Références sur les Plantes

Abstract: Mature pollen is very sensitive to cold stress in chilling-sensitive plants. Plant WRKY DNA-binding transcription factors are key regulators in plant responses to abiotic and biotic stresses. Previous studies have suggested that WRKY34 (At4g26440) gene might be involved in pollen viability, although the mechanism involved is unclear. In this study, it is shown that cold treatment increased WRKY34 expression in the wild type, and promoter-GUS analysis revealed that WRKY34 expression is pollen-specific. Enhanced green fluorescent protein-tagged WRKY34 was localized in the nuclei. Pollen harbouring the wrky34 allele showed higher viability than pollen with the WRKY34 allele after cold treatment. Further functional analysis indicated that the WRKY34 transcription factor was involved in pollen development regulated by the pollen-specific MIKC* class of MADS-domain transcription factors under cold stress, and cold-insensitivity of mature wrky34 pollen might be partly attributable to the enhanced expression of transcriptional activator CBFs in the mutants.

Thus, the WRKY34 transcription factor negatively mediated cold sensitivity of mature Arabidopsis pollen and might be involved in the CBF signal cascade in mature pollen.

URL: http://jxb.oxfordjournals.org/content/61/14/3901.abstract Author Address: 1 Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, PR China 2 The Graduate School of the Chinese Academy of Sciences, Beijing 100049, PR China XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Author: Zouhar J, Munoz A, Rojo E, Year: 2010 Title: * Functional specialization within the Vacuolar Sorting Receptor family: VSR1, VSR3 and VSR4 sort vacuolar storage cargo in seeds and vegetative tissues.

Journal: The Plant Journal - Accepted manuscript online: 28 AUG 2010.

Pages: no Label: Physiol Keywords: sorting receptor storage proteins vacuole seed germination gene family Abstract: Summary Two different gene families have been proposed to act as sorting receptors for vacuolar storage cargo in plants: the vacuolar sorting receptors (VSRs) and the receptor homology-transmembraneRING H2 domain proteins (RMRs). However, functional data on these genes is scarce and the identity of the sorting receptor for storage proteins remains controversial. Through a genetic screen we have identified the mtv2 mutant, which is defective in vacuolar transport of the storage cargo VAC2 in shoot apices. Map-based cloning revealed that mtv2 is a loss of function allele of the VSR4 gene. We show that VSR1, VSR3 and VSR4, but not the remaining VSRs or RMRs, participate in vacuolar sorting of VAC2 in vegetative tissues, and 12S globulins and 2S albumins in seeds, an activity that is essential for seedling germination vigor. Finally, we demonstrate that the functional diversification in the VSR family results from divergent expression patterns and also from distinct sorting activities of the family members.

URL: http://dx.doi.org/10.1111/j.1365-313X.2010.04349.x Author Address: Departamento de GenĂŠtica Molecular de Plantas, Centro Nacional de BiotecnologĂ­a-CSIC, E-28049 Madrid, Spain XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX