Transgenic Rice Crop

1 Transgenic Rice Crop Abstract Genetic engineering makes it possible for geneticists to alter plants' and animals' gene expression using transgenic techniques. A gene of desired characteristics is introduced into an organism to exhibit new phenotypic expressions that can be passed down to its offspring. Plant biotechnology uses transgenic mechanisms to improve food plants' nutritional value and improve their resilience to adapt to various growth conditions. The new traits produced by transgenes enhance the value of the plant and lowers its cost of production. Transgenic rice plants have their genetic expressions altered to exhibit unique characteristics, which gives them better capabilities or desired phenotypic traits.

Buy this excellently written paper or order a fresh one from acemyhomework.com

2 Introduction Transgenic mechanisms are used to alter the gene hence changing its expression.

Transgenic plants contain transgenes, which have been extracted from a different organism or plant and introduced into its genome. Such plants are commonly referred to as genetically modified plants. Transgenes alter the plant cell's genome, causing changes in the germ cells that can be passed down during reproduction. Genomic changes during the transgenic process result from blocked host gene function, either through replacement by the transgene or introducing an additional gene.

Genetic modification of rice plants by the use of transgene is done to serve various purposes. Transgenic rice plants can express new phenotypic and genotypic traits that do not typically occur in natural rice plants. These modifications make it possible for rice plants to withstand different growth conditions, have additional nutritional value and even be used to produce extractable substances for clinical and scientific use. As discussed in the subsequent sections, transgenic rice crops are produced by targeting specific genes that need to be altered or by introducing new genes that express the desired characteristics.

Currently, transgenic rice plants are being continuously developed and utilized for research purposes and for improving crop yield quality for human consumption. Like other plants, quality addition has been achieved by growing pest resistant, drought tolerant and more nutritious rice crops. Even though this looks promising, there is an international backlash on the production of genetically modified plants for human consumption. This has slowed down efforts to utilize transgenic rice crops to benefit populations, mainly by increasing their nutritional value and reducing production costs. Other than these areas, transgenic rice plants have also been used to produce antigens and antibodies, applied in vaccine production among other clinical uses.

3 This paper reviews past publications on transgenic rice crops produced for various purposes. It includes targeted genes in the transgenic process and the phenotypic effects produced by the plants after transgenesis. The benefits of transgenic rice crops over natural rice crops will also be included, based on the research articles' findings.

Transgenic Mechanisms in Improving the Nutritive Value of Rice Crops Rice is a common food crop worldwide, consumed daily by more than half of its population.

However, rice does not contain a high nutritional content making it a target to improve nutritional intake. Ogo, Ozawa, Ishimaru, Murayama & Takaiwa (2013) developed transgenic rice seeds with high flavonoids content for human consumption. Flavonoids, which are found in few specific species of plants, have increased health-promoting effects, including anticancer, antiviral, anti-aging, antioxidant, and cholesterol-lowering effects, among other properties.

The transgenesis of flavonoids in rice focuses on enzymes in the flavonoid pathway responsible for synthesizing the different flavonoids. The five enzymes involved include cinnamate 4‐hydroxylase (C4H), 4‐coumarate: coenzyme A ligase (4CL), chalcone isomerase (CHI), chalcone synthase (CHS) and phenylalanine ammonia lyase (PAL). The genes involved in the synthesis of flavonoids include the OsPAL, OsC4H, Os4CL, OsCHS, and OsCHI genes and are utilized during transgenesis. These genes and enzymes vary with the specific type of flavonoid targeted. The site of expression of the flavonoid genes is also an issue during the transgenic process as it does not express in the rice endosperm, which is the most consumed part of the rice crop. For this reason, they have to be fused with promoter and terminator genes that are specific for endosperm expression.

The introduction of flavonoids into the endosperm of transgenic rice is one way the crop's health benefits can be increased using transgenic methods. Ogo et al. (2013) successfully increased the flavonoid content in rice by introducing their biosynthetic genes. Other than

4 flavonoids, the golden rice is the other well-known case whereby the phytoene synthase gene was introduced in rice to create rice species with high vitamin A content to combat vitamin A deficiency in Asian countries. To date, the significant challenge for utilizing transgenic approaches in improving the health benefits of rice and other plants is the anti-GMO movements over the safety of these genetically modified food crops. The golden rice took a long period since its development before it was finally approved for human consumption.

Transgenic Mechanisms in the Production of Functional Human Proteins from Rice Crops Human proteins can be produced using transgenic mechanisms. This is achieved by introducing the human genome protein into the plant genome using recombinant gene techniques. Using plants for such purposes provides a better alternative to production than animal models due to reduced ethical issues, lesser probabilities of transmitting infectious agents, and more control on production.

He et al. (2011) produced functional human serum albumin from transgenic rice crops.

The human serum albumin produced has a wide range of applications in clinical set-ups and in cell culture media to produce vaccines and pharmaceuticals. Ideally, making human serum albumin from transgenic plants provides a better alternative to the traditional use of donated human blood that is susceptible to scarcity of donors and higher risk of transmission of infectious viral agents.

