PUFAs, and infection all affect the redox-system, but in different ways, suggesting that the underlying responses are de-coupled despite that they all increase pro-oxidant exposure or generation.

A13.18 EVOLUTIONARY OPTIMIZATION OF CADMIUM DETOXIFICATION BY

METALLOTHIONEIN DOMAIN DUPLICATION(S) IN GASTROPODSS

Tuesday 4 July 2023 16:45

Veronika Pedrini-Martha (University of Innsbruck Department of Zoology, Austria), Michael Niederwanger (University of Innsbruck Department of Zoology, Austria), Reinhard Dallinger (University of Innsbruck Department of Zoology, Austria)

veronika.pedrini-martha@uibk.ac.at

The inactivation of toxic metal ions like Cadmium (Cd2+ ) has been an important evolutionary achievement that fostered adaptation of gastropod lineages to differently Cd-exposed habitats. In particular, the expression of small cysteine-rich, metal-responsive Metallothioneins (MTs) is a major mechanism involved in Cd binding and detoxification.

Most MTs consist of an N- and C-terminal domain linked together by a short hinge region. Recently we have discovered unusually largesized multi-domain MTs (md-MTs), with up to ten concatenated metal-binding domains, each of them capable of binding three Cd2+ equivalents per domain.

By sequence screening of multiple snail species, we detected such md-MTs in marine Neomphalina, terrestrial Heterobranchia and in freshwater Caenogastropoda. The emergence of these additional domains within MTs contributes to the optimization of Cd-binding efficiency in snails by increasing their Cd-binding stoichiometry. To proof the involvement of md-MTs in Cd detoxification of the freshwater snail Marisa cornuarietis, Cd exposure experiments were conducted. This species possesses two MT’s. The short MT-isoform (MT1) consists of one truncated and one full-length N-terminal domain linked to a well-structured C-terminal domain. The second MT possesses eight domains (8d-MT), altogether with a binding stoichiometry of 24 Cd2+ equivalents per single MT molecule. Upon metal exposure, the MT1 gene lacked Cd-responsiveness at all. In contrast, 8d-MT gene transcription was significantly upregulated by Cd exposure, proofing its involvement in Cd detoxification.

A13.19 REPLICANT - GENERATING TRAINING DATA TO AUTOMATE ANIMAL BEHAVIOURAL RESEARCH

Wednesday 5 July 2023 09:00

Fabian Plum (Imperial College London, United Kingdom), Rene Bulla (The Pocket Dimension, Germany), Hendrik Beck (Imperial College London, United Kingdom), Natalie Imirzian (Imperial College London, United Kingdom), David Labonte (Imperial College London, United Kingdom)

fabian.plum18@imperial.ac.uk

Deep learning-based computer vision methods are transforming research on animal behaviour, where they promise to reduce time costs, increase statistical power, and minimise potential for human bias. Their successful application in ethology and its intersection with neuroscience, morphology, locomotion, and conservation is closely tied to the need for complex annotated training data. Unfortunately, datasets of a size and quality required to achieve robust inference are rarely available and the effort required to curate them may outweigh the immediate benefit of the enabled automation. Transfer-learning in applications such as multi-animal tracking and pose-estimation has enabled work in non-model species, but still requires time intensive hand-annotation of example footage, and is only performant in well-defined and constrained conditions. Here we introduce replicAnt, a configurable pipeline implemented in Unreal Engine 5 and Python, designed to generate large and highly variable datasets with a few mouse clicks. replicAnt places 3D models of animals in procedurally generated environments, from which automatically annotated images can be exported. We demonstrate that such synthetic data can significantly reduce the hand-annotation required to achieve benchmark performance in common applications such as animal detection, tracking, pose estimation, semantic- and instance segmentation. Ultimately, it increases the subject-specificity and enables the application of the trained networks in changing environments, so conferring robustness. In some applications, replicAnt may even remove the need for hand-annotation altogether, further decreasing time-costs, and presenting a significant step towards porting deep learning-based computer vision tools to the field.

A13.20 THE HUNTING STRATEGIES OF BILLFISHES FEEDING ON SMALL SCHOOLING FISH

Wednesday 5 July 2023 09:00

Paolo Domenici (CNR IBFIAS, Italy)

paolo.domenici@cnr.it

During predator-prey encounters, a high locomotor performance in unsteady manoeuvres (i.e. acceleration and turning) is desirable for both predators and prey. While speed increases with size in fish and other aquatic vertebrates in terms of continuous swimming, most unsteady locomotor performance variables decrease with size. The scaling of unsteady locomotor performance makes it potentially difficult for large aquatic vertebrates to capture elusive prey by using whole-body attacks, since the overall manoeuvrability and acceleration of small prey is likely to be superior to that of large predators. Using examples (i.e. videos) from field work carried out on group-hunting billfishes (striped marlin and sailfish) attacking schooling fish, I will discuss how the feeding strategies of these predators may involve the use of weapons as well as stealth, in order to compensate for their lower unsteady swimming performance when compared to their prey. The hunting strategies of these predators will be discussed within the context of scaling of unsteady swimming performance.

A13.21 FACING THE GREEN THREAT: A WATER FLEA’S DEFENSES AGAINST A CARNIVOROUS PLANT

Wednesday 5 July 2023 09:30

Sebastian Kruppert (Albert-Ludwigs-Universität Freiburg, Germany), Martin Horstmann (Ruhr-Universität Bochum, Germany), Linda C. Weiss (Ruhr-Universität Bochum, Germany), Elena Konopka (Ruhr-Universität Bochum, Germany), Nadja Kubitza (Ruhr-Universität Bochum, Germany), Simon Poppinga (Technische Universität Darmstadt, Germany), Anna S. Westermeier (Albert-LudwigsUniversität Freiburg, Germany), Thomas Speck (AlbertLudwigs-Universität Freiburg, Germany), Ralph Tollrian (Ruhr-Universität Bochum, Germany)

sebastian.kruppert@biologie.uni-freiburg.de

Every ecosystem shows multiple levels of species interactions, which are often difficult to isolate and to classify regarding their specific nature. For most of the observed interactions, it comes down to either competition or consumption. The modes of consumption are various and defined by the nature of the consumed organism, e.g., carnivory, herbivory, as well as the extent of the consumption, e.g., grazing, parasitism. While the majority of consumers are animals, carnivorous plants can also pose a threat to arthropods. Water fleas of the family Daphniidae are keystone species in many lentic ecosystems. As most abundant filter feeders, they link the primary production to higher trophic levels. As a response to the high predatory pressures, water fleas have evolved various inducible defences against animal predators. Here we show the first example, to our knowledge, in Ceriodaphnia dubia of such inducible defences of an animal against a coexisting plant predator, i.e., the carnivorous bladderwort (Utricularia x neglecta Lehm, Lentibulariaceae). When the bladderwort

is present, C. dubia shows changes in morphology, life history and behaviour. While the morphological and behavioural adaptations improve C. dubia’s survival rate in the presence of this predator, the life-history parameters likely reflect trade-offs for the defence.

Article DOI: 10.3390/ijms23126474

A13.22 SHINE BRIGHT LIKE A CANNIBAL: FEEDING ON CONSPECIFIC TADPOLES IMPACTS THE QUALITY OF WARNING SIGNALS IN AN APOSEMATIC FROG

Wednesday 5 July 2023 09:45

Bibiana Rojas (University of Veterinary Medicine Vienna, Austria), Chloe A Fouilloux (University of Jyväskylä, Finland), Janne K Valkonen (University of Jyväskylä, Finland)

bibiana.rojas@vetmeduni.ac.at

The benefits of cannibalism have often been a matter of debate in developmental and evolutionary biology, as they can be difficult to quantify. In species with complex life cycles, the carry-over effects of larval diet are inextricably linked to the fitness of individuals in adulthood. In this study, we measured how larval cannibalism impacts key life history and phenotypic traits of the aposematic frog, Dendrobates tinctorius. Adults of this species have bright dorsal colour patterns (warning signals) consisting of yellow dorsal markings on a black background, which are subject to enormous interindividual variation. Here, we sought to disentangle the benefits and costs of cannibalism on development (growth rate, age and size at metamorphosis) and phenotype (warning signal quality) by rearing tadpoles with a high-protein diet that consisted of either a supplement of fish, a recently sacrificed tadpole (scavenging), or active cannibalism (kill and consume). Rather surprisingly, we found no obvious advantages of cannibalism in terms of life history traits, as cannibals did not metamorphose larger or faster than tadpoles from other treatments. However, we found an interesting tradeoff whereby cannibalistic tadpoles tended to metamorphose with a smaller, yet brighter warning signal. These findings hint at a potential positive carry-over effect of cannibalism on the efficacy of warning signals, which could have indirect effects on survival upon metamorphosis, when froglets start facing the dangers of terrestrial life.

A13.23 LINKING HEALTH ASSESSMENTS, BODY CONDITION, AND STRESS TO

Wednesday 5 July 2023 10:00

Courtney R Shuert (Fisheries and Oceans Canada, Canada), Marie Auger-Méthé (University of British Columbia, Canada), Nigel Hussey (University of Windsor, Canada), Karine Béland (Montréal Space for Life, Canada), Marianne Marcoux (Fisheries and Oceans Canada, Canada)

cshuert@gmail.com

Monitoring population health has become increasingly important as the compounding and accelerating effects of climate change will continue to stress species residing in the Arctic. High-resolution telemetry data provide extensive detail of the movements of individuals and advanced modelling techniques like Hidden Markov Models (HMM) are becoming increasingly popular to characterize behaviour using movement data. However, studies to date have inferred changes in physiological parameters from movement behaviour, and the continuous collection of physiological data in the field is still in its infancy, leading to a disconnect between information on the internal state of the animal and its outward behaviour. Here, we aimed to link measured health and stress data to movement behaviour using narwhal as a case study. Health and stress data were gathered from narwhal (n= 24) captured in Nunavut, Canada as part of a larger study to understand the movement ecology of the species. Individual adult narwhal were equipped with satellite transmitters and/or highresolution biologgers, which provided metrics of movement from location data, dive behaviour, and fine-scale acceleration. We present our findings of incorporating health assessments, body condition, and stress hormones into HMMs to understand changes in both the mechanics of behaviour (emission probabilities) and activity budget decisioning (transition probabilities) derived from animal-borne biologging devices, highlighting the importance of using internal state to inform modelling. Understanding how internal state and stress manifests in changes to movement ecology will serve as a useful baseline for conservation practitioners and in developing a toolkit for long-term community-based monitoring programs.

-45°

A13.24 NUTRITIONAL STATE AFFECTS PARENTAL COOPERATION IN A BURYING BEETLE

Wednesday 5 July 2023 10:15

Georgia A Lambert (University of Edinburgh, United Kingdom),

Per T Smiseth (University of Edinburgh, United Kingdom)

G.A.Lambert@sms.ed.ac.uk

In species that provide biparental care, there is sexual conflict between parents over how much each should contribute towards caring for their joint offspring. Theoretical models for the resolution of this conflict mediated through behavioural negotiation between the two parents assume that parents cannot assess their partner’s state directly but do so indirectly by monitoring their partner's contribution. Here, we test whether parents can assess their partner’s state directly by investigating the effect of nutritional state on cooperation between parents in the burying beetle Nicrophorus vespilloides. We used a two-by-two factorial design, in which a well-fed or food-deprived male was paired with a well-fed or food-deprived female. We found that females adjusted their level of care both to their own nutritional state and to that of their partner and that these decisions were independent of their partner’s contribution. We found no evidence that males responded directly to nutritional state. Males instead responded indirectly based on the contribution of their partner. Our results suggest that parents are able to assess the state of their partner, in contrast to what was assumed, and that these assessments play an important role in the mediation of sexual conflict between caring parents.

MOVEMENT ECOLOGY IN NARWHAL.

A13.25 THE ROLE OF SOCIAL ENVIRONMENT AND METABOLISM IN DETERMINING GROWTH

PERFORMANCE

OF A TEMPERATE FISH

Wednesday 5 July 2023 11:00

Elizabeth Hoots (Deakin University, Australia), Timothy D Clark (Deakin University, Australia)

beth.hoots@research.deakin.edu.au

Some fish grow faster than their conspecifics, even when their life stage, habitat, and feeding conditions are identical. This study investigated potential causes of inter-individual variability in growth performance forGalaxias maculatus, a diadromous fish species prolific throughout the southern hemisphere.

We tagged 35 wild-caught, similarly sized, pre-reproductive fish for individual-level identification, and collected mass and length measurements every 8-10 weeks for 9 months to track growth performance over time. After reviewing the first growth performance measurements, we isolated the initially fastest (n=5) and slowest (n=5) growing individuals to see whether social dynamics in the original tanks played a role in determining the growth performance of these individuals. Specifically, we looked for signs of compensatory growth in the slow-growing fish, and the emergence of a new hierarchy among the fast-growers. Meanwhile, we measured the maximum and standard metabolic rates of each fish in 18-hour respirometry trials to see if growth could be explained by metabolic traits. Finally, we recorded videos of each tank at feeding time to watch for signs of aggression.

Analyses suggest that fast-growing fish are not more outwardly aggressive than slow-growers, and there is no clear metabolic signature to explain growth profiles. As aquatic habitats change, so too will the phenotypes favored in those habitats. Populations with high intraspecific variability in growth performance may be better suited genetically to respond to climate change. The results of this study give insights into both the present and future growth performance of an ecologically and economically important aquatic ectotherm.

A13.26 INTERINDIVIDUAL BEHAVIOURAL VARIATION IN RESPONSE TO ELEVATED CO2 PREDICTS MRNA TRANSCRIPT

ABUNDANCE OF GENES RELATED TO ACID-BASE REGULATION IN MEDAKA

Wednesday 5 July 2023 11:00

Caleb T Hasler (The University of Winnipeg, Canada), Jenna Fleet (The University of Winnipeg, Canada), Theresa Mackey (University of Manitoba, Canada), Jennifer D Jeffrey (The University of Winnipeg, Canada), Sara Good (The University of Winnipeg, Canada), Ken M Jefferies (The University of Manitoba, Canada)

c.hasler@uwinnipeg.ca

Rising carbon dioxide (CO2) in aquatic ecosystems due to climate change is a challenge for aquatic ecotherms. Interindividual variation (i.e., phenotypic plasticity) should permit individuals within a population to respond to a reasonably predictable change in their environment; we

examined whether interindividual variation in behavioural responses to CO2 could predict how fish would respond to elevated CO2 for multiple phenotypic and molecular traits. To this end, we used behavioural variation to phenotype freshwater teleost exposed to acute elevated CO2, and used this to assign individuals as either high or low responders. Subsequently, we exposed both high and low responders to elevated CO2 for 6 weeks and quantified the effect on body condition, reproduction, behaviour, and mRNA transcript responses of brain, gill, and liver genes associated with relevant physiological processes. Generally, we found few relationships between the phenotypic groups and body condition, reproduction and behaviour following the exposure period; however, stark differences in gene transcripts from each tissue related to various processes were found. The differences in gene transcript abundance were mostly related to the behavioural phenotype group assignment, and not to the CO2 treatment, or the interaction between CO2 treatment and the phenotype group. The most pronounced changes were in the gill transcripts related to acid-base regulation, suggesting that the observed behavioural variation used to assign fish to phenotypic groups may have an underlying molecular origin.

A13.27 VARIABILITY IN VARIABILITY: HOW DOES INTER-INDIVIDUAL TRAIT VARIATION DIFFER BETWEEN MEN AND WOMEN?

Wednesday 5 July 2023 11:30

Lewis Halsey (University of Roehampton, United Kingdom), Vincent Careau (University of Ottawa, Canada), Eimear Dolan (Universidade de São Paulo, Brazil), Gabriel Esteves (Universidade de São Paulo, Brazil), John Speakman (University of Aberdeen Chinese Academy of Sciences, China)

l.halsey@roehampton.ac.uk

Like other animals, individual human beings vary from one another in every characteristic imaginable – an obvious yet endlessly intriguing aspect of the human condition. Many practitioners consider interindividual variation between females to be greater than between males, which has encouraged a sex bias in health and medical research resulting in unnecessary knowledge gaps with important clinical implications. Yet in another field - evolutionary biology - the received wisdom is thatmalesare the more variable sex, possibly due to male heterogamety. Through two studies, we sought clarity on the contentious and sometimes controversial issue of the degree of evolved sex differences in terms of inter-individual variation. We first analysed the IAEA DLW database on energy expenditure in adult humans. Even when statistically comparing men and women of the same age, height, and body composition, there is much more variation in energy expenditure between males. Greater male variation (GMV) in both total and activity energy expenditure can be explained by GMV in levels of daily activity. The large GMV in basal metabolic rate is remarkable. We argue, with support from the literature, that it may be explained by GMV in the size of energy-demanding organs. In contrast, we then analysed a dataset of 50 morphological and physiological characteristics (NHANES), and observed substantially more traits exhibiting greater female variation (GFV) than GMV. This ratio was close to balanced, however, when the analysis excluded post-menopausal women, suggesting that the oestrus cycle affecting labile traits partially drives GFV. We discuss the clinical implications.

A13.28 RE-EVALUATING THE EVIDENCE FOR ADAPTIVE TRANSGENERATIONAL PLASTICITY

Wednesday 5 July 2023 11:45

Hayley Cameron (Monash University, Australia), Dustin J. Marshall (Monash University, Australia)

hayley.cameron@monash.edu

Adaptive transgenerational plasticity occurs when parents alter the phenotype of their offspring in response to environmental cues to maintain offspring fitness and minimise the negative impacts of environmental changes. Yet the prevalence, strength and nature of adaptive transgenerational plasticity remain unclear, and are fiercely debated. Previous meta-analyses aimed at evaluating the evidence for transgenerational plasticity yield different conclusions and there are multiple, competing ways in which transgenerational plasticity has been defined and measured. Here, we apply a new analytical framework for measuring and understanding transgenerational plasticity. We borrow analytical approaches from studies of local adaptation and using a meta-analytical approach across animals and plants, we show that transgenerational plasticity is both more common, and more complicated, than has been previously appreciated.

A13.29 PATERNAL CARE BUFFERS AGAINST THE COST OF INTERSPECIFIC COMPETITION IN NICROPHORUS VESPILLOIDES

Wednesday 5 July 2023 12:00

Casey Patmore (University of Edinburgh Institute of Ecology and Evolution, United Kingdom), Alexandra Vavrik (University of Edinburgh Institute of Ecology and Evolution, United Kingdom), Per T Smiseth (University of Edinburgh Institute of Ecology and Evolution, United Kingdom)

c.patmore@sms.ed.ac.uk

Competition over limited resources is costly and thought to improve cooperation between parents, as parents working together are better equipped to deal with challenges than an individual working alone. The burying beetle Nicrophorus vespilloides is an insect that displays biparental care, with parents breeding on small vertebrate carcasses and caring for their shared offspring. However, the carcasses they depend on represent a rare and valuable resource that is sought out by many other species. We hypothesise that the presence of carcass rivals, such as the bluebottle fly Calliphora vomitoria, will influence the care and cooperative behaviours displayed by N. vespilloides – as increased cooperation becomes beneficial under the stress of interspecific competition. We measured the egg-laying behaviours of female burying beetles rearing their offspring in the presence of flies, either as a lone parent or together with their male partner. We found that the absence of a male partner delays egg-laying and reduces hatching success, and that larval survival is highest in the presence of both males and flies. Our results indicate that the presence of a partner can buffer against the cost of interspecific competition, which may therefore be an important driver behind increased social and cooperative behaviours.

A13.30 THE ONTOGENY OF PERCHING FLIGHT IN ZEBRA FINCHES

Wednesday 5 July 2023

12:15

Emma L Borsier (University of Oxford, United Kingdom), Graham K Taylor (University of Oxford, United Kingdom)

emma.borsier@biology.ox.ac.uk

Flight is the most complex form of locomotion found in the animal kingdom, as it requires considerable motor control and energy. Birds can be highly agile and skilled flyers but, despite recent technology advances allowing high-resolution tracking of birds during flight, how they acquire these flight behaviours remains poorly understood. In particular, few studies have investigated whether learning is necessary to acquire complex flight skills or whether they are a result of maturation.

We investigate the ontogeny of perching flight, defined as the ability to land safely on perches, which is a high-risk behaviour that many birds need to acquire early in life. Using a target perch fit with a force balance sensor and a motion capture system, we captured landing flights in juvenile zebra finches from their first day out of the nest (c. 18 days old) until they had reached adulthood (100 days old). We find that zebra finches initially adopt a slow but careful strategy, with a downward approach, then progressively switch to a faster and more efficient strategy, with a more horizontal and direct approach toward the perch. Our results suggest that birds learn complex flight skills such as perching through practice during the fledgling period.

A13.31 BARN SWALLOWS LEARN BUT FORGET HOW THEIR EGGS LOOK LIKE

Wednesday 5 July 2023 15:00

Michal Šulc (Institute of Vertebrate Biology Czech Academy of Science, Czech Republic), Lisandrina Mari (Institute of Vertebrate Biology Czech Academy of Science, Czech Republic), Anna E. Hughes (Department of Psychology University of Essex, United Kingdom), Oldřich Tomášek (Institute of Vertebrate Biology Czech Academy of Science, Czech Republic), Tomáš Albrecht (Institute of Vertebrate Biology Czech Academy of Science, Czech Republic), Václav Jelínek (Institute of Vertebrate Biology Czech Academy of Science, Czech Republic)

sulc-michal@seznam.cz

Learning and remembering are key to the survival and reproduction of animals. It has been shown that birds benefit from knowing the appearance of their own eggs. This seems to be especially important for hosts of brood parasites that use this knowledge to recognize and reject differently looking parasitic eggs. Here, we investigated whether the knowledge of egg appearance is innate or learnt following egg laying. The barn swallow (Hirundo rustica) is a perfect model species because 1) it is a conspecific brood parasite capable of ejecting differently looking eggs and 2) in our ringed study population we are able to distinguish between naïve first-time breeders that never saw their eggs and experienced females. We experimentally inserted an artificial mimetic egg (ME) or non-mimetic blue egg (NME) into swallow nests before they laid their own eggs and observed their response (acceptance or rejection). We found that experienced females ejected NME more often than ME compared to naïve females that ejected both egg types in a similar and lower rate. This suggests that birds do not

have innate template image of their eggs but learnit through breeding experience. Moreover, we found that this acquired template may not be permanent and returning birds reinforce it with every first nesting of the breeding season. Our results help to better understand the process by which birds learn to recognize their own eggs and bring new insights into the birds' ability to learn and remember important visual cues.

A13.32 ROLE OF BIOGENIC AMINES SEROTONIN AND DOPAMINE IN ANXIETYLIKE BEHAVIOUR OF CRAYFISH (ASTACUS LEPTODACTYLUS)

Wednesday 5 July 2023 15:00

Areeba Khan (University of Hull, United Kingdom), Thomas Breithaupt (University of Hull, United Kingdom)

AREEBA.KHAN-2020@hull.ac.uk

Biogenic amines are widely known to influence behaviour among invertebrates. In this study, we analysed the role of two biogenic amines, serotonin (5-HT) and dopamine (DA) in crayfish’s anxiety-like behaviour (ALB). Previous studies have indicated the involvement of 5-HT in ALB but the role of DA is still unclear. We analysed behaviour in a plus-maze arena having light (70lux) and dark (10lux) zones. We used time spent and active speed in the two zones as behavioural indicators. We expected animals displaying ALB to spend more time and reduced movement in the dark zones. 5-HT injection triggered ALB at the two concentrations tested (1µM and 10µM) while dopamine appeared to have a dose-dependent effect with only 10µM concentration leading to ALB. The anxiogenic effect of 5-HT and 10µM DA disappeared when administered together with either 5-HT1 receptor antagonists (50µM maleate salt) or the non-specific DA blocker (10µM methergine) suggesting that a parallel pathway could be involved in 5-HT and DA activation. Surprisingly, co-injection of 1µM DA with DA blockers led to ALB rather than to the bold behaviour displayed in all other blocker administrations. In contrast, co-administration of 1µM DA with 5-HT1 blocker did not have an effect which could be a result of different receptor sites being responsive in the pathway. Overall, our results emphasize the involvement of a complex functional interplay among biogenic amines in anxiety-like behaviour in crayfish with blockers showing effects on more than one biogenic amine.

A13.33 FISHY BEHAVIOUR IN FISH ECOLOGY

Wednesday 5 July 2023 15:30

Fredrik Jutfelt (Fredrik Jutfelt, Norway), Josefin Sundin (SLU, Sweden), Jeff Clements (Fisheries and Oceans, Canada), Zara Cowan (NTNU, Norway), Timothy Clark (Deakin, Australia)

fredrik.jutfelt@ntnu.no

Research on the impacts of microplastics and that of ocean acidification on fish may seem like disconnected fields but there are some surprising connections. Both topics have been published in high-impact journals and both appear to be partly based on fabricated data. The research also has its roots in the same Australian fish ecology lab. What evidence of data fabrication has been found? Is anything being done about it? What should we do

to fix science? In this talk, I describe my journey from a naïve and trusting scientist to an old and cynical professor who rants about scientific misconduct.

A13.34 SIZE-SELECTIVELY HARVESTED POPULATIONS RECOVER PHENOTYPICALLY, NOT GENETICALLY

Wednesday 5 July 2023 15:45

Silva Uusi-Heikkilä (University of Jyväskylä, Finland), Daniel Sadler (University of Jyväskylä, Finland), Stephan Van Dijk (University of Jyväskylä, Finland), Tiina Sävilammi (University of Jyväskylä, Finland), Phillip Watts (University of Jyväskylä, Finland)

silva.k.uusi-heikkila@jyu.fi

Fisheries remove enormous amounts of fish and typically target the largest individuals in a stock, thus generate strong directional selection favoring small body size. After fisheries have reduced the population size and average individual body size to a level, where fishing is no longer profitable, fishing is typically stopped, and populations are allowed to recover. However, the past fisheries selection has likely reduced phenotypic and genetic variation and the recovered fish populations might be sensitive to new selection pressures and environmental stressors. We use experimentally harvested and recovered fish populations to study the effects of harvesting and whether the harvest-induced differences among the selection lines erode during the recovery. Five generations of fisheries selection (selection favoring small body size) induced large-scale phenotypic and genetic changes in experimental fish populations. After ten generations of recovery (no harvesting) populations under fisheries selection had recovered at the phenotypic level but remained genetically different from the control fish (non-size-selectively harvested). Using whole-genome sequencing we showed that small- and large-selected lines became more similar to each other while the control fish further diverged. Interestingly, genetic variation did not decrease during the harvesting or the recovery period. Our results show that while fish populations show a sign of recovery at the phenotypic level, they might still not recover at the genotype level. This could have serious effects on populations’ adaptive potential and negatively affect their resilience to new selection pressures, such as environmental changes or re-harvesting.

A13.35 FISHERIES-INDUCED CHANGES RECOVER SLOWLY BUT SURELY OVER TIME.

Wednesday 5 July 2023 16:00

Stephan N Van Dijk (University of Jyväskylä, Finland), Daniel E Sadler (University of Jyväskylä, Finland), Phillip C Watts (University of Jyväskylä, Finland), Silva Uusi-Heikkilä (University of Jyväskylä, Finland)

vandijkz@jyu.fi

Overfishing is one of the greatest threats to fish populations. Sizeselective harvesting favours small adult body size typically accompanied

with fast juvenile growth, early maturation, smaller body size at maturation and low reproductive output. These changes might be slow to recover and ultimately drastically reduce a population growth and survival. To study the recovery potential of exploited experimental populations, we compared life-history traits in three differently sizeselected experimental zebrafish lines (small-selected, which mimics selection typical for fisheries, large-selected and randomly-selected) after five generations of harvesting and ten subsequent generations of recovery.

Five generations of size-selective harvesting led to decreased average body size and low reproductive output among small-selected fish compared to the other selection lines. Previous studies have demonstrated significant gene expression and sequence level changes among the selection lines. We further explored the epigenetic changes caused by size-selective harvesting and show clear differences in methylation patterns among the selection lines. Despite the genetic changes after five generations of harvesting, we show that after a recovery period (which was twice as long as the harvesting period), the phenotypic differences in adult body size among the selection lines had eroded, as well as the differences in fecudity. Our experimental results demonstrate that size-selective harvesting can cause contemporary phenotypic and genetic changes in exploited fish populations, but that these changes can be reversible if populations are allowed to recover long enough.

of groups and individual ornamental fish. These findings show how, even if fish survive after CR, there are consequences. This highlights how ornamental fishing, at least in the short-term, is not only impacting the preferred marketing species but has a wider ecosystem impact via effects on non-target species.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A13.37 FISH GILLS AS AN IN VIVO DETECTION PLATFORM FOR STUDYING ACID-EXCRETING MECHANISMS

Wednesday 5 July 2023 POSTER SESSION

A13.36 CATCH-AND-RELEASE

NETTING AFFECTS SOCIAL BEHAVIOUR IN THE THREE-STRIPED DWARF CICHLID (APISTOGRAMMA TRIFASCIATA)

Wednesday 5 July 2023 16:15

Zoe Storm (University of Glasgow School of Biodiversity

One Health and Veterinary Medicine, United Kingdom), Emmanuelle Chrétien (Université de Montréal Département de sciences biologiques, Canada), Oluwaseun Ojelade (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom), Daphne Cortese (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom), Amelia A Munson (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom), Shaun S Killen (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom)

zoectstorm@gmail.com

Catch-and-Release (CR) fishing is widespread in commercial fisheries and angling, but little is known about indirect effects associated to CR, including behavioural and physiological effects. Effects of CR fishing have been entirely overlooked in the ornamental fishing industry, where catching and marketing fish for their exotic characteristics and beauty leads to release of species and individuals with non-preferred characteristics. In the laboratory, we investigated the effects of CR netting on dominance hierarchies and social interactions of threestriped dwarf cichlid (Apistogramma trifasciata), a regularly caught and released ornamental fish. Fish were kept in groups of four, then observed for social interactions and foraging behaviour at three time points: before a CR disturbance, immediately after, then 24 hours after the disturbance. Preliminary results show effects of CR netting on dominance hierarchy steepness and agonistic interactions, although fish seemed to have somewhat recovered 24h after the disturbance. We found less evidence for effects on foraging behaviour. Our study therefore suggests short-term impacts of CR netting on social behaviour

Shang-Wu Shih (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Ming-Yi Chou (Department of Life Science National Taiwan University, Taiwan), PungPung Hwang (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

frank4xx36@gmail.com

The gills (rather than the kidney) containing ionocytes are the most important ionoregulatory organs in adult teleosts. In terms of transporter expression and functions, teleost ionocytes are analogous to tubular epithelial cells in mammalian kidneys. However, it is not accessible to physiological detections with an electrode in the gills covered by the opercula or the kidneys of a living animal. That is, direct evidence on in vivo physiological analyses is severely lacking in both fish gills and mammalian kidneys. Here, the present study aims to apply an electrophysiological tool, scanning ion-selective electrode technique (SIET), to adult zebrafish gills and investigate branchial acid-excreting functions and mechanisms in vivo. First, we carefully cut and removed the opercula from zebrafish in a certain proportion to ensure a high survival rate and physiological state. Zebrafish were then subjected to a 7-day acid exposure to trigger the pathway of acid excretion in the gills, including up-regulation of related transporters/ enzymes and differentiation of a specific ionocyte subtype for acid excretion. By using SIET, we proved that the H+ and ammonia excretion capacities were enhanced in the gills after a 7-day acid exposure and these excreting functions is via H+ -ATPase and Na+ /H+ exchanger. Moreover, we also explored a novel transporter, SLC26a11, in zebrafish gills by single-cell RNA sequencing and analyzed its function by SIET detection combined with vivo-morpholino treatments or environmental challenges. Overall, our study established an effective method for in vivo detection in fish gills, which may serve as a surrogate system to explore renal physiology.

A13.38 UNCOVERING THE PRIMATE CLITORIS WITH ADVANCED IMAGING TECHNIQUES

Daniel Varajão de Latorre (Manchester Metropolitan University, United Kingdom), Magdalena Muchlinski (Oregon Health Science Univeristy, United States), William Sellers (University of Manchester, United Kingdom), Georg Hantke (National Museums Scotland, United Kingdom), Andrew Kitchener (National Museums Scotland, United Kingdom), Charlotte Brassey (Manchester Metropolitan University, United Kingdom)

d.varajao.de.latorre@mmu.ac.uk

Detailed descriptions of the human clitoris, from the last 20 years, have revealed that over 90% of clitoral tissue is internal and just the small clitoral glans is external. In non-human primates the external morphology of the clitoris varies across species, for example, in female spider-monkeys it is long and has been associated with chemical communication with males, and ring-tailed lemurs’ clitoris has been described as “masculinized” because it is elongated and tunneled by the urethra. However, the internal clitoral anatomy and its relationship with social systems or mating behaviours remains unknown. The internal structure of the clitoris is difficult to access, making it challenging to image and study its anatomical structure. Here, we establish protocols that allow us to study the full primate clitoris from deceased zoo specimens, frozen prior to study. We combine specimen dissection (for gross anatomy and histology) with advanced imaging techniques, specifically Magnetic Resonance Imaging (MRI) and diffusible iodine contrast-enhanced Computer Tomography (diceCT). While MRI can reveal the clitoris in living human participants, its applicability for studying the clitoris from previously frozen cadavers had never been tested. Comparatively, diceCT offers more resolution than MRI for studying soft tissue but involves variable staining times that depend on the diffusion of iodine into the tissue of interest. This technique had never been used to image the clitoris of primates. After determining the protocols for iodine staining, we compare the images generated from these two techniques and make recommendations for studying the different portions of the internal clitoris.

involved in regulating epithelial H+ secretion in marine fish exposed to OA. Our analysis showed that expression of one particular oxytocin receptor,OXTRb, were upregulated in marine medaka exposed to OArelevant hypercapnia. Knockdown of OXTRb impaired both basal and hypercapnia-induced H+ secretion in the yolk-sac skin, which was accompanied by a reduction in cAMP level, suggesting that OXTRb may act via cAMP signaling. We also found that a transmembraneassociated adenylyl cyclase, ADCY5, was upregulated under hypercapnia and co-expressed with OXTRb in ionocytes, suggesting that oxytocinmediated mechanisms of acid-base regulation may involve ADCY5. These findings shed light on an endocrine mechanism by which marine teleosts may adapt physiologically to climate change.

A13.40 THE PHYSIOLOGICAL IMPACT ON METABOLIC PERFORMANCE FOR TRINIDAD GUPPIES (POECILIA RETICULATA) EXPOSED TO HYPOXIA

Wednesday 5 July 2023

POSTER SESSION

Malin Fløysand (University of Bergen, Norway), Elise Doddema (University of Bergen, Norway), Andrea Campos-Candela (University of Bergen, Norway), Rachael Morgan (University of Bergen, Norway)

mfl019@uib.no

Wednesday 5 July 2023 POSTER SESSION

Ying-Jey Guh (Institute of Cellular and Organism Biology

Academia Sinica, Taiwan), Yi-An Chen (Department of Life Science National Taiwan University, Taiwan), Tzu-Yen Liu (Institute of Oceanography National Taiwan University, Taiwan), Yung-Che Tseng (Institute of Cellular and Organism Biology Academia Sinica, Taiwan)

yingjeyguh@gmail.com

The ocean acidification (OA) caused by increased atmospheric CO2 is a significant aspect of global climate change. Fish have a defense mechanism against this pH disturbance, which involves increasing their blood bicarbonate buffering and stimulating H+ secretion in ion-regulatory epithelial tissues when exposed to hypercapnia. While the endocrine system regulates acid-base balance in various vertebrate species, hormonal control of acid-base adjustment in marine fish in response to acidified seawater has not been extensively studied. To fill this gap, we studied marine medaka as a model and identified oxytocin, a neurohypophysial hormone, as a prominent factor

Tropical fishes are known for being diverse, but what factor plays a role in creating such diversity? In tropical systems at night, algae use oxygen, and with the combination of densely populated aquatic environments, this will create a daily hypoxia build-up (~20-40%). While this has been known for a while, more research is needed to understand how daily hypoxia affects different physiological responses. By studying the metabolic performance of fish exposed to daily hypoxia, we can assess whether tropical fish are adapted to this. This will be a first step into understanding how the physiological response might impair a trade-off with other life-history traits, such as growth rate. In this study, we used the Trinidad guppies (Poecilia reticulata), with 96 individuals across 12 aquariums, half acclimated to daily hypoxia fluctuations and the other half to normoxia. After acclimation, the fish underwent intermittent-flow-through respirometry for 22 hours to measure ṀO2min and ṀO2max under both normoxia and hypoxia conditions, mimicking the daily fluctuating oxygen levels. Since we believe that tropical fish are adapted to fluctuating hypoxia, we predict that the guppies acclimated to hypoxia will perform better when exposed to these conditions.

A13.41 WHAT DIFFERENCE DOES 500 YEARS MAKE? EXPLORING THE METABOLOMIC SIGNATURE OF EXTREME LONGEVITIES IN BIVALVES.

Wednesday 5 July 2023 POSTER SESSION

Pauline Bertrand (Université du Québec à Rimouski, Canada), Hélène Lemieux (University of Alberta, Canada), Véronique Desrosiers (Université du Québec à Rimouski, Canada), Enrique Rodriguez (University College London, United Kingdom), Pierre U Blier (Université du Québec à Rimouski, Canada)

A13.39 OXYTOCIN SIGNALING IS REQUIRED FOR ENHANCED H+ SECRETION UNDER OCEAN ACIDIFICATION IN MARINE MEDAKA

pauline.bertrand@uqar.ca

Longevity in the animal kingdom is unfair. Within the bivalve class, the ocean quahog Arctica islandica can live more than 500 years, while its cousin the freshwater clam Corbicula fluminea only lives 4 years. What physiological processes are at the origin of these inequalities among species? The role of mitochondrial structure and function in dictating the rate of aging has been under scrutiny over the past decades. Indeed, comparative studies on bivalves revealed differences in the control of mitochondrial respiration related to lifespan, showing longer-lived species have stronger electron flux control at the level of complex IV, relative to complexes I and II. Here, we investigate mitochondrial function at the level of metabolites. We compare six different species of bivalves with a maximum longevity varying from 4 to over 500 years to assess whether differences in flux control between species relate to metabolites concentrations, and whether these could explain the lower ROS production and the adjustments in signaling functions of mitochondrial metabolites in long-lived species.

A13.42 CHARACTERIZING MICROPLASTIC INGESTION, TRANSFORMATION, AND EXCRETION IN INSECTS USING FLUORESCENT PLASTICS

Wednesday 5 July 2023 POSTER SESSION

Marshall W Ritchie (Carleton University, Canada), Alexandra Cheslock (Carleton University, Canada), Madelaine P.T Bourdages (Carleton University, Canada), Bonnie M Hamilton (University of Toronto, Canada), Jennifer F Provencher (Environment and Climate Change Canada, Canada), Jane E Allison (Carleton University, Canada), Heath A MacMillan (Carleton University, Canada)

marshallritchie@cmail.carleton.ca

Plastic pollution is a growing threat to our natural environment. Plastic waste/pollution results from high emissions of both macro (> 5 mm) and microplastics (MPs; < 5 mm) as well as environmental fractioning of macroplastics into microplastics. Harmonized methods to accurately measure and count MPs from animal samples are limited, but what methods exist are not ideal for a controlled laboratory environment where plastic ingestion, transformation, and elimination can be quantified and related to molecular, physiological, and organismal traits. Here we provide a complete workflow that allows for highly repeatable characterization and quantification of microplastics from animal samples. This approach uses free software and common equipment found in a laboratory setting, where this method is most applicable and most needed at present. As a proof of concept, we quantified microplastics in cricket frass collected throughout development while they were fed a diet containing microplastics. It was demonstrated that this method can be modified to be used on insects' digestive tracts and could effectively capture the MPs within gut samples while preserving the tissue for other approaches (e.g. histology or biochemistry). We also validated our automated approach by comparing it to independent manual counts from researchers. Our method saves time and removes errors associated with manual counting, increasing repeatability.

A13.43 HIAT1, A NOVEL AMMONIA TRANSPORTER

Wednesday 5 July 2023 POSTER SESSION

Dirk Weihrauch (University of Manitoba, Canada), Sandra Fehsenfeld (Université du Quebec à Rimouski, Canada), Haonan Zhouyao (Baylor College of Medicine, United States), Andrew Donini (York University, Canada), Andrea Durant (University of Miami, United States), Alex R. QuijadaRodriguez (University of Manitoba, Canada)

Dirk.weihrauch@umanitoba.ca

Over the last 2 decades, our knowledge of transepithelial ammonia transport mechanisms and ammonia transporters has increased substantially, mostly due to the finding that Rh-like glycoproteins mediate the transport of ammonia and can usually be found highly expressed in excretory tissues of animals. Besides being excreted as nitrogenous waste from the body fluids in the kidneys and gills, each singular cell of any given organism produces ammonia. Excretion pathways of this toxic molecule from the cytoplasm into circulation, however, still need to be explored.

Most recently, our group discovered that a so far not characterized membrane protein, HIAT1 (Hippocampus Abundant Transcript 1 protein), cloned from crustaceans, chelicerates, and fish, acts as a novel ammonia transporter when functionally expressed in frog oocytes.

This transporter is highly conserved in the animal kingdom, sharing e.g. 72% amino acid similarities betweenTrichoplax and mammals. Interestingly, expression of HIAT1 is not restricted to excretory tissues but can be found in all tissues so far investigated at rather similar expression levels, in crustaceans e.g. in ganglia, heart muscle, hypodermis antennal glands, and gills.

Experiments suggest that HIAT1 mediates the transport of ionic ammonia, NH4 + , and functions in a Na+ - dependent manner, promoting ammonia secretion out of the cytoplasm.

Expression of HIAT 1 in very early larval stages in fish and in the amphibian oocyte, suggests crucial importance in cellular ammonia and pH regulation.

We here present a summary of our most current findings on HIAT 1 in invertebrates and fish.

A13.4 EFFECTS OF TURBIDITY ON THE STRESS RESPONSE OF PACIFIC WHITE SHRIMP LITOPENAEUS VANNAMEI

Wednesday 5 July 2023

POSTER SESSION

Cian M Greene (University of the West of Scotland, United Kingdom), Lukas Neumann (Skretting ARC, Norway), Charles McGurk (Skretting ARC, Norway), Mhairi E Alexander (University of the West of Scotland, United Kingdom), Phillip Cowie (University of the West of Scotland, United Kingdom), Katherine A Sloman (University of the West of Scotland, United Kingdom)

Cian.Greene@uws.ac.uk

The commercial production of Pacific white shrimp (Litopenaeus vannamei) is a fast growing and highly profitable industry that is susceptible to large losses in profit as a result of disease outbreaks caused by stress. Water quality parameters such as turbidity can be a major cause of stress in commercial shrimp production, and while

the effects of turbidity on productivity of penaeid shrimp have been investigated, little is known about how turbidity can affect shrimp responses to routine husbandry stressors such as handling. Here we examined the physiological response of shrimp to handling using known physiological indicators of stress (haemolymph osmoregulatory capacity, glucose, total protein concentration) that could potentially be measured under commercial settings. Additionally, the influence of turbidity on the stress response exhibited by the shrimp to handling was measured to determine if the same physiological changes occurred under differing turbidities. It was found that turbidity significantly influenced the physiological response to handling stress, and warrants exploration in future studies to further understand the effects of turbidity on L. vannamei.

A13.45 FRECOVERY OF REEF SHARK POPULATIONS INVOKES ANTI-THREAT BEHAVIOURS IN MESOPREDATORY REEF FISHES ON A CORAL REEF

Wednesday 5 July 2023 POSTER SESSION

Zoe Storm (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom), Mark G Meekan (Australian Institute of Marine Science (AIMS), Australia), Conrad W Speed (Australian Institute of Marine Science (AIMS), Australia), Shaun S Killen (University of Glasgow School of Biodiversity One Health and Veterinary Medicine, United Kingdom), Emily K Lester (Australian Institute of Marine Science (AIMS), Australia)

zoectstorm@gmail.com

There is considerable controversy around the potential for reef sharks to structure fish communities in coral reefs via consumptive and nonconsumptive predator effects, including changes in prey behaviour. Ashmore Reef, off the coast of Western Australia, is an excellent study system to shed light on reef sharks’ roles in structuring fish communities since effective management of a no-take marine reserve allowed reef shark populations to recover from low abundances (due to overfishing) in 2004 to high numbers in 2016. Following the recovery of shark populations, a decline in the abundance of small mesopredatory reef fishes, and an increase in medium and large ones, was recorded via Baited Remote Underwater Video Systems (BRUVS). However, any non-consumptive effects remain unknown. We explored whether the recovery of shark populations was also accompanied by changes in the risk-taking behaviour of these size classes of mesopredatory fishes. We found support for both short-term (within year: prior to and after shark arrival in the video) and long-term (between years: prior to and after the recovery of shark populations) effects of reef sharks on behaviours of small and some medium-sized mesopredatory fishes. Our study suggests that the decline of small mesopredatory fishes following reef shark recovery could be due to both the consumptive and non-consumptive impacts of sharks as predators in this system while an increase in large mesopredators may largely be linked to consumptive predator effects. Our study shows the importance of combining behavioural and demographic studies when studying the determinants of fish community structure.

A13.46 THYROID HORMONES INFLUENCE DEVELOPMENT OF SKELETAL MUSCLE MITOCHONDRIA PHENOTYPE AND THERMOREGULATION IN NESTLING REDWINGED BLACKBIRDS.

Wednesday 5 July 2023 POSTER SESSION

Edward M Dzialowski (University of North Texas, United States), Sarah Sirsat (SUNY Potsdam, United States), Edwin R. Price (University of North Texas, United States), Megan Pineda (FUJIFILM Diosynth Biotechnologies, United States), Janna Crossley (UT Southwestern, United States), Tushar S. Sirsat (Clarkson University, United States)

ed.dzialowski@unt.edu

Thyroid hormones are key regulators of mitochondria function and whole animal metabolism in vertebrates. Plasma 3,3’, 5-triiodoL-thyronine (T3 ) levels in altricial red-winged blackbird nestlings increase during the first 5 days post-hatching (dph). These nestlings begin to develop endothermic metabolic responses by 7 dph and fledge within 10 days of hatching. To better understand the role thyroid hormones play in mitochondria and endothermic metabolic development in an altricial bird, we treated nestling red-winged blackbirds on 2, 3, and 5 dph with either methimazole (MMI) to induce hypothyroidism or supplemental T3 to induce hyperthyroidism. We measured mitochondrial function in permeabilized breast and thigh skeletal muscle fibers at 5, 7 and 9 dph. Hypothyroid conditions prior to day 5 post-hatching induced lower oxygen flux during oxidative phosphorylation through complexes I and II than controls in both breast and thigh skeletal muscles of 7 and 9 dph nestlings. Elevating thyroid hormones during the first 5 dph resulted in greater leak respiration but no change in oxidative phosphorylation respiration later in the nestling period. During the nestling period, breast muscle mitochondria function was a better predictor of resting metabolism and endothermic capacity than thigh muscle mitochondrial function. These data suggest that thyroid hormone levels play a role in development of skeletal muscle mitochondrial function and may represent a foundational mechanism by which endothermic capacity is achieved by neonate altricial birds.

A13.47 ASSOCIATING CHRONIC STRESS, QUANTIFIED BY SCALE CORTISOL, WITH GROWTH REDUCTION AND HEART REMODELING OF ATLANTIC SALMON (SALMO SALAR)

Wednesday 5 July 2023

POSTER SESSION

April Grace R Opinion (University of Antwerp Department of Biology ECOSPHERE, Belgium), Marine Vanhomwegen (Ghent University Department of Biology Stress Physiology Research Group (StressChron), Belgium), Gudrun De Boeck (University of Antwerp Department of Biology ECOSPHERE, Belgium), Johan Aerts (Ghent University Department of Biology Stress Physiology Research Group (StressChron), Belgium)

aprilgrace.opinion@uantwerpen.be

Stress and elevated glucocorticoids, particularly cortisol in teleost fish, have been linked with pathological remodeling of the heart, and

deterioration of fish fitness and welfare. However, these associations were based on biomarkers that fail to provide a retrospective view of stress. This study is the first to unravel the association of cortisol in scales, as chronic stress biomarker, with cardiac morphology and whole-animal performance of Atlantic salmon (Salmo salar). Growth, heart morphology, plasma and ontogenetic scale cortisol levels, and expression of genes involved in cortisol regulation of the hypothalamic-pituitary-interrenal (HPI) axis of undisturbed fish (CONTROL) were compared to fish exposed daily to random stressors (STRESS) for 8 weeks. Though scale cortisol levels showed a timedependent accumulation in both treatments, the cortisol levels of STRESS fish in plasma and scales were 29.1% and 25.0% lower than CONTROL, respectively. These results can be attributed to the significant upregulation of both glucocorticoid and mineralocorticoid genes (gr and mr) involved in the negative feedback in STRESS treatment, coupled with the lack of strong indication for excess de-novocortisol synthesis manifested by the stable crh, pomcs , and star gene expression. The cortisol levels are, however, counterintuitive to the growth performance as STRESS fish grew 33.7% slower than CONTROL. Moreover, STRESS fish had 8.4% relative ventricle mass (RVM), a maladaptive response documented in cortisol-exposed fish. Nevertheless, heart histology showed comparable compact/spongy myocardium proportion and extra-bundular sinus area between the treatments, which suggests heart growth as an adaptive response to enable fish to survive (chronic) stressful conditions.

A13.49 EFFECTS OF WARMING, HYPOXIA AND HYPERCAPNIA ON BRANCHIAL CELL HOMEOSTASIS OF KING SCALLOPS (PECTEN MAXIMUS)

Wednesday 5 July 2023 POSTER SESSION

Sandra Götze (Alfred-Wegener Institute, Germany), Charlotte Eymann (Alfred-Wegener Institute, Germany), Gisela Lannig-Bock (Alfred-Wegener Institute, Germany), Christian Bock (Alfred-Wegener Institute, Germany), HansOtto Pörtner (Alfred-Wegener Institute, Germany)

sandra.goetze@awi.de

A13.48

EXPORING THE ROLE OF MICROBIOME IN REPRODUCTIVE FUNCTIONS OF DROSOPHILA MELANOGASTER MALES.

Wednesday 5 July 2023

POSTER SESSION

Komal Maggu (Department of Evolutionary biology and Environmental StudiesUniversity of Zurich, Switzerland)

komal.maggu@uzh.ch

Research in past two decades has revealed that physiological functions of organisms depend not only upon the underlying genes and the environment but also on the microbes living in and on them (i.e., microbiota). Especially the gut microbiota has emerged as an influential contributor to many aspects of its host’s life. Surprisingly little is known, however, about the influence of commensal (harmless) microbes on their host’s reproductive health, even less so for males than for females.Changes in the reproductive performance mediated by altering microbial compositions could be particularly consequential for males in species where females mate multiply and thus causing sperm from different males to compete for fertilization. However, the links between the microbiome and competitive fertilization success of males remain unexplored. Therefore, through this study we investigated these unexplored links between microbiota and malereproductive investment. Using Drosophila melanogaster as a study system, we manipulated the microbial composition in flies to study its effects on fertilization success of males. We found that both the level of microbiome complexity and the identity of bacterial species affected the competitive fertilization success in males. Higher microbiome diversity and the presence of Acetobacter species (compared to Lactobacillus) improved fertilisation success of males. To our knowledge, this is the 1st evidence depicting the role of microbiome in shaping competitive fertilization success of D. melanogaster males. These findings could provide new insights for development of microbiome-based strategies for pest control in other species to address agricultural losses.

Unfavorable environmental conditions, beyond the species thermal optimum, challenge and ultimately impair cellular homeostasis. We assessed how the branchial homeostasis of King scallops (Pecten maximus) was affected by acute warming (W), warming plus hypercapnia (WHc; >90 % PO2, 1800 µatm CO2), warming plus hypoxia (WHo; 55-60 % PO2, ~550 µatm CO2), and the combination of all three ocean climatic drivers (Deadly trio, DT, 55-60 % PO2, and 1800 µatm CO2). Starting at 14 °C, temperature was increased stepwise (2 °C/48 h) until the lethal temperature was reached (close to 28 °C). Gills samples were taken at 14, 18, 22 and 26 °C. We assessed various indicators of intracellular stress (lipid peroxidation, protein damage and degradation, rate of apoptosis) and defense (heat shock response, antioxidative capacity). In W, WHo, and WHc a heat-shock response occurred at 26 °C while levels of ubiquitin-conjugates (protein damage) and branched chain amino acids (protein degradation) remained low. In DT-exposed scallops HSP70 levels remained low throughout although ubiquitin-conjugates accumulated at 18 °C and 22 °C followed by elevated levels of branched-chained amino acids at 26 °C indicating enhanced protein degradation. Gill structure was visibly disrupted at 26°C, however, the rate of apoptosis was not elevated. In conclusion, gills are resilient against short-term acute exposure to W, WHo, and WHc even close to the lethal temperature, but exposure to all three drivers (DT) induced protein damage and protein catabolism.

A13.50 METABOLIC DISTURBANCE AND RECOVERY IN DWARF CICHLIDS AFTER CATCH-AND-RELEASE PROCEDURES IN THE ORNAMENTAL FISHERY

Wednesday 5 July 2023 POSTER SESSION

Shaun S Killen (University of Glasgow, United Kingdom), Oluwaseun Ojelade (Federal University of Agriculture, Nigeria), Zoe Storm (University of Glasgow, United Kingdom), Cheng Fu (University of Glasgow, United Kingdom), Daphne Cortese (University of Glasgow, United Kingdom), Sarah Boulamail (University of Glasgow, United Kingdom), Mar Pineda (University of Glasgow, United Kingdom), Dainai Kochhann (Universidade do Vale do Acaraú, Brazil)

shaun.killen@glasgow.ac.uk

Fishing can have direct effects on wild populations via the removal of harvested individuals, and indirect effects due to physiological disturbance in fish released after capture. While catch-and-release has been well-studied in the commercial and recreational fisheries, this issue has been overlooked for fisheries in the ornamental fish trade,

where it is common to release non-target species. We examined the metabolic response to capture-and-release procedures in the dwarf cichlid species Apistogramma trifasciata, a popular aquarium species that is nonetheless often discarded in favour of more marketable dwarf cichlid species. Forty individuals were tagged and exposed to one of four treatments: 1) a non-handling control; 2) a netting treatment; 3) netting + 30 seconds of air exposure; and 4) netting + 60 seconds of air exposure. After each treatment, metabolic rates were then estimated using intermittent flow respirometry. All fish were also independently measured for maximum metabolic rate after manual chasing. In general, increasing amounts of handling caused and increased metabolic disturbance and decrease in available aerobic scope, although there was a large degree of variation among individuals. Furthermore, many individuals showed recovery within a 12-hour measurement period. Interestingly, for many individuals, the maximum metabolic rate estimated following handling stress exceeded that estimated during the chase protocol. Overall, the results here suggest that in the hours following capture and release, individual dwarf cichlids may experience increased energy expenditure and a reduced aerobic capacity for processes involved in feeding or locomotion.

A13.51 TURNING DOWN THE HEAT: ROLE OF SECRETED

BATOKINES IN EVOVLED VARIATION OF BROWN ADIPOSE TISSUE MATURATION

Wednesday 5 July 2023 POSTER SESSION

Cayleih E. Robertson (Stockholm University, Sweden), Fiona Weaver (McMaster University, Canada), Susanne Keipert (Stockholm University, Sweden), Martin Jastroch (Stockholm University, Sweden), Colin Nurse (McMaster University, Canada)

cayleih@gmail.com

Activation of brown adipose tissue (BAT) thermogenesis impacts energy balance and must be tightly regulated. In altricial mammals, BAT matures during the first weeks after birth. In wild rodents the timing of the maturation of BAT can be altered by rearing temperature or ancestry. For example, BAT matures slower in deer mice (Peromyscus maniculatus) native to high elevations. Several neurotrophic factors, secreted by BAT, have been implicated in establishing the sympathetic neural network to enhance thermogenesis during development (e.g., NRG4 and S100b). We used two lab reared populations of deer mice native to high (HA) and low altitude (LA), to determine if evolved differences in BAT maturation are driven by differential regulation of sympathetic innervation. We compared the relative roles of NRG4 and S100b in establishing BAT innervation during postnatal development. We found that BAT of HA pups had a less complex sympathetic neuronal network. However, there was no difference in gene expression, endogenous protein stores or secretion of either factor between populations. In fact, conditioned media (CM) from cultured BAT slices of HA pups maximally stimulated neurite outgrowth from sympathetic neurons in vitro, suggesting that HA pups secrete large quantities of neurotrophic factors. Instead, the S100b receptor (RAGE) was downregulated in HA sympathetic neurons. RAGE, which may block adrenergic stimulation of BAT was also highly expressed in brown adipocytes of highland pups. Our data suggest that secreted ‘batokines’ likely have autocrine and paracrine effects during development. Understanding BAT’s secretory role, is critical to understanding mammalian energy homeostasis

A13.52 CALIBRATION FOR QUANTIFYING THE STRONTIUM-TOCALCIUM RATIOS OF ARAGONITIC SHELLS USING EPMA WITH WDS

Wednesday 5 July 2023

POSTER SESSION

Takahiro Irie (The University of Tokyo, Japan), Iki Murase (The University of the Ryukyus, Japan)

irie@aori.u-tokyo.ac.jp

The ratio of strontium to calcium (Sr/Ca) in aragonitic hard parts has been of interest for the purpose of sclerochronologically estimating the temperature experienced by marine organisms. The elemental composition of carbonate structures has been increasingly quantified by LA-ICP-MS, but EPMA with WDS (wavelength dispersive X-ray spectrometer) also retains its significance. One of the reasons is that some elements cannot be accurately quantified by ICP-MS due to the spectral interference. Another reason is that the surface analysis in EPMA is less destructive than laser ablation. Furthermore, WDS and ICPMS are based on different physical principles, which means that pattens obtained independently from the same sample can be cross-validated. However, in order to accurately estimate the Sr/Ca of a new sample from the X-ray intensity output of EPMA, a functional relationship between the two quantities must be established in advance.. In the present study, we aimed to establish the calibration line by rearing an intertidal gastropod (Monetaria annulus) at 6 different levels of constant temperature and then analysing the same set of shell specimens using both ICP-MS and EPMA (n = 227). The calibration line we obtained can be applied to fish otoliths, molluscan statoliths, and coral skeletons as well as aragonitic shells of other molluscan species to quantify their Sr/Ca values using EPMA.

A13.53 TEMPERATURE PREFERENCE AND ACCLIMATION CAPACITY OF TADPOLES LIVING IN CONTAINER HABITATS

Wednesday 5 July 2023

POSTER SESSION

Chi-Shiun Wu (Chinese Culture University, Taiwan),

Yi Ming Wu (Chinese Culture University, Taiwan),

Fan Cyuan Kong (Chinese Culture University, Taiwan),

Yi Ru Lee (Chinese Culture University, Taiwan),

Yi Cyun Jheng (Chinese Culture University, Taiwan)

buergeria@gmail.com

Studies on thermal physiology is necessary if we want to predict the potential effects of global warming on ectotherms. The behavioral thermoregulation is one of important strategies to cope with environmental temperature fluctuations in tadpoles. By selecting preferred temperatures, tadpoles can maximize growth and development. In theroy, acclimation to different temperatures can alter thermal preference of tadpoles. However, few studies have addressed if the acclimation effects on temperature preference of tadpoles are universal, especially the degree to which tadpoles are able to adjust their thermal sensitivity (acclimation capacity). In this study , tadpoles of Babina adenopleura, Polypedates braueri, Polypedates megacephalus, Rhacophorus prasinatus, and Microhyla fissipes collected from container habitats were reared in high or low water temperature, to test if thermal acclimation capacity of

temperature preference is universal among tadpole species. Results showed that preferred temperature of the five tadpole species does not increase with increasing acclimation temperature, ssuggesting that these tadpole species lack acclimation capacity in temperature preference. Therefore, we predict that these tadpoles living in container habitats will be vulnerable to climate warming because they may not adjust preferred temperature in response to increasing temperature of microhabitats for adaptation to a new thermal environment.

A13.54 TESTING THE THRIFTY AND SPENDTHRIFT GENOTYPE HYPOTHESES: THE EXPERIMENTAL EVOLUTION AND THE “NATURE-NURTURE” EXPERIMENT ON BANK VOLES

Wednesday 5 July 2023

POSTER SESSION

Alaa Hseiky (Doctoral School of Natural and Exact Sciences

Jagiellonian University in Krakow, Poland), Natalia Strzelczyk (Institute of Environmental Sciences Faculty of Biology

Jagiellonian University in Krakow, Poland), Katarzyna

Baliga-Klimczyk (Institute of Environmental Sciences Faculty of Biology Jagiellonian University in Krakow, Poland), Małgorzata M. Lipowska (Institute of Environmental Sciences

Faculty of Biology Jagiellonian University in Krakow, Poland), Edyta T. Sadowska (Institute of Environmental Sciences

Faculty of Biology Jagiellonian University in Krakow, Poland), Paweł Koteja (Institute of Environmental Sciences Faculty of Biology Jagiellonian University in Krakow, Poland)

alaa.hseiky@doctoral.uj.edu.pl

Obesity and co-occurring disorders have become a common problem in humans. The immediate causes are the “Western Diet” (WD), rich in fats and simple sugars, along with reduced physical activity. Many hypotheses tried to explain why we are vulnerable to such conditions. The “thrifty-genotype” hypothesis assumes that natural selection promoted efficient storage of fat reserves to endure starvation. Nowadays, however, with easy access to food, fat is continuously stored leading to various disorders. Its logical counterpart, the “spendthriftgenotype” hypothesis states that animals with evolved high metabolic capacity under unrestricted food access should be less vulnerable to the adverse effects of such an excess. Both hypotheses were simultaneously tested using lines of bank voles (Myodes glareolus) artificially selected in three directions: “Herbivorous” with the ability to grow on low-quality diet, “Aerobic” with high swim-induced aerobic metabolism, and “Predatory” with a propensity to hunt crickets; and unselected Control lines. The Aerobic and the Predatory lines represent the spendthriftgenotype, while the Herbivorous the thrifty-genotype. The voles were assigned to WD or standard diet groups shortly after weaning, and three months later several traits were analyzed. Surprisingly, body mass, fat content, blood glucose, and locomotor performance traits were not affected by WD. In the WD group, liver and spleen were enlarged and plasma biochemical markers indicated a compromised liver function, but most of the effects were similar in all the selection lines. These results show that the voles are highly resistant to the WD, and provided no support for either of the hypotheses.

A13.55 UNUSUAL SEX DETERMINATION IN THE LYCORIELLA INGENUA FUNGUS GNAT FLY

Wednesday 5 July 2023 POSTER SESSION

Maria A Shlyakonova (University of Glasgow and University of Edinburgh, United Kingdom), Robert B. Baird (University of Edinburgh, United Kingdom), Laura Ross (University of Edinburgh, United Kingdom)

maria.shlyak@gmail.com

Sex is an ancient feature among animals, but sex-determination mechanisms are diverse. Most species have regular zygotic sex determination systems, like the XY system in humans. However, in some cases, sex determination can be influenced by the environment or even the mother. Dark-winged fungus gnats (Diptera: Sciaridae) exhibit unusual reproductive strategies where some species produce mixed-sex (digenic) broods and other species produce single-sex (monogenic) broods, and the sex ratio has both environmental and maternal components. Sex is determined by the maternally-controlled elimination of paternal chromosomes in the developing zygotes. Previous studies showed that Bradysia ocellaris (digenic) has sex ratios that are heritable and are affected by temperature. Here we investigated the heritability and temperature effects on sex ratios in another species of Sciaridae, Lycoriella ingenua, a common pest of mushroom farms. We hope our findings will improve our understanding of unusual sex determination systems.

A13.56 OPPOSING EFFECTS OF SEASONAL AND RAPID COLOUR VARIATION IN A CORDYLID LIZARD: IMPLICATIONS FOR THERMOREGULATION

Wednesday 5 July 2023

POSTER SESSION

Susana Clusella-Trullas (Stellenbosch University, South Africa), Federico Massetti (Stellenbosch University, South Africa), Liliana D'Alba (Ghent University, Belgium), Matthew D. Shawkey (Ghent University, Belgium)

sct333@sun.ac.za

Temperature is often proposed as a driver of melanisation in ectotherms, conferring thermal benefits to darker phenotypes in cold conditions. However, the association between skin reflectance and temperature is often tenuous, varying among studies and species. This inconsistency may be due to multiple mechanisms (e.g., cryptic colouration, pathogen resistance) playing a role on colour variation. In addition, the thermal benefit of skin colour may only be apparent at specific temporal scales and/or body regions. Here, we assess the magnitude of skin reflectance change of a cordylid lizard from South Africa (Cordyluscordylus) at both short

A13.57 STATISTICAL PROPERTIES OF X-RAY INTENSITY OUTPUT FROM EPMA

WITH WDS FOR QUANTIFYING THE STRONTIUM CONCENTRATION IN ARAGONITIC SHELLS

Wednesday 5 July 2023 POSTER SESSION

Iki Murase (University of the Ryukyus, Japan), Takahiro Irie (The University of Tokyo, Japan)

iki.murase@gmail.com

Biogenic calcium carbonate structures such as molluscan shells and fish otoliths contain >30 of minor and trace elements. The elemental composition is often quantified by using Electron Probe Micro Analyzer (EPMA) with the wavelength dispersive X-ray spectrometer (WDS), Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LAICP-MS), and/or Secondary Ion Mass Spectroscopy (SIMS). EPMA provides reliable data even by emitting the electron beam with a diameter of 1 μm, and may be superior to LA-ICP-MS in terms of spatial resolution. However, X-ray intensity output from EPMA is quite dispersive, which means that one has to average out the measurement error by repeatedly observing the same position of a sample surface to improve the precision. Here, we investigated the statistical properties of the output from EPMA with WDS, by analysing Monetaria annulus shells prepared by rearing wild-collected individuals at constant temperatures. We investigated 1) the effect of probe current, beam diameter and/or beam exposure time on measurement precision and 2) the effect of repeatedly focusing the electron beam on the same spot of a sample surface on X-ray intensity.

A13.58 SEXUAL DIFFERENTIATION IN ANNUAL METABOLITES ADJUSTMENTS OF TROPICAL FISH: INSIGHTS FROM A MACHINE LEARNING

Wednesday 5 July 2023

POSTER SESSION

Min-Chen Wang (Academia Sinica, Taiwan), Ching-Wei Wang (Academia Sinica, Taiwan), Tzu-Hao Lin (Academia Sinica, Taiwan), Yung-Che Tseng (Academia Sinica, Taiwan)

mcwinlab@gmail.com

As the physiological processes are energy-limited, organisms keep adjust their energy allocation to meet with the continuous physiological regulation in the annual cycle. Anisogamous species usually exhibit a pattern those females usually provide a larger energy investment in the form of yolk during gamete production. In contrast, males tend to invest less in the gamete production compared to females. The inherent difference of male and female results in the difference of energy allocation strategies between the sexes. This study collected the serum of tropical tilapia (Oreochromis mossambicus) and performed the metabolomics to investigate the sexual annual variations difference of fish. In the study, the annual metabolites variation and the importance of each metabolite in the certain month are identified by the machine-learning algorithms. The result exhibits the sexual difference of amino acids variations in tilapia before the reproduction season. This study is expected to fill the gap in our understanding of how different sex of tilapias adjust the energy budget for homeostasis in a seasonal cycle and provide a piece of feasible nutrient supply information that benefits to aquaculture improvement in the tropical/subtropical area.

A13.59 BEHAVIOURAL RESPONSE TO HYPOXIA IN TRINIDADIAN GUPPY (POECILIA RETICULATA)

Wednesday 5 July 2023 POSTER SESSION

Elise Doddema (University of Bergen, Norway), Malin Fløysand (University of Bergen, Norway), Andrea ComposCandela (University of Bergen, Norway), Rachael Morgan (University of Bergen, Norway)

ldo006@uib.no

It is postulated that in densely vegetated aquatic environments, oxygen levels may fluctuate on a daily basis, resulting in low levels of oxygen towards dawn. This creates a crucial ecological trade-off for the inhabitants of such habitats, which serve as both shelter and nursery grounds. Hypoxia, or low oxygen levels, can affect the behaviour of fish due to neurological and physiological disruptions. In this study, we investigated the potential impairment of fish senses and energetically expensive processes such as activity under hypoxic conditions. The Trinidadian guppy (Poecilia reticulata) was used as the model organism, with 96 individuals being distributed among 12 tanks. Half of the tanks experienced daily hypoxic fluctuations, while the remaining six were kept under normoxic conditions. After two weeks of acclimation, activity levels and startle response were measured under normoxia, acute hypoxia, and during recovery from hypoxia. It was predicted that reduced energy availability and impaired senses would result in decreased activity and longer response times. Additionally, previous acclimation to hypoxia may lead to physiological adjustments resulting in improved performance, such as higher activity and shorter response times.

A13.60 INSECT COUNTER-ADAPTATION TO PLANT PHYSICAL DEFENCES: HOW DO SPECIALISED HELICONIINI CATERPILLARS COPE WITH SHARP PASSIFLORA TRICHOMES?

Wednesday 5 July 2023

POSTER SESSION

Ritabrata Chowdhury (University of Cambridge, United Kingdom), Erika De Castro (University of Cambridge, United Kingdom), Walter Federle (University of Cambridge, United Kingdom)

rc855@cam.ac.uk

Plants protect themselves against insect herbivory by chemical and physical defences, but some insects have evolved counter-adaptations to feed on these plants. So far, physical plant defences are less well understood than chemical defences, and it is unclear if insects can also develop counter-adaptations against them. In this study, we investigated how hooked trichomes in Passiflora adenopoda act as a physical defence against Heliconiini caterpillars, and how some caterpillar species can cope with these trichomes. Behavioural observations and video recordings showed that the hooked trichomes arrest Heliconius melpomene and Heliconius erato caterpillars on the leaves by piercing their soft cuticle and causing wounds near the prolegs in large caterpillars and on the main body in small caterpillars. In contrast,Heliconius charithonia and Dryas iulia caterpillars could easily walk on the leaves with hooked trichomes due to their thicker

and more robust cuticle. Penetrometry measurements and histology confirmed that the cuticle of H. charithonia and D. iulia caterpillars is more puncture-resistant. Our findings provide a clear-cut case that herbivorous insects can evolve counter-adaptations to physical plant defences, and add an important but as yet little-explored aspect to our understanding of the evolutionary arms-race between Passiflora and Heliconius.

A13.61 EXCRETION OF SEX PHEROMONE BY GLANDS IN MOTHS

Wednesday 5 July 2023 POSTER SESSION

Mourad Jaffar-Bandjee (Max Planck Institute of Colloids and Interfaces, Germany), Richard Weinkamer (Max Planck Institute of Colloids and Interfaces, Germany), Jérôme Casas (Insect Biology Research Institute, France), Peter Fratzl (Max Planck Institute of Colloids and Interfaces, Germany)

mourad.jaffar-bandjee@mpikg.mpg.de

Many species of moths rely on sex pheromone to attract conspecific mates. In most cases, females release very limited amount of these chemicals through dedicated organs, the pheromones glands. In the silkworm, Bombyx mori, these glands are composed of two inflated sacs with one layer of secreting cells at their surface, covered by a layer of cuticle. The cuticle is a physical barrier, which protects the inner organs of the insects and prevent water losses. However, it is also impermeable to pheromone. Glands developed a network of channels to carry the pheromone through the cuticle, from the secreting cells to the surrounding air. This channel network ends in some hair-like cuticular structures, raising the question of the existence of such structures. Additionally, it was observed with bare eyes that, in a single species of moths, sex pheromone is excreted in the form of aerosols. In this work, we want to characterize the physical conditions that allow the excretion of the sex pheromone.

We first map this network of channels using Scanning and Transmission Electron Microscopy. Second, we measure the pheromone viscosity to understand how it flows in the channel network. Third, we determine how the pheromone is excreted, as a film covering the surface or as aerosols. Our approach combines experimental observations and computer simulations.

We hope this research will contribute to better understand chemical communication among insects and introduce new solutions for generating monodispersed aerosols

A13.62 PATTERNS OF FATTY ACID UPTAKE AND OXIDATION IN A REPTILE AND A SMALL MAMMAL

Wednesday 5 July 2023 POSTER SESSION

Shahar Dubiner (Tel Aviv University, Israel), Ariel Drabkin (Tel Aviv University, Israel), Amit Kashi (Tel Aviv University, Israel), Pablo Blinder (Tel Aviv University, Israel), Eran Levin (Tel Aviv University, Israel)

dubiner@mail.tau.ac.il

Fatty acid (FA) saturation levels in the diet have been demonstrated to be allocated and utilized differently by the body in various species, affecting physiology, behaviour, and health. Studies indicate differences in their usage as metabolic fuel compared with allocation in tissues. However, different rates of intestinal absorption exist between these fatty acids, potentially biasing conclusions of functional differences and their subsequent implications. In our study we tested fatty acid usage by a nocturnal, insectivorous gecko Hemidactylus turcicus and a nocturnal, insectivorous shrew of similar body mass Suncus etruscus. We compared the relative presence of heavy isotopes (δ13 C) in the breath and faeces, following three different feeding treatments of 13 C1 isotopically enriched fatty acids. The treatments were linoleic acid (LA; a polyunsaturated FA), oleic acid (OA; monounsaturated), and palmitic acid (PA; saturated), given with a cricket. PA oxidation was much lower than that of OA and LA. PA egestion was much higher than that of LA and OA, although they too were higher than the control. The major difference between the two species was in the time it takes them to use the FAs, regarding both the time until peak δ13 C values and its duration. Both were longer in geckos, but metabolic rate alone, independent of species, was the best predictor of differences in peak duration. Circadian rhythms were evident for metabolic rates (geckos) and FA oxidation (both species). This study provides insights into the oxidation and absorption patterns of different FAs, and their relationship with metabolic rates in vertebrates.

A13.63 ESTABLISHING THE PHYSIOLOGICAL VALUES OF NONINVASIVE BIOMARKERS IN TELEOSTS

Wednesday 5 July 2023

POSTER SESSION

KATERINA A. MOUTOU (UNIVERSITY OF THESSALY, Greece), Rafael Angelakopoulos (University of Thessaly, Greece), Alexia Fytsili (University of Thessaly, Greece), Andreas Tsipourlianos (University of Thessaly, Greece), Themistoklis

Giannoulis (University of Thessaly, Greece)

kmoutou@uth.gr

Peripheral blood has been always used as the mirror of the physiological status in a non-invasive manner. In homeothermic vertebrates, different blood parameters have been correlated to a variety of biochemical and physiological processes and the establishment of physiological values have rendered them valuable indicators for research, diagnosis and welfare status. Teleosts form the most numerous vertebrate groups, with an incredible capacity for ecological adaptation and high significance for food security. Despite the volume of research in fish physiology, information about physiological values of non-invasive biomarkers is still fragmented while there is a great need for such biomarkers for monitoring fish health, welfare and factors that can impact their homeostasis. For the first time, we have focused on determining the physiological ranges of cholesterol, triglycerides, and total proteins in the plasma of gilthead sea bream (Sparus aurata) and detecting how age/size, feed and genetic background may influence these levels. A large heterogeneous dataset of 5271 healthy individuals of two different size classes (0-100g; 101-200g), different genetic background (127 families) and dietary status (10 feeds and feeding schemes) was created in three years and analysed to ensure a comprehensive representation in establishing the physiological range for these biomarkers. Dietary status and genetic background introduced significant variation in the range of the physiological values of all biomarkers in both age/size classes. Unlike triglycerides and total protein, cholesterol values did not differentiate with age/size. Interestingly, all parameters responded to diet in an sizespecific way revealing their potential as biomarkers of dietary status.

A13.64 FPERI-METAMORPHIC TIGHT JUNCTION-ASSOCIATED GENE EXPRESSION PATTERNS IN THE SEA LAMPREY (PETROMYZON MARINUS) GILL

Wednesday 5 July 2023

POSTER SESSION

Scott P Kelly (York University, Canada), Chun C Chen (York University, Canada), Julia Sunga (Wilfrid Laurier University, Canada), Michael Wilkie (Wilfrid Laurier University, Canada)

spk@yorku.ca

Anadromous sea lamprey (Petromyzon marinus) are jawless vertebrates that have an indirect development life cycle characterised by three phases; (1) a protracted freshwater (FW) larval period, (2) seven metamorphosing stages (S1 – S7) and (3) a seawater-dwelling adult. During metamorphosis, morphological and physiological alterations prepare the sea lamprey for seawater (SW) residency and life as a parasitic adult. This study examined peri-metamorphic transcript abundance of genes encoding sea lamprey tight junction (TJ) proteins in the gill. Genes encoding TJ proteins occludin (ocln), occludin-a (ocln-a), tricellulin (tric), as well as claudin (cldn)-3b,-10,-14,-18,-19 were examined. Transcript abundance of ocln and ocln-a in the gill did not significantly alter from larval through to metamorphosis stage 7. However, in post-metamorphic young adults residing in FW, gill ocln abundance significantly elevated while ocln-a abundance significantly decreased. No peri-metamorphic alterations in tric mRNA abundance were observed. Transcript encoding Cldn-3b and -19 were also unaltered during metamorphosis. However, at the onset of metamorphosis cldn-18 mRNA abundance increased, peaked at S3 and then significantly reduced in young adults. In contrast, cldn-10 mRNA abundance increased significantly at S6, but was unaltered at any other period. Acclimation of post-metamorphic animals to seawater reduced gill ocln, cldn-3b, cldn-10 and cldn-19 mRNA abundance and increased the abundance of ocln-a and tric mRNA. Data indicate that post-metamorphic SW entry impacts the transcriptional regulation of gill TJ proteins in P. marinus to a greater extent than the ontogenetic transformation that prepares these animals for a parasitic life in SW.

A13.65 EFFECTS OF HYPERGLYCAEMIA ON CARDIAC FUNCTION IN ZEBRAFISH EMBRYOS

Wednesday 5 July 2023

POSTER SESSION

Farah Hussein (University of Manchester, United Kingdom), Sian C J Porter (University of Manchester, United Kingdom), Johanna Smithson (University of Manchester, United Kingdom), Roger G Sturmey (Hull York Medical School, United Kingdom), Holly A Shiels (University of Manchester, United Kingdom), Gina L J Galli (University of Manchester, United Kingdom)

farah.hussein@postgrad.manchester.ac.uk

Gestational diabetes is a pregnancy complication that affects 7-10% of all pregnancies globally and is diagnosed at a glucose level of > 7.8mM. Recent studies have shown offspring from gestational diabetic pregnancies have a higher risk of developing congenital heart diseases, cardiac dysfunction, and hypertension in early childhood. The mechanisms driving cardiac dysfunction in offspring from diabetic

pregnancies are incompletely understood, but may involve metabolic programming during early embryonic development. In this study we hypothesised that early embryonic exposure to glucose can programme cardiac abnormalities, leading to cardiovascular dysfunction in adulthood. We exposed dechorionated zebrafish pigmentation mutant (nacre-/- ) incross embryos to 7.8mM glucose from fertilisation to 5 days post fertilisation (dpf) to mimic gestational diabetes. Firstly, we confirmed that glucose was absorbed by the dechorionated zebrafish embryos by determining extraembryonic glucose with a fluorometric assay. Next, we used an inverted microscope combined with highspeed in vivo imaging to show that hyperglycaemia led to a 9.6% reduction in heart rate, compared to control dechorionated embryos at 2 dpf (p=0.04). These findings suggest that glucose exposure in early embryonic development can alter heart function, potentially leading to cardiovascular programming. Ongoing analysis of cardiac morphology and physiological parameters including cardiac output, ventricular contractility and blood flow rate is being conducted. Future experiments will follow the embryos into adulthood to determine if embryonic hyperglycaemia has long term effects on cardiovascular health and disease susceptibility.

A13.66 INVESTIGATING THE BIOGEOPHYSICAL INTERACTIONS OF HYDROTHERMAL VENTS AND CORAL ECOSYSTEM IN THE NERITIC ZONE

Wednesday 5 July 2023 POSTER SESSION

Ling Chiu (Marine Research Station Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Min-Chen Wang (Marine Research Station Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Yung-Che Tseng (Marine Research Station Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

ken860531@gmail.com

High hydrogen sulphide levels are usually found at hydrothermal vents and are hazardous to the living. The vent crab Xenograpsus testudinatus inhabits a shallow-water hydrothermal vent system located offshore the southeast of Kueishan Island in the northeastern Taiwan. This particular ecosystem has been documented as one of the most acidic and sulphidic marine environments in the world. Strong acid-base regulation, sulphur detoxification ability and the symbiotic sulphideoxidizing bacteria in the gills enable X. testudinatus holobiont to thrive in such extreme conditions. The abiotic-biotic interaction between vent fluids, prokaryotes and eukaryotes manifests hydrothermal activity to establish a specialized biota through inter-kingdom evolution. By contrast, the western tip of Kueishan Island reveals a non-reefal coral ecosystem, exhibiting relatively high biodiversity within 3 km from the venting area. As an epipelagic juncture, climate disturbances, monsoons and the Kuroshio current, apart from the volcanic activity, make Kueishan Island a unique natural laboratory. With spatiotemporal monitoring of soundscape and water quality around the island, we aim to investigate the bio-geophysical interactions between the hydrothermal vent and reef ecosystems, and to delineate the annual dynamics of marine environments subject to a shallow-water hydrothermal vent system

A13.67 EFFECTS OF HYPOXIA AND REOXYGENATION ON MITOCHONDRIAL FUNCTIONS AND TRANSCRIPTIONAL PROFILES OF ISOLATED BRAIN AND MUSCLE PORCINE CELLS

Wednesday 5 July 2023 POSTER SESSION

Linda Adzigbli (Research Institute for Farm Animal Biology (FBN), Germany), Eugene P. Sokolov (Leibniz Institute for Baltic Sea Research Leibniz Science Campus Phosphorus Research Warnemünde, Germany), Klaus Wimmers (Research Institute for Farm Animal Biology (FBN) Institute of Genome Biology Dummerstorf, Germany), Siriluck

Ponsuksili (Research Institute for Farm Animal Biology (FBN) Institute of Genome Biology Dummerstorf, Germany), Inna M. Sokolova (Department of Marine Biology Institute for Biological Sciences University of Rostock Rostock, Germany)

linda.adzigbli@uni-rostock.de

Oxygen fluctuations occur in mammalian tissues under physiological (e.g. high altitudes) or pathological (e.g. ischemia–reperfusion) conditions. Mitochondria are key targets and potential amplifiers of H-R stress. Understanding mitochondrial responses to H-R is important for identifying adaptive mechanisms and potential therapeutic solutions for pathologies associated with oxygen fluctuations. We explored metabolic response to H-R stress in muscle and brain tissues in a domestic pigSus scrofa. Isolated cells from the skeletal muscle (masseter) and brain (thalamus) were exposed to acute short-term (15 min) hypoxia followed by reoxygenation. The mitochondrial functional parameters and transcriptional profiles of hypoxia-responsive mRNA and miRNA were determined. Mitochondria of the porcine brain cells decreased in ATP synthesis capacity whereas that of the muscle cells showed robust respiration and less susceptibility to H-R stress with no influence on ROS production in both cells. Transcriptionally, prolyl hydroxylase domain protein EGLN3 was upregulated during hypoxia and suppressed during with an upregulation of HIF1A transcripts in the muscle cells. However, in the brain cells, HIF1A was suppressed during reoxygenation. Other functionally important transcripts and miRNAs involved in antioxidant response, apoptosis, inflammation, and substrate oxidation were also differentially expressed between the muscle and brain cells. Suppression of miRNA in both brain (~55%) and muscle cells (~25%) signifies transcriptional derepression of the respective mRNA targets. Our study provides insights into the potential molecular and physiological mechanisms contributing to hypoxia sensitivity of the studied tissues and can serve as a foundation to better understand the biological processes associated with H/R and ischemia/reperfusion injury.

EXPLORING THE LINK BETWEEN BEHAVIOURAL PROFILES AND PHYSIOLOGICAL PERFORMANCE IN MIGRATING ATLANTIC SALMON SMOLTS

Wednesday 5 July 2023 POSTER SESSION

Marta Moyano (Norwegian Institute for Water Research, Norway), Silje M. Ulset (University of Agder, Norway), Elise T. Sannes (University of Agder, Norway), Ida B. B. Johansen (Norwegian University of Life Sciences, Norway), Michael Frisk (University of Oslo, Norway), Marco A. Vindas (Norwegian University of Life Sciences, Norway), Erik Höglund (Norwegian Institute for Water Research, Norway)

marta.moyano@niva.no

Atlantic salmon (Salmo salar) is a very important species both culturally and economically worldwide. Wild Atlantic salmon face a number of challenges, such as hydropower plants, which can exert significant selective pressures on vital traits for migrating stages (smolts, prespawners) influencing population diversity. The Nidelva river in southern Norway has been used as a case study where recent research suggested that smolts with higher locomotor activity in response to a novel environment have higher probability of using a fish passage rather than the submerged turbine intake. Given the high mortalities associated with turbine migrantion, this study explored the relationship between locomotor response to a novel environment and physiological traits (swimming performance, heart morphology). Smolts were sorted in two categories, good and bad swimmers, based on time until fatigue in a swimming test: (upper and lower 20%). Good and bad swimmers did not show any differences in body morphometrics (length, weight), nor heart characteristics (morphology, heart rate, relative heart and ventricle mass). Bad swimmers had a higher basal activity at the start of the behavioral test than good swimmers. These results demonstrate a relationship between behavioral profile and swimming performance. However, difference in swimming performance was not reflect in heart morphology or physiology. These results might indicate that behavior profiles, unrelated to cardio-physiological performance, underlies the trait association between behavior reactions to novelty and swimming performance in the present study.

Wednesday 5 July 2023 POSTER SESSION

Mehwish Akram (University of Glasgow, United Kingdom), Andrew Gillen (University of Glasgow, United Kingdom), Shannon Keenan (University of Glasgow, United Kingdom), Julian A. Dow (University of Glasgow, United Kingdom), Shireen A. Davies (University of Glasgow, United Kingdom)

mehwish.akram@glasgow.ac.uk

Using computational meta-analysis of Drosophila data bases, we were able to identify sets of genes that showed strongly enriched expression in the four key alimentary epithelia (salivary gland, midgut, tubules, and hindgut). The hypothesis independent approach led to the functional analysis of Tetraspanin (Tsp) 29Fa/b in the core Drosophila epitheliome. In this study we discovered that Tsp29Fa/b is necessary for the integration of Disc-Large (Dlg) protein in smooth septate junction in the malpighian tubules. The depletion of Tsp29Fa lead to significant decrease in the secretory rates of the tubules. Furthermore, we discovered that Tsp29Fa/b is necessary to maintain the pH specific regions of the midgut in Drosophila as well.

A13.69 ENDOSOMAL TETRASPANIN 29FA/B IDENTIFIED BY DIGITTALLY AS AN INTEGRAL PART OF DROSOPHILA EPITHELIOME.

A13.68

A13.70 THE ROLE OF MED12 IN MALIGNANT GLIOMA TUMORIGENESIS

Wednesday 5 July 2023

POSTER SESSION

Stacey Glasgow (University of California San Diego, United States), Elizabeth Morozova (University of California San Diego, United States), Britta Sibley (University of California San Diego, United States), Desmond Richmond-Buccola (University of California San Diego, United States)

sglasgow@ucsd.edu

Glioma is the most prevalent and highly malignant form of adult brain cancer and is exceedingly difficult to manage. Neural stem cells and glial-determining factors have recently been implicated in glioma formation. Key transcriptional regulators of developmental gliogenesis are expressed in glioma and having functional roles during glioma tumorigenesis. Recently, we established that distinct chromatin conformations regulate expression of a key glial fate determining transcription factor, Nuclear Factor I-A (NFIA), to neuronal or glial lineages in the developing central nervous system. Further we found that the glial-specific chromatin architecture is also present in glioma and that disruption of this architecture can impede tumor formation in a mouse model of malignant glioma. Mediator complex subunit 12 (Med12) is an important transcriptional node that coordinates various aspects of development and gene expression. Med12 has been implicated in facilitating chromatin architectures in the transition from embryonic stem cells to neural stem cell. Our data show that Med12 associates with two transcription factors, Sox9 and Brn2, that are critical for the expression of NFIA and participates in chromatin looping of the Nfia locus. Moreover, deletion of Med12 in cortical astrocyte cultures compromises the integrity of the gliogenic loop structure resulting in decreased NFIA expression. Using a combination of in vitro assays and a novel mouse model of glioma that combines in utero electroporation with piggyBac-mediated transposons we find that Med12 is important for NFIA expression, tumor proliferation, and cell migration.

A13.71 KEEP THE PACE: LIFELONG EFFECTS OF TORPOR USE DURING DEVELOPMENT IN A SMALL HIBERNATOR

Wednesday 5 July 2023

POSTER SESSION

Sylvain Giroud (Research Instiute of Wildlife Ecology, Austria), Barbara Fux (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Sebastian Vetter (Institute of Animal Welfare Science University of Veterinary Medicine Vienna, Austria), Hanna Rauch-Schmücking (Institute of Animal Welfare Science University of Veterinary Medicine Vienna, Austria), Johanna Painer (Research Institute of Wildlife Ecology University of Veterinary Medicine Vienna, Austria), Steve Smith (Konrad Lorenz Institute of Ethology University of Veterinary Medicine Vienna, Austria), Sabine Lagger (Institute of Pathology University of Veterinary Medicine Vienna, Austria), Gerda Egger (Department of Pathology Medical University of Vienna, Austria), Caroline Gilbert (École Nationale Vétérinaire d’Alfort Laboratoire MECADEV, France)

sylvain.giroud@vetmeduni.ac.at

Torpor, or heterothermy, allows individuals to save energy via metabolic depression associated with hypothermia. Social thermoregulation can be combined with torpor, enabling individuals to minimize energy needs while maintaining relatively high temperature for growth. To date, little is known about developmental flexibility of heterothermy and how it relates to its expression later in life. In this study, we assessed torpor patterns of juvenile garden dormice (Eliomys quercinus) subjected to four distinct conditions,i.e., housed singly or grouped by four individuals, and provided with foodad-libitumor intermittentlyfasted. We determined epigenetic mechanisms after development and followed heterothermy expression later in life from individuals expressing different levels of developmental torpor; the highest (top third) or the lowest (bottom third) frequency, namely ‘high torpor’ (‘HT’) and ‘low torpor’ (‘LT’) respectively. We found that juvenile dormice use more frequent and longer torpor bouts when housed individually than in groups, and that torpor was stimulated by reduced food availability during autumn. We observed significant differences in mi-RNA levels regulating various metabolic pathways,e.g., substrate metabolism, redox status, or cancer in dormice according to their developmental torpor phenotype. Interestingly, HT dormice still displayed higher torpor frequency and longer torpor duration compared to LT individuals one year later (as subadults) irrespective of food intake. This significant difference in torpor phenotypes remained visible among two and threeyear-old dormice (adults) fedad-libitum, but not when intermittentlyfasted during autumn. We conclude that developmental torpor use in the garden dormouse determines, via epigenetic regulations, individual heterothermy expression later in life.

OF CARDIORESPIRATORY FUNCTION IN A NEOTROPICAL TELEOST, THE TRAHIRA (HOPLIAS MALABARICUS)

Wednesday 5 July 2023 POSTER SESSION

Igor N. Guagnoni (São Paulo State University (UNESP), Brazil), Vinicius A. Armelin (University of São Paulo (USP), Brazil), Victor H. S. Braga (São Paulo State University (UNESP), Brazil), Tobias Wang (Aarhus University (AU), Denmark), Luiz H. Florindo (São Paulo State University (UNESP), Brazil)

igornoll@hotmail.com

Fipronil is an insecticide that antagonizes ligand-gated ion channels of the gamma-aminobutyric acid (GABA) and glutamate receptors, which impedes chloride influx into cells and leads arthropods to death through neuronal hyperexcitation. Because of its low resistance potential and high toxicity to arthropods, fipronil is one of the most widely commercialized pesticides in the world. However, several studies have shown that fipronil is toxic to organisms beyond arthropods, such as fishes, promoting gill damage and disturbances in the animals’ normal redox state. Moreover, as GABA-regulated ion channels are widely spread in the central and peripheral nervous systems of ectothermic vertebrates, fipronil may impact the control of several physiological systems. In this context, we aimed to test the hypothesis that acute exposure to fipronil compromises fish cardiorespiratory function, by impairing mechanisms of short-term cardiovascular and respiratory regulation. For this, specimens of Hoplias malabaricus maintained in uncontaminated (control; N=5) and fipronil-contaminated water (96h

A13.72 EFFECTS OF ACUTE FIPRONIL CONTAMINATION ON SHORT-TERM REGULATORY MECHANISMS

at 0,5μg.l-1; Regent® 800WG; N=5) were instrumented with ventral aortic and buccal cannulas, allowing the evaluation of cardiorespiratory function and control (autonomic, baroreflex and chemoreflex control). Data were collected from undisturbed animals maintained in their respective water quality, under untreated condition, after muscarinic blockade with atropine (2mg.kg-1) and after double autonomic blockade with atropine and propranolol (2mg.kg-1). Our results demonstrate that fipronil contamination reduced the chemoreflex responsiveness, as well as parasympathetic cardiac tone and basal heart rate. Also, the contamination triggered cardiorespiratory synchrony, a mechanism that is presumed to increase oxygen uptake. Funding: grant 2020/14167-8, São Paulo Research Foundation (FAPESP).

A13.73 LONG-TERM SUSTAINED SWIMMING

IMPROVES SWIMMING PERFORMANCE IN CHINOOK SALMON ONCORHYNCHUS TSHAWYTSCHA WITH AND WITH SPINAL SCOLIOSIS

Wednesday 5 July 2023 POSTER SESSION

Leteisha A Prescott (University of Tasmania, Australia), Jane E Symonds (Cawthron Institute, New Zealand), Seumas P Walker (Cawthron Institute, New Zealand), Matthew R Miller (Cawthron Institute, New Zealand), Jayson M Semmens (University of Tasmania, Australia), Chris G Carter (University of Tasmania, Australia)

leteisha.prescott@utas.edu.au

Exercise training during early production is becoming a key component in salmon hatcheries as exercise enhances several production-related traits in salmonids. Exercise conditions for rearing salmonids are continually being optimised and now that the salmonid industry is developing offshore, training is being considered as a tool to prepare stocks for high energy environments. It is unknown if exercise can enhance traits in other understudied salmonid species and in individuals with spinal curvature, which is a common issue within some salmon farms. Here we exposed Chinook salmon to low (0.3 bl s-1) and moderate (0.8 bl s-1) tank velocities for ten to eleven months and quantified respiratory and swimming performance in individuals with and without mild scoliosis. Further, we investigated compositional and morphological responses at cellular and whole-body levels. Raising Chinook salmon under moderate velocities improved swimming performance in individuals with and without spinal curvature, but recovery processes in individuals with spinal curvature were greater. Fat content was reduced in fish raised under moderate velocities, while protein content was higher in individuals with spinal curvature. Together, the results of this study shows benefits for integrating exercise training into hatchery settings (i.e., pre- and post-smolts) to prepare stocks for offshore farming and provides evidence that some exercise-enhanced traits can be translated into individuals with spinal curvature, but concerns remain for individuals with more severe cases. Additionally, this study reveals that the product quality of fish farmed may change in offshore locations, and that optimising nutrient profiles for offshore feeds should be considered.

A13.74 HOMING PIGEON NAVIGATIONAL LEARNING: NO EVIDENCE THAT PASSIVE EXPOSURE TO A NOVEL RELEASE SITE IS SUFFICIENT FOR NAVIGATIONAL LEARNING

Wednesday 5 July 2023 POSTER SESSION

Joe Morford (Department of Biology University of Oxford, United Kingdom), Anna Gagliardo (Department of Biology

University of Pisa, Italy), Tim Guilford (Department of Biology

University of Oxford, United Kingdom)

joe.morford@biology.ox.ac.uk

Homing pigeons, the classic model species of bird navigation, navigate with an olfactory map and sun compass from unfamiliar areas. Conversely, in familiar areas, pigeons are largely guided by visual landmarks, following stereotyped and idiosyncratic routes. However, the mechanisms by which they gain familiarity with an area, learn to improve their navigation in familiar areas, and transition between navigational strategies during learning, are not fully understood. We investigated whether passive exposure to the cues at a site, without taking off, was sufficient for navigational learning, given that pigeons can determine the home direction before taking off, at both familiar and unfamiliar sites. We exposed pigeons to the cues available at a novel site, before returning them to the site the next day and releasing them, along with controls that had never previously visited the site. We found no differences in directional distributions, mean vector lengths, virtual vanishing times or homing efficiency indices between birds that had and had not previously been exposed to the release site. We therefore found no evidence to suggest that passive exposure to a novel release site was sufficient to facilitate an improvement in navigational performance. There are three possible explanations of this result: first, a larger sample size would have detected a small effect of learning on homing performance; second, passive exposure to a release site is insufficient to generate navigational learning; third, pigeons learn from passive exposure, but do not rely upon this information, showing no difference in performance, despite learning.

A13.75 ROLE OF THE NFIA TRANSCRIPTION FACTOR IN DEVELOPMENT OF SPINAL CORD MOTOR NEURONS

Wednesday 5 July 2023

POSTER SESSION

Julia Gauberg (University of California San Diego, United States), Sara Abumeri (University of California San Diego, United States), Alisa Salazar (University of California San Diego, United States), Kevin B Moreno (University of California San Diego, United States), Stacey M Glasgow (University of California San Diego, United States)

jgauberg@ucsd.edu

Even the most basic movements like walking or grasping require coordination of thousands of muscles throughout the body. The networks that coordinate body movements are located in the spinal cord, and an essential part of these networks are motor neurons that innervate skeletal muscles. Motor neuron differentiation, migration, and axonal targeting occurs during embryonic development and

defects in these processes can have severe effects on motor output and coordination in adult animals. However, the molecular mechanisms that regulate spinal motor neuron migration, especially late in vertebrate development, are not completely understood.

One essential part of motor neuron development is the spatial and temporal expression of DNA-binding transcription factors that regulate gene expression. A wide variety of transcription factors are expressed throughout vertebrate development and their combinations regulate neuron differentiation, migration, and axon projection. The Nuclear Factor IA (NFIA) transcription factor is a pivotal player during mouse brain and spinal cord development. Mice lacking NFIA die shortly after birth, with rare surviving animals exhibiting marked neurological defects, including lack of connection between brain hemispheres, tremor, and hydrocephalus. The role of NFIA in specifying the differentiation of spinal cord glia is well-established; however, the molecular mechanisms of NFIA function in neuronal populations is largely undetermined. Using conditional knockout mice, big data analysis, biochemical assays, and immunofluorescence staining our study reveals that NFIA plays an important role in spinal motor neuron migration during embryonic development.

A13.77 UNDERSTANDING THE GENETIC BASIS OF SEXUAL ANTAGONISM

Wednesday 5 July 2023 POSTER SESSION

Avishikta Chakraborty (University college london, United Kingdom), Max Reuter (University college london, United Kingdom), Aida Andres (University college london, United Kingdom)

avishikta0403@gmail.com

Wednesday 5 July 2023

POSTER SESSION

Hanna Scheuffele (Deakin University, Australia), Erica V Todd (Deakin University, Australia), John A Donald (Deakin University, Australia), Timothy D Clark (Deakin University, Australia) hscheuffele@deakin.edu.au

Global warming is leading to increases in the frequency and intensity of extreme weather events, magnifying the breadth of temperatures faced by ectotherms across days and seasons. Despite the importance and ecological relevance of diurnal thermal variability, the vast majority of knowledge on gene expression patterns and physiology stems from animals acclimated to constant temperatures. If heterothermal environments modulate responses differently from constant thermal environments, our existing capacity to forecast impacts of climate warming may be compromised. To address this knowledge gap, we acclimated barramundi (Lates calcarifer) to 23℃, 29℃ (optimal), 35℃ and to thermal cycling conditions (23-35℃ daily with a mean of 29℃) and sampled liver and white muscle tissue before acclimation and after 2 and 17 weeks of acclimation. NanoString nCounter technologies were used to measure expression of 20 genes related to metabolism, growth and maintenance of cellular homeostasis. Acclimation to cool and warm conditions caused predictable changes in wholeanimal performance (metabolism and growth) and underlying gene expression patterns. Acclimation to a cycling temperature regime did not change the molecular regulation of metabolism or growth compared with barramundi acclimated to constant 29℃, nor did it cause any discernible effects on whole-animal performance. However, the heat shock response was higher in the former group, suggesting that barramundi under a cycling temperature regime have an increased need for cellular chaperoning to minimise detrimental effects of temperature on proteins. The genetic regulation of metabolism and growth may be more dependent on the mean daily temperature than on the daily temperature range.

Sexual selection is a potent evolutionary force shaping a great diversity of phenotypes in animals and plants. Although sexes have a high degree of overlap in their genomes, the fitness-optima for several shared traits are sex-specific. Wherein traits increasing fitness in one sex may decrease fitness when expressed in the other. This can happen because some traits might be under strong sexual selection in males and not females. Opposing selection pressure on sexes often result in maintenance of genetic variants beneficial to one sex but not to the other, i.e., sexual antagonistic variants. There are several implications of sexual antagonism (SA); it plays an important role in maintenance of fitness variation, shapes immune responses, affects lifetime fitness and health. One of the key things that we lack understanding of is the genetic basis and the polymorphisms contributing to SA, and the way in which they affect organismal fitness. To identify SA polymorphisms, we use experimental evolution under sex-limited selection inD. melanogaster, coupled with computational analyses of genome-wide allele frequency trajectories to establish polymorphisms with significant SA effects and infer their evolutionary parameters (selection coefficient and dominance in both sexes). This will generate a catalogue of putative SA loci and tell us whether SA is caused by few strongly selected loci or a larger set of loci with small individual effects. Through this we aim to have a solid understanding of the genetic architecture of antagonistic genetic fitness variation and a well-defined set of SA loci for further study.

A13.78 THE EFFECT OF PERCEIVED RISK ON SLEEP BEHAVIOUR IN THE CARDINAL TETRA, PARACHEIRODON AXELRODI

Wednesday 5 July 2023 POSTER SESSION

Helena Norman (University of Glasgow, United Kingdom), Amelia Munson (University of Glasgow, United Kingdom), Daphne Cortese (University of Glasgow, United Kingdom), Shaun S Killen (University of Glasgow, United Kingdom)

2829921N@student.gla.ac.uk

Sleep is an evolutionary enigma; in a state of environmental disengagement, sleeping animals are unable to be vigilant towards threats, and temporarily forego processes such as foraging or mating. And yet, behavioural sleep is near ubiquitous across taxa. Studies show that biotic and abiotic factors can alter sleep architecture, for example, when perceived safety in the environment declines, animals favour vigilance behaviour over sleep. Understanding the ecological influences on sleep is vital, as sleep loss has the potential to affect waking behaviour and fitness. In fish, sleep deprivation has been found to cause cognitive and physiological impairments. However, the field of sleep in fish is relatively understudied and thus far, the role of

A13.76 DAILY THERMAL VARIABILITY DOES NOT MODIFY GENE EXPRESSION RELATIVE TO STABLE THERMAL ENVIRONMENTS: A CASE STUDY OF A TROPICAL FISH

environmental factors in shaping sleep architecture in fish is largely unknown. In this study, we investigated how group size and density, predator exposure and shelter availability affected the sleep duration and fragmentation in the cardinal tetra, Paracheirodon axelrodi. Fish were placed in groups of 2, 4 and 8, with either zero, intermediate or high shelter availability, and, were either exposed or not exposed to a predator model. Fish were filmed at night using infrared cameras, to determine the sleep architecture of P. axelrodi. The results of this study inform how fish alter their patterns of sleep in response to perceived risk from the environment, which is critical for understanding the ecological role of sleep and potential anthropogenic influences.

A13.79 INTRA-CELLULAR TRANSPORT SYSTEMS UNDERLYING CALCIFICATION IN THE SEA URCHIN LARVA: CURRENT KNOWLEDGE AND NEXT STEPS

Wednesday 5 July 2023 POSTER SESSION

Marian Y Hu (University of Kiel, Germany)

m.hu@physiologie.uni-kiel.de

To generate their skeletons, sea urchin larvae like many other marine calcifyers acquire carbonate ions that largely derive from the hydration of metabolic CO2. In this process protons are liberated that need to be removed from the calcification front to promote calcification and to defend cellular acid-base balance. Thus, biological calcification and pH regulation are intrinsically linked processes that remain relatively unexplored.

Using a wide range of techniques ranging from life cell imaging and intracellular pH recordings over protein-biochemical methods to molecular technologies our work identified a set of calcifying primary mesenchyme cell (PMC) specific ion transporters and channels that mediate a cytosolic carbon concentration mechanism (CCM) and removal of protons liberated by the calcification process. During skeleton regeneration pHi and intracellular HCO3 - levels are increased accompanied by a change in proton transport pathways. However, many calcifying organisms including the sea urchin larva produce amorphous calcium carbonate (ACC) within intracellular compartments. To date the mechanisms of carbon concentration and pH regulation in these calcification vesicles represents a black-box. Using the sea urchin larva as a model organism we aim to uncover these fundamental mechanisms of intracellular calcification. Knowledge about this process will help to understand how organisms manage to generate CaCO3 from a metabolic waste product – carbon dioxide. In this way, insights into the cellular calcification mechanisms may help to develop novel approaches for biology-inspired technologies to sequestrate carbon in times of rapid climate change.

Edward R Ivimey-Cook (University of Glasgow, United Kingdom), Winnie Boner (University of Glasgow, United Kingdom), Cara Cochrane (University of Glasgow, United Kingdom), Sophie M Dupont (University of Glasgow, United Kingdom), Neil Metcalfe (University of Glasgow, United Kingdom), Colin Selman (University of Glasgow, United Kingdom), Pat Monaghan (University of Glasgow, United Kingdom)

e.ivimeycook@gmail.com

Maternal age at breeding is known to influence a wide variety of offspring life history and fitness traits. One such example is the detrimental impact of advancing maternal age on the lifespan of offspring. This been shown with sufficient frequency across taxonomic groups to be known collectively as the Lansing Effect (LE). Whilst description of this phenomenon has been the focus of a significant body of mainly demographic research, the proximate cause(s) of the decline in offspring longevity is unclear. To identify these, we are using the vertebrate model organism, the zebrafinch (Taeniopygiaguttata),to investigate various measures of frailty, the increasing risk of death with age, in offspring from both young and old mothers. This includes how maternal age at breeding influences various age and sex-specific measures of flight performance, basal metabolic rate, mitochondrial function, telomere length and other parameters across the life course of their offspring. This will identify pathways through which the LE phenomenon can operate and whether it differs between male and female offspring.

A13.81 EVIDENCE FOR ENERGY REALLOCATION, NOT OXYGEN LIMITATION, DRIVING THE DECELERATION IN GROWTH OF ADULT FISH

Wednesday 5 July 2023 POSTER SESSION

Michael R Skeeles (Deakin University, Australia), Timothy D Clark (Deakin University, Australia)

michaelskeeles@gmail.com

Wednesday 5 July 2023

The lifetime growth of almost all fish follow a biphasic path – juvenile growth is rapid and adult growth subsequently decelerates. For a trend that is so ubiquitous, there is no general agreement as to the underlying mechanisms driving adult growth to decelerate. Ongoing debates argue that adult growth slows because either the gills fail to supply the body with surplus oxygen needed for continued somatic gain (i.e. oxygen limited) or because sexual maturation induces a switch in energy allocation towards reproduction and away from growth (i.e. energy limited). Here, we empirically tested these notions by tracking the individual growth trajectories of ~100 female Galaxias maculatus, ranging in size,during their first three months of adulthood. We provided subsets of fish with additional energy (fed once versus twice a day), supplementary oxygen (normoxia versus hyperoxia) or a combination of the two to assess if these are limiting factor(s) for adult growth. We found growth improved with additional energy, yet remained unaffected by supplementary oxygen thereby providing evidence for the role of energy in the deceleration of adult growth. Interestingly, the adult growth capacity of fish which matured at a larger size was weaker and more energy limited compared to smaller conspecifics, revealing size-dependent variances in energy acquisition and/or allocation budgets at summer temperatures. Overall, these experimental findings

A13.80 THE EFFECT OF MATERNAL AGE AT BREEDING ON SEXSPECIFIC OFFSPRING FRAILTY

THETAENIOPYGIA GUTTATA

contribute towards attaining a universal understanding of the drivers of adult growth in fishes - a critical step in understanding the body size responses of fish to climate warming.

A13.82 EFFECTS OF INJURY AND CADMIUM ON THE ENERGY STATUS IN THE EARTHWORM LUMBRICUS TERRESTRIS

Wednesday 5 July 2023

POSTER SESSION

Veronika Peer (Zoology, Austria), Gerhard P Aigner (Zoology, Austria), Birgit Fiechtner (Zoology, Austria), Martina Höckner (Zoology, Austria)

Veronika.Peer@uibk.ac.at

Environmental stress like injury or the exposure to toxic metals like Cadmium (Cd) are energy demanding processes. A previous study suggested that Cd detoxification is inhibited in injured earthworms, which could be due to limited energy sources. Hence, we examined in the present study different energy parameters in tissue of Lumbricus terrestris exposed to Cd with and without injury over a period of three weeks. The most prominent differences revealed the group of earthworms that were injured and at the same time exposed to Cd. We revealed significant changes in amp-activated protein kinase (pAMPK) levels, the main energy sensor of the cell as well as 70 kilodalton heat shock protein (HSP70), a molecular chaperone known to be involved in the innate immune response. Additionally, we measured glucose and protein levels, which changed significantly after one and two weeks, while after three weeks no significant differences could be observed between the treatment groups. We conclude that injured earthworms exposed to Cd have a higher energy demand than earthworms exposed to a single stressor. When we looked at injury and Cd exposure separately, we observed that these stressors caused different changes in pAMPK and HSP70 levels especially during the first week of treatment revealing stress-specific effects, which need to be further explored in future studies. However, we could not confirm the hypothesis that detoxification processes are inhibited in injured earthworms due to limitations in energy provision.

the worms in Wales (UK) has been known for some time, but is poorly defined. There is no existing dataset covering environmental conditions, such as, temperature, salinity, and light intensity, and how these likely influence population size. Additionally, no information on population genetics exists, e.g., intra-species gene flow or worm transfer between sites. For 12 months, we monitored such environmental conditions and population characteristics of worms at the Welsh field site. To establish whether these worms were distinct, we assessed the nucleotide diversity of the mitochondrial cytochrome c oxidase I subunit (COI) gene in gDNA extracted from worms across their known range (Wales, France, Portugal, Spain and Guernsey). Also, we targeted the 18S rRNA gene of the algal symbiont, Tetraselmis convolutae.

We observed shifts in environmental factors coinciding with fluctuating worm colony size and number. From genetic work, the worms present distinct haplotypes and ecotypes across locations, while the algal symbiont showed little genetic variation. Despite some genetic diversity among worm populations, the species of resident algal is constant, which likely reflects the evolutionary drive toward symbiosis in this host.

Wednesday 5 July 2023 POSTER SESSION

William W Chang (Institute of Physiology Kiel University, Germany), Angus B Thies (UCSD, United States), Martin Tresguerres (UCSD, United States), Marian Y Hu (Institute of Physiology Kiel University, Germany)

w.chang@physiologie.uni-kiel.de

A13.83

IN SITU ENVIRONMENTAL DRIVERS AND GENETIC COMPOSITION OF SYMSAGITTIFERA ROSCOFFENSIS SOUTH

WALES, UK

Wednesday 5 July 2023 POSTER SESSION

Nathan John Thomas (Swansea University, United Kingdom), Kam Tang (Swansea University, United Kingdom), Christopher Coates (University of Galway, Ireland)

944670@swansea.ac.uk

Known as the Roscoff or mint-sauce worm, Symsagittifera roscoffensis a marine flatworm distinguishable due to the presence of symbiotic algae (Tetraselmis convolute) residing beneath the epidermis. Isolated populations of S. roscoffensis span a broad geographically area, with many coastal sites along the Northeast Atlantic extending from Wales (UK) in the north to Portugal in the south. The single, field location of

Biomineralizing cells concentrate dissolved inorganic carbon (DIC) and remove protons from the site of mineral precipitation. However, the molecular regulatory mechanisms that orchestrate pH homeostasis and biomineralization of calcifying cells are poorly understood. Here we report that the acid-base sensing enzyme soluble adenylyl cyclase (sAC) coordinates intracellular pH (pHi ) regulation in the calcifying primary mesenchyme cells (PMCs) of sea urchin larvae. Single cell transcriptomics, in situ hybridization, and immunocytochemistry elucidated the spatio-temporal expression of sAC during skeletogenesis. Live pHi imaging of PMCs revealed that down-regulation of sAC activity with two structurally unrelated small molecules inhibited pHi regulation of PMCs, an effect that was rescued by addition of cell-permeable cAMP. Pharmacological sAC inhibition also significantly reduced normal spicule growth as well as spicule regeneration, establishing a link between PMC pHi regulation and biomineralization. In addition, increased expression of sAC mRNA was detected during skeleton re-mineralization and during exposure to CO2-induced acidification. Finally, we demonstrated that sea urchin sAC, similar as its mammalian homologs, carries the splicing variants that express only the catalytic domains, and expression analysis revealed that the re-mineralization process alters the abundance of sAC splicing variants potentially associated with the regulation of sAC activity. These findings suggest that transcriptional regulation of sAC is required to promote mineralization and compensate for acidic stress. The present work highlights a central role of sAC in coordinating acid-base regulation and biomineralization in calcifying cells of a marine animal.

A13.34 ACTIVITY OF SOLUBLE ADENYLYL CYCLASE IS REQUIRED FOR INTRACELLULAR PH HOMEOSTASIS AND BIOMINERALIZATION IN CALCIFYING CELLS OF SEA URCHIN LARVA.

A13.85 UNDERSTANDING THE FUNCTIONAL

BACKGROUND OF A

LIFE-

HISTORY GENE: WHAT WE CAN LEARN FROM AN EXPRESSION TIME-SERIES OF VGLL3, LHR AND AMH IN GONADAL TISSUES OF ATLANTIC SALMON (SALMO SALAR)

Wednesday 5 July 2023

POSTER SESSION

Eirik R Åsheim (University of Helsinki, Finland), Paul V Debes (Hólar University, Iceland), Andrew House (University of Helsinki, Finland), Petra Liljeström (University of Helsinki, Finland), Annukka Ruokolainen (University of Helsinki, Finland), Morgane Frapin (University of Helsinki, Finland), Iiki Donner (University of Helsinki, Finland), Ehsan P Ahi (University of Helsinki, Finland), Jaakko Erkinaro (Natural Resources Institute Finland, Finland), Jukka-Pekka Verta (University of Helsinki, Finland), Craig R Primmer (University of Helsinki, Finland)

eirik.asheim@helsinki.fi

Sexual maturation is a key process in the life-history of an organism. Variation in age at maturity can arise due to a combination of genetic and environmental aspects. In Atlantic salmon, alternative alleles at the gene vgll3 have been found to associate with differing ages at maturity, but the functional processes leading to this variation remain poorly understood. Knowledge of candidate gene expression patterns can contribute to understanding the functional pathway from genotype to phenotype. Until now, knowledge of the temporal expression pattern of vgll3 in developing gonads has been limited to one-year-old juvenile males, and a longer time series leading up to maturation has been entirely lacking in females. Here, we present a time series of gonadal vgll3 mRNA expression in male and female Atlantic salmon in a common garden setting, starting at the prepubertal stage and spanning multiple spawning seasons. We find that the pattern of reduced vgll3 mRNA expression in early-maturing males is also present in females. However, for the period leading up to the second spawning season, gonadal development was associated with an increase in vgll3 expression in males, and for females, an eventual decrease. Expression of vgll3 also had context-dependent correlations with expression of amh and lhr, and we found signs of vgll3 expression being negatively affected by a low-fat feed treatment in males. Overall, our results significantly widen the scope of our understanding of vgll3's temporal expression dynamics and give clues for candidate mechanisms for further research.

We previously described the potential role for a futile calcium cycling mechanism of endothermy in the heater organ of marlin (Makaira nigricans) as well as the red pectoral muscle of opah (Lampris incognitus). A futile calcium cycle can be the result of a leaky channel (RYR1) or an inefficient calcium pump (SERCA1) resulting in elevated ATP hydrolysis and heat production, a process termed non-shivering thermogenesis (NST). Sarcolipin (SLN), responsible for uncoupling of the SERCA1 pump is up regulated in the red pectoral muscles of the endothermic opah fish (Lampris incognitus). We analyzed transcript levels for sln and serca1 in skipjack (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares) and a closely related ectothermic scombrid fish species, bonito (Sarda chiliensis) as well as swordfish, a cranial endotherm. Sln and serca1 transcript levels are elevated in red muscle and eye muscle tissues for skipjack and yellowfin tuna but are not increased in bonito red muscle. Sln and serca1 transcript levels are not increased in swordfish heater organ tissue or red muscle. This observation is consistent with our original proposal that the futile calcium cycle in heater tissue is the result of a leaky RYR1 calcium channel. Recent studies in mammals support calcium leak through RYR1 as the primary regulatory factor in muscle thermogenesis. Just as endothermy has evolved independently in several vertebrate lineages, the causative basis for futile calcium cycling NST may be diverse as well.

A13.87 EVIDENCE OF PATERNAL PROTEIN PROVISIONING DURING MALE PREGNANCY IN THE SEAHORSE, HIPPOCAMPUS ABDOMINALIS

Wednesday 5 July 2023 POSTER SESSION

Zoe M. G. Skalkos (The University of Sydney, Australia), Sam N. Dowland (The University of Sydney, Australia), James U. Van Dyke (La Trobe University, Australia), Camilla M. Whittington (The University of Sydney, Australia)

Wednesday 5 July 2023 POSTER SESSION

Jens P C Franck (University of Winnipeg, Canada), Sean W M Robinson (University of Winnipeg, Canada)

j.franck@uwinnipeg.ca

Syngnathids (seahorses, pipefishes, and seadragons), are rare in that embryos develop on or in the male in a specialised brooding structure. Seahorse brood pouches provide post-fertilisation nutrients (patrotrophy) in the form of lipid transport during pregnancy. We tested the hypothesis that protein, vital for gene regulation and tissue growth during embryogenesis, is also transported to developing embryos during pregnancy in the Australian pot-bellied seahorse, Hippocampus abdominalis. We used dry masses and total nitrogen content to estimate total protein contents in recently fertilised embryo and newborn H. abdominalis. There was a significant increase in protein mass from recently fertilised embryos to neonates. The significant increase in protein mass over embryogenesis suggests that paternal protein transport occurs during H. abdominalis pregnancy. As protein yolk reserves are depleted by embryonic metabolism, paternal protein supplementation may be required. This study deepens our knowledge of the intimate relationship between developing embryos and the male placenta and furthers understanding of the paternal nutritional contribution to embryonic development in male pregnant vertebrates. Keywords:brood pouch, embryonic provisioning, nitrogen, parentotrophy,paternal investment, reproductionReferences [1]

Z. M. G. Skalkos, J. U. Van Dyke, C. M. Whittington, J. Comp. Physiol. B: Biochem. Syst. Environ. Physiol.,190547-556, (2020). [2] J. U. Van Dyke, O. W. Griffith, M. B. Thompson, Am. Nat.,184, 198-210, (2014).

A13.86 FUTILE CALCIUM CYCLE-BASED ENDOTHERMY IN FISH: LEAKY CHANNEL OR SLIPPING PUMP?

A13.88 THE POTENTIAL PROTECTIVE EFFECTS OF RESVERATROL AS A DIETARY SUPPLEMENT FOR TROPICAL FISH UNDER HEAT STRESS

Wednesday 5 July 2023

POSTER SESSION

Po Jui Hsu (Department of Laboratory Medicine Mackay Memorial Hospital, Taiwan), Min Chen Wang (Marine Research Station Institute of Cellular and Organism Biology Academia Sinica, Taiwan), Ling Chiu (Marine Research Station Institute of Cellular and Organism Biology Academia Sinica, Taiwan), Tzu Yen Liu (Marine Research Station Institute of Cellular and Organism Biology Academia Sinica, Taiwan), Hui Wen Peng (Marine Research Station Institute of Cellular and Organism Biology Academia Sinica, Taiwan), Yung Che Tseng (Marine Research Station Institute of Cellular and Organism Biology Academia Sinica, Taiwan)

ray60115@yahoo.com.tw

Climate change has increased the frequency of extreme weather and led to abnormal climate annual variation, especially having a major impact on aquaculture in East and Southeast Asia. The frequent temperature spikes in summer, which exceed the optimal range of the organisms, immune system disorders of organisms in tropical areas. Resveratrol (RSV) is a polyphenols compound that alters the pro-/anti-inflammatory activity against foodborne pathogens. In this study, we hypothesize that the RSV-supplemented diet can against bacterial infection and prevents the inflammation of aquaculture animals in summer. At first, the toxicity of RSV was tested in zebrafish embryos, and it revealed that RSV had no detrimental effects and did not affect their survival rate. And therefore, tropical tilapia (Oreochromis mossambicus) were used as test subjects to determine the effect of an RSV-supplemented diet on the fish gut microbial composition. The result of PacBio 16s rRNA sequencing indicates that RSV can reduce the potential pathogenic bacteria (AeromonasandPlesiomonas) and increase the abundance of probiotics (Cetobacterium) in the gut and gills of tilapia. In addition, using RSV to perform the minimum inhibitory concentration (MIC) test, we found RSV can inhibit pathogenic bacteriain vitro. Furthermore, we will investigate the effect of microbial on various physiological and immune responses of tropical fish after feeding RSV by the RNA-Seq analysis. Accordingly, the results indicated that RSV has the potential to serve as a valuable dietary supplement for tropical fish to cope with the frequent temperature spikes in summer, as a result of climate change.

typically occurs out of water to lower weight and overall costs, placing the crustaceans under significant metabolic stress as gas exchange becomes restricted due to gill collapse. Transport under these conditions can take between 5-24 hours leading to prolonged exposure to these stressors and increased morbidity and mortality upon arrival. Interventions which deliver metabolic suppression to live crustaceans during their transport have the potential to improve survival outcomes. Current approaches, such as cooling and the use of chemical anaesthesia, are either ineffective or costly, as such alternatives are needed. In an effort to decrease metabolic stress associated with transport the effects of three compounds (adenosine, theanine and isobutanol) were variously tested in three decapod crustacean species (The Malaysian freshwater prawn; Macrobrachium rosenbergii, New Zealand scampi; Metanephrops challengeriand the ornate tropical rock lobster; Panulirus ornatus). Adenosine and theanine in M. rosenbergiiand M. challengeri caused a transient decrease in heart rate during immersion and emersion while tissue and haemolymph metabolites (glucose, lactate and ammonia) remained unchanged. Isobutanol showed effectiveness at decreasing CO2 production during extended periods of emersion while reducing utilization of glycogen and the build-up of metabolic waste products inP. ornatus. Overall, the results show that adenosine and theanine may have limited applicability due to their rapid clearance, inconvenient administration and low efficacy. In contrast, isobutanol may be a promising metabolic suppressant and anaesthetic for crustaceans.

A13.90 INCUBATION IN HYPOXIA, 50% OF ATMOSPHERIC LEVELS, DAMPENS THE CARDIOVASCULAR RESPONSE TO ACUTE HYPOXIA IN JUVENILE AMERICAN ALLIGATORS, ALLIGATOR MISSISSIPPIENSIS

Wednesday 5 July 2023 POSTER SESSION

Dane A Crossley II (University of North Texas, United States), Janna L Crossley (University of Texas Southwestern, United States), Brandt Smith (University of North Texas, United States), Melissa Tull (University of North Texas, United States), Ruth Elsey (Rockefeller Wildlife Refuge, United States), Tobias Wang (Aarhus University, Denmark)

dane.crossley@unt.edu

Wednesday 5 July 2023 POSTER SESSION

Jaime R. Willis (University of Auckland, New Zealand), Andrew G. Jeffs (University of Auckland, New Zealand), Anthony J. R. Hickey (University of Auckland, New Zealand)

jwil497@aucklanduni.ac.nz

The movement of crustaceans as part of the seafood industry or for conservation can result in considerable mortalities. This transportation

We designed a series of studies to investigate whether 10% O2 over the course of incubation or from 20% to 50% of incubation affect cardiovascular function when juvenile American alligators reached an age of 4 to 5 years. At this age, we measured blood flows in all the major arteries as well as heart rate, blood pressure and blood gases in normoxia and two levels of acute hypoxia (10 and 5% O2). In general, acute 10% O2 exposure caused a decrease in blood oxygen concentration and an increase in heart rate, with limited effects on blood flow in the major outflow vessels of the heart. In response to acute 5% O2 exposure blood oxygen concentration also predicably decreased while heart rate increased as did blood flow in the right aorta, the subclavian artery, the carotid artery and the pulmonary artery however blood flow the left aorta either decreased or did not change. Embryonic exposure to hypoxia blunted the heart rate response to acute 10% O2 in juvenile animals. Further, the left aortic blood flow response to acute 5% O2 was not affected in juvenile animals that had experienced hypoxia throughout the majority of incubation. Alligators that had been incubated in hypoxia also had higher arterial PCO2 values in normoxia, suggesting a reduction in ventilation relative to

A13.89 INDUCIBLE METABOLIC SUPPRESSION: A SOLUTION TO STRESS ASSOCIATED WITH THE TRANSPORT OF AQUATIC CRUSTACEANS FOR INDUSTRY AND CONSERVATION?

metabolism. Future studies should seek to identify possible functional benefits of developmental phenotypic change caused by hypoxia on cardiovascular function in alligators.

A13.91 ANALYSIS OF LEADER-FOLLOWER RELATIONSHIPS OF SHOALING GUPPIES ACROSS TIMESCALES

Wednesday 5 July 2023 POSTER SESSION

Angela Albi (Max Planck Institute for Ornithology, Germany)

albi.angela@gmail.com

Social interactions play a critical role in shaping animal behavior, with the specific rules governing interactions having a profound impact on group behavior and decision-making. In some cases, decision-making involves a degree of leadership, which is a process of differential influence initiated by one or more individuals that results in behavioral change of other group members.

In this study, we analyzed two hours of data of 55 trials of eight freely shoaling guppies. We investigated how fish groups coordinate their activity and social cohesion by adjusting their speed, and how this level of organization varies across timescales of interactions. More specifically, we used time-shifted correlation analysis to quantify how individual-level speed/activity patterns vary over short and long timescales and how the degree of coordination with other shoal members shapes leader-follower dynamics.

Overall, we find that individual leadership scores for the short timescale are not predictive of who is the most influential individual over a long timescale. Additionally, we find that behavioral metrics that are commonly used to describe instantaneous kinematics (e.g. speed, acceleration, position within the group) positively correlate with leadership at the short timescale but lose this correlation over a longer timescale. These findings suggest that the mechanisms that govern leadership at the short timescale are likely different to those over the long timescale, and that common behavioral metrics might be insufficient to describe coordination and patterns over multiple temporal scales.

A13.92 THE METABOLIC CONSEQUENCES OF PREDATOR-INDUCED DEFENCES

Wednesday 5 July 2023 POSTER SESSION

Michaela Parascandalo (Monash University, Australia), Dustin J Marshall (Monash University, Australia), Matt D Hall (Monash University, Australia)

Michaela.parascandalo@monash.edu

Predator-induced defences are ubiquitous in biology. Prey are rarely passive in the presence of predators; instead, they express different phenotypes and behaviours to reduce their risks of predation. Such changes are thought to be costly – otherwise they would be expressed continuously to safeguard against unpredictable predator attacks. Here, we show that when exposed to predator cue, Dunaliella tertiolecta, a marine microalga, increases its metabolism by 25%. This metabolic response is significantly higher than that induced by nutrients. This increase in metabolism will have consequences for the carbon budget and demography of phytoplankton.

A13.93 TAURINE IMPROVES SKELETAL MUSCLE SENSITIVITY TO INSULIN IN OFFSPRING OF DIABETIC RATS

Wednesday 5 July 2023 POSTER SESSION

Nuntiya Somparn (Thammasat university, Thailand), Suphaket Saenthaweesuk (Thammasat University, Thailand), Atcharaporn Thaemor (Suranaree University of Technology, Thailand), Atcharaporn Somparn (Udon Thani Rajabhat University, Thailand)

nuntiya@tu.ac.th

Maternal diabetes is associated with defects in insulin receptor signaling this may be an important factor provoking maternal and fetal perinatal complications. Glucose transporter-4 (GLUT4), a one of the most important glucose transporters. The insulin regulated GLUT4 which is mainly expressed in skeletal and adipose tissues. It has been reported that perinatal taurine supplementation prevents diabetes mellitus in adult offspring of diabetic rats. In the present study, the effects of taurine on GLUT4 protein expression in muscle and adipose tissue were studied in the offspring of diabetic rats. Maternal diabetic rat model was established by a single intraperitoneal injection of streptozotocin (STZ) after 1 day of pregnancy. Taurine treated groups were received 3% taurine in drinking water during pregnancy and lactation. The male offspring from 4 dams (non-DM, non-DM+T, DM, DM+T groups) were studied at 4 weeks-age. Offspring from maternal diabetic rats displayed increased fasting blood glucose, decreased plasma insulin, and decreased GLUT4 protein expression (muscle and adipose tissue) compared to non-DM groups. In offspring from diabetic mother, perinatal treatment with taurine, significantly increased plasma insulin level and increase GLUT4 protein expression in muscle tissue whereas GLUT4 protein expression in adipose tissue were not altered compared with those from non-treated group. In conclusion,perinatal taurine supplementation increased GLUT4 expression in muscle tissue of offspring from diabetic mother, and this effect might be associated with increased plasma insulin level.

A13.94 THE BLACK DESERT BEETLE PARADOX REEXAMINED AND RESOLVED

Wednesday 5 July 2023 POSTER SESSION

Berry Pinshow (Ben-Gurion University of the Negev, Israel), Ella Agra (Ben-Gurion University of the Negev, Israel), Ariel Drabkin (Tel-Aviv University, Israel), Natanael Natanael (Gobabeb Namib Research Institute, Namibia), Thức Nguyễn Thị (Ben-Gurion University of the Negev, Israel), J. Scott Turner (State University of New York College of Environmental Science and Forestry, United States)

pinshow@bgu.ac.il

The black color of diurnal desert beetles has raised an enigmatic question because by being black the beetle would seemingly absorb much radiation and become very hot. Nevertheless, black coloration is quite common in desert animals and although many hypotheses have been proffered as solutions to the paradox and some empirical research done, there has been no unequivocal resolution. We reexamined the “black beetle paradox” by testing two predictions: 1) if the subelytral cavity functions as an insulating layer, a beetle’s operative (Te ) temperature will be lower than its surface temperature (Ts ); 2)

if beetle Te is coupled to convection, then posture (prone or stilted) will affect differences in Te temperature more than does size. We measured Ts and Te in 20 prone and stilting black tenebrionid beetles, Physadesmia globosa (large: five prone and five stilting; small: five prone and five stilting), a species abundant at Gobabeb Namib Research Institute. We made temperature measurements with (implanted micro thermocouples) of beetles in full sun and subsequently shaded to calculate time constants. The time constant (????) indicates the time it takes, after a change in conditions, for a beetle’s body temperature to approach a new Te . Our results confirm that the sub-elytral insulating layer and convection together combine to prevent black beetles from overheating in hot sunny deserts. We concluded that black coloration, in fact any surface color, has little effect on a beetle’s body temperature and the effect of size is negligible.

A13.95 THE EFFECT OF CONSPECIFIC PRESENCE ON INDIVIDUAL METABOLIC RATES: THE ROLE OF SPECIES’ SOCIAL SYSTEMS

Wednesday 5 July 2023

POSTER SESSION

Cheng Fu (University of Glasgow, United Kingdom), Shaun S. Killen (University of Glasgow, United Kingdom)

Cheng.Fu@glasgow.ac.uk

Group living offers advantages such as reduced predation risk and improved foraging and breeding opportunities, but also increases intra-species competition and the risk of parasitic infection. Hence, sociability, or the preference for group living, may vary among species and individuals based on their lifestyle and environments. In social species, it has been shown that the presence of conspecifics can reduce individual metabolic rates via a so-called “calming effect”. However, it remains unclear whether these effects differ among species with differing social systems. In this study, compared the effects of conspecifics on individual energy metabolism in two species: 1) the cardinal tetra (Paracheirodon axelrodi), a social schooling species; and 2) the dwarf cichlid (Apistogramma trifasciata), a species that is social but displays territoriality and dominance. We examined the metabolic rate of individuals both species under two conditions: alone and with three conspecifics. Additionally, we measured sociality by recording the average distance of experimental fish to three conspecifics or an empty area using a binary choice test. The results of this study will provide new insights into the benefits and costs of group living.

Sexual dimorphism is common among species, with some demonstrating more elaborate differences than others. Well known examples include the size seen in elephant seals and the elaborate plummages and songs exhibited by birds. Others species, including members of the order Scorpiones, exhibit only minor sexual dimorphism that is less noticeable. We investigated the degree of sexual dimorphism in the North American scorpion, Paruroctonus boreus, using scanning electron microscopy (SEM). Scorpions are solitary animals that only come together to reproduce. Mature males actively search for females during the mating season and use sensory organs, called pectines, to locate potential mates. Pectines are also used to locate suitable areas for spermatophore deposition. Consequently, these structures are thought to be under heavy selection pressure and exhibit sexual dimorphism. Four measurements from the pectines were used to assess sexual dimorphism across all body sizes. All measured variables were significantly different between adult males and females; however, no differences were found between juvenile males and females. These results suggest that P. boreus males develop larger sensory structures, through allometric growth, to facilitate reproduction. Behavioral observations corroborate the importance of pectines, to males, during reproduction. This highlights the role even a small structure may represent to its overall natural history.

A13.97 EFFECTS OF FOOD AVAILABILITY AND GROWTH VARIATION ON ONTOGENETIC METABOLIC SCALING IN ZEBRAFISH

Wednesday 5 July 2023

Alexander Rosén (National Institute of Aquatic Resources Technical University of Denmark, Denmark), Tommy Noren (National Institute of Aquatic Resources Technical University of Denmark, Denmark)

alero@aqua.dtu.dk

Wednesday 5 July 2023

POSTER SESSION

Abraham L Miller (University of Tampa, United States), Jennifer Fernandes (St. Petersburg College, United States)

abraham.miller@ut.edu

The steepness with which metabolic rate scales with body mass has been widely researched and debated due to its fundamental importance for size-dependent energetics and ecosystem dynamics. Little work has however been devoted to examining scaling on a within-individual (ontogenetic) level and what factors can affect this. Previous work has shown that variation in the steepness of ontogenetic scaling of standard (maintenance) metabolic rate (SMR) correlates with variation in growth rate among individuals of one species (brown trout) fed restricted, while the relationship was absent in another species (cunner) fed ad libitum. Thus, to understand if the relationship between ontogenetic metabolic scaling and growth rate is dependent on environmental food availability, we performed an experiment with 3 x 30 zebrafish kept individually from the larval stage to adulthood and fed low, medium, or high food rations. SMR and fish mass were repeatedly measured for all individuals as they grew, and ontogenetic metabolic scaling and growth rate calculated. While the experiment is still ongoing, our preliminary data suggest that there are substantial differences between ontogenetic scaling both within and between treatment groups. These differences are expected to become even more pronounced as the experiment finishes. A better understanding of what causes variation in how metabolic rate scales ontogenetically should help shed light on the variation in metabolic scaling that is observed at other levels of biological organization, such as across individuals or species, since natural selection works on individuals

A13.96

SENSORY STRUCTURES OF THE MALE SCORPION, PARUROCTONUS BOREUS, EXHIBIT ALLOMETRIC GROWTH AT MATURITY

SUPPORTING THEIR ROLE IN MATING.

A13.98 AMMONTELIC FISHES MAY HAVE DEVELOPED ENERGY-EFFICIENT STRATEGIES FOR BODY FLUID ION HOMEOSTASIS IN FRESH WATER

Wednesday 5 July 2023 POSTER SESSION

Pung-Pung Hwang (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Yung-Che Tseng (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Jia-Jiun Yan (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

pphwang@gate.sinica.edu.tw

Teleosts, one of the vertebrate groups initially invaded freshwater (FW) habitats, have to overcome the hypo-osmotic and more acidic environment (compared with seawater) by developing new machinery for ion uptake and acid secretion for their body fluid homeostasis. Ammonotelic teleosts excrete more ammonia than other vertebrate groups. Our serial studies found that teleosts appear to take the advantage of ammonia gradient to facilitate ion transport functions for body fluid Na+ and acid-base homeostasis. Teleost gills, similar to human kidney, excrete H+ and NH4 + for net acid secretion but relies more on NH4 + excretion to cope with internal or external acidic stress. Medaka (and most teleosts) mainly adopt Na+ /H+ exchanger (NHE)mediated NH4 + excretion, which is driven by the favorable ammonia gradient without consuming additional energy. Instead of developing the trait of H+ -ATPase driven epithelial Na+ channel (evolved in FW lamprey gills and frog skin), medaka takes the same advantage of ammonotelism to absorb Na+ mainly through NHE-mediated Na+ transport down the ammonia gradient. As such, the development of NHE-mediated Na+ /NH4 + exchange for internal Na+ and acid-base homeostasis exemplifies the selection of energy-efficient physiological traits in teleosts to accommodate for Na+ -poor and acidic situations in FW habitats during evolution.

A13.99 CYMBOPOGON CITRATUS PREVENTS FRUCTOSE-INDUCED DYSLIPIDEMIA IN RATS

Wednesday 5 July 2023 POSTER SESSION

ATCHARAPORN THAEOMOR (Suranaree University of Technology, Thailand)

thaeomor@gmail.com

In vitro experiments indicate that Cymbopogon citratus possesses antioxidant and anti-dyslipidemia activity. This study tests the hypothesis that Cymbopogon citratus prevents fructose-induced dyslipidemia in adult rats. Male Sprague-Dawley rats were fed normal rat chow and drank water alone (C), 10% fructose in water (F), 20% Cymbopogon citratus extract in water (CC) or 10% fructose plus 20% Cymbopogon citratus extract in water (FC) for 8 weeks. At 14 weeks of age, rats were collected blood samples. All data are expressed means ± S.E.M., compared by ANOVA, body weight, blood urea nitrogen (BUN), plasma creatinine (Cr), plasma aspartate aminotransferase (AST), plasma Alanine transaminase (ALT), plasma triglyceride and plasma high-density lipoprotein were not significantly different among the four groups. Compared to C group, high fructose intake (F group) significantly increased fasting blood, oral glucose tolerance test, plasma cholesterol

and plasma low-density lipoprotein. These fructose effects were all abolished by Cymbopogon citratus extract treatment (FC group). In addition, the Cymbopogon citratus extract treatment alone had no any significant effect on measured parameters. The present data indicate that Cymbopogon citratus extract prevents fructose-induced dyslipidemia in adult rats, likely by increasing lipid metabolism.

A13.100 ASSESSING HOW EXPLANT PROCESSING ALTERS BASELINE MOLECULAR PATHWAYS

Wednesday 5 July 2023 POSTER SESSION

Laura Oller (Abertay University, United Kingdom), Joel Rocha (Abertay University, United Kingdom), Ailsa Hall (St. Andrews University, United Kingdom), Kimberley Bennett (Abertay University, United Kingdom)

1704565@uad.ac.uk

Explants are becoming popular in wildlife research where no commercial cell lines are available. However, explants might naturally experience hypoxia and other molecular responses over incubation that can mislead our conclusions. It is unknown whether the initial manipulation of the tissue modifies the proteome and transcriptome. Here, we investigated if generating explants affects molecular pathways related to hypoxia and metabolism markers. Paired blubber biopsy samples from the dorsal flank of six weaned grey seal pups were taken. One biopsy was snap frozen; the other was prepared into explants, one of which was immediately snap frozen. The samples were analysed by qPCR and western blot, and statistically analysed with paired t-test/Wilcox test. Despite similar yield of total RNA between the snap frozen explant and the biopsy sample (p = 0.959), gene expression for Hif-1α (p = 0.046),Ppar-γ (p = 0.05), and Collagen VI (p = 0.031) were consistently and significantly lower in explants. Total protein was also significantly lower in explants (p = 0.002), but HIF-1α protein accumulation was not different (p = 0.313). Mitochondrial complexes I, II and III were not significantly affected by explant processing, but complex V was significantly depleted (p = 0.016). These findings suggest that explant processing introduces molecular shifts, maybe due to the mechanical disruption or changing the tissue composition by removing blood and fibrotic tissue. Further exploring responses across other pathways would be informative to evaluate if the baseline levels are representative of the in vivo microenvironment.

A13.101 DEVELOPMENT OF A PRIMARY CULTURED SEA LAMPREY (PETROMYZON MARINUS) GILL EPITHELIUM

Wednesday 5 July 2023 POSTER SESSION

Chun Chih Chen (York University, Canada), Michael P Wilkie (Wilfrid Laurier University, Canada), Scott P Kelly (York University, Canada)

chunchih.chen@mail.utoronto.ca

Primary gill cell culture techniques have contributed to our understanding of gill epithelium physiology in various fish species, allowing transport (particularly paracellular transport) studies to be conducted on an otherwise architectural complex organ. This study

reports on the development of a primary cell culture technique using larval sea lamprey (Petromyzon marinus) gill cells and gill explants to establish a lamprey gill epithelium model in both tissue culture wells and on permeable cell culture insert supports. Gill explant outgrowth on tissue culture plates produced an epithelium coverage area (up to and after ~20 days in culture) of ~10 mm in diameter. In cell culture inserts, explant outgrowth was sufficient to cover inserts with a growth area of 0.3 cm2 , and these epithelia generated a background corrected transepithelial electrical resistance (TER) plateau of ~600 Ω·cm2 . Molecular profiling of cultured preparations revealed transcripts of tight junction (TJ) assembly proteins that included claudin (cldn) -3b, -18, and -19, as well as occludin-a (ocln-a) and tricellulin (tric). Transcript encoding other genes (cldn-10 and ocln) which are present in whole gill tissue were absent from the cultured preparation. Western blotting verified the presence of Ocln-a in the cultured epithelium. The response of cultured preparations to 11-deoxycortisol (0, 1 and 10 ng/mL) was found to elicit a transient effect on TER at a high dose only. The current work provides a model gill epithelium for studying basal vertebrate (agnathan) branchial functions and some insight into the molecular physiology of the lamprey gill epithelium TJ complex.

A13.103 REPEATABLY DISTINCT REPRODUCTIVE PROFILES OF CLONAL FISH RAISED IN IDENTICAL ENVIRONMENTS AND THEIR RELATIONSHIP TO EARLY-LIFE BEHAVIOURAL INDIVIDUALITY

Wednesday 5 July 2023 POSTER SESSION

Ulrike Scherer (Science of Intelligence Excellence Cluster, Germany), Sean M. Ehlman (Science of Intelligence Excellence Cluster, Germany), David Bierbach (Science of Intelligence Excellence Cluster, Germany), Jens Krause (Science of Intelligence Excellence Cluster, Germany), Max Wolf (Science of Intelligence Excellence Cluster, Germany)

u.k.scherer@gmail.com

A13.102 SEX-SPECIFIC

MOLECULAR PHYSIOLOGY OF THE POECILID GILL EPITHELIUM TJ COMPLEX

Wednesday 5 July 2023

POSTER SESSION

Eleni Diakanastasis (York University, Canada), Helen Chasiotis (York University, Canada), Scott P Diakanastasis (York University, Canada)

elenid@my.yorku.ca

Poeciliids are a sexually dimorphic family of livebearing fishes, many members of which exhibit a high degree of physiological plasticity. This study considered the sex-specific molecular physiology of the gill epithelium tight junction (TJ) complex ofPoecilia wingei(Poeser, Kempkes & Isbrücker, 2005), in response to salinity. Claudin (Cldn) TJ proteins known to exhibit abundance in the gill epithelium, and some degree of sensitivity to salinity change were targeted. Fish were acclimated to either freshwater (FW) or salt water (SW, ~32‰) for two weeks and gill was collected for analysis ofcldnmRNA abundance. Data was examined either (1) collapsed (i.e. combined results for male and female fish) or (2) separately (i.e. male and female fish independently). Collapsed data indicated that manycldnsaltered in response to salinity (i.e. elevatedcldn-8d, -10d, -10e, -10f, -28a, -28b, -28cor reducedcldn-3b, -3c, -3dmRNA levels). However, it was observed that some of these changes were driven by one sex only. For example, a salinity-induced elevation incldn-8dandcldn-28amRNA abundance was driven by changes in the gill of female fish only. In addition, the mRNA abundance ofcldn-3dand-8cwere found to differ between the gill of male and female fish irrespective of salinity. This study suggests that sex-specific differences in the molecular physiology of the gill TJ complex occurs inP. wingeiand that these may be present independent of salinity change or may only occur when fish are exposed to altered environmental conditions.

According to a long-standing paradigm, genetic and environmental differences are the key drivers underlying behavioural variation. Recently, however, this paradigm has been experimentally challenged, finding that substantial among-individual variation emerges even in the absence of those differences. But does such variation matter? Here, we tested if (i) individuality that emerges under highly standardized conditions extends to aspects of the phenotype that directly affect fitness: the size and number of offspring produced over consecutive broods. We further ask if (ii) reproductive individuality is indicative of differences in life-history productivity and if (iii) there is a link to early-life behavioural individuality (activity, feeding behavior). We performed a tightly controlled long-term life-history experiment with 34 naturally clonal fish,Poecilia formosa, separated at birth and reared under identical conditions for 280 days. We characterized early-life behavioural profiles (all individuals were recorded daily for 10 hours, over the first 28 days of life) and measured the complete reproductive profiles of individuals, quantifying in total 2522 offspring from 152 broods. (i) We find that individuals differ consistently in the size of offspring and broods produced. (ii) These differences are observed even when controlling for the brood vs. offspring size tradeoff, indicating that individuals differ in life-history productivity. (iii) Early-life individuality in feeding is indirectly linked to reproductive output: individuals that feed more become larger and larger individuals produce larger offspring. Our findings provide experimental evidence that processes unrelated to genetic and environmental differences can have long-lasting effects on aspects of the phenotype that directly affect fitness.

A13.104 TAURINE SUPPLEMENTATION PREVENTS INSULIN-GLUCOSE DYSREGULATION IN PREGNANCY WITH DIABETES MELLITUS RATS

Wednesday 5 July 2023 POSTER SESSION

Suphaket Saenthaweesuk (Thammasat University, Thailand), Nuntiya Somparn (Thammasat University, Thailand), Thanaphon Srimueang (Khon Kaen University, Thailand), Atcharaporn Thaeomor (Suranaree University, Thailand)

suphaket18_s@hotmail.com

This study evaluated the effect of taurine supplementation on insulin secretion in pregnancy with diabetes mellitus rats. Female Wistar rats were fed normal rat chow and tap water with (Diabetes group) or without diabetes induction by intraperitoneal streptozotocin injection (50 mg/kg of body weight) (Control group) before pregnancy. Then, they were supplemented with 3% taurine in water (Control+T and Diabetes+T groups) or water alone from conception to weaning. After weaning, fasting blood sugar (FBS), oral glucose tolerance test (OGTT), plasma insulin level, insulin resistance, and blood lipid profiles were measured in maternal rats. All data are expressed means ± S.E.M., compared by ANOVA,. Body weight, total cholesterol, high-density lipoprotein, lowdensity lipoprotein and insulin resistance (estimated by HOMA-IR) were not significantly different among the four groups. Further, compared to maternal control, the maternal with diabetes group displayed significant increases in fasting blood sugar, and plasma triglyceride, but a decrease in plasma insulin, pancreatic weight and pancreatic to body weight ratio. Taurine supplementation in drinking water significantly improved, at least in part, these adverse effects of maternal with diabetes mellitus (the Maternal with Diabetes+T compared to other groups). These data suggest that taurine supplementation affects pancreatic growth and insulin-glucose homeostasis in pregnancy with diabetes mellitus rats.

A13.105 EVALUATING RNA QUALITY

Wednesday 5 July 2023

POSTER SESSION

Alexandra Tranganida (University of Aberdeen, United Kingdom), Joanna L. Kershaw (University of Aberdeen, United Kingdom), Davina Derous (University of Aberdeen, United Kingdom)

a.tranganida.22@abdn.ac.uk

Omics applications (e.g., transcriptomics) are powerful tools to investigate animal physiology. Applying these techniques in marine mammal research is limited in part due to the challenges of collecting high quality samples. Sampling sites are often far from laboratory settings, and it is particularly important that samples are collected and preserved appropriately to minimise molecular degradation. Using tissues from stranded animals is an invaluable tool to gain insight into the challenges free-ranging animals face, including humancaused disturbances. There is lack of information on the suitability of samples from stranded marine mammals in ‘omics studies. Tissues may degrade or undergo post-mortem metabolic changes by the time a stranding is reported. However, research in model organisms suggests there is scope for using targeted ‘omics approaches in samples collected post-mortem, as long as tissue-specific molecular changes are accounted for. Here, we evaluated the impacts of time since death and sample storage conditions on blubber RNA quantity and quality for downstream applications. Blubber samples (n=15) were collected over the course of 24 hours from a freshly stranded grey seal (Halichoerus grypus) stored outside, at ambient temperature (4-6o C). Samples were either: 1) preserved in RNA stabilising buffer, 2) flash frozen using liquid nitrogen, or 3), stored at -80o C directly with no prior preservation method. Total RNA was extracted using a standard phenol–chloroform protocol. Preliminary results show that sufficient yields and intact RNA can be obtained approximately eight hours post-mortem, as determined by spectrophotometry and gel electrophoresis. This study provides vital methodological validation for future research.

A13.106 WHY DO FISHES CLOSE THEIR OPERCULUM? THE RELATIONSHIP BETWEEN THE OPERCULAR OPENCLOSE MOVEMENT AND ENVIRONMENTAL FACTORS.

Wednesday 5 July 2023 POSTER SESSION

Kosuke Matsuda (The University of Tokyo, Japan), Ryo Kawabe (Institute for East China Sea Research Organization for Marine Science and Technology Nagasaki Univ, Japan), Takaaki K Abe (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Kentaro Q Sakamoto (Atmosphere and Ocean Research Institute The University of Tokyo, Japan), Katsufumi Sato (Atmosphere and Ocean Research Institute The University of Tokyo, Japan)

matsudako625@g.ecc.u-tokyo.ac.jp

The gills of fishes play an important role in respiration and thermoregulation through the exchange of oxygen and heat in the water. As the exchanges on the gills are passive processes, it is widely believed that fishes adjust the amount of water flowing through their gills according to external and internal conditions. However, the extent to which fishes actually regulate the ventilation of their gills in response to various conditions in nature remains largely unknown. To explore this question, we investigated via biologging technics the opening and closing movement of the operculum and their relationship to environmental factors in free-swimming marlins (striped marlin Kajikia audax and sailfish Istiophorus platypterus), which have large operculum and gill lamellae. Instrumental packages containing animal-borne video cameras and behavioural data loggers were deployed on the base of the dorsal fin of marlins. The video cameras recorded the opercular movements of marlins. The data loggers monitored depth, water temperature, and swimming speed. Through the detailed analysis of video and behavioural data, we found that the degree of gill opening was affected by physiological and environmental factors. The Marlins opened their gills wide for a while after release, but the degree of opening decreased over time. The degree of gill opening also decreased if marlins dived to deep or experienced cold water, suggesting that gill ventilation was reduced to maintain body temperature. The present study provides new insights into the regulation of gill ventilation by fish to cope with physiological and environmental changes in nature.

A13.107 THE INFLUENCE OF HYPOXIA ON THE OXIDATIVE STATUS AND MITOCHONDRIAL DYNAMIC IN THE SKELETAL MUSCLE OF THE GOLDFISH CARASSIUS AURATUS

Wednesday 5 July 2023 POSTER SESSION

Alessia Caferro (University of Calabria, Italy), Mariacristina Filice (University of Calabria, Italy), Alfonsina Gattuso (University of Calabria, Italy), Maria C Cerra (University of Calabria, Italy), Sandra Imbrogno (University of Calabria, Italy)

alessia.caferro1@gmail.com

In the goldfish Carassius auratus, a teleost model of hypoxia resistance, exposure to hypoxia is accompanied by a significant improvement of

IN BLUBBER COLLECTED WITHIN 24 HOURS SINCE DEATH IN A MARINE MAMMAL: IMPLICATIONS FOR ‘OMICS APPROACHES

the swimming performance, expressed by a higher critical swimming speed, and a lower cost of oxygen transport. Based on these data, and since very limited information is available on the molecular mechanisms that sustain the responses of the goldfish skeletal muscle to hypoxia challenges, we evaluated the oxidative status, the expression of stress proteins (HSP70 and HSP90) and the mitochondrial dynamic in the skeletal muscle of goldfish exposed to 4 and 20 days of hypoxia. Results showed that the oxidative status is not affected by both 4 and 20 days of low oxygen availability. This is revealed by no changes in lipid peroxidation and protein carbonylation. Contrarily, a decreased SOD activity was observed after short hypoxia. In parallel, after 4 days of hypoxia, a selective activation of HSP70, but not of HSP90, was detected. By Western Blotting, an increased expression of mitochondrial abundance markers (i.e., VDAC and cytocrome c), as well as of factors involved in mitochondrial biogenesis (PGC-1, NRF-2, and Tfam) was observed in muscle homogenates of hypoxia-exposed fish. Although preliminary, these results reveal new aspects of the molecular mechanisms activated in the goldfish skeletal muscle in response to hypoxia which may contribute to its correct functionality even in conditions of prolonged exposure to low oxygen levels.

A13.108 RESOURCE MANAGEMENT IN NIGERIA'S PROTECTED AREAS: PROMOTING INDIGENOUS KNOWLEDGE PRACTICES

Wednesday 5 July 2023 POSTER SESSION

Samson O. Ojo (University of Ibadan, Nigeria),

Olusina T. Ajayi (Federal College of Animal Health Production Technology, Nigeria)

gbemiga_ojo@yahoo.co.uk

Nigeria's protected areas (PAs) are greatly endowed with several flora and fauna species. Some of the PAs in Nigeria are Old Oyo National Park, Jos Wildlife Park, Omo Forest Reserve, Dagona Birds Sanctuary and Sabon Wuse. There are evidences that almost all the PAs in the country are negatively impacted by indiscriminate human activities such as hunting, fishing, bush burning, herd grazing, etc.

This study investigated the indigenous knowledge of the residents in the host communities of selected PA. Key informant interviews (KII) were conducted among randomly selected resource-users. The findings showed that traditional belief systems have strong elements that can be adopted and integrated into conventional model for resource management and conservation. Seventy percent of the participants opined that totemism should be adopted because some totem plant and animal species have been preserved while 60% spoke about the value of sacred grooves in the pre-colonial era. In addition, 40% of the participants, opined that their IK had helped them in making decisions on natural resources management. Furthermore, one of them, a hunter, reported that IK had proven its ability to contribute to the sustainability of many ecological systems. It is therefore recommended that indigenous knowledge of local people be promoted in resource conservation considering the immense contributions of such knowledge to the relationship between communities and their immediate environment

A13.109 EFFECTS OF TAURINE SUPPLEMENTATIONS WITH EXERCISE ON ANTIOXIDANT ENZYME ACTIVITIESIN MIDDLE-AGED RAT BRAINS

Wednesday 5 July 2023

POSTER SESSION

Rungrudee Srisawat (School of Preclinical Sciences Institute of Science Suranaree University of Technology, Thailand), Jiraporn Onsri (School of Preclinical Sciences Institute of Science Suranaree University of Technology, Thailand)

srisawat@sut.ac.th

Age-related increase in oxidative stress plays a key role in cognitive decline. Regular exercise and an essential amino acid Taurine supplementation are effective against the progression of oxidative stress in age-related degenerative changes. Thus, this study investigated the effects of taurine with exercise on antioxidant enzyme activities in middle-aged rat brains. Male rats (15 months old) were divided into sedentary and swimming exercise groups. Rats received water, 1% tween-80, vitamin E (50 IU/kg), or taurine (800 mg/kg) for 8 weeks. Antioxidant enzymes (SOD, CAT, and GPx) activities in the basal forebrain, cerebral cortex and hippocampus were determined. Exercise significantly increased GPx activity levels in the basal forebrain, compared to the sedentary group. In the sedentary group, taurine significantly increased SOD levels in basal forebrain and GPx activity levels in the hippocampus, compared to the control group. In the exercise group, taurine significantly increased SOD levels in the cerebral cortex, CAT and GPX activity levels in the hippocampus, and CAT and GPX activity levels in the basal forebrain, compared to the control group. Taurine supplement in conjunction with exercise significantly increased CAT and GPX activity levels in the hippocampus, compared to taurine supplementation in the sedentary group. Taurine supplement in conjunction with exercise is capable of reduction of oxidative stress and enhancement of antioxidant enzymes activities in middle-aged rat brains. Therefore, taurine supplements in conjunction with exercise may benefit in the reduction of oxidative stress which is contributed to age-related neurodegenerative diseases.

A13.110 GENETIC ADAPTATION IN COMMON MOLE-RATS (CRYPTOMYS HOTTENTOTUS HOTTENTOTUS) ALONG AN ARIDITY GRADIENT

Wednesday 5 July 2023

POSTER SESSION

Hana N. Merchant (Royal Holloway University of London, United Kingdom), Anastasiia Ivanova (Queen Mary University of London, United Kingdom), Daniel W. Hart (University of Pretoria, South Africa), Nigel C. Bennett (University of Pretoria, South Africa), Chris G. Faulkes (Queen Mary University of London, United Kingdom), Steven J. Portugal (Royal Holloway University of London, United Kingdom)

phba013@live.rhul.ac.uk

Genetic adaptation is the progressive change of a population towards a phenotype which best fits the present ecological conditions in which it lives. As environmental conditions change, allele frequencies shift, leading to different populations of the same species having genetic variation and divergent phenotypes. Cooperatively breeding common

mole-rats (Cryptomys hottentotus hottentotus) inhabit environments along an aridity gradient in South Africa, which provides opportunity for local genetic adaptations. This study aims to determine population differences through the exploration of genome wide SNPs. Using a targeted bait capture technique, we will map and compare the highly variable flanking regions of Utraconserved Elements (UCEs). By looking at genome wide differences, we will reveal candidate loci underlying adaptive traits or expression control. Differences in the frequencies of these loci among populations may infer evolutionary patterns within a species, and reveal conserved and divergent aspects of function, regulation, and evolution. Preliminary genetic assessment of the populations using mitochondrial Cytochrome b sequence analysis reveals some population genetic structure. Mesic populations formed monophyletic clades distinct from the arid populations. In the latter, population-specific clades were less well defined potentially indicating historical or recent geneflow, or the retention of ancestral haplotypes. Our further analysis to determine if there are differing underlying genetic adaptations among populations of C. h. hottentotus will help us to understand population differences in physiological plasticity within a single species of Bathyergid mole-rat.

A13.111 PARENTAL CONTROL OF OFFSPRING MICROBIOTA IN AEDES AEGYPTI MOSQUITOES

Wednesday 5 July 2023

POSTER SESSION

Mathilda J Whittle (Macquarie University, Australia), Fleur Ponton (Macquarie University, Australia), Sinead English (University of Bristol, United Kingdom), Antoine M. G Barreaux (CIRAD, France), Michael B Bonsall (Univeristy of Oxford, United Kingdom)

mathildawhittle@gmail.com

The fitness of animals is often dependent on the composition of their gut microbiome. The gut microbiome of mosquito larvae is acquired horizontally from the aquatic environments in which they hatch, and the presence of beneficial bacteria in larval habitats is therefore crucial for successful development to adulthood. We hypothesise that female mosquitoes exert a degree of control over the gut microbiota of their juvenile offspring via oviposition site selection. We test this hypothesis by i) culturing and identifying bacteria associated with a lab colony of Aedes aegypti; ii) rearing gnotobiotic A. aegypti larvae in substrates containing different strains of bacteria to determine which strains and communities best promote larval development; and iii) conducting a choice experiment where the same substrates are offered to gravid females to determine oviposition site choice preferences. We anticipate that gravid female mosquitoes preferentially lay their eggs in substrates containing the bacterial communities which promote the developmental success of their offspring. Our study aims to highlight breeding site selection as a link between horizontal and vertical transmission of microbiota.

A13.112 PHYSIOLOGICAL AND BEHAVIOURAL VARIATION ACROSS FIVE SPECIES OF CRYPTOBENTHIC FISHES

Wednesday 5 July 2023 POSTER SESSION

Madison Schumm (The University of Texas at Austin Marine Science Institute, United States), Andrew Esbaugh (The University of Texas at Austin Marine Science Institute, United States), Chris Goatley (University of Southampton, United Kingdom), Simon Brandl (The University of Texas at Austin Marine Science Institute, United States)

mschumm7@utexas.edu

Cryptobenthic fishes are a highly diverse group of small-bodied (<5 cm) fishes that form tight associations with reef habitat and play a critical role within coral ecosystems as an abundant link between high and low trophic levels. They are generally subject to high rates of predation with short generation times that have enabled rapid diversification. However, the role of niche partitioning as a contributor to diversification by facilitating co-existence through habitat specialization is not well characterized. The aim of this study was to assess the potential role of niche partitioning in the diversification of cryptobenthic fishes by comparing metabolic and behavioural trait variation across Eviota spp. and the potential linkages to microhabitat specialization. Five species of Eviota gobies were collected from the Great Barrier Reef in Australia and evaluated for standard and maximum metabolic rates, as well as two separate behavioural traits. Preference for dark vs. light substrate (i.e. scototaxis), which is used as an indicator of predation-related anxiety, was tested using a scototaxis assay. A habitat choice test presented individual fish with five novel objects that represent distinct habitat types available in a coral reef. Our data show species differences in both standard and maximum metabolic rate, which translate to differences in aerobic scope. Behavioural data also suggest that different species express varying habitat preferences and anxiety/risk-taking behaviours. Overall, our study supports the hypothesis that niche partitioning on the basis of physiological and behavioural traits has contributed to the diversification of Eviota spp. on the Great Barrier Reef.

A13.113 AQUATOURISM POTNTIALS OF IKERE GORGE DAM, OYO STATE, NIGERIA

Wednesday 5 July 2023 POSTER SESSION

Samson O. Ojo (University of Ibadan, Nigeria)

gbemiga_ojo@yahoo.co.uk

Aquatic tourism potentials of Ikere gorge was done.

Fish catches collected from two landing sites fortnightly for 24 months, abundance and diversity done, sorted into families, species and use (ornamental and food) based on morphometric and meristic features. Water done using standard procedures. One set of structured questionnaires were administered to 350 visitors for patronage interest. Data were analysed using Shannon and Simpson indices, descriptive statistics, t-test and ANOVA at p=0.05.

Mean capture per unit effort was 0.5+0.1 kg per fisherfolk per hour. Thirty-four fish species belonging to 13 families, food/ornamental fish ratio: 757%:24.3%. Families were: Bagridae (9.45%), Cichlidae (52.25%), Characidae (5.45%),Claridae (2.2%),Centropomidae (1.35%),Cyprinidae(3.9%),Hepsetidae(0.95), Schilbeidae(3.25%, Mormyridae(17.55%), Mockokidae(0.9%), Osteoglossiadae(1.55%), Channidae(0.9%) and Tetraodontidae(0.3%). Dominant ornamental species in Year1 were Pelmatochromis guenther(27.8%), Macusenius psittacus(21.2%) and Synodontis nigrita(20.39%) while Tilapia mariae(29.3%), Macusenius psittacus(26.8%) and Synondontis menbraneous(18.3%) were dominant in Yr2. Common food species

in Year1 were Lates niloticus(6.3%), Mormyrus rume(6.2%) and Mormyrus deliciousis(4.3%). Shannon index in Year1 (2.9) was less than Year2 (3.1) and Simpson's index of 0.9 signified species richness. Average physico-chemical parameters of the dam were: temperature (29.0+0.5 °C), DO (8.9+1.1 mg/L), transparency (64.0+8.8 cm), conductivity (255.6+3.7 µ/cm), TDS 29 (192.3+0.9 g/L) and pH (7.2+0.3). Patronage interest: educational, recreational and countryside viewing. Natural attractions and pristine environments all encouraged visitors’ willingness, Fish species richness, facilities and natural endowments, high visitors patronage interest established the suitability of Ikere Gorge dam as a potential tourist site.

A13.114 EVOLUTION OF REPRODUCTIVE SUCCESS IN A CHANGING CLIMATE

Wednesday 5 July 2023

POSTER SESSION

Patrice Pottier (The University of New South Wales, Australia), Dougherty M. Liam (University of Liverpool, United Kingdom), Vasudeva Ramakrishnan (University of East Anglia, United Kingdom), Natalie Pilakouta (University of Aberdeen, United Kingdom), Mads F. Schou (Lund University, Sweden), Stefan Lüpold (University of Zurich, Switzerland), Pedro Simões (University of Lisbon, Portugal), David Berger (Upssala University, Sweden), Berta Canal Domenech (Universität Münster, Germany), Benjamin Cole (University of East Anglia, United Kingdom), Erik Svensson (Lund University, Sweden), Steve Ramm (University of Rennes, France), Marco Graziano (University of East Anglia, United Kingdom), Abhishek Meena (University of Zurich, Switzerland), Cristina Tuni (University of Turin, Italy), Szymon Drobniak (The University of New South Wales, Australia), Shinichi Nakagawa (The University of New South Wales, Australia)

p.pottier@unsw.edu.a

Changing temperature regimes have important impacts on the reproductive success of ectothermic species by altering fecundity and offspring quality. However, the potential for reproductive success to evolve in response to environmental change remains elusive. Importantly, changing temperatures may impact reproductive success by affecting trade-offs between fecundity and offspring quality. In addition, changes in trait variance may prove pivotal in facilitating or hampering adaptation to changing environments. Here, we systematically reviewed experimental evolution studies quantifying ectotherm responses to warming and cooling. We used a meta-analytic approach to investigate how the mean and variance in fecundity and offspring quality (body size and viability) evolve in response to changing thermal environments. We also assessed correlations between fecundity and offspring quality to highlight potential trade-offs in the thermal evolution of these traits. Our study will be crucial in understanding the potential for ectotherms to adapt in the Anthropocene.

EFFECTS OF FASTING AND REFEEDING ON GROWTH PERFORMANCE AND ENERGY UTILIZATION OF JUVENILE ASIAN SEA BASS (LATES CALCARIFER)

Thuy T.N. Le (University of Turku, Finland), Tsung-Han Lee (National Chung Hsing University, Taiwan)

thuy.le@utu.fi

This study focused on how different fasting and refeeding regimes affected growth performance, energy utilization, and mRNA expression of appetite-regulatory hormones (ghrelin and leptin) and growth-regulatory hormones (insulin-like growth factor-1;igf-1) of Asian sea bass. 120 fish were selected at random for 4 experimental groups (30 fish in each group). Each group consisted of two FRP tanks with fresh water. The fish in the control-group tanks were fed daily throughout the experiment, whereas the fish in the treatmentgroup tanks were fasted for 4, 8, 14, and 21 days (group 1, 2, 3, and 4, respectively), followed by 14 days of refeeding. Reduced growth performance was found to be associated with longer periods of fasting. After 14 days of refeeding, however, the treated fish in the group 4 exhibited compensatory growth. Following fasting, the hepatosomatic index was considerably lower than that of the control fish in all groups. Ghrelin expression in stomachs increased significantly after 4 days of fasting, then returned to normal after refeeding. Leptin expression in livers exhibited similar patterns for groups 3 and 4, which were increased in treated fish during fasting periods. Igf-1 expression in livers was significantly higher in fasted individuals after 4 days of fasting, but decreased after 8 and 21 days of fasting in the treatment groups. To summarize, refeeding after fasting may result in a compensatory growth response in L. calcarifer. Nevertheless, starvation can alter the liver histology, and the length of fasting and refeeding periods influences the recovery capability.

A13.116 FUNCTIONAL ASSESSMENT OF PUTATIVE CHEMO CO-RECEPTORS IR25A AND IR93A OF PREDATOR PERCEPTION IN DAPHNIA

Wednesday 5 July 2023

POSTER SESSION

Joshua Huster (Ruhr-University Bochum, Germany), Annette Graeve (Ruhr-University Bochum, Germany),

Alina Keilmann (Ruhr-University Bochum, Germany),

Deria M Görl (Ruhr-University Bochum, Germany),

Julia Mayweg (Ruhr-University Bochum, Germany),

Ronja Fiedler (Ruhr-University Bochum, Germany),

Jana Plaßmann (Ruhr-University Bochum, Germany)

Petra Wahle (Ruhr-University Bochum, Germany),

Linda C Weiss (Ruhr-University Bochum, Germany)

joshua.huster@rub.de

The freshwater crustacean Daphnia is well known to adapt to an increased predation risk, through the expression of predator specific inducible defences. Some of these defensive strategies can be seen in form of morphological adaptations, like the formation of spines, thorns or neckteeth, increasing the individual’s fitness. The expression of these inducible defences are initiated by predator specific chemical cues. However, the mechanisms of chemoreception in Daphnia have only been studied to a limited extent and especially the involved chemoreceptors remain unknown. Ionotropic receptors (IRs) are discussed as a central element of chemoreception in crustaceans. In silico, two putative co-receptors have been suggested, i.e. IR25a and IR93a, that together with dedicated tuning receptors form a functional chemoreceptor. We here tested the involvement of IR25a and IR93a in predator perception in three Daphnia species

A13.115

(D. magna, D. longicephala and D. lumholtzi) responding to three different predator cues (Triops, Notonecta, and Gasterosteus). With the help of RNAinterference (RNAi) we knocked down IR25a and IR93a. Knock-down animals did not express defensive features indicating that the animals lose their sense of smell. We confirmed knock-down of the target gene using quantitative PCR and reduced protein abundancy with immunofluorescence. This study provides a first functional proof of both chemo co-receptors being involved in predator perception and probably chemo perception per se.

A13.117 ENVIRONMENTAL PHYSIOLOGY OF TORPOR IN THE EUROPEAN SANDHOPPERTALITRUS SALTATOR.

Wednesday 5 July 2023 POSTER SESSION

John I. Spicer (University of Plymouth, United Kingdom), Jack Bush (University of Plymouth, United Kingdom), Ellen Tully (University of Plymouth, United Kingdom), Ethan Cooke (University of Plymouth, United Kingdom)

j.i.spicer@plymouth.ac.uk

Extracellular magnesium concentration ([Mg2+ ]h ) increases disproportionately to other extracellular ions at low environmental temperatures in, the European sandhopper Talitrus saltator. torpor, historically reported as winter ‘hibernation’ over the past 150 years. Is also associated with low temperature and high [Mg2+ ]h . Here we present experimental evidence, from in situ and laboratory studies that while there is a predictable increase in [Mg2+ ]h with decreasing temperature, the [Mg2+ ]h of torpid individuals is greater than that of active individuals at equivalent low temperatures (<4°C). This implicates Mg2+ in the ‘hibernation’ of T. saltator, as does the fact that experimentally blocking the antennal gland (which concentrates urine [Mg2+ ]) results in sandhoppers becoming torpid even at high temperatures (15°C). Furthermore in the laboratory sandhoppers acclimated (5 days) to T = 20°C and then transferred acutely to T = 2 or 6°C showed a significantly greater increase in both [Mg2+ ]h and the frequency of torpor than individuals acclimated to T = 10°C. From this we suggest that high temperature acclimation will modify sandhopper torpor by increasing the low temperature threshold for [Mg2+ ] accumulating in the hemolymph. If this generalises large sandhoppers will still hibernate in warmer winters, where wrack decomposition will be dependent on how temperature affects feeding rate of non-hibernating individuals. This study illustrates the importance of understanding physiological mechanisms when making predictions about marine life in a warming world.

gwangseok.yoon@utoronto.ca

Elevated CO2 could either decrease or increase activity in marine fish. Although it is hypothesized to be a result of reduced sensitivity of olfactory neurons or neurotransmitter function, other physiological parameters such as muscle physiology and aerobic metabolism could also play a role in the altered activity. In this study, we examined the physiological mechanism that drives changes in activity of threespine sticklebacks under elevated CO2. Marine threespine sticklebacks were captured from Bamfield inlet, and exposed to current (~750 μatm; pH 8.0, the current level), medium (~1,500 μatm; pH 7.7, costal upwelling events) and high (~3,000 μatm; pH 7.1, predicted future levels) CO2 for two weeks. Sampling was performed at one and two weeks of exposure to assess baseline activity, group behaviour, escape response, muscle cellularity and metabolic rate. The total distance moved and average speed were higher in medium group than low at both time points (p<0.05), but not different from the high group. Inter-individual distance was higher in the medium level at one week of exposure than those exposed to the current level (p<0.05), but not different from the high level. Conversely, maximum escape speed was lower in the medium level than the current level at one week exposure (p<0.05). Metabolic rate was lower in the high level than the current level at both time points albeit statistically insignificant. Effects of CO2 on muscle physiology and aerobic metabolism will be discussed in the context of behavioural responses to elevated CO2 in marine sticklebacks.

A13.119 THE DIGESTIVE SYSTEM OF A CRICKET PULVERIZES POLYETHYLENE MICROPLASTIC BEADS

Thursday 6 July 2023 09:00

Marshall W Ritchie (Carleton University, Canada), Jennifer F Provencher (Environment and Climate Change Canada, Canada), Jane E Allison (Carleton University, Canada), Matthew J Muzzatti (Carleton University, Canada), Heath A MacMillan (Carleton University, Canada)

marshallritchie@cmail.carleton.ca

A13.118

UNDERSTANDING HOW ELEVATED CO2 INFLUENCES THE ACTIVITY AND METABOLISM OF A COSTAL MARINE FISH

Wednesday 5 July 2023 POSTER SESSION

Gwangseok R Yoon (University of Toronto Scarborough, Canada), Liam R Tigert (University of Toronto Scarborough, Canada), Elissa Khodikian (University of Toronto Scarborough, Canada), Cosima Porteus (University of Toronto Scarborough, Canada)

Microplastics (MPs; plastics smaller than 5 mm in size) are a growing environmental concern but a poorly understood threat to biota. The potential interactions terrestrial organisms (e.g., insects) have with MPs have been understudied, especially with an estimated 4900 megatons of plastics to date being directed to terrestrial systems and some plastic specifically added to the soil in agricultural systems. We used a generalist insect (a cricket; Gryllodes sigillatus) to examine whether individuals would ingest and transform MPs in their food to explore the fate of the MPs. We fed crickets fluorescent MPs mixed into a standard diet (0, 2.5, 5, and 10% w/w) and dissected the major gut regions to isolate the MPs within. By comparing plastic content and fragment size within regions of the gut, we sought to identify whether and where crickets can fragment ingested MP particles. Given the digestive tract morphology of this species, we expected that the crickets would both ingest and egest the MPs. We also predicted that the MPs would be fragmented into smaller pieces during this digestive process. We found that G. sigillatus can indeed ingest MPs, and we found that when fed 100 µm MPs, individuals egested much smaller pieces (equal to or smaller than 2 µm). The bulk of this fragmentation of the MP occurs early in the digestive process of this insect (e.g. during mastication). These findings suggest that generalist insects can serve as agents of plastic transformation in their environment when they encounter MPs.

A13.120 CHARACTERIZATION OF DIGESTIVE PROTEASES IN THE SEA URCHIN LARVA UNDERLINE A CONSERVED FUNCTION IN THE DEUTEROSTOME GUT

Thursday 6 July 2023 09:00

Jasper Hildebrand (Christian-Albrechts-University, Germany), Marian Hu (Christian-Albrechts-University, Germany), Meike Stumpp (Christian-Albrechts-University, Germany)

jhildebrand@zoologie.uni-kiel.de

Digestive systems are complex organs that allow organisms to absorb energy from their environment to fuel vital processes like growth, development and the maintenance of homeostasis. A comprehensive understanding of digestive physiology is therefore essential to fully understand the energetics of an organism. The digestion of proteins is of particular importance because most heterotrophic organisms are not able to synthesize all essential amino acids. While Echinoderms are basal deuterostomes that share a large genetic similarity with vertebrates their digestion physiology remains largely unexplored. Using a genetic approach, our work demonstrated that several protease genes including an enteropeptidase, aminopeptidase, carboxypeptidase and trypsin involved in mammalian digestive networks are also found in sea urchin larvae. Through characterization including perturbation experiments with different food treatments and pharmacological inhibition of proteases using specific inhibitors, as well as transcriptomic analysis we conclude that the trypsin-2 gene codes for a crucial enzyme for the protein digestion in Strongylocentrotus purpuratus. Measurements of in vivo digestion rates in the transparent sea urchin larva were not altered by pharmacological inhibition of trypsin (Soybean Trypsin Inhibitor) or serine proteases (Aprotinin) suggesting that proteases are not critically involved in the initial step of microalgal breakdown. Our work provides new insights into the digestive physiology of a basal deuterostome and allows comparisons from the molecular to the functional level in the digestive systems of vertebrates and mammals. This knowledge will contribute to a better understanding for conserved digestive mechanisms that evolved in close interaction with their biotic and abiotic environment.

A13.121 EVALUATING THE IMPACT OF ACIDIFICATION ON THE DIGESTIVE AND METABOLIC FUNCTIONING OF PELAGIC SQUID

Thursday 6 July 2023 09:30

Yung-Che TSENG (Academia Sinica, Taiwan), Pao-Long Kuan (Academia Sinica, Taiwan)

yctseng@gate.sinica.edu.tw

The effects of ocean acidification on the metabolic rates of marine organisms have been thoroughly studied and documented. This study attempted to determine how CO2-induced acidification affected the digestive and metabolic processes of the pelagic squid species Sepioteuthis lessoniana. During the course of three months, juvenile squids were kept in both regular seawater (control group, pH 8.1) and CO2-acidified seawater (acidified group, pH 7.8). The weight, mantle length, and digestive-somatic index (DSI) of the acidified group were

significantly lower than those of the control group, showing that CO2induced acidification may affect the morphology of the squid digestive glands. However, our further activity assay also demonstrated that seawater acidification increased the activity of digestive enzymes such as amylase, trypsin, and lipase in the squid's digestive glands. This indicates that pelagic squid may be able to adapt to acidified conditions by increasing the activity of metabolic enzymes in their smaller digestive glands, enabling them to sustain energy demands and acid-base homeostasis under acidification stress.

A13.122 EATING WITH YOUR MOUTH CLOSED: SPECIALIZED CELLS AND TRANSPORTERS ABSORB ENVIRONMENTAL PEPTIDES IN TELEOST LARVAE.

Thursday 6 July 2023 09:45

Avner Cnaani (Agricultural Research Organization, Israel), Pazit Con (Agricultural Research Organization, Israel) avnerc@agri.gov.il

Nutrient absorption through the skin and gills into the organisms’ tissues has been documented in several aquatic invertebrates from different phyla and even in the Pacific hagfish. However, the actual absorption mechanism is still unknown. In teleost fish, as in all jawed vertebrates, intestinal absorption is considered as the sole source of nutrients.

The proton-dependent peptide transporters (PepT) of the slc15a gene family are the only known mechanism for cellular absorption of di- and tri-peptides within the animal kingdom. In this study, we explored the expression and localization of PepT2 in Mozambique tilapia (Oreochromis mossambicus) larvae. Transcript levels of PepT2 in dissected yolk-sacs from larvae showed significant expression during the larval developmental period. Immunofluorescence staining of PepT2 and Na/K-ATPase (NKA) on whole larvae revealed co-staining within ionocytes on the yolk-sac membrane. While NKA staining was observed on the ionocytes' basolateral membrane, PepT2 staining was restricted to the apical pit of the ionocytes, facing the surrounding water.

While previous works have described amino acid absorption in crustaceans and agnathans, the cellular mechanisms of environmental nutrient absorption have remained obscure. In this study, we identified a nutrient transporter located on integument-specific cells, facing the outside aquatic environment, in a teleost larvae. This is the first indication of such absorption in teleosts, and the first evidence of a possible absorption mechanism through PepT2, which is localized in the apical pit of yolk-sac ionocytes.

DOGFISH (SQUALUS SUCKLEYI)

Thursday 6 July 2023 10:00

A13.123 COMPARING GLUCOSE ACQUISITION STRATEGIES BETWEEN TWO ANCIENT FISH SPECIES: LAKE STURGEON (ACIPENSER FULVESCENS) AND PACIFIC SPINY

Here we address knowledge gaps regarding the evolution of glucose acquisition in vertebrates by examining glucose uptake in the gastrointestinal tract (GIT) of ancient fish, including lake sturgeon (Acipenser fulvescens) and Pacific spiny dogfish (Squalus suckleyi). Within the GIT of these “living fossils” evolved an organ called the spiral valve. Due to its scroll-like internal folds, the spiral valve presumably increases gastrointestinal surface area and slows down chyme passage to maximize nutrient absorption, suggesting it to be primarily responsible for nutrient acquisition. However, there is currently minimal functional data to support this claim. This study aims to determine the functional role of the spiral valve in carbohydrate breakdown and glucose acquisition during different feeding states and determine if this role changes in organisms with different life histories. To test this, we assessed glucose digestibility and transport capacity along the GIT of A. fulvescens and S. suckleyi in fed and fasted fish. Digestibility was assessed through biochemical assays for the carbohydrate digesting enzyme maltase, while transport capacity was determined via i) mRNA abundance of the primary dietary glucose transporter (SGLT1), and ii) through in vitro intestinal fluxes. In comparison to A. fulvescens, the spiral valve in S. suckleyi has an elevated role in glucose digestion and transport. There were no significant postprandial changes in SGLT1 mRNA abundance nor maltase activity in A. fulvescens in comparison to S. suckleyi, supporting their feeding strategies with A. fulvescens being continuous feeders and S. suckleyi being opportunistic feeders.

A13.124 HIGH CARBOHYDRATE DIET DIFFERENTLY AFFECTS HEPATIC DNA METHYLATION IN TROUT DEPENDING ON STAGE OF LIFE, SEX, AND DURATION OF NUTRITION

Thursday 6 July 2023 10:15

Lucie Marandel (INRAE, France), Cécile Heraud (INRAE, France), Thérèse Callet (Thcallet@gmail.com, France)

lucie.marandel@inrae.fr

In order to increase the sustainability of trout aquaculture, fish meal and oil, must be replaced by alternative terrestrial plant products among which digestible carbohydrates (CHO) are good candidates. However, juvenile trout is a poor user of CHO displaying a persistent post-prandial hyperglycaemia and a decrease in growth that is not the case for broodstock. In addition, we recently showed that CHO could act as epigenetic modulators in juveniles, by-inducing a global hepatic DNA hypomethylation, at short term direct nutrition. Nevertheless, these results were only obtained at the juvenile stage and in females. Epigenetics answer to environmental changes can however be dependent on the sex and life stage leading to divergent metabolic and zootechnical phenotypes. We thus addressed the question of the DNA methylation modifications induced by direct nutrition with CHO in short (few meals) and long (several months) –term at key life stages (juveniles, broodstock), but also by indirect nutrition by CHO in offspring from broodstock fed a whole reproductive cycle. We

also took into account different sex: males, females and neomales. This exploration was performed using UV-LC allowing to monitor all C5-cytosine variants (5-mC, 5-hmC, 5-caC, 5-fC, C) in the context of CpG and non-CpG. CHO nutrition induced a modification of 5-mC levels mostly in neomales and preferentially at early stages of life. Of huge interest, this epigenetic phenotype was found in all-sex alevins born from broodstock fed during a whole reproductive period with a high CHO diet suggesting an intergenerational transmission of the phenotype.

A13.125 INVESTIGATION OF AQP9 AND ITS ROLE IN CALCIFYING CELLS OF THE SEA URCHIN LARVA

Thursday 6 July 2023 11:00

Ann-Sophie Matt (Institut of Physiology CAU Kiel, Germany), Marian Y. Hu (Institut of Physiology CAU Kiel, Germany)

a.matt@physiologie.uni-kiel.de

Aquaporins (AQP) are ubiquitous membrane proteins found across all domains of life and are best known for their function in conducting water, small polar solutes and gases across biological membranes. Single cell transcriptomic analyses and in situ hybridization identified an AQP9 homologue in the calcifying primary mesenchyme cells (PMCs) of the sea urchin larva with the underlying cellular function in the calcification process being unknown.

Heterologous expression of sea urchin suAQP9 in Xenopusoocytes revealed its function as a H2 O channel and Phloretin, an AQP9 inhibitor effectively suppressed water permeability by suAQP9 in a dose dependent manner. In the sea urchin larva, inhibition of suAQP9 by Phloretin resulted in decreased calcification rates underlining a contribution of suAQP9 to the calcification process.

Determination of swelling rates by live cell imaging of PMCs in combination with cytosolic Calcein-AM quenching revealed altered water flux in PMCs in the presence of 100 µM phloretin compared to DMSO controls.

Whole mount in situ hybridization (WHISH) results confirmed expression of AQP9 restricted to PMCs and immunostainings using a sea urchin-specific antibody demonstrate localization of AQP9 in vesicles facing the calcification front. More experiments, including vesicular water flux measurements will be performed to reveal the function of AQP9 in these vesicles.

We propose an important contribution of AQP9 in the calcification process of the sea urchin larva by potentially mediating water flux in intracellular compartments supporting CaCO3 precipitation. This knowledge provides novel insights into the role of water channel activity in the calcification process of marine organisms.

Thursday 6 July 2023 11:00

A13.126 PATTERNS OF CARBONIC ANHYDRASE LOCALISATION IN DERIVED, BASAL, AND DEVELOPING FISHES

Jenna M. Drummond (University of Manitoba, Canada), Alyssa M. Weinrauch (Univeristy of Manitoba, Canada), W. Gary Anderson (Univeristy of Manitoba, Canada)

drummon4@myumanitoba.ca

Standen (University of Ottawa, Canada), Peter Allen (Mississippi State University, United States), Colin J Brauner (UBC, Canada)

cnelson@zoology.ubc.ca

Teleosts comprise half of all vertebrates and have successfully invaded every aquatic habitat on Earth. They owe this success, at least in part, to their unique oxygenation system. This system is comprised of highly pH sensitive hemoglobins (Hb; large Bohr/Root effects), red blood cell (RBC) intracellular pH (pHi) protection, and a heterogeneous distribution of plasma accessible carbonic anhydrase (paCA; absent at the gills). Together these components enhance oxygen (O2) unloading at the tissues while protecting O2 uptake at the gills during a generalised acidosis. While the first two components have received much research interest, the third component, a heterogeneous distribution of paCA has not. It is hypothesised that the absence of paCA in teleostean gills is due to the presence of the large Root effect and the associated risks to O2 loading. We confirm the lack of paCA in all four gill arches of rainbow trout, which until now had been assumed based on data from gill arch 2. We also investigated various CA characteristics in developing rainbow trout and in basal actinopterygians to utilise natural scenarios where Hb pH sensitivity (Bohr/Root effect magnitude) is reduced. We show that the respiratory system of pre-hatch rainbow trout is more similar to elasmobranchs than their adult counterparts, and that branchial paCA was likely lost much earlier in teleostean evolution than previously thought.

A13.127 CHALLENGES ASSOCIATED WITH TIDAL VENTILATION IN DRAGONFLY NYMPHS

Thursday 6 July 2023 11:30

Daniel J. Lee (University of British Columbia, Canada), Philip G.D. Matthews (University of British Columbia, Canada)

danlee@zoology.ubc.ca

Dragonfly nymphs are unusual among water-breathing animals as they breathe by tidally ventilating a blind-ending rectal gill. Tidal ventilation of an aquatic gas exchange organ is expected to dramatically reduce its oxygen (O2) extraction efficiency (OEE) relative to unidirectional ventilation due to the mixing between fresh inhaled water and stale residual water within the gill, combined with the challenges of accelerating and decelerating a dense, viscous fluid. This study aimed to quantify the tidal volume, ventilation frequency, and OEE of the dragonfly nymphs' rectal gill during progressive hypoxia to determine how it compares with other water-breathing strategies. A custom-designed apparatus measured the nymphs' minute ventilation and metabolic rate during progressive hypoxia, and the OEE was calculated. Increasing hypoxia was associated with a significant increase in minute ventilation that was attributed solely to increases in breathing frequency while tidal volume remained constant. There were no significant decreases in the nymphs' metabolic rate during hypoxia, and as a result the water-convection requirement increased significantly as the water became hypoxic. The calculated OEE of nymphs in normoxia (40%) was substantially lower than values from unidirectional water-breathers (60 - 83%). However, nymphs were able to maintain their OEE even during severe hypoxia, whereas other animals show substantial reductions in their O2 extraction. Thus, these data suggest that while the O2 extraction efficiency of dragonfly nymphs

in normoxia is low as predicted from theory, it appears more resistant to hypoxia than in other water-breathing animals.

A13.128 PRODUCING A LARGER SMOLT: DOES PHOTOPERIOD MANIPULATION IMPROVE PHYSIOLOGICAL PERFORMANCE ACROSS SEAWATER TRANSFER IN THREE SIZES OF ATLANTIC SALMON?

Thursday 6 July 2023 11:45

Daniel Montgomery (University of British Columbia, Canada), Le Thi Hong Gam (University of British Columbia, Canada), Yangfan Zhang (Harvard University, United States), Rachael Mackinnon (University of British Columbia, Canada), Daniel Laronde (University of British Columbia, Canada), Colin J Brauner (University of British Columbia, Canada), Jeffrey G Richards (University of British Columbia, Canada)

danmont@zoology.ubc.ca

A goal of salmon aquaculture is to produce larger, physiologically robust smolts to reduce the time spent in marine net pens prior to harvest. However, little is known about whether standard processes to induce smoltification provide benefits in the production of large smolts. In Atlantic salmon reared under continuous light (24L:0D) we applied an artificial photoperiod manipulation (8 weeks of 12L:12D followed by 4 weeks of 24L:0D before seawater transfer) at three sizes to produce fish of ~200g, ~500g, and ~1200g at seawater transfer. Performance of these presumptive large smolts was compared to fish maintained in constant light until seawater transfer. Photoperiod manipulation resulted in a significant increase in gill Na+ -K+ ATPase activity 24 hours after seawater transfer in ~500g and ~1200g fish but this did not translate to differences in plasma ion levels or osmolality. Photoperiod manipulation increased growth rate of ~500g fish during the first two months following seawater transfer by 0.32 % body mass/day but had no significant effect for ~200 or ~1200g fish. Photoperiod manipulated salmon had ~13 % increased basal energetic costs (ṀO2min ) in all size groups but photoperiod manipulation did not alter the effect of seawater transfer on metabolic rate of salmon. Lastly, photoperiod manipulation decreased hypoxia tolerance of ~500g and ~1200g fish at the time of seawater transfer. Overall, our results suggest standard photoperiod manipulations can successfully improve growth after seawater transfer of ~500g salmon but may cause trade-offs which increase base energetic costs and reduce hypoxia tolerance.

A13.129 MENOPAUSE,

AND THE EXPENSIVE BRAIN

Thursday 6 July 2023 12:00

Pat Monaghan (Professor, United Kingdom), Edward Ivimey-Cook (University of Glasgow, United Kingdom)

Pat.Monaghan@glasgow.ac.uk

In some species, a permanent curtailment of reproduction part way through the lifespan of adult females is a feature of their evolved life history. So far as we know, the existence of such a post reproductive

MITOCHONDRIA

Charlotte Nelson (University of British Columbia, Canada), Angelina M Dichiera (UBC, Canada), Ellen H Jung (UBC, Canada), Emily

life stage is rare; so far reasonably robust evidence for its occurrence is confined to only a very small number of species. That it occurs at all appears to contradict our view of natural selection operating to maximise fitness and special circumstances must exist to explain its occurrence.. We present a new hypothesis which posits that the duration of female fertility in certain long-lived, highly encephalised species with no post-natal oogenesis is limited by the need for intense screening of oocyte mitochondria to support endothermy coupled with the high energy requirement for the development and maintenance of the large brain size required for their complex social living. This limits the number and shelf-life of oocytes, creating an antagonistically pleotropic effect with the later life cost being female infertility. But the end of the fertile period is no time to die. The opportunity for multiple inclusive fitness benefits arising from protracted parental care of offspring, overlapping generations and kin group structures means that continued survival of post reproductive females is favoured by selection.

A13.130 A BEATING HEART - CARDIAC PERFORMANCE AND CARDIOMYOCYTE METABOLISM

OF THE EUROPEAN OYSTER, OSTREA EDULIS

Thursday 6 July 2023 12:15

Sandra Götze (Alfred-Wegener Institute, Germany), Carl Reddin (Leibniz Institute for Research on Evolution and Biodiversity, Germany), Christian Bock (Alfred-Wegener Institute for Marine and Polar Research, Germany), HansOtto Pörtner (Alfred-Wegener Institute for Marine and Polar Research, Germany)

sandra.goetze@awi.de

Global warming and the increasing frequency of heat waves are a rising threat to marine species. We examined cardiac function and metabolism in European oysters (Ostrea edulis) in response to warming. Starting at 22°C, oysters were exposed to either acute or gradual warming (+2°C/h or 2°C/24h) until all oysters died. We modeled cardiac output curves and derived corresponding cardiac indices. Heart samples were collected at different temperatures and analyzed by 1 H NMR spectroscopy. Under acute warming (2°C/h) cardiac activity was maximal at 30 °C and steadily decreased with further waming (ABT = 30.5 °C). With decreasing cardiac performance oysters switched to anaerobic metabolism. At 36 °C and 37 °C, severe fluctuations in Krebs-cycle-related metabolites occurred, indicating profound energetic imbalances. Except for this, only minor metabolic changes were observed. Oysters died at a maximum of 39 °C (LT50 = 36.9 ± 0.5 °C). In contrast, cardiac activity of oysters exposed to gradual warming (2°C/24 h) decreased sharply beyond 33.9 °C (ABT) and ceased completely within the first 12 hours at 36°C (LT50 = 34.8 ± 0.2 °C). At high temperatures, more metabolic pathways were affected comprising mainly changes in amino acid, lipid and carbohydrate metabolism, however, adjustments were more subtle compared to acute warming. The rate of warming has differential impacts on cardiomyocyte performance and metabolic responses which may relate to the rate-dependent shifts in thermal tolerance. Our results highlights the importance of integrating metabolism to organismic performance to better understand the dynamic impacts of heat waves for marine ectotherms.

A13.131 EX VIVO CARDIAC PERFORMANCE OF UN-TRAINED AND TRAINED RAINBOW TROUT (ONCORHYNCHUS MYKISS) DURING ACUTE HYPOXIA

Thursday 6 July 2023 14:30

Katja Anttila (University of Turku, Finland), Anna Papadopoulou (University of Turku, Finland), Eila Seppänen (Natural Resources Institute, Finland), Giovanna Mottola (University of Turku, Finland), Tomi Streng (University of Turku, Finland)

katant@utu.fi

Aquaculture is one of the fastest growing food production industries. However, it is facing challenges with climate change causing reduced water oxygen levels and warming in fish hatcheries. These environmental stressors are also causing fish die-offs. There is, thus, an urgent need to address the challenges. One physiological reason leading to mortalities could be a failure in fish’s cardiovascular performance. The aquaculture fish are especially concerned since current rearing practices, with unlimited food and no need to swim, have caused impairments in their cardiovascular system. One way to enhance the cardiovascular performance of fish in aquaculture could be exercise training. The objective of the current study was to reveal if exercise training could enhance the hypoxia tolerance of the heart. The fish were divided into two groups: control fish swimming in regular aquaculture tanks with regular water flow velocity of 0.5 body lengths/s and training fish swimming six hours per day with velocity of 1.3 body lengths/s. The rest of the day and weekends the velocity was the same as in the control group. The training lasted five weeks. After the training, the hearts of the fish were removed and measured in the working-heart Langendorff-system where the hearts were continuously perfused with saline solution. The oxygen level of the saline was progressively reduced to reveal if there were differences in the intrinsic heart rate and pressure production capacities between the groups in different oxygen levels. The results will reveal if training can enhance the hypoxic heart performance of aquaculture fish.

A13.132 LONG-TERM SUSTAINED SWIMMING IMPROVES SWIMMING PERFORMANCE IN CHINOOK SALMON, ONCORHYNCHUS TSHAWYTSCHA WITH AND WITHOUT SPINAL SCOLIOSIS

Thursday 6 July 2023 14:30

Leteisha A Prescott (University of Tasmania, Australia), Jane E Symonds (Cawthron Institute, New Zealand), Seumas P Walker (Cawthron Institute, New Zealand), Matthew R Miller (Cawthron Institute, New Zealand), Jayson M Semmens (University of Tasmania, Australia), Chris G Carter (University of Tasmania, Australia)

leteisha.prescott@utas.edu.au

Exercise training during early production is becoming a key component in salmon hatcheries as exercise enhances several production-related traits in salmonids. Exercise conditions for rearing salmonids are continually being optimised and now that the salmonid industry is

developing offshore, training is being considered as a tool to prepare stocks for high energy environments. It is unknown if exercise can enhance traits in other understudied salmonid species and in individuals with spinal curvature, which is a common issue within some salmon farms. Here we exposed Chinook salmon to low (0.3 bl s-1) and moderate (0.8 bl s-1) tank velocities for ten to eleven months and quantified respiratory and swimming performance in individuals with and without mild scoliosis. Further, we investigated compositional and morphological responses at cellular and whole-body levels. Raising Chinook salmon under moderate velocities improved swimming performance in individuals with and without spinal curvature, but recovery processes in individuals with spinal curvature were greater. Fat content was reduced in fish raised under moderate velocities, while protein content was higher in individuals with spinal curvature. Together, the results of this study shows benefits for integrating exercise training into hatchery settings (i.e., pre- and post-smolts) to prepare stocks for offshore farming and provides evidence that some exercise-enhanced traits can be translated into individuals with spinal curvature, but concerns remain for individuals with more severe cases. Additionally, this study reveals that the product quality of fish farmed may change in offshore locations, and that optimising nutrient profiles for offshore feeds should be considered.

A13.133 SWIMMING PERFORMANCE AND POST-EXERCISE RECOVERY IN MAHI-MAHI, A HIGH-PERFORMANCE PELAGIC TELEOST - METHODS MATTER. 1. RESPIROMETRY AND TISSUE METABOLITES

Thursday 6 July 2023 15:00

Rachael M. Heuer (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Chris M. Wood (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), John D. Stieglitz (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), LeeAnn Frank (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Daniel Benetti (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Martin Grosell (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States)

rheuer@miami.edu

Energetic demand associated with exhaustive exercise is examined using one of two methods. Using swim tunnel respirometry, oxygen consumption (ṀO2) is measured as water velocity is increased stepwise until the animal fails. In the second method, the animal is chased until exhaustion and then placed in a respirometer for measurements of ṀO2. The objective of this study was to compare these methods and examine recovery excess post-exercise oxygen consumption (EPOC) in the highly migratory athletic pelagic fish, mahi-mahi (Coryphaena hippurus). Mahi were randomly assigned to one of 5 groups: control, swim tunnel respirometry “Ucrit ,” chase (20 min) to exhaustion, 4 hours post-Ucrit , 4 hours post-chase, and 7 hours post-chase. To gain insight into fuel usage associated with these observations, we also measured white muscle, red muscle, and liver lactate and glycogen. Swim tunnel respirometry led to a significantly higher maximum metabolic rate and aerobic scope compared to chase to exhaustion. White muscle lactate did not differ between Ucrit and chase groups. Red muscle

lactate showed a >2-fold increase in mahi immediately following Ucrit and remained elevated 4 hours post recovery, while the chase group showed only a slight increase from controls (1.3-fold). Liver lactate was low but showed a 3.8-fold increase in chased mahi with little differences seen in other treatment groups. Glycogen and intracellular pHi in tissues and quantification of EPOC will also be presented. Overall, these data suggest that Ucrit and chase methodologies elicit different results and could make comparisons difficult across studies (GoMRI-SA-1520, NSERC-Discovery).

A13.134 SWIMMING PERFORMANCE AND POST-EXERCISE RECOVERY IN MAHI-MAHI, A HIGH-PERFORMANCE PELAGIC TELEOST - METHODS MATTER. 2. INTERNAL PHYSIOLOGICAL DISTURBANCES.

Thursday 6 July 2023 15:15

Chris M. Wood (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Rachael M. Heuer (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), John D. Stieglitz (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), LeeAnn Frank (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Daniel Benetti (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States), Martin Grosell (University of Miami Rosenstiel School of Marine Atmospheric and Earth Science, United States)

woodcm@zoology.ubc.ca

Internal physiological disturbances were evaluated in mahi-mahi (Coryphaena hippurus) rapidly euthanized at various points in the Ucrit versus chase exercise and recovery regimes of the preceding presentation. Immediately after 20-min chase to exhaustion, plasma lactate levels were elevated approximately 8-fold, but the increase was only 2-fold in fish sampled at the point of exhaustion in the Ucrit test. Elevations in plasma cortisol (4-fold), ammonia (1.5-fold), and osmolality (1.15-fold), red blood cell swelling, and reversal of the red blood cell (RBC) pHe-pHi gradient due to marked elevation of pHi were comparable in the two treatments. Increases in plasma glucose and splenic discharge of RBCs tended to be greater in the Ucrit treatment. In both treatments, most parameters were restored to control levels by 4 h despite different patterns of oxygen consumption (MO2) elevation and recovery. However, elevation of the RBC pHi gradient persisted through 7h recovery in the chase treatment. These findings will be discussed in relation to simultaneous measurements of tissue metabolites and MO2 in the same fish. Overall, our data indicate that chase and swim performance methodologies to induce exhaustive exercise yield different results and may confound comparisons across studies. Generally, our data suggest a greater anaerobic contribution to exercise metabolism in the chase treatment, with broader implications for catch-and release angling. (GoMRI-SA-1520, NSERC-Discovery).

A13.135 THE TEMPERATURE-SIZE RULE IN FISHES: WHAT ROLES FOR OXYGEN SUPPLY AND DEMAND?

Thursday 6 July 2023 15:30

Timothy D Clark (Deakin University, Australia)

t.clark@deakin.edu.au

The temperature-size rule (TSR) in the phenomenon whereby ectotherms do not grow as large when in warm environments. This pattern is seen in lab-based experiments and also in natural environments undergoing anthropogenic warming. A mismatch in oxygen supply (from the environment) and demand (from organismal metabolism) is thought to play some role in driving TSR observations in aquatic ectotherms, but scientific opinions are divided and heated controversy remains. This presentation will cover what is known about the TSR in fishes and present findings from lab experiments where we have manipulated environmental parameters to determine how oxygen supply/demand might contribute to the TSR phenomenon.

A13.136 DEVELOPMENT OF AN IN SITU LIVER PERFUSION IN A SHARK SPECIES, SQUALUS SUCKLEYI, TO ANALYSE HEPATIC ENERGY BALANCE.

Thursday 6 July 2023 15:45

Alexandra N Schoen (University of Manitoba, Canada), Alyssa M Weinrauch (University of Manitoba, Canada), Ian A Bouyoucos (University of Manitoba, Canada), W Gary Anderson (University of Manitoba, Canada)

schoena@myumanitoba.ca

Metabolic processes in the liver are fundamental to whole-body energy balance in all vertebrates. Energy is mobilized from the liver, which can be dependent on the physiological condition of the organism (i.e. seasonality, feeding status, reproductive status, etc.). In elasmobranchs, several studies have used isolated hepatocytes to assess metabolite uptake and production. However, this is complicated in shark species as the high lipid content of the liver results in a very poor yield of isolated hepatocytes. Consequently, we developed an in situ liver perfusion for the first time in a shark species, the North Pacific spiny dogfish (Squalus suckleyi), that represents a physiologically relevant approach for determining changes in hepatic energy balance. Liver perfusions were prepared by cannulating the hepatic vein and the sinus venosus through the ventricle of the heart. Oxygen consumption was monitored over 3hrs (n = 11), which was consistently and significantly elevated above 0 ng O2 min-1kg wet tissue-1, confirming the viability of the perfusions over this time period. Furthermore, perfusion of the liver with homologous angiotensin resulted in a predictable decrease in outflow rate, showing that hemodynamic action of the perfusions remained intact. Removal and addition of both glucose and ß-hydroxybutarate (ß-HB) from the inflow was detected in the outflow, indicative of a change in use of these metabolites by the perfused liver. Lastly, outflow ß-HB concentrations were elevated above inflow ß-HB concentrations, highlighting endogenous hepatic ketogenesis (ß-HB production).

A13.137 “MCM10”: A NEW CANDIDATE GENE INVOLVED IN ZEBRAFISH HAEMATOPOIESIS

Thursday 6 July 2023 16:30

Serkan Dogan (McMaster University, Canada), Julien Bertrand (University of Geneva, Switzerland)

ssdserkan@hotmail.com

The primary roles of the blood tissue are to ensure the oxygenation of tissues and to provide the immunity of the organism. The main components of the blood tissue are renewed in the bone marrow of mammals which is ensured by haematopoietic stem cells (HSCs). The adult HSCs pool is derived from a subgroup of HSCs produced during the early developmental stage. Thus, it is important to understand the molecular mechanisms behind HSC emergence, expansion, and differentiation. In this study, we used the zebrafish model organism. Its high production capacity gives rise to optically transparent, easily manipulated embryos, making this model favourable to use in developmental biology. Remarkably, haematopoiesis is a conserved process through all vertebrates which helps us to translate our knowledge to clinical human studies. At the beginning of this study, I was focused on a gene, cndp2, formerly shown as a potential haematopoietic element in the cndp2 mutant line. However, the genetic&phenotypic screening and the loss of function assay showed that cndp2 is not involved in haematopoiesis. Further genetic and phenotypic screening of the mutant line helped us to determine a new candidate gene “mcm10”. In situ hybridization assay revealed its specific expression in the hemogenic endothelium. Moreover, the mcm10 mutants showed deficient definitive haematopoiesis. Taken together, we conclude that there is a specific requirement of mcm10 in the emergence of HSC. The fully uncovered mechanisms behind mcm10 induction would represent a keystone in the emergence of HSCs and also enlighten a non-conventional role of mcm10.

A13.138 ACUTE HYPOXIA SIGNIFICANTLY REDUCES ATLANTIC SALMON’S AEROBIC SCOPE AND DELAYED DIGESTION AT OPTIMUM AND HIGH TEMPERATURES.

Thursday 6 July 2023 16:30

Barbara Nuic Vidigal (The University of Queensland, Australia), Alyssa Bowden (The Univeristy of Queensland, Australia), Craig Franklin (The Univeristy of Queensland, Australia), Rebecca Cramp (The Univeristy of Queensland, Australia)

b.nuicvidigal@uq.edu.au

Warming oceans with combined low aquatic oxygen levels threaten Tasmanian Atlantic salmon (Salmo salar) aquaculture, pushing this species to its physiological limit. Increasing temperatures raise oxygen uptake rates (a proxy for metabolic rate), while hypoxia reduces oxygen availability. Thus, combining these stressors can reduce the oxygen available in the organism (aerobic scope, AS) for aerobic activities such as digestion, leading to poor growth. In addition, the energetic

cost of digesting, absorbing, and assimilating a meal (termed Specific Dynamic Action, SDA) can demand a high proportion of the AS and compete with other aerobic demands. Thus, it has been proposed that the observed reduced feed intake and growth under these challenging environmental conditions result from a protective mechanism to preserve the available AS. This research aimed to investigate the impact of environmental stress – chronic high temperature and acute hypoxia - on Atlantic salmon’s aerobic capacity and digestion. AS and SDA were measured at 15°C and 21°C at normoxia (above 75% air saturation) or exposed to hypoxia (~50% air saturation) for 1.5 h post-feeding. Impacts on gut transit were investigated by sampling pre- (~47h fasted) and post-feeding (at 2h, 7h, 30h). Atlantic salmon presented a reduced AS at 21°C and at hypoxia. Also, at the higher temperature, SDA peak increased and occupied a higher proportion of the AS. Moreover, gut transit from the stomach to the mid-intestine was temporarily delayed in hypoxia-exposed fish. Thus, both stressors affect Atlantic salmon energetics and digestion by reducing the AS and delaying gut transit. -45

A13.139 THE AIR-BREATHING FISH PANGASIANODON HYPOPHTHALMUS WITH HUGE GILLS VOIDS ALL

Thursday 6 July 2023 17:00

Magnus L Aaskov (Aarhus University, Denmark), Hans Malte (Aarhus University, Denmark), Mark Bayley (Aarhus University, Denmark)

magnus.aaskov@bio.au.dk

The facultative air-breathing fish Pangasianodon hypophthalmus native to the Mekong river system is a very active fish that migrates >2000km from the delta to breeding grounds in Cambodia. P. hypophthalmushas very large plastic gills whose respiratory surface area can vary from being on par with the most active water-breathers, to a small surface with almost no exposed lamellae. Its ability to air-breathe and its very high growth rate, even in deeply hypoxic water have contributed to its importance in aquaculture making it the most cultured air-breathing fish in the world. The typical gas-exchange pattern for air-breathing fish in hypoxia is to excrete CO2 to the water while obtaining O2 from the air. Consequently, it is believed that some O2 taken up by airbreathing is lost at the gills to the hypoxic water. To understand how P. hypophthalmus can both lose O2 and simultaneously maintain a very high growth rate in hypoxia, we quantified the extent of the O2 loss using a newly developed two-phase respirometer enabling the measurement of both O2 and CO2 gas-exchange in water and air. In severe hypoxia (31C°, PO2: ≈1.5mmHg) we found that P. hypophthalmus lost only 4.6% of aerial O2 uptake, while maintaining an aquatic CO2 excretion of 91%. Furthermore, at an aquatic PO2 of 4.7mmHg this loss was reduced to 3.4%. Previous oxygen profile and telemetry studies showed that P. hypophthalmus stays in surface waters when the PO2 is low, indicating that in the natural environment, P. hypophthalmus likely avoids all O2 loss.

A13.140 RELIABILITY OF THE ENTERPRISE POINT-OF-CARE (EPOC)

BLOOD ANALYZER’S CALCULATED ARTERIAL OXYGEN-HEMOGLOBIN SATURATION, IN IMMOBILIZED WHITE RHINOCEROS (CERATOTHERIUM SIMUM)

Thursday 6 July 2023 17:15

Thembeka K Mtetwa (University of Pretoria, South Africa), Leith CR Meyer (University of Pretoria, South Africa), Ashleigh C Donaldson (University of Pretoria, South Africa), Edward P Snelling (University of Pretoria, South Africa), Peter E Buss (South African National Parks, South Africa)

themburger@gmail.com

Blood analysis is used routinely in veterinary practice to assess cardio-respiratory and blood oxygenation status of white rhinoceros (Ceratotherium simum), but its reliability has never been determined. The study aimed to evaluate the reliability of calculated arterial oxygenhaemoglobin saturation (cSaO2) calculated by an Enterprise Point-ofCare (EPOC) blood gas analyzer by comparing these measurements with the arterial oxygen-haemoglobin saturation (SaO2) measured by a ‘reference method’ AVOXimeter 4000 co-oximeter in immobilized white rhinoceros. Eight white rhinoceros (Study 1) were immobilized with etorphine and given either butorphanol or an equivalent volume of saline intravenously after 30 minutes of immobilization. A further eight rhinoceros (Study 2) were immobilized with four treatments each (etorphine + injectable water, etorphine + azaperone, etorphine + midazolam, etorphine + medetomidine) with a two-week washout period in between immobilizations. To improve blood oxygen levels, animals were given butorphanol and provided with insufflated oxygen administered intranasally. Arterial blood samples were drawn, at designated time points, from aseptically prepared pinna of the ear and then analyzed using an EPOC blood analyzer and AVOXimeter 4000 co-oximeter. Bland-Altman [assessing bias, precision and limits of agreement (LOA)] and area root mean squares (ARMS) methods were used to determine the reliability of the EPOC’s cSaO2 when compared with simultaneously taken AVOXimeter co-oximeter’s SaO2 measurements. When compared with SaO2, cSaO2 measurements were unreliable, across the entire SaO2 range (bias =-4, precision =7, LOA=9to-18, and ARMS=8), because the EPOC blood analyzer calculates arterial oxygen-haemoglobin saturation based on human-specific conversion equation that is not always transferrable across species.

A13.141 RESPIRATORY GAS EXCHANGE MODIFICATIONS ARE LINKED WITH VARIATION IN EXERCISE FUELING IN SCORPIONS

Thursday 6 July 2023 17:30

Eran Gefen (University of Haifa- Oranim, Israel)

gefene@research.haifa.ac.il

Aerobic capacities in arachnids are typically correlated with considerable structural variation in their respiratory systems. An extensive tracheal system supports high rates of gas exchange in solifuges. Spiders possess book lungs, tracheae or both, and higher aerobic capacities

CO2 TO SURROUNDING HYPOXIC WATER WITH MINIMAL BRANCHIAL O2 LOSS

are observed in species in which book lung gas exchange is supported by well-developed tracheae. Scorpions vary greatly in their locomotor activity patterns. Non-burrowing Buthidae species largely express short bursts of activity, whereas Scorpionidae species dig burrows up to 1 m deep within hours, suggesting aerobically-fueled locomotion. Importantly, all scorpions are non-tracheated and possess four pairs of book lungs. We hypothesized that locomotion in surface-dwellers is largely fueled anaerobically, whereas that in burrowers is more aerobic, and that this would be reflected both structurally and functionally in their respiratory gas exchange pathway. We used an experimental design consisting of two burrowing scorpionids (Scorpio fuscus and S. palmatus), two surface dwelling buthids (Hottentotta judaicus and Leiurus hebraus) and a burrowing buthid (Buthus israelensis). Surfacedwelling buthids exhibited the highest running speeds, but also higher rates of fatigue. They also had higher respiratory gas exchange ratios, compared with scorpionids, suggesting higher reliance on anaerobic metabolism. The rapid emission of excess CO2 in buthids is correlated with higher carbonic anhydrase activity, and larger book lung surface area. In contrast, higher P50 values for scorpionid hemocyanins may serve to enhance oxygen unloading in the working muscle during aerobically-fueled burrowing.

A13.142 BRIDGING THE KNOWLEDGE

A13.143 EFFECTS OF AMINO ACIDS ON OLFACTORY DEVELOPMENT AND PLASTICITY IN AGE – 0 LAKE STURGEONACIPENSER FULVESCENS

Friday 7 July 2023

09:00

Tyler Edwards (University of Manitoba, Canada), Mark Fry (University of Manitoba, Canada), Gary Anderson (University of Manitoba, Canada)

edward32@myumanitoba.ca

GAP IN

OF ENERGY ALLOCATION IN TROPICAL FISH: INSIGHTS FROM MACHINE LEARNING

Thursday 6 July 2023 17:45

Min-Chen Wang (Institute of Cellular and Organism Biology Academia Sinica, Taiwan), Ching-Wei Wang (Biodiversity Research Center Academia Sinica, Taiwan), Tzu-Hao Lin (Biodiversity Research Center Academia Sinica, Taiwan), Yung-Che Tseng (Institute of Cellular and Organism Biology Academia Sinica, Taiwan)

mcwinlab@gmail.com

As the physiological processes are energy-limited, organisms adjust their energy allocation to meet the continuous physiological regulations throughout the annual cycle. In anisogamous species, it is typical for females to invest more energy in the form of yolk during gamete production compared to males. In contrast, males tend to invest less in gamete production than females. The inherent difference between males and females results in the difference in energy allocation strategies. This study collected and analyzed the serum samples of tropical tilapia (Oreochromis mossambicus) to investigate gender differences throughout the annual cycle. And the annual metabolites variations and the significance of each metabolite in certain months were determined by the machine-learning algorithms. The comprehensive analysis showed the sexual difference in amino acids in serum of tilapia serum prior to the reproduction season. This study is expected to help bridge the knowledge gap regarding how different sexes of tilapia adjust their energy budget for homeostasis in a seasonal cycle and provide valuable information that can benefit aquaculture improvement in tropical/subtropical areas.

The rearing environment plays an essential role in the phenotypic development of all animals. However, little research has examined how chemical stimuli in the environment may affect the development and plasticity of the olfactory system in fishes. In fishes, the olfactory epithelium contains three olfactory sensory neurons (OSNs) microvillous, ciliated and crypt. Mature OSNs are present in the olfactory epithelium 5.5 days post-fertilization (DPF) in Acipenserids. The goal of this study was to determine the developmental plasticity of olfactory epithelia in developing lake sturgeon (Acipenser fulvescens) by manipulating early-rearing environments with different amino acids (L-alanine, L-lysine, or L-glutamic acid). We raised larvae in four re-circulating tanks and treated the tanks from 10-20 DPF before exogenous feeding with one of the selected amino acids at a concentration of (~5 x10-5 M). We measured mRNA transcript abundance of the microvillous OSN marker (TRPC2) and receptor genes (V2R26, V2R1) and ciliated OSN marker (OMP) and receptor genes (OR1, TAAR1) throughout development at 10, 21, 26, 31, 50, 65 and 80 DPF. At ~1year post-fertilization imprinting effects to treatment amino acids were measured using electro-olfactogram. Previous observation suggested acute exposure affected mRNA transcript abundance of olfactory receptors. We explored if the early-rearing environment affects the receptor abundance and reception of olfactory stimuli. This may support the activity-dependent survival of OSNs and suggest that simplistic hatchery environments may lead to the development of low-performance olfactory phenotypes in a hatchery setting.

A13.144 IS OLFACTION IN THE COASTAL YELLOW SHORE CRAB IMPACTED BY OCEAN ACIDIFICATION?

Friday 7 July 2023 09:00

Elissa Khodikian (University of Toronto Scarborough, Canada), Gwangseok R Yoon (University of Toronto Scarborough, Canada), Cosima S Porteus (University of Toronto Scarborough, Canada)

elissakhodikian@hotmail.com

Coastal upwelling events bring deeper high carbon dioxide (CO2) waters to the surface, making coast lines particularly variable in CO2 Additionally, atmospheric CO2 is absorbed by our oceans, leading to ocean acidification with end-of-century levels predicted to increase to three times current day levels. Therefore, coastal areas are already a more variable environment, and will become even more so in the future. Ocean acidification has been shown to alter olfactory behaviours such as foraging and predator sensing in crustaceans. However, data on coastal species that already experience fluctuating and higher CO2 levels, is scarce. Yellow shore crabs, Hemigrapsus oregonensis, a species found on the Pacific coast, were exposed for 14-days to

SEXUAL DIFFERENCES

control (~700μatm, pH=8.0, current CO2 levels), medium (~1500μatm, pH=7.7, current upwelling events), and high (~3000μatm, pH=7.1, future upwelling events) CO2 levels. Behaviour was then analyzed including baseline locomotion, odorant preference, and time to locate odorant source with an attractive food cue, putrescine (butane-1,4-diamine).

Crabs exposed to medium and high CO2 levels took three times longer to locate the odorant source when compared to control crabs. Similarly, crabs exposed to medium and high CO2 levels took longer to indicate preference to the odorant side. There were no significant differences in baseline locomotion, indicating this is an impairment in olfaction rather than a result of changes in metabolism. Effect of current upwelling events demonstrated olfactory impairment indicating lack of adaptation to current levels and with upwelling events predicted to increase in length and severity, this impairment will likely worsen.

A13.145 PRESENCE OF NEUROEPITHELIAL CELLS ACROSS

Friday 7 July 2023 09:30

Liam

liam.tigert@mail.utoronto.ca

Being able to sense oxygen in the environment is an important ability for many species. For fishes, neuroepithelial cells (NECs) are specialized neurotransmitter containing cells located in the gills which are able to detect oxygen. They do so by releasing neurotransmitters such as serotonin onto efferent nerves giving rise to a behavioural or cardiorespiratory response. These cells have been described in various species, including those in the Orders; Petromyzontiformes, Amiformes, Anguilliformes, Cypriniformes, Osteoglossiformes, Salmoniformes, among others. However, these NECs have predominantly only been described in freshwater fishes, with the exception of one species that lives in brackish environments. Due to the nature of NECs being physiologically important, and found across various taxa, including primitive lineages, it is possible that they are a synapomorphy that arose early in the evolution of fishes. For this study, we investigated four, diverse marine species, including Eptatretus stoutii,Squalus suckleyi, Citharichthys sordidus and Gasterosteus aculeatus. Using immunohistochemistry, we found NECs in the gills of S. suckleyi, C. sordidus, and G. aculeatus, but not the hagfish, E. stoutii. This is the first time NECs have been reported in entirely marine species of teleosts, as well as the first time NECs have been reported in a cartilaginous fish. These findings, paired with previous studies suggest that it parsimonious to assume that NECs evolved in the common ancestor of Petromyzontiformes, Chondricthyes and Osteichyes, and are absent in Myxiniformes.

A13.146 BAT SONOTYPE AS A NOVEL INSIGHT INTO THE CONGO BASIN RAINFOREST DYNAMIC

Friday 7 July 2023 09:45

Yoba Alenga (Congolese Youth Biodiversity Network, Congo (Democratic Republic))

yobaalenga96@gmail.com

relationships between bats and their preferred habitats and also to identify functional role of bats captured or recorded in their habitat. A total of 42 bats were captured, belonging to 13 species, including 5 species of frugivorous bats and 8 insectivorous bats.

The frugivorous bats - namely the speciesScotonycteris bergmansi, Casinycteris arginnis, Myonycteris torquataandEpomops franqueti- were associated with dispersal of 16 plant species in the Yangambi Man and Biosphere Reserve (Aidia micrantha, Allanblackia floribunda, Anonidium mannii, Barteria nigritana, Canarium schweinfurthii, Coelocaryon preussi, Dacryodesedulis, Mammeaafricana,Maranthesglabra, Microdesmisyanfungana, Musangacecropioides, Pycnanthusangolensis, Staudtiagabonensis, Strombosiagrandifolia, StrombosiopsistetrandraandPandaoleosa) while the species Megaloglossuswoermanniensures the pollination of the speciesMaranthesglabra.

Acoustic monitoring revealed the presence of 11 sonotypes namely of the following species:Chaerephonpumilus, Macronycterisgigas, Macronycterisvittatus, Doryrhinacyclops, Rhinolophusfumigatus, Neoromicianana/ Scotophilusdinganii, Pipistrellusnanulus,Pipistrellusrueppellii, Nycterisarge, MyotisbocagiiandGlauconycterissuperba.

The type of habitat (primary forest) significantly increases the foraging activity of bats. A medium to high density of the understorey and a medium opening of the canopy have a significant influence on bat activity and call structure. Complementarity of acoustic monitoring and capture is crucial to understand the mechanisms governing aggregation of bats assemblages in order to assess their activity and the ecosystem services they provide.

A13.147 RECONSTRUCTING THE VISUAL CAPACITY OF THE MINIATURE TABACO WHITEFLY

Friday 7 July 2023 10:00

Tomer Urca (University of Rostock, Germany), Fritz Olaf Lehmann (University of Rostock, Germany)

tomerurca@gmail.com

In the course of evolution, many insect species have gone through a process of miniaturization resulting in body lengths of under a millimeter. This led to a simplification of their compound eyes including a structural reduction in the number of ommatidia. As the optical resolution of compound eyes depends on the number of ommatidia, small animals should be limited in their visual capacity for object recognition and optomotor behaviors. Here we present a detailed evaluation of the unique two-part eye structure of the millimeter-long tobacco whitefly, Bemisia tabaci. Whitefly heads were three-dimensionally reconstructed from µCT scans and analyzed using self-written MATLAB code. From the digitized coordinates of morphological markers, we derived the eye’s geometrical properties

MARINE FISHES SHINES LIGHT ON THE EVOLUTION OF OXYGEN SENSING.

R Tigert (University of Toronto Scarborough, Canada), Cosima S Porteus (University of Toronto Scarborough, Canada), Deep Soor (University of Toronto Scarborough, Canada)

including interommatidial angles and visual axes (gaze). We further determined the position of the eye during locomotion by analyzing high-speed videography of walking and flying whiteflies. These analyses allowed us to construct ommatidial projection maps according to eye position. We found that each compound eye has a length of approximately 100 µm and consists of approximately 70 ommatidia and that visual resolution and ommatidia properties changed between the two eye parts. The two eye parts face a different directions as the orientation of the eyes changed between walking and flying, implying different functionality between the two parts according to the form of locomotion. Altogether, our study uncovered several novel properties of insect miniature eyes and predicts a reduction in control capacity during vision-guided flight behaviors.

A13.148 THE ROLE OF SENSORY AND HAEMATOLOGICAL FACTORS DURING THERMAL ACCLIMATION IN FISHES

Friday 7 July 2023 10:15

Robine H.J. Leeuwis (Norwegian University of Science and Technology, Norway), Rachael Morgan (University of Bergen, Norway), Anna H. Andreassen (Norwegian University of Science and Technology, Norway), Lorena Silva-Garay (Norwegian University of Science and Technology, Norway), Zara-Louise Cowan (Norwegian University of Science and Technology, Norway), Eirik R. Åsheim (University of Helsinki, Finland), Jérémy De Bonville (University of Montreal, Canada), Sandra A. Binning (University of Montreal, Canada), Graham D. Raby (Trent University, Canada), Fredrik Jutfelt (Norwegian University of Science and Technology, Norway)

robin.leeuwis@ntnu.no

Like other ectotherms, fishes often exhibit a remarkable capacity to acclimate to a range of environmental temperatures. However, the specific regulatory/signalling factors in the thermal acclimation process are not well understood. In this study, we examined the roles of superficial thermoreception (e.g. via subcutaneous sensory neurons) and blood plasma components (e.g. hormones) in two experiments on two temperate fish species. In the first experiment, we exposed 16°C acclimated goldsinny wrasse (Ctenolabrus rupestris) to a ‘dipping treatment’ of immersion for 10 seconds in an 8°C (cold), 16°C (control) or 24°C (warm) water bath, repeated 5 times/day for 5 days. The brief immersion time allowed for skin, but not deep muscle and internal organs, to equilibrate with the bath temperature. In the second experiment, we submitted 16°C acclimated Atlantic cod (Gadus morhua) that were surgically outfitted with intraperitoneal catheters to a ‘transfusion treatment’ by injecting plasma from 8°C (cold), 16°C (control) or 21°C (warm) acclimated donor cod, for 10 times over 4 days. Donor cod were acclimated for 24 hours before blood collection. Following the dipping and plasma transfusion treatments, we measured the critical thermal maximum (CTmax ) of all fish, and the standard metabolic rate (SMR) in cod. Neither the dipping nor the transfusion treatment affected CTmax , despite differences in CTmax among donor cod acclimation groups. The analysis of SMR is still ongoing. Based on these preliminary results, we found no evidence of superficial thermoreception and plasma components as sensory and haematological factors driving thermal acclimation in these fishes.

A13.149 OUT OF WATER AND NOWHERE TO GO. NITROGENOUS WASTE HANDLING IN THE LIMPET FOLLOWING VOLUNTARY EMERSION.

Friday 7 July 2023 12:00

Jonathan M Wilson (Wilfrid Laurier University, Canada), Dirk Weihrauch (University of Manitoba, Canada), Chris M Wood (University of British Columbia, Canada)

jmwilson@wlu.ca

The mask limpet Tectura persona is a univalve mollusk commonly found in protected rocky areas in the high and mid-intertidal zones and can thus frequently be emersed. During these periods of emersion, a small volume of water is held under the shell to avoid desiccation and represents a finite sink for the excretion of waste products. Aquatic molluscs are generally ammoniotelic and thus ammonia accumulation could pose problems since it is neurotoxic. We observed that voluntarily emersed limpets were able to accumulate ammonia (16.9±6.3mM (TAN) total ammonia-nitrogen) up to 38mM in their shell water, which was far higher than body fluid levels (2.9±1.0mM). This was accomplished through an acidification of the seawater (pH7.90) to as low as pH5.04 to maintain an outward NH3 gradient. Ammonia excretion rates were also higher in emersed animals. To address the question of the mechanism(s) of excretion we examined limpet gills by immunohistochemistry using heterologous antibodies and fluorescence microscopy. The parallel rows of gill lamellae with transverse furrows are lined by a simple columnar epithelium of ciliated cells. Na+ /K+ -ATPase was present basolaterally throughout the epithelium. In contrast, both the Rh glycoprotein ammonia transporter and Na+ / H+ -exchanger (NHE) were found apically localized to a population of isolated cells scattered throughout the gill epithelium. These results suggest that a specialized cell type might be involved in the ammonia and acid excretion based on the presence of the Rh glycoprotein and NHE, respectively. The vacuolar proton pump may present an additional mechanism for acidification. Our findings will be discussed.

A13.150 PHARMACOLOGICAL STUDIES REVEAL AMMONIA-DEPENDENT PH

Friday 7 July 2023

12:15

Inga Petersen (Christian-Albrechts-University Kiel, Germany), Marian Y Hu (Christian-Albrechts-University Kiel, Germany)

I.petersen@physiologie.uni-kiel.de

Analogous to the situation in several lepidopteran and dipteran insects also the larval stages of some echinoderms and hemichordates (ambulacraria superphylum) evolved highly alkaline midguts up to pH 10.5. Despite its pivotal role in species´ immunity, digestion physiology and sensitivity to changes in seawater pH, the underlying epithelial transport mechanisms remain largely unknown.

We measured intracellular pH regulation of midgut cells and pH maintenance of midgut fluids in the sea urchin larva in the presence of different inhibitors targeting acid-base transporters.

Measurements of midgut pHi regulatory capacities under different inhibitor treatments demonstrated that vacuolar H+ -ATPase (bafilomycin a1), carbonic anhydrase (acetazolamide), anion-exchangers (4,4′-Diisothiocyano-2,2′-stilbendisulfonsäure (DIDS)) and soluble adenylyl cyclase (KH7) play an important role in cellular acid-base regulation.

Using ion-selective microelectrodes (ISMs) we found that midgut alkalization is reduced by bafilomycin a1 and completely abolished by KH7 while DIDS only inhibited alkalization when applied from the luminal side. Interestingly, high external ammonia (HEA; 1.5 to 5 mM) also decreased midgut pH suggesting a coupling of NH3 /NH4 + transport to midgut alkalization. Single cell transcriptomics revealed the presence of a RhP expressed in midgut cells that is stimulated on the mRNA level under acidic conditions, indicating an involvement in defending midgut pH.

Ammonia excretion rates are affected by bafilomycin a1 and KH7 suggesting an involvement of sAC and H+ -ATPase in the excretion of nitrogenous waste products.

This comprehensive pharmacological analysis has led to a new working model of midgut

A13.151 THE ROLE OF THE INTESTINAL SPIRAL VALVE ON WHOLE-BODY NITROGEN HOMEOSTASIS IN MARINE ELASMOBRANCHS

Friday 7 July 2023 13:00

J. Lisa Hoogenboom (University of Manitoba, Canada), W. Gary Anderson (University of Manitoba, Canada)

lisa.hoogenboom@umanitoba.ca

Marine elasmobranchs are ureosmotic, retaining large concentrations of urea (> 300 mM) to counterbalance the osmotic pressure of the external environment. To better understand this unique urea-centric osmoregulatory strategy, our research focused on nitrogen acquisition across the elasmobranch spiral valve, and its contribution to the wholebody nitrogen balance. We examined the uptake and incorporation of dietary nitrogen (7 mM 15 NH4 Cl) in North Pacific spiny dogfish. Samples (spiral valve, liver, muscle, and plasma) were collected at 20, 48, 72, and 168 h post-feeding, and analyzed for enrichment of 15 N in ammonia, urea, glutamine, bulk amino acids, and protein. We demonstrated that within 20 h post-feeding, dietary 15 N was acquired, circulated, and incorporated into all tissues examined, and retained for at least 7 days. We also investigated the contribution of dietary nitrogen to the synthesis of urea by examining the activity and mRNA abundance of four ornithine urea cycle (OUC) enzymes (glutamine synthetase, GS; and arginase, ARG; carbamoyl phosphate synthetase III, CPS III; and, ornithine transcarbamylase, OTC). Lastly, we examined mechanisms of nitrogen movement across the spiral valve by quantifying the transcript abundance of a urea transporter (UT) and two ammonia transporters (Rhp2, Rhbg). Histochemical staining identified Rhp2 expression along the apical brush-border membrane of the spiral valve epithelial cells, and UT along the basolateral membrane and blood vessels. This work contributes to our understanding of how marine elasmobranchs acquire dietary nitrogen, transport it across the spiral valve, incorporate it into various tissues, and use it to synthesize multiple nitrogenous compounds.

A13.152 ACIDIC FRESHWATER STIMULATES AMMONIA SYNTHESIS AND AFFECTES SUBSEQUENT ENERGY METABOLISM IN JAPANESE MEDAKA

Friday 7 July 2023 13:15

Hsin-Ju Chuang (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), Ling Chiu (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan), PungPung Hwang (Institute of Cellular and Organismic Biology Academia Sinica, Taiwan)

ruby840504@gmail.com

Climate changes and anthropogenic activities cause environmental acidification in fresh water as in marine. Fishes are the aquatic vertebrates directly encountering environmental acidification. Excess acid disturbs fish body fluid acid-base balance, which is essential for physiological homeostasis and cellular activities. To conquer acidic stress, activating ammonia excretion to enhance net acid secretion is a conserved strategy developed in vertebrates including ammonotelic fishes. Mammalian kidney is the sole orang conducting glutaminase (GLS)-mediated ammoniagenesis, ammonia excretion, and subsequent gluconeogenesis to cope with internal acidosis. In teleosts, ammonia is produced in all the organs, and the gills excrete most of ammonia. In the present study, medaka, different from mammals, activated systemic GLS-ammoniagenesis and interorgan energy mobilization under acidic stress. The muscle and liver are major energy pools for ammoniagenesis. After 7-day acclimation to acidified freshwater, the mass of muscle was decreased with the loss of carbohydrate and protein while the enlarged liver accumulated carbohydrate, protein, and lipid. Transcriptome analyses revealed corresponding energy metabolic changes to reinforce the macronutrient profiles in the liver and muscle. Taken together, medaka developed efficient mechanisms of GLS-mediated ammoniagenesis, ammonia excretion, and energy mobilization to cope with acidic stress. The muscle supplies amino acids for ammoniagenesis, and subsequently the metabolic intermediates in the muscle are transported to the liver for energy storage. Ammoniagenesis and accompanied interorgan energy mobilization suggest a possible trade-off energy reallocation to increase fish fitness for population sustainability in acidified environments.

A14 EXPERIMENTAL PALAEOBIOLOGY - BRINGING FOSSILS "BACK TO LIFE"

ORGANISED BY: JAMIE MACLAREN (UNIVERSITY OF ANTWERP), NARIMANE CHATAR (UNIVERSITY OF LIEGE), PETER FALKINGHAM (LIVERPOOL JOHN MOORES UNIVERSITY), SOPHIE REGNAULT (PRIFYSGOL ABERYSTWYTH UNIVERSITY)

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

A14.1 A PIKA INTO LAGOMORPH EVOLUTION: A BIOMECHANICAL ANALYSIS OF PALAEOLAGUS HAYDENI

Wednesday 5 July 2023 POSTER SESSION

Amber P Wood-Bailey (University of Liverpool, United Kingdom), Alana C Sharp (University of Liverpool, United Kingdom), Philip G Cox (UCL, United Kingdom), Nathan S Jeffery (University of Liverpool, United Kingdom)

apwb@liverpool.ac.uk

Lagomorphs have a long and specious evolutionary history, dating to around the KPg extinction; however, they remain remarkably conservative in their morphology throughout evolutionary time. The largest morphological distinction is between the two families: Ochotonidae (pikas) and Leporidae (rabbits and hares).Whilst many fossils can be clearly assigned to either family (or other now-extinct families), Palaeolagus has caused taxonomic difficulty: once thought to sit outside of the extant families, but now considered a leporid. However, P. haydeni features a mosaic of cranial morphological traits that are ochotona-like, leporid-like and some that are unique. Essentially, Palaeolagus can be described as having a rabbit-like anterior cranium and a pika-like posterior cranium.

Here, we used finite element analysis to compare the cranial strains induced during feeding between a pika (Ochotona princeps), a rabbit (Pronolagus rupestris) and a new, undescribed P. haydeni specimen to ascertain whether, in terms of biomechanical function, the Palaeolagus crania reflects the mosaic nature of the anatomical elements.

The distribution of cranial strains in Palaeolagus suggest that the anterior portion of the cranium is performing much like the anterior portion of the rabbit, having a longer rostrum and lateral fenestrations. The posterior portion, however, is performing much like the posterior portion of the pika specimen, without an abrupt boundary between defined by the intracranial joint in leporids. In terms of mechanical function, this could suggest that Palaeolagus was moving and eating like a rabbit but perhaps with small pika-like ears, and a bauplan that’s more like a pika.

A14.2 THE EQUID LOCOMOTOR TRANSITION THROUGH THE LENS OF EXPERIMENTAL PALAEOBIOLOGY

Wednesday 5 July 2023 POSTER SESSION

Jamie A MacLaren (Universiteit Antwerpen, Belgium), Mariëlle Kaashoek (Universiteit Antwerpen, Belgium), Tim De Ridder (Universiteit Antwerpen, Belgium), Kwinten Vangeel (Universiteit Antwerpen, Belgium), Raf Claes (Universiteit Antwerpen, Belgium), Peter Aerts (Universiteit Antwerpen, Belgium), Sandra Nauwelaerts (Universiteit Antwerpen, Belgium)

jamie.maclaren@uantwerpen.be

The changes in the locomotor anatomy of equids (Equidae: horses, zebras and allies) represents an incredibly recognisable and widely cited evolutionary transition. Over the past 10 years, researchers at the University of Antwerp have worked on developing our understanding of equid locomotion and the shift from tetradactyly (four-toes) to monodactyly (one-toe) from conceptual, anatomical, experimental, and palaeontological standpoints. Starting from anatomical and kinematic investigations of modern taxa to establish an interspecific comparative framework, our investigations have assessed kinematic variation in monodactyl equids, range of motion and helical axis quantification in monodactyl and tetradactyl perissodactyls, pressure distribution beneath the tetradactyl perissodactyl manus, monodactyl vs. tetradactyl muscle function-spaces, a refreshed take on the rationale behind equid digit reduction, and simulations of side-toe utility at midstance through the fossil record of equids. Building an extant phylogenetic bracket for the earliest equids was the vital first step for this project. This has gradually been achieved through the comparative assessment of modern monodactyl equids alongside a revision and novel investigation of modern tetradactyl perissodactyls: tapirs (Tapiridae). While not perfect analogues for early equids, the tapir locomotor apparatus has proven an invaluable source of information for establishing a greater understanding of extinct ancestors of horses (and other perissodactyl groups), and continues to be a rich source of new anatomical and functional information which can be used to infer the (palaeo)biology of extinct perissodactyls.

A14.3 VALIDATING MUSCULOSKELETAL MODELS: AN ECHIDNA CASE STUDY

Wednesday 5 July 2023

POSTER SESSION

Sophie Regnault (Aberystwyth University, United Kingdom), L Fahn-Lai (Harvard University, United States), Stephanie Pierce (Harvard University, United States)

sor24@aber.ac.uk

Musculoskeletal computer models are useful to explore hypotheses about extinct animals, both individually (e.g. what could this animal do?) and as populations through evolutionary time (e.g. how have form & function changed, do any changes underpin the success of lineages?). Models require validation, with experimental data from extant animals, for results and inferences to be evidence-based.

Particularly valuable for validation is the study of comparative form & function (across and between phylogenetic groups), and the use of animals with ‘unusual’ form &/or function (e.g. extremes of body plan or performance, strange/underrepresented anatomical features). Such examinations allow us to investigate the constraints of computer models or biological functions, and phylogenetically bracket fossil organisms.

Here, we present a model of an echidna alongside experimental data used to validate it. This echidna model formed part of a series of extant and extinct animal models used to examine mammalian forelimb evolution, and the echidna was a useful datapoint due to their unusual anatomy (some features very similar to extinct relatives of mammals), biomechanics (sprawling, rolling gait) and phylogenetic placement (outgroup to therian mammals).

We used the model to discuss pertinent questions about traditional model-building approaches and their application to extinct animal reconstructions: 1) does a ‘light touch’ approach to muscle wrapping replicate in-situ muscle pathways; 2) how accurate are range of motion predictions; 3) how accurate are muscle moment arm predictions; and 4) how does incorporation of muscle architecture data change functional interpretations?

A14.4 EXPERIMENTAL DESIGN OF SPINE’S FUNCTION ACROSS THE EVOLUTION OF BIRDS

Wednesday 5 July 2023 POSTER SESSION

Alejandro Pérez-Ramos (Universidad de Málaga, Spain), Francisco J. Serrano (Universidad de Málaga, Spain), Jordi Marcé-Nogué (Universitat Rovira i Virgili, Spain), Borja Figueirido (Universidad de Málaga, Spain)

pera@uma.es

Achievement and refinement of flight in birds and dinosaurian allies has been extensively discussed in the literature with main focus on aerodynamics, anatomy and morphology of the wings and flight feathers. However, the biomechanical role of the spine during flight and how this structure evolved are scarcely known. Here we assess the biomechanical impact of the spinal regionalization to support flight-related stresses. Different spine configurations were constructed for key taxa and nodes of Aves:Archaeopteryx, Enantiornithes,Apsaravis,Ichthyornis, and Neornithes. Column models were generated using repeated units of basic geometry (i.e., cube) to proxy the vertebrae and by maintaining the kinetic

and biomechanical properties of each region. Using finite element analysis we quantified the strength of each configuration to support the bending stress resulting from the body weight at the center of masses, and the transmission of wing-flapping stress to the trunk. Our results demonstrate that the spinal configuration of modern birds (i.e., Neornithes) are better to support flight-related stresses, which allowed more stable flight with respect to other non-neornithine birds during the Cretaceous.

A14.5 AN INNOVATIVE FORCE SENSOR TECHNOLOGY TO STUDY THE EVOLUTION OF GRASPING SPECIFICITIES IN ARBOREAL MAMMALS

Wednesday 5 July 2023 POSTER SESSION

Séverine L. D. Toussaint (Humboldt Universität zu Berlin, Germany), Luca Morino (Muséum National d'Histoire Naturelle, France), Artémis Llamosi (UMR 7057 Sorbonne Université, France), Georg Neye (Humboldt Universität zu Berlin, Germany), John A. Nyakatura (Humboldt Universität zu Berlin, Germany)

severine.toussaint@hu-berlin.de

Early primates appeared in an arboreal context about 60 million years ago and acquired unique characters such as opposable first digits and nails instead of claws. However, the initial function(s) and sequence of appearance of these specificities are still unclear. Studying the biomechanics of movement and forces exerted by the hands and feet during arboreal locomotion in extant primates and non-primate arboreal mammals provides insight into the impact of the arboreal lifestyle on their morpho-functional adaptations. For this purpose, we developed an innovative force sensor technology allowing to measure the direction and intensity of contact forces, with a spatially resolved and dynamic resolution. This patented technology allows the design of sensors with variable shapes and sizes and can be used in natural environments because it is autonomous, transportable and made of biocompatible materials. We designed a version of this system in the shape of a branch to study the biomechanics of grasping during arboreal locomotion in 5 primates, 1 rodent and 1 carnivoran in zoological parks. These data will notably help elucidate whether the nails of primates allow them to apply more force compared to the claws of other mammals, by quantifying for the first time the variation of forces exerted by the different anatomical regions of the phalanges in those species. This study will ultimately help inferring functional adaptations in fossils that present preserved hands and feet. This technology and experimental methodology have multiple applications, ranging from biomechanics to haptics, health and robotics.

A14.6 STUDY OF THE SECOND MECHANORECEPTIVE ORGAN OF BIRDS,

Wednesday 5 July 2023

POSTER SESSION

Idriss PELLETAN (Muséum national d'Histoire naturelle - CNRS, France), Raphaël CORNETTE (Muséum national d'Histoire naturelle - CNRS, France), Anick ABOURACHID (Muséum national d'Histoire naturelle - CNRS, France)

THE LSO

idriss-clement.pelletan@mnhn.fr

The Lombosacral organ (LSO) is an mechanoreceptor organ unique in birds. It is located along the spinal cord in the synsacrum. The organ consists of a glycogen body in the center of the structure, dorsal to the spinal cord. Accessory lobes consisting of motor neurons, are distributed in pairs ventrolaterally along the neural canal. Ligaments support the entire LSO and channels arranged dorsolaterally along spinal cord. While its role in maintaining balance has been demonstrated in pigeon, and the biomechanical functioning has been explored on two species. Its functioning, its origin and its correlation with the ecology of the species remain discussed. The relationship between the morphology of the LSO and the ability to perch in birds has been proposed. Its presence known in the fossil record, but the evolutionary history of the LSO remains unknown. In order to understand the evolution of the LSO, we are investigating whether there is a correlation between the shape of the LSO, the shape of the pelvis and ecological indicators, considering the phylogeny. We used methods of geometric morphometry, comparative phylogeny and ecological indicators such as the main mode of locomotion. We show that the number of vertebrae constituting the synsacrum is variable and corelated to phylogeny with locomotion mode. We also show a correlation between pelvis shape, LSO endocast and mode of locomotion. In particular, birds that mainly perch have a larger LSO independently of a mass effect.

A14.7 EVOLUTIONARY ORIGINS OF MAMMALIAN AXIAL FUNCTION REVEALED THROUGH DIGITAL BENDING

EXPERIMENTS

Thursday 6 July 2023 14:30

Katrina Jones (University of Manchester, United Kingdom), Kenneth Angielczyk (Field Museum of Natural History, United States), Stephanie Pierce (Harvard University, United States)

katrina.jones@manchester.ac.uk

The origin of mammals from non-mammalian synapsids (NMS) represents an iconic locomotor transition, characterized by a change from reptile-like abducted limbs and lateral movements of the backbone to mammal-like adducted limbs and sagittal backbone movements. However, recent research has called into question the lateral-to-sagittal functional shift in NMS, instead suggesting that basal synapsids displayed a distinct functional regime and ancestral condition not observed in extant reptiles. To investigate this idea further, we usedAutobend,a technique for estimating vertebral osteological range of motion (oROM) from skeletons using digital modeling.We appliedAutobendto seven extant mammal and reptile species and 8 exceptionally preserved non-mammalian synapsids to estimate vertebral oROM and intervertebral joint stiffness. Results revealed a clear distinction between extant mammals and reptiles in oROM, with reptiles emphasizing lateral bending and mammals sagittal bending as expected. While most extant taxa exhibited relatively similar levels of stiffness in lateral and sagittal directions, extant lizards and salamanders displayed much more compliance in lateral bending and lower stiffness overall, in keeping with their observed axial kinematics. The mammalian condition of sagittal mobility accompanied by axial twisting in the anterior column is first observed in the crownward tritylodontid cynodontKayentatherium. Given the strong association between sagittal bending and asymmetric gaits in mammals, these results provide an important first step in reconstructing the evolution of synapsid locomotor patterns.

A14.8 EXPERIMENTAL TEST OF DENTAL MASTICATORY EFFICIENCY IN URSIDAE.

Thursday 6 July 2023 15:15

Alejandro Pérez-Ramos (Universidad de Málaga, Spain), Jack Tseng (University of California Berkeley CA, United States), Alejandro Romero (Universidad de Alicante, Spain), Borja Figueirido (Universidad de Málaga, Spain)

pera@uma.es

In the field of dental biomechanics, many works are based on virtual analysis. Rarely has it been possible to physically test the variables hypothesized to be responsible for the evolution of dental complexity and its correlation with increased functional efficiency. In this work we apply experimental dental biomechanics in a macroevolutionary case study using the family Ursidae. In order to physically measure dental masticatory efficiency, a multi-stage experiment was designed. Dental casts of each species were printed in resin with tooth-like material properties and food models with a property similar to the woody plant material were fabricated. Biting using both carnassial (P4-m1) and molar (M1/m2) bite positions were simulated by means of an eletromechanical testing frame. Force and time to fracture data indicate that species with greater complexity and larger occlusal area produced higher efficiency of the molar region with respect to the premolar region. Experimentally derived masticatory biomechanical efficiencies are similar in species such as giant panda and extinct cave bears that are known or inferred to utilize harder or more abrasive materials. These findings provide an additional line of evidence for dental formfunction linkages, and support previous work on deciphering the diet of cave bears using dental topographical analysis. Taken together, these consilient data demonstrate a strong correspondence between dental topographical and biomechanical variables and a more tough/ woody diet in bears.

Thursday 6 July 2023 15:30

Axelle Gardin (PALEVOPRIM (UMR 7262 CNRS and Université de Poitiers), France), Manuel J Salesa (Departamento de Palaeobiología Museo Nacional de Ciencias Naturales-CSIC, Spain), Gema Siliceo (Departamento de Palaeobiología Museo Nacional de Ciencias Naturales-CSIC, Spain), Mauricio Antón (Departamento de Palaeobiología Museo Nacional de Ciencias Naturales-CSIC, Spain), Juan F Pastor (Departamento de Anatomía Facultad de Medicina Universidad de Valladolid, Spain), Louis De Bonis (PALEVOPRIM (UMR 7262 CNRS and Université de Poitiers), France)

axelle.gardin@univ-poitiers.fr

In the 1970s, Itardies, one of the fossil sites in the Quercy Phosphorites (southwestern France), yielded an impressive amount of fossils belonging mostly to Amphicynodon leptorhynchus, a small carnivoran

A14.9 BRINGING AMPHICYNODON BACK TO LIFE: FUNCTIONAL ANATOMY AND RECONSTRUCTION OF A SMALL CARNIVORAN FROM THE QUERCY PHOSPHORITES (LOWER OLIGOCENE, FRANCE)

from 30 million years ago. The family Amphicynodontidae became extinct without leaving any descendant, but was particularly diversified during the lower Oligocene in the Northern Hemisphere. However, the ecology of these carnivorans was still largely unexplored, especially concerning their locomotor behaviour. The numerous fossil remains of A. leptorhynchus from Itardies allowed the first studies of the postcranial skeleton of an Amphicynodontidae and the exploration of its locomotor adaptations and lifestyle. By comparison to the skeletons of modern climbing, running, fossorial and generalist modern carnivorans, through anatomical descriptions and morphometric studies, we highlight the outstanding climbing adaptations of A. leptorhynchus. To provide a picture of this poorly-known carnivoran and go deeper into the interaction between this animal and its environment, we also offer a hypothetical reconstruction of its appearance. This paleoartistic reconstruction, presented in different process steps, illustrates its inferred locomotor behaviour in its environment, based on the results of our functional study and the observation of modern carnivorans (movement, musculature, coat...).

A14.10 PALEOMIMETICS: BIOMIMETIC DESIGN APPROACH INSPIRED BY FOSSILS AND EVOLUTIONARY PROCESSES

Thursday 6 July 2023 15:45

Valentina Perricone (Department of Engineering University of Campania Luigi Vanvitelli Aversa Italy, Italy), Carla Langella (Department of Architecture University of Naples Federico Naples Italy, Italy), David Kisailus (Department of Materials Science and Engineering University of California, United States)

valentina.perricone@unicampania.it

In biomimetic design, functional details, principles and processes are the most aspired features that can be found in nature. Research on these elements is carried out through the application of modern biological sciences without giving importance to the generative mechanism behind them: evolution. To deeply understand the meaning of specific morphologies, structures and processes, and thus improving their analogously transfer in products, it is important not only to describe, analyze and test their behavior, but also understand the need that has led to evolve these features. The study of functional characteristics and their variations across the course of evolution is the main topic of paleontological investigation. Paleontology follows the variations of organisms beginning from single functional elements to composite systems, up to modifications of the entire anatomy. This approach can considerably improve the efficiency of biomimetic transfer by analogy of function; but not only, this discipline, as well as biology, can contribute to the genesis of new shapes, textures, structures and functional models for productive and generative processes that could be useful in design improvement. Our research aims to exhibit the potential contribution that paleontology can offer to biomimetic processes integrating specific methodologies and knowledge in a typical bio-inspired design approach. In particular, a hybrid methodology is explained and fossil entities are presented as potential inspirations for different design solutions.

A14.11 THE EARLY BIRD ARCHAEOPTERYX WAS A HIGHLY CURSORIAL SHORT-RANGED FLYER THAT SUPPORTS FLIGHT REDUCTION DURING EARLY FLIGHT EVOLUTION

Thursday 6 July 2023 16:30

Michael Pittman (The Chinese University of Hong Kong, Hong Kong), T. Alexander Dececchi (Mount Marty University, United States), Michael B. Habib (University of California Los Angeles, United States)

mpittman@cuhk.edu.hk

Coarse level reconstruction of powered flight capabilities among early birds and their closest relatives has identified non-avian candidates of powered flight ('raptor' dinosaurs Microraptor and Rahonavis). Data collected using more granular methods are needed to confirm the capabilities of the first powered flyers and to better differentiate their relative flight performance. Ratios of bending strength between the humerus and femur of living birds have predictive power for determining their locomotor behaviour; not only in differentiating between flighted and flightless taxa, but crucially, in predicting the relative degree of flight specialisation among flighted taxa. Here we frame this predictive power around fossil paravian theropods to clarify the relative locomotor performance of the earliest powered theropod flyers. Our results support dromaeosaurids Rahonavis and Microraptor as non-avian candidates of powered flight and show that they were more aerial than the ‘first bird’ Archaeopteryx. Archaeopteryx plots within a mechanical properties space that is exceptionally hind limb dominated, much more so than primarily cursorial but flighted living birds like roadrunners, suggesting that Archaeopteryx was a short-ranged flyer at best. Low-strength gracile humeri, exceptionally high femoral-to-humeral section moduli ratios, and comparative “mis-match” between moderate wing area and low humeral strength recovered in our analysis strongly indicate secondary flight reduction in Archaeopteryx. This study suggests that paravian powered flight evolution was more complex than previously appreciated, with early birds being weak flyers but with powered flight reductions appearing soon after flight originated.

A14.12 WING JOINT MOBILITY ACROSS ORNITHURAE – HOW DID STEM-BIRDS FLY?

Thursday 6 July 2023 16:30

Oliver E. Demuth (University of Cambridge, United Kingdom), John R. Hutchinson (Royal Veterinary College, United Kingdom), Grace Kinney-Broderick (University of Cambridge, United Kingdom), Sharon E. Warner (Royal Veterinary College, United Kingdom), Daniel J. Field (University of Cambridge, United Kingdom)

oed24@cam.ac.uk

Birds can morph their wings with exceptional precision for a variety of tasks. They can change their wing shape and area to generate lift, adjust air flow for manoeuvrability, or to fold and store the wings when on the ground. A strong link exists between wing joint mobility and the flight behaviour of modern birds, with different flight styles

exhibiting different constraints on joint range of motion (ROM). We can investigate ex vivo joint movement and ROM in extant taxa with high fidelity using X-ray Reconstruction of Moving Morphology (XROMM). However, for extinct taxa we are often left with bare bones and no connective or other soft tissues, thus making it impossible to measure potential joint movement directly. Recent advances in implementing and inferring soft-tissue constraints on ROM estimates can overcome these longstanding challenges. Here we present a workflow of how a functionally informative ROM estimate can be obtained for a fossil taxon and how it can be contextualised to draw functional and ecological inferences. We estimate ROM of the wing joints of the crownward stem-bird Ichthyornis dispar and calculate ligamentous constraints on its joint mobility. We then project our Ichthyornis joint mobility data into the ‘EcoPhyloMobilitySpace’ generated from a phylogenetically broad ex vivo XROMM dataset of extant birds, with specimens representing most major clades and a wide range of ecological niches and flight styles. This allows us to infer the flight behaviour of this stem-bird, which has implications for the ancestral flight capabilities of all crown-birds.

A14.13 EXPLORING FUNCTION IN BY-GONE MORPHOSPACE: EVOLVING FRACTAL MORPHOLOGIES IN CEPHALOPODS

Thursday 6 July 2023 17:00

Robert Lemanis (Technische Universität Dresden, Germany), Igor Zlotnikov (Technische Universität Dresden, Germany)

robert_evan.lemanis@tu-dresden.de

Reconstructing function solely from morphology can be a tricky task, especially in palaeontology, where extinct morphologies may not have extant analogues that they can be compared to. Ammonoids represent an interesting case in this regard, possessing traits that place them firmly within familiar Cephalopoda, but exploring realms of morphospace completely unexplored by any modern taxa. How then do we explore the concept of functionality in such unique structures? Ammonite septa tell a multigenerational story of researchers attempting to understand the functionality of the unknown. Septa, the internal walls that divide the conical mollusc shell into discrete chambers, are relatively simple in morphology in most cephalopods, often resembling a bowl in 3D shape. Ammonoids however, evolve extremely complex morphologies that develop fractal-like frills along their edge. Muscle attachments, respiratory surface, buttress, a quickly mineralizing surface to prevent the animal from rocketing out of the shell, all of these have been proposed to be the evolutionary driving force behind this increase in complexity. We propose a different take on these structures. Combining theoretical and tomographic models with linear and nonlinear finite element simulations, we show these structures are capable of significantly increasing the structural stability of the shell and prevent catastrophic buckling due to point loads (predation). Resolving the functional question of septa allows us to use the observed morphological trends in this group to help us understand ecological shifts, evolutionary trends, and extinction selectivity through Earth’s history.

A14.14 THE EXPERIMENTAL EFFECTS OF WAVE PROCESSES ON ARTHROPOD TAPHONOMY: IMPLICATIONS FOR LAGERSTÄTTEN AND SMALL CARBONACEOUS FOSSILS.

Thursday 6 July 2023 17:15

Laura K Devine (University of Portsmouth, United Kingdom), Nicholas J Minter (University of Portsmouth, United Kingdom)

devine.laura@hotmail.com

Taphonomy is the study of the biological, chemical, and physical processes that lead to the remains of an organism becoming a fossil. These processes include decay, transport, and preservation; and it is important to understand them because they affect the preservation quality of certain organisms, as well as the fidelity of fossil assemblages as reflections of organismal communities. Actualistic experiments using analogue organisms provide some of the best ways to study these processes, but they have tended to focus on decay and preservation rather than transport. Arthropods are one of the most diverse and evolutionarily significant phyla of animals on Earth, and so it is important to determine if there are any biases in their fossil record. We conducted taphonomic experiments using a wave-generating flume tank to investigate the effects of the duration of exposure to waves on the decay and disarticulation of the marine arthropod, Ligia oceanica. We used Ligia oceanica as an analogue for segmented, multipodous marine arthropods such as trilobites, which are common as fossils through the Palaeozoic (541-252 million years ago). Our results include identification of the stages of bodily damage and a statistical analysis of the effects of wave action compared to static decay for Ligia oceanica. Future work will expand to analogues for other arthropod groups found as fossils, together with comparison to fossil assemblages in order to identify the processes involved in the formation of an exceptionally preserved fossil “Konservat Lagerstätten” or the disarticulated and fragmented remains of small carbonaceous fossil (SCF) deposits.

A14.15 EXPERIMENTS IN FOSSILISATION AND ADVENTURES IN DECAY

Thursday 6 July 2023 17:30

Robert S Sansom (University of Manchester, United Kingdom)

robert.sansom@manchester.ac.uk

Fossils are essential for reconstructing past life and evolution. However, all fossil data have been intrinsically and unavoidably filtered, distorted, and diminished by fossilisation. Even though fossilisation occurs over geological timescales, we can conduct experiments over laboratory timescales to observe post-mortem taphonomic processes, and thus unlock biases and constrain interpretations of past life. Here we will use examples to illustrate how experiments can be applied to address a wide range of palaeobiological aims, from the understanding the origin of vertebrates, interpretations of fossil colour, and new data on the succession of microbial communities responsible for decay. This allows us to demonstrate the specific practicalities of experimental design and experimental variables in the context of decay, be those

biological, chemical, or physical, and furthermore, how experimental data can, and cannot, be applied to fossil data and evolutionary hypotheses. A rich array of possibilities for experimental investigations of fossilisation exist; the methodologies outlined aim here to provide guidance and conceptual framework for future studies.

A14.16 STRAIGHT TOES AND CURVY FOOTPRINTS: HOW TRACK MORPHOLOGY CAN DEFORM DURING FORMATION TO DISTORT FOOT ANATOMY

Friday 7 July 2023 09:00

p.l.falkingham@ljmu.ac.uk

We investigated how curved toe impressions in small bird and theropod dinosaur tracks can reveal foot movement patterns, rather than foot morphology. Small extant bird and fossil theropod dinosaur tracks can sometimes exhibit curved outer toe impressions (digits II and IV) that may bend either towards or away from the central digit impression (Digit III). However, as has been previously demonstrated, “footprints are not feet” and track morphology is the result of a complex footsediment interaction. In particularly soft substrates this interaction involves flow and reorganisation of sediment around the moving foot. We experimentally show using Guineafowl that these curved digit impressions can be the result of straight toed feet indenting a soft substrate. Rather than a record of anatomy, the curvature of these toe impressions might elucidate the way in which the foot that made them was moving, and thus be indicative of particular locomotor patterns. To explore this we used the discrete element method to simulate track formation. Using basic tridactyl feet comprised of four cylinders (three toes and a metatarsus), we generated virtual tracks in a range of abstracted scenarios including toes held at different angles (II-IV interdigital angles of 45 degrees and 90 degrees), toes closing or spreading during indentation, and movement of the foot from vertical, to indenting with forward or backward motions. We demonstrate that curved digit impressions in tracks arise from the flow of sediment around the toes, and the degree of curvature is primarily determined by the functional size of the hypex.

A14.17 THE CHALLENGE OF EXTRACTING BIOMECHANICAL DATA FROM FOOTPRINTS

Friday 7 July 2023 09:00

James Gardiner (Manchester Metropolitan University, United Kingdom), Barbara Grant (The University of Liverpool, United Kingdom), Kris D'Aout (The University of Liverpool, United Kingdom), James Charles (The University of Liverpool, United Kingdom), Peter Falkingham (Liverpool John Moores University, United Kingdom), Karl Bates (The University of Liverpool, United Kingdom)

james.gardiner@mmu.ac.uk

Fossil footprints offer us one of the few insights into how extinct animals moved. As such they have allowed us to investigate a broad range of topics such as the origins of hominid bipedalism, the locomotor performance of dinosaurs, and even potential predatorprey interactions between extinct species. However, extracting biomechanical data from fossil footprints is very challenging. Both their formation and subsequent preservation is influenced by numerous factors such a substrate type, moisture content, and deformation during fossilisation. Here, we present data from an experimental setup using sand filled walkways to generate footprints under controlled conditions. Human participants crossed the walkways under a variety of experimental conditions such as no-load vs load carrying, wet vs dry sand, and different sand types. The footprints created were then digitised using photogrammetry before further processing and analysis in Matlab. Each print was separated out from its trackway, a local ground level set and converted into a grid format analogous to pressure plate/insole data. Several analysis techniques were then tested on the footprints to look for differences between the experimental conditions. These techniques included pedobarographic statistical parametric mapping (pSPM), anatomical landmarking and basic foot subsection (heel/forefoot etc) depth measurements. All techniques found significant differences for factors causing large scale shape change such as sand moisture content (wet vs dry) but struggled to find differences for factors producing more subtle changes. The pros and cons of each analysis technique are discussed as well as which experimental factors were detectable in the footprints.

A14.18 AN ATTEMPT TO RECONSTRUCT ANCIENT PRIMATE MORPHOTYPES AND WHAT WE CAN LEARN ON PRIMATE LOCOMOTOR EVOLUTION

Friday 7 July 2023 09:30

François Druelle (CNRS, France), Gilles Berillon (CNRS, France), Mélanie Berthet (Parc Zoologique du Muséum de Besançon, France), Tasuku Kimura (The University Museum of Tokyo, Japan), Benoît Quintard (Parc Zoologique et Botanique de Mulhouse, France)

francois.druelle@mnhn.fr

The morphotypes (mass and length distributions) of extant primates, including humans, are diverse and reflect locomotor adaptations. Reconstructing the evolutionary history of primates requires to understand their locomotor evolution. However, the morphotypes of extinct primates are generally very partially reconstructed from fossil material. Their fragmentary nature generally impedes the application of quantitative methods which would require at least the whole skeletal body to attempt to reconstruct the segmental inertial properties. In this context, we have developed a methodological process that estimates theoretical ancestral morphotypes and their diversity at key periods of the primate phylogenetic tree. We have been collecting morphometrics via external measurements on anaesthetized primates (46 measurements/individual) in different centres for the last 5 years (e.g., zoological park of Besançon, zoological and botanical park of Mulhouse). We used a proven geometric model (Crompton et al., 1996) to reconstruct the morphotype of the measured individuals (n=132). The dataset collected represents the "morphospace" of extant primates as it includes extreme species (e.g., gibbons and humans) and intermediate species (bonobos, baboons, colobus) and thus covers an important morphological variation. By using phylogeny and a bootstrap method, we propose 1000 reconstructions per ancestral species (at the nodes of the phylogenetic tree). Comparisons of these

Peter L Falkingham (Liverpool John Moores University, United Kingdom), Stephen M. Gatesy (Brown University, United States)

possible extinct morphotypes to the proportions of some fossil taxa (e.g.,Ardipithecus ramidus, Sahelanthropus tchadensis) allows testing these reconstructions. Furthermore, locomotor adaptations can then be suggested for the reconstructed morphotypes, thus offering possible evolutionary scenarios for the process of bipedalisation, as well as for other locomotor adaptations (e.g., brachiation).

A14.19 THE EFFECT OF LOWER LIMB PROPORTIONS ON COST OF TRANSPORT OF WALKING AND RUNNING

Friday 7 July 2023 09:45

Evie E Vereecke (KU Leuven, Belgium), Tara Chapman (University Libre de Bruxelles, Belgium), Arthur Van der Have (KU Leuven, Belgium), Friedl De Groote (KU Leuven, Belgium)

evie.vereecke@kuleuven.be

Across the modern human population, the crural index (CI) – ratio of tibia to femur length - varies considerably, from 78 to 91. However, its mean value of 85 deviates from that of recent Homo species, with an average CI of 78 reported for H. neanderthalensis and estimates of 88 for H. erectus.While this variation is recognised, the impact of lower limb proportions on the energetics of walking and running remains unclear.

In this study, we use musculoskeletal modelling to evaluate the effect of lower limb proportions on biomechanical parameters of level, uphill and downhill walking (1.3m/s) and running (2.2m/s and 3.3m/s). Simulations were based on a generic whole body musculoskeletal model. Tibia and femur were scaled to obtain five different CI conditions (75, 80, 85, 90, 95) while keeping lower limb length constant. Gait simulations were generated by minimizing a movement-related cost while imposing speed and symmetry without relying on experimental kinematics.

Our simulations predicted that the cost of transport (COT) for level walking and running was insensitive to CI. Yet, muscle maximal activity, which is related to fatigue, did differ. For uphill and downhill walking larger COT differences were found between conditions, with the highest COT for CI 95 and CI 75-80 for uphill and downhill, respectively.

Physics-based simulations offer excellent opportunities to disentangle the effect of different parameters on gait mechanics and energetics. They are a great tool to achieve a better understanding of the impact of isolated features on locomotion, both in modern and extinct populations.

A14.20 AN EXPERIMENTAL ANALYSIS TO EVALUATE WALKING GAITS IN EXTINCT SOUTH AMERICAN UNGULATES

Friday 7 July 2023 10:00

Verónica Krapovickas (CONICET, Argentina), Rocio Belen Vera (CONICET, Argentina), Lucas Fernandez Piana (Universidad de San Andrés, Argentina), Martin E. Farina (CONICET, Argentina), Claudia A. Marsicano (CONICET, Argentina), Alicia De la Colina (Fundación Temaikén, Argentina), Anne D. Koelewijn (Friedrich-Alexander-Universität, Germany)

veronicakrapovickas@gmail.com

Macraucheniids, robust quadrupedal ungulates with elongated necks and long limbs with three- toed autopodia, are the more diverse and frequently found group in Neogene successions in southern South America. Their body plan is commonly compared to modern camelids. It has also been proposed they used symmetric walking gaits, like modern camelids. Exceptional macraucheniid trackways were found in Neogene successions in Argentina and can therefore be used as direct evidence for macraucheniid gaits. To evaluate the macraucheniid trackways and their putative gait, we used guanacos (Lama guanacoe) as the ungulate alive with the most similar body plan, because macraucheniids have no living representatives´ descendants. Eight female guanacos were trained to walk over a humid fine-grained sandy substrate at Temaikén Biopark (Buenos Aires, Argentina). Once a week from August to November 2021 (10 times), we filmed their gait in slow motion using a lateral and a dorsal camera, while we also recorded their trackways via photogrammetry. We recorded 44 laps that were suitable and classified these as walking or trotting. We compared trackway patterns of guanacos and macraucheniids visually using a newly proposed methodology based on linear transformations and numerically using the mean and variance of the distances between two consecutive foot impressions. We found that the mean and variance of symmetric walking gaits are smaller than those of trotting and that macraucheniids footprint patterns are nested within the guanaco's symmetric walking gaits, which further supports that macraucheniids walked symmetrically.

A14.21 CREATING NEW MUSCULOSKELETAL MODELS VIA GEOMETRIC MORPHOMETRIC TRANSFORMATION: FIRST STEPS TOWARDS PROJECTING MODELS ONTO FOSSIL SKELETAL DATA

Friday 7 July 2023

11:00

Julia Van Beesel (KU Leuven, Belgium), Adam Kewley (TU Delft, Netherlands), Philipp Gunz (Max Planck Institute for evolutionary Anthropology, Germany), Ajay Seth (TU Delft, Netherlands)

julia.vanbeesel@kuleuven.be

Musculoskeletal models (MMs) are useful tools for studying the relationship between anatomy and biomechanics, and are increasingly being used in investigations of fossils. However, creating new MMs is a time-consuming process that involves collecting musculoskeletal data that is impossible to obtain from fossils. Our objective was to develop a new workflow that would enable the creation of specimenspecific MMs using only skeletal input data, thereby reducing the time and effort required.

Our workflow involves transforming an existing MM to the subject-specific skeletal anatomy data. We test this approach by transforming an existing human shoulder MM to the skeletal data provided by the visible human project (VHP). We use the thin-platespline interpolation based on anatomical landmarks and sliding semilandmarks on curves and surfaces to warp muscle geometry. We evaluated the accuracy of the resulting model by comparing it to muscle geometry data obtained from VHP Cryo scans, as well as to a shoulder MM created using traditional methods and an MM adjusted using OpenSim's standard scaling tool.

Overall, the transformed MM closely resembled the specimenspecific musculoskeletal geometry and the MM created using traditional methods. We found that transforming an existing MM has

greater potential for representing specimen-specific biomechanical capabilities than scaling an MM. As a next step, we plan to explore the use of this workflow for transforming MMs between species, with the ultimate goal of applying this approach to the study of fossils.

ANCESTRAL HORSES.

Friday 7 July 2023 11:00

Jamie A MacLaren (Universiteit Antwerpen, Belgium), João P Oliveira de Almeida (Universiteit Antwerpen, Belgium), Kwinten Vangeel (Universiteit Antwerpen, Belgium), Sandra Nauwelaerts (Universiteit Antwerpen, Belgium)

amie.maclaren@uantwerpen.be

The tapir forelimb condition (tetradactyly) is also exhibited in the earliest ancestors of all other perissodactyl groups (including equids, rhinoceroses, brontotheres etc.), and is a stark contrast to the limbs of living families of perissodactyls (monodactyl equids and tridactyl rhinoceroses). The application and distribution of loading forces across the four digits of the manus remains integral to understanding how force application varied within the tetradactyl manus of basal perissodactyls, and how that may have influenced digit reduction in the ancestors of modern species. In this study, we examined under-foot pressure distribution in all modern tetradactyl perissodactyl species (Tapirus spp.), investigating load distributions and centre-of-pressure, and testing them against stress patterns (using FEA of metapodials modelled at mid-stance) and linear morphometric measurements in an effort to correlate pressure beneath each toe with mechanical / morphological characteristics of the manus. Our results suggest that mean pressure distributions per species are strongly correlated with metapodial length and midshaft depth, in addition to mean equivalent stress from FEA; however, this pattern does not hold true for all species. Interestingly, the centre-of-pressure for the modern Malayan tapir does not support biomechanical mesaxonic symmetry in this species (when walking). Extrapolating to the fossil record, equivalent stress of metapodials, digit lengths, and midshaft depths would all represent viable predictors for under-foot pressure in the earliest ancestors of modern horses, although care must be taken if inferring centre-of-pressure.

A14.23

Friday 7 July 2023 11:30

Ashleigh L A Wiseman (University of Cambridge, United Kingdom), Julia Van Beesel (Department of Development and Regeneration KU Leuven Campus Kulak Kortrijk Belgium., Belgium), Marta Mirazon Lahr (Department of Archaeology University of Cambridge Cambridge UK., United Kingdom), James Charles (Institute of Life Course and Medical Sciences University of Liverpool Liverpool UK., United Kingdom), John R Hutchinson (Structure and Motion Laboratory Department of Comparative Biomedical Sciences The Royal Veterinar, United Kingdom)

alw96@cam.ac.uk

In recent years, progresses in imaging and musculoskeletal modelling have greatly advanced how we can study the movement capacities of an extinct species. This talk will provide an overview of the challenges we face in evolutionary biomechanics, from discovery to simulation. To develop a musculoskeletal model, a scientist must first create a representation of the specimen’s skeleton, which might be heavily distorted and fragmentary. This can require extensive reconstruction and retrodeformation, and also rearticulation of disarticulated remains. After reassembling the skeleton, muscles must be added to the model. Soft tissues do not preserve in the fossil record, and thus assumptions must be made using a phylogenetic bracket of living, comparative species. However, the muscles’ shapes, sizes and configurations are not sufficient to drive the model forward. Rather, the muscles require estimation of their architectural data, such as fibre lengths and physiological cross-sectional areas, which do not preserve in the fossil record. The finalised model can be used to investigate movement through simulations of performance. The kinematics and kinetics of a specimen can be computed and biomechanical information such as moment arms, moments and muscle activations can be extracted so that we can model how an extinct species might have moved. Here, we present pelvic and lower limb musculoskeletal models of extinct hominin species, ranging from Australopithecus afarensis to Homo erectus, in which soft tissues were reconstructed, muscular parameters were estimated and preliminary simulations have begun to unravel changes in the movement capability within the human evolutionary lineage.

A14.24 MUSCULOSKELETAL MODELLING UNTANGLES THE ORIGINS OF MAMMAL FORELIMB FUNCTION AND POSTURE

Friday 7 July 2023 11:45

Robert J Brocklehurst (Harvard University, United States), Stephanie E Pierce (Harvard University, United States) rbrocklehurst@fas.harvard.edu

The ‘sprawling-parasagittal’ transition was a major postural shift in the ancestors of mammals, resulting in musculoskeletal reorganization of the forelimbs that underpins modern mammal locomotor diversity. However, ‘when’ and ‘how’ this important postural shift occurred is unknown. While the anatomical changes characterizing this transition can be traced through the fossil record, how these relate to functional changes, and the acquisition of parasagittal posture, remains poorly understood. We produced three-dimensional musculoskeletal models of the forelimbs of extant (n=3) and fossil (n=8) taxa that phylogenetically and functionally span the sprawling–parasagittal transition. We calculated joint range of motion (ROM) to determine a 3D pose-space, using the novel APSE algorithm (Accelerated Pose Searching with Electrostatics). We then estimated muscle moment

A14.22 TAPIRS PRESENT THE KEY TO HORSES PAST? INVESTINGATING TAPIR MANUS LOADING, WITH IMPLICATIONS FOR LOCOMOTION IN

FROM DISCOVERY TO SIMULATION: THE CHALLENGES OF MUSCULOSKELETAL MODELLING IN FOSSIL SPECIMENS

arms (MMAs) across the entire pose space for all muscles crossing the shoulder and elbow joints. Models of extant species were validated against empirical measures of ROM and MMA derived from ex vivo XROMM (X-ray reconstruction of moving morphology). Among extant species, in both models and experiments, our parasagittal taxon occupied a distinct region of pose-space, with more retracted and depressed shoulder joint angles. MMA data show increased emphasis on shoulder elevation associated with a parasagittal posture, but greater shoulder depression in sprawlers. We hypothesised the fossil taxa would follow trends in these postural variables – e.g., increasing shoulder retraction and elevation MMAs through time –but they instead showed complex, non-linear patterns of forelimb transformation. We demonstrate that the ‘sprawling-parasagittal’ transition is characterized by considerable homoplasy and continuous postural variation throughout mammalian evolution.

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A14.25 RESURRECTING THE PAST: USING DATA FROM LIVING ANIMALS AND BIOMECHANICAL SIMULATIONS TO UNDERSTAND FEEDING, FORM AND FUNCTION IN FOSSILS.

Friday 7 July 2023 12:0 0

Emily J Rayfield (University of Bristol, United Kingdom)

e.rayfield@bristol.ac.u

The discovery and description of fossil animals frequently precludes questions such as, how did this animal live, how did it function? A challenge for palaeobiologists is, therefore, if and how we can address these queries within a scientific framework. Functional morphology has advanced from Gould’s famous ‘Just-so stories’, through to the first introduction of rigours such as Rudwick’s paradigm approach, and the conceptual framework of Seilacher that recognised the influence of adaptation, but also phylogeny, development and other environmental and material constraints on the evolution of form and function. Today, palaeobiologists have a range of tools available to interrogate the function and evolution of organisms and ‘bring fossils back to life’. In this invited talk I will discuss two fruitful approaches: (1) the integration of biological and palaeobiological data, particularly as applied to study of the origin of tetrapods and the origin of mammals; and, (2) the application of physical principles to define and test biomechanical hypotheses in palaeobiological analysis. Both approaches hold much promise, but have limitations. Biological data can be difficult to obtain and may require expensive data capture equipment. Conversely, barriers such as software cost and access have diminished over recent years, promising equity and inclusivity within palaeobiomechanics, yet the application of physical principles requires careful application of hypotheses and an understanding of the utility and drawbacks of the model systems employed.

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CELL BIOLOGY ABSTRACTS

C1 - LOCAL AND HIGHER ORDER NUCLEAR STRUCTURAL ORGANIZATION AND DYNAMICS

ORGANISED BY: ERIC SCHIRMER (UNIVERSITY OF EDINBURGH, ALINE PROBST (INSTITUTE OF GENETICS, REPRODUCTION AND DEVELOPMENT)

C1.1 THE STRUCTURAL ORGANIZATION AND FUNCTIONS OF THE NUCLEAR LAMINS

Tuesday 4 July 2023 09:00

Robert D. Goldman (Northwestern University, United States)

r-goldman@northwestern.edu

Studies of the nucleoskeletal Type V intermediate filaments (IFs), the nuclear lamins, reveal their roles in integrating a wide range of physiological functions in mesenchymal cells. Within the nucleus, lamins A, C, B1 and B2 assemble into distinct interwoven filamentous meshworks. These meshworks are interspersed with nuclear pore complexes to form the major structures of the nuclear lamina (NL) connecting the inner nuclear envelope membrane to chromatin. Our recent data show that the lamin meshworks are connected to a juxtanuclear cage of VIFs by linker of nucleoskeleton and cytoskeleton (LINC) complexes spanning the inner and outer nuclear envelope membranes. The cage of VIFs is continuous with an extensive cytoskeletal network which interacts with the F-actin rich cell cortex. Using a combination of microscopic, microrheological and micromechanical techniques we and our collaborators demonstrate that the lamins, through their interactions with VIFs, function in regulating nuclear size, shape, chromatin organization and mechanical properties. Evidence will also be presented that the lamin/cytoskeletal VIF networks are involved in regulating cell size, the stiffness of the cell surface, cell contractility, adhesion and motility. The interactions between nucleoskeletal and cytoskeletal networks of IFs provide cells with a global response system capable of reacting to and transmitting mechanical and chemical stimuli. This work is supported by a Program Project funded by the NIH General Medical Sciences Institute and the 4D Nucleome Project of the NIH Common Fund.

C1.2 DIVERSITY IN NUCLEAR ORGANISATION AND MRNA PROCESSING

Tuesday 4 July 2023 10:00

Mark C Field (University of Dundee, United Kingdom)

mfield@mac.com

The spacio-temporal regulation of chromatin is well understood as an important aspect of securing gene development programs; this is no less the case for unicellular protists than multicellular plants, animals or fungi. However, it is also clear that the molecular mechanisms employed can exhibit considerable divergence. While remaining incomplete, from studies in protists it is emerging that an amalgam of conserved and divergent systems operate together to coordinate nuclear organisation. I will discuss our own work in trypanosomes, that has uncovered novel mechanisms involving completely divergent machinery, repurposing of conserved components and the modification of macromolecular machinery to facilitate a distinct mode of nuclear organisation.

C1.3 SEB AND NUCLEAR STRUCTURE AND DYNAMICS RESEARCH

Tuesday 4 July 2023 13:30

David E Evans (Oxford Brookes University, United Kingdom) deevans@brookes.ac.uk

This talk will contribute to the Society's centenary year by describing advances made over the last 25 years in understanding the structure and dynamics of the cell nucleus. Special attention will be given to the contribution of SEB symposia and conference sessions and to the work of the community of SEB members in this area. The talk will also look to the future - both in terms of scientific goals and in the development of the careers of young scientists, including the importance of the Society's awards and medals.

C1.4 REDISCOVERING THE CHROMONEMA

Tuesday 4 July 2023

14:00

Amanda S Câmara (Institute of Plant Genetics and Crop Plant Research, Germany)

camara@ipk-gatersleben.de

The definition of the chromonema dates back to the first observations of chromosomes under compound microscopes in the late 19th century. It is a coiled thread of chromatin that compacts chromosomes into little rods. This model of compaction, based solely on light microscopy, endured for several decades and strengthened from the struture

of the DNA double helix, when it seemed reasonable that the DNA would further coil to a more compact structure. But it later received several disbelieves as the old observations seemed to be an artefact of shearing, and the coiling mechanism too elaborate to encompass several length scales. It also disregarded other structural components as topoisomerases and condensin protein complexes, which became as evident as chromatin loops in the organization of chromosomes. Renewing the interest, chromosome conformation capture sequencing (Hi-C) clearly indicated a helical organization of mitotic chromosomes. With polymer simulation, a bottle-brush model was suggested, in which chromatin loops branch out from a helical protein scaffold. After reviewing Hi-C data from mitotic chromosomes of different species and polymer models of loop extrusion and considering the lack of a continuous protein scaffold (as yet unobserved), we propose a refurbished definition of the chromonema as an entity formed by chromatin loops and rather plastic. We hypothesize that a self-coiling mechanism, depending on the properties of the chromonema, can be general to many eukaryotic species, while accounting for their dissimilarities. Our hypothesis relies on entropic effects already known to guide chromosome organization, but further evidence still needs to be collected.

C1.5 THE NUCLEAR ENVELOPE AND CALCIUM SIGNALLING IN DICTYOSTELIUM DISCOIDEUM

Tuesday 4 July 2023 14:15

Chenli Wu (University of Edinburgh, United Kingdom),

Z Ding (University of Edinburgh, United Kingdom),

E C Schirmer (University of Edinburgh, United Kingdom),

T Theil (University of Edinburgh, United Kingdom),

A M Evans (University of Edinburgh, United Kingdom),

S K Maciver (University of Edinburgh, United Kingdom)

C.Wu-52@sms.ed.ac.uk

We are developing tools to useDictyostelium discoideum,a genetically tractable model organism to investigate calcium signalling in the eukaryotic nuclear envelope (NE). We have used GFP-SUN1 and GFPNup210 fusion protein constructs to delineate the NE and as expected find that the NE is continuous with the endoplasmic reticulum stained with ER tracker™ dye. Meanwhile, we see that the ER appears to extend across the NE into the nucleus. Therefore, we used the GFPCalnexin A fusion protein construct, which delineate the ER to further confirming that. However, using ER tracker and various fluorescent calcium signalling dyes such as Calcium Orange™, AM and Fluo-4, AM produced inconsistent staining patterns in the cells. We concluded that the dyes were not able to penetrate healthyDictyosteliumcells equally. We investigated the effect of temperature on staining/penetration of cells at 20, 25 and 30℃ but found little difference. To get around this problem of penetration, we have investigated the use of the antibiotic polymyxin B to destabilize the plasma membrane to allow calcium and other fluorescent stains into healthyDictyosteliumcells. Using fluorescent dextran as a marker we found that polymyxin B allowed dextran into healthy cells.

C1.6 DO NUCLEAR ENVELOPE INVAGINATION NETWORKS DIRECT CALCIUM FLUX TO MODULATE EXPRESSION OF GENES LINING THE INVAGINATIONS?

Tuesday 4 July 2023 14:30

Qingqin Ji (The University of Edinburgh, United Kingdom), A. Mark Evans (The University of Edinburgh, United Kingdom), Eric Schirmer (The University of Edinburgh, United Kingdom)

qingqin.ji@ed.ac.uk

The nuclear envelope (NE) separates the nucleus from the cytoplasm, it also contributes to numerous cellular processes such as genome organization, transcription regulation, and signalling. Though typically thought of as spherical or ovoid, the NE in some cell types such as pulmonary arterial smooth muscle cells (PASMCs) is neither, but is interrupted with branches reaching deep into the nucleoplasm or even completely traversing the nucleus, known as NE invaginations (NEIs). Although NEIs functions are not fully understood, there is evidence that they can hold and flux calcium stores between cytoplasmic pockets formed by NEIs and the adjacent nuclear envelope lumen. My hypothesis is that this calcium flux can induce genes release from the nuclear envelope to support their activation.

The first step to test this hypothesis is to identify genes lining NEIs. While there are no proteins uniquely lining NEIs, there are several proteins with different nuclear distribution patterns such that comparing sets of genes interacting with different proteins should yield intersect subsets unique to NEIs. Immunostaining for nuclear envelope proteins and epigenetic marks revealed lamin A, emerin, nesprin, SUN2, BAF, and H3K9me2 lining various NEIs. While each had other nuclear localizations, other chromatin and nuclear envelope proteins were absent from NEIs that can be used to generate subtractive intersect subsets. I will identify the NEI-associated genes by CUT&RUN-sequencing and comparing the datasets of these different protein groups and then test individual genes by fluorescence in-situ hybridization (FISH) upon drug treatments promoting calcium release from NEI stores.

C1.7 EVOLUTIONARY CONSERVED PROTEIN MOTIFS DRIVE INTERACTIONS BETWEEN THE PLANT NUCLEAR LAMINA AND NUCLEAR PORES

Tuesday 4 July 2023 14:45

Christophe Tatout (Université Clermont Auvergne, France), Sarah MERMET (Université Clermont Auvergne, France), Sylvie TUTOIS (Université Clermont Auvergne, France), Kentaro TAMURA (University of Shizuoka, Japan), Emmanuel VANROBAYS (Université Clermont Auvergne, France)

christophe.tatout@uca.fr

Increasing evidence suggest that the nuclear envelope, nuclear pores and the nuclear lamina are closely connected to perform their function in a coordinated manner, but these interactions remain poorly understood in particular in plants. Here we have chosen to investigate the protein network at the plant nuclear periphery in Arabidopsis

thaliana using the nuclear lamina protein KAKU4 as an entry point. KAKU4 is a plant specific protein, enriched at the nuclear periphery where it interacts with CRWN proteins, the main components of the plant lamina. We discovered that KAKU4 contains short peptide motifs shared with NUP82 and NUP136, two components of the nuclear pore complex (NPC) basket. We further show that, in yeast and in planta, the short peptide motifs in KAKU4, NUP82 and NUP136 mediate proteinprotein interactions with the CRWN proteins supporting the existence of a continuum between the nuclear lamina and the nuclear pores. Genetic interactions support an additive role of KAKU4 and NUP136 during plant development. Finally, evolutionary analyses suggest a scenario of functional diversification of KAKU4 from an ancestral nucleoporin to a component of the nuclear lamina.

C1.8 EXPLOITING DIVERGENT BIOLOGY OF TWO FISSION YEASTS TO UNDERSTAND MEMBRANE FUNCTION

Tuesday 4 July 2023 15:30

Snezhana Oliferenko (King's College London and the Francis Crick Institute, United Kingdom)

snezhana.oliferenko@kcl.ac.uk

Biological membranes are semi-permeable lipid barriers delimiting cells and subcellular compartments. By recruiting and scaffolding specific proteins and protein complexes, membranes also serve as platforms for cellular communication, signalling and metabolism. The specific features of the membrane depend on its lipid composition. I will present our recent work aimed at understanding how lipid metabolism impacts on membrane function and cellular physiology using comparative and synthetic approaches in two related fission yeast species with different lifestyles. Briefly, we show that a popular model systemSchizosaccharomyces pombeand its less known relativeSchizosaccharomyces japonicusexhibit strikingly different membrane lipid composition and provide the mechanistic explanation for this divergence. I will further argue that these differences in lipid metabolism may be at root of the profound changes to cellular physiology that occurred in the evolution of the fission yeast clade.

C1.9 MOLECULAR DISSECTION OF THE NE-ER INTERFACE IN PLANTS USING HIGH RESOLUTION IMAGING

Tuesday 4 July 2023 16:00

Nadine Field (Oxford Brookes University, United Kingdom), Charlotte Pain (Oxford Brookes University, United Kingdom), David Evans (Oxford Brookes University, United Kingdom), Verena Kriechbaumer (Oxford Brookes University, United Kingdom), Katja Graumann (Oxford Brookes University, United Kingdom)

19180311@brookes.ac.uk

The endoplasmic reticulum (ER) is a large and dynamic organelle present in all eukaryotes, with functions including the synthesis, transport and folding of proteins. The ER spans the entire cell, with the peripheral ER spread throughout the cytoplasm and the perinuclear ER surrounding the nucleus. The nucleus itself is surrounded by a

double-membrane structure called the nuclear envelope (NE) which is continuous with the ER but functionally and structurally distinct. Formation and maintenance of this NE-ER ‘interface’ in plants are not well understood but in other eukaryotic systems, a role for ER morphogens is starting to crystalize, including Lunapark and reticulon proteins. In plants, reticulon proteins induce curvature of peripheral ER membranes, forming structures called tubules. Antagonistically, Lunapark proteins induce the formation of flat sheets of membrane. However, in yeast, these proteins are associated with additional structural changes at this interface; for example,S cerevisiaeLunapark 1 and Reticulon 1 double knockouts exhibit defective nuclear pore complex positioning. Whether these proteins perform parallel functions in plants is unknown. In this project we are investigating the function of ER morphogens such as Lunapark and reticulons in the NE-ER interface. Using electron microscopy, we show overexpression of Lunapark 1 leads to NE blebbing in Arabidopsis roots. Furthermore, through high-resolution confocal live-cell microscopy, overexpression of Lunapark 1 in tobacco was shown to induce dynamic changes in the perinuclear ER including reducing sheet and tubule speed. This provides first evidence of a functional role for ER morphogens in regulating the NE-ER interface in plants.

C1.10 RAPID CYCLES OF SATELLITE HOMOGENIZATION AND RETROTRANSPOSON INVASION DRIVE ARABIDOPSIS CENTROMERE EVOLUTION

Tuesday 4 July 2023 16:15

Ian R Henderson (University of Cambridge, United Kingdom)

irh25@cam.ac.uk

Centromeres are critical for cell division, loading CENH3/CENPA histone variant nucleosomes, directing kinetochore formation and allowing chromosome segregation . Despite their conserved function, centromere size and structure are diverse across species. To understand this centromere paradox , it is necessary to know how centromeric diversity is generated, and whether it reflects ancient trans-species variation or, instead, rapid post-speciation divergence. To address these questions, we assembled 346 centromeres from 66 Arabidopsis thaliana and two A. lyrata accessions, which revealed a remarkable degree of intra- and inter-species diversity. Arabidopsis thaliana centromere repeat arrays are embedded in linkage blocks, despite ongoing internal satellite turnover, demonstrating a role for unidirectional gene conversion in sequence diversification, rather than interhomolog unequal crossover. Additionally, centrophilic ATHILA transposons have recently invaded the satellite arrays. To counter ATHILA invasion, chromosome-specific bursts of satellite homogenization generate higher-order repeats and purge transposons, consistent with cycles of repeat evolution. Centromeric sequence changes are even more extreme in comparison between A. thaliana and A. lyrata. Together, our findings reveal rapid cycles of transposon invasion and purging via satellite homogenization, which drive centromere evolution and ultimately contribute to speciation.

C1.11 THE RELATIONSHIP BETWEEN 3D GENOME STRUCTURE AND GENE REGULATION DRIVES BRAIN CELL FUNCTIONS

Wednesday 5 July 2023 09:00

Ana Pombo (Berlin Institute for Medical Systems Biology Max Delbrück Centre for Molecular Medicine Berlin, Germany)

Ana.Pombo@mdc-berlin.de

The three-dimensional (3D) structure of chromosomes is associated with gene regulation and cell function. Our recent work applies Genome Architecture Mapping (GAM) to explore 3D genome structure variation in highly specialised brain cells. We study how genetic variation associated with disease or environmental stimuli interferes with 3D genome structures, and present advances in mapping parental-specific differences in 3D chromosome structures.

C1.12 UNIQUE ACTIVITIES OF TWO OVERLAPPING PAX6 RETINAL ENHANCERS

Wednesday 5 July 2023 09:30

Kirsty Uttley (MRC Human Genetics Unit The University of Edinburgh, United Kingdom), Andrew S Papanastasiou (MRC Human Genetics Unit The University of Edinburgh, United Kingdom), Manuela Lahne (UCL Institute of Ophthalmology, United Kingdom), Jennifer M Brisbane (MRC Human Genetics Unit The University of Edinburgh, United Kingdom), Ryan B MacDonald (UCL Institute of Ophthalmology, United Kingdom), Wendy A Bickmore (MRC Human Genetics Unit The University of Edinburgh, United Kingdom), Shipra Bhatia (MRC Human Genetics Unit The University of Edinburgh, United Kingdom)

kirsty.f.uttley@gmail.com

Enhancers play a critical role in development by precisely modulating spatial, temporal, and cell type-specific gene expression. Sequence variants in enhancers have been implicated in disease, however establishing the functional consequences of these variants is challenging due to a lack of understanding of precise cell types and developmental stages where the enhancers are normally active. PAX6 is the master regulator of eye development, and has a regulatory landscape containing multiple enhancers driving expression in the eye. Whether these enhancers perform additive, redundant, or distinct functions is unknown. Here we describe the precise cell types and regulatory activity of two PAX6 retinal enhancers, HS5 and NRE. Using a unique combination of live imaging and single-cell RNA sequencing in dual enhancer-reporter zebrafish embryos, we find significant differences in the spatiotemporal activity of these enhancers, and show that HS5 and NRE are active in distinct cell types of the developing retina. Our results show that although overlapping, these enhancers have distinct activities in different cell types and therefore likely nonredundant functions. This work demonstrates that unique cell typespecific activities can be uncovered for apparently similar enhancers when investigated at high resolution in vivo.

C1.13 NUCLEAR ENVELOPE TRANSMEMBRANE PROTEINS INVOLVED IN GENOME ORGANIZATION ARE MISREGULATED IN MYOTONIC DYSTROPHY TYPE 1 MUSCLE

Wednesday 5 July 2023 09:45

Peter Meinke (Friedrich-Baur-Institut LMU Munich, Germany), Vanessa Todorow (Friedrich-Baur-Institut LMU Munich, Germany), Stefan Hintze (Friedrich-Baur-Institut LMU Munich, Germany), Benedikt Schoser (Friedrich-BaurInstitut LMU Munich, Germany)

Peter.Meinke@med.uni-muenchen.de

Myotonic dystrophy type 1 is a multisystemic disorder with predominant muscle and neurological involvement. Despite a well described pathomechanism, which is primarily a global missplicing due to sequestration of RNA-binding proteins, there are still many unsolved questions. One such question is the disease etiology in the different affected tissues. We observed alterations at the nuclear envelope in primary muscle cell cultures before. This led us to reanalyze a published RNA-sequencing dataset of DM1 and control muscle biopsies regarding the misregulation of NE proteins. We could identify several muscle NE protein encoding genes to be misregulated depending on the severity of the muscle phenotype. Among these misregulated genes were NE transmembrane proteins (NETs) involved in nuclearcytoskeletal coupling as well as genome organization. For selected genes, we could confirm that observed gene-misregulation led to protein expression changes. Furthermore, we investigated if genes known to be under expression-regulation by genome organization NETs were also misregulated in DM1 biopsies, which revealed that misregulation of two NETs alone is likely responsible for differential expression of about 10% of all genes being differentially expressed in DM1. Notably, the majority of NETs identified here to be misregulated in DM1 muscle are mutated in Emery-Dreifuss muscular dystrophy or clinical similar muscular dystrophies, suggesting a broader similarity on the molecular level for muscular dystrophies than anticipated. This shows not only the importance of muscle NETs in muscle health and disease, but also highlights the importance of the NE in DM1 disease progression.

C1.14 THE PLANT NUCLEAR LAMINA DISASSEMBLES TO REGULATE THREEDIMENSIONAL GENOME FOLDING UNDER STRESS CONDITIONS

Wednesday 5 July 2023 10:00

Chang Liu (University of Hohenheim, Germany)

chang.liu@uni-hohenheim.de

The nuclear lamina is a complex network of nuclear lamins and laminassociated nuclear membrane proteins, which scaffold the nucleus to maintain structural integrity. In Arabidopsis thaliana, Nuclear Matrix Constituent Proteins (NMCPs) are essential components of the nuclear lamina and are required to maintain the structural integrity of the nucleus and specific perinuclear chromatin anchoring. At the nuclear periphery, suppressed chromatin overlapping with repetitive sequences and inactive protein-coding genes are enriched. At a chromosomal

level, plant chromatin organization in interphase nuclei is flexible and responds to various developmental cues and environmental stimuli. Based on these observations in Arabidopsis, and given the role of NMCP genes (CRWN1 and CRWN4) in organizing chromatin positioning at the nuclear periphery, one can expect considerable changes in chromatinnuclear lamina interactions when the global chromatin organization patterns are being altered in plants. Here, we report the highly flexible nature of the plant nuclear lamina, which disassembles under various stress conditions. Focusing on heat stress, we reveal that on a genomewide scale, chromatin that initially tethered to the nuclear envelope, remain largely associated with CRWN1 and become scattered in the inner nuclear space. Via investigating the three-dimensional chromatin contact network, we reveal that CRWN1 proteins play a structural role in shaping the changes in genome folding under heat stress. Also, CRWN1 acts as a negative transcriptional co-regulator to modulate the shift of the plant transcriptome profile in response to heat stress. Such function appears to be important to prevent plants from developing highly active ROS signaling and necrosis.

C1.15 DYNAMIC CHROMATIN DURING PLURIPOTENCY AND GASTRULATION

Wednesday 5 July 2023 11:00

Susan Mango (BiozentrumUniversity of Basel, Switzerland)

susan.mango@unibas.ch

The nucleus undergoes dramatic alterations during embryogenesis, from transcriptional quiescence at fertilization to pluripotency and ultimately to a heterogeneous, differentiated state with distinct patterns of gene expression and chromatin organization. Our work focuses on the gastrula embryo, when heterochromatin is established, dosage compensation is established and pluripotency is lost. We use Chromosome Tracing and other methods to examine DNA structure at the megabase scale and test their functions in the developing embryo.

C1.16 LIVE VISUALIZATION OF THE KLF4 LOCUS IN MOUSE EMBRYONIC STEM CELLS

Wednesday 5 July 2023 11:30

Jente Van Staalduinen (Jente van Staalduinen, Netherlands), Hélène Kabbech (Erasmus Medical Center, Netherlands), Ihor Smal (Erasmus Medical Center, Netherlands), Frank G Grosveld (Erasmus Medical Center, Netherlands)

j.vanstaalduinen@erasmusmc.nl

The transcriptional activation of many tissue-specific genes depends on the regulatory action of distal enhancer elements. Several functional studies have shown that spatial proximity is required for enhancerdependent transcription. However, how rapid cis-regulatory elements sample their 3D environment and which molecular processes play a role in shaping their dynamics remain largely unexplored. A recent study suggested that the relative mobility of enhancers and promoters is affected by transcriptional activity. In this project, we set out to test this hypothesis by studying the biophysical dynamics of the Klf4 locus. We use the ANCHOR3 DNA labelling system to visualize several locations within the Klf4 model locus, including the well-characterized Klf4

enhancer cluster, promoter and non cis-regulatory elements. We are in the process of single locus tracking these viewpoints and estimating their diffusion coefficients and anomalous scaling exponents in a transcriptionally active (mouse embryonic stem cells) and inactive cellular state (mouse epiblast-like stem cells). We anticipate that our experiments will provide further insights into the movement of mammalian genomic loci across space and time.

C1.17 ASSAYING THE 3D GENOME TO HIGH SPATIAL RESOLUTION IN RARE/ VALUABLE CELL SAMPLES, PRIMARY CELLS CONTAINING AN INTEGRATED HIV-1 VECTOR

Wednesday 5 July 2023 11:45

Alexander Ward (University College London, United Kingdom)

rekgaiw@ucl.ac.uk

The 3D conformation of cell genomes has functional influence on the rate of gene expression. Chromosomes in animal genomes are partitioned into broad regions of higher and lower transcriptional activity (A and B compartments). Within this high-level spatial segregation, the chromosome fibre is divided into hierarchical contact domains of increased chromatin interaction to the exclusion of neighbouring contact domains. Within these insulated search spaces enhancer-promotor contacts take place. Presented here, as a result of the optimisation and modification of the original high throughputchromosome conformation capture (HiC) protocol are rich contact matrices generated from as few as 50,000 primary human T cells. From these matrices, the bioinformatic annotation of the above-described features of the 3D genome are presented for samples taken at the resting and activation cell fate statuses of human CD4+ memory T cells. The dynamic changes in the organisation of the 3D genome are correlated to the expression level of host genes that have been identified as important targets of HIV-1 integrationin vivo. Progress towards the goal of identifying specific regions of the host genome that harbour transcriptionally silent, but re-activatable, HIV-1 will be outlined. These chromatin regions, and their specific combination of epigenetic marks, would in future become the therapeutic targets of next generation latency reversing agents. Removal of re-activatable proviruses from the reservoir would represent a functional cure for HIV-1 infection.

C1.18 NUCLEAR LAMINA PROTEIN PNET2 REGULATES GENE EXPRESSION THROUGH SEQUESTRATION OF A FAMILY OF MEMBRANE-BOUND TRANSCRIPTION FACTORS IN PLANTS

Wednesday 5 July 2023 12:00

Yu Tang (University of California Berkeley, United States)

yutang@berkeley.edu

Membrane-bound transcription factors are known to be released from membranes for gene regulation in response to external and internal stimuli. However, the regulation of this process at the level of nuclear

membrane proteins remains unclear. In this study, we identified that the nuclear lamina component PNET2 directly interacts with a family of NAC transmembrane motif1-like (NTL) transcription factors by yeast-two hybrid screening. Transient co-expression of PNET2 and NTL proteins in plants resulted in their colocalization at the membrane. Our results demonstrate that PNET2 associates with the anchors of the NTL family of proteins at the nuclear membrane and is a critical regulator of NTL activity. Dominant repressors of NTL proteins using chimeric repressor silencing technology partially suppress the dwarf phenotype of pnet2 mutants. Additionally, whole transcriptome analysis revealed that the expression of many transcription factors was significantly restricted by NTL repressors in pnet2 mutants. Taken together, our study provides evidence that PNET2 plays a critical role in regulating gene expression by associating with NTL family members at the nuclear membrane in plants.

C1.19 GENE REGULATORY INTERACTIONS AT LAMINAASSOCIATED DOMAINS

Wednesday 5 July 2023 12:15

Interactions of chromatin with the nuclear envelope via laminaassociated domains (LADs) confer structural stability to the genome and may contribute to lineage commitment. We show a dynamic repositioning of stand-alone LADs and of LAD borders during early adipocyte differentiation. Adipogenic genes are either already localised in inter-LADs in adipocyte progenitors, or are released from LADs after differentiation induction, while de novo LADs sequester non-adipose lineage-specific genes. LAD repositioning however only partly concurs with gene expression changes. We identify differentially expressed genes in LADs, which reside in local H3K9me3-depleted, euchromatic pockets of low lamin B1 or lamin A/C contact frequency. GeneHancer, ECHi-C, histone ChIP-seq and imaging data show that enhancers of expressed in-LAD genes are located (i) within these LAD active pockets, (ii) outside LADs, or (iii) in LADs but are released from the lamina to approach their in-LAD target genes. Our data further argue that A-type lamins restrain gene expression within in-LAD euchromatic pockets. At a higher-order chromatin organisation level, FISH analyses reveal that multiple LADs form clusters at the nuclear periphery, whereas inter-LAD domains adopt a looser configuration. Down-regulation of lamin A/C or B1 preserves LAD clusters and leads to aggregation of inter-LADs, both in a manner dependent on CBX5/HP1alpha. This suggests that chromatin tension, under influence of lamins and CBX5/ HP1alpha, spatially segregates LADs from inter-LADs. Our data argue that chromatin conformation, tension and epigenetic states functionally converge to regulate gene expression at the nuclear periphery.

Cells are subjected to mechanical deformations within tissue microenvironment resulting inaltered gene expression programs, although the underlying mechanisms are unclear. In this talk, Iwill first discuss the tight coupling between cell mechanics and cytoskeletal-nuclear architecture.I will then show that the deformation of cells results in activating specific nuclearmechanotransduction pathways and cytoskeletal-dependent chromosome reorganization. Furthermore, I will demonstrate that the mechanical state of cells, and thus their chromosomeorganization and their intermingling, dictate microenvironmental control of gene expressionprograms. These results highlight an important layer of genome regulation resulting from thecoupling between cell/nuclear mechanics and 3D organization of chromosomes to maintaintissue homeostasis.

C1.21 LAMIN B RECEPTOR (LBR)TELOMERE AXIS PROTECTS CELLS FROM CHROMOSOMAL INSTABILITY AND TUMORIGENESIS

Wednesday 5 July 2023 15:30

Kundan Sengupta (Indian Institute of Science Education and Research (IISER-Pune), India)

kunsen@iiserpune.ac.in

Lamin B Receptor (LBR) is an inner nuclear membrane protein required to re-assemble the nuclear envelope post mitosis. In addition to inducing mitotic and nuclear aberrations, LBR loss also shows chromosome-specific losses. Strikingly, chromosomes showing a higher frequency of losses were enriched within the micronucleus. Furthermore, LBR depletion increases tumorigenesis in mouse xenografts. Remarkably primary cells derived from these tumors also showed chromosomal instability. Interestingly LBR depletion also modulates chromatin organization, enhancing intermingling between translocating chromosome territories, potentially creating a unique chromatin configuration susceptible to chromosomal instability. Furthermore overexpression of LBR showed LBR degradation, revealing a stringent control over LBR levels. LBR loss showed an increase in Telomere Repeat-Binding factor 1 (TRF1) levels, the knockdown of which restored chromosomal stability. We also uncovered a novel sub-interactome of LBR by performing mass-spectrometry involving the nucleolar protein Fibrillarin (FBL), cytoskeletal protein γ-Tubulin, and the telomere protein - TRF2. In summary, a novel LBR-TRF axis protects cells from chromosomal losses maintaining chromosomal stability in diploid colorectal cancer cells.

ENVELOPE TRANSMEMBRANE PROTEIN MISREGULATION IN DM1

Wednesday 5 July 2023 15:45

Wednesday 5 July 2023 15:00

G.V.

shiva.gvs@gmail.com

C1.22 SINGLE-NUCLEI RNASEQUENCING OF MUSCLE BIOPSIES

Philippe Collas (University of Oslo, Norway) philippe.collas@medisin.uio.no

C1.20 NUCLEAR MECHANICS AND GENOME REGULATION

Shivashankar (ETH Zurich, Switzerland)

Vanessa Todorow (Friedrich-Baur-Institut LMU Munich, Germany), Shinichiro Hayashi (National Center of Neurology and Psychiatry, Japan), Stefan Hintze (Friedrich-Baur-Institut LMU Munich, Germany), Benedikt Schoser (Friedrich-BaurInstitut LMU Munich, Germany), Ichizo Nishino (National Center of Neurology and Psychiatry, Japan), Peter Meinke (Friedrich-Baur-Institut LMU Munich, Germany)

vanessa.todorow@med.uni-muenchen.de

Muscle-specific nuclear envelope transmembrane proteins (mNETs) are mis-regulated in myotonic dystrophy (DM1). Here I show the expression pattern of mNETs in different cell types as determined by single-nuclei RNA-sequencing of muscle biopsies from DM1 patients and controls. Mature muscle contains different myofiber types (slow and fast twitching) as well as several non-muscle cells that support muscle development, maintenance and regeneration. These cell types are differentially affected in DM1 patients with a predominance of slowtwitching myofibers. We showed before that LINC complex component SYNE1 is mis-regulated and mis-spliced in DM1. Its’ functions include mechano-transduction and nuclear migration and thus potentially contributes to the observed mis-regulation of signaling pathways und nuclear positioning in DM1. Using snRNAseq we can now unravel in which cell types SYNE1 and other mNETs are expressed.

POSTER SESSION

Wednesday 5 July 2023 17:15-19:15

C1.24 EPIGENETIC PRIMING: A KEY PLAYER IN FACILITATING PLANT ADAPTATION UNDER CHANGING ENVIRONMENTAL CONDITIONS

Wednesday 5 July 2023 POSTER SESSION

Irene Luzzi (University of Padova, Italy), Serena Varotto (University of Padova, Italy), Alessandra Ruggiero (Institute of Biosciences and Bioresources, Italy), Stefania Grillo (Institute of Biosciences and Bioresources, Italy), Giorgia Batelli (Institute of Biosciences and Bioresources, Italy)

irene.luzzi@phd.unipd.it

plants have evolved molecular mechanisms to cope with water scarcity. This requires an intricate network to regulate gene expression at transcriptional/post-transcriptional levels, including epigenetic switches. Epigenetic processes are crucial adaptive mechanisms which change the expression of genes in a heritable way without accompanying changes in DNA sequences. In eukaryotic cell, the structure/function of chromatin depends upon several regulatory epigenetic mechanisms, including DNA methylation and histone modifications. These modifications may provide a basis for a stress memory, enabling plants to respond more efficiently to recurring stress or to prepare their offspring for potential future assaults. To gain insights into chromatin dynamics and map histone modifications genome-wide in tomato, ChIP-seq will be employed to analyse wt plants and epiregulator mutants after stress application and recovery. For this purpose, we are analysing two histone modifications (H3K4me3

and H3K27me3) and the histone variant H2A.Z to unveil their role in changing chromatin states in response to stress and investigate their associations with changes in the transcriptome. By integrating RNAseq, ChIP-seq and genomic data, we will shed light on the correlation between transcriptome variation and variation in epigenetic states at specific genomic regions. Altogether, we aim to study the association between gene expression and different histone marks after stress and the removal of the stimulus to identify loci that show transcriptional/ chromatin memory.

C1.25 UBP5 CONTROLS PLANT DEVELOPMENT THROUGH THE REGULATION OF CHROMATIN DYNAMICS

Thursday 6 July 2023 09:00

Sara Farrona (University of Galway, Ireland), Godwin James (University of Galway, Ireland), Mohan Govindasamy (University of Galway, Ireland), Kiruba Nedounsejian (University of Galway, Ireland)

sara.farrona@universityofgalway.ie

UBIQUITIN SPECIFIC PROTEASES (UBPs) are able to remove ubiquitin residues from ubiquitinated proteins affecting their stability and function. We identified UBP5 as a novel interactor of Polycomb Repressive Complex 2 (PRC2) subunits and of its associated protein PWWP-DOMAIN INTERACTOR OF POLYCOMBS 1 (PWO1). UBP5 was found directly interacting with 20% of Arabidopsis thaliana genes and the analysis of UBP5 binding regions demonstrated a preferential association at PRC2 recruiting motifs. Disruption of UBP5 activity altered the transcriptional regulation of developmental and stress responsive genes. In addition, in ubp5 mutant plants a global increase of H2A ubiquitination as well as a local increase of H3K27me3 was observed. Here, I will present these and further data demonstrating the impact of UBP5 on plant development through transcriptional regulation and epigenome dynamics.

C1.26 CHROMATIN STRUCTURE ANALYSIS IN PLANT MERISTEMS REVEALS CHANGES ASSOCIATED WITH PLURIPOTENCY MAINTENANCE

Thursday 6 July 2023 09:30

Tamara Lechon (School of Biosciences Cardiff University, United Kingdom), Daniel A Pass (School of Biosciences Cardiff University, United Kingdom), Emily Sornay (School of Biosciences Cardiff University, United Kingdom), James AH Murray (School of Biosciences Cardiff University, United Kingdom), Simon Scofield (School of Biosciences Cardiff University, United Kingdom)

LechonGomezT@cardiff.ac.uk

Plants produce new organs throughout their life cycle thanks to the activity of meristems, which are specialised tissues composed of small populations of stem cells. Cellular pluripotency and differentiation in plant meristems are tightly controlled by complex gene regulatory networks. Previous research has allowed the identification of many genes involved in the gene regulatory network that controls shoot apical

meristem formation and maintenance in the model plantArabidopsis thaliana. However, little is known about the regulation of chromatin structure in plant meristems. The homeodomain transcription factorSHOOT MERISTEMLESS(STM) is essential for maintaining pluripotency in the shoot apical meristem. Here, we map STM binding sites in the Arabidopsis genome using global chromatin immunoprecipitation sequencing analysis and investigate chromatin accessibility at STM target loci using chromatin particle spectrum analysis to study changes in nucleosomal and sub-nucleosomal particle occupancy in differentiated leaf cells compared with undifferentiated leaf cells arising through ectopic expression of STM. Our results reveal global changes in nucleosome positioning around the TSS of target genes involved in maintenance of pluripotency and demonstrate that STM controls the expression of target genes through local changes in chromatin structure.

C1.27 DISPERSAL OF PRC1 CONDENSATES DISRUPTS POLYCOMB CHROMATIN DOMAINS AND LOOPS

Thursday 6 July 2023 09:45

Iain Williamson (University of Edinburgh, United Kingdom), Shelagh Boyle (University of Edinburgh, United Kingdom), Graeme Grimes (University of Edinburgh, United Kingdom), Elias Friman (University of Edinburgh, United Kingdom), Wendy A. Bickmore (University of Edinburgh, United Kingdom)

Iain.Williamson@ed.ac.uk

Polycomb-repressive complex 1 (PRC1) has a strong influence on 3D genome organization, mediating local chromatin compaction as well as localized and chromosome-wide clustering of target loci. Several subunits of PRC1 have been shown to have the capacity to form biomolecular condensates through liquid-liquid phase separationin vitroand when tagged and over-expressed in cells. Here, we use 1,6-hexandiol, which disrupts liquid-like condensates, to examine the role of endogenous PRC1 biomolecular condensates on local and chromosome-wide clustering of PRC1-bound loci. Using imaging and chromatin immunoprecipitation combined with deep sequencing analyses, we show that PRC1-mediated chromatin compaction and clustering of targeted genomic loci – at megabase and tens of megabase length scales – can be reversibly disrupted by the addition and subsequent removal of 1,6-hexandiol to mouse embryonic stem cells. Decompaction and dispersal of polycomb domains and clusters cannot be solely attributable to the reduction of PRC1 binding following 1,6-hexandiol treatment as the addition of 2,5-hexandiol has similar effects on binding despite this alcohol not perturbing PRC1-mediated 3D clustering, at least at the sub-megabase and megabase scales. These results suggest that weak hydrophobic interactions between PRC1 molecules, characteristic of liquid-liquid phase separation, have a role in polycomb-mediated genome organization.

C1.28

Thursday 6 July 2023 10:00

Yanru Li (University of Zürich, Switzerland), Célia Baroux (University of Zurich, Switzerland)

yanru.li@botinst.uzh.ch

Linker histones (H1) are essential architects of the 3D genome in eukaryotes and is a ubiquitous component of chromatin. Our group previously showed that in Arabidopsis, H1 undergoes transient eviction during the differentiation of spore mother cells (SMC), the plant’s germline precursors. Strikingly, H1 eviction precedes a broad range of large-scale chromatin changes affecting both structural organization and the epigenetic landscape. We hypothesise that H1 eviction plays a role in cell fate reprogramming during SMC differentiation, which marks the somatic-to-reproductive transition. To investigate this hypothesis, we first sought to identify the mechanisms controlling H1 eviction then to study the functional impact by altering this event. Based on homology with animal H1, we identified a conserved arginine in the Arabidopsis H1.1 variant (R57) playing an important role. Notably, an R57K but not an R57A mutation impairs H1 eviction in the SMC, leading to changes of epigenetic markers’ landscapes, mitotic division problems and reduced fertility. Furthermore, downregulation of an agmatine iminohydrolase (AIH), an enzyme predicted to catalyze the conversion of arginine in citrulline, recapitulated these phenotypes. Collectively, these observations suggest H1 citrulination in the SMC as a key component regulating H1 eviction and germline fate.

C1.29 MAPPING INTERACTIONS IN BARLEY EMBRYO BY HICHIP

Thursday 6 July 2023 11:00

Pavla Navratilova (Institute of Experimental Botany, Czech Republic), Simon Pavlu (Institute of experimental Botany, Czech Republic), Hana Simkova (Institute of Experimental Botany, Czech Republic)

moussa.benhamed@universite-paris-saclay.fr

Long distance cis- transcriptional gene regulation is believed to require interactions of the target gene promoter and enhancer. Promoters are also thought to interact with each other for co-regulation in transcriptional factories. These interactions can be effectively analyzed in large genomes by Hi-C subtracted using the antibody against RNApolymerase-related histone modification H3K4me3 - a technique called HiChIP. To address interactions of developmental enhancers in a diploid cereal, we used barley embryos. The resulting interactions were then integrated with multiple other epigenomic datasets revealing a large number of promoter-promoter interactions involving preferentially certain types of promoter/gene. The promoter-enhancer interactions were also analyzed, revealing the extent of this type of regulation in one of the main crops.

Thursday 6 July 2023 09:00

Moussa Benhamed (University of Paris-Saclay, France)

C1.30 EXPLORING THE CHROMATINBASED REGULATION OF ENHANCER PROMOTER CONTACT AND ITS IMPACT ON GENE EXPRESSION IN TOMATO

H1 CITRULINATION –AN ATYPICAL MODIFICATION REGULATING GERMLINE FATE IN ARABIDOPSIS

sara.farrona@universityofgalway.ie

The complex and dynamic three-dimensional organization of chromatin within the nucleus makes understanding the control of gene expression challenging, but also opens up possible ways to epigenetically modulate gene expression. Because plants are sessile, they evolved sophisticated ways to rapidly modulate gene expression in response to environmental stress, that are thought to be coordinated by changes in chromatin conformation to mediate specific cellular and physiological responses. However, to what extent and how stress induces dynamic changes in chromatin reorganization remains poorly understood. Here, we comprehensively investigated genome-wide chromatin changes associated with transcriptional reprogramming response to heat stress in tomato. Our data show that heat stress induces rapid changes in chromatin architecture, leading to the transient formation of promoter-enhancer contacts, likely driving the expression of heat-stress responsive genes. Furthermore, we demonstrate that chromatin spatial reorganization requires HSFA1a, a transcription factor (TF) essential for heat stress tolerance in tomato. In the light of our findings, we propose that TFs play a key role in controlling dynamic transcriptional responses through 3D reconfiguration of promoter-enhancer contacts.

marker. The analysis revealed a high heterogeneity in nuclear shape and chromatin distribution patterns in iPSC culture, measurable with the entropy of morphological descriptors and texture features. Strikingly, heterogeneity strongly reduces over time. This process is stronger in the absence of phytohormones but reduced when cells are exposed to TSA, a drug inhibiting histone deacetylation. Collectively, our data suggest that, fresh iPSC culture have a high entropy in chromatin organisation pattern and that chromatin dynamics is controlled by antagonistic external (phytohormones) and internal (epigenetic) factors.

C1.32 BDH1 AND BDH2 - MISSING ELEMENTS IN UNDERSTANDING SWI/ SNF COMPLEXES IN ARABIDOPSIS THALIANA?

Thursday 6 July 2023 11:45

C1.31 HETEROGENEITY

OF CHROMATIN DISTRIBUTION PATTERNS IN PLANT

Thursday 6 July 2023 11:30

Célia Baroux (University of Zurich Institute of Plant and Microbial Biology Plant Developmental Genetics Switze, Switzerland), Kinga Rutowicz (University of Zurich Institute of Plant and Microbial Biology Plant Developmental Genetics Switze, Switzerland), Elizabeth Kracik-Dyer (University of Zurich Institute of Plant and Microbial Biology Plant Developmental Genetics Switze, Switzerland), Joel Lüthi (University of Zurich Department of Molecular Life Sciences Switzerland, Switzerland), Reinoud De Groot (University of Zurich Department of Molecular Life Sciences Switzerland, Switzerland), René Holtackers (University of Zurich Department of Molecular Life Sciences Switzerland, Switzerland), Yauhen Yakimovich (University of Zurich Department of Molecular Life Sciences Switzerland, Switzerland), Olivier Gandrillon (Ecole Normale Supérieure de Lyon Laboratoire de Biologie et Modélisation de la Cellule France, France), Lukas Pelkmans (University of Zurich Department of Molecular Life Sciences Switzerland, Switzerland)

cbaroux@botinst.uzh.ch

The release of plant cells devoid of cell wall into culture, protoplasts, leads to profound alterations in transcriptome profiles and chromatin organisation compared to the source tissue. Notably, large-scale heterochromatin decondensation was reported earlier to be a hallmark of freshly released protoplasts, which we find here to correlate with reduced levels of linker histones. We further investigated the euchromatin compartment by super resolution imaging and found significant changes at the nanoscale, with an increased volume of the inter-chromatin compartment. Furthermore, protoplasts are often considered ‘plant iPSCs’ in analogy to animal induced pluripotent stem cells, due to their ability to regenerate tissues or whole plants under appropriate conditions. To capture the breadth of chromatin dynamics in iPSC cultures we established a high-throughput imaging – image processing workflow based on a dual H1.2-GFP; H2B-RFP chromatin

Katarzyna Kapela (University of Warsaw, Poland), Ewelina Małecka-Matejuk (University of Warsaw, Poland), Paulina Stachula (Institute of Biochemistry and Biophysics PAS, Poland), Rafał Archacki (University of Warsaw, Poland) k.kapela@student.uw.edu.pl

SWI/SNF chromatin remodelers are evolutionarily conserved multiprotein complexes that use the energy of ATP hydrolysis to change chromatin structure. The SWI/SNF family is represented in Arabidopsis thaliana by four chromatin remodeling ATPases: SPLAYED (SYD), BRAHMA (BRM), MINUSCULE1, and MINUSCULE2. BRM is the only subunit with the C-terminal bromodomain (a protein motif capable of binding to acetylated histones) and is therefore considered to be the closest homolog of yeast and animal ATPases. Recently, novel members of plant SWI/SNF complexes have been characterized, including BDH1 and BDH2 proteins that are homologs of BCL7a/b/c subunits of mammalian SWI/SNF. Analyses of single and double bdh mutants indicated that BDH1 and 2 act redundantly to control vegetative development and flowering, as well as responses to abscisic acid and paclobutrazol, an inhibitor of gibberellin biosynthesis. However, the role of BDH and BCL7 within the plant and mammalian SWI/SNF complexes is still very much unknown. Here we study protein-protein interactions of BDH1 and BDH2 with other subunits of SWI/SNF complexes, the impact of bdh1/2 mutations on the protein levels of BRM, and genetic interactions of BDH1/2 with BRM ATPase. We show that the bdh1/2 mutant strongly enhances the effects of knockout and hypomorphic mutations in BRM, indicating that BDH1 and BDH2 play an important role in the functioning of SWI/SNF complexes in Arabidopsis.

C1.33 TISSUE-SPECIFIC EPIGENOMIC SIGNATURES PUNCTUATE PLANT SPECIALISED METABOLISM PATHWAYS IN CANNABIS SATIVA GLANDULAR TRICHOMES

Thursday 6 July 2023 12:00

Lee J. Conneely (La trobe university, Australia), Mathew G. Lewsey (La Trobe University, Australia)

leejconneely@gmail.com

Epigenomic marks, such as histone modifications and DNA methylation, influence gene regulation. To understand how epigenomic marks influence expression of genes involved in C. sativa specialised metabolism, we have generated genome wide epigenomic maps of four histone post-translational modifications in glandular trichomes, fan leaves, and stems. Both conserved and differential epigenomic patterning was observed between the tissues, reflecting tissuespecific function. The histone modifications H3K4me3 and H3K56ac, extensively documented in other systems for their association with the transcriptional start sites of active genes, were enriched at transcriptional start sites of many specialised metabolism genes only in glandular trichomes. Noteworthy examples included the cannabidiolic acid synthase, tetrahydrocannabinolic acid synthase, olivetol synthase, and geranylgeranyl pyrophosphate synthase large and small subunit genes. These same specialised plant metabolism genes were depleted for the active transcriptional marks in both fan leaves and stems, where they were instead enriched for the well-known transcriptionrepressive histone mark H3K27me3.

We have also integrated our epigenomic histone modification maps with corresponding tissue-specific transcriptomic data. This permits us to better interrogate the genome-scale regulatory effects of the histone modifications and their relationship to tissue-specific gene regulation. Although the histone marks tested in this study are widely documented and display conserved functionality with respect to transcription across Eukarya, they have yet to be documented in C. sativa. We hope that this work will provide a useful tool for further epigenetics research in C. sativa.

C1.34 GENOME-WIDE SINGLE-MOLECULE ANALYSIS OF LONG-READ DNA METHYLATION REVEALS HETEROGENEOUS

PATTERNS AT HETEROCHROMATIN

Thursday 6 July 2023 12:15

Duncan Sproul (University of Edinburgh, United Kingdom), Lyndsay Kerr (University of Edinburgh, United Kingdom), Ioannis Kafetzopoulos (University of Edinburgh, United Kingdom), Ramon Grima (University of Edinburgh, United Kingdom)

d.sproul@ed.ac.uk

Whole-genome bisulfite sequencing is central to our current understanding of the human methylome. This technology can probe single-molecule methylation patterns, but limits analyses to reads of a few hundred basepairs. DNA methylation can also be directly detected using Nanopore sequencing which can generate reads measuring megabases in length. However, thus far these analyses have focused on bulk-level assessment of DNA methylation. Here we analyse DNA methylation in single Nanopore reads with a mean length of 24.6kb, to show that bulk-level metrics underestimate large-scale heterogeneity in the methylome. We use the correlation in methylation state between neighbouring sites to quantify single-molecule heterogeneity across the genome and find that heterogeneity varies significantly across the human genome – with some regions having heterogeneous methylation patterns at the single-molecule level and others possessing more homogeneous methylation patterns. By comparing the genomic distribution of the correlation to epigenomic annotations, we find that the greatest heterogeneity in single-molecule patterns is observed within heterochromatic partially methylated domains. By analysing the patterns in single molecules in more detail, we show the existence of a 180bp periodicity in DNA methylation that accounts for some of the heterogeneity we uncover in long single-molecule DNA methylation

patterns and is likely induced by nucleosomes. Moreover, we find that this periodic structure is largely masked in bulk data in a manner that is consistent with imperfect phasing of nucleosomes between molecules. Our findings demonstrate the power of single-molecule analysis of long-read data to understand the structure of the human methylome.

C1.35 REGULATORY AND TOPOLOGICAL PERTURBATION AT A HUMAN DISEASE LOCUS

Thursday 6 July 2023 14:30

Hannah K Long (University of Edinburgh MRC Human Genetics Unit, United Kingdom), Liang-Fu Chen (Stanford University, United States), Alistair N Boettiger (Stanford University, United States), Joanna Wysocka (Stanford University, United States)

hannah.long@ed.ac.uk

Enhancer clusters (ECs) greater than 1.25 megabases upstream of SOX9 are frequently ablated in Pierre Robin sequence (PRS) patients exhibiting lower jaw hypoplasia. We previously characterised the activity of these ECs in facial progenitor cells (cranial neural crest cells, CNCCs) and quantified the impact of EC ablation on gene expression and craniofacial morphological development. To explore mechanisms facilitating extreme long-range regulation at this locus, we utilised optical reconstruction of chromatin architecture (ORCA) imaging to trace 3D locus topology during PRS EC activation. We observed pronounced changes in locus topology during CNCC differentiation from pluripotent stem cells and determined that these ensemble-average differences arise through changes in the frequency of commonly sampled topologies – an observation made possible through analysis of ORCA single chromatin fibre traces. We further identified two CTCFbound elements, internal to the SOX9 topologically associating domain, which promote stripe formation, are positioned near the domain’s 3D geometric centre and bridge enhancer-promoter contacts in a series of chromatin loops. Ablation of these elements results in diminished SOX9 expression and altered domain-wide contacts. Polymer models with uniform loading across the domain and frequent cohesin collisions recapitulate this multiloop, centrally clustered geometry. Together, we provide mechanistic insights into gene regulation over ultra-long genomic ranges, involving distal enhancer clusters and structural elements that mediate architectural stripe formation.

Thursday 6 July 2023 15:00

C1.36 LINKER HISTONE H1

DIFFERENTIALLY IMPACTS THE POLYCOMB CHROMATIN LANDSCAPE AT GENES AND TELOMERIC REPEATS IN ARABIDOPSIS

Fredy Barneche (IBENS - CNRS, France), Gianluca Teano (IBENS, France), Lorenzo Concia (IBENS, France), Ivona Biocanin (IBENS, France), Léa Wolff (IBENS, France), Léopold Carron (LCQB - IBPS, France), Vincent Colot (IBENS, France), Ueli Grossniklaus (UZH, Switzerland), Bowler Chris (IBENS, France), Schrumpfová Procházková (CEITEC, Czech Republic), Carbone Alessandra (LCQB - IBPS, France), Aline Probst (GReD CNRS, France), Jiri Fajkus (CEITEC, Czech Republic), Célia Baroux (UZH, Switzerland), Simon Amiard (GReD CNRS, France), Stefan Grob (UZH, Switzerland), Leandro Quadrana (IPS2, France), Clara Bourbousse (IBENS, France)

barneche@bio.ens.psl.eu

Linker histones play a pivotal role in shaping chromatin architecture, yet their functional interplays with chromatin factors along the epigenome landscape are just starting to emerge. For example, H1 central function in instructing genome topology by favoring H3K27me3 deposition has only recently been established in vivo (Yusufova et al, Nature 2020) while the molecular mechanisms explaining how H1 drives sequence-specific mechanisms remain poorly explored. Here we report that, in Arabidopsis thaliana, H1 triggers contrasted chromatin status at distinct chromosome domains through interplay with PRC2 activity. More precisely, we identified that histone H1 favors H3K27me3 enrichment and dampens chromatin accessibility at a majority of PRC2 target genes while oppositely preventing H3K27me3 deposition at large blocks of telomeric sequences abutting centromeres (Interstitial Telomeric Sequences, ITS). Mechanistically, the protective effect of H1 at ITSs relies in its capacity to hinder DNA association of Telomeric Repeat Binding (TRB) proteins, which possess a H1-like DNA binding domain and mediate PRC2 cis-recruitment, to the DNA (Zhou et al, Nature Genetics 2018). Hence, we propose that competition between H1 and TRB-PRC2 underlies a heretofore-ignored sequence-specific ability of H1 to act as a safeguarding mechanism allowing plants to cope with the intrinsic attractiveness of telomeric motifs for PRC2. This mechanistic framework may prevent deleterious consequences of ITS neo-formation/expansion on H3K27me3 homeostasis and genome topology, which we are now exploring using the great natural variability of ITSs in A. thaliana accessions.

C1.37 A GENOME-WIDE COMPREHENSIVE ANALYSIS OF NUCLEOSOME POSITIONING IN YEAST

Thursday 6 July 2023 15:15

Leo Zeitler (University of Paris-Saclay, France), Cyril Denby Wilkes (University of Paris-Saclay, France), Julie Soutourina (University of Paris-Saclay, France), Arach Goldar (University of Paris-Saclay, France)

leo.zeitler@i2bc.paris-saclay.fr

The one-dimensional DNA molecule needs to be tightly packaged into the spatially constraining nucleus. Folding is achieved on its lowest level by wrapping DNA around nucleosomes. Their positioning strongly regulates other nuclear processes, such as transcription and repair. Despite strong efforts to study nucleosome phasing using NGS data, the mechanism of their collective arrangement along the gene remains largely unknown. Most studies either focus on maintenance of Nucleosome Depleted Regions (NDR), or they measure average linear correlation of up to 4 nucleosomes into the gene, ignoring location-dependent specifics. Here, we assess the genome-wide

nucleosome profile of Saccharomyces cerevisiae yeast genes using Functional Principal Component Analysis. By decomposing the NGS signal into its two main descriptive functions, we compared wild type and chromatin remodeler deleterious strains, keeping positionspecific details preserved. Based on the data, we determine two neatly separated clusters of genes, which can be easily set into context with other nuclear properties, such as sequence composition and RNA polymerase II presence. Notably, none of the supposed influencing factors can easily explain coordinated phasing along the gene, although their interdependence clearly changes within mutant strains. This indicates that ATP-dependent chromatin remodelers strongly influence nucleosome organisation along transcribed regions with distinct effects. Most surprisingly, the analysis clearly suggests that RSC chromatin remodeler is not only responsible for NDR maintenance, but also decouples nucleosome arrangement within the gene from phasing outside, which interfere in mutant conditions. We propose that this unknown RSC function is pivotal for independent gene expression.

C1.38 TRBS: THE FAMOUS FIVE IN TRANSCRIPTIONAL REGULATION

Thursday 6 July 2023 15:30

Aline Probst (Genetics Reproduction and Development Institute, France), Simon Amiard (Genetics Reproduction and Development Institute, France), Léa Feit (Genetics Reproduction and Development Institute, France), Clara Bourbousse (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Fredy Barneche (Institut de biologie de l’Ecole normale supérieure (IBENS), France)

aline.probst@uca.fr

Regulation of gene expression during development requires transcriptional repression by the Polycomb system. In Arabidopsis, Polycomb Repressive Complex 2 (PRC2) activity can be recruited to target genes by TELOMERE REPEAT BINDING (TRB)1, TRB2 and TRB3 proteins, which recognize telobox motifs in promoters of numerous developmental genes via their Myb/SANT domain. Here we address the role of the remaining members of the TRB family: TRB4 and TRB5. Unlike trb1 trb2 trb3 mutants, trb4 trb5 lossof-function plants are viable and fertile, but show developmental growth defects including delayed flowering. Loss of TRB4 and TRB5 leads to the misregulation of several hundred genes, most of which are different from the differentially regulated genes in the trb1 trb2 trb3 mutant suggesting that TRB4 and TRB5 may have distinct roles compared to the other members of this family. This aspect is supported by the early appearance and the conservation of two distinct TRB subfamilies in seed plants and by our ChIP-seq analyses, which revealed that TRB4 shares only part of its binding sites with TRB1. To unravel the connections between TRB family members, we investigated the physical and genetic interactions between the different TRB family members and analyzed the role of TRB4 and TRB5 in H3K27me3 deposition.

C1.39 UNDERSTANDING THE LINK BETWEEN 3D GENE STRUCTURE AND TRANSCRIPTION BY COMPUTER SIMULATIONS

Thursday 6 July 2023 16:30

Davide Marenduzzo (The University of Edinburgh, United Kingdom)

Davide.Marenduzzo@ed.ac.uk

Classical experiments suggest a link between 3D gene structure and transcription, but this idea has been challenging to directly test quantitatively in the lab. I will discuss a different approach using computer simulations based on biophysical principles of genome organisation to simultaneously predict 3D structure and transcriptional output of human chromatin genome wide (seehttps://3dgene.igc. ed.ac.uk).

Our model is validated by comparison to GRO-seq and RNAseq (for transcription) and to Hi-C and FISH (for 3D structure). Our simulations allow us first to identify a functional role for intranuclear microphase separation in transcription, associated with the clustering of polymerases, transcription factors and genomic binding sites. We also use our simulations to propose a molecular mechanism underlying transcriptional noise, which relies on heterogeneity of chromatin loop networks and on loop extrusion.

C1.40 ULTRA-LONG-RANGE INTERACTIONS BETWEEN ACTIVE REGULATORY ELEMENTS

Thursday 6 July 2023 17:00

Sara Farrona (University of Galway, Ireland), Godwin James (University of Galway, Ireland), Mohan Govindasamy (University of Galway, Ireland), Kiruba Nedounsejian (University of Galway, Ireland)

Elias.Friman@ed.ac.uk

Contacts between enhancers and promoters are thought to relate to their ability to activate transcription. Investigating mechanisms that drive such chromatin interactions is therefore important for understanding gene regulation. We have determined contact frequencies between millions of pairs of cis-regulatory elements from chromosome conformation capture datasets and analysed a collection of hundreds of DNA-binding factors for binding at regions of enriched contacts. This analysis revealed enriched contacts at sites bound by many factors associated with active transcription. We show that active regulatory elements, independent of cohesin and polycomb, interact with each other across distances of 10s of megabases in vertebrate and invertebrate genomes and that interactions correlate and change with activity. However, these ultra-long-range interactions are not dependent on RNA polymerase II transcription or several transcription cofactors. We propose that long-range interactions between cisregulatory elements are driven by three distinct mechanisms – cohesinmediated loop extrusion, polycomb contacts, and association between active regions.

C1.41 BIOM3D, A MODULAR DEEP LEARNING FRAMEWORK FOR 3D BIOIMAGE SEGMENTATION

Thursday 6 July 2023 17:15

Guillaume Mougeot (Oxford Brookes University, United Kingdom), Sophie Desset (IGReD, France), Frédéric Chausse (Institut Pascal, France), Katja Graumann (Oxford Brookes University, United Kingdom)

19137682@brookes.ac.uk

Despite the promises, deep learning (DL) techniques using artificial neural networks are slow to spread for the segmentation of threedimensional (3D) biomedical images. A first obstacle comes from the difficulty of implementing them: the new methods published are often proofs of concept obtained on “toy” datasets. Their use with “real” biomedical data often fails because 3D images are much more difficult to manipulate than 2D images due to computer memory issues. A second obstacle is the lack of comparative analysis with non-DL techniques on experimental datasets to measure if there is an actual added value of DL techniques. Out of 106 publications of DL methods that can segment 3D images of nuclei, only 6 offer the code, the documentation, and the dependencies, which are essential for their implementation (Mougeot et al., JCellScience 2022). We compared the predictions of these 6 methods with the segmentation masks obtained with a specialized tool, NucleusJ, on our own dataset. Only nnU-Net performs better than NucleusJ. However, nnU-Net is very difficult to use, so we have completely restructured this method by creating a new modular framework, Biom3d. Biom3d responds to a continuum of user profiles ranging from biologists to DL developers and has the same performance as nnU-Net when used in generic mode but has the potential to exceed nnU-Net by adding or modifying modules.

C1.42 ON THE ROLE OF POLYMERASES IN REGULATING THE 4D GENOME

Thursday 6 July 2023 17:30

Daniel Jost (CNRS - ENS de Lyon, France), Hossein Salari (CNRS - ENS de Lyon, France), Dario D'Asaro (CNRS - ENS de Lyon, France), Maxime Tortora (CNRS - ENS de Lyon, France), Genevieve Fourel (INSERM - ENS de Lyon, France), Cedric Vaillant (CNRS - ENS de Lyon, France), Jean-Michel Arbona (CNRS - ENS de Lyon, France)

daniel.jost@ens-lyon.fr

RNA and DNA Polymerases are key molecular motors playing central roles in fundamental processes like transcription and replication. I'll present our current effort to understand how they may also actively participate in orchestrating the spatio-temporal dynamics of the genome. Using analysis of Hi-C data in yeast and mammals and biophysical modeling, I'll show how the formation of transient transcription and replication factories may dynamically and stably shape the 3D genome.

C1.43 OF SNAILS AND MEN: SIMILARITIES BETWEEN THE MOLLUSCAN MODEL ORGANISM, BIOMPHALARIA GLABRATA WITH HUMANS, WITH RESPECT TO NUCLEAR AND GENOME BEHAVIOUR IN YOUNG AND OLD CELLS.

Friday 7 July 2023 09:00

Joanna M Bridger (Brunel University London, United Kingdom), Daniel A Horton (Brunel University London, United Kingdom), Halime D Arican-Goktas (Brunel University London, United Kingdom), Michael Smith (University of the District of Colombia, United States), Nana Adjoa Pels (University of the District of Colombia, United States), Swara Yadav (University of the District of Colombia, United States), Oumsalama Elhelu (University of the District of Colombia, United States), Simone Parn (University of the District of Colombia, United States), Victoria Mann (George Washington University, United States), Paul J Brindley (George Washington University, United States), Gabriel Rinaldi (Aberystwyth University, United Kingdom), Matty Knight (University of the District of ColombiaGeorge Washington University, United States)

joanna.bridger@brunel.ac.uk

Biomphalaria glabratais a tropical fresh water snail and is the major intermediary host of the parasite Schistosoma mansoni causing Schistosomiasis/Bilharzia in 250M people. The miracidia infect snails by burrowing into them, but remaining extra-cellular. After a number of weeks cercariae emerge from the snail and then burrow through the skin of humans in contact with the water.

B. glabratahas had its genome sequenced and is the molluscan model organism of choice for studies from pathogenesis, neurobiology, environmental toxicology, climate change, cancer mechanisms and now ageing.

Shortly after infection of the snails specific genes such as the heat shock protein (hsp) genes, hTERT and piwi are upregulated, which aid the parasite in its infectivity. We have studied spatial aspects of the mechanism of the induction of gene expression by the parasite and have modelled it with a short heat shock to the snails. There is spatial non-random relocation of genes, that is prior to upregulation, to RNA polymerase II accumulations and this relocation is mediated by the nuclear motor protein complex, containing the snail homologue of the nuclear myosin 1b. This seems to be a similar mechanism that is found for whole chromosomes and HSP genes in human cells, and is inhibited by the same compounds, consequently affecting transcription.

Interestingly, this transcription-associated relocation mechanism is not functional in human senescent cells, nor in aged snails. Bringing to the foreB. glabrataas a new model for ageing studies and analysis of specific senotherapeutics, drugs that lead to healthier longevity.

C1.44 INTERPLAY BETWEEN COHESIN AND CONDENSIN SHAPES MITOTIC CHROMOSOMES

Friday 7 July 2023 09:30

Kumiko Samejima (University of Edinburgh, United Kingdom), Johan H. Gibcus (University of Edinburgh, United Kingdom), Sameer Abraham (University of Edinburgh, United Kingdom), Fernanda Cisneros Soberanis (University of Edinburgh, United Kingdom), Itaru Samejima (University of Edinburgh, United Kingdom), Job Dekker (University of Edinburgh, United Kingdom), Leonid A. Mirny (University of Edinburgh, United Kingdom), William C. Earnshaw (University of Edinburgh, United Kingdom), Anton Goloborodko (University of Edinburgh, United Kingdom)

kumiko.samejima@ed.ac.uk

Cohesin and Condensin are Structural Maintenance of Chromosomes (SMC) complexes that are essential for the organisation and stability of genomic DNA throughout the cell cycle. It has been generally believed that cohesin organises interphase chromatin and then holds the two sister chromatids together until anaphase onset during mitosis. On the other hand, condensin is essential to form rod-shaped mitotic chromosomes. We have been investigating the roles of SMC complexes in mitotic chromosome assembly using chicken DT40 cells acutely depleted of cohesion and/or condensin I and/or II. These cells express an analogue sensitive CDK1 kinase (CDK1as) and exhibit near-perfect synchronous mitotic entry, with auxin-inducible degron technology enabling rapid depletion of target protein(s) just prior to mitotic entry. Our quantitative proteomic data reveal that, surprisingly, a substantial amount of cohesin remains associated with chromosome arms until late prometaphase. The presence of cohesin between arms of sister chromatids in early prometaphase was confirmed by using GFP-knock-in cell lines. Our interdisciplinary collaborative analysis, which includes high-end microscopy, Hi-C, and polymer modelling reveals an interplay in which cohesin and condensin play essential roles to remove interphase chromatin organisation and in mitotic chromosome formation during early mitosis. We will present a newly updated model of mitotic chromosome organisation.

C1.45 THE CENTROMERE TARGETING MECHANISM OF KNL2 AND CENP-C PROTEINS

Friday 7 July 2023

09:45

Inna Lermontova (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany), Ulkar Ahmadli (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany), Aditya Sinha (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany), Sheng Zuo (Masaryk University, Czech Republic), Manikandan Kalidass (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany)

lermonto@ipk-gatersleben.de

In most eukaryotic organisms correct segregation of chromosomes during cell divisions requires presence of the centromeric histone H3 variant (CENH3).

Previously we have identified and characterized the first plant CENH3 assembly factor KINETOCHORE NULL2 (KNL2) (Lermontovaet al., 2013).

Our following study revealed a CENH3 nucleosome binding motif at the C terminus ofArabidopsisKNL2, named CENPC-k due to its similarity to the CENPC motif of the CENP-C protein. Centromeric localization of KNL2 was abolished by deletion of the CENPC-k motif and by mutating single conserved amino acids, but can be restored by insertion of the corresponding motif ofArabidopsisCENP-C (Sandmannet al., 2017). In addition, the C-terminus of KNL2 demonstrated CENPC-k-independent DNA-binding capacity.

Here we show that the CENPC-k and CENPC motifs alone are not sufficient for targeting centromeres. Therefore, we hypothesized that the targeting efficiency of KNL2 and CENP-C to centromeres could be determined by the CENPC(k) motif together with the DNA-binding region(s). We performedin silicoanalysis of both proteins and identified DNA-binding regions located at both sides of the CENPC-k and CENPC motif. Indeed, the fusion of protein fragments including the CENPC(k) motif and DNA-binding regions with EYFP resulted in efficient centromeric targeting in transiently transformed tobacco and stably transformedArabidopsis. Whereas deletion of the DNA-binding regions of the C-terminal part of KNL2 strongly reduced its centromeric localisation.

Thus, we conclude that KNL2 and CENP-C proteins target centromeres via CENPC-k and CENPC motifs and anchor to centromeres via binding of centromeric DNA.

C1.47 FROM LIPODYSTROPHY TO MUSCULAR DYSTROPHY, A GRADIENT OF METABOLIC DISORDERS DUE TO GENOME MISORGANIZATION

Friday 7 July 2023 10:15

Eric C. Schirmer (University of Edinburgh, United Kingdom)

e.schirmer@ed.ac.u

Friday 7 July 2023 10:00

Naiming Chen (University of Edinburgh, United Kingdom)

Naiming.Chen@ed.ac.uk

During cell division, not only the DNA sequence, but also the epigenetic modifications and the 3D conformation of chromatin have to be transmitted to the daughter cells, in order to maintain cell identity. The genome duplication takes place following a chronological order, referred to as the replication timing (RT) program, intimately interconnected with the genome three-dimensional organisation. However, the molecular mechanisms underlying the coordination of the RT program and the architecture of chromatin organisation, as well as the biological significance of this coordination are still unclear. RIF1 is a key regulator of both the temporal organisation of genome replication and of nuclear architecture. This suggests that RIF1 could serve as a convergent regulator, yet the molecular mechanisms how RIF1 coordinate both processes remain elusive. Here, we report that RIF1, in association with protein phosphatase 1(PP1), is required for the timely dephosphorylation of H3S10ph during the window when nuclear organisation and replication timing is re-established after mitosis. Importantly, RIF1-PP1 complex is required for the correct repositioning and re-establishment of epigenetic identity of specific genomic regions. Therefore, we will present evidence supporting the idea that RIF1-dependent regulation of chromatin contacts compartmentalisation and sub-nuclear distribution of chromatin is regulated primarily through the timely dephosphorylation of H3S10ph.

Genome regions in contact with the nuclear envelope tend to be repressed so that recruitment of particular genes to the nuclear envelope adds a further layer to gene regulation that contributes to tissueness. Accordingly, each tissue has a particular pattern of 3D genome organization that apparently optimizes gene expression for that tissue. Mutations in nuclear envelope proteins that establish these patterns of genome organization yields disruption of a particular genome organization that results in disorders such as lipodystrophy and muscular dystrophy. We have made a mouse model with disruption of a fat-specific nuclear envelope protein regulating genome organization in adipogenesis that has a lipodystrophy phenotype and another mouse model with disruption of a muscle-specific nuclear envelope protein regulating genome organization in myogenesis that has a muscular dystrophy phenotype. Interestingly, both exhibit a combination of loss of their tissue differentiation while also exhibiting a de-repression of the other tissue pathway i.e. the lipodystrophy mouse has myogenesis and muscle metabolism genes inappropriately expressed and the muscular dystrophy mouse has adipogenesis and fat metabolism genes inappropriately expressed. A central question that needs to be addressed is to what extent loss of differentiation and to what extent de-repression of alternate differentiation pathways contribute to pathologies, but it is interesting that RNA-Seq analysis of EmeryDreifuss muscular dystrophy patients reveals considerable changes in metabolic outputs and a similar de-repression of fat metabolism genes in muscle cells.

C1.48 DYNAMICS OF NUCLEAR ORGANIZATION AND FUNCTION UPON QUIESCENT ENTRY AND RETURN TO GROWTH

Friday 7 July 2023 11:00

Angela Taddei (Institut Curie, France)

angela.taddei@curie.fr

Unicellular organisms finely tune their growth and behavior to their environment, adapting to nutritional depletion or stresses by engaging specific metabolic and developmental programs. In particular, upon exhaustion of nutrients, a subpopulation of S. cerevisiae reversibly exits the cell cycle and differentiates into a quiescent state (a phenomenon common among pathogens). The genome of these “Q cells” adopts a very specific conformation associated with a massive decrease in transcriptional activity, two features that contribute to Q cell longevity (Guidi et al, 2015; McKnight et al, 2015). Importantly, both transcriptional activity and genome conformation are rapidly restored when nutrients are provided. Return to growth is a key step for survival in a competitive environment and requires restoring the transcriptional program adapted to the available resources. I will discuss our last results on the dynamics of genome (un)folding during quiescence entry and return to growth in relation with transcriptional activity.

C1.46 EPIGENETIC INHERITANCE IS COORDINATED WITH REPLICATION TIMING THROUGH RIF1-DEPENDENT TIMELY DEPHOSPHORYLATION OF H3S10PH

C1.40 LINKER HISTONE H1.3 LINKS TOR SIGNALING TO NUCLEAR ARCHITECTURE AND ACTIVITY DURING ARABIDOPSIS PHOTOMORPHOGENESIS

Friday 7 July 2023

11:30

Geoffrey Schivre (Institut de biologie de l’Ecole normale supérieure (IBENS) Ecole normale supérieure CNRS INSERM, France), Imen Mestiri (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Gianluca Teano (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Léa Wolff (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Lorenzo Concia (Institut de biologie de l’Ecole normale supérieure (IBENS), France), AF DetonCabanillas (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Chris Bowler (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Clara Bourbousse (Institut de biologie de l’Ecole normale supérieure (IBENS), France), Fredy Barneche (Institut de biologie de l’Ecole normale supérieure (IBENS), France)

barneche@bio.ens.psl.eu

Upon germination under the soil surface, plants need to cope with the lack of light energy source. The metabolic reserves stored in the seed are preferentially allocated to hypocotyl elongation toward the soil surface whereas cotyledon development is poised until light is perceived upon soil emergence, which triggers the transition to photoautotrophy. We previously reported that upon prolonged etiolated development Arabidopsis cotyledonnuclei have a relaxed heterochromatin and an overall attenuation of the transcriptional activity. Here we report that reduction of heterochromatin aggregation in darkness relies on the atypical linker histone variant H1.3. Upon light exposure, H1.3 is rapidly degraded (~12 h), thereby enabling heterochromatinization. H1.3 ChIP-seq profiling in dark-grown cotyledons further identified that, contrasting to canonical linker histones, this variant is enriched at the 5’ end of most genes where it could dampen RNA Pol II progression. We further report that sugar supplementation prevents H1.3 expression in darkness while restoring heterochromatinization and RNA Pol II processivity. Finally, we report an unexpected link between TOR, a conserved energy sensor that coordinate plant responses and cell metabolism, and H1.3 expression, which may mediate a functional framework linking the energetic status to nuclear architecture and the transcriptional regime.

C1.50 ASSESSING THE FUNCTIONS OF HISTONE ADP-RIBOSYLATION DURING THE DNA DAMAGE RESPONSE

Friday 7 July 2023 11:45

Judith Miné-Hattab (Sorbonne University, France), Fabiola García Fernández (Sorbonne University, France), Catherine Chapuis (University of Rennes, France), Angela Taddei (Sorbonne University, France), Sébastien Huet (University of Rennes, France)

ADP-ribosylation signaling by PARP1 is a key early event of the DNA damage response (DDR). PARP1 recruitment occurs within seconds upon DNA damage, triggering the accumulation of ADP-ribose binding repair factors and the relaxation of the surrounding chromatin. While

recent work has elucidated the role of PARP1 auto-ADP-ribosylation, less is known about the impact of the ADP-ribosylation of histones. The aim of this project is to study how histone ADP-ribosylation modulates chromatin folding immediately after DNA damage nearby lesions and to unveil its potential functions in the DDR. To this end, we have characterized chromatin architecture at the single nucleosome level using an innovative set-up based on single-molecule imaging combined with laser-micro-irradiation. Our results showed that H2B motions increase transiently 30s after irradiation, which correlates with PARP1 recruitment and chromatin relaxation. This increased dynamic is restricted to histones located within the irradiated area, suggesting a specific response to DNA damage. PARP inhibition fully suppressed increased histone dynamics correlating with early results indicating the central role of ADP-ribosylation signaling in early chromatin remodeling. Furthermore, to know which ADP-ribosylation target is the source of enhanced histone mobility observed after irradiation, we assessed histone tracking upon re-expression of different PARP1 mutants in PARP1 knockout cells. We found that a PARP1 mutant showing deficient auto-modification was still able to promote increased histone dynamics at DNA lesions, in contrast to another PARP1 mutant unable to perform histone ADP-ribosylation. Taken together, these results highlight the central role of histone ADP-ribosylation in chromatin remodeling during the DDR.

C1.51 UV-INDUCED MODULATION OF

CONSTITUTIVE HETEROCHROMATIN SHAPE DURING PHOTODAMAGE REPAIR IN ARABIDOPSIS THALIANA

Friday 7 July 2023 12:00

Jean Molinier (Institut de biologie moléculaire des plantes Strasbourg France, France), Philippe Johann to Berens (Institut de biologie moléculaire des plantes Strasbourg France, France), Jackson Peter (Institut de biologie moléculaire des plantes Strasbourg France, France), Sébastien Staerck (Institut de biologie moléculaire des plantes Strasbourg France, France)

jean.molinier@ibmp-cnrs.unistra.fr

In the last decades many studies reported evidence for various interplays between DNA repair pathways and the epigenomic landscape. This includes the epigenetically related DNA damageability, the specific damage repair processes and the role of these interconnected mechanisms in (epi)genome maintenance and plasticity.

Interestingly, the epigenetic context of the damaged genomic regions defines by which repair pathways lesions will be processed. For example, UV-induced DNA damage occurring in genomic regions with an epigenetic landscape allowing transcription are repaired by the Transcription Coupled Repair pathway. Conversely, the compacted heterochromatic regions, un-transcribed or poorly transcribed, are predominantly repaired by the Global Genome Repair. The exact mechanisms by which these repair pathways recognize and process photodamaged DNA sequences wrapped around nucleosomes remain to be better deciphered. In addition, the accurate re-establishment of the epigenomic landscape upon repair appears to be an important step in the maintenance of (epi)genome integrity. We identified a cooperative mode of action of histone post-translational modifications homeostasis and excision repair of UV-induced DNA damage that allows efficient removal of photolesions within constitutive heterochromatin.

C2 - BIG DATA BIOLOGY

ORGANISED BY: CRANOS WILLIAMS (NORTH CAROLINA STATE UNIVERSITY), ROSS SOZZANI (UNIVERSITY OF PAVIA), VERONICA GRIENEISEN (CARDIFF UNIVERSITY)

C2.1 MODELLING ACROSS BIOLOGICAL SCALES

Thursday 6 July 2023

09:05-09:50

Megan L Matthews (University of Illinois at UrbanaChampaign, United States)

mlmatth2@illinois.edu

Plants have developed complex regulatory strategies to adapt to changes in their environments. As such, they are regulated at multiple levels of biological organisation. Multiscale models that integrate across levels of biological organisation are important to capture and predict emergent properties that are not seen when only modelling individual biological scales. These models can help identify gaps in our current understanding of a biological process and can be used to explore strategies for engineering plants with desired traits. Modelling across these biological scales involves working with a variety of data with different properties. Using transcript and protein abundances, enzyme kinetics, and wood physical and chemical properties, we’ve developed a multiscale model of lignin biosynthesis that spans from gene transcription to lignin and wood traits in Populus trichocarpa. By modelling the multiscale behaviour, we improve our ability to predict how transgenic modifications of lignin genes impact key bioenergy traits.

results in a reduced confidence in the identification of mobile sRNA. Here, we introduce a novel R package,RNAlocate, which integrates the analysis, identification, and visualisation of sRNA movement between genotypes, starting from RNA sequencing experiments performed with the grafting of two genotypes. Most importantly, we show that the package is versatile across organisms and experimental designs, as well as, allowing targeted analysis of sRNA classes across multiple species.

C2.4 DIGITTALLY- A CONVENIENT SYSTEM TO MAKE SMART DECISIONS ABOUT DROSOPHILA BIG DATA

Thursday 6 July 2023 10:10-10:30

Mehwish Akram (University of Glasgow, United Kingdom), Andrew Gillen (University of Glasgow, United Kingdom), Shannon Keenan (University of Glasgow, United Kingdom), Julian A. Dow (University of Glasgow, United Kingdom), Shireen A. Davies (University of Glasgow, United Kingdom)

mehwish.akram@glasgow.ac.uk

Thursday 6 July 2023

09:50-10:10

Katie Jeynes-Cupper (University of Birmingham, United Kingdom), Marco Catoni (University of Birmingham, United Kingdom)

kej031@student.bham.ac.uk

In plants, systemic signalling is an elaborate molecular system that allows plants to coordinate development by integrating and transmitting information perceived from the environment to distant organs. Small RNAs (sRNAs) play an important role in long-distance signalling, where they are produced in one tissue and transported by the vascular system into recipient organs. Plant grafting systems have been used to study sRNA mobility and their implications on molecular mechanisms resulting in variation in plant physiology. These implications include changes to gene expression through post-transcriptional gene silencing via mRNA degradation, or alterations to DNA methylation patterns via the RNA-directed DNA methylation pathway. However, genomic study of sRNA movement between genotypes in a graft system lacks a standardized approach and an absence of resources to support the workflow or the presence of a streamline analysis pipeline. This

Drosophila has a deep and vast research base in the field of life science. While this wealth of data intuitively permits a variety of research, it also presents a new problem – the integration of multiple datasets, each of which contains vastly different information. To provide a flexible solution to this issue, we have designed a system of multi-dataset interrogation, identifying genes of interest in a user-defined subset of Drosophila tissues. Using this computational meta-analysis framework, we were able to identify sets of genes that showed strongly enriched expression in the four key alimentary epithelia (salivary gland, midgut, tubules, and hindgut). The hypothesis independent approach led to the functional analysis of a novel couple of Tetraspanin (Tsp) 29Fa/b genes in the core Drosophila epitheliome.

C2.3 PHILOSOPHICAL PERSPECTIVES ON DATA-INTENSIVE PEST-PLANT INTERACTION STUDIES ACROSS THE LAB AND THE FIELD

Thursday 6 July 2023 11:00-11:45

Emma Cavazzoni (Exeter University, United Kingdom), Sabina Leonelli (Exeter University, United Kingdom)

Ec788@exeter.ac.uk

C2.2 MOBILERNA: LOCATING MOBILE RNAS IN CROP GRAFTING

This talk interrogates the impact of Big Data on biological discovery by focusing on the differences between data collection technologies inspired by research in the lab and in the field, respectively. It is wellestablished, in philosophy of science as well as biological research, that the assumptions and pragmatic requirements embodied by model systems used for laboratory work have a strong bearing on the ways in which instruments and methods are developed, and therefore on what data are collected on these systems, and how (Leonelli 2016). It is also well-established that findings obtained on laboratory model systems do not necessarily or easily map on findings obtained in the field, since the characteristics of the former are adapted to life under controlled conditions (Ankeny and Leonelli 2020). Taking the example of research on pest-plant interactions, and particularly on the impact of the brown marmorated stink bug Halyomorpha halys on pear trees and fruits, we argue that the differences in how model systems (in this case, pears and H. halys) are treated in lab and field is reflected in the technologies developed to generate relevant data; and that this in turn creates severe challenges when attempting to compare and integrate these heterogeneous data. We ground our reflection on a collaboration with the HALY-ID study in Northern Italy, whose goal is to generate and deploy a high volume of data collected through remote sensing in the field as well as laboratory analysis to limit the damage inflicted by Halyomorpha halys to fruit production.

C2.5 DYNAMICS-INFORMED CHARACTERIZATION OF MOLECULAR, CELLULAR, AND POPULATION MECHANISMS

Thursday 6 July 2023 11:45-12:30

Jose M. G. Vilar (University of the Basque Country, Spain)

j.vilar@ikerbasque.org

A fundamental question in understanding biological systems is how to translate the quantification of their observed behavior into the characterization of the underlying mechanisms. This process is challenged at multiple levels by diverse intrinsic and extrinsic factors, ranging from unavoidable fluctuations that mask the reporter signals to the inherent system heterogeneity to multiple sequential responses mixed over time. I will discuss the approaches we have used to overcome these challenges in the characterization of the molecular interactions underlying the disaggregation of pathological amyloid structures, the cellular processes involved in sustaining gene regulation through the cell cycle, and the determinants of regime changes in infection transmission. We rely on the integration of multiple approaches, including molecular mechanics, dynamical systems, stochastic processes, and machine learning.

C3 - CELL CYCLE CONTROL IN NON-MAMMALIAN SYSTEMS

ORGANISED BY: JIM MURRAY (CARDIFF UNIVERSITY)

C3.1 CENTROSOMES AND THE HIDDEN RHYTHMS OF CELLS

Wednesday 5 July 2023 09:30

Jordan Raff (University of Oxford, United Kingdom)

jordan.raff@path.ox.ac.uk

Most eukaryotic cells are born with a single centrosome that plays an important part in many aspects of cellular organization. Centrosomes are an excellent model for studying organelle biogenesis as, just like a cell’s DNA, the centrosome must duplicate precisely once during each cell cycle to ensure that a faithful copy is passed on to each daughter cell. In the early Drosophila embryo, hundreds of centrosomes are synchronously assembled every few minutes as the embryos rapidly progress through repeated rounds of S- and M-phase without intervening gap phases. By combining live-cell imaging, computational analyses and mathematical modelling we have been generating quantitative descriptions of the kinetics of centriole and centrosome assembly. We find that local oscillations in the levels of the enzymes that initiate centrosome assembly are normally entrained by the embryonic CDK/Cyclin cell cycle oscillator (CCO) to help ensure that centrosomes assemble at the right time and place, and then grow to the right size. Surprisingly, the local levels of these enzymes can oscillate even when the CCO is perturbed, allowing centrosomes to continue through repeated rounds of assembly. These studies provide new insights into how cells might regulate and coordinate the biogenesis of their many organelles.

C3.2 COMPARISON OF REPLICATION TIMING PROGRAMS IN MAIZE AND SORGHUM

Wednesday 5 July 2023 10:00

Linda Hanley-Bowdoin (North Carolina State University, United States), Emily E. Wear (North Carolina State University, United States), Emily M. Wheeler (North Carolina State University, United States), Leigh Mickelson-Yiung (North Carolina State University, United States), H. Sara Akram (Florida State University, United States), Zachary M. Turpin (Florida State University, United States), Lorenzo Concia (Texas Advanced Computing Center, United States), Hank Bass (Florida State University, United States), William F. Thompson (North Carolina State University, United States)

linda_hanley-bowdoin@ncsu.edu

During the cell cycle, DNA replication is a highly regulated process that integrates the time that a genome segment replicates in S phase with its transcriptional activity, chromatin structure, and epigenetic state. In plants, DNA replication in meristems gives rise to leaves, roots and inflorescences. Understanding how plant replication timing programs are established is important because chromosomal events that occur early in development are connected to DNA replication and potentially impact gene expression programs and phenotypic traits throughout the plant life cycle. We used 5-ethynyl-2'-deoxyuridine (EdU) labeling and flow cytometry in combination with deconvolution microscopy and high throughput sequencing to characterize the spatiotemporal patterns of DNA replication across the maize B73 genome in root tip meristems. Comparison of cells in a mitotic cell cycle and those in a developmentally programmed endocycle uncovered replication timing differences at centromeres. We are now taking advantage of the high level of genetic diversity of maize and the evolutionary connection between maize and sorghum to examine the relationship between replication timing programs and genome structure. Comparative analysis of DNA replication programs in maize and sorghum will provide insight into how genome duplication and transposon-mediated genome expansion impact DNA replication programs. Comparison of two interfertile maize inbred lines (temperate B73 and tropical NC350) will reveal how replication timing is affected by genomic structural variation within a plant species. These studies will define regions in which replication is altered in the three genotypes, and how such alterations are related to transcription rates, TE composition, and chromatin accessibility.

C3.3 MITOTIC CELL DIVISION IN PHYSCOMITRELLA

Wednesday 5 July 2023 11:00

Gohta Goshima (Nagoya University, Japan)

goshima@bio.nagoya-u.ac.jp

Unlike animal somatic cells, plant cells lack centrosomes; the assembly and positioning of the mitotic spindle rely exclusively on acentrosomal microtubules. The phragmoplast is another plant-specific structure required for cell division, and its formation and dynamics regulation are also carried out by acentrosomal microtubules and the associated proteins. We have studied the mechanisms of spindle/phragmoplast formation and their dynamics using the moss Physcomitrella as a model plant. This presentation will introduce the latest findings on the mechanisms of spindle formation, orientation, and positioning during asymmetric cell division in Physcomitrella. In addition, how the phragmoplast directs cell plate formation to the appropriate plane will be discussed.

C3.4 ENTRY INTO THE CELL CYCLE IN GREEN ALGAE

Wednesday 5 July 2023 11:30

Puthur Vijayan Sijil (Institute of Microbiology Czech Academy of Sciences, Czech Republic), Kateřina Bišová (Institute of Microbiology Czech Academy of Sciences, Czech Republic)

sijil@alga.cz

Green algae dividing by multiple fission can be naturally synchronised by alternating light/dark periods, resulting in highly synchronised cultures. This makes them a unique and highly reliable model for cell cycle studies. Algae can divide into 2, 4, 8, 16 or even more daughter cells within a single cell cycle. This is achieved by a correlation between cell cycle entry and cell growth. Thus, cell cycle progression is dependent on light and temperature, key factors for autotrophic growth. In autotrophic algae, a single chloroplast is responsible for most of the cell growth in terms of volume, proteins, and energy reserves, suggesting that cell cycle entry could be mechanistically underpinned by signalling and correlation between the nucleus and the chloroplast. Here we examined a unique set of experiments using different combinations of light and temperature. The two parameters differ in their effect on cell cycle entry. The amount of light only affects the timing of cell cycle entry, while changes in temperature affect both the timing of cell cycle entry and critical cell size. By comparing gene expression in the datasets, we identified genes specifically related to cell cycle entry, as well as genes that are "light-inducible" and "temperature-responsive".

C3.5 TIME-RESOLVED PHOSPHO-PROTEOMICS OF THE MEIOTIC DIVISIONS

Wednesday 5 July 2023 11:45

Adele L. Marston (University of Edinburgh, United Kingdom), Lori Koch (University of Edinburgh, United Kingdom), Christos Spanos (University of Edinburgh, United Kingdom), Van Kelly (University of Edinburgh, United Kingdom), Tony Ly (University of Dundee, United Kingdom)

adele.marston@ed.ac.uk

The cell cycle is created by a system of controlled kinase and phosphatase activity which allows for the ordered execution of essential events such as DNA replication and chromosome segregation. To generate haploid gametes for sexual reproduction, the meiotic cell cycle includes two sequential rounds of chromosome segregation without an intervening S phase. Relatively little is known about how this unique cell cycle pattern is established. To uncover the signal transduction pathways that establish the two nuclear divisions, we performed quantitative phospho-proteomics with samples of budding yeast undergoing the meiotic divisions highly synchronously. Our data support previous observations such as two sequential rounds of Cdc14 phosphatase activation in anaphase I and anaphase II. To disentangle the pathways required for two meiotic divisions, we additionally performed quantitative phospho-proteomics on equivalent time-course samples from cells lacking the meiosis-specific kinase regulator, Spo13, which undergo only a single meiotic division. Our findings define the waves of phosphorylation that drive the meiotic cell cycle and provide insight into how a meiosis-specific kinase regulator re-models cell cycle controls.

C3.6 THE WHERE AND WHEN OF MITOTIC MICROTUBULE NUCLEATION

Wednesday 5 July 2023

15:00

James G Wakefield (University of Exeter, United Kingdom)

j.g.wakefield@exeter.ac.uk

The accurate alignment and segregation of duplicated chromosomes requires the formation of a robust microtubule-based spindle apparatus. Entry into mitosis precipitates a cascade of signalling events which result in the activation of pathways responsible for nucleating, organising and regulating distinct populations of microtubules to form the spindle. In animal cells, the centrosomes have been characterised as the main microtubule nucleating and organising centres. However, research over the last 15 years has demonstrated that the phenomenon of branched microtubule nucleation – where daughter microtubules are nucleated from mother microtubulesgenerates the bulk required for spindle formation in a variety of cells. Branched microtubule nucleation relies on the recruitment of the microtubule templator, the gamma-Tubulin Ring Complex (γ-TuRC), to pre-existing microtubules via a conserved octameric protein complex, Augmin. In this talk, I will describe recent research undertaken by a member of our lab, Ammarah Tariq, reconstituting branched microtubule nucleation using the Drosophila embryo, and elucidating how regulation of the Augmin complex through phosphorylation maintains the centrosome as the dominant site of mitotic microtubule nucleation.

C3.7 MITOTIC PP2A-B56PAR1 PHOSPHATASE CONTROL IN FISSION YEAST

Wednesday 5 July 2023 15:30

Lenka Halova (Cancer Research UK Manchester Institute, United Kingdom), D.L. Smith (Cancer Research UK Manchester Institute, United Kingdom), Iain Hagan (Cancer Research UK Manchester Institute, United Kingdom)

Lenka.Pribylova@cruk.manchester.ac.uk

Mitosis is driven by the acquisition of reversible phosphorylation on a large number of proteins to drive genome segregation. The phosphatases PP1 and PP2A are responsible for the majority of Ser/Thr dephosphorylations in the cell. Indeed, PP1, PP2A-B55 and PP2A-B56 provide the majority of dephosphorylation activities in mitotic control. While bulk activities of these phosphatases are inhibited to enable phosphate to accumulate on mitotic substrates, localized pools of PP1 and PP2A-B56 are dynamically modulated during mitosis to regulate local events. PP1 is largely monomeric, while PP2A holoenzymes combine a common catalytic (C) and a scaffold (A) subunits with one of four PP2A isotype specific regulatory (B) subunits. It is these regulatory subunits that determine the phosphatase specificity of each PP2A enzyme. Our group previously described a mitotic phosphatase relay in fission yeast in which autocatalytic PP1Dis2 reactivation at the metaphase/anaphase transition supports PP2A-B55Pab1 reactivation, before this PP2A-B55 enables PP1Dis2 to reactivate PP2A-B56Par1 . To dissect the molecular basis of this relay we have now mapped PP1Dis2 -dependent sites of phosphorylation on B56Par1 . Dynamic control of phosphorylation status at these sites is required for both the control of timing of mitotic commitment and for ensuring the fidelity of mitotic progression once cells are in mitosis. The major mitotic kinase Cdk1-

Cyclin B and PP1Dis2 directly phosphorylate/dephosphorylate these sites in vitro. We are currently determining how this phosphorylation impacts upon the activity of the PP2A-B56 enzyme complex. The sites we study reside within a region of the molecule recently proposed to modulate enzymatic activity.

C3.8 CONTROL OF THE SPINDLE ASSEMBLY CHECKPOINT IN ARABIDOPSIS

Wednesday 5 July 2023 15:45

Arp Schnittger (University of Hamburg, Germany), Kostas Lampou (University of Hamburg, Germany), Franziska Böwer (University of Hamburg, Germany), Shinichiro Komaki (Nara Institute of Science and Technology, Japan)

arp.schnittger@uni-hamburg.de

The spindle assembly checkpoint (SAC) is a surveillance mechanism active during metaphase to prevent aneuploidy. The SAC is especially important during meiosis to maintain genome stability over generations and sustain fertility. However, despite its crucial role for reproduction and breeding, little is known about the plant meiotic SAC. Here, we present a cytological and functional framework of the SAC in male meiocytes of Arabidopsis thaliana. Using live-cell imaging, we have dissected the temporal association of SAC components with the kinetochore and have identified important regulators of SAC assembly and disassembly at kinetochores. Importantly, we find that the meiotic SAC is only active for a limited time under severe microtubule destabilizing conditions leading to the hypothesis that the relaxed nature of the meiotic SAC is a gateway to polyploidization and hence might contribute to genome evolution in plants.

C3.9 CYCD MEDIATED MORPHOGENESIS IN HIGHER PLANTS

Wednesday 5 July 2023 16:15

Walter Dewitte (School of Biosciences Cardiff University, United Kingdom), Joanne Kilby (School of Biosciences Cardiff University, United Kingdom), Ondrej Novak (Laboratory of Growth Regulators. Palace University Olomouc, Czech Republic), Alvin Szeto (School of Biosciences Cardiff University, United Kingdom), Emily Sornay (School of Biosciences Cardiff University, United Kingdom), Angharad Jones (School of Biosciences Cardiff University, United Kingdom), Jim Murray (School of Biosciences Cardiff University, United Kingdom)

DewitteW@cardiff.ac.uk

D-type cyclins promote cell division in higher plants. D-type cyclins form active kinases with CDKA;1 that inactivate the Retinoblastoma Related inhibitor and activate other cell cycle targets. As such progressive loss of function of multiple CYCD genes reduces the number of cells in organs, and this is partially compensated by increased cell expansion. In addition, loss of function of D -type cyclins impaired cytokinin induced shoot regeneration but enables root formation in tissue culture and confers subtle embryonic defects, effects which are not obviously

linked to cell cycle defects. Cycd3 mutant root cells display a reduced polarisation of an auxin efflux carrier, an effect readily rescued by CYCD3 induction. Consequently, cycd3 mutant roots accumulate auxin and this is associated with changes in the expression of auxin and cytokinin signalling reporters in the different root tissues. Moreover, induction of CYCD3 triggers cytokinin signalling in the cambium but reduces cytokinin signalling in the root cap, an effect which can be mimicked by treatments with polar transportable auxin. These observations suggest an interaction between D-type cyclins, cytokinin signalling and auxin transport and the different potential mechanisms for these interactions will be discussed. In summary, this indicates a possible role for D type cyclins acting as a molecular link between cell division and morphogenesis.

POSTER SESSION

Wednesday 5 July 2023 17:15-19:15

C1.10 CYCD EXPRESSION MEDIATED CELL PRODUCTION AND HORMONE DISTRIBUTION IN ARABIDOPSIS THALIANA

Wednesday 5 July 2023 POSTER SESSION

Joanne Kilby (Cardiff University, United Kingdom), Angharad R Jones (Cardiff University, United Kingdom), Walter Dewitte (Cardiff University, United Kingdom), Jim AH Murray (Cardiff University, United Kingdom) kilbyj@cardiff.ac.uk

In many eukaryotes, D-type cyclins promote the G1/S transition of the mitotic cell cycle through the activation of CDKA;1, in response to both external and internal environmental and developmental signals.

Here, we studied the effects of progressive loss of D-type function on growth and development of Arabidopsis thaliana. We analysed higher order cycd mutants in which the function of up to six D-type cyclins was removed. Cell numbers in organs were reduced in a CYCD dose dependent manner, with cell areas increasing to compensate organ size. However, once a threshold is met the cell size can no longer compensate for the reduction in cell number, leading to smaller lateral organs, embryos with reduced cell numbers and subtle patterning defects in flowers. RNA seq based transcriptomics revealed modulation of the expression of other factors involved in the G1/S switch upon loss of CYCD function, indicating that the G1/S network is highly dynamic.

In addition, in seedlings of higher order cycd mutants, we see abnormal phenotypes that are reminiscent of mutant seedlings with impaired auxin flux or signalling. These higher order cycd mutants display alterations in auxin and cytokinin signalling reporter expression at the root cap, and defects in the cellular polarisation of auxin efflux carriers, a defect which can be rescued by an inducible CYCD3;1 construct. These observations suggest a possible role for D-type cyclins in maintaining proper hormone distribution besides stimulating cell division, both required for organ patterning.

C3.16 BEYOND CHROMATIN: HISTONE H3 AS A CELL CYCLE REGULATOR IN DROSOPHILA EMBRYOGENESIS

Thursday 6 July 2023 09:00-09:30

Amanda Amodeo (Dartmouth College, Unites States)

Amanda.Amodeo@dartmouth.edu

Cells must maintain a typical cell size for proper physiological functioning. Cell size control requires that division be balanced by growth. An important open question is how cells measure their size to maintain this balance. The early cleavage divisions of the Drosophila embryo are an excellent model system for studying this relationship since the newly fertilized egg is an unusually large cell with unusually rapid cell cycles. To reduce cell size and increase cell number, the first hours of Drosophila development are dominated by a series of rapid, reductive, syncytial nuclear divisions. These divisions lack both growth phases and bulk of zygotic transcription and therefore are driven by maternally provided products. Once enough nuclei are made the cell cycle pauses to allow cellularization of the syncytium during a developmental transition known as the mid-blastula transition (MBT). The final cell size is determined by the number of nuclei that the embryo has generated by cellularization. Strikingly, the ratio of nuclei to cytoplasm (N/C ratio), which directly correlates to final cell size, determines when the cell cycle stops and cellularization occurs. We have identified histones, particularly histones of the H3 family, as critical players in this process. H3 interacts with the DNA-damage checkpoint kinase, Chk1, to prevent cell cycle slowing before a sufficient N/C ratio has been met. Ongoing work in the lab seeks to understand how H3 nuclear concentrations are tied to the local N/C ratio and the importance of H3 subcellular localization in cell cycle progression.

C3.11 POLYPLOID CELL CYCLES IN ORGAN DEVELOPMENT AND INJURY REPAIR

Thursday 6 July 2023 09:30

Don Fox (Duke University, United States), Archan Chakraborty (Duke University, United States), Jessica Sawyer (Duke University, United States), Ruth Montague (Duke University, United States)

don.fox@duke.edu

Cell cycles that complete DNA replication but do not complete cell division lead to whole genome duplication. The result of such genome duplication is a polyploid cell. Polyploid cells are common throughout evolution and have been found in at least 9 of 11 mammalian organ systems. Purposes of such polyploid cells remain largely mysterious. To begin to understand purposes of polyploidy in tissues, we developed several accessibleDrosophilatissue models. The developingDrosophilaheart and hindgut papillae are examples of tissues that depend on precise control of cellular ploidy level in specific locations for proper organ morphogenesis. These studies reveal that local control of DNA copy number can program tissue form and function. In contrast, the developing wing is an example of a tissue that adapts to altered ploidy level. However, increasing the ploidy of wing progenitors leads to a greater dependency on the mitotic spindle checkpoint. These studies highlight distinct molecular dependencies of

polyploid cells. Finally, the injured hindgut pylorus relies on polyploidy and not cell division to regenerate. This ploidy-driven repair program enables organ regeneration without compromising tissue barriers. Collectively, our work is revealing distinct biology of polyploidy that drives critical organ developmental and injury repair events.

C3.12 CELL CYCLE AND CELL SIZE CONTROL IN PLANTS

Thursday 6 July 2023 10:00

Angharad R Jones (Cardiff University, United Kingdom), Daniel Williamson (University of Nottingham, United Kingdom), William Tasker-Brown (Cardiff University, United Kingdom), Emma Williams (Cardiff University, United Kingdom), James Murray (Cardiff University, United Kingdom), Leah Band (University of Nottingham, United Kingdom)

jonesar14@cardiff.ac.uk

Cell size is known to affect the function of both individual cells and tissues, but how cell size is regulated is poorly understood. In plants, the size of mitotically active cells has been shown to be an emergent property of cell growth and cell division that can be created as a natural consequence of cell growth on the concentration of cell cycle regulatory proteins. We are using a systems approach to better understand the mechanisms by which cell size information is integrated into cell cycle progression. Our theoretical work shows that interplay between sizedependent and size-independent cell cycle regulators is sufficient to create switch like behaviours that can be triggered by cell growth at both the G1/S and G2/M transitions. Although most growth occurs during the G1 phase of the cell cycle, population level simulations indicate that cell size control is required at both checkpoints in order to produce robust cell size control. To understand the G2/M transition better we are experimentally testing cell size dependency of cell cycle regulators at the G2/M transition. Our findings have implications for how developmental and environmental signals are integrated at the cellular level.

C3.13 CENTROMERE ASSEMBLY AND FUNCTION IN DROSOPHILA GERMLINE STEM CELLS.

Thursday 6 July 2023 11:00

Elaine M Dunleavy (University of Galway, Ireland), Antje M Kochendoerfer (University of Galway, Ireland), Rachel S Keegan (University of Galway, Ireland)

elaine.dunleavy@universityofgalway.ie

Stem cells can undergo asymmetric cell division (ACD) giving rise to one new stem cell and one differentiating daughter cell. In Drosophila germline stem cells (GSCs), the centromeric histone CENP-A - CID in flies - is asymmetrically distributed between sister chromatids such that chromosomes that end up in the GSC harbour more CID at centromeres. A model of ‘mitotic drive’ has been proposed in GSCs such that stronger and earlier centromere and kinetochore interactions with microtubules bias sister chromatid segregation. Here we show that in Drosophila males, centromere proteins CID, CAL1 and CENP-C

are asymmetrically distributed in newly divided GSCs and daughter cells in S-phase. We find that CID overexpression, overexpression of CID together with CAL1 or CENP-C depletion disrupts CID asymmetry, with an increased pool of GSCs relative to daughter cells detectable in the niche. This result suggests a shift toward GSC self-renewal rather than differentiation, important for maintaining tissue homeostasis. Overexpression of CAL1 does not disrupt asymmetry, but instead drives germ cell proliferation in the niche. Our results in male GSCs are comparable to female GSCs, indicating that despite differences in signaling, organisation and niche composition, effects of centromere proteins on GSC maintenance are conserved between the sexes.

C3.14 THE CANONICAL E2FS TOGETHER

ARE REQUIRED TO ESTABLISH QUIESCENCE DURING PLANT DEVELOPMENT

Thursday 6 July 2023 11:45

Zoltan Magyar (Institute of Plant Biology Biological Research Centre, Hungary)

magyar.zoltan@brc.hu

Maintaining stable and transient quiescence in differentiated and stem cells, respectively, requires repression of the cell cycle. The plant RETINOBLASTOMA-RELATED (RBR) has been implicated in stem cell maintenance, presumably by forming repressor complexes with E2F transcription factors. Surprisingly we find that mutations in all three canonical E2Fs do not compromise the cell cycle, but similarly to RBR silencing, result in overproliferation. Contrary to the growth arrest upon RBR silencing, when exit from proliferation to differentiation is inhibited, the e2fabc mutant develops enlarged organs with supernumerary stem and differentiated cells as the quiescence is compromised. While E2F, RBR and the M-phase regulatory MYB3Rs are part of the DREAM repressor complexes, and recruited to overlapping groups of targets, they regulate distinct sets of genes. Only the loss of E2Fs but not the MYB3Rs interferes with quiescence, which might be due to the ability of E2Fs to control both G1-S and some key G2-M targets. We conclude that collectively the three canonical E2Fs in complex with RBR have central roles in establishing cellular quiescence during organ development, leading to enhanced plant growth.

C3.15 TEMPORAL REGULATION OF PROTEIN DEGRADATION IRREVERSIBLE MEIOTIC EXIT

Thursday 6 July 2023 12:00

Soni Lacefield (Geisel School of Medicine at Dartmouth, United States), Anna Zike (Indiana University, United States), Gisela Cairo (Geisel School of Medicine at Dartmouth, United States), Somdutta Paul (Geisel School of Medicine at Dartmouth, United States), Sima Setayeshgar (Indiana University, United States)

Soni.Lacefield@Dartmouth.edu

The complex cell division process of meiosis ensures the formation of haploid gametes through two rounds of chromosome segregation after one round of DNA replication. How cells limit meiosis to two and

only two divisions is poorly understood. We previously found that autophagy is needed for meiotic exit in budding yeast. Inhibition of autophagy during meiosis results in meiotic exit failure; instead, cells undergo additional rounds of chromosome segregation. Autophagy degrades the RNA-binding protein Rim4 in meiosis II, which forms aggregated fibrils that bind mRNAs and prevent their translation prior to its degradation. Several mRNAs bound by Rim4 encode regulators of meiotic exit, including the cyclin Clb3 and the meiosis-specific APC/C co-activator Ama1, which targets proteins for degradation. Inhibition of autophagy prevents Clb3 and Ama1 accumulation.

We sought to obtain a systems-level understanding of the meiotic termination network. We built a parsimonious mathematical model simulating meiotic exit. Using modeling and experiments, we describe the dynamics of key constituents governing irreversible meiotic exit, notably how autophagy disruption could result in exit failure and continued cell-cycle oscillations. We hypothesize that mRNA binding to Rim4 fibrils allows tight sequestration of the mRNAs until the fibrils are disrupted and degraded for switch-like mRNA release. Guided by our modeling, we performed additional experiments to define the minimal meiotic termination network. These results are consistent with a role of Rim4 in protecting mRNAs from degradation until Rim4 is degraded, and a surge in Ama1 production and concomitant increase in APC/CAma1 activity allows irreversible meiotic exit.

WITH RETINOBLASTOMA-RELATED

PLANT BIOLOGY ABSTRACTS

P1 - IMPROVING CROP NUTRIENT STATUS: DISCOVERY, INNOVATION & TRANSLATION

ORGANISED BY: CHRISTINE FOYER (UNIVERSITY OF BIRMINGHAM), DEREK STEWART (THE JAMES HUTTON INSTITUTE), RAUL HUERTAS (THE JAMES HUTTON INSTITUTE), ROBERT HANCOCK (THE JAMES HUTTON INSTITUTE)

P1.1 DELIVERING LOW-GLYCAEMIC WHITE BREAD USING HIGH-AMYLOSE WHEAT FLOUR

Tuesday 4 July 2023 09:00

Brittany Hazard (Quadram Institute, United Kingdom)

Brittany.Hazard@quadram.ac.uk

White bread made with high-amylose wheat flour has potential to be low-glycaemic compared to bread made with conventional wheat flour, however, the effects of using high-amylose wheat flour on starch characteristics of white bread and its glycaemic response in people still require investigation. In this study we report the impact of a high-amylose starch branching enzyme II (sbeII) mutant wheat flour on starch characteristics (including in vitro starch digestibility) of white bread made with different processing methods and stored in different conditions. We also report the impact of breads made with high-amylosesbeIIwheat flour on postprandial glycaemia in vivo compared to an isoglucidic wild-type control in two acute dietary intervention studies. Overall, we found that white bread made with high-amylosesbeIIwheat flour leads to lower starch digestibility in vitro, and has a tendency towards lower glycaemic responses in vivo. These results will greatly support the rational design of new wheat varieties using mutant wheat flours to deliver healthier bread with lower glycaemic impact.

P1.2 MODIFICATION OF AMYLOPLAST

Tuesday 4 July 2023 09:30

Lara Esch (John Innes Centre, United Kingdom),

Qi Yang Ngai (John Innes Centre, United Kingdom),

Elaine J Barclay (John Innes Centre, United Kingdom),

Rose McNelly (John Innes Centre, United Kingdom),

Sadiye Hayta (John Innes Centre, United Kingdom),

Mark A Smedley (John Innes Centre, United Kingdom),

Alison M Smith (John Innes Centre, United Kingdom), David Seung (John Innes Centre, United Kingdom)

lara.esch@jic.ac.uk

Starch granule morphology is a major factor determining functional and nutritional properties of starch. Here, we reveal an important role of amyloplast structure on morphogenesis of starch granules in wheat endosperm. Wheat amyloplasts contain large lenticular A-type granules and small spherical B-type granules. We isolated a mutant in durum wheat defective in the plastid division protein PARC6, which had increased plastid size in both leaves and endosperm. The A- and B-type granules of mature grain were significantly larger in the mutant compared to the wild type, and the surface morphology of A-type granules was highly aberrant. This striking feature was already evident at early stages of grain development, where mutant granule size was still indistinguishable from the wild-type. The changes in granule morphology occurred without alterations in starch polymer structure and composition. Despite the large changes in plastid size and starch granule morphology, the growth, development and photosynthetic efficiency, grain size, number and starch content was not affected in theTtparc6mutants. Interestingly, a durum wheat mutant in the PARC6 paralog, ARC6, did not increase plastid or starch granule size. We suggest this is due to the ability of PARC6 to complement disrupted ARC6 function, since wheat PARC6 interacts with both wheat PDV1 paralogs as well as PDV2, the outer plastid envelope protein that typically interacts with ARC6 to promote plastid division. We propose that modification of wheat amyloplast architecture to increase plastid compartment size and stromal volume results in larger starch granule sizes and numbers per amyloplast.

SIZE IN WHEAT THROUGH MUTATION OF PARC6 AFFECTS STARCH GRANULE MORPHOLOGY

P1.3 THE ROLE OF NAC TRANSCRIPTION FACTORS IN LEAF SENESCENCE AND GRAIN PROTEIN CONTENT

Catherine E B Evans (John Innes Centre, United Kingdom), Ruth Bryant (RAGT Seeds Ltd, United Kingdom), Juliet Coates (University of Birmingham, United Kingdom), Philippa Borrill (John Innes Centre, United Kingdom)

Catherine.Evans@jic.ac.uk

Wheat provides 20% of calories in global diets. Improving wheat grain protein content would benefit both bread quality and nutrition. Producing high-protein, high-yield wheat is impeded by a genetic trade-off between protein content and yield. The timing of leaf senescence may mediate this trade-off: nitrogen remobilization from senescing leaves supplies 65-90% of grain protein, but early senescence curtails photosynthesis, decreasing yield. NAC family transcription factors play key roles in regulating leaf senescence in Arabidopsis and rice. In wheat, the NAC transcription factor NAM-1 promotes higher grain protein content via earlier senescence and increased nitrogen remobilization to the grain. However, few other senescence regulators have been thoroughly characterised in wheat.

We explored the role of other NAC transcription factors in the timing of wheat leaf senescence and grain protein content. We selected candidate NAC genes upregulated in an RNA-seq timecourse of early flag leaf senescence. To test whether these NAC genes were necessary and sufficient to promote earlier senescence, we developed lines with loss-of-function mutations and overexpressed the NAC genes in wheat. Preliminary results indicate that for one candidate NAC, loss-of-function delays onset of leaf senescence, while overexpression may promote leaf senescence. Protein content was unaffected.

We are currently working on identifying the direct downstream targets of senescence-associated NAC transcription factors using DAPseq. Piecing together the network of transcription factors regulating leaf senescence could help us understand the trade-off between grain protein content and yield, and reveal new targets for wheat breeding.

P1.4 PROFILING THE MRNA AND MICRORNA TRANSCRIPTOME OF DIPLOID POTATO TO UNDERSTAND THE REGULATION OF STARCH METABOLISM

Tuesday 4 July 2023 10:15

Thomas E. G. Navarro (John Innes Centre, United Kingdom), David Seung (John Innes Centre, United Kingdom), Burkhard Steuernagel (John Innes Centre, United Kingdom), Benoit Bely (Tropic, United Kingdom), Luke Braidwood (Tropic, United Kingdom)

thomas.navarro@jic.ac.uk

Potatoes are among the most important food crops globally and genetic approaches to improve nutritional and post-harvest quality are of great interest. However, in the common tetraploid potato, the highly heterozygous genome, inbreeding depression, and long generation cycles pose challenges for genetic improvement. Inbred diploid lines are emerging as a promising breeding platform for generating highperforming hybrid potato and are particularly suitable for gene-editing technologies as they provide a means to cross-out editing transgenes as well as a route to introduce target traits into commercial germplasm. However, due to their novelty, metabolic pathways relevant to key quality traits in the tuber have not yet been studied in these lines. Starch is the major carbohydrate in potatoes. It is produced during tuber development and is partially degraded post-harvest during cold storage. To understand the regulation of these processes in diploid

potato, we generated an mRNA and microRNA (miRNA) transcriptome dataset using RNA sequencing. We grew a diploid potato research line in the glasshouse until tuber maturation and harvesting, and then kept the tubers at low temperatures to simulate cold storage. We sampled leaves and developing tubers at three different stages of development, as well as two stages of cold storage. By analysing and comparing gene expression patterns, we are developing a broad understanding of the genes that mediate key processes of starch biosynthesis and degradation in different tissues, as well as the role of miRNAs in gene regulation in potato tubers.

P1.5 PLANT CELL FACTORIES FOR INDUSTRIAL

AND NUTRITIONAL CAROTENOIDSPAUL D. FRASER*, MARILISE NOGUERIA, JULIANA

ALMEIDA, MARGIT DRAPAL, HARRIET

M. BERRY, PETER M. BRAMLEY, LAURA

PEREZ-FONS AND EUGENIA M. A. ENFISSI. DEPARTMENT OF BIOLOGICAL SCIENCES, ROYAL HOLLOWAY

UNIVERSITY OF LONDON, EGHAM HILL, EGHAM, SURREY, TW20 OEX.UK.

Tuesday 4 July 2023 13:30

Paul D Fraser (Royal Holloway University of London, United Kingdom)

p.fraser@rhul.ac.uk

Chemical refining is a highly efficient process that has driven industrialisation and globalisation. Carotenoid production using chemical synthesis has traditionally been the method of choice. However, dwindling fuel reserves and climatic fluctuation, are now imposing key societal and economic challenges to health and welfare provision, agriculture, manufacturing, and energy. This has resulted in the development of sustainable production platforms for carotenoids. At scale plants are one of the best biobased modes of production. In this presentation the development of Solanaceae crops, particularly tomato for the production of the carotenoid’s lycopene, beta-carotene and xanthophylls will be described using both metabolic engineering and introgression approaches from natural variation. Ketocarotenoids will be of particular focus showing industrial feasibility in aquaculture and as poultry feeds will be demonstrated. Fundamentally, the multiomic characterisation of these varieties has illustrated the metabolic re-programming required to obtain high level production. In addition, the sequestration mechanisms available to store carotenoids elucidated through multiplex CRISPR approaches to elucidate the modification of plastids, plastoglobuli formation and esterification will be described.

P1.6 THE IDENTIFICATION AND CHARACTERISATION OF NUTRIENT DENSE CUCURBITACEOUS SPECIES

Tuesday 4 July 2023 14:00

Katharina Schmidt (Royal Holloway University of London, United Kingdom), Simon Crawford (Burpee NL BV, Netherlands), Henk Van der Velde (Burpee NL BV, Netherlands), Margit Drapal (School of Biological Science Royal Holloway University of London, United Kingdom),

Eugenia M. A. Enfissi (School of Biological Science Royal Holloway University of London, United Kingdom), Paul D. Fraser (School of Biological Science Royal Holloway University of London, United Kingdom)

Katharina.Schmidt@rhul.ac.uk

Fruits and vegetables are a sources of health promoting phytochemicals including vitamins, antioxidants and minerals. They are associated with a positive health impact and can reduce the risk for several disease states like obesity, and its association with type 2 diabetes and cardiovascular diseases. Many people do not consume the recommended five portions of fruits and vegetables per day. Studies show that home gardening crops can be integrated into the dishes and improve the quality of the diet. Home gardening is one possibility to increase the amount of fruit and vegetables in the diet. This has become particularly relevant with the disruption in the food supply chain caused by the pandemic and conflict in Ukraine.

In the present study a diversity panel of Cucurbitaceae was analysed to identify nutrient dense varieties initially for the home garden market. The aim was to measure health promoting phytochemicals in particular carotenoids, which are known for their health benefits. Cucurbitaceous species analysed included C. pepo, C. moschata, Citrullus lanatus and Cucumis melo with different phenotypes. Varieties with the highest carotenoid content were established for each species and phenotype. The variety with the highest carotenoid content was selected for each species. These varieties were compared to varieties with significantly lower carotenoid content at several developmental stages. Analysis of the different fruit layers highlighted that the highest carotenoid levels were present in the exocarp and the lowest carotenoid levels in the endocarp. Therefore, cucurbits should be eaten with the peel to absorb the maximum carotenoid content.

P1.7 NEW BREEDING TECHNOLOGIES FOR IMPROVEMENT OF FRUIT QUALITY

Tuesday 4 July 2023 14:30

P1.7 EAT YOUR GREENS: DEVELOPING IMPROVED NUTRITION FOR HUMAN HEALTH IN LETTUCE AND WATERCRESS USING MOLECULAR BREEDING APPROACHES

Tuesday 4 July 2023 15:30

Gail Taylor (University of California Davis, United States), Yufei Qian (University of California Davis, United States), Lauren E Hibbert (University of Southampton, United Kingdom), Annabelle Damerum (University of California Davis, United States), Mark A Chapman (University of Southampton, United Kingdom), Daniel J Kliebenstein (University of California Davis, United States), Ivan Simko (USDA Salinas, United States), Maria Truco (University of California Davis, United States), Ella Katz (University of California Davis, United States), Richard W Michelmore (University of California davis, United States)

gtaylor@ucdavis.edu

Leafy greens are consumed around the world, eaten both raw and cooked and provide a key route for the delivery of nutrient dense food and enhanced phytonutrients linked to human health. The lettuce, market alone in California has an annual value close to $3B. Using extensive genetic resources developed in lettuce (Lactuca spp) including bi-parental mapping and GWAS populations, we have identified areas of the lettuce genome linked to provitamin A (carotenoids) and total antioxidant (AO) status. For anti-oxidants this has been further resolved to the high concentrations of polyphenols in lettuce, particularly quercetin, with SNP-genotyping identifying the genomic location from which markers were developed and tested in pre-breeding material. The most nutrient dense leafy green on the planet is watercress (Nasturtium officinale), particularly high in vitamins C and K and calcium and like otherBrassicaceae is a rich source of glucosinolates (GLS). The consumption of GLS is linked to several health benefits. We have developed the first bi-parental mapping population of watercress, collected a diverse wild population, sequenced the genome and are defining the ideotype of this crop for hydroponic, indoor growing systems where we will report out latest results on the genetic basis of enhanced nutrition and future indoor breeding.

a.allan@auckland.ac.nz

New Breeding Technologies (NBTs) use molecular methods to provide step changes in consumer and grower traits. We have used NBTs to turn woody perennials into constantly flowering annuals to speed up breeding and rapidly improve horticultural species. The changes we have made to apple and kiwifruit have produced plants for accelerated genefunction testing, breeding, indoor farming and cultivation as an annual crop. Using these plants, crossing has begun targeting better storage, and higher levels of anthocyanins and carotenoids for future cultivars. However, the question remains of how markets will respond to such fruit. Ideally, the product of NBT techniques have no additional DNA and harbour only new variants of genes which are identical to “natural” variants or alleles already in the environment. In some countries these resulting plants are not regulated or considered as GM. With improvements in nutritional and consumer-centric traits, perhaps attitudes will be more positive than previous plant-based products.

P1.9 DOES PHOTORESPIRATORY FLUX AFFECT NUTRITIONAL VALUES?LESSONS FROM C2 PHOTOSYNTHESIS IN WILD ROCKET (DIPLOTAXIS TENUIFOLIA)

Tuesday 4 July 2023 16:00

Catherine A Walsh (Lancaster University, United Kingdom), Marjorie R Lundgren (Lancaster University, United Kingdom)

c.walsh4@lancaster.ac.uk

Agriculture must rise to the challenges brought on by climate change as variable growing conditions threaten the yields and quality required to nourish an ever increasing global population. Currently, 3.1 billion people across the world suffer from malnutrition, with cases forecast to rise as hidden hunger becomes exasperated with declines in

Andrew C Allan (University of Auckland, New Zealand)

nutritional quality brought on by hot temperatures, drought, and carbon fertilization. Yet exactly how rising atmospheric CO2 concentrations will affect key crops is a question open to conjecture as research so far has shown much variability in nutritive response, according to species type, cultivar, and environment. Curiously, the nutrient rich salad green, wild rocket (Diplotaxis tenuifolia) may show resilience in nutritional stability within its native Mediterranean region despite warm temperatures promoting high rates of photorespiration there. This species is unique among crops for using C2 photosynthesis, a simple carbon concentration mechanism that reclaims CO2 released from photorespiration. Indeed, we hypothesise that exceptional biochemistry underlying C2 photosynthesis will help the crop negate CO2 enrichment and maintain nutritional integrity under warm temperatures. Here we investigate how shifts in photorespiratory flux, as induced across four growth temperature treatments, effect nutritional stability in wild rocket to shed more light on C2 biochemistry.

P1.10 THE CONTROL OF ASCORBATE CONCENTRATION IN PLANTS

Tuesday 4 July 2023 16:30

Nicholas Smirnoff (University of Exeter, United Kingdom), Vera Thole (John Innes Centre, United Kingdom), David Cuitun-Coronado (University of Exeter, United Kingdom), Cathie Martin (John Innes Centre, United Kingdom)

n.smirnoff@exeter.ac.uk

Leafy vegetables and fruit are the main source of ascorbate (vitamin C) in the human diet, so there is an interest in understanding the factors determining its concentration in plants. Recent work indicates an important role for GDP-L-galactose phosphorylase (GGP) in controlling the rate of ascorbate synthesis from the hexose phosphate pool. GGP is generally encoded by two or more paralogous genes (e.g. VTC2and VTC5in Arabidopsis) and expression is controlled transcriptionally (in response to light and developmental cues) and translationally via a highly conserved 5’ upstream open reading frame (uORF). Gene editing of the uOFR in several species causes ascorbate over-accumulation, indicating its role in feedback inhibition of ascorbate biosynthesis. We aim to understand how the uORF controls GGP translationviaa putative conserved peptide. The role of the uOFR is also being investigated in the context of GGPtranscription under different conditions in Arabidopsis leaves using luciferase and GFP reporter constructs along with GGP enzyme assays and 13 C-labelling (to measure ascorbate synthesis and turnover rates). We are trying to establish the relative importance of transcriptional control and translational control of GGPs under different physiological conditions to provide a comprehensive understanding of how ascorbate concentration is controlled in tomato and Arabidopsis. The results to date will be presented.

P1.11 INTERDEPENDENT IRON AND PHOSPHORUS AVAILABILITY CONTROLS PHOTOSYNTHESIS THROUGH RETROGRADE SIGNALING

Wednesday 5 July 2023 09:00

Hatem Rouached (Michigan State University, United States)

rouached@msu.edu

Plants rely on a constant supply of macro- and micronutrients to perform photosynthesis. For example, iron is an important micronutrient for photosynthesis, which is supported by longstanding observations that link iron deficiency and chlorosis. However, in the late 1970s, DeKock et al. (1979) reported the development of chlorotic leaves under high-phosphorus conditions despite replete iron levels, challenging the causal connection between iron concentration and chlorosis. More recently, we showed that iron-induced chlorosis in monocots is phosphorus-dependent, in which plants grown under combined iron and phosphorus deficiency display an intriguing “stay green” phenotype. These observations highlight a gap in our understanding of the interdependent effects of nutrient availability on photosynthesis regulation, and raise the question: how do plants integrate nutrient cues to control photosynthesis? Our results show that iron-induced chlorosis is phosphorus-dependent in both monocots and eudicots. By combining genome-wide gene expression changes and genome-wide association studies (GWAS) with molecular physiology in Arabidopsis thaliana, we identified and validated a signaling pathway involved in the regulation of photosynthesis under combined iron and phosphorus stresses. This newly identified mechanism includes genes coding for chloroplastic (PHT4;4) and nuclear (bZIP58) proteins that prevent the repression of the core set of photosynthesis genes and associated chlorosis under iron and phosphorus deficiency. Furthermore, we provided evidence demonstrating the existence of ROS-mediated chloroplastic retrograde signaling pathway to adapt photosynthesis to nutrient availability.

P1.12 VARIATION IN LOCI ASSOCIATED WITH PHOSPHATE AND AUXIN TRANSPORT IN PHOSPHATE TOLERANT VERSUS SENSITIVE ARABIDOPSIS THALIANA ACCESSIONS

Wednesday 5 July 2023 09:30

Ricarda Jost (La Trobe University, Australia), Changyu Yi (La Trobe University, Australia), Xinchao Wang (National Center for Tea Improvement, China), Damien Callahan (Deakin University, Australia), Alexandre Fournier-Level (The University of Melbourne, Australia), James Whelan (La Trobe University, Australia) r.jost@latrobe.edu.au

Phosphorus is essential for plant growth and reproduction. In soils, levels of plant available phosphate vary greatly across seasons and location. To cope with these boom and bust cycles plants developed complex regulatory feedback loops to sense, acquire and store phosphate. Plants from chronically phosphorus poor habitats, however, constitutively express a phosphate starvation response and have lost the flexibility to downregulate this response when soil phosphate levels are adequat. We explored these differences in the physiological and metabolic response to phosphate supply across a genetically diverse set of Arabidopsis accessions. Across accessions, leaf vacuolar phosphate pools plummeted in response to phosphate withdrawl. Root phosphate pools showed greater variablity, which also translated to greater variation in root architectural responses and leaf anthocyanin accumulation which is a stress indicator. Genome-wide association identified a number of loci associated with organ phosphate. Of note, accessions that more rapidly depleted shoot phosphate pools in response to low phosphate supply lacked one of four tandem-repeat

PHOSPHATE TRANSPORTER1 (PHT1) copies on chromosome 5. Aside from copy-number variation, these sensitive accessions also carry SNPs in the remaining PHT1 copies that may alter the corresponding transporters’ membrane topology and activity. Accessions with reduced phosphate translocation from root to shoot under limiting conditions harbored several SNPs in the PIN-LIKES7 (PILS7) locus – one of these may affect protein phosphorylation of this transporter suggested to control auxin efflux from the endoplasmic reticulum. We will discuss how changes to nuclear auxin levels may impact plant performance under low phosphate supply.

P1.13 BRACHYPODIUM DISTACHYONGENE EXPRESSION IN ASSOCIATION WITH ROOT ANATOMICAL PLASTICITY IN RESPONSE TO AMMONIUM AND NITROGEN APPLICATIONS

Wednesday 5 July 2023 10:00

Hamid Rouina (Forschungszentrum Jülich, Germany), Lukas Schreiber (University of Bonn, Germany), Benjamin Stich (Heinrich-Heine-Universität Düsseldorf, Germany), Tobias Wojciechowski (Forschungszentrum

Jülich, Germany), Robert Koller (Forschungszentrum

Jülich, Germany), Uwe Rascher (Forschungszentrum

Jülich, Germany), Johannes Postma (Forschungszentrum

Jülich, Germany)

h.rouina@fz-juelich.de

Understanding the molecular mechanisms underlying plant adaptation to varying nitrogen sources has important implications for agriculture. In this study, we utilized the grow screen agar system to investigate the transcriptomic response ofBrachypodium distachyonroots to two different nitrogen sources (ammonium and nitrate) across seven concentrations, as well as their impact on root anatomy in three depths. Our findings indicate that plants grown in ammonium had smaller stele and cortex areas compared to those grown in nitrate. Notably, the central meta xylem area was larger in deeper root cross-sections for both ammonium and nitrate. Additionally, the root area decreased with depth in ammonium, while it increased in nitrate. On the other hand, plant roots grown in ammonium were observed to perform aerenchyma and cortical senescence. We observed the upregulation of genes involved in root cortex development, such as BRADI_3g59130, in response to both ammonium and nitrate. In contrast, the LBD37 gene family, which is involved in nitrogen metabolism and root anatomy, was downregulated in response to both nitrogen sources. Additionally, we found that genes encoding cortical cell-delineating proteins were downregulated in response to ammonium, whereas they exhibited a 4-fold increase in expression in the highest nitrate concentration. These proteins play a crucial role in cortical differentiation and maintenance, which is essential for maintaining proper cell boundaries and ensuring optimal functioning of the root system. Our findings suggest that ammonium and nitrate have a significant impact on root structure and trigger distinct transcriptomic pathways, leading to complex hormone and gene expression crosstalk.

P1.14 CELLULAR IRON COMPARTMENTALIZATION MECHANISMS

Wednesday 5 July 2023 11:00

Erin L Connolly (The Pennsylvania State University, United States), Anshika Jain (University of South Carolina, United States), Brendon Juengst (The Pennsylvania State University, United States), Youran Huang (The Pennsylvania State University, United States)

elc18@psu.edu

Fe is an essential nutrient for plants where it plays critical roles in the electron transport chains of photosynthesis and respiration. Our research focuses on the molecular mechanisms of Fe transport between the cytosol and two major Fe sinks in plant cells: chloroplasts and mitochondria. Specifically, we are investigating the roles of organellar ferric chelate reductases (FROs) and mitochondrial Fe transporters (MITs) in Fe and Cu homeostasis in Arabidopsis. In the absence of either FRO3 or MIT1/MIT2, total Fe content of the mitochondria is reduced and the plants exhibit signature Fe deficiency phenotypes. Interestingly, we found that while loss of chloroplast-localized FRO7 does not result in significant remodeling of the transcriptome during Fe sufficiency, loss of FRO3 appears to trigger large-scale changes in the transcriptome including induction of Fe deficiency responses when plants are grown under Fe replete conditions. Additionally, we found that while FRO3 is absolutely essential for seed production during Fe deprivation, loss of MITs leads to embryo lethality. Together, these results suggest that FRO3 and MITs work together during Fe deprivation to reduce and shuttle the ferric iron pools of the IMS to the matrix to meet mitochondrial Fe requirements and that FRO3 is also important for whole plant Fe sensing. In contrast, a second mitochondrially-localized FRO (FRO8) appears to play a role in Fe homeostasis that is distinct from FRO3 and important for Fe mobilization during senescence.

AND LPR2 ARE REQUIRED FOR EFFICIENT IRON TRANSLOCATION IN THE XYLEM OF ARABIDOPSIS THALIANA

Wednesday 5 July 2023 11:30

Fang-Jie Zhao (Nanjing Agricultural University, China), Zhong-Rui Xu (Nanjing Agricultural University, China), Peng Wang (Nanjing Agricultural University, China)

fangjie.zhao@njau.edu.cn

Iron (Fe) deficiency is common in agricultural crops and affects millions of people worldwide. Translocation of Fe in the xylem is a key step for Fe accumulation in the above-ground parts of plants. It is well known that Fe is translocated as Fe(III)-citrate/malate complexes. However, autooxidation of Fe(II) to Fe(III) is slow in the acidic environment of xylem sap, and Fe(III)-citrate/malate complexes formed in the xylem sap are easily photoreduced and unstable under light. Here, we show that two Arabidopsis ferroxidases, LPR1 and LPR2, are required to oxidize Fe(II) and maintain Fe(III)-citrate/malate stability and mobility during xylem translocation. LPR1 and LPR2 are mainly localized in the cell walls of xylem vessels. Knockout of both LPR1 and LPR2 increases the proportion of Fe(II) in the xylem sap, and causes

P1.15 THE FERROXIDASES LPR1

Fe deposition along the vascular bundles especially in the petioles and main veins of leaves. Blocking blue light or decreasing light intensity alleviates Fe deposition along the xylem in the double mutant. The double mutant displays constitutive expression of Fe-deficiency response genes and overaccumulation of Fe in the roots and mature leaves under Fe-sufficient supply, but shows Fe-deficiency chlorosis in the new leaves and inflorescences under low Fe supply, as well as decreased Fe concentration in the seeds. The translocation of 57 Fe along the xylem is impaired in the double mutant. Our study uncovers an essential physiological role of LPR1 and LPR2 and also reveals a new mechanism by which plants maintain Fe mobility during longdistance translocation in the xylem.

P1.16 FERROPTOSIS IN PLANTS: TRIGGERS, PROPOSED MECHANISMS AND REGULATION OF LIPID PEROXIDATION

Wednesday 5 July 2023 12:00

Gabriela C. Pagnussat (Instituto de Investigaciones Biologicas IIB-CONICET University of Mar del Plata, Argentina), Ayelén M. Distéfano (IIB-CONICET-UNMdP, Argentina), Gabriel López (IIB-CONICET-UNMdP, Argentina), Victoria Bauer (IIB-CONICET-UNMdP, Argentina), Juan Roldan (IIB-CONICET-UNMdP, Argentina), Eduardo J. Zabaleta (IIB-CONICET-UNMdP, Argentina), Diego F. Fiol (IIB-CONICET-UNMdP, Argentina)

gpagnussat@mdp.edu.ar

Regulated cell death (RCD) is an essential process that plays key roles during the plant life cycle. Unlike accidental cell death, RCD involves integrated signaling cascades and molecular-mediated mechanisms that are triggered in response to specific exogenous or endogenous stimuli. Although first described in animals, ferroptosis in plants shares all the main core mechanisms observed for ferroptosis in other systems. In response to heat stress (HS), ferroptosis is triggered through GSH depletion, ROS accumulation, and iron-dependent lipid peroxidation. Accumulation of lipid peroxides is observed one h after HS, showing a maximum 2-3 hours after HS, which is prevented by canonical ferroptosis inhibitors. Hydroperoxides accumulation and the cell death in response to HS are not observed in lipoxygenases mutants, indicating that plant ferroptosis relies on specific lipoxygenases activity. In addition, incubation with canonical ferroptosis inhibitors prevents cell death when plants are exposed to otherwise lethal temperatures. As this response is typically observed after exposure to sub-lethal high temperatures, a process called acclimation or priming, we studied the response of plants exposed to ferroptosis inhibitors as an approach to identify genes that are relevant for thermotolerance or heat stress memory. Knowing how this cell death pathway is regulated at the molecular and cellular level in plants might offer new tools of practical value in agricultural applications. With global temperatures predicted to rise, research aimed at reducing plant susceptibility to heat stress is likely to have a significant impact on future crop yields.

Supported by ANPCyT, CONICET and ICGEB.

P1.17 BREEDING MICRONUTRIENT DENSE BEAN VARIETIES IN EASTERN AFRICA

Wednesday 5 July 2023 15:00

Paul M Kimani (UNVERSITY OF NAIROBI, Kenya)

pmkimani@uonbi.ac.ke

Development and utilization of drought tolerant, biofortified varieties is probably the most effective, sustainable and potentially longlasting strategy for reducing micronutrient deficiencies and coping with frequent droughts in bean production areas in Africa. A regional breeding program based at the University of Nairobi was initiated in 2004 to develop and disseminate micronutrient-dense bean varieties. This program has gone through four phases: i) Collection and characterisation of regional germplasm; ii) selection, evaluation and dissemination of first generation micronutrient-dense lines; iii) development of second generation breeding populations combining drought tolerance, higher Fe and Zn concentration, and resistance to diseases, and iv) determination of agronomic potential of second generation lines. Results showed that considerable genetic variation existed among the 2849 lines collected from 9 countries to facilitate improvement of iron by more than 80% and zinc by more than 50%. Thirty-eight fast track lines (Fe>70ppm, Zn>30ppm) were validated in participatory variety trials and selections released in 9 countries. Forty-seven F2 populations segregating for mineral density, resistance to biotic and abiotic stresses, grain type and yield potential were developed and advanced to F8 . Iron concentration of these lines varied from 30 to 130 ppm, and zinc from 10 to 60 ppm. Outstanding lines were selected from BF01, BF03, BF07, BF16 and BF 36 populations. Eight-four lines had 50% more yield than their parents in moisture stressed conditions, suggesting transgressive segregation. Results indicated that varieties combining high micronutrient density, resistance to diseases and drought, and marketable grain types can be developed from these populations.

Key words: Iron, zinc, biofortification, variation

P1.18 UNDERSTANDING MINERAL BIOAVAILABILITY FOR BREEDING IRON AND ZINC-RICH BEANS

Wednesday 5 July 2023 15:30

Raul Huertas (The James Hutton Institute, United Kingdom), Barbara Karpinska (University of Birmingham, United Kingdom), Christine H Foyer (University of Birmingham, United Kingdom), Derek Stewart (The James Hutton Institute, United Kingdom), Robert Hancock (The James Hutton Institute, United Kingdom)

raul.huertas@hutton.ac.uk

Iron (Fe) and zinc (Zn) deficiencies are a major threat to nutritional security and public health, especially for low-income regions. Common bean (Phaseolus vulgaris L.) is the most consumed food grain legume worldwide and the primary source of protein and micronutrients for >200 million people in Africa. The Fe and Zn content in seeds is insufficient to meet the nutritional requirements in many cultivars, so there is a need to develop and identify cultivars able to accumulate bioavailable forms of these minerals.

A key issue in the development of high mineral cultivars is the relationship between total and bioavailable mineral content. To address this issue, several bean genotypes with similar genetic backgrounds but high natural variability in their raw grain Fe and Zn content were evaluated. An optimized in vitro protocol, simulating human digestion combined with the quantification of antinutritional compounds (phytate and polyphenols) allowed us to determine factors that influence Fe and Zn bioavailability. Results indicated that enhanced dry seed content of Fe and Zn does not necessarily result in higher bioavailable minerals in cooked beans. Moreover, there was little influence of antinutritional factors, although cooking methods did.

Current work has taken a combined approach of dynamic ionomics and transcriptomic analysis during the development of grains and pods in genotypes with contrasting mineral accumulation. We aimed to determine key biological processes and genes of mineral deposition in grains. Our results will contribute to the identification of potential targets for marker-assisted selection and genetic/biotechnological approaches focused on improved human nutrition.

P1.19 OSTH1, A NEW POTENTIAL TARGET FOR THIAMINBIOFORTIFICATION IN RICE

Wednesday 5 July 2023 15:45

Maria Faustino (Instituto de Tecnologia Química e Biológica

António Xavier Universidade Nova de Lisboa, Portugal), Tiago Lourenço (Instituto de Tecnologia Química e Biológica

António Xavier Universidade Nova de Lisboa, Portugal), Simon Strobbe (Laboratory of Functional Plant Biology

Department of Biology Ghent University, Belgium), Da Cao (Laboratory of Functional Plant Biology Department of Biology Ghent University, Belgium), André Fonseca (Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa, Portugal), Isabel Rocha (Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa, Portugal), Dominique Van Der Straeten (Laboratory of Functional Plant Biology Department of Biology Ghent University, Belgium), M. Margarida Oliveira (Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa, Portugal)

mvfaustino.9@gmail.com

Nutrition quality is not secured for the whole population. In fact, over 2 billion people still suffer from hidden hunger. Rice is the world’s second staple crop and the primary source of calories in developing countries. However, white rice, the most consumed form, has an insufficient concentration of several vitamins such as thiamin (B1). Thus, thiamin deficiency is widespread in developing countries, causing several health-related conditions. Biofortification via metabolic engineering is considered a powerful strategy to mitigate hidden hunger. Nonetheless, to redesign its pathway a deep knowledge is required. Aiming to identify the best biofortification strategy, we created a kinetic model of the thiamin pathway. The model confirmed that THIC, THI1, and TH1 are key enzymes for thiamin biofortification. We focused our efforts onOsTH1to extend our knowledge on this crucial gene for thiamin biofortification. We characterizedOsTH1by analyzing its sequence and gene expression data and performing a phylogenetic analysis. Using yeast knock-out mutants impaired in thiamin production, we functionally complemented the phenotype through heterologous expression ofLOC_Os12g09000/OsTH1. Furthermore, we report the accumulation of thiamin in rice callus by the sole

overexpression ofOsTH1, reaching a 50% increase in thiamin content. Here, we highlight the pivotal role ofOsTH1in metabolic engineering strategies by (1) highlighting it as one of the key enzymes for thiamin biofortification, (2) verifying its crucial role in ricede novothiamin biosynthesis, and (3) achieving thiamin accumulation in rice callus by its sole expression.

P1.20 CONSERVED SIGNALLING COMPONENTS PROMOTE BARLEY GRAINHULL ADHESION

Wednesday 5 July 2023 16:00

Linsan Liu (University of Dundee, United Kingdom), Chiara Campoli (The James Hutton Institute, United Kingdom), Trisha McAllister (University of Dundee, United Kingdom), Micha Bayer (The James Hutton Institute, United Kingdom), Luke Ramsay (The James Hutton Institute, United Kingdom), Robbie Waugh (The James Hutton Institute, United Kingdom), Sarah McKim (University of Dundee, United Kingdom)

ltliu@dundee.ac.uk

In many cereal species, grains develop within a protective hull. Barley is distinctive in producing ‘covered’ grain where the hulls tightly adhere to a sticky cementing layer secreted by the grain surface (pericarp). Deletion of theNUDUM(NUD) gene, encoding a transcription factor, removes the sticky layer, leading to non-adherent ‘naked’ grain. However, barley grain can also show an intermediate phenotype called ‘skinning’ where compromised adhesion causes partial hull shed, an undesirable trait for the malting industry and observed more frequently in new cultivars. We used stable skinning mutants as well as anuddeletion mutant, introgressed into a normally tightly adherent cultivar, Bowman, as tools to understand the genetic and developmental mechanisms of grain-hull adhesion. We found that defective function of genes encoding conserved signalling regulators, a MAP kinase kinase kinase and a scaffolding protein, underlies two of these mutants. Developing grain in mutants exhibit uneven pericarp cuticle thickness and composition, distorted pericarp structure, and patches of nonsticky pericarp as well as clusters of epidermal hairs on the inner side of the hull. These genes are expressed early in grain development and comparative transcriptomic analysis suggests that mutants show altered gene expression aligned with these phenotypes. Interestingly, we previously showed that these regulators also coordinate epidermal patterning and cuticle formation in leaves. Taken together, I conclude that these signalling regulators, crucial for vegetative epidermal features, also play important roles in pericarp and hulls which may promote cementing layer secretion and smooth contact interfaces to promote strong grain-hull adhesion.

POSTER SESSION

Wednesday 5 July 2023 17:15-19:15

P1.21 NITROGEN MOBILIZATION AND USAGE WITHIN BRASSICA CROPS

Wednesday 5 July 2023

POSTER SESSION

Madhury Paul (University of Warwick, United Kingdom), Graham Teakle (University of Warwick, United Kingdom), Guy Barker (University of Warwick, United Kingdom)

Madhury.Paul@warwick.ac.uk

Mineral fertilization has improved crop yield over the last century but also contributes to air and water pollution. Nitrogen (N) fertiliser is a major anthropogenic source of nitrogenous greenhouse gas emissions. In addition, 40% of waterbody pollution is the result of agricultural pollution in rural areas. Therefore, reducing nitrogen input while maintaining a high crop yield is essential for sustainable agriculture

Oilseed rape (Brassica napus L.) is the world’s third largest source of vegetable oil, behind soybean and palm, and the UK’s largest source of vegetable oil. Rapeseed production requires high N input compared to other crops. However, large differences in N concentration have previously been found in different accessions of B. napus.

My aim is to understand genetic variation underlying the uptake, storage and mobilisation of N in a small set of B. napus cultivars and to map genes associated with Nitrogen use efficiency (NUE) related traits in order to improve NUE in B. napus.

In the present investigation, a field trial of seven contrasting oilseed rape varieties is being grown at the Wellesbourne campus to study the genotypic and phenotypic variation under high and low N fertiliser treatments. In addition, a mapping population is being developed by crossing between two winter oilseed rape varieties. A candidate gene approach will also be used to study the behaviour of known genes associated with N uptake and metabolism. This work will improve our ability to enhance yields of oilseed rape while lowering the fertilizer requirements and at the same time reducing the environmental footprint.

P2 - SUGAR METABOLISM, TRANSPORT AND SIGNALLING IN PLANTS

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

P2.2 MINING THE PLANT'S TOR/SNRK1 NITROGEN SIGNALLING NETWORK VIA COMBINATORIAL CRISPR-BASED GENE EDITING

Wednesday 5 July 2023 POSTER SESSION

Freya Persyn (VIB-UGhent Center for Plant Systems Biology, Belgium), Wouter Smagghe (VIB-UGhent Center for Plant Systems Biology, Belgium), Toon Mertens (VIB-UGhent Center for Plant Systems Biology, Belgium), Thomas Smorscek (VIB-UGhent Center for Plant Systems Biology, Belgium), Dominique Eeckhout (VIB-UGhent Center for Plant Systems Biology, Belgium), Nancy De Winne (VIB-UGhent Center for Plant Systems Biology, Belgium), Geert Persiau (VIB-UGhent Center for Plant Systems Biology, Belgium), Eveline Van De Slijke (VIB-UGhent Center for Plant Systems Biology, Belgium), Astrid Gadeyne (VIB-UGhent Center for Plant Systems Biology, Belgium), Jelle Van Leene (VIB-UGhent Center for Plant Systems Biology, Belgium), Geert De Jaeger (VIB-UGhent Center for Plant Systems Biology, Belgium)

frper@psb.vib-ugent.be

Plants have developed a specific nutrient signalling network which is used to sense their energy and nutrient levels in order to balance their growth with the ever-changing environmental conditions. TOR (Target Of Rapamycin) and SnRK1 (Snf-Related Kinase 1) are two conserved kinase complexes that form an important, central signalling hub at the heart of this network.

We have mapped the N-dependent interactome around these complexes using AP-MS and proximity labelling approaches, and compared it to our carbon signalling networks to identify both upstream and downstream signalling nodes involved in regulating nitrogen use efficiency.

In addition to protein-protein interactions, nutrient signalling heavily relies upon phosphorylation, which is mapped via phosphoproteomics. Starting from this dataset, we use a pooled, combinatorial CRISPR approach in Arabidopsis thaliana as a tool to screen for genotypes that

enhance plant growth under nitrogen stress conditions. Besides gene knock-out and overexpression, base and prime editing will be used to edit regulatory phosphosites.

Our mutant plant libraries will be screened towards beneficial mutations by growth on low nitrogen. Growth-promoting genotypic combinations will be identified via NGS and their function will be analyzed.

P2.3 THE MISSING LINK: HOW CLASS II TPS PROTEINS REGULATE THE SNRK1 KINASE

Wednesday 5 July 2023 POSTER SESSION

Thomas Smorscek (VIB-UGent Center for Plant Systems Biology, Belgium), Freya Persyn (VIB-UGent Center for Plant Systems Biology, Belgium), Wouter Smagghe (VIB-UGent Center for Plant Systems Biology, Belgium), Toon Mertens (VIB-UGent Center for Plant Systems Biology, Belgium), Dominique Eeckhout (VIB-UGent Center for Plant Systems Biology, Belgium), Nancy De Winne (VIB-UGent Center for Plant Systems Biology, Belgium), Geert Persiau (VIB-UGent Center for Plant Systems Biology, Belgium), Eveline Van De Slijke (VIB-UGent Center for Plant Systems Biology, Belgium), Roman Pleskot (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic), Filip Rolland (KU Leuven Plant Institute—LPI HeverleeLeuven, Belgium), Jelle Van Leene (VIB-UGent Center for Plant Systems Biology, Belgium), Geert De Jaeger (VIB-UGent Center for Plant Systems Biology, Belgium)

thomas.smorscek@ugent.be

Plants require minute sensing of internal and external cues to dynamically adapt to changing environmental conditions. SnRK1 is a kinase complex at the centre of this process and is activated by lowenergy stress conditions to ensure energetic homeostasis. By mapping the protein interaction landscape of SnRK1 through affinity purification and proximity labelling mass spectrometry, we identified class II TPS proteins as stable interactors of the kinase complex and further investigation has shown them to be inhibitors of SnRK1 signalling. Arabidopsis encodes seven of these class II TPS proteins and all seven harbour conserved residues that may constitute a T6P binding site, yet they show no metabolic activity towards T6P.

As T6P is a signal metabolite functioning as a proxy for sucrose and as it is a known inhibitor of SnRK1 activity, we hypothesize that T6P exerts its effects on SnRK1 – at least in part – through binding

ORGANISED BY: JOHN LUNN (MAX PLANCK INSTITUTE OF MOLECULAR PLANT PHYSIOLOGY) , FRANZISKA FICHTNER (HEINRICH HEINE UNIVERSITY)

to class II TPS proteins. To address this question, we performed T6Pdependent cross-linking MS and dedicated biochemical and cellular assays, indicating that T6P binds class II TPS proteins and that T6Pbinding potentiates class II TPS-dependent inhibition of SnRK1α1 activity. To further study class II TPS gene functionin plantaand to contend with plausible redundancy of these genes, we generated a set of high-order class II TPS knockout mutants that accumulate less anthocyanin, suggesting increased SnRK1 signalling. Next, we aim to further consolidate the T6P-dependency of class II TPS proteins and corroborate these findings using anin vivoSnRK1 activity reporter.

PLANTS:

Thursday 6 July 2023 09:00

Mark Stitt (Max Planck Institute of Molecular Plant Physiology, Germany)

mstitt@mpimp-golm.mpg.de

overview the early days of plant sugar sensing research in the last decade of the last century, including in particular insights gained from the early use of transgenic plants, where unexpected phenotypes revealed that metabolic signals impact broadly on metabolism and growth. I will next discuss the importance of sugar-signalling in allowing plants to cope with a changing environment, including their responses to light regimes and elevated atmospheric CO2. I will use diel starch turnover as an example of the amazing precision with which plants coordinate resource availability, storage and growth in a fluctuating environment. I will then discuss, as a specific example, how trehalose 6-phosphate acts as a signal for sucrose availability with broad impacts at the transcriptional and post-translational level on metabolism and growth. I will also discuss our current mechanistic understanding of trehalose 6-phosphate signalling, including its role as a plant-specific regulator of SnRK1, and recent insights into how trehalose 6-phosphate may interact with other signalling pathways in plants. The broad impact and rapid secondary changes that themselves trigger further signalling pathways make analysis of trehalose 6-phoohate signalling very challenging and emphasize the need for more powerful and specific analytic and genetic tools to dissect the highly integrated sugar-signalling network.

P2.5

Thursday 6 July 2023 09:45

in vascular plants, but shares this role with polyols (e.g. sorbitol) and raffinose-family oligosaccharides (RFOs) in some species. There is also diversity between species in the mechanisms of phloem loading (passive symplastic, polymer-trapping and apoplastic) and the types of carbohydrate accumulated in leaves as transitory storage reserves. Trehalose 6-phosphate (Tre6P) is an essential signal metabolite that regulates sucrose homeostasis and signals the availability of sucrose, thereby linking plant growth and development to the metabolic status of the plant. Our understanding of the relationship between sucrose and Tre6P is based primarily on studies inArabidopsis thaliana, an apoplastic phloem loading species that stores mainly starch in its leaves. To compare the function of Tre6P across species, we performed metabolite profiling of leaf samples collected throughout a 24-h diel cycle from a range of species with different carbohydrate storage and transport strategies:Arabidopsis thaliana, strawberry (Fragaria x ananassa),Alchemilla mollis, melon (Cucumis melo), bread wheat (Triticum aestivum), andPlantago major. The levels of Tre6P differed over 100-fold between species, but a positive correlation between sucrose and Tre6P was observed in all species. We used network analysis to explore other metabolite connections in central metabolism, revealing conserved and divergent features within the metabolic networks of these species.

P2.6 CHANGES IN SUCROSE DYNAMICS AND ITS EFFECTS ON REPRODUCTIVE DEVELOPMENT IN ARABIDOPSIS

Thursday 6 July 2023 10:00

Yohanna Miotto (Max Planck Institute for Plant Breeding Research, Germany), Adrian Roggen (Max Planck Institute for Plant Breeding Research, Germany), Franziska Fichtner (Heinrich Heine University, Germany), George Coupland (Max Planck Institute for Plant Breeding Research, Germany) ymiotto@mpipz.mpg.de

Lunn@mpimp-golm.mpg.de

There is enormous diversity in plant metabolism, including the central pathways of carbohydrate metabolism. Sucrose is a major product of photosynthesis in plants and the most common transport sugar

The plant life-cycle can be divided into distinct phases and the transitions between these are tightly controlled by developmental and environmental cues. Extensive genetic evidence indicates that the floral transition is controlled by a complex gene regulatory network (GRN) that responds to external inputs such as light and temperature and internal factors including plant age, carbohydrate status and hormones. In Arabidopsis, one specific module of this GRN involves the interplay between microRNA156 (miR156) and SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) genes. Under short-days, the level of miR156, which represses the expression ofSPLgenes, declines with the increasing developmental age of the plant. As a result, in older plants, the levels of SPL15 and SPL4 proteins accumulate and this leads to the activation of down-stream factors that initiate the transition to the reproductive development. It has been suggested that the age-related decline in miR156 levels is at least in part regulated by the sugar content in the plant. Cytosolic invertases (CINVs) are responsible for converting sucrose into hexoses, therefore are considered a key step of cellular carbon metabolism. In cinv1cinv2 plants the shoot apical meristem (SAM) undergoes floral transition later than wild-type, supporting the late-flowering phenotype observed in long- and short-day conditions. We are using a combination of phenotypic, genetic and confocal microscopy in order to address how these enzymes contribute to floral transition, for example whether they act through the miR156/SPL module, and the possible morphological consequences of disrupting carbon metabolism in terms of cellular behavior at the SAM.

P2.4 SUGAR SENSING IN

WHERE IT ALL STARTED, HOW IT HAS DEVELOPED AND DEVELOPMENTS IN TREHALOSE 6-PHOSPHATE SIGNALING

SUGAR METABOLISM AND SIGNALLING IN DIVERSE SPECIES WITH DIFFERENT CARBOHYDRATE STORAGE AND TRANSPORT STRATEGIES

John E. Lunn (Max Planck Institute of Molecular Plant Physiology, Germany)

P2.7 SINGLE-CELL ANALYSIS REVEALS COMPARTMENTALISATION OF THE TREHALOSE-6-PHOSPHATE PATHWAY IN MAIZE LEAVES

Thursday 6 July 2023 10:15

Gabriela Madrid (University of Florida, United States), Susan K. Boehlein (University of Florida, United States), Kelly M. Balmant (University of Florida, United States), Kristen A. Leach (University of Florida, United States), Matias Kirst (University of Florida, United States), Marcio F. R. Resende Jr (University of Florida, United States)

gabriela.madridc@ufl.ed

Trehalose-6-phosphate (Tre6P) is a key signalling metabolite that plays a crucial role in the regulation of plant growth and development, as well as in the response to abiotic stress. Tre6P acts as a sucrose availability signal by monitoring the metabolic status of the plant. In maize, it is involved in regulating starch synthesis, carbon metabolism, and sucrose transport. The Tre6P synthesis pathway is composed of two enzymes, trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP), both of which are encoded by large multi-gene families with specific spatiotemporal expression patterns. We aimed to investigate the expression patterns of the Tre6P pathway at the cell type level in maize leaf tissue. For this, we used a single-nuclei RNA sequencing approach. Our results revealed that the pathway exhibits inter-cellular compartmentalisation, with ZmTPS1, which synthesises Tre6P, specifically expressed in the companion cells/sieve elements complex, which is consistent with previous findings in Arabidopsis thaliana and with a possible role in sucrose allocation. ZmTPP2 and ZmTPP6 were found to be expressed in bundle sheath cells, while ZmTPP14 was highly expressed in mesophyll cells. Both cell types are essential for sucrose and starch synthesis in maize. In addition, we built cell type-specific gene regulatory networks and identified key transcriptional regulators for the pathway, including SnRK1, which plays a role in sucrose signalling and energy homeostasis. Our study provides the first evidence of cellular compartmentalisation of the Tre6P pathway and points to its possible role in carbon allocation between sink and source tissues in a C4 crop.

P2.8 SUGAR TRANSPORT IN STOMATAL MOVEMENTS

Thursday 6 July 2023 11:00

The double mutantssweet1sweet5,sweet1sweet4, andsweet4sweet5 display guard cell-specific impairments in starch and sugar metabolism, which impact on stomatal movements.

P2.9 BRANCHED OLIGOSACCHARIDES CAUSE SPONTANEOUS GRANULE INITIATION IN ARABIDOPSIS THALIANA CHLOROPLASTS

Thursday 6 July 2023 11:30

Arvid JM Heutinck (ETH Zürich, Switzerland), Selina Camenisch (Institute of Molecular Plant Biology ETH Zürich, Switzerland), Michaela Fischer-Stettler (Institute of Molecular Plant Biology ETH Zürich, Switzerland), Samuel C Zeeman (Institute of Molecular Plant Biology ETH Zürich, Switzerland)

arvid.heutinck@biol.ethz.ch

Plants store starch in chloroplasts to use as source of energy during the night. Starch granule formation relies on the elaboration of maltooligosaccharide primers. PROTEIN TARGETING TO STARCH 2 (PTST2) and STARCH SYNTHASE 4 (SS4) are essential to select and elongate oligosaccharide primers, respectively, and very few granules are initiated in their absence. Recently, much has been discovered on these and other proteins involved in this process. However, the precise origin and metabolism of the priming glucans remain unknown. Soluble oligosaccharides in chloroplasts can originate from starch breakdown, and their amount and composition is altered when degradation is impeded. The Arabidopsis double mutant deficient in the debranching enzymes ISOAMYLASE 3 (ISA3) and LIMIT DEXTRINASE (LDA) uniquely accumulates branched malto-oligosaccharides at night. These are cleaved off of the starch granule surface by the endoamylase α-AMYLASE 3 (AMY3), but cannot be fully metabolised. Interestingly, the isa3 lda double mutant also shows a massive increase in granule number per chloroplast. By contrast, the triple mutant amy3 isa3 lda lacks branched oligosaccharides and has normal granule numbers. This indicates that the branched oligosaccharides cause granule overinitiation.

Plants that lack both debranching enzymes and either PTST2 or SS4 still show granule over-initiation, indicating that this process can occur independently of the canonical granule initiation pathway. These findings give new insight into how starch granules are initiated and established, and show how these processes can be used to influence their size, number, and morphological characteristics – traits known to affect starch properties.

diana.santelia@usys.ethz.ch

Stomata are leaf pores bordered by a pair of guard cells that open and close to facilitate CO2 uptake for photosynthesis and evapotranspirational water loss. Despite guard cells have some features of autotrophic tissues, the transport of mesophyll-derived sugars across guard cell cellular membranes plays an essential role in connecting stomatal movements with photosynthesis for efficient plant growth. Besides the previously characterized Sugar Transport Protein 1 and 4 (STP1 and 4), we have identified plasma membrane Sugar Will Eventually be Exported Transporter 1, 4 and 5 (SWEET1, 4, 5) as novel players for guard cell starch metabolism and stomatal movements inArabidopsis thaliana.

P2.10 MAKING A FRESH STARCH: BIOCHEMICAL REGULATION OF STARCH GRANULE INITIATION IN ARABIDOPSIS AND WHEAT

Thursday 6 July 2023 11:45

Diana Santelia (ETH Zürich, Switzerland)

Jiawen Chen (John Innes Centre, United Kingdom),

Erica Hawkins (John Innes Centre, United Kingdom),

Brendan Fahy (John Innes Centre, United Kingdom),

J. Elaine Barclay (John Innes Centre, United Kingdom),

Stanislav Kurass (John Innes Centre, United Kingdom),

Carlo Martins (John Innes Centre, United Kingdom),

Gerhard Saalbach (John Innes Centre, United Kingdom),

Jake Richardson (John Innes Centre, United Kingdom),

David Lawson (John Innes Centre, United Kingdom),

Michael Webster (John Innes Centre, United Kingdom), David Seung (John Innes Centre, United Kingdom)

jiawen.chen@jic.ac.uk

Starch is the main storage carbohydrate in plants, important for maintaining growth and metabolism. Much is still unknown about the first steps in starch granule initiation, which determine the number, size and shape of granules that form within a plastid. Several granule initiation proteins have been discovered in Arabidopsis, with Starch Synthase 4 (AtSS4) at the centre, as the only enzyme. One of the direct biochemical interactors of AtSS4 is Myosin Resembling Chloroplast protein (AtMRC). We explored the biochemistry and function of these proteins in Arabidopsis and wheat, where granule initiation can be examined in both leaf chloroplasts and grain amyloplasts. The wheat endosperm has a unique spatio-temporal pattern of granule initiation, leading to large A-granules and small B-granules. We found that TaSS4 plays an essential role in ensuring correct granule shape in the endosperm, while TaMRC regulates the correct timing and amount of B-granule formation. However, in wheat leaves, TaSS4 and TaMRC both seem to promote granule initiation, suggesting tissue-specific protein functions. TaSS4 and TaMRC can also interact, but the in planta context of these interactions is unknown. In size exclusion chromatography, AtSS4 and TaSS4 exist at high molecular weight, both in leaves and in vitro. Interestingly, negative stain TEM of the recombinant AtSS4 reveals densities that are consistent with an AtSS4 dimer, suggesting that stable AtSS4 dimers could assemble into more transient homooligomeric complexes, or the AtSS4 dimer might have an extended shape. This work provides potential for further biochemical and structural characterisation of SS4.

P2.11 DISTINCT BIOCHEMICAL MECHANISMS ARE INVOLVED IN THE INITIATION OF A- AND B-TYPE STARCH GRANULES DURING WHEAT GRAIN DEVELOPMENT

Thursday 6 July 2023 12:00

Nitin Uttam Kamble (John Innes Centre, United Kingdom), Farrukh Makhamadjonov (John Innes Centre, United Kingdom), Brendan Fahy (John Innes Centre, United Kingdom), David Seung (John Innes Centre, United Kingdom)

Nitin.Kamble@jic.ac.uk

Starch in the wheat endosperm is vitally important as a staple carbohydrate in our diet. It is synthesised as semi-crystalline granules composed of glucose polymers. Wheat endosperms contain large A-type granules that initiate at early grain development, and small B-type granules that initiate in later grain development. We demonstrate that the plastidial α-glucan phosphorylase (PHS1), a conserved enzyme that can elongate starch polymers, plays a specialised role in initiating the B-type granules. Mutants of durum wheat deficient in PHS1 had

normal A-type granules, but fewer and larger B-type granules. Starch content, grain size and grain yield per plant were not affected by the mutations. PHS1 interacts with BGC1 – a carbohydrate-binding protein essential for normal B-type granule initiation. Overall, we propose that the initiation of A- and B-type granules in wheat occur via distinct biochemical mechanisms. The implications of these discoveries to improving grain quality will be discussed.

P2.12 A TPR MIDDLEMAN TO MEDIATE SNRK1 DEPENDENT CHLOROPLASTIC STARCH DEGRADATION

Thursday 6 July 2023 12:15

Toon Mertens (VIB-UGhent Center for Plant Systems Biology, Belgium), Wouter Smagghe (VIB-UGhent Center for Plant Systems Biology, Belgium), Freya Persyn (VIB-UGhent Center for Plant Systems Biology, Belgium), Thomas Smorscek (VIB-UGhent Center for Plant Systems Biology, Belgium), Dominique Eeckhout (VIB-UGhent Center for Plant Systems Biology, Belgium), Nancy De Winne (VIB-UGhent Center for Plant Systems Biology, Belgium), Geert Persiau (VIB-UGhent Center for Plant Systems Biology, Belgium), Eveline Van De Slijke (VIB-UGhent Center for Plant Systems Biology, Belgium), Geert De Jaeger (VIB-UGhent Center for Plant Systems Biology, Belgium), Jelle Van Leene (VIB-UGhent Center for Plant Systems Biology, Belgium) toon.mertens@psb.vib-ugent.be

Plants build up carbon reserves during the day in the form of starch in photosynthesizing tissues. This transitory starch serves as a C supply at night when CO2 cannot be fixed by photosynthesis. The signaling molecule Trehalose-6-phosphate (T6P) and the plant homeostatic master regulator SnRK1 are proposed determining factors in this dynamic interplay between starch synthesis and breakdown. SnRK1 mutant plants are affected in starch metabolism but pleiotropic effects of altered SnRK1 activity and fundamental differences between source and sink sugar metabolism complicate interpretation. SnRK1 signalling is suggested to account, at least in part, for the effect of T6P on starch metabolism. However, how this regulation of starch metabolism occurs remains largely elusive.

Using AP-MS with multiple SnRK1 subunits as bait in Arabidopsis thaliana cell culture, we recently identified the unknown Tetratricopeptide repeat protein TPR149 as a novel prevalent SnRK1 interactor. Reciprocal AP-MS with TPR149 as bait confirmed the SnRK1 interaction and revealed a strong connection with chloroplastic ß-amylase complexes, in agreement with its high co-expression with starch metabolism genes. The interactions with ß-amylases were confirmed by TurboID-based proximity labeling in the chloroplasts. Consistent with the observed interactions, TPR149 localizes to starch granules on the chloroplast in Nicotiana benthamiana, but is absent from the chloroplast when co-expressed with SnRK1 subunits. Preliminary lugol staining experiments of Arabidopsis TPR149 knockout plants indicate that TPR149 functions as a negative regulator of starch degradation. Based on these observations, we hypothesize that SnRK1 phosphorylates and retains TPR149 from the chloroplast to stimulate starch degradation.

P2.13 REGULATION OF THE PLANT ENERGY SENSOR SNRK1 BY SUBCELLULAR LOCALISATION.

Thursday 6 July 2023 14:30

Filip A Rolland (KU Leuven, Belgium)

filip.rolland@kuleuven.be

SnRK1 (Sucrose non-fermenting1-Related Kinase1) acts as a cellular fuel gauge, monitoring and maintaining plants’ energy balance. In addition to responding to carbon and energy depletion caused by biotic and abiotic stress conditions (directly or indirectly affecting metabolism), SnRK1 also gatekeeps important developmental transitions associated with changes in metabolic demand and supplies. It directly targets key metabolic enzymes, but also triggers transcriptional reprogramming and, together with SnRK2 and SnRK3 kinases, functions in an intricate nutrient and stress responsive network with the (antagonistic) TOR (Target of Rapamycin) kinase. SnRK1 belongs to a conserved eukaryotic family of proteins, including fungal SNF1 (Sucrose Nonfermenting1) and animal AMPK (AMP-activated kinase). These function as hetero-trimeric complexes, with a catalytic α subunit and regulatory (scaffolding) β and (nucleotide-binding) γ subunits. But while SNF1/ AMPK/SnRK1 function and overall complex configuration appear highly conserved, the plant kinases have also diverged, with plantspecific structural features and regulatory mechanisms likely linked to their unique lifestyle. An apparent default activity (with significant autophosphorylation) and loss of control by nucleotide charge are consistent with negative regulation of SnRK1 by sugar-phosphates in conditions of carbon and energy affluence (and thus de-repression rather than activation). SnRK1 also is a nucleo-cytoplasmic protein and its controlled distribution is important for both stress responses and optimal growth and development. Remarkably, SnRK1 activation by the GRIK kinases occurs at the tonoplast, while the inactivating phosphatases are mainly localized in the nucleus. This suggests a continuous nucleo-cytoplasmic shuttling. Ongoing research is exploring the molecular mechanisms of SnRK1 subcellular dynamics.

P2.14 EXPLORING RAFFINOSE AS A NOVEL PLANT AUTOPHAGY INDUCER

Thursday 6 July 2023 15:00

Tamar Avin-Wittenberg (The Hebrew University of Jerusalem, Israel), Sahar Magen (The Hebrew University of Jerusalem, Israel), Sahar Daniel (The Hebrew University of Jerusalem, Israel)

tamar.avin-wittenberg@mail.huji.ac.il

Food security is one of humanity’s greatest challenges, especially in light of climate change and diminishing arable land. Developing new agricultural solutions requires an increased understanding of the mechanisms regulating plant growth and stress resistance. Autophagy, an intracellular degradation and recycling process, is gaining attention as a stress-coping mechanism in eukaryotes. Despite its potential importance in cellular homeostasis and stress response, it remains under-researched in plants compared to yeast and animal systems. Autophagy is induced by many nutrient-deprivation conditions and biotic and abiotic stresses in plants. Moreover, autophagy-deficient mutants display early senescence, reduced yield, and hypersensitivity to starvation and abiotic stress. This suggests that autophagy

enhancement might increase plant performance. Indeed, the overexpression of autophagy-related genes in several plant species increased plant size, yield, and stress resistance. Regulatory restrictions on transgenic plants hinder direct intervention in autophagy in crops. Thus, other means of modulating autophagy are needed.

An alternative approach is the chemical induction of autophagy. Yet, not many autophagy activators are known in plants. Previous works from plant and animal systems demonstrated the possible role of regulatory sugars in autophagy stimulation. We identified the trisaccharide raffinose as an autophagy inducer in plants. Raffinose accumulates in plants during abiotic stress and improves stress tolerance, strengthening our hypothesis that it naturally functions as an autophagy regulator. Raffinose treatment activates autophagy and positively impacts plant growth and yield in an autophagydependent manner. We also demonstrate that raffinose treatment increased the performance of several model and crop species, both monocot and eudicot.

P2.15 MAPPING OF THE PLANT SNRK1 KINASE SIGNALING NETWORK TO OPTIMIZE GROWTH UNDER NUTRIENTLIMITING CONDITIONS

Thursday 6 July 2023 15:15

Jelle Van Leene (VIBUGhent, Belgium), Dominique Eeckhout (VIBUGhent, Belgium), Nancy De Winne (VIBUGhent, Belgium), Geert Persiau (VIBUGhent, Belgium), Eveline Van De Slijke (VIBUGhent, Belgium), Toon Mertens (VIBUGhent, Belgium), Freya Perseyn (VIBUGhent, Belgium), Wouter Smagghe (VIBUGhent, Belgium), Thomas Smorscek (VIBUGhent, Belgium), Roman Pleskot (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic), Filip Rolland (KU Leuven Plant Institute, Belgium), Geert De Jaeger (VIBUGhent, Belgium)

jelle.vanleene@psb.vib-ugent.be

The central metabolic regulator SnRK1 controls plant growth and survival upon activation by energy depletion, while also gatekeeping developmental transitions and nutrient allocation between source and sink tissues. Despite significant progress made in recent years, many questions still remain on how SnRK1 senses cellular energy and nutrient levels in plants, and how it translates this information to ensure optimal growth and survival. Therefore, we are mapping proteome-wide SnRK1 signaling networks in Arabidopsis in relation to nutrient availability. Through phosphoproteomics we discovered a diverse set of novel SnRK1 substrates, providing a comprehensive view on the processes targeted by SnRK1 upon carbon starvation. Besides, we combined affinity purification, proximity labeling and cross linking mass spectrometry to shed light on the interaction landscape, structure and post-translational modification state of the core heterotrimeric SnRK1 kinase complex. At the intersection of this multi-dimensional dataset, we discovered a strong association of SnRK1 with class II T6P synthase-like proteins. Biochemical and cellular assays showed that these proteins function as negative regulators of SnRK1, and currently we are investigating if they function as carbon sensors that integrate T6P levels with SnRK1 activity. In parallel, we are studying the relation of SnRK1 with other network components focusing mainly on proteins of unknown function, establishing for instance novel links with starch metabolism or SnRK1-mediated transcriptional reprogramming. Finally, we are developing tools to monitor SnRK1 kinase activityin vivo, which we will apply to directly link the effect of CRISPR-based SnRK1 network perturbation on the plant phenotype with SnRK1 activity.

P2.16 CAUGHT IN THE ACT: PHASE SEPARATION-BASED REAL-TIME VISUALIZATION OF SNRK1 KINASE ACTIVITY DURING PLANT GROWTH AND DEVELOPMENT

Thursday 6 July 2023 15:30

Wouter Smagghe (VIB-UGent Center for Plant Systems Biology, Belgium), Alaeddine Safi (VIB-UGent Center for Plant Systems Biology, Belgium), Toon Mertens (VIB-UGent Center for Plant Systems Biology, Belgium), Freya Persyn (VIB-UGent Center for Plant Systems Biology, Belgium), Thomas Smorscek (VIB-UGent Center for Plant Systems Biology, Belgium), Nancy De Winne (VIB-UGent Center for Plant Systems Biology, Belgium), Eveline Van De Slijke (VIB-UGent Center for Plant Systems Biology, Belgium), Geert Persiau (VIB-UGent Center for Plant Systems Biology, Belgium), Tom Beeckman (VIB-UGent Center for Plant Systems Biology, Belgium), Steffen Vanneste (Department of Plant and Crops Ghent University, Belgium), Geert De Jaeger (VIB-UGent Center for Plant Systems Biology, Belgium), Jelle Van Leene (VIB-UGent Center for Plant Systems Biology, Belgium)

wouter.smagghe@psb.vib-ugent.be

In an ever-changing environment, plants have to adapt their growth according to internal and external conditions, like nutrient and energy levels. Hereto, plants have developed a vast and complex signaling network, meticulously integrating all these cues into permissive or restrictive growth decisions. Within this network, Sucrose nonfermenting kinase 1 (SnRK1) acts as a molecular fuel gauge. Hereto, it restrains growth under restrictive conditions and favors catabolism to release energy and nutrients, ensuring survival. Albeit this ubiquitous role, the detailed spatiotemporal dynamics on how SnRK1 regulates plant growth still remains elusive given the dynamic post-translational regulation executed by kinases, and the lack of adequate tools that can capture dynamics in phosphorylation status, and thus kinase activity, at cellular resolution.

Here, we generated and exploited the SYnthetic Multivalency in PLants (SYMPL)-vector set to assay kinase activity (SPARK - Separation of Phases-based Activity Reporter of Kinase)in planta, based on phosphorylation-induced phase separation and confocal microscopy. We deployed SPARK in plants for thein vivomonitoring of SnRK1 kinase activity. With this tool, we obtained a comprehensive insight into the spatio-temporal dynamics on how SnRK1 regulates growth and development during plant life. For instance, real-time visualization of a growing root, further unveiled SnRK1’s circadian role, steering primary root elongation according to the availability of shoot derived carbohydrates. Based on the observed hotspots in SnRK1-SPARK activity, we applied Tissue Specific CRISPR KO to further investigate the essential role of SnRK1 during plant growth and development.

Urte Schlüter (Heinrich Heine University Düsseldorf, Germany)

u.schlueter@hhu.de

Carbon concentrating mechanisms enhance the carboxylase efficiency of the central photosynthetic enzyme rubisco by providing supra-atmospheric concentrations of CO2 in its surroundings. In the C4 photosynthesis pathway, this is achieved by considerable changes to the leaf biochemistry and anatomy. Carbon concentration by the photorespiratory glycine shuttle requires fewer and less complex modifications and could represent an early step during evolution from C3 to C4 photosynthesis. Physiology, biochemistry and anatomy were studied in a large variety of Brassicaceae and Asteraceae species representing several independent origins of carbon concentrating mechanisms. In the Brassicaceae, gradual reduction in the CO2 compensation points indicated considerable variation in the efficiency of the carbon concentrating pathway of the different plant species. The glycine shuttle was generally connected to centripetal organelle accumulation in the bundle sheath. Leaf biochemistry was only mildly affected by the photorespiratory shuttle but the C4 shuttle caused characteristic changes in the metabolite pattern. Association of leaf parameters with genetic features in the different can help to identify molecular mechanisms behind the evolution of the trait and possible targets for engineering approaches.

P2.18 THE PLANT TARGET

Thursday 6 July 2023 16:30

Christian Meyer (Institut Jean-Pierre Bourgin (IJPB) University Paris-Saclay INRAE AgroParis-Tech Versailles, France)

christian.meyer@inrae.fr

The eukaryotic Target of Rapamycin (TOR) kinase has a central role in adjusting growth and metabolism in response to both external and internal signals. Indeed, the TOR pathway controls essential biological outputs like mRNA translation, autophagy, metabolic adaptations and hormone responses, collectively contributing to growth and stress survival. Sugars are essential carbon and energy sources but also constitute signalling molecules which control many important biological processes. However, a great deal remains to be discovered about the molecular mechanisms and components of sugar sensing in plants. Here, I will present and discuss the complex links between sugar signalling and metabolism and the TOR kinase in plants. The availability of sugars, but also of nitrogen, strongly activates the TOR kinase activity. Moreover, there is mounting evidence from the literature and from our own results that several sugar-driven developmental, molecular or metabolic processes are controlled in a TOR-dependent manner. These processes include shoot and root growth, alterative splicing, gene expression, or starch, sucrose and raffinose synthesis. Recent results on the links between TOR activity, the vacuole, and cell growth will also be presented.

Thursday 6 July 2023 15:45

OF RAPAMYCIN KINASE: AN INSTRUCTOR FOR SUGAR SENSING, SIGNALLING AND METABOLISM.

P2.17 DIVERSITY OF LEAF CARBON CONCENTRATING MECHANISMS MEDIATED BY METABOLITE SHUTTLES

P2.19 TARGET OF RAPAMYCIN SIGNALLING COUPLES ANAEROBIC RESPONSES TO ENERGY STATUS IN ARABIDOPSIS

Thursday 6 July 2023 17:00

Alicja B Kunkowska (School of Advanced Studies Sant'Anna, Italy), Fabrizia Fontana (School of Advanced Studies

Sant'Anna, Italy), Federico Betti (School of Advanced Studies

Sant'Anna, Italy), Raphael Soeur (RWTH Aachen University, Germany), Gerold JM Beckers (RWTH Aachen University, Germany), Christian Meyer (IJPB INRAE Versailles, France), Geert De Jaeger (Ghent University, Belgium), Daan A Weits (Utrecht University, Netherlands), Elena Loreti (National Research Council, Italy), Pierdomenico Perata (School of Advanced Studies Sant'Anna, Italy)

alicja.kunkowska@santannapisa.it

During flooding, plants are exposed to low oxygen stress. Hypoxia activates expression of several genes, including those encoding for fermentation enzymes. As ATP production via the mitochondrial electron transport chain requires oxygen, plants activate ethanol and lactic fermentation to sustain glycolysis to provide a basal level of cellular energy. This requires the input of sugars and therefore carbon availability is crucial for survival in low oxygen conditions. However, the strength of the anaerobic response requires fine-tuning so it does not deplete the carbohydrates reserves of the plant before flooding recedes. This hypothesis is supported by the observation that plants subjected to sugar starvation under low oxygen conditions show a reduced expression of the hypoxia-inducible geneALCOHOL DEHYDROGENASE(ADH). However, the molecular mechanism that integrates sugar reserves and anaerobic response remained elusive. Remarkably, here we show that a chemical inhibition of TARGET OF RAPAMYCIN (TOR) reducesADHexpression regardless of sugar availability, indicating that active TOR is necessary for a proper hypoxic response. This was further confirmed with an estradiol-inducible TOR silencing line, in which repression ofADHwas comparable to the sugar starvation effect. Moreover, mutants of TOR complex show impaired tolerance to submergence. Finally, we identified two phosphorylation sites in RAP2.12 which are involved in the dampening of anaerobic response upon carbohydrate starvation and are targeted by TORin vitro. Taken together, we reveal a novel molecular mechanism behind the fine-tuning of anaerobic responses by plants’ energy status via TOR activity.

P2.20 SUGAR FEEDS INTO THE CYTOKININ PATHWAY TO REGULATE ROOT MERISTEM SIZE.

Thursday 6 July 2023 17:15

Marta Del Bianco (Italian Space Agency, Italy), Barry Causier (University of Leeds, United Kingdom), Benedetta Mattei (University of Aquila, Italy), Brendan Davies (University of Leeds, Italy), Paolo Costantino (Accademia dei Lincei, Italy), Sabrina Sabatini (University of Rome 'Sapienza', Italy)

marta.delbianco@asi.it

Plants produce sugar as an essential structural component and energy source, through the photosynthetic process. Leaves represent the main sugar source, while the growing root tip represents the main sugar sink. Plants have evolved mechanisms to respond to the carbon fluctuations caused by changes in photosynthetic efficiency by adjusting their growth and development. In this view, sugar acts as long-distance signalling molecule, coordinating root development with shoot fitness.

In the root meristem, stem cell daughter cells transiently proliferate in the proximal meristem, then stop dividing and begin to differentiate in a region known as the transition zone (TZ). The balance between cell proliferation and differentiation rates determines root meristem length and root growth. The differentiation of meristematic cell at the TZ is regulated by the hormone cytokinin through a cascade involving the transcription factor Arabidopsis Response Regulator 1 (ARR1). Sugar availability can regulate root meristem size, and here we suggest it does so by modulating cell differentiation via the ARR1 pathway. This crosstalk mediates the coordination between shoot activity and root growth.

P2.21 THE SIGNALLING METABOLITE TREHALOSE 6-PHOSPHATE IS A KEY SIGNAL IN THE REGULATION OF DEVELOPMENT

Thursday 6 July 2023 17:30

Franziska Fichtner (Heinrich Heine University Düsseldorf, Germany), Regina Feil (Max Planck Institute of Molecular Plant Physiology, Germany), John E Lunn (Max Planck Institute of Molecular Plant Physiology, Germany), Christine A Beveridge (ARC Centre for Plant Success in Nature and Agriculture and School of Biological Sciences, Australia)

franziska.fichtner@hhu.de

Trehalose 6-phosphate (Tre6P) is a sucrose specific signalling metabolite that has been implicated in the broad regulation of metabolism as well as developmental processes like flowering and shoot branching. Expressing tagged forms of TREHALOSE-6-PHOSPHATE SYNTHASE1 (TPS1), the main Tre6P-synthesizing enzyme in arabidopsis, revealed that Tre6P synthesis occurs predominantly in the vasculature and meristematic tissues of the whole plant. The vascular expression of TPS1 on both sides of the apoplastic barrier (in phloem parenchyma as well as in companion cells and sieve elements) ideally places Tre6P at the interface between source and sink and at a highly strategic site for systemic signalling of sucrose status. To test this potential of Tre6P as a hormone-like signal, we investigated the impact of localized changes in Tre6P levels in axillary buds and found that lowering Tre6P strongly inhibited bud growth. We further found that changing Tre6P levels in the vasculature modulated flowering and branching. These effects on plant development involve interaction with photoperiodic signalling, alteration in sucrose allocation, and interaction with strigolactone signalling. As phytohormone signalling components including cytokinin and strigolactones are also located in the vasculature, the vasculature may be considered as a hub for developmental decision making. Combinatorial mutant analyses, metabolic profiling and RNA sequencing approaches revealed multiple connections between Tre6P and other phytohormone signalling pathways, especially strigolactones, allowing us to place Tre6P signalling in the network of hormonal regulation of plant development.

P3 - LIFE AT THE INTERFACE - PLANT MEMBRANE-PROTEIN DYNAMICS AND INTERACTIONS DURING RESPONSES TO ENVIRONMENTAL CHANGE

P3.1 ABLS AND TMKS ARE CORECEPTORS FOR EXTRACELLULAR AUXIN

Tuesday 4 July 2023 09:00

Tongda Xu (Fujian Agriculture and Forestry University, China), Yongqiang Yu (Fujian Agriculture and Forestry University, China), Wenxin Tang (Fujian Agriculture and Forestry University, China), Wenwei Lin (Fujian Agriculture and Forestry University, China), Zhenbiao Yang (University of California Riverside, United States)

tdxu@sibs.ac.cn

Extracellular perception of auxin, an essential phytohormone in plants, has been debated for decades. Auxin binding protein 1 (ABP1) physically interacts with quintessential transmembrane kinases (TMKs) and was proposed to act as an extracellular auxin receptor, but its role was disputed because abp1 knockout mutants lack obvious morphological phenotypes. Here we identified two new auxin-binding proteins, ABL1 and ABL2, that are localized to the apoplast and directly interact with the extracellular domain of TMKs in an auxin-dependent manner. Furthermore, functionally redundant ABL1 and ABL2 genetically interact with TMKs and exhibit functions that are overlapping with those of ABP1 as well as independent of ABP1. Importantly, the extracellular domain of TMK1 itself binds auxin and synergizes with either ABP1 or ABL1 in auxin binding. Thus, our findings discovered new auxin receptors ABL1 and ABL2 having functions overlapping with but distinct from ABP1 and acting together with TMKs as co-receptors for extracellular auxin.

Clara Paola Igisch (Laboratoire Reproduction et Développement des Plantes (RDP), France), Vincent Bayle (Laboratoire Reproduction et Développement des Plantes (RDP) Lyon, France), Christine Miège (Laboratoire Reproduction et Développement des Plantes (RDP) Lyon, France), Yvon Jaillais (Laboratoire Reproduction et Développement des Plantes (RDP) Lyon, France)

clara.igisch@ens-lyon.fr

The plant hormone auxin is one of the most potent regulators of plant growth and architecture. Auxin signaling has several effects, including both regulation of gene expression, and fast “non-genomic” responses (1–15 min). Among other developmental functions, these fast auxin responses rapidly inhibit root cell elongation and control asymmetric growth upon perception of environmental stimuli, such as gravity (i.e. gravitropism). How auxin rapidly controls cellular functions is only partially understood but is in part regulated via the signaling activity of the Rho GTPase ROP6. We recently showed that exogenous auxin application rapidly triggers the clustering of ROP6 into nanodomains at the plasma membrane and that ROP6 nanoclustering is required for its function. In this talk, we will describe the dynamics of ROP6 nanoclustering following auxin treatment and during gravitropism. We will also discuss some of the molecular determinants required for ROP6 clustering, including components acting upstream in the auxin signaling pathway.

Tuesday 4 July 2023 09:30

Tuesday 4 July 2023 10:00

Wendy A Peer (University of Maryland, United States), Mark Jenness (University of Maryland, United States), Lillyanna House (University of Maryland, United States), Reuben Tayengwa (University of Maryland, United States), Anket Sharma (University of Maryland, United States), Bret Cooper (United States Department of Agriculture, United States), Angus Murphy (University of Maryland, United States)

P3.2 AUXIN-MEDIATED REGULATION OF RHO GTPASE DYNAMICS, NANOCLUSTERING AND SIGNALING AT THE PLANT PLASMA MEMBRANE

P3.3 AUXIN OXIDATION AT THE PLASMA MEMBRANE

ORGANISED BY: ANGUS MURPHY (UNIVERSITY OF MARYLAND), PIERS HEMSLEY (UNIVERSITY OF DUNDEE), WENDY PEER (UNIVERSITY OF MARYLAND)

wapeer@umd.edu

Oxidation of auxins has been an area of study for more than 70 years. Historically, both a membrane and a soluble oxidation activity were identified. In vitro studies in Arabidopsis showed that the enzyme DAO1 and its paralogue DAO2 could oxidize auxin to oxIAA, and recent studies have shown that soluble auxin-amino acid conjugates, such as IAAsp, are the DAO1 physiological substrates that are subsequently hydrolyzed to oxIAA. Here we present evidence that Arabidopsis DAO1 is associated with plasma membrane and cytosol, and that addition of auxin shifts DAO1 localization from the membrane in sucrose density fractionation. Further enzyme assays show that DAO1 substrate affinities differ with subcellular localization, with the membrane fraction exhibiting greater affinity for IAA and the soluble fraction for IAAsp. DAO2 is soluble and shows different substrate affinity. As temperature increases, so does auxin biosynthesis, suggesting that this mechanism to maintain auxin homeostasis becomes more important with climate change.

P3.4 THE ROLE OF GHR1 AND ITS INTERACTORS IN STOMATAL MOVEMENTS

Tuesday 4 July 2023 10:15

Maija Sierla (University of Helsinki, Finland),

N Valdebenito Alamar (University of Helsinki, Finland),

J Kemppinen (University of Helsinki, Finland),

TDG Nunes (University of Helsinki, Finland),

X Zarza (University of Helsinki, Finland),

R Haajanen (University of Helsinki, Finland),

A Huusari (University of Helsinki, Finland),

M Brosche (University of Helsinki, Finland),

J Kangasjärvi (University of Helsinki, Finland),

C Waszczak (University of Helsinki, Finland)

maija.sierla@helsinki.fi

Stomatal pores are responsible for plant gas exchange. They are formed on the leaf surface by two surrounding guard cells and simultaneously regulate and balance water loss with the uptake of carbon dioxide necessary for photosynthesis. Stomata are a primary site of interaction of the plant with its environment and have developed mechanisms to sense and respond to changing conditions. Adjustment of stomatal aperture is achieved by turgor changes resulting from ion transport across the guard cell plasma membranes. Ion channels and transporters are the primary targets of guard cell signalling networks and their activity determines the aperture of stomatal pores.

We have previously shown that the leucine-rich receptor-like kinase (LRR-RLK) GHR1 is a central regulator of stomatal closure. GHR1 is a pseudokinase that activates the guard cell anion channel SLAC1 and acts in stomatal closure through scaffolding functions rather than direct phosphorylation of target proteins. Given the severity and pervasive nature of stomatal phenotypes in ghr1 mutant plants, GHR1 may be an integration point where diverse endogenous and environmental signals converge to regulate components required for rapid stomatal closure. We have recently identified novel interactors of GHR1 through an interactomics approach and are currently characterizing the molecular details of the interactions in order to gain understanding of how these interaction networks regulate stomatal movements. Our data indicates that in addition to SLAC1, the GHR1 complex contains other guard cell channels, transporters and LRR-RLKs.

P3.5 A CONCEPTUAL FRAMEWORK FOR THE NANOSCALE REGULATION OF CELL-SURFACE RECEPTOR COMPLEXES.

Tuesday 4 July 2023 13:30

Julien Gronnier (ZMBP University of Tuebingen, Germany), Michelle Von Arx (ZMBP University of Tuebingen, Germany), Kaltra Xhelilaj (ZMBP University of Tuebingen, Germany)

julien.gronnier@zmbp.uni-tuebingen.de

Sensing of self, non-self, and modified-self molecules by cell surface receptors plays preponderant roles in regulating all aspects of plants life. Receptor kinases (RKs) are main ligand-binding cell surface receptors sensing and relaying signals at the cell surface. RKs forms ligandinduced complexes to initiate signaling events. For instance, upon perception of bacterial flagellin, the ligand-binding receptor FLS2 associates with its co-receptor BAK1 to initiate immune signaling. While the genetic and structural bases underlying ligand-induced formation of receptor complexes for archetypical signaling pathways is well documented, how within the plasma membrane their associations are regulated in space and time remain enigmatic. We used live cell imaging approaches, such as variable-angle total internal fluorescence microscopy, single-particle tracking, to analyse the organization and dynamics of FLS2 and BAK1 within the plasma membrane. We observed that the conditional association between FLS2 and BAK1 follows a defined and generalizable spatial and temporal logic. We propose a conceptual framework for the nanoscale regulation of receptor complexes which open ways toward the identification of the underlying regulatory mechanisms.

P3.6 EVOLUTION AND FUNCTION OF RECEPTOR-LIKE KINASES IN ARBUSCULAR MYCORRHIZAL SYMBIOSIS

Tuesday 4 July 2023 14:00

Chai Hao Chiu (University of Cambridge, United Kingdom), Uta Paszkowski (University of Cambridge, United Kingdom) chc59@cam.ac.uk

Evolution of symbiosis with arbuscular mycorrhizal fungi (AMF) was one of the key innovations that enabled the successful conquest of land plants. In this mutually beneficial symbiosis, fungi-delivered mineral nutrients are exchanged for plant photosynthates in elaborate, highlybranched structures called arbuscules. To detect micro-organisms and non-self molecules, plants have a complex immune surveillance system including receptor kinases located on the plasma membrane. However, it is not clear how the early detection of the symbiotic fungus leads to appropriate signal transduction, as well as the types of signals and receptors involved in the processes that initiate, maintain and sustain this symbiosis. At the same time, signalling activated by the fungus also reprogrammes plant root development to produce more lateral roots, resulting in increased surface area for symbiotic interactions. We discovered that a diverse set of plant receptors are involved in symbiosis establishment, as well as a conserved signal-receptor system in activating lateral organ formation in response to chitinderived molecules. Tracing the evolution of these receptors in the green lineage also revealed insights on the origins and deep conservation of their symbiosis signalling functions early in land plant evolution. I will also discuss ongoing work to elucidate the signal transduction cascades downstream of the receptor kinases.

P3.7 ACTIVATION AND REGULATION OF NITROGEN TRANSPORTERS IN PLANTS DURING ARBUSCULAR MYCORRHIZAL SYMBIOSIS

Tuesday 4 July 2023 14:30

Guohua Xu (Nanjing Agricultural University, China), Shunan Zhang (Nanjing Agricultural University, China), Kangning Li (Nanjing Agricultural University, China), Yuyi Zhang (Nanjing Agricultural University, China), Ying Liu (Nanjing Agricultural University, China)

ghxu@njau.edu.cn

Nitrogen use efficiency (NUE) is critical for the sustainable development of agricultural production. Plant NUE as an inherently complex, including N uptake, translocation, assimilation, and remobilization, is governed by multiple interacting genetic and environmental factors. We found that a circadian clock regulator, N-mediated heading date 1 (Nhd1), is a key integrator to coordinate growth duration and N utilization in rice. Nhd1 directly activates the transcription ofOsSUT1for sucrose distribution andOsAMT1;3together withOsNRT2.4to modulate root growth and N uptake, meanwhile it suppresses the activity of FdGOGAT for assimilation of amnio acids in response to different N supplies. The physiological and genetic studies further provide the evidence of Nhd1 acting as an upstream regulator of these transporters and enzyme. Interestingly, Nhd1 also triggers the expression of floral geneOsHd3ato promote flowering in rice. Inactivation of eitherNhd1orOsHd3aresults in a delay and insensitivity to N-responsive flowering time. Accordingly,nhd1mutants accumulated more N and achieved a higher N uptake efficiency (NUpE) due to the delayed flowering time and prolonged growth duration under low N availability. Surprisingly, enhancing endogenous expression of Nhd1 improves rice eating and cooking quality without altering entire growth duration and NUE. Taking together, our study reveals that circadian clock component Nhd1 plays an important role in modulating NUE to meet the fluctuating N demand during the growth period of rice.

P3.8 PMI1 NT-C2 DOMAIN BINDS PHOSPHOLIPIDS AND IS CRUCIAL FOR PMI1 MEMBRANE LOCALISATION

Tuesday 4 July 2023 14:45

Dominika Cieslak (Institute of Biochemistry and Biophysics Polish Academy of Sciences, Poland), Grazyna Dobrowolska (Institute of Biochemistry and Biophysics Polish Academy of Sciences, Poland), Olga Sztatelman (Institute of Biochemistry and Biophysics Polish Academy of Sciences, Poland)

dominikacieslak@ibb.waw.pl

PMI1 is a plant specific protein involved in light directed chloroplast movement. The protein takes part both in reaction to high-intensity blue light – avoidance response – and to low-intensity blue light –accumulation response. Recently, it has been shown that PMI1 localises to the plasma membrane and relocates within it in response to blue light. Such localisation seems to be crucial for the protein role in chloroplast movement. PMI1 contains NT-C2 (N-terminal C2) domain, which is a member of C2 domain family. Those domains are second most abundant lipid binding domains in eukaryotes, right after PH domains. Most of them bind lipids in calcium dependent manner. However,

for PMI1 NT-C2 domain lipid binding was not confirmed to date.

In this study we examined PMI1 NT-C2 domain intracellular localisation both in control and stress conditions. We identify regions essential for its localisation to the plasma membrane. Using recombinant protein we showed that PMI1 NT-C2 domain binds phospholipids specifically present in the plasma membrane. Calcium ions did not affect the binding. Those in vitro results were confirmed in planta by microscopic observations of the domain co-localisation with phospholipid markers. What is more, in salt stress both full length PMI1 and NT-C2 domain as well as phospholipid markers were relocated into punctuate structures – co-localisation occurred.

The above results indicate that NT-C2 domain of PMI1 is responsible for localisation of the protein. NT-C2 domain allows PMI1 to bind plasma membrane by interacting with membrane-residing lipids in calcium independent manner.

P3.9 A PECTIN-BINDING RALF PEPTIDE WITH BOTH A STRUCTURAL AND SIGNALING ROLE IN THE PERIODIC ASSEMBLY OF THE PLANT CELL WALL

Tuesday 4 July 2023 15:30

Kris Vissenberg (Integrated Molecular Plant Physiology Research group University of Antwerp Antwerp, Belgium), Sébastjen Schoenaers (Integrated Molecular Plant Physiology Research group University of Antwerp Antwerp, Belgium), Francis Lee (Plant Signaling Mechanisms Laboratory University of Lausanne Lausanne, Switzerland), Martine Gonneau (Université Paris-Saclay INRAE

AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France), Thomas Levasseur (Biopolymeres Interactions and Assemblages (BIA) INRAE Nantes, France), Elvina Faucher (Université Paris-Saclay INRAE AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France), Elodie Akary (Université Paris-Saclay INRAE AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France), Kalina Haas (Université Paris-Saclay INRAE AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France), Naomi Claeijs (Integrated Molecular Plant Physiology Research group University of Antwerp Antwerp, Belgium), Steven Moussu (Plant Signaling Mechanisms Laboratory University of Lausanne Lausanne, Switzerland), Caroline Broyart (Plant Signaling Mechanisms Laboratory University of Lausanne Lausanne, Switzerland), Thierry Desprez (Université ParisSaclay INRAE AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France), Celine Moreau (Biopolymeres Interactions and Assemblages (BIA) INRAE Nantes, France), Estelle Bonnin (Biopolymeres Interactions and Assemblages (BIA) INRAE Nantes, France), Daniel Santa Cruz Damineli (Department of Cell Biology and Molecular Genetics University of Maryland College Park MD 20742-58, United States), Alex Costa (Department of Biosciences University of Milano Milan, Italy), Jose A Feijo (Department of Cell Biology and Molecular Genetics University of Maryland College Park MD 20742-58, United States), Bernard Cathala (Biopolymeres Interactions and Assemblages (BIA) INRAE Nantes, France), Julia Santiago (Plant Signaling Mechanisms Laboratory University of Lausanne Lausanne, Switzerland), Herman Höfte (Université Paris-Saclay INRAE AgroParisTech Institut Jean-Pierre Bourgin (IJPB) Versailles, France)

kris.vissenberg@uantwerpen.be

Secreted Rapid ALkalinization Factor (RALF) peptides have emerged as key components controlling cell wall integrity. However, the inner workings of the RALF pathway remain enigmatic. Here we show that RALF22, a root hair expressed RALF, has a dual signaling and structural role during cell growth. RALF22 loss-of-function root hairs are short and frequently burst due to loss of wall integrity. Exogenous RALF22 treatment induces a FERONIA-dependent root hair growth arrest and a FER-independent increase in cell wall porosity. Our data show that this duality is the result of RALF22 interacting with (1) the LLG1/FER transmembrane receptor complex to regulate downstream signaling and (2) the integral cell wall proteins LRX1 and LRX2 to regulate pectic cell wall assembly. In the root hair cell wall, RALF22 forms periodic circumferential rings which colocalize with rings of block-wise demethylated homogalacturonan (HG) and LRX1. Polycationic RALF22 and RALF22-LRX1 bind to and induce the condensation of polyanionic HG in a charge dependent manner.In vivo, the LLG1-RALF22-FER and RALF22-LRX1-pectin interactions are mutually exclusive. We propose a new mechanism in which RALF22 simultaneously regulates periodic pectin assembly through LRX1/2 and cell wall sensing through LLG1/FER.

P3.10 GREASING SIGNALLING IN PLANTS - THE ROLE OF POSTTRANSLATIONAL

S-ACYLATION IN RECEPTOR KINASE FUNCTION

Tuesday 4 July 2023 16:00

Piers A Hemsley (University of Dundee and The James Hutton Institute, United Kingdom), Charlotte H Hurst (University of Dundee and The James Hutton Institute, United Kingdom), Dionne Turnbull (University fo Dundee, United Kingdom), Kaltra Xhelilaj (ZMBP Universität Tübingen, Germany), Sally M Myles (University fo Dundee, United Kingdom), Julien Gronnier (ZMBP Universität Tübingen, Germany)

p.a.hemsley@dundee.ac.uk

Receptor kinases are proteins that act as the primary means by which plants perceive physical signals in their extracellular environment. This includes pathogenic and beneficial microbes, the state of the plant’s own cell wall and various plant hormones. As a result, receptor kinases are critical to controlling how plants balance resource allocation during growth, trading resistance to pathogens against seed yield or vegetative productivity. Given their powerful ability to control and balance how plants respond to their environment it is no surprise that they are very tightly regulated and controlled. We recently demonstrated that receptor kinases are post-translationally modified by fatty acids (S-acylation) at a site conserved in all receptor kinases making S-acylation a likely universal mode of regulation. S-acylation appears to stabilise activated receptor complexes and delay receptor endocytosis to promote sustained signalling from the plasma membrane. These data provide key insights into how receptor kinase signalling is likely amplified, sustained and attenuated in all plant species. We will discuss our findings in the context of recent literature to propose a model of how receptor kinases are functionally regulated and organised at the plasma membrane during signalling and signal attenuation.

P3.11 STUDYING THE FUNCTIONALITY OF CASSAVA MEPAT14 THROUGH COMPLEMENTATION ASSAYS AND CRISPR/CAS9 KNOCKOUTS

Tuesday 4 July 2023 16:30

Kyle D Tyler (Liverpool John Moores University, United Kingdom), Baoxiu Qi (Liverpool John Moores University, United Kingdom), Si Gu (Liverpool John Moores University, United Kingdom)

K.d.tyler@2019.ljmu.AC.uk

Cassava is a vital food source for over 800 million people globally, but long growth cycles and susceptibility to devastating pathogens reduced its availability. Our previous study of the Protein S-Acyltransferase 14, AtPAT14 in the model plant Arabidopsis showed that disruption of this gene in the mutant plants can result in maturity hence reduced growth cycle by 40%. This is due to the elevation of salicylic acid (SA) content and expression levels of genes involved in the SA synthesis and signalling pathway, leading to accelerated senescence. Interestingly, the phenotype of the atpat14 k/o mutants resemble to those disease resistant mutants. This led us believe that AtPAT14 may play roles in disease response. AtPAT14 belongs to the PAT family including 24 PATs in Arabidopsis that play critical roles in growth, development, reproduction, and stress. Using AtPAT14 as a query we identified 34 MePAT14 homologs from the recently fully sequenced cassava genome. The two most similar MePAT14 homologs were then used to assess whether they function similarly to AtPAT14 by complementation assays in yeast and Arabidopsis. We show that they both can rescue the growth defect of yeast PAT mutant akr1 and Arabidopsis AtPAT14 mutant atpat14, indicating they are indeed functional PAT14 of cassava. Future work will involve generating Cassava MePAT14 knockouts using the CRISPR/Cas9 system and characterizing their genotype and phenotype, including growth and yield assessment of the CRISPR/ Cas9-edited plants. This research provides a valuable foundation for developing new cassava cultivars that mature faster and are more resistant to diseases.

P3.12 MOLECULAR MECHANIMS OF REGULATION AND ION SELECTIVITY OF PLANT GLUTAMATE-RECEPTORS

Wednesday 5 July 2023 09:00

Jose A Feijo (University of Maryland, United States)

jfeijo@fc.ul.pt

Plant Glutamate Receptors (GLRs) are ion channels which are increasingly recognised as crucial for a number of cell-cell communication processes involved in relevant functions, such as reproduction and development, host-pathogen interaction, long-distance communication, wound repair, etc.. In contrast, progress in understanding their molecular features relevant for these roles is lagging. I will present new data regarding their sub-unit polymerization and interactions with other proteins, ligand and ion specificity and propose new modes of action that should inform proper genetic screen design for asserting their function in vivo.

P3.13 LONG-DISTANCE TURGOR PRESSURE CHANGES INDUCE LOCAL ACTIVATION OF PLANT GLUTAMATE RECEPTOR-LIKE CHANNELS

Wednesday 5 July 2023 09:30

Alex Costa (University of Milan, Italy)

alex.costa@unimi.it

In Arabidopsis thaliana, local wounding and herbivore feeding provoke leaf-to-leaf propagating Ca2+ waves that are dependent on the activity of members of the glutamate receptor-like channels (GLRs). In systemic tissues, GLRs are needed to sustain the synthesis of jasmonic acid (JA) with the subsequent activation of JA-dependent signalling response required for the plant acclimation to the perceived stress. Even if the role of GLRs is well established, the mechanism through which they are activated remains unclear. Here we report that in vivo the amino aciddependent activation of the AtGLR3.3 channel and systemic responses require a functional ligand-binding domain. By combining imaging and genetics we show that leaf mechanical injury, such as wound, burn as well as hypo-osmotic stress in root cells induce the systemic apoplastic increase of L-Glutamate which is largely independent of AtGLR3.3 that is instead required for systemic cytosolic Ca2+ elevation. Moreover, by using a bioelectronic approach we show that the local release of minute concentrations of L-Glutamate in the leaf lamina fails to induce any long-distance Ca2+ waves.

P3.14 ROLE AND POST-TRANSLATIONAL REGULATION OF NADPH OXIDASESMEDIATED ROS SIGNALING IN MITOCHONDRIAL DYSFUNCTION RESPONSE

Wednesday 5 July 2023 10:00

Alexis PORCHER (University of Helsinki, Finland), Julia Vainonen (University of Helsinki, Finland), Matteo Citterico (University of Helsinki, Finland), Michael Wrzaczek (Institute of Plant Molecular Biology, Czech Republic), Saijaliisa Kangasjärvi (University of Helsinki, Finland)

alexis.porcher@helsinki.fi

Reactive oxygen species (ROS) are essential signaling molecules that are needed for rapid establishment of stress responses in plants. Mitochondria have an important function in the maintenance of cellular redox balance, as they act both as a source and sensor for ROS and form a major hub for ROS signal integration between different cellular compartments. Tight ROS signal integration is necessary to coordinate the mitochondrial dysfunction response involved in plant defense and stress resilience mechanisms. The plasma membrane-localized NADPH oxidases (RBOHs) produce ROS in the apoplast and initiate ROS signaling cascades in response to various abiotic and biotic stresses. However, unravelling the post-translational regulatory mechanisms that control RBOH activity and its integration with mitochondrial stress signaling calls for further investigation. We aim to combine Arabidopsis genetic toolkits, subcellular ROS quantification using ROS sensors lines, proximity labeling proteomics and targeted phosphoproteomic, and analysis of RBOH activity in human cell lines to characterize the role

of RBOH in mitochondrial dysfunction responses. Our recent findings suggest a new protein phosphatase 2A (PP2A)-mediated mechanisms for direct posttranslational regulation of RBOH and ROS signaling. This will elaborate ROS signal integration between RBOH and mitochondria, which seems essential for plant defense and stress recovery reactions. With this, we aim to forward the holistic understanding of plant stress resistance and open new opportunities for engineering resilience in crop species.

P3.15 THE ROLE OF AUXIN EFFLUX, CONJUGATION AND OXIDATION DURING APICAL HOOK OPENING

Wednesday 5 July 2023 11:00

Angus S Murphy (University of Maryland, United States), Mark Jennes (University of Maryland, United States)

asmurphy@umd.edu

Dicotyledonous plants form an apical hook after germination to protect apical tissues as the seedling navigates through soil to light. Differential distribution of the phytohormone auxin via PIN efflux carriers regulates asymmetric cell expansion during hook development. Results presented herein indicate that auxin levels in established apical hooks are initially low and increase during opening consistent with activation of PIN-mediated efflux. The kinetics of auxin accumulation and metabolism demonstrate an additional role of ABCB auxin efflux transporters and auxin conjugation/oxidation enzymes in reduction of cellular auxin levels on the concave side of the hook during an ~20 h maintenance interval. Oxidized auxin appears to actively contribute to hook maintenance under low auxin conditions by enhancing IAA7TIR1 interactions while inhibiting IAA7 degradation. The results presented establish a model in which asymmetric growth established during hook formation is maintained by temporary reduction of auxin levels on the concave side and suggest that models suggesting ABCB export of brassinosteroids to the outer leaflet of the plasma membrane contributes to apical hook maintenance.

P3.16 RAB PRENYLATION HIERARCHY IN PLANTS

Wednesday 5 July 2023 11:30

Małgorzata Gutkowska (Warsaw University of Life Sciences Institute of Biology, Poland), Marcin Gradowski (Warsaw University of Life Sciences Institute of Biology, Poland), Joanna Szewińska (Warsaw University of Life Sciences Institute of Biology, Poland), Michal Hala (Charles University in Prague Faculty of Science, Czech Republic), Martina Klejchova (Charles University in Prague Faculty of Science, Czech Republic), Maria Winiewska-Szajewska (Institute of Biochemistry and Biophysics Polish Academy of Lice Sciences, Poland), Marta Hoffman-Sommer (Institute of Biochemistry and Biophysics Polish Academy of Lice Sciences, Poland)

gosiagut77@gmail.com

Rab proteins are small GTP-ases engaged in vesicular transport in all Eukaryotic cells. In Arabidopsis, there are 57 Rab proteins divided into

eight sub-families. To perform their function in budding, fusion and directional movement of a vesicle all Rab proteins must be modified by lipid geranylgeranyl groups. This posttranslational modification is introduced by an enzyme Rab Geranylgeranyl Transferase (RGT), built of three components: catalytic α-subunit (RGTA), lipid substrate binding β-subunit (RGTB), and Rab Escort Protein (REP). Here we present preliminary data on the affinity of Rab proteins from distinct sub-families towards REP obtained by in vivo and in vitro experiments and in silico modeling. The most abundant Rab proteins in Arabidopsis etiolated hypocotyl are Rab proteins from the Rab D family, engaged in early secretory transport events. RabD proteins are also the most vulnerable to RGT activity decrease as they delocalize from membranes to the cytoplasm in the rgtb1 mutant. RabD1 binding constant to REP was estimated to be 7 μM in vitro. On the other side of the scale are ubiquitous RabG proteins engaged in endocytic transport to vacuoles. Rab G proteins are less vulnerable to the RGT activity decrease in the rgtb1 mutant. They bind to REP with higher affinity in vitro. By comparison of experimental data with the protein complex models we discuss the possible reason for the differences.

P3.17 A POINT MUTATION IN PSBW ABOLISHES THYLAKOID MEMBRANE ORGANIZATION.

Wednesday 5 July 2023 11:45

Tongda Xu (Fujian Agriculture and Forestry University, China), Yongqiang Yu (Fujian Agriculture and Forestry University, China), Wenxin Tang (Fujian Agriculture and Forestry University, China), Wenwei Lin (Fujian Agriculture and Forestry University, China), Zhenbiao Yang (University of California Riverside, United States) theresa.ilse@biol.ethz.ch

A genetic screen using EMS-mutagenized Arabidopsis plants to identify players of starch granule biogenesis revealed a mutant with aberrant thylakoid membranes. The causative mutation (psbw2) lies in PsbW and introduces a single amino acid substitution (glycine to arginine) in the encoded protein’s single transmembrane helix. PsbW, a thylakoid membrane protein and component of the Photosystem II (PSII) – Light Harvesting Complex II (LHCII) –complex, is thought to stabilize the supramolecular formation of PSII, thereby optimizing the absorption and utilization of light energy.

Chloroplasts of psbw-2 show drastic alterations in thylakoid organization compared to wild types and presumably produce abnormal starch as a consequence. The thylakoid membranes no longer form distinct grana stacks, are not well aligned, and the lumen is substantially enlarged. Interestingly, the abnormal thylakoid structure and altered starch granule shape were not observed in the previously described PsbW knock-out (psbw-1). Both psbw-1 and psbw-2 mutants grow normally under normal growth-room conditions.

Here, I will present both psbw mutant phenotypes and elaborate on the potential action of the mutant protein in psbw-2. My findings thus far suggest that the substitution in psbw-2 alters the protein's interaction with other thylakoid membrane components, thereby causing the observed phenotype. I will discuss future approaches to investigate the underlying mechanisms, including proteinprotein interaction studies, subcellular localization analyses, and measurements of photosynthetic parameters. These data will help to better understand the molecular mechanisms involved in establishing thylakoid membrane organization and its importance for efficient photosynthetic metabolism.

P3.18 CHARACTERIZATION OF DIPLOSPORY IN TARAXACUM OFFICINALE L.: THE MISSING GENE FOR PLANT BREEDING

Wednesday 5 July 2023 12:00

Letizia Cornaro (Università degli Studi di Milano, Italy), Mara Cucinotta (Università degli Studi di Milano, Italy), Rosanna Petrella (Università degli Studi di Milano, Italy), Camilla Banfi (Università degli Studi di Milano, Italy), Vicente Balanzá (Università degli Studi di Milano, Italy), Peter J. Van Dijk (KeyGene N.V., Netherlands), Diana Rigola (KeyGene N.V., Netherlands), Rik H.M. Op den Camp (KeyGene N.V., Netherlands), Tatyana Radoeva (KeyGene N.V., Netherlands), Arjen J. Van Tunen (KeyGene N.V., Netherlands), Lucia Colombo (Università degli Studi di Milano, Italy)

letizia.cornaro@unimi.it

Diplospory is a type of apomictic reproduction characterized by the lack of a proper meiotic process, which results in the generation of an unreduced egg cell that develops into an embryo by parthenogenesis. Therefore, diplosporous plants produce a clonal progeny identical to the mother. The introduction of this system in sexually reproducing crops could have a huge impact on the ability to fix valuable and complex traits in plant breeding programs. Taraxacum officinale L., the common dandelion, is characterized by sexual diploid and apomictic polyploid genotypes. The analysis of a loss-of-diplospory mutant, generated by gamma-irradiation from a 3x apomictic plant, revealed a reversion to normal meiosis. This mutant allowed the identification of the putative DIPLOSPORY locus that controls the trait in dandelions. One of the genes present in the locus and gene for the regulation of diplospory is VACUOLAR PROTEIN SORTING-ASSOCIATED 13 (VPS13). The VPS13 gene family is conserved across all eukaryotes and encodes large proteins involved in the tethering between different organelles to transfer lipids within the cell. These proteins are well studied in humans and yeast, but there is scarce information about VPS13 in plants. Here, we characterize the role of AtVPS13S, one of the homologs identified in Arabidopsis, during female germline progression and a possible involvement of microRNA in this process.

P3.19 EXPLORING PLASMA MEMBRANE DYNAMICS AND ORGANIZATION AT THE NANOSCALE USING VA-TIRF AND SUPER-RESOLUTION MICROSCOPY.

Wednesday 5 July 2023 15:00

Julien Gronnier (University of Tübingen, Germany)

julien.gronnier@zmbp.uni-tuebingen.de

Super-resolution microscopy enables the observation of cellular structures with unprecedented details. Indeed, super-resolution microscopy circumvents light diffraction limit, a physical barrier that restricts the optical resolution to approximately 250 nm and was previously thought to be impenetrable. I will discuss advantages and limitations of variable-angle total internal reflection fluorescence microcopy (VA-TIRFM)-based approaches such as single particle tracking photoactivated localization microscopy (sptPALM) to observe and characterize molecules dynamics and organization at the nanoscale in living plant cells.

P3.20 NOVEL METHODS FOR MEMBRANE PROTEIN EXTRACTION AND CHARACTERISATION

Wednesday 5 July 2023 15:30

Piers A Hemsley (University of Dundee and The James Hutton Institute, United Kingdom), Silu Li (University of Dundee and The James Hutton Institute, United Kingdom), Charlotte H Hurst (University of Dundee, United Kingdom)

p.a.hemsley@dundee.ac.uk

Characterisation of membrane proteins and their complexes has traditionally been hampered by the necessity of membrane solubilisation and extraction. Classical detergent based methods disrupt membrane structure and differentially solubilise proteins, resulting in non-representative, or even artefactual, assessment of protein complexes. Recent developments in the field of structural biology have provided a range of membrane disrupting reagents able to preserve MDa sized complexes in their native lipid environment. Here I will discuss our preliminary work bringing these reagents to the biochemical, proteomic and lipidomic study of membrane protein complexes in plants, focussing on receptor kinases as model examples.

P3.21 PRODUCTION OF RECOMBINANT ARABIDOPSIS LEGUME LECTIN-LIKE PROTEINS IN PICHIA PASTORIS FOR FUNCTIONAL ANALYSIS

Wednesday 5 July 2023 15:45

Md Shahran Ahmed Nayem (University of Bayreuth, Germany), Corina Vlot Schuster (University of Bayreuth, Germany)

shahran.nayem@uni-bayreuth.de

Plants fend off pathogen invasions through a signaling network-based immune system. Systemic Acquired Resistance (SAR) is an inducible defense system against a broad spectrum of (hemi-) biotrophic pathogens and is regulated by a complex biomolecular network. Plant lectins contain carbohydrate-binding domain that helps them to recognize specific glycans from endogenous and exogenous sources.

Arabidopsis LEGUME LECTIN LIKE PROTEINs (LLP1, LLP2 and LLP3) belong to the lectin superfamily and are found in apoplast extract during SAR establishment. Both LLP1 and LLP3 are essential for SAR acting downstream of the recognition of long-distance defence signals. To unravel the molecular mechanism of the LLP function in SAR, we aimed to produce recombinant LLP protein in Pichia pastoris yeast. We designed 10 consensus sequences and added them to the target genes to characterize their efficiency in recombinant LLP production. We have found that the expression level of the LLPs in P. pastoris largely depends on the presence of specific consensus sequences in the target gene. Modification of certain nucleotides in the consensus sequences regulates the recombinant protein production competence. Similarly, the expression of recombinant LLPs was influenced by the pH of the culture media. However, the position of the tag in the recombinant proteins did not affect the expression. In summary, we were able to express the recombinant LLP in P. pastoris and concurrently defined the efficacy of our designed consensus sequences in recombinant LLP production. Future experimental applications that are planned with the recombinant proteins will be discussed

P3.22 GLOWING PHYTOCHROME: FOLLOWING PHYA DYNAMICS THROUGH BIOLUMINESCENCE

Wednesday 5 July 2023 16:00

Marissa Valdivia Cabrera (University of Edinburgh, United Kingdom), Karen J. Halliday (University of Edinburgh, United Kingdom)

s1886928@ed.ac.uk

Several high throughput methods to study Arabidopsis gene expression at transcriptional, post-transcriptional and post-translational levels have been developed during the past years. These methodologies provide important information that aid in our mechanistic understanding of molecular signalling. Nevertheless, most of these techniques present some disadvantages, including destructive sampling, signal saturation, discrete processing and present semi-quantitative results. Bioluminescent tags (e.g. luciferases, LUC) have emerged as a sensitive and reliable method to measure gene expression dynamics in vitro and in vivo. The activity of PHYA promoter and transcript have already been determined using the P. pyralis firefly LUC reporter enzyme (PHYAp:LUC), which have greatly assisted in space-time patterns of gene expression. However, LUC lines cannot be employed as protein reporters in planta due to LUC rapid inhibition by product, large size, and stability issues. Nano Luciferase (NLUC), an engineered stable-active O. gracilirostris crustacean LUC, can help overcome these issues and facilitate the study of dynamic protein stability in planta. Using the Mobius cloning system, we have generated PHYA-NLUC protein fusion constructs. Homozygous segregants were selected and phenotypically characterised for the creation of functional transgenic lines. These lines have allowed us to assess in-vivo dynamical behaviour of phyA module components for the first time. Results display the expected phyA’s diurnal rhythm, catching the protein’s proteolysis in exposure to white light and increased levels in response to far-red light. Further, this non-invasive, highly sensitive, and real-time resolution technology raises the opportunity to obtain dynamic quantitative data of other related Arabidopsis photoreceptors at native expression levels.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

P3.23 GREASING RECEPTOR KINASE SIGNALLING IN PLANTS

Wednesday 5 July 2023 POSTER SESSION

Charlotte H Hurst (University of Dundee, United Kingdom), Dionne Turnbull (University of Dundee, United Kingdom), Kaltra Xhelilaj (ZMBP Universität Tübingen, Germany), Sally M Myles (University of Dundee, United Kingdom), Julien Gronnier (ZMBP Universität Tübingen, Germany), Piers A Hemsley (University of Dundee and The James Hutton Institute, United Kingdom)

c.h.z.hurst@dundee.ac.uk

Receptor kinases are proteins that act as the primary means by which plants perceive physical signals in their extracellular environment. This includes pathogenic and beneficial microbes, the state of the plant’s own cell wall and various plant hormones. As a result, receptor kinases are critical to controlling how plants balance resource allocation during growth, trading resistance to pathogens against seed yield or vegetative productivity. Given their powerful ability to control and balance how plants respond to their environment it is no surprise that they are very tightly regulated and controlled. We recently demonstrated that receptor kinases are post-translationally modified by fatty acids (S-acylation) at a site conserved in all receptor kinases making S-acylation a likely universal mode of regulation. S-acylation appears to stabilise activated receptor complexes and delay receptor endocytosis to promote sustained signalling from the plasma membrane. These data provide key insights into how receptor kinase signalling is likely amplified, sustained and attenuated in all plant species.

P3.24 CHARACTERIZATION OF DIPLOSPORY IN TARAXACUM OFFICINALE L.: THE MISSING GENE FOR PLANT BREEDING

Wednesday 5 July 2023

POSTER SESSION

Letizia Cornaro (University of Milan, Italy), Mara Cucinotta (University of Milan, Italy), Rosanna Petrella (University of Milan, Italy), Camilla Banfi (University of Milan, Italy), Vicente Balanzá (University of Milan, Italy),

Peter J. Van Dijk (KeyGene N.V., Netherlands),

Diana Rigola (KeyGene N.V., Netherlands),

Rik H.M. Op den Camp (KeyGene N.V., Netherlands),

Tatyana Radoeva (KeyGene N.V., Netherlands),

Arjen J. Van Tunen (KeyGene N.V., Netherlands), Lucia Colombo (University of Milan, Italy)

letizia.cornaro@unimi.it

Diplospory is a type of apomictic reproduction characterized by the lack of a proper meiotic process, which results in the generation of an unreduced egg cell that develops into an embryo by parthenogenesis. Therefore, diplosporous plants produce a clonal progeny identical to the mother. The introduction of this system in sexually reproducing crops could have a huge impact on the ability to fix valuable and complex traits in plant breeding programs. Taraxacum officinale L., the common dandelion, is characterized by sexual diploid and apomictic polyploid genotypes. The analysis of a loss-of-diplospory mutant, generated by gamma-irradiation from a 3x apomictic plant, revealed a reversion to normal meiosis. This mutant allowed the identification of the putative DIPLOSPORY locus that controls the trait in dandelions. One of the genes present in the locus and gene for the regulation of diplospory is VACUOLAR PROTEIN SORTING-ASSOCIATED 13 (VPS13). The VPS13 gene family is conserved across all eukaryotes and encodes large proteins involved in the tethering between different organelles to transfer lipids within the cell. These proteins are well studied in humans and yeast, but there is scarce information about VPS13 in plants. Here, we characterize the role of AtVPS13S, one of the homologs identified in Arabidopsis, during female germline progression and a possible involvement of microRNA in this process.

P3.26 STUDYING THE FUNCTIONALITY OF CASSAVA MEPAT14 THROUGH COMPLEMENTATION ASSAYS AND CRISPR/CAS9 KNOCKOUTS

Wednesday 5 July 2023 POSTER SESSION

Kyle D. Tyler (Liverpool John Moores University, United Kingdom), Baoxiu Qi (Liverpool John Moores University, United Kingdom), Si Gu (Liverpool John Moores University, United Kingdom)

K.d.tyler@2019.ljmu.AC.uk

Cassava is a vital food source for over 800 million people globally, but long growth cycles and susceptibility to devastating pathogens reduced its availability. Our previous study of the Protein S-Acyltransferase 14, AtPAT14 in the model plant Arabidopsis showed that disruption of this gene in the mutant plants can result in maturity hence reduced growth cycle by 40%. This is due to the elevation of salicylic acid (SA) content and expression levels of genes involved in the SA synthesis and signalling pathway, leading to accelerated senescence. Interestingly, the phenotype of the atpat14 k/o mutants resemble to those disease resistant mutants. This led us believe that AtPAT14 may play roles in disease response. AtPAT14 belongs to the PAT family including 24 PATs in Arabidopsis that play critical roles in growth, development, reproduction, and stress. Using AtPAT14 as a query we identified 34 MePAT14 homologs from the recently fully sequenced cassava genome. The two most similar MePAT14 homologs were then used to assess whether they function similarly to AtPAT14 by complementation assays in yeast and Arabidopsis. We show that they both can rescue the growth defect of yeast PAT mutant akr1 and Arabidopsis AtPAT14 mutant atpat14, indicating they are indeed functional PAT14 of cassava. Future work will involve generating Cassava MePAT14 knockouts using the CRISPR/Cas9 system and characterizing their genotype and phenotype, including growth and yield assessment of the CRISPR/Cas9-edited plants. This research provides a valuable foundation for developing new cassava cultivars that mature faster and are more resistant to diseases.

P3.27 DOGTAG: A NEW PROXIMITY LABELLING PROTEIN-PROTEIN INTERACTION METHOD DEVELOPED FOR USE IN PLANTS

Wednesday 5 July 2023 POSTER SESSION

Charlotte H Hurst (University of Dundee, United Kingdom), Sally M Myles (University of Dundee, United Kingdom), Sonica Chaudry (University of Dundee, United Kingdom), Jens Tilsner (University of St Andrews, United Kingdom), Paul RJ Birch (University of Dundee, United Kingdom), Piers A Hemsley (University of Dundee, United Kingdom)

c.h.z.hurst@dundee.ac.uk

Protein-protein interactions (PPIs) are a key component of cellular processes. Many different techniques for studying PPIs have been developed such as Co-Immunoprecipitations, Yeast-2-Hybrid and microscopy approaches. Newer PPI methods, such as BioID and APEX, involve proximity labelling using biotinylation to identify interacting proteins. However, there are drawbacks associated with all of these approaches. Here we present DogTag, a new proximity labelling technique optimised for use in plants to overcome many of these drawbacks.

DogTag uses a prokaryotic ubiquitin-like protein (Pup) that is post translationally added to proteins by a peptide ligase enzyme, PafA, in a process known as pupylation. This method can be used in a whole organism context, is genetically encoded so does not rely on the addition of exogenous substrates and can identify a breadth of PPIs including weak and transient interactions. DogTag is also suitable for detecting both membrane and cytosolic PPIs.

We present its use during plant-pathogen interactions for detecting membrane and cytosolic PPIs. DogTag can detect the translocation of cytosolic effectors from the oomycete pathogen that causes potato late blight,Phytophthora infestans,into plant hosts. It can also be used to detect proteins interacting with the membrane-bound Receptor Kinase FLS2, the receptor for bacterial flagellin.

P3.28 STRESS RESPONSE AND NUTRIENT HOMEOSTASIS: COORDINATION BY RICE CALCIUM-DEPENDENT PROTEIN KINASES

Wednesday 5 July 2023 POSTER SESSION

Isabel A. Abreu (ITQB NOVA, Portugal) abreu@itqb.unl.pt

Calcium-dependent protein kinases (CDPKs) localize in the very core of the plant signaling networks that coordinate growth and defense. Their unique ability to directly translate the universal language of changes in cellular Ca2+ concentrations into target phosphorylation, with the diversification of their gene family and ubiquitous expression throughout plant development, make this versatile signaling relay suitable for coupling multi-signal molecular and cellular events. In response to external signals, CDPKs phosphorylate downstream protein targets to regulate growth and stress responses according to the environmental and developmental circumstances. The latest advances in our understanding of the metabolic, transcriptional, and protein-protein interaction networks involving CDPKs suggest that they directly influence plant carbon/nitrogen (C/N) balance and phosphate homeostasis. For example, OsCPK17 is required for proper cold stress response in rice, likely affecting the activity of membrane channels and carbon/nitrogen metabolism1 While OsCPK13 regulates inorganic phosphate homeostasis and responses to salt stress. We suggest that CDPKs are key hubs in the plant signaling pathways that link the rapid stress-responsive cellular processes with the longer-term overall regulation of metabolism and growth2 . Coupled with possible coordination with the SnRK1–TOR growth axis, CDPK-modified plants would possess upgraded proteomic machinery to perceive stress quickly and to adjust cellular and metabolic activities to improve—or at least maintain—yield and productivity under stress.

References:

1. Almadanim, M. C.et al.Plant Cell Environ.40, 1197-1213 (2017).

2. Alves, H. L. S.et al.J. Exp. Bot.72, 4190–4201 (2021).

Jennifer Schoberer (University of Natural Resources and Life Sciences Vienna, Austria), Katharina Bauer (University of Natural Resources and Life Sciences Vienna, Austria), Mathias Ried (University of Natural Resources and Life Sciences Vienna, Austria), Richard Strasser (University of Natural Resources and Life Sciences Vienna, Austria)

jennifer.schoberer@boku.ac.at

The Arabidopsis protein MNS3 is an ER-α-mannosidase that is involved in the processing of asparagine (N)-linked oligosaccharides of proteins. Despite its presumed biosynthetic function in the endoplasmic reticulum (ER), MNS3 resides in the Golgi apparatus at steady-state. This is due to an amino acid signal motif (LPYS) within its cytoplasmic tail, which retains the enzyme in the Golgi. To identify proteins that potentially bind to this novel signal motif, we used different proteomics approaches in Arabidopsis thaliana and Nicotiana benthamiana that yielded a set of ER- and Golgi-located candidate proteins with known regulatory functions in cargo selection and transport. The most abundant candidates were cloned and examined for colocalisation with MNS3, and protein pull-down assays and FRET-FLIM were performed to confirm interactions. Interestingly, we identified a Rab-GTPase, which was able to modify MNS3 expression when both recombinant proteins were heterologously co-expressed in N. benthamiana. Our current work focuses on the characterisation of this novel Rab function.

P3.30 NONVESICULAR LIPID TRANSFER TO THE EXTRAHAUSTORIAL MEMBRANE DURING POWDERY MILDEW INFECTION IN BARLEY

Wednesday 5 July 2023

POSTER SESSION

Juan Martin D’Ambrosio (University of Copenhagen, Denmark), Hans Thordal‐ Christensen (University of Copenhagen, Denmark)

jmda@plen.ku.dk

Wednesday 5 July 2023

POSTER SESSION

The genesis and lipid-composition identity of membranes in different subcellular compartments is generated and balanced in part by nonvesicular lipid transfer. This fine-tuning process is carried out by specific lipid transfer proteins at the membrane contact site between two different subcellular membranes. Membrane contact sites are regions of close apposition between the two membranes of different organelles without fusion. The endoplasmic reticulum (ER) membrane, where lipid biosynthesis occurs, generates contact sites with most of the intracellular membranes, such as the plasma membrane, mitochondria, and lipid droplets. During powdery mildew infection to barley, in the cytosol of the epidermal cell that hosts the fungus, ade novomembrane is generated surrounding the haustoria, called the extrahaustorial membrane (EHM). However, little is known about its genesis, and vesicular trafficking does not seem to be involved in this process. Interestingly, the plant ER surrounds the extrahaustorial membrane, suggesting the formation of membrane contact sites and potential nonvesicular lipid transfer activity. OSBP-Related Proteins (ORPs) and synaptotagmins (SYTs) are two families of lipid transfer proteins identified in yeast, mammals, and plants and are localized in the MCS. Here, we show the induction of ORPs and SYTs in barley and evaluate its localization at the extrahaustorial membrane during powdery mildewBlumeria graminis f. sp. hordeiinfection. We evaluated the structure and role of the lipidbinding and transfer activity domains. Finally, we analyzedin vivothe lipid composition of EHM using phosphatidylinositol 4,5-bisphosphate and phosphatidylserine biosensors.

P3.29 MAPPING THE INTERACTOME OF THE GOLGI-RESIDENT ARABIDOPSIS N-GLYCAN-PROCESSING ENZYME MNS3

P4 - STOMATA - A MODEL SYSTEM FOR FUNDAMENTAL SCIENTIFIC DISCOVERY AND A TARGET FOR CROP IMPROVEMENT TO MEET DEVELOPMENT GOALS

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

P4.1 PHOTOSYNTHESIS – BEYOND THE LEAF

Wednesday 5 July 2023 POSTER SESSION

Alexandra L Milliken (University of Essex, United Kingdom), Philip Mullineaux (University of Essex, United Kingdom), Tracy Lawson (University of Essex, United Kingdom) am17191@essex.ac.uk

The majority of studies on photosynthesis and stomatal physiology focuses on leaves. However, research into nonfoliar photosynthesis is gaining interest with evidence that nonfoliar material including stems, fruits and ears/panicles/pods are able to photosynthesise at high rates and that carbon assimilation in these tissues maybe important for crop yield, particularly when leaves are stressed. Utilisation of a bespoke gas exchange chamber, chlorophyll fluorescence imaging and surface impressions across different types of nonfoliar organs allowed the characterisation of stomatal anatomy, gs , stomatal kinetics and photosynthesis within nonfoliar tissues. Nonfoliar organs showed the ability to respond to dynamically changing conditions, supporting the idea that stomata in nonfoliar material are functional, and most likely play an important role in gaseous exchange and uptake of atmospheric CO2 , as well as water loss and evaporative cooling, both of which impact photosynthetic carbon gain. Nonfoliar research remains a generally unexamined field of research for enhancing photosynthetic potential and plant water use efficiency under future climatic conditions.

P4.2 THE ROLE OF MITOCHONDRIAL H2S SOURCE (CAS-C1) IN PATHOGEN INDUCED STOMATAL CLOSURETHE LEAF

Wednesday 5 July 2023 POSTER SESSION

Carlos García-Mata (Mecanismos de Señalización en Plantas Instituto de Investigaciones Biológicas UNMDP, Argentina), Rosario Pantaleno (Mecanismos de Señalización en Plantas Instituto de Investigaciones Biológicas UNMDP, Argentina), Denise Scuffi (Mecanismos de Señalización en Plantas Instituto de Investigaciones Biológicas UNMDP, Argentina), Alex Costa (University of Milan Department of Biosciences Milan 20133, Italy)

camata@mdp.edu.ar

Stomata are microscopic structures in the epidermis of most land plants, formed by a central pore delimited by pairs of highly specialized cells, the guard cells. Stomatal poresmodulategas exchange between plants and the environment. Guard cells are able to senseexternal and internal stimuli and integrate them into a complex signalling network that triggers changes in the cellular volume to control pore size, leading to stomatal aperture or closure.

Stomatal pores are the natural entrance for microorganisms. As a consequence, plants evolved to recognize pathogen-associated molecular patterns (PAMPs), and trigger different signalling pathways in order to induce stomatal closure, as a first mechanical barrier to prevent infection.

The gasotransmitter hydrogen sulphide (H ₂ S), is a signal molecule involved in the modulation of different physiological processes including stomatal closure. Although H₂ S can be produced in different subcellular compartments, the role of mitochondrial H ₂ S in plants remains mostly unknown. In this work, we present data showing that mutants of the mitochondrial enzymatic source, β-cyanoalanine synthase (cas-c1) has an impairment on stomatal closure induction in response to the bacterial PAMP flagellin (flg22), to elf18, and to P.syringae. Moreover, we show that cas-c1guard cells have a cytosolic Redox imbalance at basal conditions, and an altered Redox response upon flg22 treatment. In summary, the results presented in the poster suggests that the mitochondrial H ₂ S source CAS-C1 is involved in the modulation of Redox homeostasis in pathogen-induced stomatal closure.

ORGANISED BY: ANDREW LEAKEY (UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN), TRACY LAWSON (UNIVERSITY OF ESSEX)

P4.3 GHR1 IN STOMATAL IMMUNITY RESPONSES OF ARABIDOPSIS THALIANA

Wednesday 5 July 2023

POSTER SESSION

Jasmin Kemppinen (University of Helsinki, Finland), Mikael Brosche (University of Helsinki, Finland), Maija Sierla (University of Helsinki, Finland)

jasmin.kemppinen@helsinki.fi

Stomata are critical sites for plant gas exchange and transpiration, but simultaneously provide entry-points for pathogens. Guard cells can detect pathogen-associated molecular patterns (PAMPs) and adjust stomatal aperture accordingly. Pathogen-triggered stomatal closure is amongst the fastest immunity responses, and requires a sophisticated network of molecular players, e.g., pattern recognition receptors, kinases, calcium ions and reactive oxygen species, which ultimately activate anion channels leading to stomatal closure.

The earliest event in stomatal immunity is the recognition of PAMPs by receptors, many of which belong to the large protein family of leucine-rich repeat receptor-like proteins (LRR-RLPs). Specific PAMPs are bound by the extracellular motifs of LRR-RLPs, followed by an interaction with a co-receptor and an activation of intracellular kinases and downstream signalling. Some co-receptors can interact with several different receptors, suggesting that protein-protein-interactions may operate dynamically.

One integral guard cell membrane LRR-RLP is GUARD CELL HYDROGEN PEROXIDE-RESISTANT 1 (GHR1), which can activate S-type anion channel SLAC1. In the model organism Arabidopsis thaliana, knockout mutants are unable to close their stomata in response to various abiotic signals such as CO2 and ozone, but are also insensitive to flg22, a flagellin epitope from Pseudomonas bacteria. This project aims to discover GHR1’s role in the earliest stomatal immunity events by reverse genetic and proteomic approaches. The main objectives are to characterize immunity responses and identify novel interactions in biotic stress. Future studies may uncover the dynamic nature of protein interactions in guard cells, highlighting plants’ ability to respond to a changing environment.

P4.4 MAKING BETTER PORES - HOW STOMATAL FORM IMPROVES STOMATAL FUNCTION IN GRASSES

Thursday 6 July 2023 09:00

Michael T Raissig (University of Bern, Switzerland), Tiago DG Nunes (Heidelberg University, Germany),

Lea S Berg (University of Bern, Switzerland),

Roxane P Spiegelhalder (University of Bern, Switzerland),

Dan Zhang (Heidelberg University, Germany),

Kim N Janssen (Heidelberg University, Germany),

Heike Lindner (University of Bern, Switzerland)

michael.raissig@unibe.ch

Stomata are microscopic “breathing pores” on land plants that balance photosynthetic carbon dioxide uptake with water vapour loss. Plant fossils suggest that the ancestral stomatal morphology consisted of two kidney-shaped guard cells (GCs) surrounding the central pore and most extant land plants still form kidney-shaped GCs. Grasses, however, form derived stomatal complexes consisting of two dumbbell-shaped GCs flanked by two lateral subsidiary cells (SCs). This “graminoid”

morphology is linked to faster stomatal kinetics and higher wateruse efficiency. We use the model grass Brachypodium distachyon to decipher (1) how SCs are recruited and formed, (2) how grass GCs morph into dumbbell-shaped cells (3) and how the innovative grass stomatal form affects function. We use developmental genetics and cell biological approaches to identify the developmental modules that affect the morphology and cellular composition of grass stomata. By mutating or overexpressing some of these factors we can manipulate grass stomatal morphology and assess how changing stomatal form affects gas exchange physiology within a single species. Finally, we started to use single-cell RNA sequencing to build a cell atlas of the developing grass leaf at single-cell resolution to identify novel genes involved in stomatal development and function. Together, we aim to comprehensively identify all relevant developmental modules and their cellular roles in the making of the most innovative stomatal morphology in the plant kingdom to understand how the graminoid form improves function.

P4.5 CELL WALL COMPOSITION AND GEOMETRY IN GRASS STOMATA

Thursday 6 July 2023 09:30

Shauni McGregor (University of Sheffield, United Kingdom), Andrew Fleming (University of Sheffield, United Kingdom), Julie Gray (University of Sheffield, United Kingdom)

s.mcgregor@sheffield.ac.uk

Plants control their rate of gas exchange and water loss to best suit the current environment by changing the size of their stomatal pores. To achieve this, guard cells change shape repeatedly, undergoing recurrent stress and strain, which is reflected in their specialised cell wall structure. Grass species, which provide over half of the world's food calories, have a distinct stomatal form that opens and closes faster than most plants. In this study, we investigate the guard cell wall composition and geometry of grasses to understand their role in this enhanced stomatal function. We use monoclonal antibodies to identify guard cell wall-specific polysaccharides and characterise the cell wall composition in grass leaves. Our results, combined with transmission electron microscopy and controlled enzyme digests, demonstrate that guard cell wall composition and geometry work synergistically to enable proper stomatal function in grasses. These findings shed light on the mechanism behind grass stomatal function and have important implications for understanding plant adaptation to changing environments.

Thursday 6 July 2023 09:45

Matthew J Wilson (University of Sheffield, United Kingdom), Clinton H Durney (John Innes Centre, United Kingdom), Shauni McGregor (University of Sheffield, United Kingdom), Jodie Armand (University of Sheffield, United Kingdom), Richard S Smith (John Innes Centre, United Kingdom), Julie E Gray (University of Sheffield, United Kingdom), Richard J Morris (John Innes Centre, United Kingdom), Andrew J Fleming (University of Sheffield, United Kingdom)

P4.6 GRASSES EXPLOIT GEOMETRY TO ACHIEVE IMPROVED GUARD CELL DYNAMICS

matthew.j.wilson@sheffield.ac.uk

Repeated, reversible adjustments of the stomatal pore to regulate plant gas exchange are driven by changes in guard cell (GC) turgor pressure. The 4-celled stomata of grasses have a distinctive geometry. Unlike stereotypical kidney-shaped GCs, grass GCs are dumbbellshaped and flanked by specialised lateral subsidiary cells (SCs). SCs are thought to enhance performance by acting as a local pool of ions and metabolites to drive the changes in GC turgor pressure which open/close the stomatal pore. To investigate the contribution of the specific cellular geometry of grass guard cells to improved stomatal performance, we created a 3D mechanical model of a grass stomatal complex that successfully recapitulates experimentally observed pore opening/closure. Both in silico exploration of the model and experimental mutant analysis supports the importance of a reciprocal pressure system between GCs and SCs for effective stomatal function. Our results demonstrate that lateral SCs are not essential for grass stomatal function, but when present result in a greater responsivity of pore aperture to change in GC turgor pressure. Additionally, we show that cellulose anisotropy in the GC wall is not required for grass stomatal function (in contrast to the consensus for kidney-shaped GCs), but that a relatively thick cell wall in the GC rod region is needed to enhance pore opening. Our model demonstrates the importance of the specific cellular geometry and associated mechanical properties in ensuring efficient grass stomatal function.

P4.7 CGMP SIGNALLING IN ARABIDOPSIS

Thursday 6 July 2023 10:00

Maeve C Dale (University of Bristol, United Kingdom), James W Clark (University of Bristol, United Kingdom), Deirdre H McLachlan (University of Bristol, United Kingdom), Glyndwr S Jones (University of Bristol, United Kingdom), Alistair M Hetherington (University of Bristol, United Kingdom)

in19233@bristol.ac.uk

cGMP is a cyclic nucleotide which is involved in the response to external stimuli. Although cGMP is well established as an intracellular second messenger in animals the role it plays in plant cell signalling remains to be fully described. Recently we characterised the Arabidopsis PDE1 gene that encodes a cyclic nucleotide phosphodiesterase involved in cGMP breakdown. We used this to investigate the role of cGMP in plants. cGMP was found to be involved in glutamate-induced stomatal closure, and RNA sequencing was carried out to investigate this further. Our results demonstrate cGMP is involved in glutamate signalling as mutants in the cGMP pathway showed alterations in both their stomatal response and differential gene expression. RNA sequencing also allowed us to identify patterns in differential gene expression and highlight areas of interest for further study. Our findings show a link between PDE1 and stress responses, indicating that cGMP may be involved in these responses.

P4.8 STOMATAL DYNAMICS AND HYDRAULIC TRAITS DEPEND ON ANATOMICAL FEATURES AND PHOTOSYNTHETIC PATHWAY

Thursday 6 July 2023 11:00

Yanmin Zhou (University of Sheffield, United Kingdom), Colin Osborne (University of Sheffield, United Kingdom)

yzhou182@sheffield.ac.uk

Anatomical structure and photosynthetic pathway influence stomatal dynamics and water relations, and further impact the balance between carbon fixation and water loss in plants. However, little is known about how the evolution of C4 photosynthesis interacts with anatomical structure and environmental factors to change stomatal dynamics and hydraulic traits. In this study, Alloteropsis semialata was used as a model system to show that C4 individuals had a slower stomatal opening speed than non-C4 species for a given guard cell length. Among C4 diploids, stomatal opening was faster when plants migrated into wetter habitats. However, polyploid formation in some C4 lineages resulted in larger guard cells, which further slowed stomatal opening. In addition, the enlargement of bundle sheath tissue in C4 compared with non-C4 plants was associated with greater leaf capacitance. There was a positive relationship between minor vein density and leaf hydraulic conductance across both C3 and C4 lineages, with the high vein density of Kranz anatomy linked to greater conductance. However, these traits only showed a weak relationship among C4 plants. These results indicate that the evolution of C4 photosynthesis in A. semialata was initially accompanied by a slowing of stomatal opening speed, implying a perturbation of stomatal biochemistry. The anatomical changes accompanying the transition to C4 photosynthesis were also associated with higher leaf capacitance and greater hydraulic conductance, but a less negative turgor loss point. However, subsequent diversification of opening speed and hydraulic traits have been caused by secondary adaptations to climate and polyploid formation.

P4.9 MANIPULATING STOMATAL LIGHT RESPONSE TO IMPROVE PHOTOSYNTHESIS AND WUE

Thursday 6 July 2023 11:00

Tracy Lawson (University of Essex, United Kingdom), Silvere Vialet Chabrand (Wageningen University, Netherlands), Jack S. A Matthews (University of Essex, United Kingdom), Cristobal Uauy (JIC, United Kingdom), James Simmonds (JIC, United Kingdom), Alexandra L Milliken (University of Essex, United Kingdom), Menjie Fan (University of Essex, United Kingdom)

tlawson@essex.ac.uk

In order for leaf photosynthesis to take place CO2 must enter the leaf through adjustable pores, called stomata, and at the same time water is lost through these pores which also aids in cooling of the leaf. Stomata open in response to increasing light, however this response depends on the wavelength of light, and two responses have been identified. The first named the “red” light or mesophyll response, occurs at high light levels and is linked directly to the rate of photosynthesis. The second is the “specific blue” light response, which occurs and is saturated at light

levels too low to drive photosynthesis. This means that stomata are often more open than they need to be to achieve maximum CO2 uptake for photosynthesis, and therefore the ratio of carbon gain to water loss known as Water Use Efficiency (WUE) is reduced. Here we examine stomatal sensitivity to blue light in a number of species and explore the potential to manipulate this process to optimise crop resource use. A second strategy we are exploring is the speed of stomatal responses to changes in light intensity. As stomatal responses tend to be an order of magnitude greater than photosynthetic responses this can lead to periods of reduced assimilation when stomatal opening is slow as well as periods of unnecessary water loss by slow stomatal closure when the photosynthetic rate has dropped. Both of these approaches have the potential to increase crop photosynthesis and WUE, which are critical for yield.

P4.10 STOMATA: SUNLIGHT AND SHADE

Thursday 6 July 2023 11:30

Ashley J Pridgeon (University of Bristol, United Kingdom), Mathilda Gustavsson (University of Bristol, United Kingdom), Keara A Franklin (University of Bristol, United Kingdom)

ashley.pridgeon@bristol.ac.uk

Water availability and light quantity/quality are among the key factors that determine the likelihood of seedling survival. Stomata are microscopic valve-like structures on plant epidermises that control the uptake of CO2 and the loss of H2 O. Plants regulate gas exchange through stomata on both short-term scales (through rapid movement, ie. the opening and closing of the pore) and long-term scales (through changes in cell size and stomatal density). Even though we know a great deal about the contribution of stomata to the ability to withstand stress in mature plants, their role in seedling establishment is much less clear.

In this study we investigate how exposure to different light qualities affect the regulation of stomatal movements in Arabidopsis thaliana seedlings. These light qualities include white light (light wavelengths between 400-700nm) supplemented with low dose ultraviolet B (UV-B – between 280-315nm), and white light supplemented with far red light (FR – between 725-735nm). These light conditions were chosen to simulate aspects of direct sunlight (which contains light within the UV part of the spectrum) and surrounding vegetation (which selectively transmits and reflects FR light) respectively. We find that both signals have effects on stomatal movements, and we investigate the underlying mechanisms mediating these stomatal responses.

P4.11 INVESTIGATING STOMATAL RESPONSES TO RED LIGHT

Thursday 6 July 2023 11:45

Georgia E Taylor (University of Cambridge, United Kingdom), Dr Julia Walter (University of Cambridge, United Kingdom), Dr Johannes Kromdijk (University of Cambridge, United Kingdom)

get27@cam.ac.uk

Stomata are microscopic pores on the leaf epidermis which coordinate gas exchange. Stomatal opening is regulated in response to environmental conditions, balancing carbon gain with water loss. The stomatal response to red-light, also known as the quantitative

light response, appears to provide a link between photosynthesis and stomatal opening. However, the mechanisms by which this response is regulated have been debated. Initially, work suggested that changes in intercellular CO2 (Ci) provided the main cue, indirectly coupling the mesophyll’s demand for carbon with stomatal opening, via a Ci-dependent response. However, evidence for Ci-independent mechanisms suggests an additional, more direct relationship with photosynthesis itself. This study aimed to disentangle these two proposed mechanisms of stomatal control. By controlling Ci at fixed values across a range of light intensities, we obtained a matrix of responses to both CO2 and red-light that allowed us to understand the individual contribution of these cues to stomatal opening. Here, we demonstrate that both Ci-dependent and -independent mechanisms function in red-light stomatal opening. However, at high Ci concentrations, red-light induced stomatal opening is suppressed by the response to high CO2 . Unexpectedly, we also observed that the Ci-dependent response occurs independently of light. Overall, these results provide further insight into the mechanisms which control stomatal movements in response to red light and highlight the need for future work to fully elucidate the molecular regulation involved.

P4.12 ROOT-SOURCED ABA EFFECTS ON TOMATO STOMATAL RESPONSES VARY WITH EVAPORATIVE DEMAND AND SCION ABA STATUS

Thursday 6 July 2023 12:00

Ian C Dodd (Lancaster University, United Kingdom), Vasileios Giannakopoulos (Lancaster University, United Kingdom)

I.Dodd@lancaster.ac.uk

High atmospheric vapour pressure deficit (VPD) increases transpiration, perturbing leaf water status unless partial stomatal closure occurs. Shoot ABA biosynthesis causes stomatal closure at high VPD, but rootstock can affect stomatal responses and shoot ABA accumulation when wild-type (WT) and ABA-deficient mutants are reciprocally grafted. To evaluate whether root-sourced ABA regulates stomatal responses to VPD, WT and ABA-deficientflaccatomato plants were self- and reciprocally-grafted, grown at low (0.2 kPa) VPD, then exposed to high (1.2 kPa) VPD for 1 hour in a whole plant gas exchange chamber. Measurements comprised transpiration and foliar ABA concentrations (both VPDs) and leaf water potential (high VPD). In graft combinations selected for comparable leaf area, transpiration of selfgraftedflaccaplants at low VPD was 4-fold higher than all other graft combinations, in which transpiration rate was similar despite > 6-fold variation in foliar ABA concentration. At high VPD, transpiration of WT/ flacca(scion/rootstock) plants was twice that of WT/WT plants (while foliar ABA concentration was halved), with allflaccascions (independent of rootstock) showing intermediate transpiration and low foliar ABA concentration. Leaf water potential was 0.16 MPa lower inflaccascions than WT scions, and rootstock independent. High VPD increased foliar ABA concentrations of all graft combinations similarly (suggesting shoot ABA biosynthesis), but rootstock effects on transpiration depended on VPD: WT rootstocks suppressed transpiration offlaccascions at low VPD whileflaccarootstocks enhanced transpiration of WT scions at high VPD. Thus root-sourced ABA mediated transpiration set-points, if not foliar ABA accumulation at high VPD.

P4.13 UNLEASHING THE POWER OF LIGHT: APPROACHES FOR ENHANCING PHOTOSYNTHESIS AND IMPROVING CROP YIELDS

Thursday 6 July 2023 12:15

Mengjie Fan (University of Essex NIAB, United Kingdom), Tracy Lawson (University of Essex, United Kingdom)

mf21430@essex.ac.uk

Plant phenotypic adaptation to changing growing conditions is a critical aspect of their evolution. Recent advances in low-cost lighting technology have enabled precise control over light conditions, facilitating the induction of desirable phenotypes and higher potential yields. Our experiments demonstrate that acclimation to specific spectral bands significantly enhances leaf photosynthetic capacity under both steady-state and dynamic light conditions by modifying leaf biochemistry and anatomical traits, thereby promoting gas exchange between the atmosphere and leaf inner cells. Moreover, our investigations highlight the existence of spectral variations across different species in response to dynamic spectra-dependent light exposure. To deepen our understanding of the light-mediated pathways involved in photosynthesis, we have engineered multiple transgenic plants exhibiting varying sensitivity to specific wavelengths of light radiation across different leaf cells. The ongoing aim of this project is to investigate the downstream effects of light-mediated pathways in plant cells and identify novel approaches for improving photosynthesis efficiency. Our study provides critical insights into the potential of manipulating light conditions to enhance crop productivity and advance sustainable agriculture.

P4.32 THE EVOLUTIONARY ORIGINS OF STOMATAL GUARD CELLS SIGNALLING

Thursday 6 July 2023 15:00

Natalia Hurtado Castano (University of Sheffield, United Kingdom), James Clark (University of Bristol, United Kingdom), Stuart Casson (University of Sheffield, United Kingdom), Julie Gray (University of Sheffield, United Kingdom), Alistair Hetherington (University of Bristol, United Kingdom)

n.hurtado@sheffield.ac.uk

The acquisition of stomata is one of the main adaptations of plants colonisation to terrestrial environments. Stomata are small pores found in the epidermis of the leaves, responsible for gas exchange and surrounded by two guard cells, which control the aperture and closure by the response to diverse stimuli, either internal or external, which include circadian clock, light, CO2 concentration, humidity and temperature. Based on the incomplete knowledge about the evolutionary origins of stomata and the guard cell signalling regulatory pathways, this project aims to identify the key genetic innovations that underpin stomatal evolution, reconstruct the gene content of the ancestral guard cell and analyse the role of the identified genes in stomatal function using a combination of genetic, phylogenomics and physiological analysis.

Whole leaf and guard cell-enriched epidermis transcriptomes were generated from a range of plant species across the embryophyte lineage, leading to the initial identification of genes differentially expressed in guard cell-enriched epidermis and the selection of a subset with a reported role in abiotic responses that might enhance osmotolerance upon overexpression or silencing, but with an unknown function on stomatal regulation.

P4.14 MANIPULATING

CROP STOMATAL DENSITY FOR IMPROVED WATER-USE EFFICIENCY AND CLIMATE RESILIENCE

Thursday 6 July 2023 14:30

Jessica Dunn (University of Sheffield, United Kingdom), Julie Gray (University of Sheffield, United Kingdom) jessica.dunn@sheffield.ac.uk

Stomata control the uptake of CO2 for photosynthesis, and the loss of water via transpiration. As such, stomata influence plant water-use efficiency (WUE) and transpirational cooling. These traits are vitally important in a changing climate in which water limitation and elevated temperatures are becoming more frequent and severe.

Several EPIDERMAL PATTERNING FACTOR (EPF) genes encode peptide signals that can promote or inhibit stomatal development. By overexpressing EPFs we have produced substantial reductions in stomatal density in several globally important crop species, and have demonstrated promising improvements in WUE and drought tolerance. Here, I present work in which I have explored the effects of manipulating EPF levels on different organs in wheat. I discuss the effects that these manipulations had on leaf development and physiology, and demonstrate that in addition to altering leaf stomatal density, EPF manipulations can also substantially alter stomatal development on nonfoliar organs.

Thermal imaging screening was performed on Arabidopsis lines with a T-DNA insertion on the genes of interest. T-DNA lines and wild type plants were exposed to increases on CO2 concentration (480 ppm to 1000 ppm). T-DNA lines with significant differences on leaf temperature under [CO2 ] compared to WT were further analysed in order to determine if both stomatal anatomy and conductance are responsible of this response.

P4.34 MANIPULATING STOMATAL DENSITY AND FUNCTION TO ENHANCE CARBON ASSIMILATION IN STRAWBERRY

Thursday 6 July 2023 15:15

William DB Atkinson (University of Essex, United Kingdom), Prof. Tracy Lawson (University of Essex, United Kingdom), Dr. Andrew J Simkin (University of Kent, United Kingdom)

willatkinson_97@hotmail.co.uk

Increasing global food production is necessary to meet the nutritional demands of the growing population. Enhancing the carbon assimilation of the cultivated strawberry, Fragaria x annanassa, could improve the yield and quality of the fruit to address this problem. To achieve this, we aim to improve the stomatal density and function to enhance carbon assimilation and reduce unnecessary water loss in Strawberry. Increasing stomatal density can be attained through the overexpression of the epidermal patterning factor gene STOMAGEN, which was shown to increase carbon assimilation by 30% at the cost of increased

transpiration. Increasing stomatal density can also be achieved through the targeted knockout of epidermal patterning factor genes that act as antagonists to STOMAGEN. Improving stomatal function can be achieved by increasing the speed of stomatal opening and closure to allow them to better respond to environmental signals. Guard cellspecific overexpression of the sugar-sensing enzymes can increase stomatal closure speed during periods of high photosynthesis when offloading photosynthetic products is now the limiting factor, which decreases transpiration and improves intrinsic water use efficiency. We aim to produce a range of strawberry plants with increased stomatal density, through both the overexpression of STOMAGEN and CRISPR/Cas9 mediated knockouts of STOMAGEN antagonists, increased rates of stomatal opening and closure, through the guard cell-specific expression of sugar sensing enzymes. These genes will be expressed individually and in combination to assess potential additive effects on fruit yield and quality.

P4.18 MCOMPENSATORY MECHANISMS OF STOMATAL OPENING DAMPEN EFFORTS TO IMPROVE WATER USE EFFICIENCY BY ENGINEERING PLANTS WITH LOWER STOMATAL DENS

Thursday 6 July 2023 15:45

Daniel Tejeda-Lunn (University of Illinois Urbana-Champaign, United States), Kannan Kaskaran (University of Florida, United States), Alayna Trejo (University of Illinois UrbanaChampaign, United States), Fredy Altpeter (University of Florida, United States), Andrew D. B. Leakey (University of Illinois Urbana-Champaign, United States)

dtl@illinois.edu

Stomatal pores regulate the exchange of CO2 and water vapor between leaves and the atmosphere. Engineering plants with lower stomatal density by over-expressing epidermal patterning factors can reduce transpiration and increase plant water use efficiency. However, the quantitative relationship between reductions in stomatal density and stomatal conductance is still poorly resolved. We aimed to address this knowledge gap while testing the anatomical and physiological plasticity of sugarcane over-expressing EPIDERMAL PATTERNING FACTOR 2 (OE-EPF2) from Sorghum bicolor. Stomatal conductance of EPF2-OE was equivalent to wild-type, despite significantly reduced stomatal density on both abaxial (-27%) and adaxial (-16%) leaf surfaces associated with reduced stomata number per file of cells. A meta-analysis of seven C3 and four C4 species revealed a correlation between engineered reductions in stomatal density and lower stomatal conductance. In C4 species, the reduction in stomatal conductance is consistently dampened relative to the reduction in stomatal density. In some C3 species, modest reductions in stomatal density are more directly proportional to reductions in stomatal conductance. In EPF2OE sugarcane, neither stomatal-complex length, stomatal-complex width, specific leaf area, leaf nitrogen content, nor chlorophyll differed from wild-type. The absence of changes in stomatal-complex size or proxies of photosynthetic capacity suggests that greater capacity for stomatal opening likely dampens the effects of reduced stomatal density on stomatal conductance. In the future, we hope to test this hypothesis by developing the capability to assess pore size by microscopy while simultaneously controlling environmental conditions and measuring gas exchange.

P4.19 A HARD DAY’S NIGHT; DETERMINING A ROLE FOR STOMATAL CONDUCTANCE IN NOCTURNAL HEAT TOLERANCE

Thursday 6 July 2023 16:30

Lorna McAusland (University of Nottingham, United Kingdom), Liana G Acevedo-Siaca (Associate Lead Author) (Michigan State University, United States), Suzuky Pinto (Instituto Tecnológico de Sonora (ITSON), Mexico), Francisco Pinto (International Maize and Wheat Improvement Centre (CIMMYT), Mexico), Gemma Molero (KWS Momont Recherche, France), Jaime Garatuza-Payan (Instituto Tecnológico de Sonora (ITSON), Mexico), Matthew Reynolds (International Maize and Wheat Improvement Centre (CIMMYT), Mexico), Erik H Murchie (University of Nottingham, United Kingdom), Enrico A Yepez (Instituto Tecnológico de Sonora (ITSON), Mexico)

lorna.mcausland@nottingham.ac.uk

Nocturnal temperatures are rising at 1.4x the rate of daytime temperatures. In North-western Mexico, every 1 o C increase in nighttime temperatures is associated with a 6-10% decline in spring wheat yields. Under growing climactic uncertainty, it is vital to identify and understand physiological mechanisms which enable nocturnal heat tolerance. Nocturnal stomatal conductance (gsn) represents a significant, enigmatic source of night-time water-loss in wheat, with implications for whole plant metabolism, thermal regulation and water-use efficiency.

Here we present the results of 3 years of field data subjecting 12 spring T. aestivum genotypes grown in NW Mexico to an artificial increase in night-time temperatures of 2 o C. Under nocturnal heating, grain yields decreased (1.9% per 1°C) without significant changes in daytime leaf-level responses, such as daytime stomatal conductance (gs). Under warmer nights, there were significant differences in the magnitude and decrease in gsn , values of which were between 9-33% of daytime gs . The decrease in grain yield was genotype-specific; genotypes categorised as heat tolerant, with low gsn , demonstrated some of the greatest declines in yield in response to increased nocturnal temperatures. We conclude the essential components of nocturnal heat tolerance in wheat are uncoupled from resilience to daytime temperatures, raising fundamental questions for physiological breeding.

P4.20 NOVEL REGULATORS OF GUARD CELL SIGNALLING

Thursday 6 July 2023 17:00

Roosa Haajanen (University of Helsinki, Finland), Dmitry Yarmolinsky (University of Tartu, Estonia), Triin Vahisalu (University of Helsinki, Finland), Hannes Kollist (University of Tartu, Estonia), Cezary Waszczak (University of Helsinki, Finland), Maija Sierla (University of Helsinki, Finland), Jaakko Kangasjärvi (University of Helsinki, Finland)

roosa.haajanen@helsinki.fi

Stomata are microscopic pores on the leaf epidermis that consist of two specialised cells called guard cells, which regulate the intake of carbon dioxide and the transpiration of water from the plant. The

stomatal aperture is controlled by changes in cell turgor pressure caused by the movement of osmoregulatory ions and water in response to various endogenous and environmental stimuli, such as high internal carbon dioxide concentration and ozone. Ozone is one of the major air pollutants, and upon entering leaf tissues through stomata, it is converted to reactive oxygen species (ROS) in the apoplast. ROS burst represents one of the earliest responses to abiotic stresses, leading to signalling cascades that initiate stomatal closure. Plants with more open stomata or stomatal closure dysfunction are known to develop lesions when exposed to ozone, thus making ozone an excellent tool to screen for stomatal mutants. Using this strategy, we conducted a forward genetics screen to identify novel regulators of stomatal function. The screen yielded approximately 76 novel mutants impaired in stomatal closure, of which 48 were impaired in high CO2-induced responses. By mapping newly identified mutants, combined with interactomics approaches targeting well-established regulators of guard cell signalling, we aim to saturate the CO2 guard cell signalling network.

P4.21 IDENTIFYING

Thursday 6 July 2023 17:15

Vasileios Giannakopoulos (Lancaster University, United Kingdom), Dr Milan Urban (International Center for Tropical Agriculture (CIAT CGIAR), Colombia), Prof Ian Dodd (Lancaster University, United Kingdom)

v.giannakopoulos@lancaster.ac.uk

Vapour pressure deficit (VPD) is one of the most important factors regulating stomatal behaviour. Transpiration increases linearly with VPD, although some genotypes initiate stomatal closure beyond a VPD threshold, to restrict transpiration rate and maintain leaf water status. Few studies have investigated the mechanisms of VPD-induced stomatal closure in common bean (Phaseolus vulgaris). Utilising a novel whole-plant gas exchange chamber that could rapidly impose changes in VPD around the plant, five bean genotypes with variation in temperature tolerance were screened at different developmental stages to identify genotypic variation in stomatal responses to elevated VPD and to determine underlying physiological mechanisms. Three genotypes (SMR107, SEN97, SMR101) limited their transpiration rate (TR) at high VPD with a break-point (BP) range of 1.8<BP<2.5 kPa and two genotypes (Calima, HTA4) had a linear TR response to VPD. Despite this variability in stomatal response to VPD, high VPD caused a similar decline in leaf water potential in all genotypes. High VPD significantly increased foliar abscicic acid and jasmonic acid concentrations, suggesting these hormones may regulate stomatal responses of bean to evaporative demand. However, whether root or shoot hormone synthesis modulates stomatal closure in response to elevated VPDs should be addressed.

P4.22 DOES CARBON DIOXIDE ACT THROUGH GIBBERELLINS TO ALTER GUARD CELL SENSITIVITY TO ABSCISIC ACID?

Thursday 6 July 2023 17:30

Stuart Casson (University of Sheffield, United Kingdom), Kishwar J Shethi (University of Sheffield, United Kingdom), Natalia Hurtado-Castano (University of Sheffield, United Kingdom), Julie E Gray (University of Sheffield, United Kingdom)

s.casson@sheffield.ac.uk

Carbon dioxide (CO2 ) and abscisic acid (ABA) are key regulators of stomatal aperture, with both known to promote stomatal closure. CO2 and ABA signalling pathways converge to regulate stomatal closure and furthermore, it has been proposed that CO2 primes stomatal sensitivity to ABA by regulating the expression of ABA receptors. However, it is a common feature of signalling pathways for an antagonist to regulate the sensitivity of a system to a particular signal. Gibberellins (GA) are well known antagonists of ABA signalling and here we address whether GAs can antagonise guard cell responses to ABA and if elevated CO2 (eCO2 ) acts on GA signalling or biosynthesis to promote stomatal closure. Using epidermal strip bioassays and leaf gas exchange measurements alongside treatments with GA or GA biosynthesis inhibitors, we demonstrate that GA does antagonise ABA and eCO2 promotion of stomatal closure. eCO2 responses are also affected in mutants in GA signalling and biosynthesis and mass spectrometry measurements show that eCO2 treatments do alter leaf GA content. Together, this suggests that eCO2 could alter guard cell sensitivity to ABA by targeting its antagonist, GA.

P4.23 EPIDERMAL ANTHOCYANINS AS MODULATORS OF STOMATAL FUNCTION IN ARABIDOPSIS

Thursday 6 July 2023 17:45

Tiago D G Nunes (University of Helsinki, Finland), Jasmin

A Kemppinen (University of Helsinki, Finland), Juha-Pekka Hieta (University of Helsinki, Finland), Nina Sipari (University of Helsinki, Finland), Xavier Zarza (University of Helsinki, Finland), Teemu Teeri (University of Helsinki, Finland), Maija Sierla (University of Helsinki, Finland)

tiago.gomes@helsinki.fi

Stomata are cellular pores formed by two guard cells (GCs) on the leaf epidermis that can open and close according to the environment to optimise carbon assimilation and save water. Stomatal movements are achieved by changes in osmotic and turgor pressure in the GCs. The responsiveness of stomatal movements is crucial for plants’ plasticity and resilience to abiotic and biotic stresses. While GC signalling is well known, the molecular interaction and coordination with the neighbouring tissues for regulating stomatal function remains mostly unexplored. We have observed the accumulation of anthocyanins in the epidermal cells adjacent to the GCs in Arabidopsis in response to abiotic stress and have preliminary evidence for its relevance in stomatal function. We will decode the metabolome of the leaf epidermis in response to abiotic stress and characterise the impact

GENOTYPIC VARIATION AND PHYSIOLOGICAL MECHANISMS OF COMMON BEAN (PHASEOLUS VULGARIS) STOMATAL RESPONSE TO ELEVATED EVAPORATIVE DEMAND.

of anthocyanin production on stomatal function. We will investigate the metabolic profile of GCs and the adjacent epidermal cells using single-cell mass-spectrometry imaging and identify the metabolic signatures associated with anthocyanin accumulation using UPLC-MS. Next, the analysis of anthocyanin biosynthesis mutants will help us to understand how stomatal function and gas exchange are modulated by anthocyanin accumulation. Understanding how stomata and the surrounding tissue are coordinated and identifying targets to improve stomatal responsiveness may provide tools for improving water-use efficiency and breeding plants with enhanced climate resilience.

P4.24 PHENOMICS OF STOMATA AND WATER USE EFFICIENCY IN C4 CROPS

Friday 7 July 2023 09:00

Andrew D.B. Leakey (University of Illinois at UrbanaChampaign, United States)

leakey@illinois.edu

Water use efficiency (WUE), which is physiologically distinct from drought tolerance, is a key target for improving crop productivity, resilience and sustainability. This is because water availability is the primary limitation to crop yield globally and irrigation uses the largest fraction of our limited freshwater supply. The exchange of water and CO2 between a leaf and the atmosphere is regulated by the aperture and pattern of stomata. Mechanistic modeling indicates that stomatal conductance could be reduced or stomatal movements accelerated to improve water use efficiency in important C4 crops such maize and sorghum. While molecular genetics has revealed much about the genes regulating stomatal patterning and kinetics in Arabidopsis, knowledge of the genetic and physiological control of WUE by stomatal traits in C4 crops is still poor. Understanding of natural diversity in stomatal traits has limited by the lack of high-throughput phenotyping (HTP) methods. Here we report the development and methods for phenotyping stomatal patterning, stomatal speed, and stomatal aperture, as well as the application of machine learning and other analytical approaches that can be exploited to leverage the resulting data to address long-standing questions about the genetics and physiology of stomatal form and function. In addition, we report the results of experiments taking a transgenic approach to engineering greater WUE in model C4 species.

P4.25

PHOTOSYNTHESIS

j.mathan@essex.ac.uk

The potential of natural genetic variation to improve photosynthesis in crop plants is immense, but largely unexplored. Identifying the underlying mechanism of variation could provide a potential novel strategy to improve photosynthetic performance and enhance crop productivity. Here, we used a tomato backcross inbred lines (BILs) population derived from a wild accession crossed with a domesticated cultivar to explore anatomical, physiological and biochemical variation in photosynthesis and associated processes. These traits were used to determine the potential QTLs responsible for the underlying variance in photosynthetic capacity/performance. In the current study, highthroughput phenotyping tools including infra-red gas exchange, hyperspectral reflectance, and chlorophyll fluorescence were used in both glasshouse and field-grown plants. Significant variation in photosynthetic capacity, SLA and sugar content were observed across the population, with the two parents illustrating the extremes of the phenotypic variation. Our analysis reveals the majority of the variation in photosynthesis could be explained by components related to maximum photosynthesis capacity. A negative relationship between Amax, Vcmax, and Jmax with SLA suggested that thicker leaves significant influence on the overall rate of photosynthesis. Light response analysis revealed that guard cell anatomy has a strong impact on stomata kinetics, suggesting manipulation of stomata features could be a potential strategy for controlling CO2 assimilation and water loss in tomatoes. Our study demonstrates the potential to utilise natural variation in existing tomato BIL population to improve photosynthesis and crop performance.

P4.26 HOW DO GUARD CELLS INTEGRATE LOCALLY PERCEIVED ENVIRONMENTAL STIMULI WITH SIGNALS RECEIVED FROM THE REST OF THE LEAF?

Friday 7 July 2023 09:45

Deirdre McLachlan (University of Bristol, United Kingdom), Tracy Lawson (University of Essex, United Kingdom), Colin Brownlee (Marine Biological Association, United Kingdom), Alistair Hetherington (University of Bristol, United Kingdom)

bzdml@bristol.ac.uk

Friday 7 July 2023 09:30

Jyotirmaya Mathan (University of essex, United Kingdom), John Ferguson (University of essex, United Kingdom), Matteo Dell’Acqua (Scuola Superiore Sant’Anna, Italy), Dani Zamir (Hebrew University, Israel), Jeremy Harbinson (Wageningen University, Netherlands), Johannes Kromdijk (University of Cambridge, United Kingdom), Tracy Lawson (University of essex, United Kingdom)

Stomata are subject to a range of endogenous and exogenous signals and stimuli that alter their pore apertures. Observations of large variations in apertures across a leaf have led to hypotheses of differing sensitivity in subpopulations of stomata, or of remote influence (signals from other cell types or other parts of the plant). Until recently, it has been difficult to monitor stomatal responses while maintaining spatial information, such as distance from vasculature and proximity and behaviour of neighbouring stomates. With the advent of mesolens microscopy, we can now monitor stomatal behaviour over a large area on an intact leaf, whilst applying stimuli to discrete regions. This groundbreaking technology allows simultaneous imaging of thousands of cells at single cell resolution. Furthermore, with timelapse imaging, we can determine how each of these cells responds to any given stimulus. We examined stomatal responses to local and distal changes in light stimuli, enabling examination of stomatal behaviour to consistent versus conflicting exogenous and endogenous signals. Not only did we gain insights into how signals spread across the leaf, but we were also able to identify specific signalling components involved in long distance signal propagation. Interestingly, this signal

EXPLORE THE

VARIATION AND LIMITATIONS IN RESPONSE TO STEADY STATE AND FLUCTUATING LIGHT IN TOMATO BILS POPULATION

has directionality, but does not appear to require the mid-vein for propagation.

P4.27 LEAF WIDTH: A TRAIT THAT REGULATES BOTH WATER-USE EFFICIENCY AND TOLERANCE TO HIGH TEMPERATURES IN C4 GRASSES

Friday 7 July 2023 10:00

Francisco Javier Cano (INIA-CSIC, Spain), Yazen Al-Salman (Wageningen University Research, Netherlands), Alexander Watson-Lazowski (Harper Adams University, United Kingdom), Charles Warren R Warren (The University of Sydney, Australia), Oula Ghannoum (Western Sydney University, Australia)

fjcanomartin@gmail.com

Crop productivity is treated by the high temperatures and dry conditions consequence of climate change. Albeit this situation is global, the percentage of population in tropical regions is increasing as well as the demand of food. In these regions C4 crops present great advantages over C3 cereals, however, the search for traits that promote adaptability to withstand water and heat stresses is increasingly valuable. Leaf transpiration is often considered a costly return to boost photosynthesis, although in turn it regulates leaf temperature. Hence a clear target for plant breeding in arid environments is to increase the water use efficiency without penalties for photosynthesis and especially at high temperatures. Here we present the theory behind the coupling of photosynthesis and transpiration in C4 grasses and how recently discovered relationships among leaf morphology, anatomy and physiology control the trade-off between productivity and efficiency. Furthermore, we demonstrate in sorghum the importance of leaf width for regulating both stomatal conductance, water use efficiency and associated anatomical traits and how leaf to air temperature difference is linked to leaf width. With all this evidence we aim to investigate the leaf width as a surrogate of breeding more efficient and more heat tolerant crops needed for current and future climate conditions.

P4.28 THE ROLE OF PHYTOCHROME PHOTORECEPTORS IN REGULATING PLANT RESPONSES TO TEMPERATURE

Friday 7 July 2023

10:15

Julian E Adams (University of Sheffield, United Kingdom), Julie E Grey (University of Sheffield, United Kingdom), Stuart Casson (University of Sheffield, United Kingdom)

jadams7@sheffield.ac.uk

Higher temperatures due to climate change are leading to large yield losses and are predicted to get worse in future. Night-time temperatures are increasing at a faster rate than the corresponding day-time temperatures over the last few decades. To study the effect of these temperatures on stomatal development and water use, the model organism Arabidopsis thalianais used. Phytochromes are photoreceptors present in the cytosol that upon absorption of red-light will change conformation from their inactive (Pr) form to the active (Pfr) form, allowing them to enter the nucleus and regulate several

pathways. Far-red light or darkness inactivates phytochromes back to the Pr state and this process is accelerated at higher temperatures, in a process called thermal reversion (Rockwell et al., 2006; Legris et al., 2016). Phytochrome B regulates stomatal development in response to higher irradiances of light, with phyB mutant plants having a reduced number of stomata (Boccalandro et al., 2009; Kang et al., 2009; Casson et al., 2009). Here, we investigate the impact of higher night-time temperatures upon Pfr abundance and stomatal development, as well as the physiological impacts on plant water use.

P4.29 SCALING LEAF WATER USE EFFICIENCY TRAITS TO THE CROP LEVEL FOR SUPPORTING CROP IMPROVEMENT

Friday 7 July 2023 11:00

Alex Wu (University of Queensland, Australia), Graeme Hammer (University of Queensland, Australia)

c.wu1@uq.edu.au

The amount of carbon gain relative to water use is a key target for crop improvement as water availability is the most important environmental factor limiting crop production. Leaf gas exchange traits such as photosynthetic CO2 assimilation rate and conductance to water vapour are fundamental traits underpinning crop growth–water relations and are targets for manipulation. But a deeper understanding of consequential whole-crop responses will be required. Here, I present a cross-scale model and predictions of likely consequences of manipulating sorghum leaf photosynthetic rate and conductance on canopy photosynthesis and transpiration, seasonal crop biomass and yield growth dynamics in contrasting water environments. Results highlight that complex, time series plant-by-environment interactions can confound sub-organ scale research efforts, but also identify photosynthesis and conductance combinations likely to generate best pay-off at the crop scale. Cross-scale modelling probing leaf-level changes at the whole-crop level is valuable for guiding fundamental discoveries and crop improvement.

P4.30 INTEGRATING LIVE CONFOCAL MICROSCOPE IMAGERY OF STOMATA WITH MEASUREMENT OF LEAF-LEVEL PHOTOSYNTHETIC GAS EXCHANGE

Friday 7 July 2023 11:30

Jospeph D. Crawford (University of Illinois at UrbanaChampaign, United States), Dustin Mayfield-Jones (University of Illinois at Urbana-Champaign, United States), Glenn A Fried (University of Illinois at Urbana-Champaign, United States), Andrew D.B. Leakey (University of Illinois at Urbana-Champaign, United States)

jcrawfo2@illinois.edu

Stomata are the microscopic pores on plant leaves that open or close to regulate the flux of water from leaves. Guard cells of stomata are known to react to environmental conditions such as light and CO2 in order to optimize CO2 uptake and water loss. Stomatal anatomy

(aperture, length, width, etc.) influences leaf-level physiology traits including conductance to water. Stomatal anatomy can be visualized in situ by microscopy, but the difficulty of regulating the atmospheric environment of a microscope stage means that the conditions under which imaging is done are rarely physiologically relevant. Alternatively, portable photosynthesis measuring instruments offer a non-destructive estimate of leaf gas exchange, including stomatal conductance, while the leaf experiences tightly controlled steady-state or dynamic environmental conditions. However, these measurements reflect stomatal characteristics in aggregate on a leaf area basis, which are heavily influenced by the mesophyll as well as epidermal structure and function. Observing the behavior of stomata by microscopy simultaneous to controlling the leaf environment and measuring gas exchange fluxes would allow advances in the understanding of leaf structure-function relationships. To reconcile the microscopic stomatal characteristics with leaf-level gas exchange we have combined laser scanning confocal microscopy and gas exchange instruments to simultaneously observe stomatal characteristics (e.g. stomatal aperture, pore depth, closing speed) and leaf-level traits like photosynthesis, transpiration, and stomatal conductance. Results are presented for the use of this approach on diverse plant species.

P4.33 IMPLEMENTATION OF A 3D FSPM TO EVALUATE IN SILICO THE SENSIBILITY OF SHORT-TERM WATER USE EFFICIENCY TO PLANT PARAMETERS.

Friday 7 July 2023 12:00

Mona Giraud (Forschungszentrum Jülich GmbH, Germany), Samuel Le Gall (Forschungszentrum Jülich GmbH, Germany), Guillaume Lobet (Forschungszentrum Jülich GmbH, Germany), Andrea Schnepf (Forschungszentrum Jülich GmbH, Germany)

m.giraud@fz-juelich.de

P4.31

ENGINEERING STOMATAL PATTERNING IN PLANTS FOR ENHANCED WATER USE EFFICIENCY – INSIGHTS FROM BEGONIA MODELS

Friday 7 July 2023 11:45

Thu T.P. Ly (University of Glasgow, United Kingdom), Konstantinos Athanasiadis (University of Glasgow, United Kingdom), Catherine Kidner (RBGE Edinburgh, United Kingdom), Rucha Karnik (University of Glasgow, United Kingdom)

2568972L@student.gla.ac.uk

Globally, agricultural freshwater usage has surged 6-fold in the past 100 years, twice as fast as the human population, and is expected to double again before 2030, driven mainly by agriculture. In the UK, irrigation has risen 10-fold in the past 30 years, and this trend is anticipated to continue. Stomata of plants are microscopic pores driving plant gas and water exchanges with the environment. Stomatal behaviors, including movement, density, and patterning, impact photosynthetic rates by over 50% when demand exceeds water supply, exerting a major influence on the water and carbon cycles of the world. Plant water use efficiency (WUE), defined as the amount of dry matter produced per unit of water transpired is directly related to stomatal function. Engineering stomata for enhanced water use efficiencies is of the highest importance in improving crop performance. Begonia species of plants display unique stomatal patterns which help reduce water loss and ensure plant survival under diverse climate conditions. The molecular mechanisms which control these patterns in Begonia are yet unsolved, but they potentially hold valuable knowledge for stomatal development. Studies in Arabidopsis models have shown that stomatal behaviors are determined by secreted peptide signally cascades regulating differentiation. To gain insights into the evolution of behavioral traits of stomata we use gene mining, structure-function studies and physiology analysis of development-related proteins isolated from Begonia conchifolia and Begonia plebeja. Our analysis suggest that characteristic stomatal patterning mechanisms could be linked to the evolution of distinct structural motifs for developmentrelated genes in Begonia species.

Models simulating semi-mechanistically the spatio-temporal interactions between water and carbon fluxes in the soil-plantatmosphere continuum can yield emerging processes, like plant water use efficiency (WUE, structural carbon gain-to-transpiration ratio) of yet non-existing genotype-environment-management combinations. These in silico observations can help breeders focus on the plant characteristics which influence the most agricultural-relevant properties for specific scenarios.

We implemented the novel 3-dimensional Functional Structural Plant Model CPlantBox. CPlantBox can simulate the coupled plant water flow, photosynthesis, and stomatal regulation; the carbon flow and usage; and the resulting cell turgor- and carbon-limited growth. We calibrated CPlantBox for a generic C3 monocot and ran Sobol’s global sensitivity analysis to evaluate the influence of main structural and functional parameters on the WUE. The analysis was run for one time step (3hrs) under two weather scenarios (wetter and colder against drier and warmer) 10 and 20 days after sowing.

The structural parameters (especially leaf blade width and basal root growth rate), and thus the initial plant shape, had a stronger influence on the WUE than most functional parameters. Nonetheless, the mesophyll hydraulic conductance and symplast osmotic potential strongly influenced the cell’s turgor pressure and, consequently, the WUE. Finally, parameters defining the active phloem sucrose loading affected the growth more than those defining the other sucrose sinks. The following steps of the work will include the setup of a calibration pipeline which will incorporate a sensibility analysis of longer simulations’ outputs.

P4.33 DYNAMIC STOMATAL RESPONSES AND YIELD UNDER DROUGHT STRESS IN DOMESTICATED AND WILD TOMATO

Friday 7 July 2023

12:15

Menachem Moshelion (The Hebrew University of Jerusalem, Israel), Yaniv Lupo (The Hebrew University of Jerusalem, Israel), Sanbon C Gosa (The Hebrew University of Jerusalem, Israel)

menachem.moshelion@mail.huji.ac.il

This study investigated the water balance responses of domesticated and wild-tomato species to drought stress. The wild-tomato (Solanum pennellii), a domesticated line (M82) and their introgression lines population (IL lines) were compared using a gravimetric functionalphenotyping platform and a reverse-phenotyping method under well-watered and water-deficit conditions.

Our findings revealed that the domesticated line had a higher stomatal-conductance rate compared to the wild-tomato, resulting in early exposure to drought stress. In contrast, the wild-tomato maintained higher soil water by maintaining lower steady rates of whole-canopy stomatal-conductance. The wild-tomato also exhibited highly plastic daily stomatal-conductance with maximal stomatal apertures peaking early in the day, even under water-deficit conditions. Additionally, the wild-tomato had higher molecular and agronomic water use efficiency due to its higher maximum rate of rubisco activity.

We also identified a few physiological profiles of ideotype as well as survivable lines by comparing the dynamic whole-plant waterregulation responses of the IL lines with several years of yield performance in commercial fields. The ideotype lines presented highly plastic stomatal conductance and high abaxial to adaxial stomatal density ratios, with maximal stomatal apertures peaking early in the day, even under water-deficit conditions. These traits resulted in dynamic daily water-use-efficiency, which resembled the wild-tomato. Moreover, the ideotype physiological profile revealed rapid recovery of transpiration when irrigation was resumed after a period of imposed drought.

Our results indicate that daily stomatal-conductance plasticity is crucial for plant adaptation and productivity under drought stress. This dynamic response could be a useful yield predictor trait in droughtstress conditions.

P5 - EXOCYTOSIS IN PLANT CELLS

ORGANISED BY: MADS EGGERT NIELSEN (UNIVERSITY OF COPENHAGEN), MIKE BLATT (UNIVERSITY OF GLASGOW), VIKTOR

ŽÁRSKÝ (CHARLES UNIVERSITY AND THE INST. OF EXPERIMENTAL BOTANY)

P5.1 A REVISED MODEL OF THE ER/ PRE-GOLGI INTERFACE: TOWARDS THE IDENTIFICATION OF THE INTERMEDIATE COMPARTMENT IN ARABIDOPSIS

Wednesday 5 July 2023 09:00

Yohann Boutté (CNRS, France), Louise Fougère (Bordeaux University, France), Yoko Ito (Ochanomizu University, Japan), Magali Grison (CNRS, France), Patricia Laquel (CNRS, France), Matheus Montrazi (Bordeaux University, France), Fabrice Cordelières (Bordeaux Imaging Centre, France), Christel Poujol (Bordeaux Imaging Centre, France), Akihiko Nakano (RIKEN Center for Advanced Photonics, Japan)

yohann.boutte@u-bordeaux.fr

In eukaryotic cells, the secretory system is a set of membrane compartments that plays fundamental functions to organize and ensure the accuracy of the delivery fluxes of proteins and lipids from the endoplasmic reticulum (ER) to their final destination. The first carry away of this system occurs at the endoplasmic reticulum (ER)export sites (ERES) that convey proteins to the Golgi apparatus. In animal cells, the ERES produces tubulo-vesicular transport carriers that constitute the ER-Golgi intermediate compartment (ERGIC). In plants, the existence of the ERGIC is debated. Due to that the Golgi apparatus is usually found in close proximity of the ER, the current governing idea is that the Golgi apparatus establishes membrane contact sites with the ERES. However, the existence of an ER-Golgi intermediate compartment was suggested using the Golgi-disrupting drug BrefeldinA (BFA) and named Golgi Entry Core Compartment (GECCO). A hurdle is now to address whether an ERGIC exists in native untreated cells and identify its nature, structure and function. In this work, we employed a combination of quantitative label-free proteomics of immuno-purified compartments, improved resolution airyscan microscopy coupled with dynamic tracking of Golgi entities in living cells, lifetime tau-STED super-resolution microscopy and novel imaging quantification methods. Our work proposes a complete reevaluation of the ER-Golgi interface in plant cells and transform previous thinking in this field by deciphering the dynamics and structure of the potential ERGIC in plant cells.

P5.2 GREASING THE WHEELS OF TRANSPORT: THE EVOLUTION AND THE ROLE OF LIPID-PROTEIN INTERACTIONS IN PLANT EXOCYST COMPLEX

Wednesday 5 July 2023 09:30

potocky@ueb.cas.cz

The molecular processes at the border between the plasma membrane and cytoplasm are crucial for many aspects of plant cell life. Despite this, we know surprisingly little about the crosstalk and evolutionary dynamics between membrane lipids and peripheral membrane proteins. Targeted secretion of the plasma membrane and cell wall material drives plant cell polarity and morphogenesis. The exocyst, a conserved eukaryotic hetero-octameric protein complex, assists in the targeted delivery of exocytosis vesicles to specific plasma membrane domains and is an ideal model for protein-lipid interface studies. Remarkably, the membrane-binding exocyst subunit EXO70 underwent extraordinary diversification during plant evolution. Our work aims to shed new light on plant exocyst evolution and its multiple roles at the plant membranes. By combining evolutionary analyses, genetics, live-cell imaging, biochemistry, protein structure modelling, and molecular dynamics simulations, we show the distinct functions of plant exocyst subunits in recruiting the complex to the plasma membrane. We demonstrate that in plants, several signature lipids orchestrate the exocyst recruitment to the plasma membrane, and their action is mutually substitutable. Finally, we present the data addressing the functional origins of the plant EXO70 subfamilies.

Wednesday 5 July 2023 10:00

Martin Potocký (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic)

P5.3 EXO70H4 EXOCYST SUBUNIT AND MLO PROTEINS INTERACT AND PARTICIPATE IN A SECONDARY TRICHOME CELL WALL BIOGENESIS AND DEF

George A Caldarescu (Experimental Plant Biology Charles University, Czech Republic), Jan W Huebbers (Institute for Biology I RWTH, Germany), Zdeňka Kubátová (Experimental Plant Biology Charles University, Czech Republic), Peter Sabol (Experimental Plant Biology Charles University, Czech Republic), Hannah Kuhn (Nstitute for Biology I RWTH, Germany), Ralph Panstruga (Institute for Biology I RWTH, Germany), Viktor Žárský (Experimental Plant Biology Charles University, Czech Republic)

caldareg@natur.cuni.cz

Exocyst is an evolutionarily conserved multi-subunit CATCHR-type tethering protein complex that targets exocytotic vesicles to the PM including localised cell wall modifications in defence against pathogens. EXO70H4 subunit (one of 23 paralogs) is essential for trichomes maturation, including docking the callose synthase at the plasma membrane, callose deposition and secondary cell wall biogenesis. MLO proteins are recently uncovered as bivalent cations channels, and some isoforms such as MLO2, MLO6, and MLO12 play an essential role in powdery mildew susceptibility.

Examining and comparing the biogenesis of the Arabidopsis trichomes secondary cell wall in LOF mutants of EXO70H4 vs MLO2, MLO6 and MLO12 triple mutant, we found that phenotypic deviations associated to the secondary cell wall biogenesis are almost identical.

This phenotype similarity encouraged us to examine if EXO70H4 interacts with MLOs in the secretory pathway and if they are together involved in secondary cell wall biogenesis. We examined transgenic lines expressing fluorophore-labelled EXO70H4 and MLO, demonstrating an extensive co-localisation at the plasma membrane and the cell wall. The localisation of EXO70H4 in themlotriple mutant is disrupted compared to Col-0 and vice versa - MLO6 is mislocalized in exo70H4mutant.

Investigation of the motility (affected by the tethering) of callose synthase PMR4 compartments, revealed enhanced motility in the mlo triple mutant compared to Col-0, similarly as in exo70H4 mutant. Finally, protein-protein interaction assays demonstrated direct interaction between EXO70H4 and MLO6 and more general interaction of specific EXO70 paralogs and MLO isoforms in defence.

P5.4 MOSS PHYSCOMITRIUM PATENS EXOCYST SUBUNITS SEC3 AND SEC15 AS A MORPHOGENETIC AND DEVELOPMENTAL FACTORS

Wednesday 5 July 2023 10:15

Lucie Brejšková (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Samuel Haluška (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Anamika Ashok Rawat (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic), Viktor Žárský (Institute of Experimental Botany of the Czech Academy of Sciences, Czech Republic)

brejskova@ueb.cas.cz

Plant morphogenesis and development are tightly regulated processes based extensively on the cellular polarity determination involving cytoskeleton and endomembrane regulators. Exocyst is a secretory vesicle tethering octameric complex facilitating a wide range of morphological processes in plants. SEC3 subunit interacts directly via its PH domain with the PI(4,5)P2 plasma membrane lipid and SEC15 subunit is known to interact with RAB GTPase. Physcomitrium has three SEC3 and two SEC15 homologues (Arabidopsis has just two

from each). Both mutants in SEC3 and SEC15 loci show similarities in deviations with other moss exocyst mutants - concerning phyllid morphogenesis, cell size, shape, defective sporophytes and aberrant deposition of cuticular waxes. Insec3a, sec3bandsec3cmutant strains, however we also observed phenotypic deviations indicating possible antagonistic regulatory behaviour of these paralogs - SEC3 mutants of A vs. B/C subunits displaying opposite deviations during protonema differentiation. Based on our phylogenetic reconstruction, we will discuss SEC3 gene duplication like a possible neofunctionalization in the context of bryophytes protonema evolution and on the other side both SEC15 subunits as closely related paralogs resulting from terminal duplication, from which one seems to functionally prevail.

P5.5 ESTABLISHMENT AND REGULATION OF CELL POLARITY IN POLLEN GRAINS OF ARABIDOPSIS THALIANA

Wednesday 5 July 2023 11:00

Philipp Denninger (TU Munich, Germany)

philipp.denninger@tum.de

Polar growth is crucial for many cellular and developmental processes. It requires the polar accumulation of growth factors at a specific site within the cell. Often, polar growth is the result of signalling processes, initiated by external cues. However, the initial processes leading to the polar accumulation of proteins and the activation of growth are still not understood. Our research focuses on these mechanisms, and we use pollen germination as a model. This dormant cell establishes ade novopolar growth domain at the contact site with the floral tissue after cell-cell communication and signal perception. The initiated polar growth requires multiple feedback loops to balance cellular expansion and stabilising mechanisms. The RhoGTPases RHO OF PLANTS (ROPs) are central molecular switches that integrate these feedback loops. Their activity is, amongst others, regulated by activating ROP GUANINE NUCLEOTIDE EXCHANGE FACTORS (ROPGEFs). Even though multiple ROPGEFs are present in pollen grains, our studies show that specific ROPGEFs are crucial for polar pollen germination. The proteins are responsible for establishment of a polar domain, activation of ROP signalling and thus male fertility. We describe the timing of polarity establishment and analysed the molecular features responsible for ROPGEF accumulation. Further, we investigate novel phosphorylation sites of ROPGEFs that regulate their activity and could show that both, release of negative regulation and activation of positive regulation are required for ROPGEF function and polar growth initiation.

Wednesday 5 July 2023 11:30

Fatima Cvrckova (Charles University, Czech Republic), Anezka Baquero Forero (Charles University, Czech Republic), Eva Kollarova (Charles University, Czech Republic), Helena Kocova (Charles University, Czech Republic), Denisa Oulehlova (Charles University, Czech Republic)

fatima.cvrckova@natur.cuni.cz

P5.6 PLANT CLASS I FORMINS IN THE ENDOMEMBRANE SYSTEM: THE MODEL CASE OF ATFH1

Formins, or FH2 proteins, are evolutionarily conserved cytoskeletal organizers with actin nucleation and capping abilities. Due to additional domains, they can also engage in other processes such as microtubule dynamics, membrane trafficking and signalling. There are two FH2 protein clades in angiosperms – Class I and Class II formins, the former containing mostly transmembrane proteins that can link the cortical cytoskeleton through the plasmalemma to the cell wall, and possibly also engage in endomembrane dynamics. Several formins from both clades participate in tip growth of root hairs or pollen tubes, suggesting a possible role in exocytosis. AtFH1 (At3g25500) is the most widely expressed Class I formin in Arabidopsis thaliana, previously described as a plasmalemma-localized protein. We observed altered root growth and root hair development under low doses of cytoskeletal inhibitors, as well as changes in epidermal morphogenesis, in atfh1 mutants, consistent with its role in cell expansion. However, we also documented that AtFH1 shows varying intracellular localization along the developmental zones of the root tip, with transient decoration of endosomes and plasmodesmata followed by a brief occurrence on the tonoplast around the time of the central vacuole formation. The spatial arrangement of nascent central vacuoles appears to be altered in atfh1 mutants, indicating a possible role in vacuole development that might also affect turgor-driven cell expansion. In addition, preliminary results of proteomic experiments aiming to identify AtFH1 interactors revealed several components of the endomembrane trafficking machinery, indicating that the membrane-related roles of AtFH1 are not limited to the exocytotic pathway.

P5.7 DOMINANT-NEGATIVE AND MUTANT ANALYSIS OF ARABIDOPSIS SYNAPTOTAGMIN 1 IDENTIFIES SETS OF FUNCTIONAL INTERACTORS

Wednesday 5 July 2023 11:45

Edita Lileikyte (University of Glasgow, United Kingdom)

edita.lileikyte@glasgow.ac.uk

SYNAPTOTAGMIN 1 (SYT1) has been described as an ER-PM contact site regulator in response to abiotic stress with an emphasis to lipid transport for membrane maintenance and repair. These physiological processes are likely associated with vesicular traffic and thus could engage SYT1 with SNAREs, but the evidence for SYT1 association with these trafficking proteins is sparse as is knowledge of its mechanics. We have used the syt1-2 mutant line and identified a dominant negative fragment of SYT1 that impacts on vesicle traffic as well as stress physiology. These data complement evidence for interactions with a subset of SNAREs and ion channels in vitro, using yeast SUS assays, and analysis of stomatal gas exchange characteristics in the mutant plant lines. We are now investigating how SYT1 may affect channel function and what are the implications in guard cell control. The results to date support the idea that SYT1 is an important component of the membrane traffic machinery and may stabilise secretory traffic in the face of abiotic stress.

P5.8 NEW ROLES FOR SECRETORY MACHINERY IN CO2-REGULATION OF TRANSPORT IN STOMATAL CONDUCTANCE

Wednesday 5 July 2023 12:00

ZhiYi Yu (University of Glasgow, United Kingdom), Sakharam Waghmare (University of Glasgow, United Kingdom), Lingfeng Xia (University of Glasgow, United Kingdom), Michael Blatt (University of Glasgow, United Kingdom), Rucha Karnik (University of Glasgow, United Kingdom)

z.yu.3@research.gla.ac.uk

Increasing atmospheric CO2 and climate change have a negative impact on crop water use and productivity, thus increasing the scarcity of food and limiting the availability of agricultural land and water resources worldwide. To mitigate these effects of climate change and for food security in the future, it is essential to address the question - How does CO2 affect the plants we depend on? CO2 is a substrate for photosynthesis, and it is acquired through microscopic pores called ‘stomata’ in exchange for transpirational water loss. Plants respond to elevated CO2 through short-term adjustments in stomatal movements and by adapting stomatal development over the long term. CO2 -control of stomatal movements relies on ion transport and net solute flux, driving volume changes in guard cells. Anion efflux and the influx of K+ ions in guard cells controls osmotic volume change. Membrane vesicle traffic partakes in stomatal control by regulating osmotic ion transport through selective addition and removal of transport proteins, and it facilitates membrane plasticity to support reversible changes in cell volume. Despite the wealth of knowledge about stomata, much remains unknown about the mechanics of stomatal regulation by CO2 . We use approaches in molecular cell biology, stomatal physiology and membrane biochemistry to investigate the impact of CO2 on solute transport and the consequences for stomatal function. We are very excited by these findings which suggest a new role for membrane trafficking machinery in the CO2 -control of stomata.

P5.9 A FAVS-BASED METHOD FOR PLANT VESICLE ISOLATION

Wednesday 5 July 2023 12:15

Alice L Baillie (University of Sheffield, United Kingdom), Andrew Herman (University of Bristol, United Kingdom), Emily R Larson (University of Bristol, United Kingdom)

a.baillie@sheffield.ac.uk

Plant cells manufacture a vast array of macromolecules and must deliver them to their appropriate spatial locations for biological functionality. Specific subcellular vesicles have been isolated from plant cells for proteomic analysis using GFP-trap pull-down approaches by tagging known endomembrane proteins with fluorescent proteins. However, there is currently no way to isolate populations of plant vesicles based on their internal protein cargoes as these are inaccessible to the antibodies used in pull-downs. Fluorescence-Activated Vesicle Sorting (FAVS) has been used to isolate vesicles from mammalian cells for analysis of their protein composition but has not been applied in plant systems. We developed a protocol for plant vesicle analysis and isolation by FAVS. We adapted a published vesicle extraction protocol to generate material suitable for sorting, and optimised our approach using fluorescent markers for known, abundant Golgi/ post-Golgi compartments. We demonstrated that it is possible to sort these samples based on their fluorescent signatures, quantify the size and relative abundance of labelled compartments, and collect material for downstream applications such as proteomics. We also developed recommendations for optimising the design of dual fluorescent marker lines to allow comparison of compartments carrying labelled cargo with control populations in which only the

compartments themselves are labelled. Our FAVS-based technique will allow us to answer presently intractable questions about the mechanisms regulating delivery of specific cargos to their dynamic subcellular or extracellular destinations, enhancing our understanding of fundamental plant cell biology, and providing new opportunities to manipulate plant development and growth.

P5.10 PLANT VESICLE TRAFFICKING MACHINERY INTERSECTS GROWTH & IMMUNE RESPONSES

Wednesday 5 July 2023 15:00

Rucha Karnik (University of Glasgow, United Kingdom), Lingfeng Xia (University of Glasgow, United Kingdom), Sakharam Waghmare (University of Glasgow, United Kingdom), Guillermo Baena (University of Glasgow, United Kingdom)

rucha.karnik@glasgow.ac.uk

Discoveries over the past decade have uncovered a close co-ordination between the membrane transport and vesicle trafficking machinery in plants. Such co-ordination impacts plant growth, nutrient uptake and contributes to stomatal regulation. Outcomes of the plant-pathogen warfare depend on stomatal regulation, controlling pathogen entry into the plant and dictating the plant water status. Membrane traffic is also a central player in immunity, for instance the secretion of antimicrobial peptides is essential for pathogen destruction. Plant defence often comes at a cost to growth, therefore understanding the overlap between underlying mechanism is fundamentally important. Recently, we uncovered that a vesicle trafficking SNARE partakes in functional regulation of the plasma membrane (PM) H+-ATPase proteins, affecting auxin-regulated plant growth. The vesical trafficking machinery is recruited for defence related secretory traffic during pathogenesis. This talk presents our recent work uncovering the divergent nature of the plant vesicle trafficking machinery that intersects plant growth and immune responses.

P5.11 USING PLANT DEFENSE RESPONSES TO UNDERSTAND POLARIZED SECRETION

Wednesday 5 July 2023 15:30

Mads E Nielsen (University of Copenhagen, Denmark), David H Munch (University of Copenhagen, Denmark), Mengqi Liu (University of Copenhagen, Denmark), Hector M Rubiato (Politécnica de Madrid, Spain)

maen@plen.ku.dk

When land plants get attacked by filamentous pathogens that invade by direct penetration through the epidermal cell wall, they respond by forming local cell wall fortifications known as papillae and encasements. The formation of these defense structures requires a member of the conserved SYP12 clade of plant secretory syntaxins that mediates polarized secretion of exosomes, toxic metabolites, and/or antimicrobial enzymes and peptides to block pathogen invasion. Thus, formation of papillae and encasements in Arabidopsisis a useful model system for understanding the molecular machinery underlying polarized

secretion in plants and how this is regulated. We have found that papilla- and encasement formation relies on two, at least partially, independent membrane trafficking pathways as defined by the requirement for GNOM. Interestingly, these defense structures do not accumulate secreted proteins per se, instead we find that recycling plasma membrane imbedded proteins are redirected to the site of attack. Currently, we investigate how this recycling is orchestrated and which signaling cues that determine which proteins end up in the two different defense structures.

P5.12 SMALL MONOMERIC GTPASE RABA2A ONLY INDIRECTLY AFFECTS POLARIZED SECRETION NEEDED FOR PENETRATION RESISTANCE

Wednesday 5 July 2023 16:00

David Havndrup Munch (University of Copenhagen, Denmark), Hector Rubiato (University of Copenhagen, Denmark), Mads Eggert Nielsen (University of Copenhagen, Denmark)

david-munch@plen.ku.dk

Arabidopsis thaliana protects itself against penetrations by the non-adapted filamentous fungal pathogen Blumeria hordei (Bh), by producing papillae and encasement defense structures at sites of attack. While formation of the two defense structures require either of the two syntaxins PEN1 or SYP122, the polarized secretion of papilla and encasement material relies on two independent recycling pathways that are ill defined. One possible regulator is the small GTPase RabA2a, which interacts with PEN1 and SYP122 in mediating recycling and secretion of a subset of proteins to the plasma membrane (PM). However, we observe no immediate effect of DN-RabA2a on formation of papillae and encasement structures or on penetration by Bh. Only after prolonged induction did DN-RabA2a prevent papilla and encasement formation. While this correlated with an increase in penetrations by Bh, it also correlated with a complete absence of both PEN1 and SYP122 at the PM. Interestingly, DN-RabA2a seemed only to affect recycling proteins such as TET8 and PEN3. In contrast, these markers were unaffected in plants lacking PEN1 and SYP122. Accordingly, RabA2a is unlikely to mediate a direct link between papilla/ encasement formation and PEN1/SYP122. Instead, we speculate that RabA2a acts in general recycling of PM proteins which does not need either PEN1 or SYP122.

P5.13 TANGLED EVOLUTION OF PLANT CELL DIVISION ORIENTATION

Wednesday 5 July 2023 16:15

Samuel Haluška (Czech Academy of Sciences, Czech Republic), Edita Janková-Drdová (Czech Academy of Sciences, Czech Republic), Lucie Brejšková (Czech Academy of Sciences, Czech Republic), Martin Potocký (Czech Academy of Sciences, Czech Republic), Viktor Žárský (Czech Academy of Sciences, Czech Republic)

samuel.haluska@gmail.com

The preprophase band (PPB) is considered a structure that robustly stabilizes and predicts the future cell division plane prior to cytokinesis. Interestingly, this cytokinetic structure was probably established within the land plants alongside with the 3D oriented cell division. Previous research, focused mainly on the model plantArabidopsis thaliana, has identified proteins that are involved in the PPB function and establishment of the phragmoplast guiding Cortical Division Zone (CDZ). To shed a new light on PPB evolution, we performed an exhaustive phylogenetic survey of all known PPB-related proteins. We discovered that most of the individual PPB components are already present in Streptophyte algae (not forming the PPB) and that the only Embryophyta taxonomically restricted gene involved in CDZ positioning is the TANGLED with its putative orthologs. We will present data showing the nonlinear TANGLED evolution and the characterization of bryophyte TANGLED function in CDZ establishment.

P5.14 SECRETORY AUTOPHAGYUNCONVENTIONAL PROTEIN SECRETION MECHANISM ALSO IN PLANTS?

Wednesday 5 July 2023 16:15

Viktor

zarsky@ueb.cas.cz

In contrast to animal and yeast cellular models where distinct unconventional protein secretion processes are known and some of them mechanistically well understood on the molecular level, we even do not have an overview of possible candidate unconventional protein secretion phenomena in plant cells. One relatively well characterized mode of unconventional protein secretion in animals is the secretory autophagy able to export from the cytoplasm not only proteins without signal peptide (as e.g. inflammatory cytokine or support insulin secretion), but also other cytoplasmic constituents including organelles. In plant cells decades ago electron microscopist first observed aggregates of vesicles, sometimes with other cytoplasmic constituents as e.g. ribosomes, outside the cell in the apoplast/cell wall – paramural bodies. Such structures are often associated also with the innate immunity defensive papillae formation in plants. It is currently supposed that they are related to exosomes in animal cells and are in fact a secretory re-direction of multivesicular/pre-vacuolar late endosomes. Secretion of specific exocyst complex regulated vesicles bypassing Golgi to the apoplast and recent discovery of the amphisome in plants, both indicate that secretory autophagy is a plausible possibility also in plant cells. Aspects and possible future directions of the analysis of this process in plants will be discussed.

P5.15 FUNCTIONS OF THE EXO84A EXOCYST SUBUNIT IN ARABIDOPSIS POLLEN

Wednesday 5 July 2023 16:15

Lukáš Synek (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic), Eva Kollárová (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic), Martin Potocký (Institute of Experimental Botany Czech Academy of Sciences, Czech Republic)

synek@ueb.cas.cz

Pollen grain germination and pollen tube elongation are crucial biological processes in angiosperm plants that involve polarized secretion. Precise regulation of this process requires the exocyst tethering complex that targets secretory vesicles specifically to the plasma membrane. The exocyst consists of eight subunits, assembled into two modules. We focused on the EXO84 exocyst subunit in pollen and found that out of three EXO84 isoform in Arabidopsis EXO84a represents the main isoform functioning in the male gametophyte. EXO84a interacts in the Y2H system with EXO70 and SEC15 subunits similar to EXO84b in the sporophyte. Mutants in EXO84a generate short pollen tubes that often show an aberrant morphology. EXO84a-GFP is localized in growing tips of pollen tubes similar to other exocyst subunits. We conclude that EXO84a is a crucial component of the exocyst complex in Arabidopsis pollen that is required for ef ficient polarized secretion.

Wednesday 5 July 2023

16:15

Sakharam Waghmare (University of Glasgow, United Kingdom), Lingfieng Xia (University of Glasgow, United Kingdom), Thu Ly (University of Glasgow, United Kingdom), Rucha Karnik (University of Glasgow, United Kingdom)

sakharam.waghmare@glasgow.ac.uk

Plant pathogens inflict severe losses on resources and economy in agriculture. Plants possess an innate ability to overcome pathogens and abiotic stress, but such responses often come at a cost to plant productivity and water use. For instance, microbial pathogens evoke major changes in stomatal regulation and these mechanisms are orchestrated through closely co-ordinated ion flux and membrane vesicle traffic pathways. For defence against pathogens, secretory vesicle traffic is essential for delivery of defence related signalling peptides to the cell wall. How the membrane trafficking machinery tracks pathogen defence signals, and its implications on secretory processes in the plant is an enigma.

We used advanced quantitative Tandem Mass Tag (TMT)- based mass spectrometry analysis of secretome in Arabidopsis leaf tissue following bacterial pathogen challenge to elucidate secretory traffic. The trafficking Soluble N-ethylmaleimide-sensitive-factor attachment (SNARE) proteins in plants, as in all eukaryotes assemble to drive vesicle fusion at the plasma membrane. In Arabidopsis, plasma membrane localised SNAREs SYNTAXIN OF PLANTS 121 (SYP121) and SYP122 drive bulk of secretory traffic together with an evolutionarily ancient SYP132. Recently, we discovered overlapping and independent roles of the plasma membrane SNAREs for secretion in seedlings under standard conditions. To determine how bacterial pathogens affect SNARE-assisted secretory traffic, we used mutant and dominant negative approach to track secretion. Together with analysis of SNARE abundance our data uncovered pathogen-regulated secretome profiles in the plant. We identified new components of the plant secretome, that suggest a role of the trafficking SNAREs in intersecting plant growth and immune responses.

P5.16 SECRETOME PROFILES IN ARABIDOPSIS IN RESPONSE TO BACTERIAL PATHOGEN CHALLENGE UNCOVERS NEW SNARE-REGULATORY NETWORKS.

Žárský (Charles university and Inst. of Exp. Botany CAS Prague, Czech Republic)

P6 - PLANT BIOLOGY FOR SUSTAINABILITY

P6.1 GETTING TO THE ROOT OF SYMBIOTIC ROOT NODULE DEVELOPMENT FOR BIOLOGICAL NITROGEN FIXATION IN PLANTS

Tuesday 4 July 2023 09:00

Katharina Schiessl (University of Cambridge, United Kingdom), T. Lee (University of Cambridge, United Kingdom), M. Orvosova (University of Cambridge, United Kingdom), M. Bueno-Batista (University of Cambridge, United Kingdom), N. Stuer (University of Cambridge, United Kingdom), P.C. Bailey (University of Cambridge, United Kingdom), K.S. Mysore (University of Cambridge, United Kingdom), J. Wen (University of Cambridge, United Kingdom), G.E.D Oldroyd (University of Cambridge, United Kingdom)

katharina.schiessl@slcu.cam.ac.uk

Legumes grow specialized root organs, symbiotic nodules, to host beneficial nitrogen-fixing bacteria that provide the plant with ammonia in exchange for carbon. Exploiting biological nitrogen fixation provides a valuable alternative to industrial nitrogen fixation via the Haber Bosch process, which is a major contributor to global greenhouse gas emissions. In this project we aim to promote and optimise biological nitrogen fixation in our agro-ecosystems by advancing our understanding of how plants can accommodate nitrogen-fixing bacteria. This will contribute to combating climate change and its effect on our food production systems and their security and equity1

Symbiotic nodules are distinct from lateral roots in morphology and function as they comprise of cells that can accommodate nitrogenfixing rhizobial bacteria intracellularly and provide favorable conditions for the biological nitrogen fixation process. Our previous findings that the initiation of lateral roots and nodules converges at a common developmental program2 led to the hypothesis that an additional nodule-specific program is required to determine nodule organ identity on top of the shared root-like initiation program. Here, we show that two members of theLIGHT SENSITIVE SHORT HYPOCOTYL (LSH) transcription factor family (MtLSH1andMtLSH2), predominantly known to define organ boundaries and meristem complexity in the shoot, function as regulators of nodule organ identity. We conclude that the coordinate recruitment of a pre-existing primordium identity program, in parallel to a root initiation program, underpins the divergence between lateral roots and nodules [3].

References:

1. Yhu PLoS Biol 21

2. Schiessl Curr Biol 29 [3] Schiessl bioRxiv 528179

P6.2 EFFECT OF NITROGEN AVAILABILITY ON COLD ACCLIMATION OF ARABIDOPSIS THALIANA PLANTS

Tuesday 4 July 2023 09:30

Armida Gjindali (University of Manchester, United Kingdom), Giles N Johnson (University of Manchester, United Kingdom) armida.gjindali@manchester.ac.uk

As sessile organisms, plants have developed a plethora of mechanisms to cope with changes in their environment, such as fluctuations in light intensity or temperature. These mechanisms aim to best synchronise photosynthesis with whole plant metabolism. Short-term abiotic stress are counteracted by transient protective mechanisms, e.g. non photochemical quenching (NPQ), that dissipate excess energy and are activated andde-activated rapidly when environmental conditions are restored. Sustained environmental change, however, is counteracted via photosynthetic acclimation, a process completed after a few days. Acclimation in already developed leaves is termed dynamic acclimation and includes changes in sustained gene expression and protein content. Being at the forefront of plant growth, photosynthesis is tightly regulated to changes in the environment. Photosynthetic acclimation refers to changes in photosynthetic components that result in alterations in energy absorption and utilisation.In this study, we examine the effect of soil nitrogen availability of Arabidospsis thaliana plants dynamic cold acclimation. In Arabidopsis cold acclimation results in a substantial increase in maximum photosynthetic capacity and leaf protein. In this study we show that high N availability is required for such an up-regulation of carbon assimilation. Plants were grown in three different N concentrations: 2.5, 5 and 15mM total N. Our results show that only plants grown at the highest N concentration can up-regulate their photosynthetic capacity while in plants grown at the lowest N concentration photosynthetic capacity decreased after cold treatment. Measurements ofChla fluorescence parameters and photosynthetic protein levels reveal a distinct response to cold depending on the N condition.

Tuesday 4 July 2023 09:45

P6.3 SCFOSFBK1 E3 LIGASE MEDIATES

JASMONIC ACID INDUCED TURN-OVER OF OSATL53 AND OSCCR14 TO REGULATE RICE ANTHER AND ROOT LIGNIFICATION

ORGANISED BY: DR. LIANA ACEVEDO-SIACA (MICHIGAN STATE UNIVERSITY), DR STEFAN KEPINSKI (UNIVERSITY OF LEEDS)

AISHWARYE SHARMA (Department of Plant Molecular Biology University of Delhi South Campus, India), Pratikshya Borah (Department of Plant Molecular Biology University of Delhi South Campus, India), Arun Kumar Sharma (Department of Plant Molecular Biology University of Delhi South Campus, India), Paramjit Khurana (Department of Plant Molecular Biology University of Delhi South Campus, India), Jitendra Paul Khurana (Department of Plant Molecular Biology University of Delhi South Campus, India)

aishwaryesharma91@gmail.com

Lignin is one of the most important secondary metabolites synthesized by plants. It provides water resistance to vascular bundles, mechanical support to cell walls, and prevents the entry of pathogens in plants.

Cinnamoyl CoA-reductase (CCR) is one of the main enzymes that help in monolignol biosynthesis, which is the structural unit in lignin biosynthesis. We have identified a RING-H2 domain containing protein OsATL53, which interacts with OsCCR14, the Arabidopsis CCR1 ortholog in rice. OsCCR14 knock-down (OsCCR14KD ) plants are known to possess less lignin. To ascertain the role of OsATL53, we raised OsATL53 knock-down (OsATL53KD ) and OsCCR14 overexpression (OsCC14OX ) transgenics. Roots of OsATL53KD and OsCC14OX plants showed increased amounts of lignin. Anthers of OsATL53KD and OsCCR14OX exhibited more u-shaped lignin rings, as compared to wild-type. OsATL53KD plants also accumulated high transcript levels of OsCCR14. These results indicate that OsATL53 might act as a negative regulator of OsCCR14 at both transcript and protein level. OsFBK1, an F-box protein, interacted with both OsCCR14 and OsATL53, and executed their turnover in cytoplasm and nucleus, respectively, in a 26S proteasomal-mediated pathway. This regulation was found to be jasmonic acid dependent. At the cellular level, OsATL53 was observed to act like a payload transporter, and OsATL53 along with OsCCR14 and OsFBK1 accumulate around the nucleus in the presence of jasmonic acid. Also, we show that jasmonic acid induces conformation changes to OsATL53 and OsCCR14. Thus, we demonstrate the possible regulatory functions of OsATL53 and OsFBK1 in lignin homeostasis via OsCCR14 in rice.

P6.4 ROOT RESPONSES TO ABIOTIC STRESS IN WHEAT

Tuesday 4 July 2023 10:00-10:15

Lucia Nevescanin-Moreno (The University of Nottingham, United Kingdom), Riccardo Fusi, Craig Sturrock, Brian Atkinson, Simon Griffiths, Sacha Mooney, Francisco Pinto, Bipin Pandey, Matthew P. Reynolds, Malcolm Bennett.

antonia.nevescaninmoreno@nottingham.ac.uk

Wheat is a vital crop for ensuring global food security, as it provides a significant portion of the world's dietary calorie and protein intake. At current rates, wheat production will be insufficient to meets the needs of a growing population. Moreover, wheat is susceptible to environmental stress and soil compaction, and therefore global production is being threatened by global climate change and the use of heavy machinery in modern agriculture practices. Current strategies in wheat breeding are aiming to overcome such limitations. However, such strategies oftentimes ignore plant roots, despite being a key factor determining the access to resources in soil. This work aims to 1) identify the root traits involved in plant performance under drought and heat stress, and 2) investigate the natural variation in wheat's root ethylene response and its potential for adapting to soil

compaction conditions. For the environmental stress field trials, we set a panel of 14 genotypes under yield potential, water deficit and a late sowing to achieve heat stress. Root biomass and root architecture traits were measured and then correlated with agronomic traits, from which we found root biomass distribution present a higher effect in in plant performance than root structural traits. For the soil compaction experiment, we developed a bioassay for ethylene sensitivity to assess root growth inhibition in a subset of the A.E. Watkins collection and then contrasting lines were tested in different bulk densities revealing that compaction resistance correlates with reduced root ethylene sensitivity.

P6.5 DISTURBANCE AND HOMEOSTASIS OF THE PHYLLOSPHERE MICROBIOTAIDENTIFICATION OF POSSIBLE TRAITS FOR IMPROVEMENT OF BENEFICIAL MICROBIOME RESILIENCE

Tuesday 4 July 2023 10:15

Paul F Devlin (Royal Holloway University of London, United Kingdom), Stacey A Vincent (Royal Holloway University of London, United Kingdom), Eleanor L Gascoyne (Royal Holloway University of London, United Kingdom), James A O'Rourke (Royal Holloway University of London, United Kingdom), Andreas Ebertz (Royal Holloway University of London, United Kingdom), Pietro D Spanu (Imperial College London, United Kingdom)

paul.devlin@rhul.ac.uk

Current heavy use of pesticides including fungicides in agriculture is leading to soil and watercourse pollution concerns. Exploitation of the plant-protectant properties of the plant microbiome provides a more sustainable approach. However, a key obstacle to microbiome exploitation is the difficulty in establishing engineered microbiomes in the field due to the disruptive effect of environmental stress and/or simultaneous agrichemical application. This is particularly true in the aerial parts of the plant, the phyllosphere, where leaves and stems are exposed to the elements, while the lack of a stably-colonising reservoir of microbes in the absence of surrounding soil further exacerbates this problem. Understanding how we can engineer resilience within a microbiome is crucial. We have used a next generation sequencing approach to investigate the phyllosphere bacterial microbiome under a range of environmental stresses and in plants exhibiting constitutive stress responses. While all treatments caused dramatic alteration in community diversity within both endophytic and total phyllospheric bacterial communities, we found evidence of a stable core microbiome. We argue that plants profit from a phyllosphere microbial community that has co-evolved to allow it to withstand stress responses. Predictive metagenomics have revealed an enrichment of specific traits among this core community, providing insight into features that could have been selected for during that coevolution to promote stability. Further studies on the effects of agrichemicals will also be presented towards an ultimate goal of helping engineer better crop protection methods by enabling the stable establishment of a microbiome-based hybrid plant protection approach.

P6.6 MODELS-GUIDED CROPPINGSYSTEM DESIGN FOR SUSTAINABLE AGRICULTURE: INSIGHTS FROM THE BREEDING PROGRAMS AT ICRISAT

Tuesday 4 July 2023 13:30

Jan Pavlík (Czech University of Life Sciences Prague, Czech Republic), Sunita Choudhary (International Crops Research Institute for Semi-Arid Tropics, India), Amir Hajjarpoor (Julius Kühn-Institut, Germany), Jan MasnerCzech (University of Life Sciences Prague, Czech Republic), Vincent Garin (International Crops Research Institute for Semi-Arid Tropics, India), Madina Diancoumba (International Crops Research Institute for Semi-Arid Tropics, India), Swarna Ronanki (Indian Institute of Millets Research, India), Jan Jarolímek (Czech University of Life Sciences

Prague, Czech Republic) Michal Stočes (Czech University of Life Sciences Prague, Czech Republic)

J.Kholova@cgiar.org

The climatic changes are projected to threaten food security, especially in the most fragile agri-systems like semi-arid tropics. The stabilization/ improvement of such complex systems requires a quantitative understanding of the system dynamics and the data integration at multiple levels of the agri-food-system continuum. Much of such agrisystem designing is being done in-silicousing the crop growth models (CGMs) which integrates biophysical knowledge of the cropping system continuum and enables analysis of its dynamics across the relevant spatio-temporal scales. We'll show several case-studies where CGMs guided the effective cropping system design (GxExM optimization). Consequently, we'll show how such crops can be rapidly developed in breeding program using range of phenomics tools.

The common denominator of these approaches - modelling and phenomics - is the big data which is typically produced in the process. This implies, the biological disciplines have to be effectively integrated with data sciences at numerous levels; the data has to be automatically acquired, stored, processed in the efficient and standardized manner and provided to the end user in a comprehensive way. We'll showcase some of our current aims to overcome gaps related to big data analytics and tools to communicate the results to the next user effectively. We'll also highlight cases where the modelling and ITC outputs adoption by the practitioners enabled systematic-changes in strategy towards improvement of dry-land cereals and legumes-based cropping systems.

We'll open the discussion on the future directions related to integration of in-silico methods and data sciences in support of sustainable cropping system improvement.

The future of agriculture and global food security is threatened by the limited supply and use of water, particularly as climate uncertainty increases. Developing crops that are more efficient in their use of water is essential for global food security. Understanding water use efficiency (WUE), which is the amount of biomass produced per unit of water consumed, is critical for creating climate-smart crops. Previous efforts to improve WUE have focused on the stomatal function, assessed through gas exchange measurements at a leaf or canopy level. However, the contribution of xylem arrangement and aquaporin function to WUE is not well understood. In this talk, I will address this knowledge gap by examining the role of xylem and aquaporins in WUE in cereal crops, which can eventually lead to the development of more efficient and sustainable crops.

P6.8 IDENTIFICATION AND CHARACTERIZATION OF THE GENE REGULATORY NETWORK CONTROLLED BY HVNAC6 DURING GRAIN DEVELOPMENT AND ABIOTIC STRESS

Tuesday 4 July 2023 14:15

Jos HM Schippers (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Isabel Mora-Ramírez (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Keerthana Nagesh (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Anne Ziplys (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Johannes Thiel (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany)

schippers@ipk-gatersleben.de

Current climate change requires increased breeding efforts for resilient plants that can maintain their yield potential under environmentally challenging conditions. To do so, a detailed understanding is required of the underlying molecular networks that regulate plant development and adaptation during stress. Here, HvNAC6, a member of the plant-specific NAC transcription factor family known for their role in development and stress responses, was characterized in detail.

HvNAC6 is tissue-specifically expressed during barley grain development. In addition, the expression of HvNAC6 is readily induced by different abiotic stresses. To reveal the downstream gene regulatory network of HvNAC6 a DNA-affinity purification (DAP) sequencing approach was performed on genomic DNA libraries obtained from three different time points during grain development. This analysis uncovered a plethora of potential target genes of HvNAC6 during grain development. In addition, established HvNAC6 RNAi lines were used in a RNA-seq approach to determine the impact of HvNAC6 on the transcriptional program underlying grain development. By comparing the transcriptome data with the genome-wide DNA binding profiles we were able to identify direct transcriptional targets of HvNAC6 during grain development.

Tuesday 4 July 2023 14:00

Pallavi Singh (University of Essex, United Kingdom)

pallavi.singh@essex.ac.uk

Furthermore, the role of HvNAC6 during salt stress and heat stress was explored, especially the latter as heat shock-related genes appear to act downstream of HvNAC6 during grain development. This analysis indicates that HvNAC6 is a positive regulator of abiotic stress tolerance. Currently, the impact of HvNAC6 on grain yield in barley is being studied to understand if it could be a useful tool for improving barley productivity under stress conditions.

P6.7 RISING WITH THE FLOW: MAXIMIZING PLANT RESILIENCE BY EXPLORING THE CONNECTION BETWEEN VASCULAR STRUCTURE, AQUAPORINS AND WATER USE EFFICIENCY IN CEREAL CROPS.

P6.9 THE SIGNIFICANCE OF THE CAP-BINDING COMPLEX IN BARLEY'S ADAPTATION TO ABIOTIC STRESS

Tuesday 4 July 2023 14:30

Ewa Sybilska (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland), Wiktoria Fus (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland), Marek Marzec (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland), Agata Daszkowska-Golec (Institute of Biology Biotechnology and Environmental Protection University of Silesia in Katowice, Poland)

ewa.sybilska@us.edu.pl

Plants are constantly subjected to multiple adverse environmental stresses during the whole lifecycle. Abscisic acid (ABA) is the main phytohormone that regulates plants’ adaptation to abiotic stresses. As a seed germination inhibitor, ABA also enables seeds to survive unfavorable conditions. Promising genes for research focused on plant stress responses are the negative regulators of the ABA signaling - CBP20 (Cap-Binding Protein 20) and CBP80. These genes encode the small and large subunits of the CBC (Cap-Binding Complex), which functions in RNA metabolism and alternative splicing. However, the knowledge regarding the role of CBC in the ABA signaling pathway in important crop species such as barley (Hordeum vulgare) remains unknown. We conduct experiments using a unique hvcbp20.ab/ hvcbp80.b double mutant with single hvcbp20.ab and hvcbp80.b and its parent cv. ‘Sebastian’. At different stages of development, physiological, molecular, and transcriptomics analyses are performed in response to drought stress and ABA. The obtained results of the drought experiment at the seedling stage indicate a better adaptation of the hvcbp20.ab/hvcbp80.b compared to WT, which is similar to the single mutants. However, intriguing is the response of the double mutant to ABA at the seed germination stage, which seems to be similar to WT, but differs from the single mutants. Conducting the transcriptomic analyses at the gene and transcript expression level allows us to identify differentially expressed genes (DEG), transcripts, and splicing isoforms that may be significant for explaining the hvcbp20. ab/hvcbp80.b phenotype.

P6.10 NITRATE-INDUCIBLE ATNAC2 TRANSCRIPTION FACTOR REGULATES ROOT GROWTH IN GLYCINE MAX L.

Tuesday 4 July 2023 14:45

Hien Van La (Thai Nguyen University of Agriculture and Forestry, Vietnam)

hiencnsh87@gmail.com

Modulation of the root system architecture, including primary root growth and branching, is the most essential plant that uses nitrogen availability in the soil. However, the mechanism pathway coordinating the adjustment of root growth in response to distinct crosstalk between nitrate and AtNAC2 transcription factors remains unclear. Here, we show that downregulation of AtNAC2 in roots correlates with decreased growth of meristem cells, thereby shortening root length. The AtNAC2 mutant upregulated response to nitrate and auxin treatments, increased

primary root growth, and promoted lateral root emergence to build a highly branched root system in soybean. Auxin accumulation in root-derived nitrate availability in roots is epistatic upstream of auxin synthesis. AtNAC2 functions as an integrator of nitrate and auxin signaling in promoting root growth. The regulatory role of AtNAC2 in primary and lateral root growth is dependent on nitrate assimilation and uptake, and it acts upstream of nitrate-associated genes nitrate reductase (GmNR) and nitrate transporter 1.1 (GmNRT1.1). Additionally, AtNAC2 coordinated IAA signaling-associated genes transport inhibitor response (GmTIR1) and auxin/indole-3-acetic acid (GmAux/IAA) to repress auxin-responsive factor (GmARF2) in the auxin signaling pathway. This novel nitrate-AtNAC2-auxin model provides new insights into the understanding of NAC transcription factors and crosstalk between nitrate and auxin signaling pathways. These results suggest that AtNAC2 is an exciting gene resource for breeding high-yield crops with more efficient use of fertilizer.

P6.11 EXPLORING THE FUTURE OF COASTAL AGRICULTURE: SHORTDURATION SIMULATED SEAWATER FLOODING AFFECTS MORTALITY, GROWTH, AND YIELD IN FOUR COMMON CROPS

Tuesday 4 July 2023 14:45

Cally D. Barratt (University of Plymouth, United Kingdom), Mick E. Hanley (University of Plymouth, United Kingdom), Richard C. Thompson (University of Plymouth, United Kingdom), Iris Möller (Trinity College Dublin, Ireland)

cally.barratt@plymouth.ac.uk

Background and Aims: Coastal zones are dynamic areas influenced by both marine and terrestrial environments. Climate change, and the resultant increase in extreme weather events, will have substantial impacts on these landscapes. One of the most prominent threats to coastal territories is storm surge flooding, and alarmingly, many nations rely on these areas for agricultural use. This could have detrimental impacts on food security in flood prone zones such as low elevation coastlines. The scope of this study is to explore potential avenues for developing resilience in arable cropping systems based in coastal regions by assessing the effects of acute seawater flooding on selected common crop species.

Methods: Selected crops (Brassica napus, Hordeum vulgare, Oryza sativa, Triticum aestivum) cultivated under greenhouse conditions, were flooded with a seawater substitute, at three separate growth stages, for either 24hrs or 96hrs with a 0hr control. The impact of simulated short-duration storm surge flooding on plant mortality, development, and yield was monitored thereafter. This allowed results to be related to both exposure times and inherent vulnerability connected to ontogeny. Two cultivars were used per crop to incorporate limited genetic variety into observable responses. Replicates were limited to 10 plants per treatment group.

Results: A significant effect was observed on growth following immersion in all four crop species at each growth stage, with average biomass decreasing substantially up to 28 days post-exposure. Mortality and yield varied between flood times and growth stages for each crop but results predominantly indicated a negative response in flooded plants.

P6.12 A REVIEW OF THE ROLE OF METABOLITES IN VEGETATIVE DESICCATION TOLERANCE OF ANGIOSPERMS

Tuesday 4 July 2023 14:45

Ademola E. Adetunji (University of Cape Town, South Africa), Halford J W Dace (Wageningen University and Research, Netherlands), John P Moore (University of Stellenbosch, South Africa), Jill M Farrant (University of Cape Town, South Africa), Henk WM Hilhorst (Wageningen University and Research, Netherlands)

adetunjiademola@hotmail.com

Desiccation tolerance (DT) is a rare ability in vegetative organs of plants, but it is common in reproductive structures. Resurrection plants, however, possess vegetative DT, with mechanisms similar to those found in reproductive structures, implying a common genetic and evolutionary basis for plant DT. Desiccation-tolerant angiosperms regulate responses at different levels (cellular, proteomic, and metabolic) to survive extreme water deficit stress. This review surveys the state of knowledge about the anhydrobiotic metabolome in angiosperms, highlighting important areas of uncertainty and proposing experimental directions that may help fill gaps in our knowledge of how metabolic shifts contribute to anhydrobiosis. The review provides an inventory of desiccation-related metabolites in different species. Sugars, such as sucrose and raffinose family oligosaccharides, are key to the desiccation response in many species, and trehalose is critical forMyrothamnus flabellifoliaand various non-angiosperm resurrection plants. Other carbohydrate changes include increased sugar alcohols inXerophyta viscosaand decreased monosaccharides in most species. Amino acid profiles show a variety of responses in various clades of resurrection plants. Proline acts as an osmoprotectant in some species during early drying responses, but its accumulation during DT is not universal. Serine depletion is observed in many species, but it is still unknown whether this is because it becomes harmful or because it is a precursor to some other important metabolites. Overall, this review provides insights into the regulation of various metabolites in relation to DT in various species and proposes future directions for research.

adhip143@gmail.com

Rising global air temperature would be one of the major limitations for world's food production in future. High temperature levels cause harmful effects on growth, quality and yield of rice (Oryza sativa L.), affecting their overall production. Higher spikelet fertility is the most desirable traits for mitigating effects of climate change and may be focused for developing rice varieties with climate resilience under future scenario for sustainable rice productivity globally. In this context, identification of efficient genotypes and introgression of candidate genes in the cultivated varieties is utterly important and seems a way to restrain significant yield losses. In our study, spikelet fertility and panicle weight were investigated for two years in a set of 241 rice genotypes sequenced under 3000 rice genome project, under natural and controlled environmental conditions. High temperature significantly reduced the spikelet fertility and panicle wight. Genome wide association mapping was performed on spikelet fertility and panicle weight with 1 million SNPs using an efficient mixed model. A total of 134 QTLs were found associated with spikelet fertility and 155 QTLs with panicle weight under high temperature stress. Putative candidate genes and their haplotype variants have been identified. The work facilitates developing haplotypes, haplotype networks, haplotype specific markers and identification of genotypes carrying superior haplotypes. The identified haplotypes could be beneficial for marker-assisted breeding and making reproductive stage high temperature stress tolerant rice.

P6.14 USING MONOCOT GRAFTING TO BREAK THE SPECIES BARRIER

Tuesday 4 July 2023 14:45

Anoop Tripathi (University of Cambridge, United Kingdom), Julian Hibberd (University of Cambridge, United Kingdom) at925@cam.ac.uk

Grafting is the horticultural practice of fusing two plants so that they grow as one. However, this ancient and widespread agricultural practice had not been applied to the monocotyledons, which include many cereal crops. Our recent work has overturned the consensus dating back thousands of years that grasses and related species do not graft. We identified that the hypocotyl (mesocotyl in grasses) as a meristematic tissue allowing grafting. I will outline the process of monocot grafting and how these findings open-up grafting as a research tool to understand plant physiology, development, and genetics in numerous annual and perennial monocots. Future research could explore the potential benefits of monocot grafting in improving crop yields and resilience to environmental stresses.

Tuesday 4 July 2023 14:45

Adhip Das (Icar-Indian Agricultural Research Institute, India), Anthony J. Travis (School Of Biological Sciences University

Of Aberdeen, United Kingdom), Adam H. Price (School Of Biological Sciences University Of Aberdeen, United Kingdom), Ranjith K. Ellur (Division Of Genetics Icar-Indian Agricultural Research Institute, India), Sukumar Taria (Division Of Plant Physiology Icar-Indian Agricultural Research Institute, India), Madan Pal Singh (Division Of Plant Physiology IcarIndian Agricultural Research Institute, India), Viswanathan Chinnusamy (Division Of Plant Physiology Icar-Indian Agricultural Research Institute, India)

Tuesday 4 July 2023 16:00

P6.16 EXPANDING OUR MOLECULAR TOOLBOX FOR CROP IMPROVEMENT AND SUSTAINABILITY THROUGH UNDERSTANDING GENE EXAPTATION DURING THE EVOLUTION OF C4 PHOTOSYNTHESIS

P6.13 GENOME WIDE HAPLOTYPE ANALYSIS FOR REPRODUCTIVE STAGE HIGH TEMPERATURE STRESS TOLERANCE IN RICE

martha.ludwig@uwa.edu.au

C4 photosynthesis evolved from the ancestral C3 photosynthetic pathway more than 60 independent times within the angiosperms. The pathway is a carbon concentrating mechanism that enables C4 plants to outcompete plants using C3 photosynthesis in hot, dry, and/or high light environments. In all known C4 syndromes, carbonic anhydrase (CA) catalyses the first step of the pathway, in the cytosol of mesophyll cells where it is expressed at high levels. We have used closely related Flaveria species that carry out C3, C3-C4, C4-like, or C4 photosynthesis to show that the evolution of the C4-associated CA (βCA3) in this genus has occurred through two gene duplication events; the loss of the region encoding the chloroplast transit peptide from the ancestral C3 orthologue; and the transposition into the βca3 gene 5’-upstream region of a transposable element (TE), which harbours the cis-elements responsible for mesophyll-specific expression. To our knowledge, these results provide the first mechanistic understanding by which the insertion of an identified TE contributed to the evolution of C4 photosynthesis in any C4 lineage. These insights into the evolution of an enzyme that catalyses a critical step in the C4 pathway has potential for informing the design of future strategies in crop improvement and sustainability under changing climate and environmental conditions.

P6.17 DOWN-REGULATION OF WHEAT

the Rca1 and Rca2 gene expression at both transcript and protein levels.

P6.18 THE COST OF PHOTOPROTECTION TO PHOTOSYNTHESIS IN THE REALWORLD

Tuesday 4 July 2023 16:30

Liana G. Acevedo-Siaca (Michigan State University, East Lansing), Atsuko Kanazawa (Michigan State University, East Lansing), David M. Kramer (Michigan State University, East Lansing)

aceved53@msu.edu

RUBISCO

ACTIVASE ISOFORMS EXPRESSION BY VIRUS-INDUCED GENE SILENCING

Tuesday 4 July 2023 16:15

Alejandro Perdomo Lopez (University of Central Lancashire, United Kingdom), Joanna Scales (Rothamsted Research, United Kingdom), Wing-Sham Lee (Rothamsted Research, United Kingdom), Kostya Kanyuka (NIAB, United Kingdom), Elizabete Carmo-Silva (Lancaster University, United Kingdom) aperdomolopez@uclan.ac.uk

Rubisco activase (Rca) is a catalytic chaperone that remodels the conformation of Rubisco by removing inhibitors from its active sites and restoring its catalytic competence. In wheat, Rca is composed of a longer 46-kDa α-isoform and two shorter 41-42-kDa β-isoforms. These are encoded by TaRca1 and TaRca2 genes. TaRca1 produces a single transcript from which a short 1β-isoform is expressed, whereas two alternative transcripts are generated from TaRca2 directing expression of either a long 2α-isoform or a short 2β-isoform, which is similar but not identical to 1β. In this study, the regulation of the genes encoding the different TaRca isoforms was characterised using virus-induced gene silencing (VIGS). Three VIGS constructs were generated to silence the different TaRca transcripts. The abundance of the transcripts and the respective TaRca protein isoforms was then evaluated in the VIGS-treated and control plants. Remarkably, plants treated with the construct specifically targeting TaRca1 efficiently decreased expression not only of TaRca1 but also of the two alternative TaRca2 transcripts. Whereas specific targeting of the TaRca2 transcript encoding a long isoform 2α resulted in silencing of both TaRca2 alternative transcripts. The reduced abundance of the corresponding different Rca protein isoforms was also observed. These findings indicate co-regulation of

Plants experience constantly changing conditions within agricultural and natural ecosystems, however, most of our understanding of photosynthesis is within the context of steady-state conditions. We present a new chlorophyll fluorescence assay and an experimental approach to establish a global, open science network to disentangle the relationships among photosynthetic performance, photoprotection, and environmental factors under both field and controlled conditions. Specifically, we aim to test the predicted effects of transiently increased light on the quantum yield of PSII (ΦPSII), linear electron flow (LEF), non-photochemical quenching (NPQ), qE (fast-acting component of NPQ), proton motive force (pmf), and the redox states of QA and P700. Our preliminary data shows that limitations by NPQ and photochemistry are highly dependent upon leaf temperature, light intensity, and species. The ongoing project will expand these studies to a broad range of plants in diverse ecosystems and conditions to identify species in which a faster NPQ relaxation may be favorable to photochemistry and productivity, or when other limitations predominate.

P6.19 THE ABILITY OF THE MARINE ALGA ULVA LACTUCA (CHLORPHYTA) TO ABSORB AND DEGRADE HYDROCARBONS FROM FUEL

Tuesday 4 July 2023 16:45

Alberto Gonzalez (Universidad de Santiago de Chile, Chile), Stephanie Romero (Universidad de Santiago, Chile), Hector Osorio (Universidad de Santiago Chile, Chile)

alberto.gonzalezfi@usach.cl

The green marine macroalga Ulva lactuca has been found surviving in fuel contaminated coast sites in central Chile near oil refineries and petrochemical industries. At those sites there is an alarming health risk for the local communities. As this species of marine alga has an interesting tolerance to contamination by hydrocarbons our group studied the mechanisms of tolerance and accumulation of polycyclic aromatic hydrocarbons (PAHs), such as anthracene and benzopyrene, very stable molecules found in petroleum oil and also derived from industrial activities and that are classified as carcinogenic for humans, surprisingly the alga tolerated 5 µM of each PAH cultivated in vitro, and it was able to absorb them into its tissue and to degrade anthracene completely after 48 h and benzopyrene after 72 h. A degradation mechanism was proposed after a transcriptomic analysis which revealed the expression of monooxygenases, dioxygenases and other degradative enzymes, and using GC-MS several degradation metabolites were revealed which could possibly feed the mitochondrion

Martha Ludwig (University of Western Australia, Australia), Christopher J Baros (University of Western Australia, Australia), Montserrat Saladié (University of Western Australia, Australia)

for energy production. Surprisingly, in the transcriptome were found enzymes with high similitude to alkane monooxygenase, aldehyde dehydrogenase and alcohol dehydrogenase which could transform the linear hydrocarbons from diesel fuel into lipids. Our laboratory is currently studying the tolerance of this marine alga to diesel in vitro, as well as the degradation of linear hydrocarbons, our recent findings show tolerance to 2.5 % of diesel and absorption of 64 % after 48 h, also the increase in transcripts of the degradative enzymes. Financed by DICYT 022343GF and Fondecyt Iniciacion 11180189.

POSTER SESSION

Wednesday 5 July 2023 17:15-19:15

P6.20 EXPLORING THE MICROBIOME STRUCTURE OF WHOLE TALL FESCUE PLANT UNDER SALT STRESS CONDITIONS AND IDENTIFYING THE POTENTIAL FUNCTIONAL BACTERIA

Wednesday 5 July 2023

POSTER SESSION

Jianhua Zhang (Hong Kong Baptist University, Hong Kong), Tianqi Zhu (Northwest A F University, China),

Liang Zhang (Northwest A F University, China),

Zizheng Yan (Northwest A F University, China),

Bowen Liu (Northwest A F University, China),

Youyue Li (City University of Hong Kong, Hong Kong),

Xiangkai You (Shanghai Jiao Tong University, China),

Mo-xian Chen (Nanjing Forestry University, China),

Tieyuan Liu (Northwest A F University, China),

Yuefei Xu (Northwest A F University, China)

jzhang@hkbu.edu.hk

Tall fescue (Festuca arundinacea Schreb.) is a cool-season perennial grass and has excellent adaptability to salt stress. Plant microbiome may enhance its growth and salt tolerance. Here we employed 16S rRNA amplicon and internal transcribed spacer (ITS) sequencing to determine microbiome composition and abundance in different tall fescue compartments under salt stress. The above and below-ground compartments showed distinct and overlapping microbial communities. Proteobacteria was the dominant bacterial phyla in all compartments. Actinobacteria, Firmicutes, and Bacteroidetes were dominated in the above-ground compartments such as the phyllosphere, stem, and leaf sheath endosphere. Meanwhile, Actinobacteria and Bacteroidetes were also enriched in the rhizoplane and rhizosheath, whereas the root endosphere recruit abundant Chloroflexi. Fungai displayed various preference in inhabiting plant compartments. Although Ascomycota was the most dominant phylum across the whole plant, the enrichment of Basidiomycota or Gastrotricha was also observed in the phyllosphere, leaf endosphere, root endosphere, and rhizoplane. Expectedly, salt stress drives significant changes in microbiome composition in different compartments, as evidenced by the enrichment of Proteobacteria and Ascomycota, and the depletion of Bacteroidetes, Actinobacteria, Gastrotricha, and Basidiomycota. Interestingly, the abundance and diversity of bacteria varied more significantly than that of fungi in response to salt stress. Predicted functional analysis suggested that the microbes in above-ground compartments were mainly involved in streptomycin biosynthesis and glutathione metabolism, while the

microbes in below-ground compartments were mainly involved in peptidoglycan biosynthesis and lipoic acid metabolism under salt stress. The enriched Halomonas displayed an obvious promotion effect on seed germination, seedling growth, and salt tolerance.

P6.21 STORING CARBON IN LEAF LIPID SINKS REDUCES FEEDBACK INHIBITION OF LOLIUM PERENNE PHOTOSYNTHESIS AND INCREASES PASTURE ENERGY DENSITY IN THE FIELD

Wednesday 5 July 2023 POSTER SESSION

Zac Beechey-Gradwell (AgResearch, New Zealand), Luke Cooney (AgResearch, New Zealand), Somrutai Winichayakul (AgResearch, New Zealand), Mitchell Andrews (Lincoln University, New Zealand), Nick Roberts (AgResearch, New Zealand) zacbeechey@gmail.com

Plant-derived oils are an economically valuable, energy-dense carbon sink in plants, containing ~38 kJ g–1. Many studies report large increases in leaf oil content but most also report plant growth penalties associated with oil accumulation. Modifying two genes involved in lipid biosynthesis and storage [cysteine oleosin (CO) and diacylglycerol O-acyltransferase (DGAT)] resulted in the accumulation of stable lipid droplets in perennial ryegrass leaves. An unexpected secondary effect of DGAT+CO expression in perennial ryegrass was increased photosynthesis and shoot growth. To evaluate the relationship between foliar lipid accumulation and photosynthesis, we examined fatty acids (FA), water-soluble carbohydrates (WSC), relative growth rates, gas exchange parameters and leaf nitrogen for multiple DGAT+CO perennial ryegrass lines varying in transgene accumulation. DGAT+CO accumulation increased FA at the expense of leaf WSC and for those lines with a significant reduction in WSC, we also observed an increase in photosynthesis delivered through increased stomatal and mesophyll conductance, and photosynthetic electron transport. We speculate that by behaving as stable micro-sinks for carbon, COencapsulated lipid droplet accumulation can reduce feedback inhibition of photosynthesis and drive greater carbon capture. Increased foliar lipids and plant biomass could elevate energy yields from perennial ryegrass-based pastures but there are few reports of high lipid pasture plant performance under realistic growing conditions. Our thorough analysis of DGAT+CO trait translation from spaced pots indoors to field canopies showed that the benefits of enhanced FA and digestible energy content translate to DGAT+CO PR canopies grown in the field.

Wednesday 5 July 2023 POSTER SESSION

P6.22 INTROGRESSION OFE. ARUNDINACEUSANDSACCHARUM SPONTANEUMFOR THE DEVELOPMENT OF ENERGY CANE WITH HIGH BIOMASS, MULTI-RATOONABILITY AND STRESSTOLERANT VARIETIES.

Mintu Ram Meena (ICAR-Sugarcane Breeding Institute, India), P Govindaraj (ICAR-Sugarcane Breeding Institute, India), Arun Kumar R. (ICAR-Sugarcane Breeding Institute, India), M L Chhabra (ICAR-Sugarcane Breeding Institute, India), Hemaprabha G (ICAR-Sugarcane Breeding Institute India, India)

meena.mintu7@gmail.com

A total of 18 energy canes consisting of types I and II, derived from wild species ofSaccharum andE. arundinaceouswere developed and evaluated for their high biomass, ratooning potential and other stress tolerance traits in randomized block design under rainfed conditions of sub-tropical climate along with the two popular standard varieties Co 0238 and CoS 767. The experimental mean harvestable biomass yield (fresh) under rainfed conditions was 135.43 t/ha and four energy canesviz.,SBIEC 11008 (377.42 t/ha), SBIEC 11002 (232.94 t/ha), SBIEC 11004 (211.14 t/ha), SBIEC 11006 (183.54 t/ha) had superior to best standard Co 0238 (129.24 t/ha). The mean dry biomass yield in the trial recorded was 79.74 t/ha and five energy canesviz.,SBIEC 11008 (195.3 t/ha), SBIEC 11004 (149.31 t/ha), SBIEC 11005(142.39 t/ha) SBIEC 11006(130.16t/ha), and SBIEC 11001 (101.68 t/ha) were superior to best standard Co 0238 (88.98 t/ha), representing their better potential for cogeneration unit to generate more electricity. Estimated energy form Co-varieties had a range of 400-500 GJ/ha/year as compared to energy canes which had ranged from 700-1300 GJ/ha/year. Energy utilization efficiency of energy canes were higher than the cultivated varieties. Energy canes SBIEC 11008 (1.99), SBIEC 11002 (1.27), SBIEC 11006 (1.22), SBIEC 11004 (1.19), and SBIEC 11005 (1.17) had higher energy utilization than best standard check variety Co 0238 (0.77). The energy canes SBI-EC 13001 (28.12%), SBI-EC 11008 (27.49%), SBI-EC 14006 (25.09%), SBI-EC 11004 (24.66%) and SBI-EC 11001 (24%) had more fibre content than commercial canes.

P6.23 GENETIC DIVERSITY ASSESSMENT THROUGH GENOTYPING OF ADZUKI BEAN GENETIC RESOURCES FROM KOREA, CHINA AND JAPAN

Wednesday 5 July 2023

POSTER SESSION

Hyemyeong Yoon (National Institute of Agricultural Sciences, Korea (South)), Kebede Taye Desta (National Institute of Agricultural Sciences, Korea (South)), Yu-Mi Choi (National Institute of Agricultural Sciences, Korea (South)), Young-Ah Jeon (National Institute of Agricultural Sciences, Korea (South)), Myoung-Jae Shin (National Institute of Agricultural Sciences, Korea (South)), Joungyun Yi (National Institute of Agricultural Sciences, Korea (South)), Xiaohan Wang (National Institute of Agricultural Sciences, Korea (South))

mmihm@korea.kr

Adzuki bean (Vigna angularisvar.angularis) is one of the most widely cultivated legumes in East Asian countries. However, because cultivated varieties are limited, it is necessary to increase diversity by discovering new genetic resources. To assess the genetic diversity, genotyping-by-sequencing (GBS) was performed on 384 adzuki bean accessions collected from Korea, China and Japan in this study. The accessions were characterised using 9,808 SNPs with a minor allele frequency (MAF) of above 0.05 and missing data of below 0.3, and the Guanine-Cytosine (GC) content was 47.35% from a percent of

mapped reads of 97.67%. The polymorphism information content (PIC) of the SNPs was 0.26 on average, and one-third of them have PIC values over 0.33, indicating that they are highly informative. In all sites, the Heterozygosity(H) was between 0.095 and 0.500. PCA analysis revealed that Chinese accessions formed a distinct group from other accessions, but Korean and Japanese accessions were not clearly distinguished. The population structure was also divided into two clusters (K=2), but each subpopulation was not divided according to origin. Even though only the variants of adzuki bean accessions were studied, this demonstrates that the genetic resources of adzuki bean are genetically diverse. Overall, our findings will help to increase the availability of biodiversity for breeding research and improve our understanding of adzuki bean genetics.

P6.24 INTROGRESSION OFE. ARUNDINACEUSANDSACCHARUM SPONTANEUMFOR THE DEVELOPMENT OF ENERGY CANE WITH HIGH BIOMASS, MULTI-RATOONABILITY AND STRESSTOLERANT VARIETIES

Wednesday 5 July 2023 POSTER SESSION

Mintu Ram Meena (ICAR-Sugarcane Breeding Institute, India), Govindaraj P (ICAR - Sugarcane Breeding Institute, India), Govindaraj P. (ICAR - Sugarcane Breeding Institute, India), R. Arun Kumar (ICAR - Sugarcane Breeding Institute, India), M L Chhabra (ICAR-Sugarcane Breeding Institute, India), G. Hemaprabha (ICAR-Sugarcane Breeding Institute, India)

meena.mintu7@gmail.com

A total of 18 energy canes consisting of types I and II, derived from wild species ofSaccharum andE. arundinaceouswere developed and evaluated for their high biomass, ratooning potential and other stress tolerance traits in randomized block design under rainfed conditions of sub-tropical climate along with the two popular standard varieties Co 0238 and CoS 767. The experimental mean harvestable biomass yield (fresh) under rainfed conditions was 135.43 t/ha and four energy canesviz.,SBIEC 11008 (377.42 t/ha), SBIEC 11002 (232.94 t/ha), SBIEC 11004 (211.14 t/ha), SBIEC 11006 (183.54 t/ha) had superior to best standard Co 0238 (129.24 t/ha). The mean dry biomass yield in the trial recorded was 79.74 t/ha and five energy canesviz.,SBIEC 11008 (195.3 t/ha), SBIEC 11004 (149.31 t/ha), SBIEC 11005(142.39 t/ha) SBIEC 11006(130.16t/ha), and SBIEC 11001 (101.68 t/ha) were superior to best standard Co 0238 (88.98 t/ha), representing their better potential for cogeneration unit to generate more electricity. Estimated energy form Co-varieties had a range of 400-500 GJ/ha/year as compared to energy canes which had ranged from 700-1300 GJ/ha/year. Energy utilization efficiency of energy canes were higher than the cultivated varieties. Energy canes SBIEC 11008 (1.99), SBIEC 11002 (1.27), SBIEC 11006 (1.22), SBIEC 11004 (1.19), and SBIEC 11005 (1.17) had higher energy utilization than best standard check variety Co 0238 (0.77). The energy canes SBI-EC 13001 (28.12%), SBI-EC 11008 (27.49%), SBI-EC 14006 (25.09%), SBI-EC 11004 (24.66%) and SBI-EC 11001 (24%) had more fibre content than commercial canes.

P6.25 WHERE DOES YOUR FOOD REALLY COME FROM? A STUDY OF TOMATOES’ ORIGIN

Wednesday 5 July 2023 POSTER SESSION

Miranda Burke (Lancaster, United Kingdom), Martin McAinsh (Lancaster University, United Kingdom), Mike Roberts (Lancaster University, United Kingdom), Francis L Martin (Biocel Ltd, United Kingdom)

miranda.burke.2014@outlook.com

An alarming 10-30% of all food sold is estimated to be fraudulent. Food fraud causes irreparable damage to an already vulnerable global food system and negatively effects every stakeholder. Tomatoes are a culturally important fruit that provide nutrition to a global market and represent the livelihoods of many communities. The fruit label provides the origin, but the fraudulent mislabelling misrepresents legitimate, for fraudulent production, at the detriment of reliant grower communities. Existing commercial methods for detecting fraudulent food are often slow, destructive, and expensive. A non-destructive, high-throughput and cheap technology must become readily available to detect origin fraud for the infiltration and prevention of food criminals. This study investigates the use of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy as a rapid, quantitative method for detecting biochemical differences between origins from the surface tissue of tomatoes. Fruit spectra from three UK, and one Netherlands’ locations were analysed using chemometric multivariate analysis of the fingerprint region (400 cm-1 to 1500 cm-1). Distinct chemical peaks were detected which represent biomarkers associated with growing locality and conditions. Machine learning modelling shows high accuracy in categorising different origins. ATR-FTIR provides a low-cost method for in vivo detection of biochemical differences and biomarkers of origin.

P6.26 FUNCTIONAL ANALYSIS OF HISTONE DEACETYLASE 19 AND ITS ROLE IN BRACHYPODIUM STRESS ADAPTATION

Wednesday 5 July 2023 POSTER SESSION

Brittany M. Verrico (University of Vermont, United States), Jill C. Preston (University of Vermont, United States)

Brittany.Verrico@uvm.edu

Histone deacetylases (HDAs) modify chromatin to reduce transcription at specific loci and play unique roles in plant reactions to environmental stress. For example, in the dicot Arabidopsis thaliana,HDA19regulates flowering and has antagonistic functions in conferring tolerance to different abiotic stressors, namely a negative and positive effect on drought and cold tolerance, respectively. In a previous study, we found that transcription of HDA19 orthologs across temperate Pooideae grasses gradually increases with a prolonged period of above freezing cold. This process of ‘vernalization’ provides floral competency during the winter to ensure rapid spring flowering, as well as the signal for cold acclimatization that precedes freezing tolerance. We generated Brachypodium distachyon Bd21-3 (Pooideae) CRISPR lines to test the hypothesis that PooideaeHDA19acts as a promoter of flowering in the vernalization pathway and confers tolerance to low temperatures and drought stress. Comparison ofhda19mutants to wild type Bd21-3 plants under ambient, drought, and cold conditions suggests thatBdHDA19does indeed function in the control of growth, flowering time, and stress tolerance. We discuss these results in the context of a possible tradeoff between growth and resilience and their relationship to what we know aboutHDA19functioning in A. thaliana.

P7 - ENGINEERING EARTH'S CARBON CYCLE USING PLANTS AND THEIR ENVIRONMENTS

P7.1 UNDERSTANDING AND ENHANCING ROOTS CONTRIBUTIONS TO SOIL CARBON

Thursday 6 July 2023 09:00

Hanna J Poffenbarger (University of Kentucky, United States), Travis Banet (University of Kentucky, United States), Lucas P Canisares (University of Kentucky, United States), Angelica Jaconi (University of Kentucky, United States), David McNear (University of Kentucky, United States), Brian Rinehart (University of Kentucky, United States) hanna.poffenbarger@uky.edu

Root inputs to the soil are often lower than aboveground inputs, yet several studies have reported that most of the organic matter in soil is derived from roots rather than shoots. We synthesized literature on root and aboveground inputs to the soil by major crops and reviewed how belowground allocation has changed due to breeding. We found that root:shoot ratios are 0.2 to 0.4 depending on the crop, and that breeding for yield has largely not altered this ratio. One factor that may explain the disproportionate contribution of roots to soil organic matter is the greater biochemical recalcitrance of root tissues than shoot tissues. To understand the effect of biochemical recalcitrance on the persistence of root-derived organic matter, we monitored the decomposition of root litters from seven species ranging in suberin content and other compounds in two soils (sandy loam and silt loam). This study was conducted under controlled moisture and temperature conditions in the laboratory. We found that cumulative respired C was negatively related to the natural log of suberin biomarkers for both soil types. We are also determining how root chemical composition affects the amount of root carbon transferred to labile and stable organic matter fractions. This research may help to explain the disproportionate contribution of roots to soil organic matter and identify chemical root traits that promote the formation of stable soil organic matter.

SEQUESTRATION?

Thursday 6 July 2023 09:30

liz.baggs@ed.ac.uk

Increasing soil organic matter (SOM) is a practical option towards achieving targets for net zero emissions, and confers a range of benefits for soil health and ecosystem services. Plant-derived C from living roots shapes the soil microbial community and is key in altering the balance between net C accrual and release from SOM. Our research in barley and maize has demonstrated significant genotypic variation in the ability of crop lines to promote release of C from SOM. We have shown this to be related to root physiological traits associated with rhizodeposition. For example, we show root length, root diameter and root-derived C mineralisation to be strong predictors of SOM-C mineralisation, and have identified candidate genes in maize and barley associated with enhanced SOM mineralisation. Whilst this research is guiding selection of lines best suited to source nutrients from SOM, this approach can also identify root traits associated with net C accrual. It is promising to target genes associated with root exudate release to mediate balances of C-stabilisation and loss in the rhizosphere. We discuss our findings in the context of sustainable production in systems managed to enhance SOM, and the opportunity to capitalise on root trait influences to inform selection of crop lines as a management option to enhance SOM-C.

P7.3

GENETICS TO FIGHT THE CIMATE CRISIS

Thursday 6 July 2023 10:00

Wolfgang Busch (Salk Institute, United States)

wbusch@salk.edu

Climate change will soon profoundly and negatively affect the vast majority of our planet’s biota, including most human beings. Despite the importance and urgency of addressing this problem, we still lack technologies to globally address the root cause of climate change –increased levels of CO2 in the atmosphere. Since plants are central agents in the earth’s carbon cycle, fixing atmospheric carbon that then mostly gets released when they decompose, engineering plant traits

P7.2 DO RELATIONSHIPS BETWEEN ROOT TRAITS AND SOIL C DYNAMICS HOLD THE KEY TO ENHANCING SOIL C

Liz Baggs (University of Edinburgh, United Kingdom), Jill Cairns (CIMMYT, Zimbabwe), Blessing Mhlanga (CIMMYT, Zimbabwe), Christian Thierfelder (CIMMYT, Zimbabwe), Tim Daniell (University of Sheffield, United Kingdom), Manje Gowda (CIMMYT, Kenya), Eric Paterson (The James Hutton Institute, United Kingdom)

USING PLANT

ORGANISED BY: CHRIS TOPP (DONALD DANFORTH PLANT SCIENCE CENTER), WOLFGANG BUSCH (SALK INSTITUTE FOR BIOLOGICAL STUDIES)

that affect the decomposition rate of plant derived carbon molecules can potentially lead to a large and globally significant drawdown of atmospheric CO2 . In particular, root systems and the rhizosphere are of interest for such approaches as soils are enormous carbon sinks. Since plants first colonized the earth’s land surfaces, their carbon depositions have built up three times more carbon in the soil than is contained in the atmosphere. Specific root traits are clearly important contributors to the accumulation and permanence of carbon in the soil. Two of these traits are root depth and the levels of refractory carbon compounds in root tissues. We are using an integrated approach utilizing genetics, cell & molecular biology, biochemistry, computer science, and functional genomics approaches in the model plant Arabidopsis thaliana and several crop species to identify genetic and molecular mechanisms that regulate these traits and attempt to utilize this knowledge to enhance traits relating to carbon accumulation and permanence in soils.

P7.5 USING PLANT-MICROBE-MINERAL INTERACTIONS TO MANAGE CARBON CYCLING

Thursday 6 July 2023 11:00

Kirsten Hofmockel (Pacific Northwest National Laboratory, United States), Katherine Naasko (Pacific Northwest National Laboratory, United States), Sneha Couvillion (Pacific Northwest National Laboratory, United States), Janet Jansson (Pacific Northwest National Laboratory, United States)

kirsten.hofmockel@pnnl.gov

The rhizosphere microbiome is critical to plant performance and soil biogeochemical cycling with important feedbacks to the global carbon cycle, including plant growth, stress tolerance and carbon metabolism. Understanding the functional components of the rhizosphere microbiome is essential for sustainable crop production and climate mitigation. Our research aims to determine how the rhizosphere of perennial plants influences microbial structure and function throughout the soil profile and the implications of these plant-microbe-mineral interactions on carbon cycling. We conducted our research in a marginal soil, using a multi-omics approach to determine how plant-microbemineral interactions influence carbon cycling. Rhizosphere effects on community membership were more pronounced than soil depth, yet we found significant shifts in metabolic signatures throughout the soil profile. On average, the surface soil had significantly higher levels of trehalose and several sugar alcohols known to be produced in response to water, heat, and salt stress. Differences in soil chemistry and mineralogy between the surface and deep soil influenced the fate of plant and microbial metabolites and residues. The deep calcareous soil horizon contained significantly higher levels of organic acids. Soil calcium concentrations were positively correlated with benzoic acid and lactic acid concentrations, suggesting enhanced dissolution of inorganic C. Together these results illustrate the importance of rhizosphere-microbe-mineral interactions in generating and retaining organic and inorganic forms of C throughout the soil profile, and provide important considerations for managing the rhizosphere to support sustainable carbon retention.

P7.6 CO-OPTIMIZING COVER AND CASH CROP ROOT AND RHIZOSPHERE TRAITS FOR PRODUCTIVE AND SUSTAINABLE CROPPING SYSTEMS USING PHENOMICS AND RATIONAL DESIGN

Thursday 6 July 2023 11:45

Chris Topp (Danforth Plant Science Center, United States), Kong Wong (Danforth Plant Science Center, United States), Marcus Griffiths (Danforth Plant Science Center, United States), George Bagnall (Danforth Plant Science Center, United States), Alex Liu (Danforth Plant Science Center, United States), Michelle Cho (Danforth Plant Science Center, United States), Keith Duncan (Danforth Plant Science Center, United States)

CTopp@danforthcenter.org

Widespread use of cover crops presents an immediate large-scale opportunity to increase soil carbon and reduce the negative effects of unsustainable agricultural inputs such as synthetic nitrogen. Yet numerous extant and potential cover crop species have not been intensively bred for traits that influence key ecosystem services and compatibility with cash crops. Likewise, most cash crops are optimized for conventional agricultural practices that we know are unsustainable and need a rational re-design, most notably in their root and rhizosphere traits. We will discuss key genes and genetic variation our root phenomics research program has identified that control quantitative variation in maize and cover crop root system traits and that can provide more efficient nitrogen uptake in the field. We will also present findings from our above- and belowground phenomics efforts to dozens of cover crop species and mixtures that highlight the enormous amount of genetic and phenotypic variation that can be leveraged in service of more sustainable and carbon negative cropping systems.

P7.7 FOREST CARBON SEQUESTRATIONA MATTER OF DYNAMICS

Thursday 6 July 2023 14:30

Thomas A.M. Pugh (Lund University, Sweden), Nezha Acil (University of Birmingham, United Kingdom), Julen Astigarraga (University of Alcala, Spain), Annemarie Eckes-Shephard (Lund University, Sweden), Adriane Esquivel-Muelbert (University of Birmingham, United Kingdom), Daijun Liu (University of Vienna, Austria), Stefan Olin (Lund University, Sweden), Phillip Papastefanou (Max Planck Institute for Biogeochemistry, Germany)

thomas.pugh@nateko.lu.se

Forests around the world take up and store around 20-30% of humanity’s carbon emissions every year, principally in biomass. Two main drivers account for most of this effect: increases in forest productivity due to rising atmospheric carbon dioxide concentrations and the shifting of forest age towards stands with younger more vigorous trees. Their proven ability to take up carbon means that forests are often discussed as an important nature-based solution for climate change mitigation - effectively turning from centuries of inadvertent geoengineering of the climate through deforestation and

management, to a future where forests are managed purposefully to maintain or increase carbon uptake. But there is increasing evidence that stress from climate change is starting to have substantial effects on forests, increasing tree mortality rates in many regions. Increases in tree mortality stand to both reduce the existing sink and the potential gains from new planting or some management changes. It is therefore ever more important to understand how the rates of tree mortality vary around the world, how they are changing and what is likely to happen in the future. In this talk I will describe some of our latest efforts to assess tree mortality rates, identify the drivers behind them and explore the implications for the sink status of the world’s forests.

P7.8 CARBON SEQUESTRATION OR GREENHOUSE GAS EMISSION AVOIDANCE IN TROPICAL ENVIRONMENTS. INCREASING CARBON CAPTURE IN TROPICAL ENVIRONMENTS

Thursday 6 July 2023 15:00

Maria Fernanda Alvarez (Alliance of Bioversity International and CIAT)

hanna.poffenbarger@uky.edu

Tropical environments are critical in global carbon sequestration, and it is essential to maintain their forest areas to mitigate climate change. However, several factors, such as soil degradation due to intensive agricultural practices, and deforestation of tropical forests contribute to carbon release. To counter this, promoting agroforestry systems that sequester carbon in plant biomass and long-lasting wood products can be a promising solution. Above-ground biomass is also a good option, with some systems capable of sequestering 20 to 28 tons of carbon per hectare. Additionally, practices that maximize organic matter input into the soil are crucial for effective carbon sequestration.Furthermore, including farming systems and cultivated areas of tropical environments, where 40% of the world's food is produced, is crucial in mitigating climate change. Adapting crops to increase their carbon sequestration capacity can potentially affect up to 50% of the cultivable land worldwide. Additionally, implementing silvopastoral systems and rotation systems with sustainable practices can improve carbon sequestration in cultivated lands. These measures can make a significant impact on achieving sustainability goals and mitigating climate change.

P7.9 RICE ROOT SYSTEM ARCHITECTURE TRAITS THAT ENHANCE MICROBIAL ASSOCIATIONS AND CARBON SEQUESTRATION

Thursday 6 July 2023 15:30

Maria Florencia Ercoli (Department of Plant Pathology and the Genome Center University of California Davis, United States), Ryan C Packer (Department of Plant Pathology and the Genome Center University of California Davis., United States), Alexandra Shigenaga (Department of Plant Pathology and the Genome Center University of California Davis., United States), Artur Teixeira de Araujo Junior (Department of Plant Pathology and the Genome Center University of California Davis., United States), Katerina Estera-Molina (Innovative Genomics Institute University of California Berkeley, United States), Christina Fossum (Innovative Genomics Institute University of California Berkeley, United States), Jack Kim (Innovative Genomics Institute University of California Berkeley, United States), Ling-Dong Shi (Innovative Genomics Institute University of California Berkeley, United States), Peter G Lynagh (Department of Plant Pathology and the Genome Center University of California Davis., United States), Sanghwa Lee (Salk Institute for Biological Studies Plant Molecular and Cellular Biology Laboratory California, United States), Wolfgang Busch (Salk Institute for Biological Studies Plant Molecular and Cellular Biology Laboratory California, United States), Jill Banfield (Innovative Genomics Institute University of California Berkeley, United States), Jennifer Pett-Ridge (Innovative Genomics Institute University of California Berkeley, United States), Pamela C Ronald (Department of Plant Pathology and the Genome Center University of California Davis., United States) mercoli@ucdavis.edu

Rice paddy cultivation produces up to 12% of anthropogenic methane emissions, therefore, new approaches for capturing atmospheric carbon are needed. Modifying the root system architecture (RSA) and exudate composition provides an exciting opportunity for plant breeding with the goal of producing crop varieties optimized for enhanced soil carbon sequestration and reduced methane emission. In this study, we show that OsPSY1, a member of the PLANT PEPTIDE SULFATED IN TYROSINE (OsPSYs) peptide family, regulates RSA in rice. OsPSY1 ectopic expression (Ubi:OsPSY1) increased root length in rice seedlings and rice plants grown in agricultural soil. RNA-seq analysis of peptide-treated rice roots indicated that OsPSY1 controls the expression of genes involved in the biosynthesis of secondary metabolite biosynthesis, such as phenylpropanoids. Because these metabolites are known to be released into the rhizosphere, where they are involved in plant/microbe interactions, exudate composition was tested in plants with modified levels of PSYs. We also designed a greenhouse experiment in which we grew plants in agricultural soil to study rhizosphere associations. At different time points along the plant life cycle, we coupled the collection of rhizosphere samples to methane fluxes measurements. We observed a significant reduction of methane flux in the Ubi:OsPSY1 plants compared to the control at heading time. Analysis of rhizosphere samples will help us understand the effects of modifying root system architecture on microbial associations and their impact on carbon cycling and greenhouse emissions.

P7.4 USING PLANT GENETICS TO FIGHT THE CIMATE CRISIS

Thursday 6 July 2023

16:30-17:00

Jennifer Pett-Ridge (Lawrence Livermore National Laboratory)

wbusch@salk.edu

Climate change will soon profoundly and negatively affect the vast majority of our planet’s biota, including most human beings. Despite the importance and urgency of addressing this problem, we still lack technologies to globally address the root cause of climate change –increased levels of CO2 in the atmosphere. Since plants are central agents in the earth’s carbon cycle, fixing atmospheric carbon that then mostly gets released when they decompose, engineering plant traits that affect the decomposition rate of plant derived carbon molecules can potentially lead to a large and globally significant drawdown of atmospheric CO2. In particular, root systems and the rhizosphere are of interest for such approaches as soils are enormous carbon sinks. Since plants first colonized the earth’s land surfaces, their carbon depositions have built up three times more carbon in the soil than is contained in the atmosphere. Specific root traits are clearly important contributors to the accumulation and permanence of carbon in the soil. Two of these traits are root depth and the levels of refractory carbon compounds in root tissues. We are using an integrated approach utilizing genetics, cell & molecular biology, biochemistry, computer science, and functional genomics approaches in the model plant Arabidopsis thaliana and several crop species to identify genetic and molecular mechanisms that regulate these traits and attempt to utilize this knowledge to enhance traits relating to carbon accumulation and permanence in soils.

P7.11 RHIZOSPHERE ON A CHIP: NEW TECHNIQUES FOR STUDYING THE IMPACT OF PLANT ROOTS ON SOIL BIOLOGICAL AND CHEMICAL ACTIVITY

Thursday 6 July 2023 17:30

Daniel Patko (University of the Basque Country UPVEHU, Spain), Yangminghao Liu (The James Hutton Institute, United Kingdom), Ilonka C Engelhardt (University of Tübinegn, Germany), Lourdes Basabe-Desmonts (University of the Basque Country UPVEHU, Spain), Fernando Benito-Lopez (University of the Basque Country UPVEHU, Spain), Lionel X Dupuy (Neiker, Spain)

patko.daniel@gmail.com

The growing world population is causing unprecedented pressure on land use. Knowledge of how plant roots affect the biology and chemistry of soils is crucial to preserving soil quality and maintaining crop yield. However, reproducing and studying plant-soil systems in laboratories is challenging, and this limits our understanding of how they function. Here, we present tools recently developed for the live screening of rhizosphere processes. We combined new materials with soil like physical matrix, environmental control, biochemical probes, live quantitative imaging and microfluidic systems. We applied our systems to track the movement and growth of microorganisms, to identify the sites where exudates are deposited in soil and to characterise how root exudation rate varies along the root. Results show the development of model systems to study the rhizosphere in controlled conditions are within reach and these could greatly enhance our understanding of root-soil dynamics.

Image courtesy of Helena Arents

P8 - PEPG: PLANT PHYSIOLOGICAL RESPONSES ACROSS SCALES

ORGANISED BY: AMANDA CAVANAGH (UNIVERSITY OF ESSEX), GILES JOHNSON (UNIVERSITY OF MANCHESTER)

P8.1 LEAVING THE WATER, COMING BACK IN: COEVOLUTIONARY TRENDS IN THE CO2 ASSIMILATION OF LAND PLANTS

Wednesday 5 July 2023 09:00

Jeroni Galmés (Universitat de les Illes Balears, Spain), Pere Aguiló-Nicolau (Universitat de les Illes Balears, Spain), Sebastià Capó-Bauçà (Universitat de les Illes Balears, Spain), Joan Pons (IMEDEA, Spain), Jose Antonio Jurado-Rivera (Universitat de les Illes Balears, Spain), Concepción Iñiguez (Universitat de les Illes Balears, Spain)

jeroni.galmes@uib.cat

The transition from aquatic to land-adapted photosynthesis in the Ordovician was a remarkable achievement in the evolution of plants. The terrestrialization of photosynthesis required the gradual acquisition of anatomical, physiological and biochemical traits to enable efficient CO2 capture and fixation during the colonisation of the new environments, subjected to novel and more variable stressors. Among these traits, increasing stomatal and leaf vein densities during the Cretaceous enabled seed plants to boost their photosynthetic capacity, and productivity, as compared to older Embryophyta groups. The enhanced capacity to assimilate CO2 of angiosperms also required anatomical changes to facilitate the internal leaf transport of CO2 towards the sites of carboxylation, mainly a thinner cell wall and a more efficient distribution of chloroplasts. While the evolution of stomata and leaf mesophyll during the radiation of land plants have been previously investigated, no information is available on how Rubisco traits co-evolved with the CO2 diffusion components of photosynthesis. The reverse path, i.e., the re-colonisation of aquatic environments by a selected group of angiosperms, holds even more unknowns, including not only those regarding Rubisco’s performance, but also those related with the diffusive components of photosynthesis.

In the present talk, we will decipher the role of Rubisco in maximizing photosynthesis during the radiation of land plants and also during the re-colonisation of marine habitats. We will discover how carbon acquisition and assimilation mechanisms adapted to the new environments by tight coevolutionary convergence between Rubisco function and CO2-delivery mechanisms to the leaf mesophyll.

P8.2 IDENTIFYING MASTERREGULATORS OF THERMOTOLERANCE AND THE HEAT STRESS RESPONSE IN CLIMATE-ADAPTED BREAD WHEAT

LANDRACES USING A NETWORK APPROACH

Wednesday 5 July 2023 09:30

Liam J Barratt (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom), Zhesi He (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom), Alison Fellgett (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom), Lihong Wang (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom),

Sara Franco Ortega (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom),

Simon McQueen Mason (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom),

Ian Bancroft (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom), Andrea L Harper (Centre for Novel Agricultural Products (CNAP) University of York, United Kingdom)

lb1309@york.ac.uk

Bread wheat (Triticum aestivumL.) is a crop relied on by billions of people around the world as a major source of both income and calories. The changing climate, however, poses a threat to the livelihood of these people, as wheat crops are extremely vulnerable to damage by heat and drought stresses. Here we present the YoGI wheat landrace panel, comprised of 342 accessions which show remarkable variation in abiotic stress tolerance thanks to extensive genetic diversity and adaptation to vastly different climates. We quantified the abundance of 110,790 transcripts from the panel, grown under optimal conditions, and used these data to conduct weighted co-expression network analysis to identify master-regulator “hub genes” determining basal early thermotolerance. We demonstrated a significant relationship between the expression of a heat shock protein (HSP) hub gene and early thermotolerance, which appears to regulate expression of a suite of HSPs and heat shock transcription factors (Hsfs) known to have beneficial effects on thermotolerance. To investigate the response to heat stress, we also generated RNA-seq data from 15 landrace accessions before and after early heat stress exposure, from which differentially expressed genes (DEGs) were determined, and a weighted co-expression network was used to identify hub genes. We

found several hub genes which may act to downregulate seemingly superfluous genes involved in the response to other stresses, namely drought and cold, whilst another HSP hub gene appears to control the heat stress response, again via regulation of a vast suite of HSPs and Hsfs.

P8.3 RUBISCO ACTIVASE REGULATION BY LIGHT IN TOMATO

Wednesday 5 July 2023 09:45

ROS production under stress. Our findings provide a basis for new approaches to redesign photosynthesis using PTOX, to help crops face the challenges raised by the current climate change scenario.

P8.5 KFEPEPC2 ISOFORM OF THE PHOSPHOENOLPYRUVATE CARBOXYLASE (PEPC) GENE IS IMPLICATED IN NONPHOTOSYNTHETIC ACTIVITIES OF K. FEDTSCHENKOI.

Wednesday 5 July 2023 10:15

j.amaral@lancaster.ac.uk

The current demand to feed a growing population under a climate change scenario has led scientists worldwide to focus on developing strategies to improve photosynthesis for higher yielding crops. Rubisco, the most abundant protein on Earth, has been extensively studied for that purpose. In particular, its regulation by Rubisco activase (Rca) in shade-sun transitions could be more efficient and improve photosynthetic productivity in crop plants. In the light, this chaperone promotes the release of Rubisco inhibitors in an ATP-dependent manner, being regulated by the chloroplast redox status, ADP:ATP ratio, and temperature. Most plants have longer redox-sensitive α Rca isoforms and shorter redox-insensitive β isoforms. However, tomato presents only two β isoforms and the regulation of Rca in this important crop species has not been explored yet. Therefore, we aim at investigating how these two tomato Rca isoforms regulate Rubisco under changing chloroplast conditions in response to light. These studies contribute for the current knowledge on Rubisco regulation and support the development of innovative strategies to improve crop yield through photosynthesis.

P8.4 SHEDDING LIGHT ONTO THE ROLE OF THE PLASTID TERMINAL OXIDASE (PTOX) AS A SAFETY VALVE FOR PHOTOPROTECTION IN PLANTS

Wednesday 5 July 2023 10:00

Pablo I Calzadilla (The University of Manchester, United Kingdom), Junliang Song (The University of Manchester, United Kingdom), Patrick Gallois (The University of Manchester, United Kingdom), Giles Johnson (The University of Manchester, United Kingdom)

pablo.calzadilla@manchester.ac.uk

Changing climate impacts all aspects of plant physiology, photosynthesis being particularly affected. Weather extremes result in imbalances between light capture and its assimilation, leading to photoinhibition of photosynthesis, which affects plant growth and crop yields. The Plastid Terminal Oxidase (PTOX) has been suggested as a photoprotective safety valve for photosynthesis. However, a photoprotective activity has only been observed in a small number of species and its mode of activation remains elusive. Previous attempts to induce photoprotective PTOX activity in additional species have failed. Here, we show for the first time that photoprotection by PTOX can be transferred to non-extremophile species, and that can reduce photoinhibition and

Osita W Nwokeocha (Newcastle University, United Kingdom), Anne Borland (Newcastle University, United Kingdom), Maxim Kapralov (Newcastle University, United Kingdom)

o.nwokeocha2@newcastle.ac.uk

Crassulacean acid metabolism (CAM) is one of plants' three types of photosynthesis. CAM evolved from C3 via changes in protein sequence and temporal gene expression. Compared to C3 and C4 photosynthesis types, CAM shows resilient photosynthetic ability under limited water availability. A key step in CAM photosynthesis involves phosphoenolpyruvate carboxylase (PEPC), which catalyzes nocturnal carboxylation of phosphoenolpyruvate (PEP) to form oxaloacetate which is reduced to malate. PEPC is controlled transcriptionally and post-translationally. One of the two most abundant isoforms of PEPC in Kalanchoë fedtschenkoi is KfePEPC2 (Kaladp0048s0578.1), which is expressed abundantly in the dark period. CRISPR-Cas9 loss of function technique was employed to create mutants of K. fedtschenkoi with the diel expression of KfePEPC2 gene suppressed and these mutants were used to carry out physiological and biochemical characterizations to establish the physiological roles of PEPC2 in two independent lines of the mutant compared to the wildtype. Both lines of the kfepepc2 mutants retained all the attributes of CAM observed in wildtype, although down-regulation of diel transcript abundance of the rbcL gene during the middle of the daytime was observed. Furthermore, the ability of thekfepepc2 mutants to regulate stomatal opening, especially towards the end of the light period, was significantly compromised, and growth was significantly suppressed. In addition, the KfePEPC2 mutation caused a reduction in stomatal density and increased pore length. These observations indicated that the KfePEPC2 gene isoform is implicated in other important non-photosynthetic functions, which are key to physiological performance in K. fedtschenkoi. Results from this work indicate that KfePEPC2 isoform play pivotal non photosynthetic role in K. fedtschenkoi and successfully bioengineer CAM into C3 plants, KfePEPC2 gene must be functional in the bioengineered system.

P8.6 C2 PHOTOSYNTHESIS ACROSS SCALES

Wednesday 5 July 2023 11:00

Marjorie R Lundgren (Lancaster University, United Kingdom)

m.lundgren@lancaster.ac.uk

Plants have evolved extraordinary diversity in the carbon fixation pathways of photosynthesis that allow species to survive and thrive

Joana Amaral (Lancaster University, United Kingdom), Elizabete Carmo-Silva (Lancaster University, United Kingdom)

across a broad array of ecological niches on the planetary surface. While most plants use only C3 photosynthesis, this physiology is heavily affected by high rates of photorespiration under warm and arid environments. In response, some plant lineages have evolved carbon concentrating mechanisms (CCMs) to improve net carbon assimilation in these high photorespiration environments. C2 photosynthesis is one such CCM that can increase net CO2 assimilation by capturing, concentrating, and re-assimilating CO2 released by photorespiration. This talk will discuss C2 photosynthesis across scales, from the evolutionary history and biogeography of C2 plants, to their unique whole-plant growth patterns, and to specifics of their mesophyll structure, vascular patterning, and ultrastructure. In all cases, C2 plants will be compared to their close C3 and C4 relatives for context. The talk will conclude with a discussion on the potential for C2 photosynthesis engineering programmes to improve the efficiency of C3 crops.

P8.7 THE ROLE OF THE CELL WALL IN PLANT DEFENCE AGAINST ICE AND FREEZING CONDITIONS

Wednesday 5 July 2023 11:30

Phil Butlin (University of Edinburgh, United Kingdom), Karen Halliday (University of Edinburgh, United Kingdom)

phil.butlin@ed.ac.uk

Through phenotypic plasticity, plants are able to adapt their development to best suit their environment. A well characterised example of this is the shade avoidance syndrome, which is classically described as an elongation in plant architecture that helps to direct growth out of shade, thus improving light capture. The occurrence of the shade avoidance syndrome is determined by the ratio of red relative to far-red (R:FR) wavelengths of light, with low ratios in FR-rich shade environments driving elongation predominantly through inactivation of phytochrome B. Equally, it has been shown that shade avoidance can become attenuated when R:FR is extremely low, such as in deep shade, as a result of activation of phytochrome A. Here, I will present data that points to a more prominent role for phytochrome A in the regulation of shade avoidance, demonstrating that it can operate over a broader range of conditions than those attributed to ‘deep shade’ environments. I will focus on how plants determine when to initiate shade avoidance, what this means in nature and why we need to carefully consider the conditions used in experiments.

CONTROL

p.h.knight@durham.ac.uk

Many temperate plant species improve their ability to tolerate freezing conditions through the process of cold acclimation, responding with positive changes to a cool period typical of autumn weather. Numerous cellular, biochemical and transcriptional changes occur in acclimating plants responding to low positive temperatures. Alterations in lipid composition renders membranes more able to withstand very low temperatures and the accumulation of solutes in the cytoplasm reduces freeze-induced cellular dehydration. In recent years, it has become increasingly clear that in addition to these well-studied changes, the plant cell wall is modified during cold acclimation. We have observed increased abundance of cell wall extensins and changes in pectin methyl-esterification status in cold acclimating Arabidopsis thaliana. Such data indicate that the composition, and quite likely structure, of the cell wall contribute to determining the plant’s level of freezing tolerance. In support of this hypothesis, we identifiedSENSITIVE-TOFREEZING 8(SFR8); a gene influencing both cell wall composition and freezing sensitivity.sfr8mutants have greatly reduced levels of cellwall fucose and as a result, altered pectin crosslinking. Currently, we are working to understand how cell wall composition, and polymer crosslinking might influence physical and mechanical properties that could modify freezing tolerance. We are imaging ice as it forms in and around cell walls with differing compositions to examine whether the wall contributes to frost tolerance through impeding ice crystal initiation and growth and asking whether mechanical strength is associated with resilience to freezing conditions.

P8.8 RE-DEFINING CONDITIONS FOR PHYTOCHROME A ACTION UNDER SHADE.

Wednesday 5 July 2023 11:45

VULGARE) UNDER CHANGING SALINITY: NEW PLAYERS AND TARGETS FOR GENETIC IMPROVEMENT

Wednesday 5 July 2023 12:00

Ayesha S Wellawatta (The Australian National University, Australia), Josette Masle (The Australian National University, Australia)

ayesha.wellawatta@anu.edu.au

Germination is a critical phase transition in a plant life cycle.Contrary to dormancy mechanisms, the mechanisms controlling germination in non-dormant seeds remain little known. We investigated putative barley orthologs of an Arabidopsis gene family previously identified in the Masle lab as critical to the initiation and progression of germination under salinity and osmotic stress. The profound structural, compositional and germination regulation differences between the Arabidopsis and cereal/grass seeds raised the question of the relevance of those genes outside Arabidopsis, in major staple crops. To investigate the functional conservation and adaptive significance of our target genes, we engineered CRISPR-Cas9 transgenic lines edited in one or two members of the putative orthologous barley, and isolated a set of homozygous “mutants”. Some mutations and combinations of mutations delayed and slowed germination under salinity stress, but contrary to Arabidopsis, so too constitutively, under optimal environmental conditions. Their analysis showed that this was primarily controlled by the seed husk, through properties determined during development on the mother plant, some anatomical, others yet to be identified, and involved a novel transcription factor, not previously known to play a role in seeds. These results open avenues for the genetic improvement of crop performance and adaptation to climate change.

P8.9 GENETIC

OF SEED GERMINATION IN BARLEY (HORDEUM

Heather Knight (Heather Knight, United Kingdom), Irabonosi Obomighie (Durham University, United Kingdom), Nathan J Ramsay (Durham University, United Kingdom), Tim J Hawkins (Durham University, United Kingdom)

P8.11 THE PHYSIOLOGICAL AND EPIGENETIC EFFECTS OF FLUCTUATING LIGHT IN ARABIDOPSIS THALIANA

Wednesday 5 July 2023 12:15

Robyn Emmerson (University of Essex University of Birmingham, United Kingdom), Radu Zabet (University of Essex, United Kingdom), Marco Catoni (University of Birmingham, United Kingdom), Tracy Lawson (University of Essex, United Kingdom)

r.emmerson@bham.ac.uk

Natural light is highly dynamic, capable of changing within seconds. Plants must cope with these changes for their survival, and fluctuating light conditions result in a range of physiological changes, including biochemical and stomatal limitation. However relatively little is known about the impacts of fluctuating light on genome regulation. To aid our understanding of how this response may be regulated on a dynamic genome level, differences in physiology and epigenetic variation were investigated in Arabidopsis exposed to fluctuating light. Genome wide difference in DNA methylation was noted, particularly in transposable elements, and some differentially methylated regions were correlated with change in gene expression according to RNAseq data. In addition, mutant plants in the main plant DNA methyltransferase MET1 display physiological alterations in response to light, with increases in photosystem II efficiency under fluctuating light compared to the wild type. This suggests a direct role of epigenetic regulation in the response to variation in the light conditions. Our results show that the plant physiological adaptation to changes in light regimes can be at least partially under epigenetic control, suggesting that epigenetics might have a central role in controlling photosynthetic efficiency in response to environmental stimuli.

P8.12 HIGH CYCLIC ELECTRON TRANSFER VIA THE PGR5 PATHWAY IN THE ABSENCE OF PHOTOSYNTHETIC CONTROL

Wednesday 5 July 2023 12:15

Gustaf E Degen (University of Sheffield, United Kingdom),

Philip J Jackson (University of Sheffield, United Kingdom),

Matthew S Proctor (University of Sheffield, United Kingdom),

Nicholas Zoulias (University of Sheffield, United Kingdom),

Stuart A Casson (University of Sheffield, United Kingdom),

Matthew P Johnson (University of Sheffield, United Kingdom)

g.degen@sheffield.ac.uk

The light reactions of photosynthesis couple electron and proton transfers across the thylakoid membrane, generating NADPH, and proton motive force (pmf) that powers the endergonic synthesis of ATP by ATP synthase. ATP and NADPH are required for CO2 fixation into carbohydrates by the Calvin-Benson-Bassham cycle (CBBC). The dominant ΔpH component of the pmf also plays a photoprotective role in regulating photosystem II (PSII) light harvesting efficiency through non-photochemical quenching (NPQ) and photosynthetic control via electron transfer from cytochrome b6 f (cytb6 f) to photosystem I (PSI). ΔpH can be adjusted by increasing the proton influx into the thylakoid lumen via upregulation of cyclic electron transfer (CET) or decreasing

proton efflux via downregulation of ATP synthase conductivity (gH+). The interplay and relative contributions of these two elements of ΔpH control to photoprotection are not well understood. Here, we showed that an Arabidopsis (Arabidopsis thaliana) ATP synthase mutant hunger for oxygen in photosynthetic transfer reaction 2 (hope2) with 40% higher proton efflux has high CET. Double crosses of hope2 with the CET-deficient pgr5 and ndho lines revealed that PGR5-dependent CET is the major pathway contributing to higher proton influx. PGR5dependent CET allowed hope2 to maintain wild-type levels of ΔpH, CO2 fixation and NPQ, however photosynthetic control Y(ND) remained absent, and PSI was prone to photoinhibition. Intriguingly, infiltration of hope2 leaves with methyl viologen did not restore Y(ND) but did so in pgr5 to a certain extend. Therefore, high CET in the absence of ATP synthase regulation is insufficient for PSI photoprotection.

P8.13 EPIGENETIC REGULATION OF FLOWERING TIME CONTROL IN ARABIDOPSIS

Wednesday 5 July 2023 12:15

Rea L Antoniou-Kourounioti (University of Glasgow, United Kingdom), Svenja Reeck (John Innes Centre, United Kingdom), Anis Meschichi (Swedish University of Agricultural Sciences, Sweden), Jo Hepworth (Durham University, United Kingdom), Yusheng Zhao (IGDB Chinese Academy of Sciences, China), Stefanie Rosa (Swedish University of Agricultural Sciences, Sweden), Caroline Dean (John Innes Centre, United Kingdom), Martin Howard (John Innes Centre, United Kingdom)

ReaLaila.AntoniouKourounioti@glasgow.ac.uk

Many plants produce flowers in spring through the process of “vernalization”, by sensing and remembering the cold of winter. This is controlled by the gene FLOWERING LOCUS C (FLC) and its regulators in Arabidopsis thaliana. In this talk I will discuss work combining mathematical modelling and experiments to understand how plants regulate and how they satisfy this cold requirement. The epigenetic regulation of FLC is the crucial step in this process, which is controlled by genetic variation and environmental signals. The response in the autumn is most variable between different natural populations. Mathematical models have been developed in this work for the temperature sensing and epigenetic regulation of this gene which can predict its expression in field conditions and have given us a deeper understanding into the mechanisms of these processes.

P8.15 HOW AND WHY DOES VARIABLE LIGHT AFFECT GROWTH IN PHOTOTROPHS?

Wednesday 5 July 2023 12:015

Belinda C Comerford (Monash University, Australia), Dustin J Marshall (Monash University, Australia)

belinda.comerford@monash.edu

Light always varies but there is no consensus about the effects of light variation on plant growth. Crucially, for variable light to benefit growth, plants must ‘integrate’ light, such that brief exposures to light result in some photosynthesis beyond the exposure period.

While light integration has been the subject of speculation for over 80 years, formal attempts to quantify it are surprisingly rare. We conducted a meta-analysis on 164 studies to determine how light variation affects growth. We found growth in variable-light regimes was sometimes equivalent to growth in constant-light regimes, but never exceeded it. After accounting for reduced light doses in variablelight regimes, the relative benefits of variable light were remarkably strong—despite receiving 10% of the constant-light regime light, growth in variable-light regimes was only lowered by 7%. We used these results to parameterise a simple model of light integration and found that our meta-analytic results only emerge if plants integrate light over 110-milliseconds.Most light regimes experienced by plants (i.e., low frequencies) reduce growth in an absolute sense. But, the capacity for plants to integrate light over high frequencies offsets the impacts of variable light and opens the potential for significant power savings in indoor agricultural settings.

P8.16 INSIGHT ON LEAF PROTEOME UPON RECOVERY TO WARM ACCLIMATION.

Wednesday 5 July 2023 12:15

Norazreen Abd Rahman (University of Manchester, United Kingdom), Giles Johnson (University of Manchester, United Kingdom)

norazreen.bintiabdrahman@postgrad.manchester.ac.uk

Plants are almost always exposed to non-optimal temperature at times throughout their life cycle. In this paper, we have performed label-free proteomics approach to investigate the recovery responses ofArabidopsis thaliana(Col-0) of post warm-acclimation. Fully developed leaves were harvested from control (20°C/18°C) and recovery plants, which, were pre-acclimated to warm (30°C/25°C) for seven days prior to one-week recovery treatment. It is noticeable that total leaf protein content in recovery plants has increased although were previously warm-acclimated. Subsequently, proteomics analysis revealed that warm acclimation has induced changes of the proteome in recovery plants which mostly are categorised under stress response proteins, together with proteins that participate in photosynthesis and carbon metabolism pathways. These changes in leaf proteome suggesting the dynamic of acclimation and recovery mechanism in response to warm temperature in mature plants.

P8.17 SEASONAL SOURCE-SINK DYNAMICS IN SWITCHGRASS

Wednesday 5 July 2023 15:00

Mauricio Tejera- Nieves (Michigan State University, United States)

mauri@msu.edu

Perennial grasses show a clear yield decline after reaching maturity (3+ years of establishment). This aging response is well characterized in terms of changes in end-of-season biomass and could be related to lower leaf-level photosynthesis (i.e., net CO2 assimilation; Anet) in mature stands. Alternatively, these changes could be driven by environmental limitations exacerbated by older plants being larger in size. In mature

switchgrass (Panicum virgatum) stands, Anet decreased by ~ 50% during summer while rhizome starch reached peak concentrations around the same time that leaf photosynthesis fell to lower rates. These changes could be driven by water limitations as larger plants had larger water demands. Exclusion of rainfall by shelters across the entire growing season showed that water limitation did not alter these dynamics. Therefore, the reduced Anet in mature stands could be driven by sink limitations. To test the role of rhizome reserves and sink limitations on photosynthesis, we grew switchgrass plants from reserve-depleted rhizomes. A 30% decrease in rhizome starch increased whole-plant photosynthesis by increasing tillering 2-fold, leaf area by up-to 60%, and maintaining Anet constant. These results highlight how reduced sink limitations can effectively increase photosynthesis and carbon accrual in switchgrass. Altogether, our results suggest that changes in the source-sink balance of perennial grasses could drive the agerelated changes. As stands matures, starch reserves increase and stands become more susceptible to sink limitations leading to lower photosynthesis and potentially reduced yields. These findings present a novel strategy for yield improvement in perennial grasses.

P8.18 TWO PHYSIOLOGICAL MECHANISMS DICTATE THE SHORTTERM VARIABILITY OF MESOPHYLL CONDUCTANCE

Wednesday 5 July 2023 15:30

Florian A. Busch (University of Birmingham, United Kingdom), Meisha Holloway-Phillips (Swiss Federal Institute for Forest Snow and Landscape Research WSL, Switzerland), Hilary Stuart-Williams (Australian National University, Australia), Graham D. Farquhar (Australian National University, Australia)

f.a.busch@bham.ac.uk

The CO2 concentration present at the site of carboxylation is a key determinant of the rate of photosynthesis in C3 plants. Just as stomata restrict CO2 diffusion from the ambient air into the intercellular air space (IAS), mesophyll components restrict the diffusion from the IAS to the site of carboxylation. However, unlike stomatal conductance, the magnitude and nature of mesophyll conductance (gm ) has been highly debated over the years. Increasing evidence suggests that gm is not a constant, but variable in the short-term to changes in environmental parameters, such as CO2 concentration, light intensity, and temperature. However, to date, no conclusive agreement has been reached as to what are the major contributors to this variability.

We have previously experimentally shown that gm needs to be separated into a wall and a chloroplast component, which causes some of the observed variability of gm (Busch et al., Nature Plants 2020). Here, we report a second physiological mechanism that influences how gm responds to short-term environmental changes. We show that, in combination, these two mechanisms can explain most of the sensitivity of gm not just to one specific environmental parameter, but to the whole range of the parameters we looked at. This allowed us to formulate for the first time a mechanistic model that well-describes the short-term variability of gm and that seamlessly integrates into the FvCB photosynthesis model. We expect this model to greatly advance our understanding of plant physiology and shine new light on the long-standing debates surrounding gm

P8.19 PLANT-FUNGAL SYMBIOSES AND THEIR RESPONSES TO CLIMATE CHANGE

Wednesday 5 July 2023 15:45

Katie J Field (University of Sheffield, United Kingdom)

k.j.field@sheffield.ac.uk

Fungi and plants have engaged in intimate symbioses that are now globally widespread and have driven terrestrial biogeochemical processes since plant terrestrialisation >500 Mya. These associations, known as mycorrhizas, are usually considered to be nutritional mutualisms, whereby the plant benefits from greater access to soil nutrients in return for transfer of photosynthetic carbon to their mycorrhizal fungal partners. The earliest land plants, which evolved in a high CO2 atmosphere, hosted diverse fungal symbionts which helped them access nutrient pools within primordial soils. It is generally thought that the rise of early non-vascular plants and the later evolution of plant roots and vasculature drove the long-term shift towards a high-oxygen, lowCO2 atmosphere and climate that eventually permitted the evolution of mammals and, ultimately, humans. Such shifts in atmospheric CO2 concentration, together with biotic factors such as plant and fungal identity, have been shown to impact exchanges of carbon for nutrients between plants and their mycorrhizal fungi. The effects of atmospheric CO2 concentrations and cultivar on crop-fungal carbon-for-nutrient exchanges remain critical knowledge gaps, particularly pertinent for exploitation of mycorrhizas for future sustainable agriculture in a changing climate. We are investigating the impact of climate change-relevant shifts in atmospheric CO2 concentrations in both wild and domesticated plant mycorrhizas. Our research suggests that mycorrhizas can contribute to sustainable crop production as part of a wider sustainable agriculture strategy and that there is substantial potential to improve future crop mycorrhizal receptivity, function and CO2 responsiveness.

P8.20 THE ROLE OF ABSCISIC ACID IN THE INTERACTION BETWEEN DROUGHT STRESS AND HERBIVORY IN BARLEY: A FIELD VS GREENHOUSE STUDY

Wednesday 5 July 2023 16:15

Chloe E Betts (University of Plymouth, United Kingdom), Anne Plessis (University of Plymouth, United Kingdom), James Buckley (University of Plymouth, United Kingdom), Michael Hanley (University of Plymouth, United Kingdom), Nicholas Smirnoff (University of Exeter, United Kingdom), Jennifer Poole (University of Plymouth, United Kingdom)

chloe.betts@plymouth.ac.uk

Abscisic acid (ABA) is a phytohormone that plays a key role in conveying information about the physicochemical conditions of plants and regulating multiple stress responses. Under stress conditions, ABA biosynthesis is upregulated leading to changes in growth and physiology in an attempt to protect the plant from the adverse effects of stress. While the role of ABA in controlling responses to many single abiotic stresses has been well-characterised in controlled laboratory and greenhouse conditions, these studies cannot be assumed to be translatable to agriculture where crops experience multiple

simultaneous stresses and fluctuating conditions. The role of ABA in coordinating the interaction between combined stresses in fluctuating field conditions remains unclear, yet understanding this is crucial in linking existing research to real-world applications in agriculture.

This study investigates the role of ABA in the interaction between drought stress and aphid (Rhopalosiphum padi) herbivory in barley (Hordeum vulgareL.) in moderately controlled greenhouse and fluctuating field conditions. Using statistical modelling I find that drought significantly decreases aphid reproduction in greenhouse conditions, but not in field conditions. In both conditions, aphid reproduction is not significantly affected by the ABA-deficient mutant (Az34). These results highlight the importance of field studies.

I also investigate the role of ABA in the interaction between droughtstress and snail herbivory on barley. I find that in laboratory conditions, drought decreases the amount of leaf tissue eaten by Cornu aspersum, however, ABA does not significantly affect this interaction. Future work will investigate this further in greenhouse and field conditions.

P8.21 SILICON AS A DEFENCE AGAINST BIOTIC STRESS IN PLANTS: A NEW MECHANISM TO EXPLAIN LOCALISED INDUCTION

Wednesday 5 July 2023

16:15

Sarah J Thorne (University of Sheffield, United Kingdom), Frans J. M. Maathuis (University of York, United Kingdom), Sue E. Hartley (University of Sheffield, United Kingdom) s.j.thorne@sheffield.ac.uk

Over 20 % of wheat yields are currently lost due to pests and pathogens, threatening global food security. Silicon is an important beneficial element that can improve crop tolerance to both abiotic and biotic stresses. However, these benefits of silicon to plants vary significantly both between and within species and the mechanisms underpinning them remain unclear. For example, a current debate is the extent to which silicon uptake and distribution within plant tissues is actively directed by plants, or simply a consequence of passive transport in the transpiration stream. In this study, we investigated the effect of mechanical damage on silicon accumulation in ten genetically diverse wheat landraces. A localised increase in silicon accumulation was found in all landraces, with damage increasing silicon accumulation between 34 and 108 % depending on the landrace, but only in the damaged leaves of damaged plants. This localised response results from the redirection of soluble silicon from undamaged to damaged plant parts within the damaged plants. The data suggests that soluble silicon enters the phloem and is redistributed around the plant to the sites of damage where it is required for active defence. These findings indicate that there is more plasticity in the use of silicon as a defence by plants than previously hypothesised: silicon is directed to sites of wounding whereas it was previously considered relatively immobile within plants. This active plant response could have significant benefits for sustainable crop protection.

P8.22 DISSECTING MESOPHYLL CONDUCTANCE, CO2 GRADIENTS IN THE MESOPHYLL AIR SPACE

Wednesday 5 July 2023 16:15

Diego A. Márquez (University of Birmingham, United Kingdom), Graham D. Farquhar (Australian National University, Australia), Florian A. Busch (University of Birmingham, United Kingdom)

diego.marquez@anu.edu.au

Quantifying the intercellular CO2 concentration in the airspace of the leaf is key to interpreting and understanding physiological traits and genetic variation of photosynthesis. Over the range of CO2 concentration within the mesophyll air space, a minimum CO2 concentration must drive the gradient inward toward the mesophyll cell walls from the adaxial and abaxial surfaces. Mesophyll cells are the sink of CO2; thus, the CO2concentrations surrounding them are the lowest in the leaf air space. The CO2 must diffuse through the gaseous phase of the mesophyll air space and then through the liquid phase at the surface of the cell wall to the chloroplast stroma. The conductance offered in the latter liquid path is usually referred to as mesophyll conductance (gm) and estimated, assuming that the resistance and gradient in the air space are negligible. We showed that this later assumption incorporates a significant error in the estimations of gm. Thus, obtaining a more accurate estimate of the gm accounting for the gradients of CO2 within the mesophyll air space is possible.

Therefore, we explored the role of reduced canopy transpiration on plant tissue nutrient concentration under elevated [CO2], which reduces the transpiration-driven mass flow of nutrients.

P8.24 ELEVATED CO2 DID NOT ALLEVIATE THE EFFECT OF EARLY EXPOSURE OF MAIZE SEEDLINGS TO SUBOPTIMAL TEMPERATURES

Wednesday 5 July 2023 16:15

Khadija Boughazi (Forschungszentrum Jülich, Germany), Onno Muller (IBG-2: Plant Sciences Institute for Bioand Geosciences Forschungszentrum Jülich, Germany), Carel Windt (IBG-2: Plant Sciences Institute for Bioand Geosciences Forschungszentrum Jülich, Germany), Uwe Rascher (IBG-2: Plant Sciences Institute for Bioand Geosciences Forschungszentrum Jülich, Germany), Fabio Fiorani (IBG-2: Plant Sciences Institute for Bioand Geosciences Forschungszentrum Jülich, Germany), Nathalie Wuyts (IBG-2: Plant Sciences Institute for Bioand Geosciences Forschungszentrum Jülich, Germany)

k.boughazi@fz-juelich.de

Wednesday 5 July 2023 16:15

Terence Seldon K Kwafo (University of Illinois Urbana Champaign, United States), Justin M McGrath (University of Illinois Urbana Champaign and USDA-ARS, United States)

skwafo@illinois.edu

Elevated atmospheric carbon dioxide concentrations (elevated [CO2]), an aspect of global climate change, increases yield in crops such as soybean through enhancement of photosynthetic rate and total biomass but it reduces concentrations of mineral nutrients, including iron (Fe) and zinc (Zn), and proteins. Given the expected increase in atmospheric [CO2], crops grown in future climates are likely to have reduced concentrations of minerals critical for human diets. Despite increases in yield, the reduction in crop quality could have detrimental impacts on human health; deficiencies in essential dietary nutrients can result in malnutrition disorders and diseases regardless of adequate caloric intake. Thus, in addition to the need to double global crop production in order to meet the projected demands of a rising population, the nutritional quality of those crops should be considered as well. Developing ways to improve crop quality and adapt crops to climate change would be benefited by understanding the mechanisms of nutrient uptake and distribution and the mechanisms by which growth in elevated [CO2] reduces nutrient concentrations.

Maize originated from warm sub-tropical regions. However, it is a crop currently cultivated worldwide, including under temperate climates. The crop cycle in the Northern Hemisphere begins during spring, where maize seedlings can be subjected to suboptimal temperatures driven to an extent by climate change. In parallel, increasing levels of atmospheric CO2 concentrations could contribute to conditioning crop productivity. Therefore, adaptive mechanisms of crops to future conditions need deeper understanding. We conducted an experiment evaluating 13 Doubled Haploid lines derived from a German Flint landrace “Petkuser Ferdinand Rot” and a dent inbred line (B73). The genotypes contrasted in their cold tolerance levels from seedling phase and showed a delay in their growth due to low temperatures [20/12°C – day/night]. Elevated CO2 concentrations (eCO2; 800ppm) did not mitigate the cold stress responses of seedlings: maximal photochemical efficiency of Photosystem II (PSII) and chlorophyll content were comparable between seedlings of the same genotype exposed to a combination of cold with either ambient (400ppm) or eCO2. Photochemical efficiency of dark-adapted leaves remained below 0.6 under both CO2 concentrations and for genotypes from different cold tolerance levels. In addition, the pre-treated seedlings showed a reduction in their biomass when they were transferred to ambient air and greenhouse conditions, in comparison to cold stressed seedlings under ambient air. The observed decrease in biomass highlights a possible effect of eCO2 on carbon assimilation and allocation for the studied C4 species, which needs to be elucidated by the examination of light-independent reactions of photosynthesis of maize.

Wednesday 5 July 2023 16:15

P8.26 ROOTING FOR IMPROVED WHEAT ROOT RESPONSES TO SOIL COMPACTION STRESS

P8.23 IDENTIFYING THE RELATIONSHIP BETWEEN TRANSPIRATION AND NUTRIENT ACQUISITION UNDER GROWTH IN ELEVATED ATMOSPHERIC CO2 CONCENTRATION IN SOYBEAN

Lucia Nevescanin-Moreno (University of Nottingham, United Kingdom), Riccardo Fusi (University of Nottingham, United Kingdom), Craig Sturrock (University of Nottingham, United Kingdom), Brian Atkinson (University of Nottingham, United Kingdom), Simon Griffiths (John Innes Centre, United Kingdom), Sacha Mooney (University of Nottingham, United Kingdom), Francisco Pinto (International Maize and Wheat Improvement Center (CIMMYT), Mexico), Matthew P. Reynolds (International Maize and Wheat Improvement Center (CIMMYT), Mexico), Malcolm Bennett (University of Nottingham, United Kingdom), Bipin Pandey (University of Nottingham, United Kingdom)

antonia.nevescaninmoreno@nottingham.ac.uk

Soil compaction is a major problem for root growth affecting the water and nutrients intake causing yield reduction leading to economic losses and food insecurity. Conventional thinking states roots are unable to penetrate compacted soil due to the mechanical force required. Recently it has been discovered roots can penetrate compacted soils after disrupting their sensitivity to the gaseous hormone ethylene, meaning plants use ethylene as a sensor for soil compaction (Pandey et al, 2021). This work aims to apply this novel concept to explore the natural allelic variation in wheat root ethylene response and how this can be translated into adaptation to soil compaction and textures. To achieve this, we developed a high throughput screening for ethylene sensitivity in wheat genotypes (Watkins landrace collection and CIMMYT) assessing their root growth inhibition. Selected genotypes were tested in compacted soil using X-Ray Computed Tomography, revealing reduced root ethylene sensitivity correlated with compaction resistance. To explore the influence of soil properties on root ethylene sensitivity, soil texture geographical information was compared to where landraces have been historically grown. Our results revealed the diversity in wheat root ethylene response correlated with contrasting soil textures. This work is part of a major project (BBSRC BREAKTHRU) which aims to re-engineer wheat roots to be more compaction stress resistant.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

P8.27 LONG TERM ELEVATED CARBON DIOXIDE EXPOSURE PENALIZES N2 FIXATION AND OLSEN P IN A GRAZED GRASSLAND ECOSYSTEM

Wednesday 5 July 2023 POSTER SESSION

Zac Beechey-Gradwell (AgResearch, New Zealand), Paul Newton (AgResearch, New Zealand), Mark Lieffering (AgResearch, New Zealand), Saman Bowatte (AgResearch, New Zealand)

zacbeechey@gmail.com

Elevated carbon dioxide (eCO2) levels in the atmosphere increase photosynthesis, WUE, and plant productivity via the ‘CO2 fertilization effect’ (CFE). Long-term ecosystem responses to eCO2 may also include changes in properties such as botanical composition and soil nutrient

availability. A central question for ecosystems reliant on N2 fixation by legumes is whether enhanced N2 fixation under eCO2 will alleviate nitrogen (N) limitations of the CFE. The New Zealand Free-Air CO2 Enrichment experiment (NZ-FACE) was established in 1997 to study the long-term plant and soil responses of a grazed grassland ecosystem to eCO2. The facility is unique due to the inclusion of grazing animals and from a fertility management perspective because the pasture relies on legumes for all de novo N inputs, while non-N nutrients are externally applied. Analysis of the long-term NZ-FACE plant and soil dataset revealed an initially positive effect of eCO2 on legume production/ proportion and pasture N concentration which declined with duration of CO2 enrichment. Another significant finding was that eCO2 had a negative impact on plant-available P (Olsen P) in the soil, although this effect diminished with duration of CO2 enrichment. The eCO2 driven changes in N and P supply both had a negative feedback effect on the size of the above-ground CFE. Work is ongoing to understand possible mechanisms by which grassland N2 fixation and Olsen P are penalized under eCO2. If widely applicable, these eCO2 driven changes in fertility could suppress grassland growth responses to increasing atmospheric CO2

P8.28 INTERACTIVE EFFECT OF LATE AUTUMN WARMING AND SPRING DAYLENGTH ON BUDBURST OFFAGUS SYLVATICA L.

Wednesday 5 July 2023 POSTER SESSION

Romain A. M. GARRIGUES (University of Antwerp, Belgium), Inge DOX (University of antwerp, Belgium), Omar FLORES (University of Antwerp, Belgium), Lorène J MARCHAND (University of Antwerp, Belgium), Andrey V. MALYSHEV (University of Antwerp, Germany), Gerrit BEEMSTER (University of Antwerp, Belgium), Hamada ABDELGAWAD (University of Antwerp, Belgium), Ivan JANSSENS (University of Antwerp, Belgium), Han ASARD (University of Antwerp, Belgium), Sebastian WIENEKE (University of Leipzig, Germany), Matteo CAMPIOLI (University of Antwerp, Belgium) romain.garrigues@uantwerpen.be

It is crucial to understand and simulate how temperate deciduous forests respond to climate change and how abiotic drivers (i.e. temperature and daylength) affect dormancy depth and next year spring budburst. Recent studies have shown that warming can decrease the chilling accumulation, and increase dormancy depth, inducing delayed budburst in European beech (Fagus sylvatica L). Whether fall warming can also advance spring phenology is unclear. We investigated the combined, and separated, effects of warming during late autumn (+ 2.5-3.5°C; temperature on average kept at 10°C, during two dormant seasons) and of daylength in winter-spring (treatment by LED, in winter- spring) on the dormancy depth and spring budburst of Fagus sylvatica. Even though warming reduced chilling in both years, we observed that the response of dormancy depth and spring budburst were year-specific. Under normal daylength, this reduced dormancy depth during endodormancy resulted in advanced spring bud burst even if dormancy depth differences between warmed and not warmed trees were not significant in late winter – early spring. Under shorter daylength, no advancement in budburst following autumn warming took place, likely because the minimal photoperiod threshold for budburst to occur was reached. On the other hand, the different daylength treatments did not elicit differences in spring leaf-out in trees that were not warmed. These results suggest that budburst

timing is limited by autumn temperatures, but that the short-daylength photoperiodic threshold has a stronger control and can overrule the effect of autumn warming.

P8.30 DYNAMIC PHOSPHORYLATION OF RIBOSOMAL PROTEIN S6A ENSURES THE SUCCESSFUL DEVELOPMENT OF YOUNG ARABIDOPSIS SEEDLINGS

Wednesday 5 July 2023 POSTER SESSION

Yueh Cho (Institute of Plant and Microbial Biology Academia Sinica, Taiwan), Guan-Hong Chen (Institute of Plant and Microbial Biology Academia Sinica, Taiwan), Shu-Hsing Wu (Institute of Plant and Microbial Biology Academia Sinica, Taiwan)

shuwu@gate.sinica.edu.tw

Translation is enhanced by light in de-etiolating seedlings. We previously showed that a pathway involving auxin, target of rapamycin, and ribosomal protein S6 (RPS6) regulates this enhancement. Light also triggers a cascade of phosphorylation of RPS6; however, the biological relevance of multi-phosphorylation of RPS6 in photomorphogenesis remains elusive. The expression of pRPS6A:RPS6A-FLAG in rps6a functionally complemented the developmental defect of the rps6a mutant and allowed the immunoprecipitation of RPS6A-FLAG proteins. Mass spectrometry was employed to identify and quantify the phosphorylation of individual serine or threonine residues of RPS6A in response to light signals. Among the seven C-terminal putative light-responsive phosphorylation sites, serine-229 (S229), S231, and S237 or S240 were the seed sites for sequential phosphorylation. The expression of phospho-null (PN) or phospho-mimic (PM) versions of RPS6A can only partially complement the rps6a phenotypes, including the reduced hypocotyl elongation of etiolated seedlings and lightinduced cotyledon opening. Together with the reduced PSII activity, the accumulation of LHCB1 protein in PM plants, and the compromised light-enhanced translation in both PM and PN plants, our data suggest the dynamic phosphorylation of RPS6A enables the full function of RPS6A. Our study provides a comprehensive view of the contribution of the multi-phosphorylation of RPS6A in ensuring a full capacity of photosynthetic activity and the translation of photosynthetic mRNAs for successful de-etiolation.

P8.31 THE ROLE OF ABSCISIC ACID IN COORDINATING DROUGHT STRESS RESPONSES IN GREENHOUSE VS FIELD CONDITIONS

Wednesday 5 July 2023

POSTER SESSION

Chloe Betts (University of Plymouth, United Kingdom), Anne Plessis (University of Plymouth, United Kingdom), James Buckley (University of Plymouth, United Kingdom), Michael Hanley (University of Plymouth, United Kingdom), Nicholas Smirnoff (University of Exeter, United Kingdom), Jennifer Poole (University of Plymouth, United Kingdom)

chloe.betts@plymouth.ac.uk

Abscisic acid (ABA) is a phytohormone that plays a key role in conveying information about the physicochemical conditions in plants and regulating multiple stress responses. Under stress conditions, ABA biosynthesis is upregulated leading to changes in plant growth and physiology in an attempt to protect the plant from the adverse effects of stress.

While the role of ABA in controlling responses to many single abiotic stresses has been well-characterised in controlled laboratory and greenhouse conditions, these studies cannot be assumed to be translatable to agriculture where crops experience multiple simultaneous stresses and fluctuating conditions. The role of ABA in coordinating responses to stresses in fluctuating field conditions remains unclear, yet understanding this is crucial in linking existing research to real-world applications in agriculture.

This poster presents my research investigating the role of ABA in the coordination of drought stress responses in barley (Hordeum vulgareL.) in different levels of uncontrolled and fluctuating conditions (containers in greenhouse conditions, containers outside, and field conditions). I find that proline synthesis and growth are affected by drought differently in these locations, highlighting the importance of field studies.

I also investigate the role of ABA in the interaction between drought stress and aphid (Rhopalosiphum padi) herbivory in barley grown in these three conditions. Using statistical modelling I find that drought significantly decreases aphid reproduction in more controlled conditions, but not in field conditions. This further demonstrated the importance of field studies. In all conditions, aphid reproduction is not significantly affected by the ABA-deficient mutant (Az34).

P8.32 VARIATION IN

PHOTOSYNTHETIC PHYSIOLOGY ASSOCIATED WITH CRASSULACEAN ACID METABOLISM ACROSS THE DIVERSE GENUS KALANCHOË

Wednesday 5 July 2023

POSTER SESSION

Maryam I Subaylaa (The University of liverpool, United Kingdom), James Hartwell (The University of Liverpool, United Kingdom)

M.Subaylaa@liverpool.ac.uk

The genus Kalanchoë(Crassulaceae) represents an ideal model system for studying the Crassulacean acid metabolism (CAM) adaptation of photosynthetic CO2 assimilation, both in terms of CAM evolution and the underpinning molecular-genetic blueprint used to achieve an optimised CAM system. Kalanchoë species are known to vary from C3 with drought-inducible weak CAM, through to full and strong CAM. Earlier work classified the genus into three taxonomic sections, namely Kitchingia, Bryophyllum and Eukalanchoe, and correlated CAM physiology and C3-CAM flexibility with these evolutionary groups within the genus. However, this work relied mostly on delta-13C values to determine the level of CAM, and few Kalanchoë species have been studied in detail in terms of their daily cycle of CO2 fixation and stomatal control. In order to better understand the diversity of CAM physiotypes in Kalanchoë, the 24 h gas exchange pattern was measured for a wide diversity of Kalanchoë species. The selected species possess a broad spectrum of leaf and stem morphological traits, with representatives from each taxonomic section. Gas exchange of different developmental leaf ages was measured, providing valuable insights into increasing levels of CAM-associated dark CO2 fixation as leaves develop and mature. Using these complementary datasets, the level of CO2 fixation in the dark and light periods was quantified, compared and contrasted across Kalanchoë species. Current results

suggest that individual species within each taxonomic section can display a high-degree of CAM flexibility, and that leaf thickness does not seem to reflect the level of CAM.

P8.33 PHENOTYPIC COMPONENTS OF C2 PHOTOSYNTHESIS

Wednesday 5 July 2023

POSTER SESSION

Hattie Roberts (Lancaster University, United Kingdom), Roxana Khoshravesh (Lancaster University, United Kingdom), George Rumble (Lancaster University, United Kingdom), Marjorie R Lundgren (Lancaster University, United Kingdom)

h.roberts7@lancaster.ac.uk

C2 photosynthesis is a rare physiology used by just over 50 species from 20 plant lineages representing 11 plant families. Also called the glycine shuttle or photorespiratory CO2 pump, C2 photosynthesis is a simple CO2 concentrating mechanism that shuttles, concentrates, and recaptures CO2 released by photorespiration. Thus, the C2 system upgrades C3 photosynthesis to improve re-assimilation of photorespired CO2 and partially suppress photorespiration. These benefits effectively boost rates of net photosynthesis, especially under warm, arid, or bright environments that promote high rates of photorespiration. While research on C2 photosynthesis is growing, few studies have taken an overview approach to determine which traits are common across diverse C2 lineages. This poster will present a comprehensive overview of the phenotypic components of C2 photosynthesis. Using a combination of published data and newly acquired measurements, we collate leaf anatomy, ultrastructure, biochemistry, and physiology data from diverse C2 plants to determine the phenotypic components that are consistently affiliated with this unique physiology.

P8.34 ON THE CONTRIBUTION OF SHOOT WATER TO TRANSPIRATION IN FABA BEAN AND SUNFLOWER

Wednesday 5 July 2023 POSTER SESSION

Dagmar Van Dusschoten (Ibg-2 Forschungszentrum Juelich, Germany), Daniel Pflugfelder (Ibg-2 Forschungszentrum Juelich, Germany), Johannes Kochs (Ibg-2 Forschungszentrum Juelich, Germany)

d.van.dusschoten@fz-juelich.de

SWaP, the amount of water in the soil can be determined, allowing to disentangle the different water pools and their dynamics.

Experiments with the SWaP–balance combination under modulated light conditions with progressive soil dehydration for sunflower and faba beans were performed. Our data show that transpiration precedes RWU under wet conditions by several minutes. For progressively drying soil more and more of the transpired water originated from the shoot, not from the soil, sometimes exceeding RWU by a factor two. The combination of the SWaP and balance allows for a new way of looking at RWU as driven by transpiration and shoot water loss dynamics as it yields thus far inaccessible information about these dynamics.

P8.35 RESPONSES TO CYCLES OF DROUGHT AND FLOODING IN WHEAT AND BARLEY

Wednesday 5 July 2023 POSTER SESSION

Shukanta Saha (The University of Manchester, United Kingdom), Giles N. Johnson (The University of Manchester, United Kingdom)

shukanta.saha@postgrad.manchester.ac.uk

Climate change is increasing the frequency and intensity of stress events including drought and flooding and the responses of crop plants to stress combinations is unique. It is usually hard to deduce the combined effects of multiple environmental stresses by the known effects of single stress. Grass crops including rice, wheat and barley provide most calories to human diets. With expanding global populations, ensuring food security is increasingly difficult, especially with unpredictable severe weather patterns alongside contracting arable land. This research program aims to compare the responses of wheat and barley to cycles of contrasting environmental stress-drought and flooding. We will test the hypothesis that cycles of drought and flooding have a greater impact on yield than the sum of the two stresses applied individually. This will be tested in both wheat and barley studying physiological, biochemical responses and system biology approaches. It is predicted that combined stresses will have less impact on barley than wheat. In the present investigation, wheat and barley are being grown to study chlorophyll fluorescence, gas exchange and growth parameters under drought and flooding condition individually in the growth room. It will also be tested under both stress combinedly and in a cyclic way where system biology approaches will be studied. This project will provide information on most important factors impacting yield that compare yield variation in response to cycles of drought and flooding and findings will contribute valuable new data to help direct crop improvement programmes in cereals.

Water balance studies on trees typically show that transpiration (Tr) precedes xylem water transport or root water uptake (RWU). For herbaceous plants this delay is often taken to be negligible and water transport can be mostly treated as a purely resistive process. This is somewhat in contradiction with the observation that plants wilt over time when no water is supplied, clearly indicating a capacitive contribution to transpiration. Contrary to trees herbaceous plants can easily be grown in pots the weights of which can be determined using a balance. However, water moving between the soil and the shoot cannot be allotted and so growth determination requires additional information. Here we combined a balance with our Soil Water Profiler (SWaP) on the same soil-plant system. Using the

P8.36 INTERACTION BETWEEN SALINITY RESISTANCE AND INSECT HERBIVORY RESISTANCE IN HYBRID POPLAR

Wednesday 5 July 2023

POSTER SESSION

Sylvie Renault (University of Manitoba, Canada), Caitlin Moran (University of Manitoba, Canada), Sandamini Bandara (University of Manitoba, Canada), Diviansh Pandey (University of Manitoba, Canada), German Avila-Sakar (University of Winnipeg, Canada)

Sylvie.Renault@umanitoba.ca

Salinity and insect herbivory are abiotic and biotic stresses that have been primarily studied in isolation. However, in natural settings, plants are affected simultaneously by more than one stress. An initial stress could either increase or reduce the plant ability to respond to a subsequent stress. Four cultivars of hybrid poplars (Populus spp.) were used to determine if salt resistance affects resistance to insect herbivory by Orgyia leucostigma. Five-week-old hybrid poplar cuttings were hydroponically exposed to 0, 50 and 100 mM NaCl for a three-week period. Salt exposure resulted in decreased in leaf photosynthesis, transpiration and stomatal conductance while chlorophyll fluorescence and chlorophyll a content remained similar to the control plants. Lignin and glycine betaine content of leaves were not affected by salinity. Herbivory resistance was estimated from feeding assays using leaf discs. Constitutive and induced (following herbivory exposure) resistance were not significantly affected by salinity stress in all hybrid poplar cultivars in spite of some changes in the nutritional values of the salt-exposed leaves (total soluble carbohydrates, proteins and Na/K ratio). These results suggest that feeding preference of O. leucostigma was not altered by hybrid poplar response to salinity.

P8.37 DYNAMIC UBIQUITIN SIGNALING COORDINATES TRANSCRIPTIONAL REPROGRAMMING IN PLANT IMMUNITY

Wednesday 5 July 2023

Bushra Saeed (University of Edinburgh, United Kingdom), Daphne T. Homsma (University of Edinburgh, United Kingdom), Steven H. Spoel (University of Edinburgh, United Kingdom)

bsaeed@exseed.ed.ac.uk

Ubiquitination or covalent attachment of ubiquitin to a target protein is a major post-translational modification that affects the turnover, activity and/or localization of target proteins. Differential ubiquitination of proteins under varying environmental conditions serves as an important mechanism to precisely modulate the activity of key regulatory proteins. Ubiquitination of NPR1, a critical coactivator of the immune-responsive transcriptome, controls its transcriptional activity. Initial short-chain ubiquitination events have a positive effect on chromatin association of NPR1 and promote activation of immune-responsive genes. Subsequent elongation of ubiquitin chains, however, leads to proteasome-mediated degradation of NPR1, indicating that its activity depends on its ubiquitination status. Here, we employed a proteomics strategy to specifically identify interactors of transcriptionally active, short-chain modified NPR1. We are validating these putative NPR1 interactors and analyze the consequences of differential ubiquitination on their interaction with NPR1. Because dysregulation of master transcriptional coactivators can have detrimental effects on the genome, we also analyzed if differential ubiquitination of NPR1 affects genome stability. Our data indicates that when the enhanced activity of short-chain modified NPR1 is left unchecked, plants are more susceptible to DNA damaging agents. These findings suggest that fine-tuning of the ubiquitination status of NPR1 is a critical regulatory checkpoint to prevent transcription-

induced genome instability. Thus, our study provides new insights into the regulation of NPR1 activity by differential ubiquitination and begins to reveal how this controls transcriptional reprogramming, while preventing genome instability during establishment of immunity.

P8.38 IMPROVING CANE CROP RESILIENCE BY OVERCOMING THE LEGACY EFFECTS ON PHOTOSYNTHESIS FROM SHORT-TERM STRESSES

Wednesday 5 July 2023 POSTER SESSION

Ece Imam Moustafa (NIAB East Malling and University of Essex, United Kingdom), Tracy Lawson (University of Essex, United Kingdom), Amanda Cavanagh (University of Essex, United Kingdom), Andrew Simkin (University of Kent, United Kingdom), Mark Else (NIAB East Malling, United Kingdom)

ei20589@essex.ac.uk

Abiotic stresses are becoming more prevalent with the changing UK climate, with major effects on crop yield and quality. In cane crops, for example, raspberry, a transient stress imposes both an immediate physiological response (i.e., stomatal closure) and can also result in a legacy effect, whereby physiological processes are downregulated long-after the stress response, with longlasting effects on gas exchange and berry yield and quality. However, if these legacy effects could be predicted and overcome more rapidly, the risks to productivity could be better managed.

Therefore, a transient rootzone water deficit stress was imposed on Malling™ Bella, a commercial raspberry variety, to better understand the prolonged physiological recovery following substrate rewetting. The first detectable plant response to the imposed rootzone water deficit stress was a change in midday stem water potential values, followed by a fall in gs values and, later, a reduction in Class 1 yield. Following substrate rewetting, shoot water balance recovered within two days, but the legacy effects of transient water deficits on leaf gas exchange in cane crops were more persistent. Detailed diurnal measurements showed that even fifteen days after rewetting, afternoon values of gs in plants previously exposed to coir water deficits had not returned to well-watered values. Thus, legacy effects of transient rootzone water deficit can impose persistent limitations on raspberry productivity, though underlying mechanisms are not yet known.

Future work will determine the causal signals regulating the rate of recovery to better understand and manage legacy stress effects on productivity and berry quality.

Wednesday 5 July 2023

POSTER SESSION

Nabila J Juhi (University of Manchester, United Kingdom), Giles Johnson (University of Manchester, United Kingdom), Patrick Gallois (University of Manchester, United Kingdom)

nabila.juhi@postgrad.manchester.ac.uk

P8.39 FUM2, A GENE REQUIRED FOR PHOTOSYNTHETIC ACCLIMATION TO LOW TEMPERATURE, IS NOT REQUIRED IN FREEZING TOLERANCE.

FUM2 is a cytosolic fumarase responsible for the diurnal accumulation of fumarate in Arabidopsis thaliana. It has previously been found that this accumulation is essential for the dynamic acclimation of photosynthesis to low, non-freezing temperatures: plants lacking FUM2 show no improvement in photosynthetic capacity following a 7-day cold exposure. We take this further to ask whether fumarate accumulation is necessary for freezing tolerance. Freezing tolerance is an innate trait in plants from temperate climates, and this trait can be amplified through cold acclimation. Damage can be measured through ion leakage, as one of the main targets of freezing damage is the plasma membrane. Ion/electrolyte leakage assays allow a quantitative measure of damage. These assays show both non-cold acclimated and coldacclimated fum2 plants having no difference in freezing damage, thus tolerance. A theory behind this is that fum2 plants upregulate freezing tolerance genes more than its wild-type counterpart to compensate for its lack of photosynthetic acclimation. We decided to further study CBF and Cold Regulated (COR) gene expression in fum2. Higher CBF expression may result in higher expression of downstream COR genes, essential for the acquisition of freezing tolerance. Preliminary data shows fum2 plants have significantly higher CBF3 transcript levels in both non-cold acclimated, and cold-acclimated plants. Future experiments will focus on known downstream targets of CBF3, with the hypothesis that these genes will be found in higher abundance in fum2 than in wild-type.

P8.41 UNDERSTANDING THE ROLE OF LIGHT SIGNALS IN SUB-ZERO ACCLIMATION IN ARABIDOPSIS THALIANA

Wednesday 5 July 2023

POSTER SESSION

Kenji Sugita (Iwate University, Japan), Shunsuke Takahashi (Iwate University, Japan), Matsuo Uemura (Iwate University, Japan), Yukio Kawamura (Iwate University, Japan)

u3221005@iwate-u.ac.jp

Plants survive sub-zero temperatures by “cold acclimation (CA)”, which is the process to acquire freezing tolerance through shortterm exposure to low temperatures above 0°C. In addition, the cold acclimation plants get further enhanced freezing tolerance when they are exposed to mild freezing temperatures below 0°, and this is called "sub-zero acclimation (SZA)". However, studying about the molecular mechanism of SZA is very limited compared to CA as the experimental set up such as freezing stably and freezing under controlled light conditions is difficult to construct in the laboratory. Consequently, it is still unclear whether SZA follows a similar molecular pathway as CA. Hence, to understand the physiological conditions and the molecular mechanisms for SZA in Arabidopsis, we constructed the growth chamber that can stably freeze plants and control the light environment under sub-zero temperatures. Interestingly, the plant under light conditions during SZA (-2°) acquired more freezing tolerance compared to the plant under dark conditions during SZA. Therefore, to confirm whether chloroplasts are involved in SZA in the light, we gave the electron transfer inhibitor DCMU [3–(3,4-dichlorophenyl)-1,1-dimethylurea]. The plant in the presence of DCMU showed less freezing tolerance under light conditions compared with the plant in the absence of DCMU, suggesting that electron transfer is running during SZA in the light conditions in Arabidopsis leaves. Consistently, we observed that electron transport is running under freezing conditions by chlorophyll fluorescence analysis. Collectively, these results suggest that plants enhance further freezing tolerance through chloroplast signals during SZA in Arabidopsis.

P8.42 THE ROLE OF PLASTID TERMINAL OXIDASE (PTOX) IN BARLEY UNDER STRESS

Wednesday 5 July 2023 POSTER SESSION

Junliang Song (The University of Manchester, United Kingdom), Pablo Calzadilla (The University of Manchester, United Kingdom), Giles Johnson (The University of Manchester, United Kingdom)

junliang.song@postgrad.manchester.ac.uk

Photosynthesis is an important physiological process in plants that can be significantly impacted by abiotic stresses, which are becoming more prevalent due to global climate change. Plastid terminal oxidase (PTOX) has been identified as a positive regulator of plant stress tolerance, as it acts as an electron transport sink for photosystem II (PSII) and transfers electrons to oxygen to produce water. In this study, we examined the activity of PTOX in Barley (Hordeum vulgare) under salt stress. Ten-day-old barley plants were exposed to varying concentrations of salt (0mM, 200mM, 250mM NaCl) for ten days, followed by measurements of different photosynthetic parameters. To measure PTOX activity, we assessed the electron transport rate (ETR) under two different O2 concentrations (21%, 1%). We found that the PSII efficiency (ΦPSII) of salt-stressed plants was significantly higher than that of control plants, and that ETR of this were reduced nearly 30% under 1% O2. In contrast, control plants did not show the same oxygen sensitivity, suggesting that salt stress induces PTOX activity in barley. PTOX protein content was estimated in plants exposed to both control and stress treatments, the content increased significantly under ten days of salt treatment. Our results suggest that PTOX induced expression may serve as an acclimation response to stress in barley. Further experiments are underway to explore the mechanisms underlying PTOX regulation in this species.

P8.43 CROP BIOLOGY UNDER AGRIVOLTAICS SYSTEMS’ SKEWED SPECTRUM LIGHT

Wednesday 5 July 2023 POSTER SESSION

Oluwaseyi Ademola (University of Greenwich, United Kingdom), Francois Duvenage (University of Greenwich, United Kingdom), Arwa Selim (University of Greenwich, United Kingdom), Bill T Ferrara (University of Greenwich, United Kingdom), Richard Hopkins (University of Greenwich, United Kingdom), Elinor P Thompson (University of Greenwich, United Kingdom)

Oa4737q@gre.ac.uk

Agrivoltaics refers to the concurrent production of crops with solarderived electrical generation. It offers a means of generating ‘green’ energy while producing exploitable biomass and enhancing profit by reducing production costs. Semi-transparent, colour-tinted panels, in addition, permit light transmission, produce power for the farm/ growth house, and provide tailored lighting wavelengths for different growth processes and sector need. The aim of this project is to evaluate contrasting crop types and the positive and negative effects of growth under tinted systems. Root, leafy and soft fruit crops were compared under the skewed spectrum resulting from orange tinted panels, to understand their growth and biochemistry in such red-enhanced light

conditions. Plant growth, morphology and nutrient content were observed to differ in all crop types. Rocket and tomato biomass under tinted conditions showed a smaller reduction, when compared with neutral density shaded plants, than that of radish varieties. An increased protein content previously reported was consistently observed. Further aspects of biochemistry and fruit characteristics suggest other high value features may compensate for deleterious biomass effects.

P8.46 COMPARATIVE TRANSCRIPTOME, CO-EXPRESSION NETWORK, AND EQTL ANALYSES OFFER NEW INSIGHTS INTO PHOTOSYNTHESIS, CARBON FIXATION, AND RIBOSOME DEVELOPMENT IN RICE

Wednesday 5 July 2023

POSTER SESSION

Mamta Nehra (International Centre for Genetic Engineering and Biotechnology (ICGEB) New Delhi, India), Tanushri Kaul (International Centre for Genetic Engineering and Biotechnology (ICGEB) New Delhi, India), Sagar Sudam Jadhav (International Centre for Genetic Engineering and Biotechnology (ICGEB) New Delhi, India)

mamta1931nehra@gmail.com

Chloroplasts and photosynthetic pigments in leaf cells play a significant role in determining photosynthetic efficiency, as well as crop productivity, to a greater extent. Leaf color has been regarded as an essential agronomic trait in rice, majorly because any changes in leaf color have an impact on rice yield. In this study, M-745, a yellowgreen mutant of Nagina 22 (N22), was characterized and compared to the wild-type. The mutant showed significantly lower chlorophyll content, defective chloroplast morphology, and reduced photosynthetic capacity than the wild-type. The differentially expressed genes were identified in M-745 with respect to wild-type using RNA-Seq, which revealed the down-regulation of genes essential for synthesizing pigments and the photosynthesis pathway. In contrast, genes associated with chlorophyll degradation, carbon metabolism, starch and sucrose metabolism, and ribosome development were remarkably up-regulated in M-507. Co-expression networking revealed a substantial positive correlation between the expression profiles of the chloroplastic genes, transcription factors, and the genes involved in pigment metabolism and starch and sucrose metabolism. Furthermore, sequence similarity analysis revealed existing SNPs and InDels in M-745 compared to N22. The identified SNPs and InDels candidate genes have been found to have strong positive and negative expression quantitative trait loci (eQTLs). Additionally, transcription factor family genes, including NAC, bHLH, WRKY, AP2/ERF, and MYB, were also identified. These findings provide a possible pathway for the molecular mechanism associated with leaf color formation as well as a valuable resource for molecular marker development that will be critical for improving rice crop production efficiency

caitlin.moore@uwa.edu.au

Ensuring our native and managed ecosystems remain resilient to climate change is a global challenge facing humanity. To meet this challenge, we require a better understanding of how ecosystem processes, such as carbon and water cycling, respond to climate variability and extreme climate events. We also need to be able to link understanding of plant processes across scales to achieve this. My talk will focus on how my research has applied a suite of measurements and modelling approaches, in collaboration with a diverse team of people, to answer questions about photosynthesis from the enzyme to ecosystem scale.

P8.48 SEASONAL VARIATION IN THE RELATIONSHIP BETWEEN LEAF CHLOROPHYLL CONTENT AND MAXIMUM CARBOXYLATION RATE

Thursday 6 July 2023 09:30

Liyao Yu (National University of Singapore, Singapore), Xiangzhong Luo (National University of Singapore, Singapore leoyu31@outlook.com

Leaf chlorophyll content (Chl) as an easily retrievable parameter from satellite data, has been used as a proxy to estimate forest photosynthetic capacity, i.e., maximum carboxylation rate (Vcmax), which is crucial for improving carbon cycle modeling. However, the relationship between Chl and Vcmax is potentially affected by biotic (e.g., leaf age) and abiotic factors (i.e., long-term light condition), introducing seasonal variation in the relationship and hampering the accurate estimate ofVcmax using Chl. Combining newly observed field data and previously published data, this study investigated the seasonal variation inVcmax/Chl for multiple biomes across gradients of biotic and abiotic factors. We expect to quantify the respective contributions of leaf age and PPFD to the seasonal variation inVcmax/ Chl, which could be used to modify the static method (i.e., one linear regression ofVcmax on Chl for one plant functional type irrespective of seasons) that was used in previous studies. Together with leaf nitrogen data, our study provides insights into plant nitrogen use and partition strategy among light harvesting, carboxylation, and non-photosynthetic components over seasons, which could be incorporated to improve the estimation of Vcmax and alleviate the uncertainty in terrestrial carbon cycle modeling.

P8.49 SYNERGISING HYPERSPECTRAL AND THERMAL DATA TO MODEL PLANT RESPONSES TO ABIOTIC STRESS

Thursday 6 July 2023 09:45

Robert S Caine (University of Sheffield, United Kingdom), Muhammad S Khan (University of Sheffield, United Kingdom), Holly L Croft (University of Sheffield, United Kingdom)

b.caine@sheffield.ac.uk

Thursday 6 July 2023 09:00

Optimising nitrogen-based fertiliser use and water management strategies will be critical to sustainably enhancing future food production. However, distinguishing plants’ physiological response to

P8.47 SCALING PLANT PROCESSES FROM ENZYMES TO ECOSYSTEMS

Caitlin E Moore (The University of Western Australia, Australia)

different types of abiotic stress is not trivial. In this study, we investigate the physiological, biochemical and structural response of an elite British wheat (triticum aestivum) variety to nitrogen-deficiency and/ or drought treatment, and assess if thermal and hyperspectral remote sensing techniques could be used to model these plant responses over time. Near-simultaneous measurements of stomatal conductance, hyperspectral reflectance, infra-red gas analysis, leaf chlorophyll/ nitrogen content and thermal imaging were collected approximately every 5-8 days. Our results show that thermal imaging is a more dynamic tool for identifying early plant stress, whereas techniques such as hyperspectral imaging and chlorophyll content analysis are more important for detecting longer-term plant stress. By applying partial least squares regression analysis to leaf hyperspectral and relative water content (RWC) data, we create a new combined nitrogen and drought index (CNDI). We use CNDI to describe both nitrogen deficiency and late-stage drought (r2 = 0.66,P < 0.0001) and to improve evapotranspiration modelling derived from thermal imagery. Our work highlights the complementary, yet unique roles that thermal and hyperspectral imaging play in plant phenotyping and sets a marker for how multiple technologies might be used to optimise plant nutrient and water-use in the future.

Higher CO2 levels are altering leaf traits essential for optimal photosynthesis and crop yield, but the relationship between leaf structure and photosynthesis, and the quantitative importance of any single structural parameter remains open to debate. We report on eLeaf, a 3D model reaction-diffusion model that successfully captures rice leaf photosynthesis under different environmental conditions. The model is parameterised using a range of imaging data and biochemical measurements from plants grown under ambient and elevated CO2, then interrogated to quantify the importance of these elements. We identified photosynthetic metabolism as the primary contributor to the increased carbon assimilation rate under elevated CO2 levels, with a range of structural elements also making positive and negative contributions. eLeaf can quantitatively analyse the influence of individual morphological properties on leaf photosynthesis, highlighting that there is a degree of leaf structural plasticity with respect to photosynthesis – important in the context of attempts to increase crop efficiency. Mesophyll porosity could be varied without any major outcome on photosynthetic performance, providing theoretical underpinning for experimental data. We identified elements of leaf anatomy that enhance photosynthesis, laying a foundation for breeding efforts to future-proof rice. Future research aims to increase our understanding of rice mesophyll structure using improved 3D imaging techniques to explore the effect of mesophyll cell size and shape on photosynthesis.

P8.51 DEFINING THE SCOPE

FOR ALTERING RICE LEAF ANATOMY TO IMPROVE PHOTOSYNTHESIS: A MODELLING APPROACH

Thursday 6 July 2023 10:15

Jennifer M Sloan (University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom),

Yi Xiao (CAS Center for Excellence in Molecular Plant Sciences National Key Laboratory for Plant Molecular, China), Chris Hepworth (University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom), Marc Fradera-Soler (The University of Nottingham School of Biosciences, United Kingdom), Andrew Mathers (University of Nottingham School of Biosciences, United Kingdom), Rachel Thorley (The University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom), Alice Baillie (The University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom), Hannah Jones (The University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom), Tiangen Chang (CAS Center for Excellence in Molecular Plant Sciences National Key Laboratory for Plant Molecular, China), Xingyuan Chen (Pacific Northwest National Laboratory Biological Sciences, United States), Nazmin Yaapar (Universiti Putra Malaysia Department of Crop Science, Malaysia), Colin Osborne (University of Sheffield School of Biosciences

Plants Photosynthesis and Soil, United Kingdom), Craig Sturrock (The University of Nottingham School of Biosciences, United Kingdom), Sacha J Mooney (The University of Nottingham School of Biosciences, United Kingdom), Andrew J Fleming (University of Sheffield School of Biosciences Plants Photosynthesis and Soil, United Kingdom), Xin-Guang Zhu (CAS Center for Excellence in Molecular Plant Sciences National Key Laboratory for Plant Molecular, China)

j.sloan@sheffield.ac.uk

https://doi.org/10.1111/nph.18564

P8.52 CO2-FERTILIZATION IN SAVANNAS: INTERPRETING FIELD OBSERVATIONS WITH EXPERIMENTAL DATA

Thursday 6 July 2023

11:00

Colin Osborne (University of Sheffield, United Kingdom), Kimberley Simpson (University of Sheffield, United Kingdom), Carla Staver (Yale University, United States), James King (University of Sheffield, United Kingdom), William Bond (University of Cape Town, South Africa), Judith Botha (South African National Parks, South Africa), Corli Coetsee (South African National Parks, South Africa), Adam Pellegrini (University of Cambridge, United Kingdom), Sarah Raubenheimer (University of Michigan, United States), Brad Ripley (Rhodes University, South Africa), Maria Val Martin (University of Sheffield, United Kingdom)

c.p.osborne@sheffield.ac.uk

Rising atmospheric CO2 has the potential to transform ecosystems across the Earth, but detecting its real-world impacts in the field is challenging. Experiments, models and permanent plot data strongly implicate CO2 as a driver of change for tropical forest and savanna trees. However, equivalent evidence is lacking for the productive grassy ground layer of savannas. We have synthesised a meta-analysis of published experiments, field observations from decadal monitoring of permanent plots, and land surface model simulations. We argue that rising CO2 is having a measurable impact on the productivity of savanna grasses, despite the CO2-concentrating effects of their C4 photosynthetic pathway. Meta-analysis of experiments on wild C4 savanna and prairie grasses shows that CO2-fertilization interacts strongly with water availability. In particular, lower stomatal conductance under increasing CO2 in these species leads to water-savings and enhanced productivity, especially under dry soil conditions. At Kruger National Park in South Africa, this CO2-fertilization appears as a progressive increase in grass

productivity across three decades that is more pronounced at drier sites. Model simulations for southern Africa demonstrate the potential for CO2-mediated feedbacks from C4 savanna grasses on regional land surface hydrology, in the context of a warming, drying climate. The work has implications for understanding tree encroachment into savannas, which is thought to arise from CO2-fertilization of tree growth but is slower in drier ecosystems. Our data suggest that CO2mediated competition from savanna grasses at these drier sites may limit tree establishment.

P8.53 UNLOCKING THE MECHANISMS OF EUCALYPTUS PLASTICITY AND RESISTANCE; FROM THE MOLECULAR LEVEL TO THE FIELD

Thursday 6 July 2023 11:30

Orobanchaceae) under present-day and increased CO2 concentrations. In both setups, the parasite was grown with a grass and legume host simultaneously, which is coherent with the biology of species and its natural growth mode. Results showed that although no difference was detected in the overall growth rate of parasitic plants, those under an elevated CO2 flowered one week earlier than their counterparts. Isotopic analyses also suggest that under an enhanced CO2 concentration, parasitic plants might become more water use efficient and accumulate more carbon. However, no differences were detected regarding photosynthesis and biomass accumulation in the parasites. This is in remarkable contrast to other studies in which parasitic plants were cultivated under similar CO2 conditions, but with access to only one host plant per pot. This contrast might be explained by differences in host growth. Under enhanced CO2 conditions, grasses grew faster and produced more biomass than those under control conditions. No differences were observed for legume hosts. This suggests that in future climatic scenarios, grass hosts might become more important for the growth of O. vulgaris than legumes. Ultimately, these differences might impact community composition due to changes in host preferences by the parasite.

en@plen.ku.dk

The hyper-diverse Eucalyptus genus is economically and ecologically important. Eucalyptus are keystone species that dominate 92 million hectares of native Australian forests and woodlands, with a range spanning many diverse, and sometimes extreme environments. Commercially, Eucalyptus trees are the most widely planted hardwood, with over 20 million hectares of dense global plantations. The ability of Eucalyptus to thrive in different environments is due, in part, to their ability to produce an extensive array of specialized metabolites essential for environmental interactions, such as mediating biotic and abiotic stress resistance. Using an “omics” toolbox, we aim to characterize how Eucalyptus species regulate specialized metabolite production; from the molecular level to the field. We have measured the concentration and localization of different volatile and non-volatile specialized metabolite classes in adult trees, showing distinct quantitative and qualitative variation based on eucalypt species, environmental condition, and tissue type. Pathway discovery studies reveal dynamic evolution of specialized metabolite biosynthesis, with recruitment of novel enzyme families within the genus and possible links to a high degree tandem genomic gene repeats. The knowledge generated expands our fundamental understanding of Eucalyptus plasticity, which will ultimately aid the conservation of these most iconic trees.

P8.54 EFFECTS OF CLIMATE CHANGE ON THE ECO-PHYSIOLOGY OF PARASITIC FLOWERING PLANTS

Thursday 6 July 2023 11:45

Luiza Teixeira-Costa (Vrije Universiteit Brussel, Belgium), Gerhard Zotz (Carl von Ossietzky Universität Oldenburg, Germany)

luiza.teixeirac@gmail.com

The impacts of climate change on parasitic interactions are of special concern and interest, given that this type of ecological relationship can lead to broader ecosystem alterations. To better understand the effect of atmospheric CO2 on the interaction between parasitic flowering plants and their hosts, we cultivated a hemiparasite (Odontites vulgaris,

P8.55 SEEING THE FOREST FOR THE TREES: INSIGHTS INTO THE EVOLUTION OF C4 PHOTOSYNTHESIS FROM TREEFORM HAWAIIAN EUPHORBIA

Thursday 6 July 2023 12:00

Sophie N R Young (Lancaster University, United Kingdom), Marjorie R Lundgren (Lancaster University, United Kingdom)

s.young5@lancaster.ac.uk

One of the largest lineages of plants utilising the C4 photosynthetic pathway is found in Euphorbia (Euphorbiaceae), a remarkably photosynthetically diverse genus that contains the only known true C4 trees. Why C4 trees have so rarely evolved is a long-standing question in ecophysiology and evolution, for which many explanations have been proposed. However, none of these explanations address the interaction between the photosynthetic and vascular systems; specifically, the loading of sugars produced by photosynthesis into the phloem. This may be an oversight given that modifications to phloem loading are now becoming recognised as an important factor associated with the evolution of C4 photosynthesis in cereal crops and, as such, we hypothesise that phloem loading may also be significant to the evolution of the C4 trait in trees. Here, we use leaf anatomical data obtained by confocal and transmission electron microscopy alongside data from sugar enzymatic assays to determine the phloem loading mechanism of photosynthetically diverse tree species from the Hawaiian Islands. These data are used to assess the validity of our proposed limitations to phloem loading in C4 trees, and establish whether phloem loading could be a factor contributing to the striking global rarity of trees using C4 photosynthesis.

Elizabeth H J Neilson (The University of Copenhagen, Denmark)

P8.56 SHAPED BY THE LIGHT: PHYSIOLOGICAL PLASTICITY IN RESPONSE TO RADIATION EXPLAINS ECO-EVOLUTIONARY PATTERNS ACROSS PHYLOGEOGRAPHIC LINEAGES OFOLEA EUROPAEAL.

Thursday 6 July 2023 12:15

Andres Barea-Marquez (University of Granada, Spain), Francisco Ocaña-Calahorro (University of Granada, Spain), Carlos Garcia-Verdugo (University of Granada, Spain), Miguel G. Ximenez-Embun (University of Granada, Spain), Rafael Rubio de Casas (University of Granada, Spain)

andbarmar@ugr.es

Understanding the factors underlying evolutionary adaptations of plants to different and changing environments has always been a key focus of biology. It is crucial for basic and applied research, especially now when ensuring crop resilience and food security is becoming pressing. The olive tree, Olea europaea L., is both a core element of the Mediterranean flora and a fundamental fruit crop. It harbors multiple well-differentiated genetic lineages, including six subspecies with different ploidy levels distributed across the Mediterranean, Africa and Macaronesia. These diverse lineages might harbor adaptations to various environmental limiting factors. Particularly, wild genotypes already growing in relatively lower latitudes might represent a natural experiment in adaptation to higher radiation and temperature. Here, we used a multi-scale eco-physiological experiment designed to test the differential response of 76 different genotypes belonging to six maternal lineages within three closely related subspecies of O. europaea to three light environments (control, high UV-B and shade). We analysed the phenotypic response across scales: leaf, whole plant, genotype and population using biochemical and morphological traits. Our results showed that although olive lineages have significantly different phenotypes overall, all genotypes are highly plastic. Phenotypic acclimation to the different environments indicated a high degree of conservatism across lineages. However, the response of certain traits was heterogeneous across lineages, maybe as a consequence of local adaptation. We conclude that the morphological and physiological plasticity of the different O. europaea lineages might be key to understand their ecology and agronomical potential.

P9 - CEREAL BIOLOGY IN 4D : GENE EXPRESSION ACROSS SPACE AND TIME

BY: ANNIS RICHARDSON (UNIVERSITY OF EDINBURGH), PHILIPPA BORRILL (JOHN INNES CENTRE)

ORGANISED

P9.1 PUT ON A BRAVE FACE: CONTROL OF EPIDERMAL FEATURES IN BARLEY

Tuesday 4 July 2023 09:00

Sarah McKim (Sarah McKim, United Kingdom), Linsan Liu (University of Dundee, United Kingdom), Sarah Jose (University of Bristol, United Kingdom), Chiara Campoli (University of Dundee, United Kingdom), Penny Von Wettstein (University of Copenhagen, Denmark), Trisha McAllister (University of Dundee, United Kingdom), Mhmoud Eskan (University of Dundee, United Kingdom), Linda Milne (The James Hutton Institute, United Kingdom), Micha M Bayer (The James Hutton Institute, United Kingdom), Luke Ramsay (The James Hutton Institute, United Kingdom), Robbie W Waugh (The James Hutton Institute, United Kingdom), Alistair Hetherington (University of Bristol, United Kingdom)

smckim@dundee.ac.uk

To sustainably feed the world’s population, we must develop cereal crops which reliably yield under intensifying temperature and precipitation extremes. Altering the cereal epidermis, the boundary layer between the plant inner tissues and the open air, is a promising route to improve crop performance and resiliency. In fact, plants adaptively modified their epidermis millions of years ago when they transitioned to live on land, secreting both a lipid-rich cuticle to prevent water loss and reflect incoming radiation, and developing regularly-spaced, adjustable air pores called stomata that regulate photosynthetic gas exchange and transpiration. Grasses, including our staple cereals, further specialised their epidermal surfaces, developing extremely efficient stomata and thick, waxy cuticles as well as epidermal hairs (trichomes), and silica cells, features which conserve water and ward off pests. Variation in these adaptive features could help engineer more resilient cereal crops, but first we must identify the genes controlling epidermal features and determine how they interact to influence cereal performance. In a major advance, our research group recently revealed that deeply conserved, interacting genes control both epidermal cell patterning and cuticle properties in barley. In my talk, I will present our work and new results about this upstream network which regulates multiple epidermal features linked to cereal performance.

P9.2 SPATIAL AND TEMPORAL REGULATION OF PLANT ORGAN GROWTH

Tuesday 4 July 2023 09:30

Hilde Nelissen (VIBUGent, Belgium)

hilde.nelissen@psb.vib-ugent.be

Plant organ growth is highly coordinated in time and space. The maize shoot apical meristem is an ideal system to study this spatial-temporal regulation: The successive leaves represent a temporal gradient in differentiation while the highly specific expression domains indicate the spatial regulation. By using spatial transcriptomics, we are now able to map the expression domains to the single cell level and to study the differentiation trajectories at the cellular level in tissue context. Combined with genetics, this approach allows the identification of novel regulatory circuits in the maize shoot apex.

P9.3 DELINEATING GENE REGULATORY NETWORKS AND BOUNDARY SPECIFICATIONS IN MAIZ

Tuesday 4 July 2023 10:00

Ayushi Gupta (Institute of Molecular Plant Sciences

University of Edinburgh, United Kingdom), George Chuck (USDA Plant Gene Expression Centre, United States), Andrea Eveland (Donald Danforth Plant Science Center, United States), Sarah Hake (USDA Plant Gene Expression Centre, United States), Annis Richardson (Institute of Molecular Plant Sciences University of Edinburgh, United Kingdom)

v1agupt8@ed.ac.uk

The genetic specification of boundaries between distinct tissues is critical for the development of complex organs such as the maize leaf. One of the most well-known genes for leaf boundary development in maize is LIGULELESS2 (LG2). lg2 mutants have defects in both vegetative and reproductive development, as lg2 leaves fail to form specialized structures (ligule and auricle) at the boundary between the sheath (lower leaf region) and blade (upper leaf region), while lg2 tassels (male inflorescence) have fewer branches and de-repressed bracts. This suggests that LG2 is repeatedly co-opted to regulate the development of diverse organs. However, the molecular mechanism(s) through which LG2 regulates and influences development remains unknown. We hypothesize that the different functions of LG2 arise through tissue-specific changes in its gene regulatory network (GRN). With this view, we are using ChIP-seq, RNA-seq, and CoIP to construct the LG2 GRNs underlying leaf and tassel development in maize.

P9.4 SPACEEX – A NOVEL PLATFORM FOR SPATIAL TRANSCRIPTOMICS IN PLANTS (AND BEYOND)

Tuesday 4 July 2023 10:15

Paride Rizzo (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Lothar Altschmied (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Mark Somoza (Leibniz Institute for Food Systems Biology at the Technical University of Munich (LSB), Germany), Erika Schaudy (Universität Wien, Austria), Axel Himmelbach (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany), Ivo Grosse (Martin-Luther University Halle-Wittenberg, Germany), Matthias MüllerHannemann (Martin-Luther University Halle-Wittenberg, Germany), Thorsten Schnurbusch (Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Germany)

rizzo@ipk-gatersleben.de

Spatio-temporal gene expression patterns are crucial to determine cellular decisions during development. In the long-lasting quest to address the positional information that shapes an organism, single-cell RNAseq and Spatial Transcriptomics technologies were developed as powerful tools to address gene expression in space and time.

In the last years, Spatial Transcriptomics underwent explosive growth, but until today, the available technology can address gene expression at sub-cellular resolution only for a limited set of genes. Alternatively, whole transcriptomes can be addressed at lower resolutions and at a high cost.

We are a team of Plant Biologists, Chemical Engineers, and Bioinformaticians from IPK-Gatersleben, Halle-Wittenberg University, Vienna University, and LSB Freising, involved in establishing a new methodology for studying gene expression in a spatially resolved way.

Here we present SpaceEx, a novel platform for Spatial Transcriptomics that uses a simplified, low-cost method for performing Spatial Transcriptomics at cellular resolution. We use a combination of (i) mRNA-capturing DNA oligos synthesized on the array and (ii) position-specific barcodes tolerant to synthesis error to investigate the transcriptomes of multiple plant tissues at the cellular level.

P9.5 UNDERSTANDING WHEAT SPIKE DEVELOPMENT FROM SYSTEMATIC VIEW AT SINGLE-CELL RESOLUTION

Tuesday 4 July 2023 13:30

Jun Xiao (Institute of Genetics and Developmental Biology CAS, China), Xuelei Lin (Institute of Genetics and Developmental Biology CAS, China), Yongxin Xu (Institute of Genetics and Developmental Biology CAS, China), Xuemei Liu (Institute of Genetics and Developmental Biology CAS, China), Weizhen Xue (BGI Genomics-Beijing, China), Dongzhi Wang (Institute of Genetics and Developmental Biology CAS, China), Long Zhao (Institute of Genetics and Developmental Biology CAS, China), Jingmin Kang (BGI Genomics-Beijing, China), Xueyong Zhang (Institute of Crop Sciences CAAS, China), Xiangdong Fu (Institute of Genetics and Developmental Biology CAS, China), Xiansheng Zhang (Shandong Agricultural University, China), Xin Liu (BGI Genomics-Beijing, China)

jxiao@genetics.ac.cn

Grain yield in wheat is heavily influenced by the number of grains per spike, which is determined by both the number of spikelets per spike and the number of grains per spikelet. This process is closely related to the progressive development of wheat inflorescence, a complex organ that comprises different meristem identities following flowering. In this study, we provide a comprehensive view of the genetic regulation network underlying wheat inflorescence development, using a combination of multi-omics data integration, population genetics, and functional validation via a tilling mutant library. Our analysis includes single-cell transcriptomic and chromatin accessibility data generated from inflorescence tissues at various developmental stages, from double ridge to terminal spikelet differentiation. By combining these data with spatial transcriptomic profiling, we reveal the transcriptome trajectory and chromatin dynamics during the progressive transition of different meristem identities. Time-series analysis uncovers celltype and developmental stage-specific epigenomic dynamics that are concordant with transcriptome changes. We also build a core transcriptional regulation network that is likely driving the meristem cell identity transition. By integrating this network with genomic DNA variation and spike-related phenotypes of collected wheat populations, we identify dozens of transcription factors, including SPLs, MADS, MYBs, bHLHs, YABs, TCPs, and NACs, as candidate key regulatory factors for spike development. We further confirm the roles of YAB4/5, SPL6, MADS34, and MYB3 in the regulation of spike development through genetic validation via tilling mutants and transgenic plants. Overall, our study provides new insights into the molecular regulation mechanism underlying wheat inflorescence development.

P9.6 PATTERNING A GRASS LEAF

Tuesday 4 July 2023 14:00

Annis Richardson (University of Edinburgh, United Kingdom), Jie Cheng (University of Chinese Academy of Sciences, China), R. Johnston (Cornell University, United States), R. Kennaway (John Innes Centre, United Kingdom), B. Conlon (Cornell University, United States), A.B. Rebocho (John Innes Centre, United Kingdom), H. Kong (University of Chinese Academy of Sciences, China), M. J. Scanlon (Cornell University, United States), S. Hake (ARSUSDA Plant Gene Expression Center, United States), E. Coen (John Innes Centre, United Kingdom) annis.richardson@ed.ac.uk

Grasses are the most agronomically important plant family, providing >50% of global calories through the consumption of staple cereal crops like wheat, maize and rice, in addition to their crucial roles as biofuels, and fodder for animals. This means that grasses, representing both staple and novel crops, will play a key role in developing a diverse, and robust future food supply. The shape of the grass leaf underpins their productivity, and the optimal shape can differ depending on environment and final product. With recent developments in gene editing, rapid generation of varieties with optimal leaf shape traits is now feasible, enabling precise matching of plant architecture to environment and use. However, we currently do not have a comprehensive understanding of the regulatory networks that define grass leaves and how they change over time and space, making it difficult to identify target genes, and predict the phenotypic outcome. Translating what is known from other model systems, like the eudicotArabidopsis thalianato grasses can be useful in this endeavour. However, in the case of leaves this is difficult as homology relationships have been debated for >100 years. By combining comparative genetics and computational modelling, we recently found that the same genetic pattern likely underpins both grass and eudicot leaf development, providing a framework to compare regulatory networks between species. But what do we know about

these genetic patterns? And what can we learn about the development of other grass organs by studying these genes?

P9.7 RICE PLANT AND FLOWERING STEM ARCHITECTURE; ROLES FOR THE TRANSCRIPTION FACTOR RFL IN MERISTEM FATE

Tuesday 4 July 2023 14:30

Usha Vijayraghavan (Indian Institute of Science, India), Sushmita Dutta (Indian Institute of Science, India), Sunita

Patro (Indian Institute of Science, India), Raghavaram

Peesapati (Indian Institute of Science, India), Heeba Anjum (Indian Institute of Science, India), Sara Simonini (University of Zurich, Switzerland), Ueli Grossnicklaus (University of Zurich, Switzerland)

uvr@iisc.ac.in

The above ground body shape and architecture of flowering plants in guided by the activity of primary (embryonically established) shoot meristems and lateral meristems (multipotent stem cells) formed at various positions of the body. During vegetative growth lateral meristems can form secondary axes of growth. In the reproductive phase lateral meristems can directly form flowers or form higher order indeterminate meristems before generating flowers. Thus the developmentally dynamic response of meristems determines plant shape.

To understand how seemingly identical meristems distributed along body axes respond to generate unique architectures we study rice RFL the homolog for the evolutionarily conserved transcription factor LEAFY (LFY). Arabidopsis thaliana LEAFY, a key regulator for floral development, activates floral organ patterning genes. We have shown that knockdown of rice RFLcompromised vegetative branching, caused delayed flowering, produced inflorescences with reduced branch complexity and very few florets. More recently usingrflgenome-edited mutant lines, with weak and strong alleles, we have reaffirm roles for RFL in reproductive transition, panicle branching, and grain yield. Transcriptome analyses in a partial loss of function mutant line, enabled the identification of some novel downstream pathways regulated byRFL. In parallel to investigate the direct gene targets of RFL in different rice meristems, we have performed ChIP-seq from young vegetative shoot meristems with incipient axillary meristems and also with young inflorescence meristems. These cumulative data give leads on functional divergence of rice RFL and on mechanisms by with it contributes to vegetative and inflorescence meristem fate.

P9.8 GRAIN-NACS ROLE IN BARLEY’S GRAIN DEVELOPMENT

Tuesday 4 July 2023 14:45

Isabel Mora-Ramírez (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany), Axel Himmelbach (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany), Thorsten Schnurbusch (Leibniz Institute f Plant Genetics and Crop Plant Research, Germany), Jos HM Schippers (Leibniz Institute of Plant Genetics and Crop Plant Research, Germany)

moram@ipk-gatersleben.de

Cereal production is one of the top-produced commodities worldwide, which makes the stability of their production crucial for food security worldwide. Due to the vast amount of land dedicated to cereal crops, research into their sustainable production and therefore understanding the diverse mechanisms of grain development and filling proves of major importance.

Transcription factors (TFs) bind to specific DNA sequences (ciselements) in the promoter regions of target genes to regulate their expression. In barley, TFs and their downstream gene regulatory networks (GRN) are poorly studied. We studied the GRN of six grainspecific NAC TFs during grain development. NAC TFs represent one of the largest TF families and are reported to play crucial roles during stress response and plant development. In Poaceae, several grainspecific NACs (Grain-NACs) have been associated with endosperm filling by regulating seed storage protein and starch accumulation in wheat and maize.

Here, we report the successful application of DNA affinity purification (DAP) followed by Next Generation Sequencing (NGS) for the identification of TF binding sites (BS) and target genes of GrainNACs using gDNA in its native state or amplified gDNA (ampDAP). The GRNs were dissolved in time by using three different grain developmental stages to assess not only novel TFBS for Grain-NACs, but to uncover novel regulatory networks involved in the regulation of grain development and filling. Our analysis indicates differential sensitivity of our analysed Grain-NACs to DNA methylation. Moreover, our results uncover a role for Grain-NACS in grain filling, suggesting that they might represent valuable breeding targets.

P9.9 THE SECRET GENETICS OF MAIZE VEINS

Tuesday 4 July 2023 15:30

Samuel Leiboff (Oregon State University, United States), Diana Ruggiero (Oregon State University, United States), Maria Camila Medina (Oregon State University, United States), Elena Shemyakina (University of California Berkeley, United States), George Chuck (University of California Berkeley, United States)

C4 grasses produce a dense parallel vein network, dynamically maintaining physiological functions as tissues grow and respond to the environment. Although maize vascular subtypes are similar in structure, their reiterative developmental programs provide a unique opportunity for specialization amongst veins generated at different times and locations. We test the hypothesis that spatiotemporal variation in gene regulation leads to unique development and physiology amongst veins in the same plant. Using tissue from a 942-inbred maize mapping panel grown across two replicated field seasons, we constructed a neural network image analysis pipeline that predicts vascular phenotypes from tens of thousands of cleared leaf scans. Leaf blades from most maize inbred lines commit 50-60% of leaf area to the production of vascular tissue, yet we detected substantial variation in overall vein subclass density and composition of total vein density, suggesting independent genetic architectures for each subclass. We observed natural variation in ectopic vascular bundle sheath fusion, a phenotype observed inscarecrow(scr),shortroot(shr), and related mutants. Fusion events were correlated with poor performance in North American inbred line field trials, suggesting that this phenotype is physiologically detrimental. Through GWAS we identified candidate genes and alleles correlated with each vascular trait, many have not been previously linked to vascular biology; functional analysis by reverse genetics and expression analysis is ongoing. Data derived from these aims will inform the precision breeding of specialized vascular traits for the continued improvement of maize to meet global demand for food, feed, and fuel.

P9.11

A TRANSCRIPTOMIC CELL ATLAS OF THE DEVELOPING BRACHYPODIUM LEAF AT SINGLE-CELL RESOLUTION

Tuesday 4 July 2023 16:30

Lea S Berg (Institute of Plant Sciences (IPS) University of Bern, Switzerland), Inés Hidalgo Prados (Centre for Organismal Studies (COS) Heidelberg University, Germany), Rashmi Tandon (Centre for Organismal Studies (COS) Heidelberg University, Germany), Paola Ruiz-Duarte (Centre for Organismal Studies (COS) Heidelberg University, Germany), Gabriel Deslandes-Hérold (Institute of Plant Sciences (IPS) University of Bern, Switzerland),

Michael T Raissig (Institute of Plant Sciences (IPS) University of Bern, Switzerland)

lea.berg@unibe.ch

The epidermis is the outermost layer of leaves and must fulfil distinct roles. It must both act as a barrier and simultaneously connect the plant with its environment. Distinct, specialised epidermal cell types provide this contrasting functionality. Some cell types like pavement cells provide stability and protect the inner leaf tissues against external abiotic and biotic stresses. In contrast, special epidermal pore complexes, the stomata, enable the exchange of gases between plant and the environment, which is required for photosynthesis and the regulation of water loss and transpiration. How these epidermal cell types are formed in grasses, however, is largely unknown. Here, we use single-cell RNA sequencing approaches to profile the transcriptome of developing cells in the leaf of the model grass Brachypodium distachyon. Our current dataset comprises the transcriptomes of more than 20000 cells of the developmental zone of the leaf, which cluster into the main tissues of the leaf–the epidermis, the mesophyll and the vasculature. Subsetting the epidermal clusters enables us to identify the major epidermal cell types and to imply a pseudo-temporal trajectory of developmental stages. In addition to data derived from wild type plants, we also profiled a mutant lacking a stomata-specific cell type to facilitate cluster annotation of different stomatal cells. Together, this unbiased approach will provide the basis to select and investigate novel players potentially required for the formation of specialised cell types in grass leaves.

Diversity in morphology of floral organs across all angiosperms poses interesting question on roles of conserved floral patterning genes in diverged species. One example of this diversity is rice lodicule; a small fleshy organ regarded as petal analogue. Lodicule shape and anatomy underlie its function in floret opening, permitting stamen emergence and cross-pollination. The roles of the conserved PISTILLATA paralogs; OsMADS2 and OsMADS4 floral patterning regulators in lodicule and stamen development are not fully appreciated, underlining the need for generating and characterizing their null mutants. Here we showed that osmads2 null mutant bears abnormal lodicules and unaffected stamens, reiterating prior reports of our group and from others that OsMADS2 roles are partially and fully redundant in lodicules and stamens, respectively. Importantly, osmads2 null mutants displayed novel phenotypes in floral organ number, symmetry, and flowering time. Disrupting OsMADS4 transcripts in osmads2-/- lines abolished lodicule function as it adopted entirely abnormal shape. Transformed lodicules had altered cell wall, cell shape, cell division and vasculature. These changes were more pronounced in osmads2-/- ;osmads4RNAi double mutants. Additionally, novel phenotypes in carpels, in inflorescence rachis elongation were noted. Interestingly, we uncovered a potential mechanism through which parthenocarpy is suppressed by these organ pattern regulators. Through RNA-Seq and ChIP-Seq analyses, we identified (in)direct target genes for these patterning factors whose regulation can contribute to the mutant phenotypes. Further, we gained new insights on divergence of these paralogous genes using complementation analysis. Overall, this study expands knowledge on the molecular mechanisms controlled by rice class B PI-like factors.

P9.13 GENETIC NETWORKS CONTROLLING CUTICLE SPECIALISATIONS IN BARLEY

Tuesday 4 July 2023

16:45

Tuesday 4 July 2023 16:45

Mohamed M M A Zamzam (Indian Institute Of Science

Bangalore, India), Sharad Singh (Indian Institute Of Science

Bangalore, India), Raghavaram Peesapati (Indian Institute Of Science Bangalore, India), Sandhan Prakash (Indian Institute Of Science Bangalore, India), Sara Simonini (Institute of Plant and Microbial Biology University of Zurich, Switzerland), Ueli Grossniklaus (Institute of Plant and Microbial Biology

University of Zurich, Switzerland), Usha Vijayraghavan (Indian Institute Of Science Bangalore, India)

mohamedm@iisc.ac.in

Trisha McAllister

(University of Dundee, United Kingdom) p.a.mcallister@dundee.ac.uk

Land plants cover their epidermis with a specialised protective layer called the cuticle, a feature which is crucial for surviving the perils of a terrestrial environment. While basic cuticle components are common to most plants, cuticles can vary widely in structure and composition to form highly specialised structures. One such specialisation is found on the barley grain, which is normally enclosed by a firmly adherent hull, a distinctive feature among cereals and a key quality trait for brewing and distilling industries. The SHINE transcription factor HvNUDUM (HvNUD) controls hull adhesion via modification of the grain cuticle, but the downstream regulatory network and developmental mechanisms underlying this trait are unknown. My research addresses this knowledge gap by studying genetic, structural and chemical changes in mutants showing grain skinning. Skinning refers to partial shedding of the hull, symptomatic of poor hull adhesion, which we propose may represent defects downstream of HvNUD. Here, I will discuss identification and characterisation of genes underlying skinning mutants, as well as ongoing efforts towards understanding the regulatory networks controlling cuticle specialisations.

P9.12 SHAPE DEFINES FUNCTION — EXAMPLE OF A RICE FLORAL ORGAN. UNRAVELLING THE GENETIC DETERMINANTS OF LODICULE DEVELOPMENT

P10 - UNLOCKING MEDICINAL PLANTS' FULL POTENTIAL THROUGH RIGOROUS APPLICATION OF PLANT SCIENCE PRINCIPLES

P10.1 MOLECULAR TOOLS TO BREED FOR HIGH FIBRE QUALITY IN HEMP

Wednesday 5 July 2023 09:00

Luisa M Trindade (Wageningen University Research, Netherlands), Jordi Petit (Wageningen University Research, Netherlands), Elma Salentijn (Wageningen University Research, Netherlands)

luisa.trindade@wur.nl

Hemp (Cannabis sativa L.) is a sustainable and high-yielding bast fibre crop with great potential in the emerging biobased economy. Fibre hemp is one of the oldest cultivated annual crops, traditionally grown for its long and strong fibres and seeds. The historical importance of hemp in Europe is well reflected by the abundance of cultivars, traditional landraces, and populations that were selected in the main areas of hemp cultivation throughout Europe (Salentijn et al., 2015). Breeding for different traits has been mostly done though traditional breeding methods such as mass selection. The sequencing of the first hemp genome in 2011 provide new insight in the genomic organization of hemp genomes and enabled the development of novel molecular tools for hemp breeding. In this talk I will present the different tools we have developed for hemp breeding with focus on fibre quality.

Reference:

Salentijn E.M.J., Zhang Q., Amaducci S., Yang M., Trindade L.M. 2015. New Developments in Fibre Hemp (Cannabis sativa L.) Breeding.Industrial Crops and Products.68:32-41

P10.2 REGULATION OF PACLITAXEL BIOSYNTHESIS IN CULTURED TAXUSCELLS

Wednesday 5 July 2023 15:00

Gary Loake (University of Edinburgh, United Kingdom)

G.Loake@ed.ac.uk

Gary J. Loake 1, 2, 3

Paclitaxel is a blockbuster anti-cancer drug, derived fromTaxus(yew) species, approved for the treatment of numerous cancers and also AIDS related Kaposi’s sarcoma. Further, the biomedical applications of paclitaxel continue to expand with treatments related to heart disease and potentially Alzheimer’s and tau related diseases. Thus, a secure supply of this World Health Organisation registered essential medicine is of central importance for human health.

Plant cell culture constitutes a sustainable biomanufacturing platform for the production of paclitaxel relative to forest harvest. However, despite the importance of this plant-derived natural product, significant details related to paclitaxel biosynthesis and the cognate regulation of this process remain to be established. Employing a variety of molecular approaches, we will outline our work on the regulation of paclitaxel biosynthesis.

References:

1. Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King’s Buildings, Edinburgh EH9 3BF, UK.

2. Centre for Engineering Biology, School of Biological Sciences, University of Edinburgh, King’s Buildings, Mayfield Road, Edinburgh EH9 3BF, UK.

3. Green Bioactives, Pentland Science Park, Penicuik EH26 0PZ, UK.

P10.3 THOSE LONG SUMMER DAYS: REGULATION OF FLOWERING TIME IN CANNABIS SATIVA

Wednesday 5 July 2023 15:30

Rainer Melzer (University College Dublin, Ireland), Caroline A Dowling (University College Dublin, Ireland), Jiaqi Shi (University College Dublin, Ireland), Matteo Toscani (University College Dublin, Ireland), Paul F McCabe (University College Dublin, Ireland), Susanne Schilling (University College Dublin, Ireland)

rainer.melzer@ucd.ie

Cannabis sativa is a morphologically extremely diverse species of significant pharmacological relevance. Cannabis is dioecious: it develops separate male and female plants. Some Cannabis cultivars are monoecious, however, with male and female flowers developing on the same plant. Furthermore, Cannabis is a long day plant, and flowering is only induced when day length is below a critical threshold; but photoperiod-insensitive cultivars exist.

ORGANISED BY: RICARDA JOST (LA TROBE UNIVERSITY, SUSANNE SCHILLING (UNIVERSITY COLLEGE DUBLIN)

Of particular pharmacological interest are the cannabinoids, which are only produced in the female inflorescence. Molecular mechanisms controlling sex determination and flowering time are therefore directly relevant to better understand the production of cannabinoids. We explore the genetic basis and the evolution of flowering time and sex determination in Cannabis by employing genomics, transcriptomics, genetic mapping and morphological studies. Our data indicate that sex determination and flowering time are genetically linked, and that one large-effect QTL is involved in controlling photoperiod insensitivity. We have identified an ortholog of FLOWERING LOCUS T as a candidate gene controlling photoperiod insensitivity. Massive sequence divergence between photoperiod sensitive and insensitive lines at the FLOWERING LOCUS T-like gene may have contributed to the evolution of photoperiod insensitivity.

P10.4 NORGALANTHAMINE N-METHYLTRANSFERASE CATALYSES THE LAST REACTION OF THE BIOSYNTHESIS OF ANTI-ALZHEIMER DRUG GALANTHAMINE.

Wednesday 5 July 2023 15:45

Nuwan S Liyanage (University of Quebec at Trois Rivieres, Canada), Natacha Mérindol (University of Quebec at Trois Rivieres, Canada), Sarah-Eve Gélinas (University of Quebec at Trois Rivieres, Canada), Basanta Lamichhane (University of Quebec at Trois Rivieres, Canada), Isabel Desgagné-Penix (University of Quebec at Trois Rivieres, Canada)

Nuwan.Sameera.Liyanage@uqtr.ca

In recent years, the research on Amaryllidaceace alkaloids (AA) gained momentum as galanthamine was approved as a drug to treat symptoms of Alzheimer's disease. In fact, Amaryllidaceae plants produce over 650 AA of diverse structures, many of which display therapeutical properties. Intriguingly, little is known on their biosynthesisin planta, and only a few of the implicated enzymatic reactions have been elucidated so far. Galanthamine, as well as many other AA are N-methylated compounds, a key modification for their activity, but the enzyme catalysing this reaction has yet to be identified. Thus, the goal of this project is to identify and characterise putative candidates responsible for AA N-methylation. Hence, N-methyltransferase (NMT) gene candidates were selected from Amaryllidaceae transcriptomic data, cloned into bacterial expression system and the produced enzymes were characterised for their ability to yield galanthamine. Moreover, we studied the differences in NMT expression in tissues of several species that produce galanthamine, and in response to natural stress conditions, using RT-qPCR. We also assessed NMT sub-cellular localisation in Nicotiana benthamiana heterologous system by confocal microscropy. Our results show that: 1) some candidates isoforms successfully methylated norgalanthamine to yield galanthamine, 2) NMT was more expressed in leaves compared to other tissues while, interestingly, galanthamine accumulation showed a different profile, 3) multiple environmental conditions upregulatedNMTlevels, and finally 4) the enzyme displayed cytosolic expression. The elucidation of the final step in galanthamine biosynthesis will provide new tools for metabolic engineering of plants or heterologous organisms to produce this pharmaceutically important drug.

P10.5 TRANSCRIPTIONAL PROFILING OF TWO MEDICINAL CANNABIS STRAINS WITH CONTRASTING CBD AND THC CONTENT GROWN UNDER GLASS HOUSE CONDITIONS

Wednesday 5 July 2023 16:00

Oliver Berkowitz (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Ricarda Jost (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Amelia Pegg (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Bhavna Hurgobin (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Sophia Ng (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Muluneh Oli (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Matthew T Welling (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia), Hannah Noorda (Cann Group Limited, Australia), Filippa Brugliera (Cann Group Limited, Australia), James Whelan (ARC Research Hub for Medicinal Agriculture La Trobe University, Australia)

o.berkowitz@latrobe.edu.au

The best studied compounds with pharmacological properties in cannabis (Cannabis sativa) are the cannabinoids delta-9tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the main psychoactive compound relevant in recreational drug use but also has beneficial analgesic and appetite-stimulating effects. CBD is non-psychoactive and has promising therapeutic properties for the treatment of, for example, schizophrenia and Alzheimer’s disease. While medicinal cannabis with high levels of THC has been selected by humans over centuries, high CBD producing cultivars had to be generated by crossing medicinal with hemp-type cannabis. These cultivars were selected based on the CBD content of flowers, often neglecting other features of traditional THC producing cultivars critical for overall performance in cultivation. Although the genes encoding the enzymes for cannabinoid biosynthesis have been identified, major differences in gene copy number exist among cultivars likely impacting cannabinoid profiles and content. Variation in genetic markers associated with other beneficial traits associated with, e.g., plant architecture and nutrient use, is less studied. We have performed RNA-seq and PacBio Iso-seq on four organs (roots, stem, leaves, flowers) collected from two cannabis cultivars contrasting in their cannabinoid profiles and grown under glass house conditions. Subsequently, expression of genes was correlated to tissue concentrations of THC, CBD, protein, starch, chlorophyll and several nutrients by weighted gene co-expression network analysis. This identified sets of genes and their hub genes underlying these expression / trait correlations as possible markers to improve cannabis cultivation and yield.

P10.6 A PANGENOME AND DIVERSITY PANEL FOR CANNABIS

Wednesday 5 July 2023 16:15

Marco Todesco (University of British Columbia, Canada), Mojtaba Jahani (University of British Columbia, Canada), Natalia Bercovich (University of British Columbia, Canada), José Miguel Lazaro-Guevara (University of British Columbia, Canada), Kaichi Huang (University of British Columbia, Canada), Soren Seifi (Aurora Cannabis Inc., Canada), Taylor O'Brian (Aurora Cannabis Inc., Canada), Pauline Duriez (University of British Columbia, Canada), José Celedon (Aurora Cannabis Inc., Canada), Charles Pick (Aurora Cannabis Inc., Canada), Greg Baute (Aurora Cannabis Inc., Canada) mtodesco@msl.ubc.ca

Despite its significant economic and medical value, cannabis (Cannabis sativa) still lags behind other major crops in terms of genetic and genomic resources. This has affected our understanding of genetic diversity within this species, and is a limiting factor in functional genomics efforts and in the development of genomics-enabled breeding pipelines.

To help fill this gap, we are generating a cannabis pangenome composed of 15 novel high-quality, haplotype-resolved, chromosomescale genome assemblies, for 12 drug-type lines and three hemp-type lines. We used a combination of high-coverage PacBio HiFi reads, chromosome conformation capture (Hi-C), and genetic maps to produce two complete haplotypes for each genotype. The size of these assemblies varies from 743 to 814 Mb, with BUSCO genome completeness scores of 95-98% and very limited duplication rates. For all the assemblies, more than 95% of the assembly was assigned to the first ten scaffolds (corresponding to the ten cannabis chromosomes).

In parallel to the generation of the cannabis pan-genome, we have also developed a cannabis diversity (CanD) panel by re-sequencing the genomes of 537 production and exotic drug-type cannabis lines. A proof-of-concept GWAS using the CanD panel identified several loci associated with resistance to the fungal pathogen powdery mildew. Together, the pan-genome and CanD panel provide a compendium of sequence and structural diversity in cannabis, and a valuable resource for plant genomics research and cannabis breeding.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

P10.7 UTILISING PLANT'S SECRET WEAPON; FUNCTION, STRUCTURE AND TRANSLATIONAL APPLICATIONS OF TERPENE SYNTHASES

Wednesday 5 July 2023 POSTER SESSION

Danielle Wiles (La Trobe University, Australia), Travis Beddoe (La Trobe University, Australia)

18917457@students.latrobe.edu.au

Natural products are increasingly being targeted as new antibiotic agents to overcome the severe threat posed to modern medicine by antimicrobial resistance. Terpenes comprise the largest group of phytochemicals that are widely distributed across all domains of life, with important and diverse biological roles. Terpenes are of tremendous economic value as fragrances, flavours, cosmetic and

pharmaceutical agents. However, there is also a growing body of evidence that terpenes elicit a broad range of medicinal properties which various effect on both humans and animals. Cannabis terpenes have emerged as a promising new target for antimicrobial and wound healing therapies. Despite the importance of terpenes there remains a number of unknowns about the enzymes that synthesise these molecules. Deepening our understanding of the terpene synthases allows us to uncover the mechanisms that underpin their formation and exploit their natural biosynthesis machinery to generate new variants of antimicrobial terpenes. Terpene synthase enzymes are the gatekeepers of the fascinating terpene assembly line, responsible forthe cyclisation of diphosphate substrates into the vast chemical library of terpene products. We are investigating these enzymatic systems using a combination of approaches (structural biology, biochemistry, enzymatic catalysis and protein engineering) in order to reengineer and produce new, more effective antibiotics, utilising these enzymes as biocatalysts. Furthermore, my research aims to discover more about the mechanism of action that allows terpenes to act against microbes and the extent to which they can do this.

P10.8 NUTRIENT PROFILING OF TWO CONTRASTING CHEMOTYPES OF CANNABIS SATIVA L.

Wednesday 5 July 2023 POSTER SESSION

Ricarda Jost (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Oliver Berkowitz (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Amelia Pegg (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Hannah Noorda (Cann Group Limited, Australia), Matthew T Welling (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Muluneh Oli (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Bhavna Hurgobin (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia), Filippa Brugliera (Cann Group Limited, Australia), James Whelan (ARC Research HUB for Medicinal Agriculture La Trobe University, Australia)

r.jost@latrobe.edu.au

While Cannabis sativa L. is one of our oldest cultivated crops, industrialscale medicinal agriculture is a relatively recent development coinciding with changes in regulatory frameworks for recreational and medical use of cannabis-derived products. Given the dioecious and heterogenous nature of popular medicinal cannabis cultivars, clonal material is often used for stable cannabinoid yield. However, individual cultivars still differ in their response to cultivation conditions. This is due to the fact that genotypes stem from different parts of the world, with frequent mixing of locally adapted wild populations and cultivars. It is therefore necessary to assess cultivar performance on both a physiological and molecular level. Information gathered can then be used to identify performance-limiting factors and cultivation requirements. Here, we set out to characterize the nutrient status and biomass allocation profiles of two genotypes contrasting in their cannabinoid profiles, one with high cannabidiol (CBD), and one with high tetrahydrocannabinol (THC) content. We will present detailed nutrient and key metabolite profiles, physiological and transcriptome data for different organs of the two genotypes at flower harvest.

SCIENCE ACROSS BOUNDARIES ABSTRACTS (ANIMAL, CELL AND PLANT BIOLOGY)

AC1 - THERMOREGULATORY AND METABOLIC ADAPTATIONS IN A CHANGING WORLD

ORGANISED BY: JÉRÉMY TERRIEN (NATURAL HISTORY NATIONAL MUSEUM), JULIA NOWACK (LIVERPOOL JOHN MOORES UNIVERSITY), SYLVAIN GIROUD (VETMEDUNI VIENNA & UNIVERSITY OF VIENNA)

POSTER SESSIONS

Wednesday 5 July 2023 17:15 - 19:15

AC1.1 TRACKING THERMOGENESIS AND METABOLIC SCALING THROUGHOUT DEVELOPMENT IN SMALL MAMMALS

Wednesday 5 July 2023 POSTER SESSION

Jessica L Li (University of British Columbia, Canada), Ryan J Sprenger (University of British Columbia, Canada), William K Milsom (University of British Columbia, Canada)

jessli@zoology.ubc.ca

Metabolic scaling describes the relationship between metabolic rate and body size, and can be calculated using the equation Metabolic Rate = a(Body Mass)B . Juvenile mammals have been reported to have higher exponent (B) values until they reach adult body size and experience a critical switch, after which B decreases and scaling becomes hypometric. Preliminary data indicate that altricial thirteen-lined ground squirrels (Ictidomys tridecemlineatus) experience their metabolic critical switch around the same time they start to develop the ability to endogenously thermoregulate. This study tracked changes in metabolic scaling through development, and how it correlated with the development of thermogenesis. Masses of I. tridecemlineatus pups and metabolic rates measured via whole body plethysmography were obtained over a wide range of developmental stages. Body temperatures and metabolic rates obtained from pups exposed to a cooling challenge were also compiled into a series of curves visualizing the development of coldinduced thermogenic responses. I. tridecemlineatus pups experienced their metabolic critical switch at 20-26 days of age, as their B value decreased from 1.20 to 0.76 (adj R2 =0.90, p p=2.70E-03; adj. R2 =0.67, p=2.84E-02). Breakpoint analysis revealed that pups achieved greater thermogenic capacity following 24 days of age. This occurred well before reaching adult size, indicating factors other than body size underly scaling during development. Funded by the NSERC of Canada.

AC1.2 MECHANISMS UNDERPINNING PHENOTYPIC PLASTICITY OF DESICCATION RESISTANCE IN CERATITIS SPECIES

Wednesday 5 July 2023 POSTER SESSION

Henrika J Bosua (Stellenbosch University, South Africa), Christopher W Weldon (University of Pretoria, South Africa), Marshall D McCue (Sable Systems International, United States), John S Terblanche (Stellenbosch University, South Africa)

henriekb@sun.ac.za

Closely related fruit fly species vary in geographic distributions with each species encountering a specific set of environmental conditions. This suggests that each species has underlying physiological traits that differ from others. We explored desiccation mechanisms in Ceratitis to determine if basal and/or plastic desiccation responses differ between broadly distributed (Ceratitis capitata) and narrowly distributed species (Ceratitis cosyra, Ceratitis podocarpi and Ceratitis rosa). The four species were acclimated with three temperature and humidity pre-treatments after which survival and different water loss traits were measured under dry conditions. Survival of C. capitata improved by 43% following both temperature and desiccation pre-treatments, while survival in the other species increased by 4-30% only after a desiccation pre-treatment. Ceratitis capitata showed more plasticity in several water loss traits, and small changes in activity, cuticular water loss and excretion after pre-treatments contributed to low water loss. Secondly, the role of metabolic water gain in desiccation physiology was studied by enriching body stores through larval diets with 13 C labelled stable isotopes (13 C-glucose, 13 C-leucine and 13 C-palmitic acid) in a desiccation resistant (Ceratitis capitata) and desiccation sensitive species (Ceratitis rosa). Differential mobilisation of 13 C-labelled body fuels during desiccation stress indicates that C. capitata was able to increase lipid oxidation both during and after desiccation while C. rosa mobilised lipids only after a desiccation event. Therefore, Ceratitis species rely on unique combinations of desiccation resistance strategies, and the species with the most flexible responses to stressful, fluctuating environmental conditions (C. capitata) derives the largest benefit.

AC1.3 INVESTIGATING THE USE OF HEART RATE BIOLOGGING TO QUANTIFY SPECIFIC DYNAMIC ACTION IN THE LEOPARD CORAL GROUPER

Wednesday 5 July 2023

POSTER SESSION

Jessica L Li (University of British Columbia, Canada), Ryan J Sprenger (University of British Columbia, Canada), William K Milsom (University of British Columbia, Canada)

l.kuchenmueller@deakin.edu.au

Animals must consume food to acquire the energy they need to survive. Global warming is forcing animals to adapt their food intake, both to satisfy changing energy demands and to maintain metabolic capacities. The metabolic response that accompanies meal digestion, absorption and assimilation is termed “specific dynamic action” (SDA). After feeding, a rapid increase in metabolic rate is typically followed by a slower return to baseline levels, and the magnitude and duration of the SDA response increase with meal size. Despite the usefulness of SDA in understanding food consumption and energy dynamics, measurements are restricted to laboratory conditions and therefore the ecological relevance of SDA cannot be completely realised. In this study, we test whether measurements of biologged heart rates can provide a useful proxy for the SDA response in 2 kg coral grouper (Plectropomus leopardus) fed meals of 50, 100, or 150 g of sardine (i.e., 3 to 9% body weight) at 26 and 30°C. We show that the impacts of meal size and temperature on the heart rate response are well-represented and may provide a good proxy for SDA. This presentation will expand on the implications of these findings, and discuss how fish might adapt to global climate change through food intake and consequential metabolic regulation. I will provide an outlook on implications for growth and highlight the potential of monitoring heart rates with biologgers to investigate temperature-dependent metabolic adaptations.

AC1.4 HETEROTHERMY CORRELATES WITH FITNESS OUTCOMES IN MAMMALS

Wednesday 5 July 2023

POSTER SESSION

Shane K Maloney (University of Western Australia, Australia), Dominique Blache (University of Western Australia, Australia), Dzulsahimi Daud (University of Western Australia, Australia), Peter R Kamerman (University of the Witwatersrand, South Africa), Andrea Fuller (University of the Witwatersrand, South Africa)

shane.maloney@uwa.edu.au

An increase in the amplitude of the 24-h rhythm of body temperature in mammals can be induced by energy and water deficits. Since performance traits also are impacted by energy and water, we investigated whether variability in the daily rhythm of body temperature can provide an indication of an individual’s investment in growth and reproduction. In the field, we measured the core body temperature of rabbits, alpacas, and buffalo for a year, and correlated the parameters of the circadian rhythm with the outcomes of number of pregnancies (rabbits) and growth (alpaca and buffalo). We used cosinor analysis to determine the average daily mean, minimum, and amplitude of core body temperature for each individual. In rabbits, individuals that

maintained the highest average daily minimum body temperature prior to the breeding season subsequently had more pregnancies than individuals that had lower average daily minimum body temperature. In alpacas and buffalos, changes in season and food availability led to variation in growth and in the amplitude of the daily rhythm of body temperature. Alpacas and buffalos that maintained the highest average daily minimum body temperature gained more body mass than those that had lower average daily minimum body temperature. The concentration of plasma leptin was significantly related to mass gain, but not to the rhythm of body temperature. We propose that the pattern of the 24-h body temperature rhythm could provide an index of animal fitness to a given environment.

AC1.5 THE THERMAL PERFORMANCE OF DIAPAUSE TERMINATION AND ITS ENERGY LIMITS, IN THE GREEN VEINED WHITE BUTTERFLY PIERIS NAPI

Wednesday 5 July 2023 POSTER SESSION

Philip Süess (Stockholms university, Sweden), Loke Von Schmalensee (Stockholms university, Sweden), Kevin T. Roberts (Stockholms university, Sweden), Philipp Lehmann (Universität Greifswald, Germany)

philip.suess@zoologi.su.se

Many insects in temperate environments undergo a resting stage, called diapause, in winter to avoid the adverse environmental conditions. The butterfly Pieris napi enters diapause as a pupa in early autumn and remains dormant until the following spring. To terminate the endogenous portion of diapause P. napi needs a prolonged period of cold temperatures. We can show that this diapause termination follows a thermal function with higher rates of termination at low temperatures. As soon as diapause is terminated, the insects return to development on a thermal performance curve with higher rates of development at high temperatures. Together, those two curves allow the insect to safely enter winter without any precocious development and enable the synchronization of emergence over a prolonged period. As pupal diapause is a prolonged period without the option of additional resource uptake, the pupae suppress the metabolic rate throughout diapause. We were able to show that this suppression is accompanied by the switch from continuous gas exchange to discontinuous gas exchange. The increase of metabolic rate in diapause at higher temperatures stems from the fact that the frequency of the discontinuous gas exchange cycle increased, while the amount of CO2 expelled in a single open phase remained steady at 0°C, 4°C and 20°C. The energy depletion due to the increased resource consumption as well as the lower termination rate at higher temperatures furthermore constitute the upper limit to the diapause termination thermal function and explains why none of the pupae emerge at high temperatures.

AC1.6 SYSTEMIC CHANGES IN CELL SIZE THROUGH THE BODY AND FLIGHT PERFORMANCE IN DROSOPHILA MELANOGASTER: LINKS TO RAPAMYCININDUCED TOR DOWNREGULATION

Wednesday 5 July 2023 POSTER SESSION

Ewa Szlachcic (Jagiellonian University in Kraków, Poland), Anna M. Labecka (Jagiellonian University in Kraków, Poland), Valeriya Privalova (Jagiellonian University in Kraków, Poland), Anna Sikorska (Jagiellonian University in Kraków, Poland), Marcin Czarnoleski (Jagiellonian University in Kraków, Poland)

ewa.szlachcic@doctoral.uj.edu.pl

Cellularity is an apparent feature of organisms on Earth. Cell size differs between populations and species, but it remains unclear whether these changes occur synchronically or independently in different cell types and whether they have fitness consequences. In two complementary studies, we reared genetic lines of Drosophila melanogaster on food with and without rapamycin to manipulate the activity of TOR/insulin pathways involved in cell cycle control and investigated the cellular composition of adult flies and their flight performance. Cell size was measured in five cell types: wing and leg epidermal cells, ommatidial cells, indirect flight muscle cells, and Malpighian tubule epithelial cells. Wing-beat frequency was measured in tethered males at two temperatures combined with two oxygen conditions. Rapamycintreated flies had smaller bodies and consistently smaller cells in all cell types. Regardless, females were larger with larger cells than males. Therefore, differences in TOR activity and sex were linked to the orchestration of cell size throughout the organism, leading to differences in body size. Flies generally flapped their wings more slowly under cooler and less-oxygenated conditions; however, small-celled flies showed no oxygen limitation under cooler conditions compared to large-celled flies. We use the theory of optimal cell size (TOCS) to discuss our results, addressing the adaptive value of cell size. We conclude that the cellular composition of organisms should be considered more often when investigating the organismal performance of ectotherms in the changing world and the origin of ecological and evolutionary patterns in life histories.

AC1.7

Wednesday 5 July 2023 POSTER SESSION

Shahar Dubiner (Tel Aviv University, Israel), Eran Levin (Tel Aviv University, Israel), Shai Meiri (Tel Aviv University, Israel)

dubiner@mail.tau.ac.il

Reptile activity is constrained by cold temperatures, so many reptiles cease activity during winter. During that period of hibernation there is little to no energetic intake, so there is an advantage to reversibly reducing energetic costs. One determinant of metabolic rate is the size of energetically costly internal organs, a trait known to be flexible in many tetrapod species. Therefore, seasonal plasticity of organ size can serve as both an energy-saving mechanism and a source of nutrients in hibernating reptiles. We studied the newly invasive population of

the geckoTarentola annularisand observed no activity between early December and early March. Standard metabolic rates mid-hibernation were lower than for active individuals. Following dissection of museum specimens, we found the heart, stomach, and liver decreased in mass during hibernation. The testes exhibited increased mass in winter until early spring, which is the breeding season. The kidneys and lungs did not change in size throughout the year. Atrophy of the organs that changed did not occur until after the geckos begin to hibernate, indicating that it happens primarily in response to (rather than in anticipation of) cold winter temperatures and the associated fasting. However, the testes grow in the time leading to winter and are maintained at full size until spring, representing a prioritization of breeding over other functions. Organ size plasticity can serve to adjust nutritional demands in times of low supply. These findings bring us closer to a mechanistic understanding of reptiles’ physiological adaptations to temperature shifts in the environment.

AC1.8 THE LINK BETWEEN INDIVIDUAL METABOLISM AND FORAGING BEHAVIOR DURING THE LIFE STAGE DEVELOPMENT

Wednesday 5 July 2023 POSTER SESSION

Sarah Boulamail (University of Salento, Italy), Sarah Boulamail (University of Salento, Italy), Milad SHOKRI SARAVI (University of Salento, Italy), Francesco Cozzoli (University of Salento, Italy), Shaun Killen (University of Glasgow, United Kingdom), Alberto Basset (University of Salento, Italy) sarah.boulamail@studenti.unisalento.it

Foraging behavior is a crucial fitness determinant over the course of an animal’s life. Foraging and energy needs are interdependent and covary at the individual level. Owing to thermal dependency of ectotherms’ energy needs, it is conceivable that their foraging behavior will be generally affected by global warming, and so the foragers' fitness. However, individual foragers often differ consistently in their behavior even within a single population (i.e., animal personality), which can constrain their responses to environmental variation.Here, we investigated the relationship between standard metabolic rate (SMR) and resource acquisition behavior of the amphipods Gammarus insensibilis,and of black molly fish Poeacilia sphenops (incorporating also the temperature effects) to provide a mechanistic explanation to the inter individual variation. The SMR was measured using a respirometry system and the behavioral patterns were conducted using automated video analysis in a patchy environment. Overall, results showed that the total number of visits to the resource patch ofG. insensibiliswere correlated positively with SMR (with a scaling exponent of 0.480), while it didn’t with body mass. Furthermore, preliminary results on behavioral patterns of black mollies, showed that temperature via its effect on SMR, exerted a major influence on their resource acquisition and exploratory behavior. Overall, our findings suggest that individual differences in energy requirements might be linked to consistent differences in foraging behavior. This finding has important implications for the understanding of the mechanisms underlying inter-individual commonalities and differences in behavior and responses to climate change.

SEASONAL SIZE CHANGES OF VISCERAL ORGANS IN AN INVASIVE DESERT GECKO

AC1.9 MECHANISTIC BASIS AND EVOLUTIONARY ASPECTS OF METABOLIC ALLOMETRY IN DAMSELFLIES AND DRAGONFLIES

Wednesday 5 July 2023

POSTER SESSION

Moa Metz (Norwegian University of Science and Technology, Norway), Daniel Schönberger (Lund University, Sweden), Andreas Nord (Lund University, Sweden), Erik Svensson (Lund University, Sweden)

metz.moa@gmail.com

Metabolic allometry is the study of how the minimal energy expenditure of an organism, standard metabolic rate (SMR), scales with the body mass. Previous research, predominantly on mammals and birds, typically finds allometric relationships between SMR and body mass, with a scaling coefficient (slope) of 0.75, often referred to as “Kleiber’s law“. This has been suggested to reflect some global physiological constraints. However, recently, it has been suggested that metabolic allometry instead results from life history optimization. Several recent studies on lower phylogenetic scales reveal scaling coefficients deviating from 0.75 and the intraspecific variation of metabolic allometry, along with its mechanistic basis, remains poorly understood. In this study, I aimed to investigate the variation in metabolic rate in an insect species, the common Bluetail Damselfly (Ischnura elegans). I measured SMR of individuals in three different temperatures and compared the sexes and three heritable female colour morphs that occur in this variable species. Furthermore, I compared the cell size of 20 species of Odonata (dragonflies and damselflies) to obtain a better understanding of possible physiological constraints on the evolution of SMR. In I. elegans, I found low intraspecific variation of metabolic allometry, allometric scaling coefficients that were generally lower than 0.75 and no evidence across species that SMR seemed to be directly constrained by cell size. My results are in line with recent theories that metabolic allometries probably have higher evolvabilities than previously thought.

AC1.10 GLOBAL ANALYSIS OF SQUAMATE BODY TEMPERATURES

Wednesday 5 July 2023 POSTER SESSION

Shahar Dubiner (Tel Aviv University, Israel), Eran Levin (Tel Aviv University, Israel), Shai Meiri (Tel Aviv University, Israel)

dubiner@mail.tau.ac.il

Squamate fitness is strongly linked to body temperatures (Tb ), which vary with environmental temperatures but can be regulated behaviourally by basking and seeking warm substrates. Attempts at synthesizing Tb across species and climates have used temperature means, measurements under laboratory conditions, or mathematically predicted values. A large-scale analysis of individual measurements in the field is lacking. We and 50 collaborators from 25 countries measured Tb and corresponding substrate and air temperatures (Tsub and Ta ) for ~15,000 individuals, representing 173 species belonging to 25 squamate families. Using phylogenetic analyses, we compared relationships between body and environmental temperatures (Tsub and Ta) , latitude and elevation, time of day and Julian date on squamates

that differ in their behaviour. We found that species that commonly bask have weaker relationship between Tb and environmental temperatures (higher intercepts, shallower slopes, less explained variance) than non heliotherm diurnal species and nocturnal species, except at high elevations and latitudes. Most species exhibit seasonal changes in Tb (beyond those predicted by environmental temperature) suggesting variations in thermoregulatory needs throughout the yearly cycle. Body temperature distributions of species become more left skewed as the species’ mean Tb increases, which may be due to the skewness of physiological performance curves, or due to activity nearer the critical thermal maxima. These field measurements, easily obtained in the field, hold potential for elucidating inter- and intraspecific patterns of thermoregulation and their consequences.

AC1.12 COLD AND HEAT WAVES JEOPARDIZE MECHANISMS UNDERLYING SHORT-TERM COORDINATION OF OXYGEN TRANSPORT CASCADE IN A NEOTROPICAL TELEOST, THE TRAHÍRA

Wednesday 5 July 2023

POSTER SESSION

Vinicius A Armelin (University of São Paulo (USP), Brazil), Igor N Guagnoni (São Paulo State University (UNESP), Brazil), Luiz H Florindo (São Paulo State University (UNESP), Brazil), Carlos A Navas (University of São Paulo (USP), Brazil) vinicius.armelin@gmail.com

Decades ago, it was postulated that thermal tolerance in fish was associated with their ability to sustain aerobic metabolism, and although some studies support this hypothesis, an increasing number of investigations fails to confirm it. Nevertheless, these earlier studies mainly evaluated raw cardiorespiratory variables in response to temperature changes without considering regulatory mechanisms underlying the coordination of the oxygen extraction and transport cascade (e.g., baro- and chemoreflex). We thus aimed to ascertain how acute changes in temperature influence the short-term regulation of oxygen management, intending to unravel a more sensitive thermal influence on physiological homeostasis capable of impairing fitnessrelated activities. To do so, we instrumented specimens of Hoplias malabaricus with ventral aortic and buccal cannulas, and placed them in an intermittent-flow respirometry system, in order to study their oxygen consumption, cardiorespiratory function and efficiency in meeting aerobic demands, and cardiorespiratory neurohumoral control (autonomic, baroreflex and chemoreflex function). All fish were acclimated at 25°C, and the data were collected from undisturbed animals kept at preferential temperature (25°C, N=7), or acutely submitted to non-preferential temperatures (15°C and 35°C, N=7 each) – under untreated condition, after muscarinic blockade with atropine (2 mg.kg-1 ) and after double autonomic blockade with atropine and propranolol (2 mg.kg-1 ). Our results demonstrates that the animals’ baro- and chemoreflex responsiveness were reduced at non-preferential temperatures, as well as ventilatory efficiency. The disruption of cardiorespiratory reflexes with atropine and propranolol generated a similar effect on ventilatory efficiency, suggesting that such events are intertwined. Funding: grant #2020/04335-0, São Paulo Research Foundation (FAPESP).

AC1.13 THE ENERGETIC TRADEOFFS OF ACCLIMATING TO THERMAL VARIABILITY IN TROPICAL AND TEMPERATE DUNG BEETLES

Wednesday 5 July 2023

POSTER SESSION

Alexander J Coverley (University of British Columbia, Canada), Morgan J Fleming (University of Tennessee, United States), Kimberley S Sheldon (University of Tennessee, United States), Katie E Marshall (University of British Columbia, Canada)

coverley@zoology.ubc.ca

Thermal variability varies across the globe, with generally higher variation in temperate regions than tropical regions. Thermal variability is energetically costly for ectotherms, as the rapid changes in body temperature can cause increased metabolic rate. Acclimation can modulate the relationship between temperature and metabolic rate, but the relationship between phenotypic plasticity and thermal variability is considerably understudied.

Temperate species are hypothesized to be more capable of mounting plastic responses to thermal variability as they are adapted to a broader range of temperatures. Here we test that hypothesis using a paired thermal variation experiment conducted in Tena, Ecuador (tropical), and Knoxville Tennessee (temperate), using three congeneric pairs of dung beetle species. In each location, we divided beetles into three groups and exposed them to either a constant temperature (22°C±2°C), low amplitude fluctuation (22°C±6°C), or high amplitude fluctuation (22°C±10°C). We predicted that temperate species would acclimate more to thermal variation than the tropical species, reducing their temperature sensitivity of metabolic rate and losing less lipid and glycogen during the acclimation than tropical species. Data analysis on metabolic rates and energetic reserves is ongoing. Dung beetles are morphologically diverse and exist on every continent and are necessary for maintaining ecosystem health and agriculture. Ascertaining acclimation capacity helps to predict the extent to which plastic responses to thermal variability shape species success under a changing climate.

AC1.14 ADAPTING TO CHANGING TEMPERATURES:

Wednesday 5 July 2023

POSTER SESSION

Caitlin McAndry (University of Plymouth, United Kingdom), Peter Cotton (University of Plymouth, United Kingdom), Enrico L. Rezende (Universidad Católica de Chile, Chile), Manuela Truebano (University of Plymouth, United Kingdom)

caitlin.mcandry@plymouth.ac.uk

Phenotypic plasticity can facilitate survival when organisms are faced with thermal challenges, potentially instigating change across multiple levels of organisation. Thermal performance curves (TPCs) represent a promising method for investigating the interactions, limits and trade-offs of plasticity across these levels, and how they may shift in organisms with different environmental histories. This study utilises the TPC framework to compare the plasticity of phenotypic traits from metabolism to whole-organism performance in the brackishwater

amphipod Gammarus chevreuxi, and how these are shifted when the organisms are acclimated to different temperatures (15°C or 20°C). We measured enzyme activity, metabolic rate, and swimming behaviour at multiple temperatures across the full thermal performance range for each trait. We then modelled TPCs, comparing how they changed at each level of organisation with acclimation treatment of the organisms. We present our findings on how thermal plasticity and thermal history interact across levels of organisation, and discuss how this understanding can help us predict organism and population-level responses to global change.

AC1.15 BEHAVIORAL THERMOREGULATION UNDER CHRONIC AND ACUTE HEAT STRESS IN INTERTIDAL NUDIBRANCHS

Wednesday 5 July 2023 POSTER SESSION

Lorena Munoz (Chapman University, United States), Madison Beltran (University of San Diego, United States), Eric J Armstrong (Université de Perpignan, France), Nicholas P Burnett (University of California at Davis, United States), Richelle L Tanner (Chapman University, United States)

lomunoz@chapman.edu

Scientists and amateur tidepoolers alike have noticed an anecdotal increase in nudibranch abundance and an expansion of their geographic distribution in California in recent warm years, but little is known about why and how nudibranchs are thriving in present conditions. Our previous work has shown that there is a physiological tradeoff between heat tolerance and the ability to rapidly increase heat tolerance through acclimation. These species coexist in the same tidepools, which led us to ask: are there behavioral mechanisms at play in microhabitat use that distinguish nudibranch species’ thermal tolerance (i.e., do some nudibranchs seek thermal refuge and other use biochemical strategies to mitigate heat stress)? We collected intertidal nudibranchs from sites across Southern California to characterize their thermoregulatory behavior in the context of climate change-induced warming and extreme heat days. Nudibranchs were acclimated to cool and warm temperatures for two weeks and subsequently placed in simulated hot and cold tidepools for two days, representing chronic and acute heat stress. Nudibranchs in the warmer chronic acclimation temperatures were more likely to engage in escape behaviors (i.e., floating on surface tension) but nudibranchs in the acutely hot tidepools were less active and less likely to float than in cool tidepools. Because nudibranchs are more abundant during warm periods, understanding the interplay between physiology and behavior for nudibranch species may serve as an indicator of intertidal community health under climate change scenarios.

AC1.16 CONSEQUENCES OF INCREASING TEMPERATURE ON BUMBLEBEE THERMOREGULATION DURING DIFFERENT BEHAVIORS

Wednesday 5 July 2023 POSTER SESSION

MULTI-LEVEL PHENOTYPIC PLASTICITY MEASURED WITH THERMAL PERFORMANCE CURVES.

Guadalupe Sepulveda (Department of Zoology Stockholm University, Sweden), Kevin T Roberts (Department of Zoology Stockholm University, Sweden), Priscila De Cássia Souza Araújo (Department of Zoology Stockholm University, Sweden), Philipp Lehmann (Department of Animal Physiology Zoological Institute and Museum University of Greifswald, Germany), Emily Baird (Department of Zoology Stockholm University, Sweden)

guadalupe.sepulveda@zoologi.su.se

Over the past decades increasing environmental temperature has been identified as one of the causes of major population decline and biodiversity loss, especially in ectothermic animals such as in insects. Among flying insects, bumblebees are generally capable of regulating body temperature and are considered endoheterothermic. However, because they evolved in temperate and cold conditions, they might lack the necessary thermoregulatory mechanisms needed to withstand rapid increases in environmental temperature. To investigate this, we measured tagma (head, thorax, and abdomen) temperature of bumblebee (Bombus terrestris) workers across a range of temperatures (24 °C to 32 °C) during three distinct behaviors (resting, pre-flight, and post-flight). We found that in resting bumblebees, the head and abdomen temperature conformed to the environmental temperature, but the thorax was significantly warmer. In pre-flight bumblebees, the head and abdomen were warmer than the environment but the thorax temperature was maintained constant, indicating a pre-flight warming stage. In post-flight bumblebees, abdomen temperature increased isometrically with environmental temperature but the head and the thorax temperature did not. By calculating the excess temperature ratio, we also show that thermoregulation in bumblebees during flight is partially achieved by the active transfer of heat produced in the thorax to the head and the abdomen, where it can more easily be dissipated. We conclude that thermoregulation in B. terrestris workers appears to be plastic and behavior-dependent

AC1.17 LET’S HUDDLE! ENERGY SAVINGS AND SOCIAL THERMOREGULATION

Thursday 6 July 2023 09:00

Caroline Gilbert (Caroline Gilbert, France), Dominic McCafferty (Scottish Centre for Ecology and the Natural Environment University of Glasgow Glasgow, United Kingdom), Christophe Guinet (UMR 7372 Centre d’études Biologiques de Chizé Chizé, France), Sylvain Giroud (Research Institute of Wildlife Ecology Department of Interdisciplinary Life Sciences University of, Austria), André Ancel (Department of Ecology Physiology

Ethology Pluridisciplinary Institute Hubert Curien UMR 7179, France)

caroline.gilbert@vet-alfort.fr

Among energy saving strategies, huddling can be defined as “an active and close aggregation of animals”, responding to unfavourable environmental conditions. Huddling allows endotherms to maximise energy savings by reducing individual heat loss and hence metabolic heat production to maintain a constant body temperature. This is a widely used energy saving strategy, encountered almost as often in mammals and birds than hypometabolic and hypothermic states that are daily torpor and hibernation. Depending on species, individuals of all ages may use it: newborn individuals, juveniles or adults. Unlike

torpor, huddling permits individuals to stay active and keep euthermic levels, but implies other constraints. Surprisingly, a few species can use both strategies.

As a short review, we will explore the ecological factors influencing huddling and the energetic benefits associated to this energy conservation strategy, with a focus on key species known to face contrasted environmental conditions: emperor penguins, newborn rabbits (Oryctolagus cuniculus), elephant seals (Mirounga leonina), and garden dormice (Eliomys quercinus).

AC1.18 CONTEXT-DEPENDENT RELATIONSHIPS BETWEEN SURFACE, SUBCUTANEOUS AND CORE BODY TEMPERATURES IN ADÉLIE PENGUINS DURING BREEDING SEASON

Thursday 6 July 2023 09:30

Agnès Lewden (IUEM, France), Thierry Raclot (IPHC - DEPE, France), Frédéric Angelier (CEBC - CNRS Chizé, France), Yan Ropert-Coudert (CEBC - CNRS Chizé, France), Akiko Kato (CEBC - CNRS Chizé, France), Antoine Stier (IPHC - DEPE University of Turku University of Lyon, France)

caroline.gilbert@vet-alfort.fr

Antarctic penguins spend the major part of their life in cold water and maintain a high body temperature despite facing high heat loss. During short but crucial parts of their life, penguins come back ashore to breed, ensuring population renewal. With ambient temperature predicted to increase by 2°C in Antarctica by 2050, penguins must now cope with warmer terrestrial environments but we know relatively little about their thermal biology on land.

Studying thermal biology in wild and protected animals is challenging and minimally-invasive (but biologically informative) methods are needed. Infrared thermography is a non-invasive technology widely used recent years to measure animal body surface in response to environmental factors. However, diving birds can show a large gradient of temperature between periphery and internal tissues, allowing them to minimize heat loss. Thus, in these large species, the biological relevance of surface body temperature is unknown.

To better understand the relationship between surface, peripheral and core body temperatures, we equipped free-living Adélie penguins (Pygoscelis adeliae) during reproduction with thermo-sensitive subcutaneous pit-tags and ingestible temperature loggers, and we took thermal images. The data collected has been analyzed along with weather data to model how the relationships between surface, peripheral and core body temperatures covary across a gradient of environmental conditions. We predict that under mild environmental conditions the three temperatures will be strongly correlated, whereas under harsh conditions (cold or warm), surface temperature will reflect more peripheral than core body temperature.

AC1.19 EFFECT OF SEASON, ENVIRONMENTAL VARIATION, AND REPRODUCTION ON THERMOREGULATION IN AN ARCTIC UNGULATE

Thursday 6 July 2023 09:45

Liv Monica Trondrud (Norwegian University of Life Sciences, Norway), Leif Egil Loe (Norwegian University of Life Sciences, Norway), Gabriel Pigeon (Université du Québec en AbitibiTémiscamingue, Canada), Steve Albon (James Hutton Institute, United Kingdom), Walter Arnold (University of Veterinary Medicine, Austria), Erik Ropstad (Norwegian University of Life Sciences, Norway), Elzbieta Kròl (University of Aberdeen, United Kingdom)

monica.trondrud@nmbu.no

Seasonal environments can impose strong and temporally varying energetic challenges on endotherms. The role of thermal responses to these energetic challenges has been shown to be important even among endotherms which traditionally have been considered “normothermic”, such as ungulates. Because thermoregulation can be an energetically costly process, thermal responses to environmental fluctuations and their energetic benefits can potentially improve individual fitness. However, quantification of these thermal responses in free-living animals require the use of biologging devices, and their placement and temporal resolution may themselves impact how thermoregulatory responses are interpreted. Here, we will present body temperature (Tb) patterns in a high-Arctic ungulate, the Svalbard reindeer (Rangifer tarandus platyrhynchus), collected across three years and from three different biologging devices in different placements on the body, to illustrate the challenges of quantifying thermoregulatory responses in large mammals. We report both within-and between individual variation in body temperature patterns across seasons, years, and logger placements. We show that Tb variation is more pronounced in winter than in summer, and during winter it is greater at lower ambient temperatures. Further, we show that pregnant females remain less vary less in their Tb at low ambient temperatures compared to nonpregnant females. Lastly, we demonstrate that peripheral Tb recorded from different locations on the body do not always capture the same thermoregulatory responses to environmental variation. Our study contributes to the increasing amount of literature on heterothermy in large, non-hibernating endotherms and highlight the importance of evaluating thermal responses in the relevant ecological and physiological context.

linda.adzigbli@uni-rostock.de

Marine environments are characterized by consistent oxygen fluctuations and limitations (Hypoxia). Hypoxia has major impacts on energy metabolism and for marine organisms inhabiting hypoxic-prone zones, this is a major problem. Hypoxia interrupts energy production and availability and also exposes organisms to oxidative stress and damage. Mitochondria are known key players in energy homeostasis hence during hypoxia, they become the major targets. H/R stress disrupts the electron transport system and alters the intracellular concentrations of metabolic fuels leading to the depletion of carbohydrates, accumulation of succinate and acetate, and a shift in the relative concentrations of different amino acids. These changes might affect the availability of mitochondrial substrates and have major implications for bioenergetics and redox balance. Nonetheless, some marine bivalves (those inhabiting the benthic and intertidal zones) have developed some adaptations to hypoxic stress. One such adaptation is the metabolic flexibility in mitochondrial substrate utilization under H/R stress. In our study, we studied the mitochondria flexibility of marine organisms (Crassostrea gigasandPecten maximus) with different hypoxia sensitivities in utilizing mitochondrial substrate under different hypoxic conditions and evaluated their substrate-specific stress responses. We observed that succinate oxidation under H/R stress heightens mitochondrial functional activity while reducing the negative effects. However, this was restrictive to hypoxia-tolerant organisms. Under H/R stress, the hypoxia-tolerant pacific oysterC. gigasincreased energy generation through oxidative phosphorylation while maintaining ROS production while the hypoxia-sensitive scallopP. maximusdecreased energy production while maintaining ROS. Our result provides insight into some mechanisms of hypoxia adaptation in marine organisms.

AC1.22 CAN MAMMALS STAY AHEAD OF GLOBAL HEATING IN A CHANGING WORLD?

Thursday 6 July 2023 11:00

Andrea Fuller (University of the Witwatersrand, South Africa), Edward Snelling (University of Pretoria, South Africa), Shane Maloney (University of Western Australia, Australia), Duncan Mitchell (University of the Witwatersrand, South Africa)

Thursday 6 July 2023 10:15

andrea.fuller@wits.ac.za

Understanding how heat is exchanged between a terrestrial mammal and its environment is essential for accurate predictive modelling of mammalian responses to climate change. Almost all models predicting how the function, range and abundance of mammals will change with global heating use air temperature as the index of heating. However, the complex thermal environment of free-living mammals cannot be quantified by air temperature alone, and in hot environments air temperature is not an important index of heat loss or gain. No thermal

Linda Adzigbli (Research Institute for Farm Animal Biology (FBN), Germany), Eugene P. Sokolov (Leibniz Institute for Baltic Sea Research Leibniz Science Campus Phosphorus Research Warnemünde, Germany), Siriluck Ponsuksili (Research Institute for Farm Animal Biology (FBN) Institute of Genome Biology Dummerstorf, Germany), Klaus Wimmers (Research Institute for Farm Animal Biology (FBN) Institute of Genome Biology Dummerstorf, Germany), Inna Sokolova (Department of Marine Biology Institute for Biological Sciences University of Rostock Rostock, Germany)

AC1.21 SUCCINATE: A POTENTIAL STRESS FUEL FOR MARINE ORGANISMS DURING HYPOXIA STRESS.

index will delineate fully what the range of environments will be with which a particular mammalian species will cope. That range will differ not only with food and water availability but also with factors that influence energy and water expenditure, such as pregnancy and lactation, activity level, illness and acclimatisation, as well as with body size. We show how long-term studies of representative species of free-living mammals in their natural environments, including physiological and behavioural measures, are needed for us to obtain a better grasp of whether mammals can stay ahead of global heating.

AC1.23 ADAPTATIVE VARIATION IN AVIAN BODY TEMPERATURE

Thursday 6 July 2023 11:30

Andrew E. McKechnie (University of Pretoria, South Africa), Marc T. Freeman (University of Pretoria, South Africa) aemckechnie@gmail.com

Early work on endotherm thermal physiology led pioneering researchers such as Per Scholander and his colleagues to conclude that body temperature (Tb ) is a non-adaptive constant. As a result, over the last seven decades hypotheses about endotherm physiological adaptation to climate have focused largely on traits such as metabolic rates and evaporative water loss, rather than Tb . We hypothesized that maximum Tb (Tb max) during heat exposure evolves in response to climate and tested this hypothesis using data for 56 bird species occupying three climatically distinct sites across southern Africa. Our results revealed significant among-site variation in Tb max as well as normothermic Tb (Tb norm), with comparatively high Tb max (45.60 ± 0.58 °C) and low Tb norm among birds occupying humid lowlands. Humid lowland species possessed a significantly greater capacity for hyperthermia (Tb max - Tb norm = 5.84 ± 0.77 °C) compared with birds occupying cool montane (4.97 ± 0.99 °C) or hot arid (4.11 ± 0.84 °C) climates. To evaluate the functional role of pronounced hyperthermia tolerance among humid lowland species, we quantified the effect of humidity of 19.2 g H2 O m− 3 on thermoregulation at environmental temperatures exceeding Tb norm among 30 species from the three study sites. These data revealed the functional role of pronounced hyperthermia is primarily related to maintaining physiological performance under conditions of high humidity. The notion of a continuum from thermal generalization to specialization among endotherms is strongly supported by observed patterns of physiological adaptation among our study species.

Survival and reproduction of endotherms depend on their ability to balance energy and water exchange with their environment, avoiding lethal deficits and maximising gains for growth and reproduction. Balancing energy and water exchanges is a particularly challenging process for species inhabiting hot, arid systems where they operate close to their thermal limits. Thus, accurate models of thermoregulatory processes are crucial for predicting the effects of climate variability on endotherms such as birds. Here, we evaluated the performance of a biophysical model (NicheMapR) for predicting thermoregulatory responses including changes in evaporative water loss, body temperature and resting metabolic rate in desert birds. Thereafter, we combined this biophysical model with behavioural data and climate change projections to predict desert birds’ thermal vulnerabilities and the associated physiological costs. We demonstrated that biophysical models can accurate predict thermoregulation, particularly at air temperature between 30 and 40 °C, a range spanning threshold values for sublethal fitness costs in arid-zone birds. Further, our model revealed an increased risk of lethal dehydration, in the absence of drinking, and hyperthermia under future climate change scenarios. Overall, our analysis revealed that biophysical models can provide critical insight into birds’ thermal limitations and the risk of population collapse in desert birds in coming decades.

AC1.25 SOLAR RADIATION, HUMIDITY AND CLIMATE CHANGE

Thursday 6 July 2023 12:00

Duncan Mitchell (University of the Witwatersrand, South Africa), Shane K Maloney (University of Western Australia, Australia), Edward Snelling (University of Pretoria, South Africa), Andrea Fuller (University of the Witwatersrand, South Africa)

duncanmitch@gmail.com

Thursday 6 July 2023 11:45

Shannon R Conradie (University of Cape Town, South Africa), Michael R Kearney (The University of Melbourne, Australia), Blair O Wolf (University of New Mexico, United States), Susan J Cunningham (University of Cape Town, South Africa), Marc T Freeman (University of Pretoria, South Africa), Ryno Kemp (University of Pretoria, South Africa), Andrew E McKechnie (University of Pretoria, South Africa)

shannonconradie@gmail.com

Changes in surface temperature under climate change predict sea level rise and heat wave risk, but not responses of animals to altered thermal environments. Local air temperature plays a minor role in heat stress on terrestrial animals outdoors, so the conventional practice of projecting responses from future air temperature is inadequate. Solar radiation, direct and indirect, is the main source of heat stress, and will be under climate change too. The calculation of radiant heat load from ambient radiant flux is possible, although difficult. Black globe thermometers provide a simple alternative to assess radiant heat load, and have been used successfully to predict heat stress across a wide range of animal taxa in their natural environments. Miniature globes, carried by animals themselves, provide an index of dry heat stress in the microclimate selected. Diurnally active animals can escape solar radiation by switching to nocturnal activity, or by burrowing, but to only a limited extent by seeking shade; all those behaviours incur costs. Animals that sweat or pant have the capacity to dissipate all the heat load expected under global warming, even with metabolic heat load increased by exercise, but the body water evaporated has to be replaced. Evaporative cooling depends on skin temperature, ambient water vapour pressure, and local wind speed. We recommend that globe thermometry should become routine in studies of animal responses to global warming, and that those studies should report surface wind speeds, and water vapour pressures, not relative humidity.

AC1.24 USING BIOPHYSICAL MODELS TO UNDERSTAND AND PREDICT DESERT BIRDS’ THERMAL VULNERABILITIES.

AC1.26 HEATING PEOPLE LYING DOWN –WHAT HAPPENS AT THE UPPER LIMIT OF THE HUMAN THERMONEUTRAL ZONE?

Thursday 6 July 2023 12:15

l.halsey@roehampton.ac.uk

As with other endothermic animals, for humans there is a range of ambient temperatures at which our resting metabolic rate (MR) is at a minimum - the thermoneutral zone (TNZ). While the TNZ lower limit for humans has been characterised, remarkably it is still unclear whether there is an upper limit to the human TNZ i.e. beyond which MR during rest increases; and if so, what physiological upregulations explain it. We measured 13 participants who rested while exposed for an hour to 28°C-50% relative humidity (RH) air (baseline), and both 40 and 50°C each in 25% RH and humid (50% RH) conditions. We recorded MR, core and skin temperatures, blood pressure, sweat-, heart-, and breathing-rate, minute ventilation and ‘fidgeting’ levels, throughout each condition. MR increased a remarkable 35% during exposure to just 40°C-25% RH compared to baseline and a further 13% at 50°C-50%RH. This was not explained by increased fidgeting in the heat, leaving only the possibility of physiological upregulation. However, while greater heat stress invoked increases in heart rate (64%), minute ventilation (78%) and sweat rate (74%) when comparing 50℃-50% RH with baseline, the likely energy costs of all this surely cannot explain the magnitude of increase in MR. Our study shows clear evidence that resting MR increases in people at high temperatures - there is an upper limit to the human TNZ, at least as low as 40°C. But what explains this upregulation? We don’t yet know (any ideas??).

AC1.27 TOADS ON ICE: PHYSIOLOGICAL

RESPONSES TO CHANGING WINTER CLIMATE IN AMPHIBIANS

Thursday 6 July 2023 14:30

Katharina Ruthsatz (Technical University of Braunschweig, Germany), Kathrin H. Dausmann (University of Hamburg, Germany), Joana Sabino-Pinto (University of Groningen, Netherlands), Robin Schmidt (Technical University of Braunschweig, Germany)

katharinaruthsatz@gmail.com

Climate change is rapidly modifying winter conditions with important ecological consequences. In a wide range of organisms including early spring breeding amphibians, phenological shifts have been attributed to changing winter climate. As a consequence, amphibians might face higher metabolic costs due to longer activity periods and are at risk of being exposed to late spring freezes. Here, we investigated the physiological responses to warmer winters and spring freeze in the common toad (Bufo bufo). To simulate warmer winters and spring freeze, toads were acclimated to 4°C or 8°C for 48h, or exposed to either 4°C or -2°C for 6h, respectively. We measured standard metabolic rate to assess the daily energy demands and determined body condition in toads acclimated to different winter temperatures. To explore the molecular responses to freezing, we used a transcriptome-level investigation of the hepatic and muscular tissue, and measured blood glucose level. Toads acclimated to higher temperatures revealed a

higher daily energy demand suggesting a faster decrease in energy budgets during warmer winters. Blood sugar levels were higher in frozen toads indicating the mobilization of cryoprotective glucose with the beginning of freezing. Gene expression analysis revealed changed patterns in genes related to cellular metabolism. Together, our results demonstrate that amphibians have strategies to cope with the challenges of changing winter climate to some extent, but also emphasize that warmer winters as well as repeated freeze-thaw cycles incur physiological costs that result in reduced energy reserves and might therefore pose a serious threat to breeding adults.

AC1.28 VULNERABILITY OF THE WORLD’S AMPHIBIANS TO GLOBAL WARMING

Thursday 6 July 2023 15:00

Patrice Pottier (The University of New South Wales, Australia), Julie E. Rej (Tulane University, United States), Alex R. Gunderson (Tulane University, United States), Michael R. Kearney (The University of Melbourne, Australia), Nicholas C. Wu (Western Sydney University, Australia), Samantha Burke (The University of New South Wales, Australia), Szymon M. Drobniak (The University of New South Wales, Australia), Shinichi Nakagawa (The University of New South Wales, Australia)

p.pottier@unsw.edu.au

Global warming is an accelerating threat to ectothermic species such as amphibians. However, the extent to which temperature extremes may exceed the physiological tolerance of amphibians has not been assessed at a global scale. Importantly, while physiological tolerance data has been widely collected, many species and areas of the world remain unsampled. Here, we developed new data imputation procedures to infer the heat tolerance of data-deficient amphibian species. We then used biophysical models to estimate the current and future body temperatures of 3000 amphibian species across their distribution range. We also specifically assessed the importance of thermoregulatory behaviours and microhabitat selection in buffering temperature extremes. By integrating physiological tolerance data with daily climatic exposure in protected environments, we established the largest assessment of the vulnerability of amphibians to temperature extremes. Our study effectively overcame taxonomical and geographical biases, and our findings will help identify the communities most vulnerable to temperature extremes and inform global conservation efforts.

AC1.29 VARIATION IN WINTER ENERGY

USE IS DETERMINED BY ALTERING A CRITICAL TRANSITION PERIOD IN DIAPAUSING PIERIS

Thursday 6 July 2023 15:15

Kevin T Roberts (Stockholm University, Sweden), Philip Süess (Stockholm University, Sweden), Philipp Lehmann (University of Greifswald, Germany)

kevin.roberts@zoologi.su.s

Lewis Halsey (University of Roehampton, United Kingdom)

Long winters in seasonal environments present massive energetic challenges for organisms. To survive winter, it is essential to manage resources, by both conserving stores and by synchronizing timing to maximize available resources in spring. The level of energetic suppression and timing of termination of dormancy is dependent on local winter conditions, which leads to local adaptation in winter phenotypes. Insects regulate winter energy use by entering diapause, a programmed dormancy, associated with halted development and suppressed metabolic rate. Diapause generally terminates mid-winter and is followed by a quiescent state allowing insects to exit dormancy if conditions become favorable. Locally adapted populations can fine tune energetic savings by altering either the extent of energy use in winter or by altering the timing of the transition to post-diapause quiescence. We currently do not have a good understanding of how locally adapted populations alter these processes to determine energetic savings in winter. Here, we measured metabolic rate-temperature relationships and diapause termination timing of four populations of the butterfly Pieris napi from across a latitudinal cline spanning Sweden. We found that metabolic rate-temperature relationships do not differ between populations during diapause, but they do increase after the transition from diapause to quiescence. We also found that diapause termination rate is delayed in northern populations that experience colder winters. Together this suggests that local adaptation of energy regulation in diapause is likely achieved through the modification of the timing of regulatory transition periods and not through modification of the thermal sensitivity of underlying metabolic mechanisms.

AC1.30 EXTREME METABOLIC DEPRESSION IN A DIAPAUSE REQUIRES A TEMPERATURE-SENSITIVE PREPARATORY PERIOD

Thursday 6 July 2023 15:30

Katie E Marshall (University of British Columbia, Canada), Ashlyn Wardlaw (Great Lakes Forestry Centre, Canada), Skye J Butterson (University of British Columbia, Canada), Amanda D Roe (Great Lakes Forestry Centre, Canada)

kmarshall@zoology.ubc.ca

Most insects in temperate, boreal, and Arctic ecosystems overwinter in a state of extreme metabolic suppression called diapause. In this state, feeding and development cease, and metabolic rate is significantly depressed. As insects are ectotherms, high temperatures during this period lead to high metabolic rates, leading to the risk of starvation as energy reserves cannot be replenished until spring. One of the strange aspects of diapause is that it is usually induced as much as two months before the onset of winter, while temperatures are still relatively warm. Modelling studies have indicated that this pre-winter period usually accounts for the majority of energy reserve depletion and that warming falls are having significant impacts on insect fitness. Why then do insects go into diapause so early? To answer this question, we subjected the eastern spruce budworm Choristoneura fumiferana to a series of temperatures between 10 and 25 °C for differing periods of time between 1 and 10 weeks in a fully-factorial experiment conducted during the second instar early diapause. As we expected, longer and warmer fall conditions led to significant energy drain, leaving the larvae with relatively little energy reserves to survive the winter. But quite unexpectedly, survival to spring emergence was highest in intermediate conditions. Cool, short falls, and long warm falls both

caused almost 100% mortality, but survival was highest following long cool falls and short warm falls. Taken together, we believe this indicates that there is a temperature-sensitive process in the fall that must complete for overwintering survival.

AC1.31 METABOLIC THERMAL SENSITIVITY OF OVERWINTERING MOUNTAIN PINE BEETLE LARVAE

Thursday 6 July 2023 15:45

Serita Fudlosid (Carleton University, Canada), Mads Andersen (Carleton University, Canada), Fouzia Haider (Carleton University, Canada), Amanda Roe (Natural Resources Canada, Canada), Antonia Musso (University of Alberta, Canada), Maya Evenden (University of Alberta, Canada), Caroline Williams (University of California Berkeley, United States), Heath A MacMillan (Carleton University, Canada) seritafudlosid@cmail.carleton.ca

Mountain pine beetle (MPB, Dendroctonus ponderosae) are an eruptive native bark beetle from western North America that have been steadily expanding eastward from their native range. These beetles are a major pest to pine trees causing extensive damage to forests and millions of dollars in losses to the forestry industry. One of the key factors preventing their expansion is the occurrence of prolonged extreme winter temperature. MPB larvae enter a non-feeding diapausing state during the winter, where conservation of energy stores is likely integral to survival. As winters become warmer and more thermallyvariable, understanding whether/how mountain pine beetles suppress their metabolism for survival during these winter months is crucial to mitigating and predicting their spread. We explored how metabolic rate changes seasonally and in response to temperature by measuring CO2 production during late fall, early winter, and late winter using stopflow respirometry at temperatures as low as -20°C. Metabolic rates of MPB larvae are highly temperature sensitive, but are similar and have similar thermal sensitivity over the winter season. This data can help us understand the changing metabolic profile of MPB larvae over winter periods to ultimately aid in providing a better understanding of their climate-driven range expansion.

AC1.32 USING BIOPHYSICAL MODELS TO PREDICT HOW HABITAT LOSS MAY RENDER THE ABILITY OF ANIMALS TO COPE WITH CLIMATE CHANGE

Thursday 6 July 2023 16:30

Ofir Levy (School of Zoology Faculty of Life Sciences

Tel Aviv University, Israel), Gavin Stark (School of Zoology Faculty of Life Sciences Tel Aviv University, Israel), Ma Liang (Sun Yat-sen University: Shenzhen Guangdong, China), Zhi-Gao Zeng (Sun Yat-sen University: Shenzhen Guangdong, China), Wei-Guo Du (Sun Yat-sen University: Shenzhen Guangdong, China)

levyofi@gmail.com

As habitat loss and climate change threaten global biodiversity, we need a theoretical framework for predicting the combined impacts of these two threats on the performance of organisms. However, current models simplify microhabitats' diversity of natural landscapes and are prone to biased predictions. By combining empirical and modeling approaches, we show the cascading effect of habitat loss and climate change on activity time and thermoregulatory accuracy in a diurnal desert lizard. Our model predicted a severe loss of summer activity in the absence of medium and large rocks. Future warming will gradually decrease summer activity as even large rocks become thermally stressful. Warmer winters will enable more activity and require bushes and small rocks as shade retreats. Hence, microhabitats that may seem unimportant today may become important under climate change. Such modeling frameworks may be crucial to understanding species’ microhabitat requirements and developing conservation programs.

AC1.33 ECOPHYSIOLOGY OF A SMALL ECTOTHERM TRACKS ENVIRONMENTAL VARIATION ALONG AN ELEVATIONAL CLINE

Thursday 6 July 2023 17:00

Rodolfo O Anderson (The University of Adelaide, Australia), Lesley Alton (Monash University, Australia), Craig White (Monash University, Australia), David Chapple (Monash University, Australia)

rco.anderson@gmail.com

Physiological responses to climate can be used to quantify the environmental limits that a species can tolerate and are, therefore, key to biogeographical studies. Several ecophysiological responses to climatic factors may shape the distribution of species, but our knowledge is mostly centred on thermal ecophysiology. We applied an integrative approach to investigate how ecophysiological responses of a small ectotherm are modulated by climatic variation across an elevational gradient. We examined metabolic rate, evaporative water loss, thermal physiology, and locomotor performance, of four populations of the skink Lampropholis guichenoti across an elevational gradient in Australia (17 to 1546 m). We applied biophysical modelling to test how behaviour impacts the survival and activity of these skinks. We found that populations from the lowlands had lower metabolic rates and evaporative water loss, lower thermal preferences, higher optimal temperatures and increased locomotor performance compared to that of populations from high elevations. Biophysical models revealed that behaviour allows skinks from high elevations to maintain their body temperatures above freezing and is key to determining activity patterns. Overall, our holistic study shows that a combination of physiological and behavioural responses allows ectotherms to survive in different climatic environments. The interplay between physiology and behaviour can help to explain how climate sets limits for the geographic range of ectotherms.

AC1.34 THERMAL LIMITATIONS OF THE SCORPION, PARUROCTONUS

ON ITS DISTRIBUTION.

Thursday 6 July 2023 17:15

Abraham L Miller (University of Tampa, United States), Emilie Gray (Ithaca College, United States)

abraham.miller@ut.edu

Global warming poses a threat to species survival. The scorpion Paruroctonus boreus has the highest latitudinal and elevational distribution of any scorpion in North America. It is unknown if P. boreus will tolerate the thermal effects of global warming or if it will need to shift its distribution. To begin to address this, our research investigated physiological performance of scorpions under three biologically relevant temperatures. Sprint times were recorded for runs at 12 ° C, 22 ° C and 30 ° C. Scorpions were significantly slower at 12 ° C compared to the two other temperatures, which did not differ from each other. Low temperature sensitivity was also assessed, by placing scorpions in a freezer (-18 ° C) for 10, 20 or 30 min and measuring the time it took them to right themselves after being flipped over. On average, it took scorpions 32, 161 and 247 sec to flip over after the 10, 20 or 30 min treatments respectively. Finally, upper critical temperature (CTmax) was tested using a thermally controlled flow through respirometer. The average CTmax was 53 ° C, but the rate of CO2 production rose significantly beyond 40 ° C. These results suggest P. boreus displays decreasing phenotypic plasticity above 22 ° C and cannot survive long beyond 40 ° C. As thermal conditions shift and become increasingly variable, populations may be forced to higher elevations, further restricting gene flow and threatening long term persistence.

Thursday 6 July 2023 17:30

Trevor E Pitcher (University of Windsor, Canada), Andy Turko (Wilfred Laurier University, Canada), Matthew Thorstensen (University of Manitoba, Canada), Ken Jeffries (University of Manitoba, Canada), Daniel Heath (University of Windsor, Canada)

tpitcher@uwindsor.ca

A variety of factors (e.g. climate change, urbanization) are leading to increases in water temperatures in streams and rivers and is hypothesized to be contributing to declines of many freshwater fishes. However, factors that influence individual variation in thermal tolerance, and how these may change seasonally and how they are controlled mechanistically, are not well understood. To address this knowledge gap, we studied redside daceClinostomus elongatus, an imperilled stream fish native to rapidly urbanizing areas of eastern North America. We conducted field studies to examine thermal tolerance (using CTMax) in the wild, used laboratory studies to experimentally manipulate individual condition and employed transcriptomics to

BOREUS, AND POTENTIAL IMPACTS

AC1.35 THERMAL TOLERANCE AS IT RELATES TO SEASON, BODY CONDITION AND GENE EXPRESSION IN IMPERILLED REDSIDE DACE, CLINOSTOMUS ELONGATUS.

provide a mechanistic understanding of an organism’s response to increasing temperatures. We found that (1) thermal safety margins (CTmax − ambient water temperature) were less than the increases in peak water temperature predicted for many streams due to the combined effects of climate change and urbanization., (2) thermal tolerance was higher in fish fed a high- vs. low-ration diet, indicating a causal link between nutrition and thermal tolerance and (3) found that thermally stressed fish showed a transcriptional response related to transcription regulation and responses to unfolded proteins, and alternatively spliced genes related to gene expression regulation and metabolism. Our results can inform conservation captive breeding efforts, translocation and reintroduction programs for redside dace and other imperilled species by helping to identify appropriate source populations.

AC1.36

LABRIFORM.

Thursday 6 July 2023 17:45

Jules B. L. Devaux (University of Auckland, New Zealand), Alice R. Harford (University of Auckland, New Zealand), Gillian

M. C. Renshaw (Griffith University, Australia), Tony J. R. Hickey (University of Auckland, New Zealand)

j.devaux@auckland.ac.nz

Hearts are the first organs to fail as marine ectotherms approach critical thermal limits. We found that just below heart failure, heart mitochondria in vitro increase oxygen demands, yet are not coupled to oxidative phosphorylation and fail to supply sufficient ATP. While mitochondrial uncoupling predicted heart failure, mitochondrial response has been previously assessed in vitro within isolated fibres, and in the presence of saturating substrates and oxygen. Here, we sought to assess mitochondrial response to heat stress in situ, within beating hearts exposed to ramping temperatures. Mitochondrial redox states were measured spectrophotometrically in thermo-controlled perfused hearts of a temperate (N. fucicola, 18ºC acclimated) and a tropical (S. ghobban, 26ºC acclimated) species of Labriform.

In N. fucicola, both synchronised beating rates and electroactivity of the heart increased gradually with temperature and inflected at 26±1ºC, mediating subsequent rapid heart failure. In S. ghobban, heart rates peaked at 28±1.5ºC and stabilised up to 36±3.4ºC, after which hearts became arrhythmic and failed to perform. In both species, mitochondrial flavin adenine dinucleotide and cytochromes spectra shifted coordinatively with heart rate divergences, observed in real-time. Cytochrome b absorbance analysis suggested loss of mitochondrial membrane potential, and further investigation of mitochondrial structures using electron-microscopy revealed cristae disruption at 25.4ºC and 36.7ºC in the temperate and tropical species, respectively. The findings highlight the importance of assessing mitochondrial response to heat stress in situ, to better understand marine ectotherm's cardiac performance and adaptation to changing temperatures.

MITOCHONDRIAL THERMOTOLERANCE IN HEARTS OF A TEMPERATE (NOTOLABRUS FUCICOLA) AND A TROPICAL (SCARUS GHOBBAN) SPECIES OF

ACPO1 - 100 YEARS OF SEBANIMAL

ORGANISED BY: JOHANNES OVERGAARD (AARHUS UNIVERSITY, WILLIAM JOYCE (AARHUS UNIVERSITY)

ACPO1.1A BIOCHEMICAL ADAPTATION IN THE 21ST CENTURY: HARNESSING THE POWER OF GENOMICS TO ADDRESS LONG-STANDING QUESTIONS OF ADAPTATION TO THE ENVIRONMENT

Tuesday 4 July 2023 09:00

Patricia M. Schulte (University of British Columbia, Canada) pschulte@zoology.ubc.ca

This centenary year for the Journal of Experimental Biology is also the 50th anniversary of the publication of “Strategies of Biochemical Adaptation”, which is the first of several books by Peter Hochachka and George Somero that were instrumental in founding the field of comparative biochemistry. In developing this new field, they took the philosophy and approaches of comparative physiology and applied them to questions at the biochemical level, resulting in a deeply integrative discipline that attempts to understand organismal function from the molecular level upwards. In this talk, I will look back at the fundamental insights developed by Hochachka and Somero and the key questions that they posed, and highlight how recent advances in genomics and genome editing mean that we are now poised to address these questions in exciting new ways.

ACPO1.2A THERMAL PERFORMANCE AND TOLERANCE OF ECTOTHERMS

Tuesday 4 July 2023 09:30

Rachael Morgan (University of Bergen, Norway) rachael.morgan@uib.no

A hot topic in eco-physiology is how ectotherms respond to global warming. However, this is not a new topic. Fry and colleagues have been working on how ectotherms respond to critical temperatures since the 1940s and a lot of the principles still in use today were established decades ago. So, how far have we progressed in this field? In this talk I will start by presenting some of the fundamental work that has shaped the field of thermal physiology. I will then show how the field has progressed, focusing on some of my own work investigating evolution of thermal tolerance limits and plasticity of thermal performance in ectotherms.

ACPO1.3A FROM THE CAMEL’S NOSE TO THE ORYX’S BRAIN: 100 YEARS OF INVESTIGATING HOW MAMMALS COPE WITH HEAT

Tuesday 4 July 2023 10:00

Andrea Fuller (University of the Witwatersrand, South Africa), Duncan Mitchell (University of the Witwatersrand, South Africa)

andrea.fuller@wits.ac.za

If trail-blazing comparative physiologists like Knut Schmidt-Nielsen, Dick Taylor, Virginia Finch and George Bartholomew were alive today, we suspect that they would be focusing their research efforts on understanding how organisms are responding to global heating. We provide examples to show how much of the seminal work that they and others did laid the foundation for our understanding of how mammals will respond to climate change. Regrettably, however, the ideas and concepts arising from their legacy, particularly those relating to the biophysics of heat exchange, have been ignored by many climate change modellers, sometimes rendering their models seriously inaccurate. We also show how modern experimental techniques, not available to those pioneering researchers, have advanced our understanding of how free-living terrestrial mammals respond to heat, and how both the foundational and the advanced knowledge are critical for the future conservation of mammals.

ACPO1.13 HISTORY OF STUDY AND EVOLUTION OF VERTEBRATE BLOOD GAS TRANSPORT – PEOPLE, ANIMALS, ENVIRONMENTS AND MECHANISMS

Tuesday 4 July 2023 13:30

Michael Berenbrink (University of Liverpool, United Kingdom)

michaelb@liverpool.ac.uk

The 20th century has seen a dramatic increase in our knowledge about vertebrate blood gas transport. While early researchers used animal or their own blood as resource for understanding human physiology (Bohr, Haldane), species differences in blood respiratory function soon became a central topic in comparative physiology. August Krogh postulated that each problem in physiology was best studied in specific animals, often adapted to environments where that

problem was most pressing. This spurred on the field of environmental physiology, where respiratory adaptations of animals, at high-altitude or in the deep ocean, were studied in their own right (e.g. the Root effect of fish blood). Revealing the atomic structures of sperm whale myoglobin and horse haemoglobin by Kendrew and Perutz spawned the rich field of comparative studies on haemoglobin structure-function relationships in vertebrates from Amazonia to Antarctica and deep-sea hydrothermal vents to the Himalayas. The growing understanding of the molecular and evolutionary underpinnings of the observed functional diversity is encapsulated by Perutz’s ‘Species adaptation in a protein molecule’ in the inaugural issue ofMolecular Biology and Evolution. Technical advances in sequencing and protein structure prediction have enormously tilted the ratio of haemoglobins with known structure to those with known function, but it is still difficult to predict functions like the Root effect from structure alone. However, progress in ancestral sequence reconstruction, ancient DNA sequencing, and recombinant expression now allows studying secrets of haemoglobin function from in the earliest vertebrates, to ice-age megafauna, and victims of human-caused extinctions like the great auk.

ACPO1.5 SENSORY BEHAVIOR AND ECOPHYSIOLOGY OF WILD BATS

Tuesday 4 July 2023 14:00

Laura Stidsholt (Aarhus University, Denmark), Mark Johnson (Aarhus University, Denmark), Stefan Greif (Tel Aviv University, Israel), Cynthia Moss (Johns Hopkins University, United States), Yossi Yovel (Tel Aviv University, Israel),

Peter Teglberg Madsen (Leibniz Institute for Zoo and Wildlife Research, Germany)

laura.stidsholt@bio.au.dk

All animals rely on sensing to survive. Approximately one in five mammals use echolocation as their primary sensory modality to navigate and locate food in total darkness. As small, nocturnal fliers, echolocating bats have a high metabolic rate that must be sustained by targeting small and often highly agile prey. Since Spallanzani's pioneering experiments in the 18th century, scientists have been intrigued by how bats hunt using only their voice and ears. Throughout the 20th century, bat echolocation and sound perception were explored intensively, particularly through captive behavioural and neurophysiological experiments that laid the foundation for exploring animal cognition and sensory perception, thanks to the work of Donald Griffin. Recent technological advancements, including radio tracking, GPS, and sensor loggers, have facilitated direct measurements of the movement, physiology, foraging, and fine-scale sensory-motor behaviour of wild bats. These developments have allowed us to understand how bats use echolocation to capture enough food to maintain their high energy requirements in the wild, and how their sensory and foraging behaviour is adapted to a changing world. With this talk, I will trace the evolution of bat echolocation research from Spallanzani to the present day, and explore how bats, which evolved their biosonar in a silent and dark world, are facing challenges from human encroachment in natural ecosystems, which are affecting their ability to maintain a positive energy balance in a modern world.

ACPO1.6 HOW DOES THE STORY END? A TALE OF INFECTIOUS DISEASE, HOST RESISTANCE, AND THE FATE OF FROGS

Tuesday 4 July 2023 14:30

Jamie Voyles (University of Nevada, United States)

jamie.voyles@gmail.com

How do epidemics end? A transition away from the outbreak phase of a disease can occur following the emergence of highly pathogenic infectious agents. Yet the mechanisms that underpin such transitions remain obscure. We have been investigating shifts in disease dynamics in the lethal disease amphibian chytridiomycosis by focusing on host recoveries in the amphibian assemblages of Central America. The fungal pathogen that causes chytridiomycosis,Batrachochytrium dendrobatidis(Bd), spread through Costa Rica and Panama in a wavelike pattern approximately two decades ago, causing mass mortality events and severe declines in many amphibian species. However, some host populations that survived initial outbreaks are persisting and even rebounding despiteBdinfection. We have found that infection patterns are heterogenous across populations, species, and geographical space. In some species,Bdprevalence and intensity of infection is now low, yet the pathogenicity ofBdisolates is still high, causing 100% mortality in naive hosts in controlled laboratory experiments. This finding suggests that shifts in host resistance and/or tolerance toBdinfection may be important mechanisms underpinning amphibian recoveries and ecological resilience. We also expect that focusing research efforts on other host traits, including innate and adaptive immune responses, the cutaneous microbiome, life history characteristics, and behaviour may offer promising avenues for further investigation to understand the mechanisms underpinning shifts in disease dynamics across spatial-temporal gradients.

ACPO1.7 THE ENDOCRINE REGULATION OF ORGAN GROWTH AND REMODELLING OF DIGESTING PYTHONS

Tuesday 4 July 2023 15:30

Tobias Wang (Aarhus University, Denmark), Katja Last (Aarhus University, Denmark), Emil Rindom (Aarhus University, Denmark)

tobias.wang@bio.au.dk

The humoral regulation of growth and tissue remodelling was a central theme during the early days ofJ Exp Biol. Much of the enthusiasm on this exciting topic was undoubtedly spurred by the crucial experimental demonstration of hormones by Starling and Bayliss 1904, founding the concept of endocrine regulation to the chagrin of Pavlov’s exclusive focus on neural regulation. We now know that virtually all organs function as secondary endocrine glands, releasing a plethora of hormones and signalling molecules with direct effects on other organs. This regulation underlies many of the orchestrated physiological and behavioural responses during digestion, and provides part of the signalling that enable phenotypic changes of the visceral organs when animals transition from famine to feast based on recent experiments on Burmese pythons, we demonstrate that humoral signalling from the small intestine drives the pancreatic release of insulin that stimulates postprandial protein synthesis and growth of various tissues, including skeletal muscle.

ACPO1.8 PRENATAL THYROID HORMONES IN BIRDS

Tuesday 4 July 2023 16:00

Suvi Ruuskanen (University of Jyväskylä, Finland), Bin-Yan Hsu (University of Turku, Finland), Tom Sarraude (University of Groningen, Netherlands), Antoine Stier (CNRS Strasbourg, France)

suvi.k.ruuskanen@jyu.fi

The critical role of thyroid hormones on development was described already in the early 1900s. Thyroid hormones are key coordinators of thermoregulation, reproduction, migration, and changes due to endocrine disrupters have also been discovered. Yet today, thyroid hormones are still understudied compared to other hormones, especially in research on wild populations and species. Furthermore, the role of maternal thyroid hormones has been largely ignored, and data from birds is generally rather limited. We have shown large variation among species, populations, individuals and even within clutches in maternal thyroid hormones deposited in eggs in birds. The variation is explained by life-history traits and environmental variation. In a series of experiments using five different study models, we have recently demonstrated how variation in maternal thyroid hormones influences offspring phenotype and physiology pre- and postnatally across species, with potential long-term consequences, yet the results are contradictory across the studied species. Future studies should address these inconsistencies and the adaptive value of variation in maternal thyroid hormone levels.

ACPO1.9 A BRAIN THAT SURVIVES WITHOUT OXYGEN, A COMMON CONNECTION TO

DUKE UNIVERSITY

Tuesday 4 July 2023 16:30

Leslie Buck (University of Toronto, Canada), Alex Myrka (University of Toronto, Canada), Haushe Suganthan (University of Toronto, Canada), Domenic Di Stefano (University of Toronto, Canada) les.buck@utoronto.ca

The mammalian brain only survives a few minutes without oxygen, but the turtle brain of freshwater painted and red-eared slide turtles survives many hours to months without oxygen. The foundation of our current knowledge of the underlying mechanisms of this ability lies at the confluence of four remarkable scientific careers in the 1960’s. At Duke University the famed comparative physiologist Knut Schmidt-Nielsen established his research laboratory and attracted the attention of Peter Hochacka, Donald Jackson and Peter Lutz. Jackson made the first calorimetric measurements of a reversible metabolic arrest in the Schmidt-Nielsen Lab in 1966, subsequently Lutz demonstrated the maintenance of ion gradients in anoxic turtle brain and Hochachka explored mechanisms of metabolic arrest and formulated the metabolic and ion channel arrest concepts. “On the shoulders” of these individuals I have advanced my own research on anoxia-tolerant turtle brain and have uncovered evidence of ion channel arrest and in a special case of enhanced ion channel activity. I will give an overview of this evidence and show recent data showing ion channel arrest in turtle liver cells.

ACPO1.10 KROGH’S INSECT SUBMARINES: THE NOVEL ROLE OF RESILIN IN THE BUOYANCY CONTROL OF PHANTOM MIDGE LARVAE

Wednesday 5 July 2023

09:00

Philip G.D. Matthews (University of British Columbia, Canada), T. Ames (University of British Columbia, Canada), Ben J Matthews (University of British Columbia, Canada), Evan K. McKenzie (University of British Columbia, Canada)

pmatthews@zoology.ubc.ca

Besides teleost fish, only one other group of aquatic animals has evolved the ability to control their buoyancy using compressible gas-filled bladders: the larvae of the phantom midge (Chaoborus). By the early 1900s, studies had revealed that fish release oxygen from haemoglobin in their blood to inflate their swim bladder, and shrink it by absorbing oxygen back into their blood. While the similarity between the function of the swim bladder of a fish and the four tiny air-sacs of aChaoboruslarva had long been noted, the absence of haemoglobin in these near-transparent insects suggested the presence of a very different buoyancy control mechanism. August Krogh tackled this problem in 1911, ruling out oxygen secretion but failing to identify the actual mechanism. Developments in knowledge and techniques across a range of disparate fields in the intervening 100 years have made it possible to finally characterise the unique buoyancy control system ofChaoborus.

ACPO1.11 INSECT OSMOREGULATIONA KEY TO EXTRAORDINARY SUCCESS

Wednesday 5 July 2023

09:30

Julian A.T. Dow (University of Glasgow, United Kingdom) julian.dow@glasgow.ac.uk

In terms of species, insects are the most diverse Class of life. They are able to exploit a remarkable range of ecological niches, and their survival depends on their ability to regulate their internal enviroments in the face of extreme challenges, which are addressed with modifications on the same basic body plan. This talk will review some of the diversity of osmoregulatory strategies in Class Insecta, with particular reference to the structure and function of the Malpighian (renal) tubules and the alimentary canal.

ACPO1.4 THE PHYSIOLOGY OF BREATH-HOLD DIVING; THE SCHOLANDER LEGACY AND START OF PHYSIO-LOGGING.

Wednesday5 July 2023

11:00

Andreas Fahlman (Oceanogràfic, Spain)

afahlman@oceanografic.org

In 1940, Per Scholander published his seminal paper “Experimental investigations on the respiratory function in diving mammals and birds” that summarized much of the understanding about the physiological responses and adaptations of species that breath-hold dive. While some of the physiological responses had been described earlier, Scholanders treatise provided a unifying summary of the cardiorespiratory responses while diving. This included the dive response, with a reduced cardiac output conserving blood oxygen to the central organs. Scholander also proposed that the anatomy of the respiratory system would aid in alveolar collapse and cessation of gas exchange at depth. Development of miniature-electronics that could measure and record physiological function (i.e., Physio-logging) allowed pioneering field studies by several researchers, e.g Gerry Kooyman. These studies showed that although the dive response was present in free-ranging animals, it was highly variable and seldom as pronounced as during forced dives, suggesting that dive adapted animals have a conditioned capacity to vary heart rate. Physio-logging also provided evidence of alveolar collapse in seals and dolphins, where alveolar compression occurs at shallow depths while complete atelectasis much deeper. The combination of these past studies provided evidence for the “selective gas exchange hypothesis” which provides an explanation how breath-hold diving species manage gases while diving, and how man-made disturbance and climate change may alter this ability. This presentation will provide a summary of the work that followed Scholanders publication and present our current knowledge 83 years later.

ACPO1.12 FISH GUT CALCIFICATION: MULTI-FACETED PHYSIOLOGY AND ROLE IN OCEAN CHEMISTRY

Wednesday 5 July 2023 10:00

Rod W. Wilson (University of Exeter, United Kingdom)

r.w.wilson@exeter.ac.uk

Marine bony fish precipitate calcium (from drinking seawater and dietary sources) as carbonate minerals within their alkaline and bicarbonate-rich intestinal fluid and continuously excrete these at remarkably high rates. This precipitation can double intestinal water absorption and limit calcium absorption and kidney stones – both essential in the dehydrating and hypercalcaemic marine environment. Physiological implications of net intestinal bicarbonate (base) excretion include: 1) matching net H+ absorption and localised acidosis in the intestinal vasculature causing 2) a Bohr/Root-enhancement of intestinal O2 delivery by upto 42%; 3) anatomically-separate excretion of this excess acid (via gills) for acid-base regulation; 4) a disconnect for the normally ~1:1 gill exchange of O2 and CO2 with ~10 % of respiratory CO2 excreted via the gut as HCO3 - or CaCO3 . This reaches ~50% in the champion of high salinity tolerance (Arabian killifish, Aphanius dispar). The physiological ramifications of this intestinal process are thus wide-ranging, but it also plays an important role in the marine inorganic carbon cycle. In 2009 models estimated that fish contribute 3-45% of total global CaCO3 production. However, experiments on the effects of temperature, salinity, body size, feeding, hypoxia and high CO2 all suggest that fish produce far more than previous estimates, and that climate change will accelerate this further. A key question is whether the most abundant but least understood marine fishes, the diel-vertically-migrating mesopelagics, operate a novel oceanic ‘upward alkalinity pump’ by gut precipitation at depth and near-surface excretion of high solubility carbonates (high Mg calcite), replenishing surface ocean alkalinity.

ACPO1.14 ADRENERGIC REGULATION OF THE HEART: FROM GASKELL’S CROCODILES TO COMPARATIVE PHARMACOLOGY AND MOLECULAR PHYLOGENETICS

Wednesday 5 July 2023 11:30

William Joyce (Aarhus University, Denmark) william.joyce@bio.au.dk

Since the pioneering experiments of Walter Holbrook Gaskell, which involved using exotic creatures including crocodiles and tortoises to uncover the fundamentals of the sympathetic nervous system, the history of comparative physiology and adrenergic regulation of the cardiovascular system have been closely entwined. The discovery of numerous adrenergic receptor sub-types in the mid-to-late twentieth century was accompanied by the burgeoning field of comparative pharmacology, during which pharmacological-heavyweights such as Geoffrey Burnstock were instrumental. In recent times, the dawn of comparative genomics and transcriptomics have allowed a more detailed appreciation of the diversity of adrenergic receptor subtypes that can be found across different groups of vertebrates, whilst molecular genetic techniques (including gene knockouts) are able to precisely uncover the roles of specific adrenergic receptors.

ACPO1.15 FROM HODGKIN-HUXLEY TO THRESHOLDS TO BIOLOGICAL RELATIVITY: EXCITABILITY STILL EXCITES!

Wednesday 5 July 2023 12:00

Holly A. Shiels (University of Manchester, United Kingdom) holly.shiels@manchester.ac.uk

The work of Alan Hodgkin and Andrew Huxley at the Physiological Laboratory in Cambridge and the Marine Biological Association in Plymouth revolutionised our understanding of cell excitability and garnered them the 1963 Nobel Prize. Their legacy is our comprehension of how voltage-gated ion channels give rise to action potentials both experimentally and mathematically. Experimentally they developed the voltage-clamp technique and established the field of electrophysiology. By utilising giant axons from squid their work forms a classic example of the August Krogh principal. Mathematically, the equations they derived from their experimental work represents the first quantitative description of electrical excitability in cells and set the foundation for the coupling of experimental and computational science. The HodgkinHuxley model still forms the basis of computational modelling of excitable cells today. This talk will reflect on these historic contributions and then demonstrate their relevance for some of the most important questions in physiology and biology today: from what goes wrong with propagation of excitation at environmental extremes to the integration of life across levels of biological organisation.

ACPO1.16 MUSCLE CONTRACTION AND THE SLIDING (STRETCHING AND DILATING) FILAMENT HYPOTHESIS

Wednesday 5 July 2023 15:00

Tom Daniel (University of Washington, United States), S A Malingen (University of Washington, United States), A Von Hagel (University of Washington, United States), E Lauga (University of Washington, United States)

danielt@u.washington.edu

Two groundbreaking papers published in 1954, led by Andrew Huxley, laid out the theory of the mechanism of muscle contraction based on molecular interactions between myofilaments in the sarcomere that cause filaments to slide past one another during muscle contraction. These and subsequent papers established the classic “sliding filament hypothesis”. In the subsequent decades of research, new computational and experimental approaches have allowed us to understand this complex multi-scale process, from force generation to energy delivery at the molecular, cellular and tissue levels of organization. The vast swath of research in this domain underlies our understanding of animal movement, human disease, and biomimetic technologies. And, as it turns out, new data suggest that the filaments not only slide, they stretch and dilate as well. These additional axial and radial motions have profound implications to how energy may be stored and how substrates may be delivered via diffusion and fluid motions. Both historical and current approaches of this fundamental biomechanical process will be explored, with a focus on the complex dynamics of the myofilament lattice and new ideas emerging about multi-scale physics.

ACPO1.17 MUSCULOSKELETAL BIOMECHANICS: FROM

PIONEERS

TO

CUTTING-EDGE RESEARCH TO UNCOVER ANIMAL MOVEMENT

Wednesday 5 July 2023 15:30

Pauline Provini (National Museum of Natural History, France)

pauline.provini@cri-paris.org

How do animals move and interact with their environment? How do they achieve critical functions like locomotion, feeding, or communication? Biomechanics seeks to answer these questions by combining experimental observations with mechanical and mathematical modelling, allowing researchers to gain insights into the mechanics of animal movement. Over the years, musculoskeletal biomechanics, studying how muscles, bones, joints, and tendons work together to produce motion, has made significant conceptual leaps, often linked to technical and modelling advances. In this talk, I will highlight some of the significant historical milestones in biomechanics, and showcase pioneering figures who paved the way for the latest cutting-edge research. By understanding their ideas and methods, we can appreciate how they have helped to shape our understanding of animal movement and more generally of the evolution and diversity of animal form and function, a central theme at SEB for the past decades.

ACPO1.18 INTEGRATING ANIMAL FLIGHT AERODYNAMICS TO THE UNDERLYING DYNAMICS OF MUSCLE POWER OUTPUT

Wednesday 5 July 2023 16:00

Andrew A. Biewener (Harvard University, United States) abiewener@oeb.harvard.edu

Over the past five decades, the SEB has provided an exciting and critically important forum for sharing ground-breaking research on the aerodynamics of invertebrate and vertebrate animal flight, animal flight performance in relation to migration, and the morphology, physiology and dynamics of muscle contractile function that provides the mechanical power output for flight. Highlights of novel research discoveries underlying animal flight performance will be briefly reviewed and linked to the neuromuscular function of flight muscles that power vertebrate flapping flight. High-speed video, robotic models, particle imaging of fluid flow, computational fluid dynamics modelling, and in vivo methods for recording muscle function have all been key approaches to gaining critical insight into the aerodynamic mechanisms and the muscle power output requirements for flight. Newly emerging techniques and technologies provide the opportunity to explore animal flight performance in the field, offering a rich set of future discoveries linked to the ecology of our changing world.

ACPO1 - 100 YEARS OF SEBCELL

BY: DAVID EVANS (BOOKES UNIVERSITY)

ACPO1.1C A HISTORY AND OVERVIEW OF PLANT CELL CYCLE RESEARCH

Tuesday 4 July 2023 09:00

Jim Murray (Cardiff University, United Kingdom)

MurrayJA1@cardiff.ac.uk

This year is not only the 100th anniversary of the SEB, but also the 70th anniversary of the seminal description of the phases of the cell cycle by the radiologist Alma Howard and Stephen Pelc in 1953 at the MRC Radiotherapeutic Research Unit at Hammersmith Hospital, London. This foundational work was carried out by monitoring the incorporation of 32P in the nuclei of cells in the roots of the broad beanVicia fabaand showed that DNA synthesis occurred at a discrete time, defining a “cell cycle”. Subsequent work in analyzing the cell cycle largely switched to more genetically or biochemically tractable systems for the following 35 years until interest switched back to understanding the conserved and divergent aspects of control of the cell cycle in plant cells. The SEB through its meetings has been a longstanding supporter and advocate for studies in the plant cell cycle, and has thus been an important contributor to building this field. The talk will summarise landmark developments and seek to present some of the current challenges in the field.

(Howard, A. and Pelc, S.R. (1953) Heredity, 6 [Supplement] 261-273; See alsohttps://www.nature.com/articles/426759a“Celebrating 50 years of the cell cycle”.)

ACPO1.2C SEB AND ENDOMEMBRANE AND CYTOSKELETON RESEARCH

Tuesday 4 July 2023 09:30

Verena Kriechbaumer (Oxford Brookes University, United Kingdom), Michael J Deeks (University of Exeter, United Kingdom)

vkriechbaumer@brookes.ac.uk

The endoplasmic reticulum (ER) and actin cytoskeleton are both essential for cellular functioning, and act in concert across a diverse suite of cellular processes. The ER is primarily responsible for the synthesis, packaging and quality control of critical cellular components such as proteins and lipids. The actin cytoskeleton, through the action of actin-binding proteins, which physically link actin filaments to a variety of cellular constituents, is required for cellular processes such as cell division, endocytosis and immunity. The actin cytoskeleton is also the driver of gross ER remodelling and the movement and positioning of other membrane-bound

organelles such as Golgi bodies. Rapid ER membrane remodelling is a feature of most plant cells and is important for normal cellular processes, including targeted secretion, immunity and signalling.

In the SEB Centenary Conference, we will discuss the exciting past and present research on intEResting and intER-ACTINg structures as well as the next but surely not final frontiers.

ORGANISED

ACPO1 - 100 YEARS OF SEBPLANT

ORGANISED BY: PROF STEPHEN LONG (UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, UNITED STATES

ACPO1.1P PHOTOSYNTHESIS IN THE SEB YESTERDAY, TODAY AND TOMORROW - FROM MOLECULAR TO GLOBAL SUSTAINABILITY SOLUTIONS

Friday 7 July 2023 09:00

Prof Stephen Long (University of Illinois at UrbanaChampaign, United States

slong@illinois.edu

Photosynthesis is the most important process on the planet. Indeed, it has made much of what the planet is today. Directly or indirectly it provides all of our food, and fuels almost all ecosystems. The SEB has been party to much of the discovery of how it works and advances in its measurement and analysis from molecules to landscapes. Presidents, Medalists, Woolhouse Lecturers and PEPG have been and are major contributors, as I will illustrate. Discovery and technical progress has expanded in two directions.

1) Growth in food demand is outstripping growth in production, reversing this situation is critical to avoiding increasing starvation and expansion of agriculture into tropical forests. For our major crops improving photosynthesis appears the remaining option for increasing genetic yield potential. Elucidation of the underlying gene expression networks and metabolic flux analysis are guiding engineering, including editing, of amounts and forms of key proteins to improve photosynthetic efficiency under global change. This has already led to on farm demonstrations of increased yield and promises many more.

2) The need to understand sinks for CO2 has motivated improved measurement and analysis of photosynthesis at scale. This is critical to identifying sinks and the engineering of managed systems for improved sequestration. Afforestation and planting of other sustainable productive perennials are providing means to offset emissions. These though could be greatly enhanced by engineering and breeding increased photosynthetic efficiency, especially if combined with combustion carbon capture and storage. Going forward photosynthesis may never have been more important.

AP1 - LOOKING BACKWARDS AND FORWARDS AFTER A DECADE OF CONSERVATION PHYSIOLOGY

ORGANISED BY: STEVEN COOKE (THE JOURNAL OF CONSERVATION PHYSIOLOGY), CHRISTINE MADLIGER (UNIVERSITY OF WINDSOR), CRAIG FRANKLIN (UNIVERSITY OF QUEENSLAND), KEVIN HULTINE (DESERT BIOLOGICAL GARDEN), JODIE RUMMER (JAMES COOK UNIVERSITY), KEVIN HULTINE (DESERT BIOLOGICAL GARDEN), JODIE RUMMER (JAMES COOK UNIVERSITY)

AP1.7 AN EARLY CAREER RESEARCHER’S REFLECTION ON THE PAST, PRESENT, AND FUTURE OF CONSERVATION PHYSIOLOGY

Thursday 6 July 2023 09:00

christine.madliger@algomau.ca

By applying physiological knowledge and concepts to conservation challenges, Conservation Physiology is inherently a mission-oriented discipline. Over time, the field has expanded to include a large complement of physiological metrics that are leveraged to help solve conservation problems across taxa, ecosystem types, and geographic locations. As someone whose research has fallen under the umbrella of Conservation Physiology throughout their graduate work, postdoctoral positions, and early career as an academic, I will outline my perspective on the growth and future of the discipline. I will place emphasis on the importance of collaboration, community, inclusivity, emerging techniques, and validations. My discussion will also cover some of the misconceptions associated with Conservation Physiology in relation to its scope and application, where effort can therefore be placed to increase participation in the field. Given the pace of environmental change and biodiversity loss, it is increasingly important to have a variety of conservation-focused disciplines that can provide solutions, and I will highlight how Conservation Physiology can fit into the larger multi-disciplinary conservation toolbox.

AP1.8 ENCOUNTERS WITH THE CONSERVATION PHYSIOLOGY

OF DESERT BIOTA

Thursday 6 July 2023 09:30

We should not let our concern about desertification under climate change deter us from a commitment to conserving ancient deserts. The biota of fog-dependent deserts (e.g. Namib, Baja California, Omani) are under particular threat because, with global warming, fog is disappearing almost everywhere. My encounters with desert physiology started with exploring whether Namib Desert lizards developed fevers, but soon transformed into trying to discover analyse whether thermal factors or water vapour pressure drove sand-swimming Namib animals to stay underground, where they spend most of their lives. We know of 48 species of Namib animal that depend on intermittent and unpredictable fog as their main source of water. How did their physiology evolve to manage unpredictable drinking? Some have evolved to extract water vapour directly from unsaturated air. Why do they not use fog droplets? Can the iconic Namib oryx survive without drinking? Arabian oryx do so, and we discovered how they do so, in the Saudi Arabian deserts, using biologging of free-living animals. Desert animals facing water scarcity need to avoid solar radiation. The best strategy for those that can is burrowing or sand-swimming; for those that can’t it is switching activity to the night.Conservation Physiologyhas carried little about desert physiology in its first decade. Hopefully that trend will be reversed, not just in the interests of desert conservation, but because the ways that desert biota have evolved to manage water will inform the conservation of biota elsewhere, facing global aridification.

AP1.9 CONSERVATION PHYSIOLOGY FOR THE FUTURE: A PLANT PERSPECTIVE

Thursday 6 July 2023 09:45

Kevin Hultine (Desert Botanical Garden, United States)

khultine@dbg.org

duncanmitch@gmail.com

Wild plants are not only the foundation of energy and nutrient fluxes throughout the globe, they have structured human civilization for millennia. However, the Anthropocene has brought increased risk of extinction for many plant species in virtually every biome on the planet. As editors ofConservation Physiology, we believe that mitigating extinction risk of threatened and endangered plants requires wellinformed management and policy decisions, that draws on core physiological principles. This presentation will first review how the conservation physiology toolbox has evolved over the last decade

Christine Madliger (Algoma University, Canada)

Duncan Mitchell (University of the Witwatersrand, South Africa)

to inform and inspire the conservation of at-risk plant taxa. I will then chart a path forward for addressing emerging conservation threats to wild plants, with a particular emphasis of threats caused by episodic heat waves and drought. I will review how current and future conservation in practice can be shaped by recent advances in the fields of genomics, phenomics, and remote sensing combined with core principles in physiology. As technological advancement of these tools continues to grow, the journalConservation Physiologyis poised to serve as a nexus between science application and conservation practice of at-risk plant taxa.

AP1.10 SOLUTIONS FOR FARMERS AND FOOD FOR BEES: FROM KNOWLEDGE ON BEE PHYSIOLOGY TO ACTIONS PROMOTING BEE CONSERVATION.

Thursday 6 July 2023 10:00

Mathilde L Tissier (Bishop's University, Canada)

mathilde.tissier@hotmail.com

Agricultural biodiversity is declining worldwide, threatening food security and human health. On average, 70% of fruit and vegetable pollination depends on wild bees. Bees also play a major role in pollinating wild plants, thus maintaining the integrity of terrestrial ecosystems. However, populations of native bees are declining, and several species are threatened with extinction. Main threats are habitat loss, parasitic infections, malnutrition, pesticide exposure and climate change that individually or interactively affect bee populations. Nonetheless, most of the focus has been on non-native and managed honeybees, whilst information and actions on wild bees are comparatively lacking. To preserve native bees whilst ensuring human food production, we worked on:

1. Re-establishing a two-way dialogue with farmers and integrate their considerations when initiating conservation research and projects;

2. Improving our knowledge of the nutrition and health of native and/or wild bees; Working with more than 30 partners, including farmers, beekeepers, ENGOs, companies, government advisers, and academics, we are conducting research to improve the resistance and resilience of native bees towards environmental stress, while implementing solutions are relevant to farmers in a commercial production context.

the mode of action of pollutants and the adverse outcomes at the organismal and population level. These molecular and physiological endpoints can be used as biomarkers, applicable in the field. This brings ecotoxicological research much closer to conservation physiology. Understanding the relationships between chemical reactivity in the environment and in organisms, e.g. reduced survival and reproduction, and assessing the consequences at higher levels, e.g. reductions in population size and biodiversity, allows conservation physiologists and managers to take the right restoration measures for an optimal improvement of the habitats of concern. For example, the promising approach of mechanistic-based Adverse Outcome Pathways (AOPs) could play an important in ecotoxicological research and conservation management. It studies a pathway of events, from the direct interaction of a chemical with a molecular target, through subsequent intermediate events at cellular, tissue, organ and individual organism levels which then result in an Adverse Outcome (AO) relevant to ecotoxicological risk assessment and regulatory decision-making. In this context, we also discuss the importance of modeling, including bioavailability based and effect based models and meta-analysis studies to detect unifying physiological processes, as well as interesting outliers.

AP1.12 CULTURE, TRANSPORT, AND POPULATION SUPPLEMENTATION METHODS TO SUPPORT CONSERVATION OF AN ENDANGERED ESTUARINE FISH

Thursday 6 July 2023 11:00

Nann A Fangue (University of California Davis, United States), Nicholas Hudson (University of California Davis, United States), Garfield Kwan (University of California Davis, United States), Dennis E Cocherell (University of California Davis, United States), Brittany Davis (Department of Water Resources, United States), Brian Schreier (Department of Water Resources, United States), Trishelle Temple (Department of Water Resources, United States), Daphne A Gille (Department of Water Resources, United States), Scott Meyer (Department of Water Resources, United States), Melinda R Baerwald (Department of Water Resources, United States)

nafangue@ucdavis.edu

Thursday 6 July 2023 10:15

Gudrun De Boeck (University of Antwerp, Belgium), Essie M Rodgers (Murdoch University, Australia), Raewyn M Town (University of Antwerp, Belgium)

gudrun.deboeck@uantwerpen.be

Over the past decades, due to the endless combinations of mixture toxicities, ecotoxicological research moved toward a mechanistic understanding of toxicological processes. It uses trait-based approaches and sublethal molecular and physiological endpoints to understand

The Delta Smelt (Hypomesus transpacificus) is a federally threatened and California endangered species endemic to the upper San Francisco Estuary (SFE). Since 1996, a captive population has been maintained, and more recently experimental releases have been initiated to supplement wild populations. Because Delta smelt are sensitive to handling and transport stress, it is unclear how individuals will survive outside of hatchery conditions upon release. We designed in situ enclosures to facilitate smelt soft release following acclimation to field conditions. We performed hydraulic modeling and evaluated cage screen material permeability to prey items by measuring energy dissipation and flow deflection in a large flume. The final cylindrical enclosure is stainless steel wire mesh with 60% openness (1.0m diameter, 1.3m tall). We then investigated survival, growth, and feeding of cultured smelt in three, one-month deployments in an experimental pond before testing these cages in an open water setting. Gut contents showed that cultured smelt quickly transitioned to natural food, and survival was 94-100%. We are also studying transport methodologies to minimize stress. Current transport to release practices represent two consecutive multi-stressor events that affect salinity (0.2 to 5 to 0.1 ppt), oxygen (18.7 to 10 to 12 mg/L), and pH (8.0 to 7.0 to 8.2). These ionic, osmotic and acid-base challenges are reflected in changes in

AP1.11 USING ECOTOXICOLOGY FOR CONSERVATION: FROM BIOMARKERS TO MODELING.

apical morphology of smelt gill ionocytes (via widened apical pits and extended microvilli), and in the generalized stress response. We continue to focus on solutions that promote natural smelt foraging, behavior, and survival upon release.

AP1.14 REFLECTIONS ON A DECADE OF CONSERVATION PHYSIOLOGY

Thursday 6 July 2023 11:30

Steven J Cooke (Carleton University, Canada)

steven_cooke@carleton.ca

A decade ago we were celebrating the launch of the journal Conservation Physiology. Co-owned by the Society for Experimental Biology (SEB) and Oxford University Press, it became the first solely open access journal in the SEB portfolio. The journal now has steady (and growing) copy flow and has become a well-respected outlet for solutionsoriented and mechanistic conservation science. We gather on the 10th anniversary of the journal to reflect on the past and consider the future. This presentation will be delivered by the founding Editor-inChief and will serve as a springboard for a lively panel that will follow.

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

AP1.1 TEMPERATURE EFFECTS THE ENDURANCE SWIMMING PERFORMANCE OF JUVENILE GREEN STURGEON (ACIPENSER MEDIROSTRIS)

Wednesday 5 July 2023 POSTER SESSION

Nann A Fangue (University of California Davis, United States), Anna E Steel (University of California Davis, United States), Sarah E Baird (University of California Davis, United States), Dennis E Cocherell (University of California Davis, United States), Kelly D Hannan (University of California Davis, United States)

nafangue@ucdavis.edu

Sturgeon are threatened by anthropogenic changes to river systems, but there are no established protocols for determining their risks from water diversions. Previous studies suggest that laboratory evaluations of swimming performance are an effective way to describe susceptibility to entrainment or other harm. We quantified swimming performance of threatened green sturgeon, Acipenser medirostris, acclimated to 13°Cor 18°C using fixed velocity endurance tests. Cold-acclimated juvenile green sturgeon (13°C) had reduced endurance swimming ability and were more likely to employ energy saving behaviours (i.e., station holding) compared to warm-acclimated fish (18°C). Regardless of acclimation temperature, immediately after the swim trials, juvenile green sturgeon had increased cortisol when utilizing prolonged swimming strategies (time to fatigue: 5-200min) compared

to control non-swimming fish, rapid swimming fish (time to fatigue < 5min), and sustained swimming fish (time to fatigue >200min) suggesting that juvenile green sturgeon are experiencing stress when swimming to exhaustion. Warm-acclimated fish (18°C) had elevated whole-body lactate when utilizing prolonged and rapid swimming strategies compared to the other swimming types. However, no changes were observed in the lactate concentrations of fish acclimated to 13°C. The fixed velocity endurance tests, station holding, and lactate responses suggest that warm-acclimated green sturgeon were utilizing anerobic metabolism and able to sustain endurance swimming longer than cold-acclimated fish, which were focusing more energy saving behaviours. Management should take water temperatures into account when making recommendations about intake flows (approach velocities) of water diversions as cold-acclimated fish were more likely to become entrained than their warm-acclimated counterparts.

AP1.2 CONDUCTING FIELD-BASED PHYSIOLOGY TO INFORM CONSERVATION MANAGEMENT OF A THREATENED SALMONID SPECIES ACROSS DIFFERENT HABITATS

Wednesday 5 July 2023 POSTER SESSION

Terra L Dressler (University of California Santa Barbara, United States), Kara Anlauf-Dunn (Oregon Department of Fish and Wildlife, United States), Erika J Eliason (University of California Santa Barbara, United States) tdressler@ucsb.edu

Salmonid fishes are a focal point of conservation physiology due to their high value to humans and their susceptibility to decline from climate change. A significant challenge in conserving these fishes is that populations of the same species can be locally adapted to vastly different habitats, and can therefore have unique tolerance or vulnerability to environmental stressors within those habitats. This is particularly true for Oncorhynchus mykiss, or steelhead trout, a species that inhabits the entire west coast of North America from California to Alaska. Although this species is typically reported to prefer cold water, O. mykiss populations are found in both cool, coastal waters and arid, inland environments throughout their range. The present study focuses on 4 populations of summer run O. mykiss inhabiting desert and coastal river systems within the state of Oregon, USA. Here, in partnership with scientists at the Oregon Department of Fish and Wildlife, we paired streamside physiological experiments with stream temperature monitoring to assess each population’s functional and critical thermal tolerance as well as vulnerability to warming. Each population was tested within its natal waters and was exposed to ecologically relevant fluctuating temperatures. All populations had unique responses to temperature change but, overall, O. mykiss from warmer habitats appear to be more vulnerable to warming despite having higher thermal tolerance than O. mykiss from cooler habitats. These results are currently being used to prioritize conservation management efforts for summer steelhead in Oregon.

AP1.3 BABY SHARKS IN DISTRESS: A PHYSIOLOGICAL QUEST FOR CHRONIC STRESS BIOMARKERS IN NEONATAL BLACKTIP REEF SHARKS

(CARCHARHINUS MELANOPTERUS)

Wednesday 5 July 2023 POSTER SESSION

Shamil F. Debaere (University of Antwerp, Belgium), Shari Schlueter (James Cook University, Australia), Serge Planes (Centre de Recherches Insulaires et Observatoire de l'Environnement, French Polynesia), Gudrun De Boeck (University of Antwerp, Belgium), Jodie L. Rummer (James Cook University, Australia)

shamil.debaere@uantwerpen.be

Decades of overexploitation and habitat degradation have profoundly impacted sharks, leaving a third of all species threatened with extinction. To effectively guide and improve conservation efforts, a profound knowledge on the stress physiology of sharks is urgently needed. A key research gap that requires particular attention are the effects of anthropogenic and environmental stressors on these ancient fishes. However, finding biomarkers of chronic stress in sharks has proven to be a challenging task due to their unique stress hormone, 1α-hydroxycorticosterone (1α-OHB). Because the role of 1α-OHB in sharks remains equivocal, we aim to experimentally determine the utility of 1α-OHB as an indicator for chronic stress and unravel the metabolic action of 1α-OHB to identify novel biomarkers to be added to the physiology toolbox for shark conservation. Additionally, for the first time, we shed light on the tertiary effects of chronic stress in sharks and help determine to what degree the chronic phase of the stress response reflects changes that could compromise fitness. Preliminary results suggest that whilst specific growth rates and food conversion efficiency appear to decrease with chronic stress in neonatal blacktip reef sharks (Carcharhinus melanopterus), levels of circulating glucose are maintained relatively constant and are therefore not a good indicator for chronic stress. This study aims to unravel the biochemical and molecular underpinnings of the apparent wholeorganism responses to stress to determine thresholds and tipping points and the capacity for this and potentially other species, during this vulnerable life stage, to acclimatise and adapt over the long term..

AND EARLY LIFE SUCCESS

Wednesday 5 July 2023 POSTER SESSION

Garfield T Kwan (University of California Davis, United States), Hamilton W Fennie (NOAA Alaska Fisheries Science Center, United States), Noah J Ben-Aderet (Ocean Protection Council, United States), Rasmus Swalethorp (Scripps Institution of Oceanography University of California San Diego, United States), Kamran Walsh (Scripps Institution of Oceanography University of California San Diego, United States), Scott L Hamilton (Moss Landing Marine Laboratories, United States), Cheryl A Logan (California State University Monterey Bay, United States), Neosha S Kashef (NOAA Southwest Fisheries Science Center, United States), David M Stafford (NOAA Southwest Fisheries Science Center, United States), Nann A Fangue (University of California Davis, United States), Andrew R Thompson (NOAA Southwest Fisheries Science Center, United States)

gkwan09@gmail.com

Over the past decades, robust otolith biomineralization patterns in teleost fishes have allowed researchers to protect fisheries via agestructured modeling, reconstruct life history and dietary patterns, and more. The otolith is a CaCO3 microstructure that biomineralizes in a concentric ring pattern within the inner ear endolymph, and the otolith core (aka the nuclear radius) is its first complete ring. Importantly, wider otolith core width has recently been correlated with larger size-at-parturition, faster growth rate, improved foraging success, and greater survival during the larval stage across multiple species with very different adult life histories. Current hypotheses attribute variance in otolith core size to maternal investment, environment during gestation period, number of offspring, or any combination of the above. Although the otolith core appears to be a promising metric useful for fishery science and conservation biology, climate change research has shown warming, hypoxia, and acidification can impact biomineralization patterns. Therefore, it is imperative to understand mechanistically how these environmental factors affect otolith biomineralization so that otolith indicator potential can better be optimized and utilized now and in the future. This study seeks to determine whether maternal size, environmental CO2 and O2 condition, and number of offspring affect otolith core size, size-at-hatch, and other early life metrics in various rockfishes (Sebastes spp.). Our results will be critical to identifying the mechanism driving core size variance, optimizing current-day otolith-reliant tools, and validating another metric useful for fisheries, recruitment, and conservation assessments.

AP1.5 DEDUCING THE MECHANISM RESPONSIBLE FOR VARIANCE IN LARVAL OTOLITH CORES, A METRIC OF MATERNAL INVESTMENT

CP1 - GENERAL CELL AND PLANT BIOLOGY

POSTER SESSIONS

Wednesday 5 July 2023 17:15-19:15

CP1.1 ENGINEERING CROPS FOR IMPROVED FREEZING TOLERANCE AND BETTER YIELDS

Wednesday 5 July 2023 POSTER SESSION

Morgan Lee (Durham University, United Kingdom), Heather Knight (Durham University, United Kingdom)

sgng77@durham.ac.uk

Frost-induced crop losses significantly decrease yield. Therefore, identifying genes involved in freezing tolerance is of agricultural importance. Arabidopsis thalianaSFR5was identified in 1996 as one such gene, due to its mutant’s sensitivity to freezing temperatures. More recently, next generation sequencing has allowed a number ofSFR5candidate genes to be identified, includingAVP1. AVP1 is primarily known as a vacuolar proton pumping pyrophosphatase, utilising the energy derived from the hydrolysis of pyrophosphate to transport protons across the tonoplast. In doing so, it impacts the cytoplasmic PPi content. However, the enzyme’s activity has also been shown to influence sucrose phloem loading. One or multiple of these three processes contributes to plant freezing tolerance, among other abiotic stresses. Identifying the function(s) involved in freezing tolerance – through targeted knock out or rescue of individual functions – would facilitate more targeted manipulation ofAVP1in efforts to improve crop freezing tolerance. Thus far, we have confirmed the known freezing sensitive phenotype ofsfr5mutants, and identified similar sensitivity in the known AVP1 mutantfugu5-1. We aim to investigate the proton pumping, PPi hydrolysis and sucrose phloem loading functions in both mutants.

CP1.2 MOBILERNA: LOCATING MOBILE RNAS IN CROP GRAFTING USING

SRNASEQ AND MRNASEQ

Wednesday 5 July 2023 POSTER SESSION

Katie Jeynes-Cupper (University of Birmingham, United Kingdom), Marco Catoni (University of Birmingham, United Kingdom)

kej031@student.bham.ac.uk

In plants, systemic signalling is an elaborate molecular system that allows plants to coordinate development by integrating and transmitting information perceived from the environment to distant organs. Small RNAs (sRNAs) play an important role in long-distance signalling, where they are produced in one tissue and transported by the vascular system into recipient organs. Plant grafting systems have been used to study sRNA mobility and their implications on molecular mechanisms resulting in variation in plant physiology. These implications include changes to gene expression through post-transcriptional gene silencing via mRNA degradation, or alterations to DNA methylation patterns via the RNA-directed DNA methylation pathway. However, genomic study of sRNA movement between genotypes in a graft system lacks a standardized approach and an absence of resources to support the workflow or the presence of a streamline analysis pipeline. This results in a reduced confidence in the identification of mobile sRNA. Here, we introduce a novel R package,RNAlocate, which integrates the analysis, identification, and visualisation of sRNA movement between genotypes, starting from RNA sequencing experiments performed with the grafting of two genotypes. Most importantly, we show that the package is versatile across organisms and experimental designs, as well as, allowing targeted analysis of sRNA classes across multiple species.

DELPHINIDIN-3-O-GALACTOSIDE AND DELPHINIDIN-3-O-GLUCOSIDE

REVEALED BY GWAS

Wednesday 5 July 2023

POSTER SESSION

CP1.3 THE RELATIONSHIP BETWEEN THE GRAY, BLACK SEED COAT COLOR OF ADZUKI BEAN AND TWO ANTHOCYANINS

ORGANISED BY: DAVID EVANS (BOOKES UNIVERSITY), LIANA ACEVEDO-SIACA (MICHIGAN STATE UNIVERSITY), STEFAN KEPINSKI (UNIVERSITY OF LEEDS)

Xiaohan Wang (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)),

Kebede T Desta (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Yu-Mi

Choi (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Young-Ah

Jeon (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Sukyeung

Lee (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Myoung-Jae

Shin (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Joungyun

Yi (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South)), Hyemyeong Yoon (National Agrobiodiversity Center National Institute of Agricultural Sciences RDA, Korea (South))

wangxiaohan0530@gmail.com

Anthocyanins are important glycoside derivatives in plants. In response to biotic, abiotic stress, which have antioxidant, antibacterial, and photo-protective effects. In this study, two anthocyanins delphinidin-3O-galactoside (D-3-O-Ga) and delphinidin-3-O-glucoside (D-3-O-G) are found only in black and gray adzuki beans. Candidate genes for two kinds of anthocyanin content and seed coat color were obtained by GWAS. The heritability of D-3-O-G and D-3-O-Ga content was only 42.5% and 35.6%, respectively. The results of GWAS and haplotype analysis showed that a galactosyltransferase (UFGT) was retrieved on chr.10. Glycation of anthocyanidins by UFGT forms more stable anthocyanins, which are stored in the vacuole. Sequence differences in plant secondary product glycosyltransferase (PSPG) motif located at the C-terminus may result in the inability of UFGT mutants to specifically recognize specific anthocyanin aglycones. Another anthocyanin-related QTL and seed coat color associated region were mapped to chr.8, a 231kb overlap between two regions. Cytochromes P450 was scanned in this range. Cytochromes P450 determine the type of anthocyanin and impact the color by determining the number of hydroxyl groups on the B-ring of anthocyanidins, the more hydroxyl groups, the bluer the color. This study reveals the mechanism of anthocyanin biosynthesis in black and gray seed coat color adzuki bean, and explains the genetic background of the correlation between seed coat color precipitation and the type and content of anthocyanins during seed development. We will simulate the environment at different latitudes and observe the anthocyanin content of the seeds, the expression of related genes and the seed coat color changes.

PCR

Wednesday 5 July 2023 POSTER SESSION

Tae sung Park (National Institute of Agricultural Sciences, Korea (South)), Eunji Ga (National Institute of Agricultural Sciences, Korea (South)), Young-Soon Kim (National Institute of Agricultural Sciences, Korea (South)), Jea-In Lee (National Institute of Agricultural Sciences, Korea (South)), Soo In Sohn (National Institute of Agricultural Sciences, Korea (South)), Kong-Sik Shin (National Institute of Agricultural Sciences, Korea (South)), Youn sung Cho (National Institute of Agricultural Sciences, Korea (South)), Tae-Hun Ryu (National Institute of Agricultural Sciences, Korea (South))

jowon007@naver.com

As the development of living modified (LM) crops is increases globally, the European Union, South Korea and Japan strictly regulate the content of genetically modified (GM) DNA at 5%, 3% and 0.9% respectively. Quantitative real-time PCR (qRT-PCR) is a popular approach for counting the copy number of target genes in the LM crops. The effectiveness of the transgenic and the reference gene can be detected using the standard-curved qRT-PCR approach. In this experiment, we are starting with 200ng of 10% GM DNA, combined with non-LM and LM DNA, and constantly diluted four times. The unknown sample's Ct range for endogenous and event-specific primers was evaluated using a fivepoint scale. But, digital PCR (dPCR) directly counts DNA molecules and displays the quantity of DNA per unit volume. As a result, using the number of the target genes, we can precisely calculate the zygosity ratio. To appropriately analyze potential samples quantitatively, copy number is converted to weight using the zygosity ratio as a conversion factor. Hence, we decided to accurately quantify the contents of weight-based recombinant DNA by employing both qRT-PCR and dPCR methods. The zygosity ratio from the dPCR was intended to be mirrored in the qRT-PCR in this investigation. As a result, a little amount of GM DNA that was mixed with non-GM DNA was isolated and quantified using these methods. Our findings suggested that these combination techniques will be effective deterrents against GM DNA contamination in the crops.

CP1.5 TURNING METABOLISM INTO PATTERNS: THE MECHANISM BEHIND GIBBERELLIN GRADIENT IN ARABIDOPSIS ROOTS

Wednesday 5 July 2023 POSTER SESSION

Annalisa Rizza (Sainsbury Laboratory University of Cambridge (SLCU), United Kingdom), Markus Owen (School of Biosciences and School of Mathematical Sciences University of Nottingham, United Kingdom), Leah Band (School of Biosciences and School of Mathematical Sciences University of Nottingham, United Kingdom), Alexander M Jones (Sainsbury Laboratory University of Cambridge (SLCU), United Kingdom)

Annalisa.Rizza@slcu.cam.ac.uk

In Arabidopsis roots, cell division and elongation are separated into distinct longitudinal zones, and the growth regulatory hormone gibberellin (GA) influences both division and elongation. Our data using a genetically encoded fluorescent biosensor, nlsGPS1, showed that GA distributes in a longitudinal gradient with low levels in the meristematic zone increasing to a maximum at the end of the elongation zone. Using a mathematical modelling approach in combination with high-resolution gibberellin measurements and perturbations in vivo, we also showed how differentials in several biosynthetic enzyme steps contribute to the gibberellin gradient. We have now identified a link between the primary metabolite 2-oxoglutarate and the activity of GA biosynthetic enzymes in the central part of root meristem where the concentration of 2-oxoglutarate is limiting for GA biosynthesis. If the 2-oxoglutarate concentrations dynamically regulate other 2-oxoglutarate dependent (2-ODD) enzymes, this would affect myriad enzymatic reactions, cell signalling and metabolism processes in many organisms.

CP1.4 DIGITAL

AND REAL-TIME PCR AS EFFECTIVE TOOLS FOR QUANTIFICATION OF LIVING MODIFIED CROPS

CP1.6 BIO-UTILITIES OF QUANTUM DOTS IN CRISPR/CAS: FUNCTIONALIZATION OF Q-DOTS ON REPORTER PLASMID FOR DELIVERY IN PLANT TISSUE.

Wednesday 5 July 2023 POSTER SESSION

Asif Islam (Punjab Agricultural University, India), Tanmay Garde (Punjab Agricultural University, India)

asifislam20012@gmail.com

Conventional Agrobacterium mediated gene transfer is rarely 10-20 % efficient in transferring the candidate gene, can only target the nuclear genome and results in random DNA integration and constitutive expression which may disrupt endogenous plant genes and limits temporal control over transgene expression. Biolistic delivery of DNA using gold particles involves a high pressure gene gun and relies on physical disruption of the plant cell wall and membranes which can yield tissue damage and multiple transgene insertion into random portions of the plant genome. with both delivery methods, integration of transgenic DNA into plant genome triggers GMO labelling of the transformed plant, if it is to be sold as a consumable: largely subject to GM regulatory purview. Pay-loading of reporter gene carrying plasmid on functionalized Quantum dots can be an efficient way to transfer the candidate gene. This produces an enticing opportunity to combine nanotechnology delivery approaches with genome-editing tools.

CP1.7 UNDERSTANDING THE FUNCTIONAL RELEVANCE OF RECEPTOR KINASE INTERACTIONS WITH THEIR MEMBRANE ENVIRONMENT – BRI1 A

Wednesday 5 July 2023

POSTER SESSION

Silu Li (Silu Li, United Kingdom)

2437804@dundee.ac.uk

Plant receptor kinases (RKs) are cell surface receptors that bind to ligands in extracellular and play a key role in important biological processes like growth, development, differentiation, and immune response. S-acylation is a common post-translational modification of cysteine residues and has wide-ranging roles in plants. S-acylation of an important RK, FLS2, has been verified as crucial for its function in defense mechanisms (1). BRI1, another RK, is a central player in the brassinosteroid signaling cascade, which plays important roles in regulating plant growth and development and has also been shown S-acylated (2). However, the roles of S-acylation in BRI1 function have not yet been characterized. To investigate the S-acylation sites of BRI1, five single mutants and higher order combinations lacking cytoplasmic cysteines were generated. However, BRI1s from all mutants remained S-acylated. Although we failed to abolish S-acylation of BRI1 or identify specific sites, its existence in vivo was confirmed by testing for increase in S-acylation following ligand perception. This mirrors previous research that S-acylation of FLS2 occurs upon perception of its ligand in a BAK1 co-receptor dependent manner (1). We then turned our attention to the complex to see if novel components of BRI1 complexes are related to S-acylation. We are using novel copolymers to extract complex in a native membrane environment and identify components using MS. For future proteomics analysis, we

are verifying a complex containing at least BRI1 and BAK1 can be extracted by SMA buffer using Co-IP, as the interaction of BRI1 and BAK1 is well established.

CP1.8 INHIBITION OF CELLULAR SENESCENCE HALLMARKS BY MITOCHONDRIAL TRANSPLANTATION IN SENESCENCE-INDUCED ARPE-19 CELLS

Wednesday 5 July 2023

POSTER SESSION

Jeong Hun Kim (Seoul National University Hospital, Korea (South)), Sung-Eun Noh (Seoul National University Hospital, Korea (South))

steph25@snu.ac.k

Retinal pigment epithelium (RPE) damage is a major factor in age-related macular degeneration (AMD). The RPE in AMD shows mitochondrial dysfunction suggesting an association of AMD with mitochondrial function. Therefore, exogenous mitochondrial transplantation for restoring and replacing dysfunctional mitochondria may be an effective therapeutic strategy for AMD. Here, we investigated the effects of extrinsic mitochondrial transplantation on senescenceinduced ARPE-19 cells. We demonstrated mitochondrial dysfunction in replicative senescence-induced ARPE-19 cells after repeated passage. Imbalanced mitophagy and mitochondrial dynamics resulted in increased mitochondrial numbers and elevated levels of mitochondrial and intracellular reactive oxygen species. Exogenous mitochondrial transplantation improved mitochondrial dysfunction and alleviated cellular senescence hallmarks, such as increased cell size, increased senescence-associated β-galactosidase activity, augmented NF-κB activity, increased inflammatory cytokines, and upregulated the cyclindependent kinase inhibitors p21 and p16. Further, cellular senescence properties were improved by exogenous mitochondrial transplantation in oxidative stress-induced senescent ARPE-19 cells. These results indicate that exogenous mitochondrial transplantation modulates cellular senescence and may be considered a novel therapeutic strategy for AMD.

CP1.9 CALCAROIDES-C AS A TOOL FOR INVESTIGATING 3D SHAPE REGULATION

Wednesday 5 July 2023 POSTER SESSION

Jonathan Lecoy (University of Edinburgh, United Kingdom), Annis Richardson (University of Edinburgh, United Kingdom)

j.g.t.lecoy@sms.ed.ac.uk

Calcaroides-C (Cal-C) is a dominant barley mutant, in which the lemma develops ectopic novel sac-like and wing-like structures at the lemmaawn transition zone. Our analysis of the Cal-C phenotype shows that while Cal-C does not affect barley vegetative growth it does slow down inflorescence development. We also found a phenotypic gradient along the Cal-C inflorescence. Analysis of cell shape, also found that changes in lemma shape were preceded by changes in cell shape in the Cal-C lemma epidermis. Using a lemma-specific RNAseq analysis, we have identified an upregulation of HvKNOX8 and propose that this may underlie the Cal-C phenotype, by causing changes in the expression of abaxial patterning genes YABBY15 and KANADI1.

CP1.10 ATR-FTIR SPECTROSCOPYLINKED CHEMOMETRICS: A NOVEL APPROACH TO THE ANALYSIS AND CONTROL OF THE INVASIVE SPECIES JAPANESE KNOTWEED

Wednesday 5 July 2023 POSTER SESSION

Claire A Holden (Lancaster University, United Kingdom)

c.holden6@lancaster.ac.uk

Background: Invasive Japanese knotweed (Reynoutria japonica), causes negative environmental and socio-economic impacts. A female clone in the United Kingdom, its extensive rhizome system enables rapid vegetative spread. Plasticity permits this species to occupy a broad geographic range and survive harsh abiotic conditions. It is notoriously difficult to control with traditional management strategies, which include repetitive herbicide application and costly carbon-intensive rhizome excavation. This problem is complicated by crossbreeding with closely related species leading to misidentification.

Methods: Advances in the application of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy linked chemometrics within plant sciences allow opportunities for the identification and control of knotweed, to enhance our understanding of knotweed biology, and to explore the potential of this technique. Analysis of ATR-FTIR spectral profiles of Japanese knotweed leaf material and xylem sap samples provide information about important biological absorptions due to lipids, proteins, carbohydrates, and nucleic acids.

Results: Technical advances were made for the application of ATR-FTIR spectroscopy to plant science, including definition of the environmental factors that exert the most significant influence on spectral profiles, evaluation of sample preparation techniques, and identification of key wavenumbers for prediction of hormone concentrations and abiotic stress. Results include successful identification of plants from different growing regions which highlights the plasticity of this clonal species; differentiation between related species and hybrids; and prediction of key physiological characteristics, such as hormone concentrations and root water potential. This techinique promises to be a powerful approach for the study of plant biology.

CP1.11 THE MAIZE FUSED LEAF 1 MUTANT

Wednesday 5 July 2023

POSTER SESSION

Heather Jones (University of Edinburgh, United Kingdom), Emily Lyon (University of Edinburgh, United Kingdom), Katie Long (University of Edinburgh, United Kingdom), Alice Gevorgyan (USDA Plant Gene Expression Center, United States), Amber De Neve (University California Berkeley, United States), Sarah Hake (USDA Plant Gene Expression Center, United States), Annis Richardson (University of Edinburgh, United Kingdom)

heather.hfj@gmail.com

The world’s population is predicted to reach nearly 10 billion in the next three decades, and in order to feed this growing population without encroaching on Earth’s remaining wild areas, agricultural productivity desperately needs to increase. While novel agricultural techniques such

as indoor and vertical farming are a key development towards this goal, focus must also be on the crops themselves, to best maximise their yield. To do so requires a greater understanding of the networks underpinning their development, including, principally, the formation and development of their organs; this is especially poignant in cereal crops such as maize and rice, which are the largest source of global calories and yet are broadly understudied compared to their eudicot relatives. One way to find genes important for organ development is through mutant analysis. A fundamental step in organ development is the separation of the differentiating organ cells (primordium) from the pool of stem cells (meristem) through the formation of a boundary. Here we present a new mutant in maize in which the boundary between initiating leaf primordia and between primordia and the meristem is defective, called fused leaf 1.

CP1.12 DESIGNING OPTIMAL EXPRESSION SYSTEMS FOR THE PRODUCTION OF RECOMBINANT PROTEINS IN PLANTS

Wednesday 5 July 2023 POSTER SESSION

Ryan J Coates (Cardiff University, United Kingdom), Simon Scofield (Cardiff University, United Kingdom), Mark T Young (Cardiff University, United Kingdom)

CoatesRJ@cardiff.ac.uk

Plants have great potential for the expression of recombinant proteins. They are able to produce complex post-transcriptionally modified proteins that are unobtainable using prokaryotic production systems, with unprecedented upstream scalability resulting in dramatically reduced costs relative to eukaryotic cell cultures. Transient protein expression dramatically reduces the time taken between transformation events and recombinant protein extraction and purification, however low protein yields relative to conventional expression systems remain a major drawback, with only limited success in addressing this in recent years. Here, through combining several published genetic components, we have developed a plant protein expression construct that achieves exceptionally high protein expression levels. Using GFP as a reporter, we quantified in planta fluorescence by photon imaging, transcript copy number by qRT-PCR, and protein levels by western blotting as metrics for expression. We anticipate that this expression construct will be a useful tool for improved plant recombinant protein production and believe it can serve as a basis for improved expression systems in the future.

CP1.13 THE STE20-LIKE KINASE

Wednesday 5 July 2023 POSTER SESSION

Si GU (Liverpool John Moores University, United Kingdom), Yu XING (Beijing University of Agriculture, China), Baoxiu QI (Liverpool John Moores University, United Kingdom)

s.gu@2020.ljmu.ac.u

One of the main marketing preferences of strawberry (Fragaria vesca) is its fruit size. Organ size control is complicated yet highly coordinated

FVM4K1 REGULATS ORGAN SIZE IN STRAWBERRY (FRAGARIA VERCA.)

involving various signalling molecules and pathways of which the Hippo signalling pathway is the key regulator. This pathway was also identified from the budding yeast where the main component Ste20 plays vital role in cell division. Here, we report the identification of an Ste20-like protein, FvM4K1 from strawberry. It partially rescued the bipolar bud site selection and mitotic exit defect of the yeast mutant ste20Δ and also complement Arabidopsis mutants atsik1s that are lacking AtSIK1, the Ste20-like proteins. Down regulation of FvM4K1 by RNAi results in dwarfed strawberry plants with much smaller vegetative and reproductive organs due to reduced cell size and numbers as observed in the leaves and petals. These results demonstrate that FvM4K1 is most likely the homolog of Ste20.

FvM4K1 but not the kinase-dead pointed mutant FvM4K1K269E was auto-phosphorylated. FvM4K1 can phosphorylate as well as interact with the two FvMOB1A&1B, the homologs of Mats/Mob1 of the Hippo pathway. The interactions between FvM4K1 and FvMOB1s were further confirmed by bimolecular fluorescence complementation where the N-terminal domain of M4K1 was shown to be essential for this interaction. These combined results indicate that the FvM4K1, FvMOB1A&1B belong to and play similar roles in the Hippo pathway in strawberry.

Taken together, strawberry FvM4K1 functions as the main component of the Hippo signalling pathway. Via phosphorylating FvMOB1s FvM4K1 plays essential roles in organ size control in strawberry.

CP1.14 DEVELOPMENT OF STEMS’ WATER MONITORING SYSTEM USING LOW-COST TECHNOLOGIES FOR EARLY DETECTION OF XYLELLA FASTIDIOSA IN OLIVE TREES

Wednesday 5 July 2023

POSTER SESSION

Nikolaos M. Polymenakos (Ionian University, Greece), Markos Avlonitis (Ionian University, Greece), Ioannis Karydis (Ionian University, Greece), Vojsava Gjoni (University of South Dakota, United States), Nikolaos Avgoustis (Ionian University, Greece), Evangelos Alvanitopoulos (Ionian University, Greece)

polymenakos@ionio.gr

Water monitoring inside a tree trunk is particularly important because it can provide useful information about the crops’ health. Although, in most cases of water monitoring aim to access water stress and transpiration rate in trees, we have used it to access a catastrophic tree disease. Specifically, we have developed an innovative system to monitor the stems’ water at the early stage of Xylella fastidiosa in olive trees (Olea europaea). The proposed system has been tested in real-life conditions using sensors installed on three branches of an olive tree. We tested the periodicity of water percentage per day across healthy vs infected branches. Specifically, in a healthy olive tree, the sensor recorded a significant percentage of fluids inside the trunk, even in its driest instances. The equivalent recordings on an infected tree had significantly lower water percentages. In conclusion, the proposed method offers the ability to assist cultivators in observing in almost real-time if trees contain sufficient levels of water inside their trunk, or if there is a decrease such as Xylella fastidiosa that may damage the health of the tree. The system we used is a low-cost technology and for this reason can provide lots of benefits in terms of further upgrade and maintenance. In addition, due to its low construction cost, it can contribute to the development of a network of sensors to support dense coverage of crops.

CP1.15 MULTIFACETED FUNCTION OF ARABIDOPSIS G PROTEIN Β SUBUNIT, AGB1, IS CONFERRED BY ITS FOUR ALTERNATIVE SPLICE ISOFORMS

Wednesday 5 July 2023 POSTER SESSION

Yueh Cho (Institute of Plant and Microbial Biology Academia Sinica, Taiwan)

choyueh@gate.sinica.edu.tw

The Arabidopsis heterotrimeric G protein β subunit, GTP BINDING PROTEIN BETA 1 (AGB1), has multiple functions in plant development and response to various environmental stimuli including endoplasmic reticulum (ER) stress. However, how the single gene produces the pleiotropic effect remains elusive. Here, we show that AGB1 has 4 alternative splice isoforms with isoform-specific features. AGB1.2 failed to rescue the agb1-3 mutant defects and thus was considered a non-functional isoform. Although AGB1.1 and AGB1.4 were both localized at the plasma membrane and the ER, AGB1.1 fully rescued the defects of agb1-3 and AGB1.4 only partially rescued the defects even though its transcript level was higher than that of AGB1.1. Intriguingly, AGB1.3 was localized at the nucleus and further enhanced the leaf shape phenotype of agb1-3. The protein structure of AGB1.3 is unique because of the termination of translation in the 7th-WD40 motif by alternative splicing, which produced an incomplete propeller structure. AGB1.1 and AGB1.4 but not AGB1.3 interacted with the Gγ subunits, AGG1, AGG2, and AGG3, possibly because of lack of the 7th-WD40 motif in AGB1.3. AGB1 may produce its multifaceted functions in plant development and ER stress tolerance via its alternative splice isoforms with distinct structural features and subcellular localization.

CP1.16 DEVELOPMENT OF STEMS’ WATER MONITORING SYSTEM USING LOW-COST TECHNOLOGIES FOR EARLY DETECTION OF XYLELLA FASTIDIOSA IN OLIVE TREES

Wednesday 5 July 2023

POSTER SESSION

Nikolaos M. Polymenakos (Ionian University department of Informatics, Greece), Markos Avlonitis (Ionian University department of Informatics, Greece), Ioannis Karydis (Ionian University department of Informatics, Greece), Vojsava Gjoni (University of South Dakota, United States), Nikolaos Avgoustis (Ionian University department of Informatics, Greece), Evangelos Alvanitopoulos (Ionian University department of Informatics, Greece)

polymenakos@ionio.gr

Water monitoring inside a tree trunk is particularly important because it can provide useful information about the crops’ health. Although, in most cases of water monitoring aim to access water stress and transpiration rate in trees, we have used it to access a catastrophic tree disease. Specifically, we have developed an innovative system to monitor the stems’ water at the early stage of Xylella fastidiosa in olive trees (Olea europaea). The proposed system has been tested in real-life conditions using sensors installed on three branches of an olive tree. We tested the periodicity of water percentage per day across healthy vs infected branches. Specifically, in a healthy olive tree, the sensor

recorded a significant percentage of fluids inside the trunk, even in its driest instances. The equivalent recordings on an infected tree had significantly lower water percentages. In conclusion, the proposed method offers the ability to assist cultivators in observing in almost real-time if trees contain sufficient levels of water inside their trunk, or if there is a decrease such as Xylella fastidiosa that may damage the health of the tree. The system we used is a low-cost technology and for this reason can provide lots of benefits in terms of further upgrade and maintenance. In addition, due to its low construction cost, it can contribute to the development of a network of sensors to support dense coverage of crops.

CP1.17 DIRECT METABOLITE PROFILING OF RICE POLLEN EXUDATES WITH PICOLITRE PRESSURE-PROBE ELECTROSPRAY-IONIZATION MASS SPECTROMETRY

Wednesday 5 July 2023 POSTER SESSION

Hiroshi Wada (Ehime University, Japan), Yuto Hatakeyama (Ehime University, Japan), Rosa Erra-Balsells (University of Buenos Aires, Argentina), Hiroshi Nonami (Ehime University, Japan), Takuya Araki (Ehime University, Japan), Yoko Yamaga-Hatakeyama (Ehime University, Japan)

hwada@agr.ehime-u.ac.jp

Different from the most flowering plants whose pollen grains are dehydrated and metabolically inactive prior to landing on the stigma, rice-like grass plants exhibit partially hydrated pollen grains that retain metabolic activity at pollen release from dehiscent anther. Shortly after the pollen grains land onto the stigma, picolitre liquid exudation occurs from the pollen surface, termed ‘pollen exudation’, leading to germination. This site-specific event associated with pollen vigour might be the key to determine the pollination success in grass; however, little is known about the physiological event because of the rapid phenomenon at nanolitre scale. We used picolitre pressure-probe electrospray-ionisation mass spectrometry (picoPPESI-MS) to directly assay the exudates in intact ‘Koshihikari' plants, in comparison with fluids collected from mature pollen grains and stigma papilla cells at the same stage. Considerable spatial variations in metabolites have been observed between three fluids with high reproducibility. Sugars, organic acids, proline, cell wall-related metabolites, ascorbate and hexose phosphate were shown to be contained in mature pollen grains, whereas sugars and flavonoids were detected in stigma cells. Contrastingly, high concentration of sugars, ascorbate, monoascorbate, glutathione, proline, and fatty acids was detected in the exudates. Because pollen exudation precedes pollen adhesion to cause pollen hydration in rice, it is suggested that these chemicals contained in exudates would participate in rapid pollen foot formation, optimising the pollination process. Further application of this analytical method may provide new insights into the metabolic control at pollination under severe stress conditions, such as heat.

CP1.18 EXPLORING LINKS BETWEEN RNA REGULATION AND ANTIBIOTIC RESISTANCE: PENICILLIN-BINDING PROTEIN 2A IS A NOVEL RNA-BINDING PROTEIN IN METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS

Wednesday 5 July 2023 POSTER SESSION

Niki Christopoulou (The University of Edinburgh, United Kingdom), Sander Granneman (The University of Edinburgh, United Kingdom)

n.christopoulou@sms.ed.ac.uk

For pathogenic bacteria to survive their often hostile habitats, they need to overcome numerous challenges, such as changes in nutrient availability, temperature alterations, exposure to the host environment and antibiotic stress. Using RNA-binding proteins (RBPs), they can very quickly adjust their gene expression, to counteract these stresses. In methicillin resistant Staphylococcus aureus (MRSA), the cell wall biosynthesis enzyme penicillin binding protein 2a (PBP2a) is a key determinant of antibiotic resistance. Our recent findings suggest that PBP2a also serves as an RNA-binding protein. Using UV cross-linking and analysis of cDNAs (CRAC), hundreds of RNAs were found to interact with PBP2a in vivo, with in vitro assays also confirming the RNA-binding activity of the enzyme. What is the significance of this RNA-binding function? Our goals are to study the role of the interactions between PBP2a and its target RNAs, to determine whether these interactions contribute to the antibiotic resistance mechanisms of MRSA and to discover potential novel therapeutic approaches to combat the lifethreatening infections that MRSA can cause.

CP1.19 DIGITAL PCR AND REALTIME PCR AS EFFECTIVE TOOLS FOR QUANTIFICATION OF LIVING MODIFIED CROPS

Wednesday 5 July 2023 POSTER SESSION

Tae sung Park (National Institute of Agricultural Sciences (NIAS), Korea (South)), Eunji Ga (National Institute of Agricultural Sciences (NIAS), Korea (South)), Young-Soon Kim (National Institute of Agricultural Sciences (NIAS), Korea (South)), Jea-In Lee (National Institute of Agricultural Sciences (NIAS), Korea (South)), Soo In Sohn (National Institute of Agricultural Sciences (NIAS), Korea (South)), Kong-Sik Shin (National Institute of Agricultural Sciences (NIAS), Korea (South)),

Youn-Sung Cho (National Institute of Agricultural Sciences (NIAS), Korea (South)), Tae-Hun Ryu (National Institute of Agricultural Sciences (NIAS), Korea (South))

jowon007@naver.com

As the development of living modified (LM) crops is increases globally, the European Union, South Korea and Japan strictly regulate the content of genetically modified (GM) DNA at 5%, 3% and 0.9% respectively. Quantitative real-time PCR (qRT-PCR) is a popular approach for counting the copy number of target genes in the LM crops. The effectiveness of the transgenic and the reference gene can be detected using the

standard-curved qRT-PCR approach. In this experiment, we are starting with 200ng of 10% GM DNA, combined with non-LM and LM DNA, and constantly diluted four times. The unknown sample's Ct range for endogenous and event-specific primers was evaluated using a fivepoint scale. But, digital PCR (dPCR) directly counts DNA molecules and displays the quantity of DNA per unit volume. As a result, using the number of the target genes, we can precisely calculate the zygosity ratio. To appropriately analyze potential samples quantitatively, copy number is converted to weight using the zygosity ratio as a conversion factor. Hence, we decided to accurately quantify the contents of weight-based recombinant DNA by employing both qRT-PCR and dPCR methods. The zygosity ratio from the dPCR was intended to be mirrored in the qRT-PCR in this investigation. As a result, a little amount of GM DNA that was mixed with non-GM DNA was isolated and quantified using these methods. Our findings suggested that these combination techniques will be effective deterrents against GM DNA contamination in the crops.

CP1.20 FRET-BASED SENSORS TO MONITOR THE OSMOTIC PRESSURE DURING MICRO-TISSUE FORMATION

Wednesday 5 July 2023 POSTER

Efe Cuma Yavuzsoy (Max Planck Institute of Colloids and Interfaces, Germany), Wenbo Zhang (Max Planck Institute of Colloids and Interfaces, Germany), Richard Weinkamer (Max Planck Institute of Colloids and Interfaces, Germany), Cécile Bidan (Max Planck Institute of Colloids and Interfaces, Germany), Peter Fratzl (Max Planck Institute of Colloids and Interfaces, Germany)

efe.yavuzsoy@mpikg.mpg.de

Besides biochemical signalling, mechanical forces play a crucial role in modulating cell behaviour in tissue formation. Forces are transmitted to cells typically via the self-produced extracellular matrix (ECM). The forces can originate not only from an external loading, but can be also internally created by the action of osmotic effects. It was shown that osmotic pressure can produce substantial tensile stresses in collagen-based tissues. To understand the role of osmotic effects on tissue formation, we developed in previous research work dye-loaded liposome-based osmotic pressure sensors. The working principle of these sensors is a shape change of the liposomes in response to a change in osmotic pressure, which can be read out as a distance change between the dyes based on FRET (Forster resonance energy transfer). In the current study, we apply these sensors in a cell culture experiment with the aim to monitor changes of osmotic pressure during tissue formation. We used MCT3T3-E1 pre-osteoblast cell line (seeding density 105 cells/cm2 ) in multi-well plates. To measure the FRET signal, fluorescent and confocal microscopy were used and images were taken every 3-4 days over several weeks. After each imaging, cell medium was changed and new sensors were added to the medium. The images were evaluated in terms of mean intensities and intensity distributions with a self-written Matlab code. Knowing the osmotic pressure while new ECM is forming will provide information about a possible mechanical interaction between the formed ECM and cells.

CP1.21 REPEATED TREATMENT WITH ANTIMALARIAL AGENTS CAUSES INVITRO LIVER CELL TOXICITY

Wednesday 5 July 2023 POSTER SESSION

David Audu (Federal University of Agriculture Abeokuta Nigeria., Nigeria), Vinood B Patel (University of Westminster, United Kingdom), Lucy Petagine (University of Westminster, United Kingdom), Olufunmilayo A Idowu (Federal University of Agriculture Abeokuta, Nigeria), Adewumi B Idowu (Federal University of Agriculture Abeokuta, Nigeria)

audud@funaab.edu.ng

In Africa’s malaria-endemic regions, artesunate/amodiaquine (A/A) and artemether/lumefantrine (A/L) are the antimalarial medications that are most frequently prescribed. Antimalarial medications could be overused if they are self-prescribed based on symptoms rather than a parasitological diagnosis. This investigation looked at potential cytotoxic and oxidative stress effects following three dosage treatments spaced 24 h apart. Artesunate (50 μM and 100 μM), Amodiaquine (1 μM and 10 μM), Artemether (200 μM and 400 μM), and Lumefantrine (200 μM and 400 μM) were administered to HepG2-derived VL-17A for up to 72 h. With a downward trend from 24 h to 48 h to 72 h, the study findings showed that repeated administration of these medications greatly reduced cell viability. Additionally, for artemether 200 μM treatment, the reactive oxygen species (ROS) levels increased after 24 h and 48 h but considerably decreased after 72 h. The ROS levels in artesunate, amodiaquine, artemether 400 μM, and lumefantrine were also noticeably lower after 72 h. The results of this experiment show that repeated applications of the constituents of A/L and A/A to HepG2 liver cells reduced their viability in a manner that was consistent. These findings have significant implications for those who use antimalarial medications as a preventative measure without a diagnosis of parasite infection.

CP1.22 UNRAVELLING THE OCCURRENCE AND FUNCTION OF THE UNUSUAL ANTIOXIDANTS ERGOTHIONEINE AND OVOTHIOL IN PLANTS AND PHOTOSYNTHETIC PROTISTS

Wednesday 5 July 2023

POSTER SESSION

Nicholas Smirnoff (University of Exeter, United Kingdom), Isobel Cole (University of Exeter, United Kingdom), Glen Wheeler (The Marine Biological Association, United Kingdom), Katherine Helliwell (University of Exeter, United Kingdom), Deborah Salmon (University of Exeter, United Kingdom)

n.smirnoff@exeter.ac.uk

Ergothioneine and ovothiol are histidine derived sulfur containing metabolites. The occurrence of ergothioneine has been[SN1] well described in fungi and bacteria and ovothiol in bacteria, diatoms, and sea urchins. These compounds may play a role in protection against environmental stresses. Similarities to compounds such as glutathione and betaines suggest potential roles as an antioxidant and osmolyte. There is currently limited knowledge on their occurrence, synthesis, and physiological functions in plants and photosynthetic protists,

so we have carried out a comprehensive survey of their occurrence. Ergothioneine was detected in all phyla within the Archaeplastida except for most spermatophytes, with highest concentrations in the Streptophytes. Ovothiols were detected at low levels inCyanophora paradoxaand in the Chlorophytes and Rhodophytes[CI2] , but they were not detected in the Streptophytes. The occurrence of each compound is also supported by the presence of genes encoding a methyltransferase (EgtD, Egt1, OvoA)[CI3] , FGE-sulfatase (EgtB, Egt1, OvoA) and aminotransferase (EgtE, Egt2, OvoB), predicted ergothioneine and ovothiol biosynthesis enzymes, confirming the ability to synthesise ergothioneine and ovothiol. The spores of the ferns and bryophytes show an elevated concentration of ergothioneine compared to their vegetative[SN4] tissue, suggesting a potential role in reproduction and spore viability under stressful conditions. The function of ergothioneine and ovothiols is being investigated by production of ergothioneine deficientMarchantia polymorpha(a bryophyte) and ovothiol B deficient Phaeodactylum tricornutum (a diatom) mutants.

CP1.23 STRATEGIES FOR PRESERVING AND SHARING DATA IN BIOLOGICAL SCIENCES

Wednesday 5 July 2023

POSTER SESSION

Livia C T Scorza (University of Edinburgh, United Kingdom), Tomasz Zieliński (University of Edinburgh, United Kingdom), Andrew J Millar (University of Edinburgh, United Kingdom) livia.scorza@ed.ac.uk

Managing and sharing research data is not always a simple task. The diversity of data types in biology, the lack of standard practices in data management, data storage and preservation issues, and, perhaps most importantly, the lack of awareness on the matter, are some of the factors that prevent research outputs being made available routinely and in a reusable way. The FAIR (Findable, Accessible, Interoperable, Reusable) principles were published as a general guidance to promote data reusability in research, but the practical implementation of FAIR principles in research groups is still falling behind. Here we will show how our Biological Research Data Management team assists experimental researchers with organizing datasets for publication by using different types of tools and web resources to maximize data reusability, while maintaining research productivity. We will showcase practical examples from data curation to data sharing, and how we promote awareness of FAIR and Open Science in biological sciences.

CP1.24 ELUCIDATING HOW ROS PRODUCTION, PROTEIN OXIDATION AND ATP DEPLETION CONTRIBUTE TO SELF-INCOMPATIBILITY

Wednesday 5 July 2023 POSTER SESSION

Nicholas Smirnoff (University of Exeter, United Kingdom), Ludi Wang (University of Aberystwyth, United Kingdom), Anshan Hsiao (University of Exeter, United Kingdom), José Carli (University of Aberystwyth, United Kingdom), Vernonica Franklin-Tong (University of Birmingham, United Kingdom), Maurice Bosch (University of Aberystwyth, United Kingdom

n.smirnoff@exeter.ac.uk

Many plants utilize self-incompatibility (SI) to prevent pollen tube growth on the “wrong” pistil, thereby preventing self-fertilization. In poppy, the interaction of a “receptor” (PrpS) with a stigma-derived protein (PrsS), rapidly triggers an increase in cytosolic Ca2+ , increased reactive oxygen species (ROS), cytosolic acidification, a decrease in ATP and changes in actin organisation which integrate to activate proteases, leading to eventual programmed cell death (PCD). PrpS and PrsS expression in normally self-fertile Arabidopsis thaliana introduces a functional SI system enabling the use of genetic tools to dissect the SI response. To investigate ROS production in more detail we introduced the H2 O2 probe roGFP-Orp1 using a pollen-specific promoter and targeted it to the cytosol, mitochondria, plastids and peroxisomes. SI induction causes but a rapid decrease in extracellular tip localised superoxide production coincident with growth inhibition, and an increase in probe oxidation in cytosol, mitochondria and plastids. The ATP biosensor ATeam was used to visualise ATP depletion during the SI response. Rapid oxidation of the glycolytic enzyme glyceraldehyde 3-P dehydrogenase was detected in a proteomics experiment 10 min after SI and H2 O2 treatment; this is associated with a rapid decrease in its activity and an associated decrease in pollen respiration rate. Our data indicate roles for intracellular organelle-specific oxidation in the early stages of the poppy SI response. We are currently investigating how the oxidative events, ATP depletion and cytosolic acidification interact to trigger PCD.

CP1.25 PHYTOPHTHORA CAPSICI NMRA-LIKE PROTEIN FAMILY: ORCHESTRATORS OF DEVELOPMENT AND VIRULENCE?

Wednesday 5 July 2023 POSTER SESSION

Rafael Monteiro do Carmo (University of Dundee James Hutton Institute, United Kingdom), Paul Birch (University of Dundee James Hutton Institute, United Kingdom), Edgar Huitema (University of Dundee James Hutton Institute, United Kingdom)

2473491@dundee.ac.uk

Population growth drastically increases the demand for food. Minimizing losses caused by pathogens is one approach to increasing yields. The oomycetes comprise a significant group of pathogens of economic and ecological importance. For example, the oomycete pathogen Phytophthora capsici attacks a wide range of crops, including

tomato, pepper, cucurbits and others. Thus, a comprehensive control strategy, applicable to multiple crops, might greatly improve vegetable production. Such strategies, however, require a detailed understanding of pathogen biology. Therefore, our group has been investigating P. capsici biology, showing a distinct and tightly controlled gene expression during the biotrophic and necrotrophic phase that appears regulated by PcNMRAL1. PcNMRAL1 overexpression in P. capsici extends the biotrophic phase, delaying necrotrophy. Whilst we know that PcNMRAL1 affects the expression of stage-specific genes, little is known about the role(s) of NmrA-like genes in P. capsici. Therefore, our aim is to understand the evolutionary history and functional role(s) of NMRA-like proteins in P. capsici. Computational identification and classification revealed 28 NMRA-like proteins in P. capsici that fall into six major groups, each of which features distinct distribution and gene expression patterns. Our work suggests distinct roles for NMRA-like proteins in Phytophthora and more generally, oomycete pathogenesis. Unraveling the mechanisms associated with phase switch could lead to novel and effective control strategies.

CP1.26 OOCYTE ACTIVATION AND DEVELOPMENT: ROLE OF PHOSPHOLIPASE C ENZYMES

Wednesday 5 July 2023 POSTER SESSION

Roshan Sahu (University of Oxford, United Kingdom)

roshansahumail@gmail.com

Background: Calcium oscillations are essential for the activation of the oocyte and a series of post-fertilization and development events. Phospholipase C zeta (PLCζ ) knockout greatly inhibits the majority of the Ca2+ oscillations confirming PLCζ's physiological importance (1). However, surprisingly, a few delayed Ca2+oscillations still occur in the absence of PLCζ , and these result in unexpected subfertility, not infertility. This suggests that PLCζ is not the sole factor to initiate Ca2+ oscillations in the oocyte and other factors are involved. This encouraged the exploration of other derived PLC isoforms & their potential roles in oocyte activation. Methods and Results: Qualitative and quantitative genetic and protein expression of PLC isoforms suggest many of the mammalian PLCs are expressed in gamete cells. qPCR identified significant changes in the expression of certain PLCs in PLCζ KO cells which makes them target PLCs to study in the context of fertilization. Our inhibitory analysis has also suggested potential roles for other PLCs in the activation of oocytes in the absence of PLCζ. Preliminary studies on WT and PLCζ KO blastocyst development suggest that the differences in the Ca2+ signal after fertilization in PLCζ's absence have an important impact on embryo development.

Conclusion: This suggests that other PLCs besides PLCζ may have an important role in the egg activation process. Ca2+ transients and oocyte activation that occur in PLCζ's absence after fertilization could be due to such PLCs.

AND DIVERSITY EDUCATION OUTREACH ABSTRACTS

OED2 - OUTREACH AND PE

ORGANISED BY: JORDAN MILLWARD (IMPERIAL COLLEGE LONDON), NICOLA VEITCH (UNIVERSITY OF GLASGOW)

OED2.1 INTEGRATING COMMUNITY ENGAGEMENT IN BIOLOGY CURRICULUM THROUGH CRITICAL THEORY

Thursday 6 July 2023 14:30

Josh A Hodge (Imperial College London, United Kingdom)

j.hodge@imperial.ac.uk

Critical theory offers a valuable framework for deconstructing systems of oppression and privilege in the production and dissemination of biological knowledge. In doing so, student’s gain a critical consciousness to challenge and resist the normativity in science and the society around them. However, much of these discussions remain in the ivory tower, sequestered to the classroom, discussed in abstraction, and divorced from the real people and lives normative ideologies impact. There is the danger of positivism and the assumption of parity in experience, which reduces student’s compassion and empathy. The integration of community engagement into biology curricula challenges this view of one-objective truth and presents plural experiences of systems of oppression and privilege and presents an avenue for social activism and change – a component lacking in academic environments. Drawing on educational research exposing heteronormativity in biological research, this presentation analyses and reflects on the discussions with students, offers practical tools and strategies for incorporating queer theory into biology as well as exploring the barriers of integrating community engagement/activism in biology curriculum.

OED2.2 COMMUNITY-ENGAGED LEARNING: AN APPROACH TO SUPPORT INSTITUTIONAL OUTREACH AND STUDENT UNDERSTANDING OF SOCIOSCIENTIFIC ISSUES

Thursday 6 July 2023 15:00

Sarah E.A. McLean (Western University, Canada)

sarah.mclean@schulich.uwo.ca

Science education programs tend to focus on content mastery. But scientific knowledge alone will not solve society's pressing problems, which require an understanding of how the scientific and the social intersect to impact people and communities. While some programs have begun implementing community-engaged learning into their curricula, little attention has been paid to how these partnerships support the understanding of complex social issues. As defined by Morton, Varghese & Thompson (2018), community-engaged learning (CEL) “is a teaching and learning pedagogy that meaningfully integrates community

engagement and curricular programming with intentional alignment between course learning outcomes and community-identified needs.” This presentation will outline how this learning approach has been successfully implemented in an undergraduate STEM program at both a course-level and a programmatic, co-curricular level. Students engaged in CEL courses can expand community partner capacity by supporting grant writing, performing data analysis, enhancing social media engagement, and performing literature reviews. By the end of this presentation, participants will be able to: 1) List effective CEL student engagement approaches, 2) Describe principles of effective community partnerships and 3) Outline best practices for curricular alignment and evaluation. Examples of project deliverables will also be shared.

OED2.3 PARASITE STREET SCIENCEAN ARTS AND SCIENCE PUBLIC ENGAGEMENT COLLABORATIVE PROJECT

Thursday 6 July 2023 15:15

Nicola J Veitch (University of Glasgow, United Kingdom), Walt Adamson (University of Glasgow, United Kingdom), Hannah Bialic (University of Glasgow, United Kingdom), Alan Richardson (Surge, United Kingdom), Karen Veitch (Surge, United Kingdom), Tiarna Meehan (University of Glasgow, United Kingdom), Janelisa Musaya (Kamuzu University of Health Sciences, Malawi), Lumbani Pete (Kamuzu University of Health Sciences, Malawi), Bwanalori Mwamlima (Health and Social Services Rumphi, Malawi), Garry Chilinga (Health and Social Services Nkhotakota, Malawi), John Alufandika (Voices Malawi, Malawi), Annette Macleod (University of Glasgow, United Kingdom)

Nicola.Veitch@glasgow.ac.uk

Sleeping sickness is a significant health issue in rural Africa. The disease, caused by trypanosome parasites and spread by tsetse flies, is fatal if left untreated. It is most prevalent in resource-poor settings often far from healthcare facilities, and initial presentation is similar to malaria. As a result, many cases go undiagnosed or present late in infection. Furthermore, misinformation and a lack of trust in scientists and healthcare professionals has often resulted in diagnosis and treatment not being sought.

The aim of Parasite Street Science was to provide a model for using performance theatre to stimulate discussion about research into sleeping sickness to enhance trust in scientists within affected communities in Malawi. The project created a new interactive street theatre performance which was piloted at a football match at Partick Thistle in Glasgow. After refining and modifying for a Malawi audience using Malawian music and collaborating with a professional theatre director, scientists, health promotion officers, clinicians, nurses, survivors of sleeping sickness, and Life Sciences students, it toured

sleeping sickness endemic areas, putting on six performances, where invited audiences from affected communities to actively participate in an enjoyable and fun event. Following performances, local community radio was used to widen the reach of the work, with phone in Q&A sessions taking place with local scientists from Malawi answering questions relating to sleeping sickness. Digital resources, including a web site, videos of the performance and interviews with participants have been developed to ensure a tangible legacy of the work.

OED2.4 CO-DEVELOPING OCEAN LITERACY AND INVASIVE SPECIES MONITORING THROUGH AN ONLINE CITIZEN SCIENCE PLATFORM

Thursday 6 July 2023 15:45

Leon Green (University of Gothenburg, Sweden), Victor Anton (Wildlife.ai, New Zealand),

Linnéa Svensson (University of Gothenburg, Sweden), Jannes Germishuys (Combine, Sweden), Diewertje Dekker (Combine, Sweden), Emil Burman (University of Gothenburg, Sweden), Matthias Obst (University of Gothenburg, Sweden)

leon.green@bioenv.gu.se

Digital online tools for outreach can reach a large audience, but it is rare that they are interactive while also feeding the scientists data valuable to their research. We have developed an online image classification platform to identify animals from underwater video. This platform is mainly designed to tackle the problem of monitoring an invasive species on the Swedish west-coast. As invasive species are great examples of direct threats to the local environment, the monitoring becomes a unique challenge that the participants in the project can help to solve. As participants collect data as citizen scientists, the public outreach on the issue of invasive species becomes more engaging. Though the project doesn’t have a formal target audience, it is aligned with a local endeavor to promote ocean literacy in high-school students. While engaged in solving the monitoring problem, the high-school students are also trained in species identification – valuable skills since they participate in local field monitoring. On top of this – the image identification data is used to train an artificial intelligence for automated analysis using deep learning. Through this involvement loop, we (1) promote ocean literacy on invasive species and their identifications, (2) foster trust in science, and (3) create tools for future monitoring programs. Here, we present the scientific background to the project, its development and parts, current results and our future hopes for it. We hope this will provide inspiration and dialogue on how to build engaging digital tools for community involvement.

OED2.5 BRIDGING THE GAP: ENHANCING SCIENTIFIC ENGAGEMENT WITH LOCAL STAKEHOLDERS AND COMMUNITIES THROUGH CORPORATE RESPONSIBILITY MODELS

Thursday 6 July 2023

16:30

Jordon K Millward (Imperial College London, United Kingdom)

j.millward22@imperial.ac.uk

This session explores how academic institutions can explore corporate responsibility models and their potential to improve scientific engagement with local stakeholders and communities in biology. This interactive session will explore existing practices across various research institutions and how marketing and corporate techniques can be applied to bridge the gap between scientists and non-scientists, including community outreach initiatives, educational programs, and collaborations with local organizations. This session will explore how stakeholders can engage transparently and inclusivity while providing actionable recommendations for implementing successful corporate responsibility models in the biological sciences. This session explores the potential for corporate responsibility models to foster greater scientific transparency and collaboration between scientists and local communities and offers valuable insights for researchers and practitioners alike.

OED2.6 USING INTERNATIONAL WOMAN'S DAY STEM EVENTS TO PROMOTE STEM CAREERS TO YOUNG PEOPLE

Thursday 6 July 2023 17:00

Victoria Paterson (University of Glasgow)

International Woman’s Day runs annual in early March and is a day to celebrate the achievements of woman and raise awareness of discrimination along with taking action on equity. The University of Glasgow Life Science degrees in association with their Athena Swan awards have held an annual outreach event since 2018, for local Brownie groups. These events are designed to highlight STEM degrees to young people, particularly young woman. We aim to raise aspirations in STEM subjects by engaging them in practical and fun based activities across a range of Life Science degrees and to empower them through confidence building activities. Themes have range from Forensics “CSI” lab-based activities to Zoology field, lab and art activities. Annual we host over 100 Brownies throughout the day split across morning and afternoon sessions, with university staff and student volunteers. This presentation will highlight the range of activities undertaken, the planning involved and most importantly the positive impact from these outreach events.

OED2.7 FROM MULTIDISCIPLINARITY TO SOCIETY: ENGAGING COASTAL COMMUNITIES IN MARINE SCIENCE

Thursday 6 July 2023 17:30

Lénia D. Rato (MARE Polytechnic of Leiria, Portugal), Tiago Simões (MARE Polytechnic of Leiria, Portugal), Inês Morão (MARE Polytechnic of Leiria, Portugal), Sara C. Novais (MARE Polytechnic of Leiria, Portugal), Marco F. L. Lemos (MARE Polytechnic of Leiria, Portugal)

lenia.rato@ipleiria.pt

In early 2023, an Outreach Grant awarded by Society for Experimental Biology was initiated with the goal of disseminate experimental science to non-academic audiences and increase local Public Engagement (PE). Lemos Lab, an R&D group at the Polytechnic of Leiria (Portugal), works mostly within marine experimental biology – a sensitive topic - the overarching theme to raise awareness to society. People often question what researchers and biologists do: in fact, it can be far from the “cliché” of exploring low tide pools and dolphins. Three target audiences were addressed: elementary school children (inspire the new generation of experimental researchers), families (discussing societal problems and solutions being pursued), and senior citizens (foster curiosity and provide a marine science update). Different outreach activities were planned and included macroalgae applications in sustainable agriculture and cosmeceuticals, marine bioinvasions, harmful algal bloom impacts on biodiversity, or pollution in marine animals. One of these activities is to carry out an interactive presentation in elementary schools to understand the role of science in biology and in conservation measures, used to study marine organisms such as the charismatic sea turtles and apex predators as sharks. Other actions partnered with a local Ocean Museum, aiming to engage with families and senior citizens through interactive activities. The activities developed under the frame of this Outreach Grant are transferable to other outreach and PE initiatives in the future - and hopefully had a long-lasting effect in our community, both audience and established partnerships (surrounding elementary schools, museum, and municipalities).

OED2.8 MARINE SCIENCE IN ACTION: LIVE DIALOGUE BETWEEN THE SCIENTISTS AND THE CITIZENS

Thursday 6 July 2023 17:45

Carole Di Poi (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRS-IRD-Ifremer, France), Emilien Pousse (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRS-IRD-Ifremer, France), Elisabeth Le Mouillour (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRSIRD-Ifremer, France), Arnaud Huvet (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRSIRD-Ifremer, France), Ika Paul-Pont (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRSIRD-Ifremer, France), Stéphane Pouvreau (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRS-IRD-Ifremer, France), Yannick Leroy (Oceanopolis, France), Yves-Marie Paulet (Laboratoire de Sciences de l’Environnement de Marin (LEMAR) UMR 6539 UBO-CNRSIRD-Ifremer, France), Céline Liret (Oceanopolis, France) carole.dipoi@ifremer.fr

Oceanolab, a project conceived by the Oceanopolis aquarium and the University of Western Brittany, brings scientists and citizens together around research programmes in marine ecology. The aim is to share science in the making with the public in a common space throughout the duration of a research project. This “win-win” initiative allows the production and dissemination of knowledge, while seeking excellence in both missions. It brings scientists out of their laboratories and closer to the society that questions them. The experiments are conducted on site, from the implementation to the results. Tours and outreach tools inform visitors about the ongoing science and discussion periods take place with the research team.

MicroCO2 sme is the first research project hosted in Oceanolab. It addresses the vulnerability of the flat oyster to microplastic pollution in the context of ocean warming and acidification. Ostrea edulis is of great ecological importance as engineer species, and is the subject of restoration measures in Europe after being listed as a threatened species (OSPAR). We have recreated 12 reefs of oysters and their epibiosis in controlled conditions and exposed them to end-of-century global change scenarios for a year. High-throughput tools will be used for physiological assessment (omics, live-cell imaging) combined with epibiosis monitoring (metabarcoding, functional ecology) in each scenario.

This unique project will inform citizens of the environmental crises facing Humanity and raise awareness of the importance of preventing, halting and reversing the degradation of marine ecosystems. It will also provide robust data for the scientific community and stakeholders.

OED3 - TEACHING INNOVATION AND STUDENT ENGAGEMENT

ORGANISED BY: CLAIRE GARDEN (EDINBURGH NAPIER UNIVERSITY)

SHANE AUSTIN (THE UNIVERSITY OF THE WEST INDIES)

OED3.1 EXPLORING WHAT STUDENT ENGAGEMENT MEANS FOR BIOLOGY EDUCATORS: WHAT CAN GAMIFICATION RESEARCH TELL US?

Tuesday 4 July 2023 13:30

Claire L P Garden (Edinburgh Napier University, United Kingdom)

c.garden@napier.ac.uk

The way we teach experimental biology continues to change as we recover, and learn lessons, from the COVID-19 pandemic. We often discuss student engagement as part of this process, but what does this mean in practice? How can we tell if students are engaged with the learning opportunities we provide? How can we improve student engagement through our teaching and assessment?

Some educators turn to teaching innovations like gamification to help solve issues around student engagement, but there is little empirical evidence on which to build this approach. However, the Gamification for Student Engagement Framework has made it possible to choose game attributes to use in the classroom that should support student engagement. Preliminary evidence will be shared to show that very simple game attributes such as choice or interpersonal interaction, can positively impact student engagement as defined through Kahu’s model. An interactive workshop will explore what student engagement means for us as experimental biology educators. Participants will be invited to share where they see it happening in their classrooms, and how they have used teaching innovation to improve engagement. The aim is to inform and invigorate discussions about student engagement and inspire positive change.

assessment (MacCallum and Casey, 2017). A new final year module (Professional Practice) was developed to provide space and opportunity to support deeper engagement with skills development and help to prepare students for the workplace, assessing student engagement with a Skills Passport type approach. Students were required to reflect on their progress and identify where they were in their learning journey, to be aware of their skills and what gaps remained. Reflective thinking and writing as a way to allow students to stop and assess before moving on into the workplace (Tymon, 2017), also matches with a need for graduates as employees to be able to continue with their own professional development in the future. This case study will describe the approach taken and how this has impacted on students.

MacCallum, J., & Campbell Casey, S. (2017). Enhancing skills development and reflective practice in students during their programme of study. New Directions in the Teaching of Physical Sciences, 12(12),https://doi.org/10.29311/ndtps.v0i12.2368

Tymon, A. (2017). The student perspective on employability. Studies in Higher Education. 38(6), 841-856. DOI:10.1080/030750 79.2011.604408

OED3.3 DESIGN THINKING SUPPORTS HUMAN-CENTRED PROBLEM-SOLVING IN SCIENCE LEARNERS

Tuesday 4 July 2023 14:45

Sarah McLean (Western University, Canada)

sarah.mclean@schulich.uwo.ca

Tuesday 4 July 2023 14:15

Janis MacCallum (Dr Janis MacCallum, United Kingdom)

j.maccallum@napier.ac.uk

Within the School of Applied Sciences, our Skills Passport project has been a longstanding attempt to engage students in reflecting on skills/ attributes and collecting evidence of skills development. However, engagement with the passport has been sporadic and evaluation suggested that students would also like it to be part of programme

Design thinking is a powerful tool that is frequently leveraged in business to support innovative problem-solving. Design thinking is a “human-centred approach to creative problem solving that combines what’s desirable with what’s technologically feasible” (https://www. ideou.com/blogs/inspiration/what-is-design-thinking). In this session, I will argue that teaching science students design thinking skills benefits their scientific critical thinking. Participants will learn about the implementation of design-thinking in a senior undergraduate course about inflammation. Participants will be led through the design thinking process, will learn tips and tricks for implementing design thinking, and learn strategies to support group dynamics and mediate group conflict. Participants will also be provided with practical examples of what this teaching approach "looks-like" in practice and how design thinking sessions are structured. Finally, by the end of this session, participants will be able to ideate how design thinking could be applied in their own practice.

OED3.2

THE USE OF REFLECTIVE BLOG-POSTING TO SUPPORT STUDENT ENGAGEMENT WITH SKILLS DEVELOPMENT AND EMPLOYABILITY.

OED3.4

EXPLORING THE POSSIBILITIES FOR ACTIVE LEARNING WITH LEGO® BRICKS

Tuesday 4 July 2023 15:30

Shane Austin (The University of the West Indies Cave Hill Campus, Barbados), Crystal-Ann Millar (The University of the West Indies Cave Hill Campus, Barbados), Chelsey Austin (The University of the West Indies Cave Hill Campus, Barbados)

shane.austin@cavehill.uwi.edu

In this interactive session, we will engage with several ways that LEGO® bricks have been used to deliver content effectively in the presenter's classes. The work of undergraduate project students who have designed LEGO® brick-based activities will also be presented, and the findings of their work will be discussed with and amongst participants. To conclude, the participants will identify a content area they would like to design a LEGO® activity. The participants will then use simple instructions to design a LEGO® brick activity for their classroom. Some willing participants will be invited to share what they have designed and worked on.

OED3.5 USING VIRTUAL REALITY TO TEACH MICROBIOLOGY ONLINE

Tuesday 4 July 2023 16:15

Claire Donald (University of Glasgow, United Kingdom)

Claire.Donald@Glasgow.ac.uk

Virtual Reality is gaining increasing interest as an educational technology which can be integrated within Higher Education teaching. The University of Glasgow has been working with leading immersive technology company, Edify, to embed tailored VR applications as part of a variety of subject disciplines. Within the life sciences, this is beneficial for delivering complex skills training and overcoming significant pedagogical boundaries encountered in traditional teaching environments, such as associated safety concerns and restrictive equipment costs. A Disease Diagnostic VR app was implemented within Junior Honours Molecular Methods course. Using a combination of lectures, computer tasks and laboratory-based practical sessions, students gain experience of cutting-edge molecular biology techniques, whilst acquiring fundamental knowledge and theory of the life sciences. Student feedback will be presented and discussed

OED3.6 TEACHING INNOVATIONS IN A 3RD YEAR PHYSIOLOGY AND PHARMACOLOGY LABORATORY THAT EMPOWER STUDENTS TO GUIDE THEIR OWN LEARNING

Tuesday 4 July 2023 16:45

Oana Birceanu (Western University, Canada), Angela M Beye (Western University, Canada), Hailey Hunter (Western University, Canada), Baurzhan Negmetzhanov (Western University, Canada), Christina Vanderboor (Western University, Canada), Anita Woods (Western University, Canada)

obircean@uwo.ca

Undergraduate laboratories are an incredible opportunity for students in science to develop skills relevant to the field. However, these environments may appear to be high pressure, due to the many deadlines, introduction to novel skills and concepts, work outside of the laboratory that involves data analysis and processing, and group work. In our large (250+ students) Physiology and Pharmacology 3rd year laboratory, we implemented concepts of Universal Design of Learning (UDL) in managing student workload, testing and deliverables, while also empowering students to design and implement their own experiments using model organisms, cell lines, tissues, and organs relevant to our field in Biomedical Sciences. Building on what we have learned from a virtual setting during the pandemic, we provided varying means of engagement, both virtually and in person, that fostered applied learning and self regulation. Our students were given the opportunity to develop and implement four experiments throughout the academic year, running in parallel with concepts learned in their Physiology and Pharmacology 3rd year seminar courses. With the support from graduate student teaching assistants, technical staff, and faculty members in the department, we implemented a variety of assessments (reports, conference style poster presentations and seminars, take home tests and quizzes) to evaluate student knowledge. In this seminar, I will discuss a variety of teaching innovations that we have implemented in the course, from experimental design and assessments that support student learning, to mentorship provided to graduate teaching assistants on teaching approaches in a university setting.

POSTER SESSION

Wednesday 5 July 2023 17:15-19:15

OED3.7 DESIGN, BUILD AND IMPLEMENTATION OF A NOVEL LEARNING RESOURCE, DIGEST (DEVELOPING INDEPENDENT LEARNING, USING A GAMIFICATION TOOL, FOR RESEARCH METHODS)

Wednesday 5 July 2023

POSTER SESSION

Aleksandra Birn-Jeffery (University of Essex, United Kingdom), Izzie Easton (University of Essex, United Kingdom), Nelson Cortes (University of Essex, United Kingdom), Bernard Liew (University of Essex, United Kingdom), Jamie Tallent (University of Essex, United Kingdom), Sally Waterworth (University of Essex, United Kingdom), Carly Wood (University of Essex, United Kingdom), Gavin Sandercock (University of Essex, United Kingdom), Simon Kemp (University of Essex, United Kingdom), James Black (University of Essex, United Kingdom), Becky Scott (University of Essex, United Kingdom)

a.birn-jeffery@essex.ac.uk

Research methods causes “research anxiety” amongst students, as they perceive it is boring, ‘full of maths’, and ‘won’t use it again’. In fact, research methods covers a range of investigative and analytical skills transferrable across many careers (e.g., presentation and data analysis). Furthermore, this anxiety increases as taught research methods modules occur once a year over 3-year degrees, and the skills are applied at disparate times. A time gap exists in teaching research methods and its application. We have built a novel tool, embedded into the University’s virtual learning environment, called DIGEST, which addresses the challenges of 1) student anxiety of research methods, 2) the time gap of taught content and application, and 3) the perception that research methods is boring. This novel tool is a learning resource, using gamification, to help teach, consolidate, and build confidence in research methods (e.g., aims to ANOVAs). DIGEST consists of a “learning zone”, for knowledge gain, and a “competition zone” to gain confidence and consolidate understanding, whilst embedding “fun” competition to achieve high scores. To assess the impact on confidence and knowledge in students an online survey before and after a month long access to DIGEST was performed. The post survey included student satisfaction questions. To understand engagement with the tool we utilised the virtual learning environments already embedded toolkit. DIGEST will improve inclusivity as it is freely accessible to students online and has dedicated pathways for each degree. DIGEST promotes active learning and builds confidence on topics students view as difficult.

OED4 - GETTING STARTED ON EDUCATIONAL RESEARCH, GETTING PUBLISHED AND OUTPUT

ORGANISED BY: OANA BIRCEANU (WESTERN UNIVERSITY IN LONDON), SUSANNE VOELKEL (UNIVERSITY OF LIVERPOOL)

OED4.1 THE PROCESS OF EDUCATIONAL RESEARCH AND ITS BENEFITS TO TEACHING PRACTICES

Wednesday 5 July 2023 09:00

Luciane V Mello (University of Liverpool, United Kingdom)

lumello@liv.ac.uk

In our lives as scientists, we approach research with rigor, and we constantly ask questions and self-critically evaluate what we are doing. In one way or another, we are all involved in teaching, from delivering lectures to supervising students. If the goal is to train future scientists, teaching should involve the same rigour of inquiry and evaluation that we apply to our research. Therefore, those who teach should engage with educational research (by doing it or reading about others' work) with the intention of improving educational practice or policy. To support those interested in educational research, this presentation aims to raise awareness of the educational research process, including understanding the context, analysing the teaching activities, defining the researchable teaching question, and briefly mentioning research methods in education. Additionally, it will draw attention to common mistakes made during the process and the challenges in achieving publication. Overall, I invite you to discuss the claim that evidence should support teaching practice, just as evidence supports research practice.

commitments and lack of opportunities to do so. In this presentation, I will focus on how these two elements - time and opportunity - were reconciled by the McCall MacBain Teaching and Leadership Postdoctoral Fellowship at McMaster University. As a member of the first ever cohort of postdoctoral fellows to complete this fellowship at McMaster in 2020, I will address the approaches that were used to introduce postdocs from varied backgrounds (Biology, Chemistry, Kinesiology, Physics) to SoTL research, support them through the process (both financially and with resources) and promote their bench research through this entire process. By the end of the presentation, I will demonstrate how bench and education research are not mutually exclusive and how knowledge of education research can benefit teaching practices.

OED4.3 USING A MIXED METHOD APPROACH TO INVESTIGATE THE IMPACT OF LECTURE CAPTURE ON STUDENT LEARNING BEHAVIOUR

Wednesday 5 July 2023

11:00

Susanne Voelkel (University of Liverpool, United Kingdom)

svoelkel@liverpool.ac.uk

Wednesday 5 July 2023 10:00

Oana Birceanu (Western University, Canada)

obircean@uwo.ca

For those pursuing academia in Biology and related fields, the postdoctoral stage of the academic career is often characterized by intense research and writing journal articles, combined with the process of job applications and interviews. For most, teaching opportunities are rare and competitive, while branching into educational research (or the Science of Teaching and Learning - SoTL) is not an option due to time

Lecture capture (the real time recording of live lectures) is widely used in Higher Education institutions across the world. It is highly popular with students many of whom believe that having access to lecture recordings improves their grades. Although lecture capture has many benefits for staff and students, there may also be drawbacks such as decreased attendance of live classes. In a recent study (Voelkel et al. 2023, FEBS Open Biohttp:// dx.doi.org/10.1002/2211-5463.13548) we investigated how the provision of lecture capture affects biological sciences students’ study behaviour. We used a mixed method approach, including a questionnaire and focus groups resulting in qualitative as well as quantitative data. This presentation will discuss the rationale behind our approach. We will examine the methods used to analyse both types of data and how qualitative and quantitative data were used to complement each other. The results of our study indicate that students spend a lot of time watching lecture recordings which may negatively affect the time spent studying other sources. About a third of the participants reported that they are more likely to skip live classes if lectures are recorded. What is more, those students tended to postpone catching up on missed classes, which may potentially lead to last minute cramming and poor attainment. We argue that lecture capture may not be advantageous for all students, and further considerations are required to address this matter.

OED4.2 BENCH AND EDUCATION RESEARCH ARE NOT MUTUALLY EXCLUSIVE: STARTING EDUCATION RESEARCH DURING THE POSTDOCTORAL STAGE OF YOUR CAREER

OED5 - TRANSVERSAL SKILLS IN EXPERIMENTAL BIOLOGY: EMPLOYABILITY IN INDUSTRY AND PROJECT MANAGEMENT

WORKSHOPS

OED5.1 PERSPECTIVES IN BIOECONOMY EDUCATION AND TRAINING.

Davide Viaggi (University of Bologna, Italy)

davide.viaggi@unibo.it

The focus of the speech will be on evolution and perspectives of Bioeconomy education, drawing on the experience of the project BIOBEC and of the European Bioeconomy University network. Both initiatives will be presented shortly, followed by the following main points: a) evolution of education and training needs in the Bioeconomy; b) emerging curricula and education pathways; c) education methods and organisational solutions. This will be developed bringing examples from the bioeconomy education centres designed in the BIOBEC project and in connection with concepts of Bioeconomy innovation systems.

OED5.2 EMBEDDING TRANSVERSAL SKILLS IN BIOLOGICAL SCIENCES UNIVERSITY CURRICULUM

Sheila Amici-Dargan (University of Bristol, United Kingdom), Lucy Alford (University of Bristol, United Kingdom)

anzsld@bristol.ac.uk

University Biological Sciences curricula typically require students to focus on developing specific topics and techniques, rather than transversal skills, both at undergraduate and postgraduate levels. This talk will showcase some examples of how we are embedding transversal skills throughout our Biological Sciences curriculum at the University of Bristol, and how we are supporting our students to identify and articulate the range of skills they have developed that are valued by employers.

OED5.3 TRANSVERSAL SKILLS IN EXPERIMENTAL BIOLOGY:IDENTIFICATION AND PROFESSIONAL CORRESPONDENCE

Javier Santos-Santos (Circular Bio-based Europe Joint Undertaking, Belgium)

jssantos@usal.es

For many academics, a change in career brings about disorientation and sensations of uncertainty. However, with a positive and constructive mindset, this can be counteracted. As a matter of fact, academics possess a broad array of transversal skills that are applicable to a myriad of professions; from research to industry, to management and policymaking. Starting from the different fields of experimental biology, in the following session we will identity some of these skills and match them to contemporary professional areas and occupations.

ORGANISED BY:JAVIER SANTOS-SANTOS, (TRAGSATEC), SHEILA AMICI-DARGAN (UNIVERSITY OF BRISTOL)