A Gt13a gene is introduced into the rice gene codon for its subsequent transcription to produce the human serum albumin from transgenic plants. An endosperm-specific promoter is used to ensure that the targeted human serum albumin genome (OsrHSA) gene is stored in the protein vacuoles within the endosperm. The OsrHSA gene obtained has a similar amino acid

5 sequence, melting point molecular mass and N- and C terminus as human serum albumin obtained from human plasma. Besides, it has identical structural, immunological, biochemical and functional characteristics as the conventional human serum albumin, making the use of transgenic rice crops a great alternative means for its production.

From these findings, it is evident that functional human serum albumin can be synthesized from transgenic rice crops in large quantities. Its large-scale production from transgenic rice has a notable percentage of >99% protein purity. This property confirms the safety of using human serum albumin from transgenic plants. Another advantage associated with it is the lowered cost of production and more tremendous success of large scale production, making it the perfect choice for cost-effective production to meet the growing demand for human serum albumin.

Furthermore, transgenic rice is the best option for such a project as it is regarded as one of the most favorable plants for molecular farming. The only potential setback is that it is a potential environmental risk due to environmental exposure of transgenes. This can be mediated by planting the crop under isolation and having standard procedures throughout the production process to limit environmental exposures.

Transgenic Mechanisms in Improving Production of Rice Crops Transgenic approaches in plant biotechnology have helped improve crops' resilience to environmental stressors, including water scarcity, pest invasion, unfavorable temperatures and alkalinity levels. Peixoto-Junior et al. (2018) used the R2R3-MYB (ScMYBAS1) gene in developing transgenic rice plants that are tolerant to drought. The ScMYBAS1 gene was obtained from sugarcane with genotypic ability to grow and yield in drought-prone

6 environments. The gene modifies how the rice adapts to both well-watered and drought conditions as different gene transcripts of the same gene produce various genotypic changes.

Transgenic mechanisms are applicable in improving the adaptive ability of a crop to its environment by introducing a gene from a different crop that adapts well to that environment.

Genes that increase the adaptability to other water conditions leads to the creation of plants that can survive in well-watered and drought conditions. The genotypic changes associated with the adaptation include increased relative water content and increased biomass in water tolerance.

Drought tolerance is associated with increased biomass accumulation.

Thus, transgenic rice plants' modification makes it possible for them to be droughttolerant and retain their biomass accumulation. Consequently, this can reduce production costs as it improves the crop's adaptability to different water or drought conditions. Similar plant biotechnology approaches have enabled advanced molecular breeding techniques that have led to the development of drought-resistant plants, continually being targeted, especially for large-scale food and cash crops. Generally, transgenic modifications can be used to improve rice crops' resiliency to environmental stressors, which will consequently lower associated costs and prevent loss through natural calamities associated with extreme weather changes.

Transgenic Rice in the Production of Artificial Recombinant Proteins Recombinant proteins have broad applicability in research, pharmaceuticals, clinical and industrial set-ups. Both plant and animal genes can produce recombinant proteins by genetic recombination. The use of plants for gene expression and subsequent production of recombinant proteins is becoming ideal due to less risk of exposure to infectious pathogens, lowered production cost, and better determination of production scale. Artificial recombinant proteins

7 made from edible plants can significantly reduce production costs because purification is not needed. They can be taken orally as part of food and even stored easily in cases of plant seeds.

Takaiwa, Takagi, Hirose & Wakasa (2007) studied transgenic rice in artificial recombinant proteins within the endosperm tissue. The study brought out one of the significant challenges in using plant genome: the lower accumulation of quantity to allow for sustainable recombinant protein production. It is further influenced by protein stability, the cell's genetic background, cell metabolism, and the promoter's strength. Takaiwa et al. (2007) generated transgenic rice crops with a greater capacity to accumulate recombinant proteins. It was made possible using the endosperm‐specific glutelin GluB‐1 promoter gene, making it possible to produce artificial recombinant 7Crp peptides. Transgenic rice crops containing the promoter gene were associated with increased expression of the 7Crp peptides, with high accumulation in the endosperm. Therefore, the transgenic rice endosperm tissue was ideal for the production of recombinant proteins and can accommodate increased amounts of the recombinant protein products.

In an almost similar study, Wakasa, Yasuda & Takaiwa (2006) were able to obtain an increased accumulation of bioactive peptides in transgenic rice seeds through the expression of introduced multiple genes. Rice has always been the target plant in plant biotechnology as its entire genome has already been sequenced and is accessible. Wakasa, Yasuda & Takaiwa (2006) were able to achieve multiple expressions of genes from transgenic rice by utilizing up to three gene cassettes that have been combined into a single vector. The reconstructed binary vectors enabled them to accommodate three different modified glutelin gene cassettes. The result was the ability to accumulate hypocholesterolaemic peptide lactostatin in high levels within the rice endosperm.

8 Epigenetic mechanisms like methylation can affect the expression of a gene that has been introduced into an organism. Such epigenetic mechanisms can suppress or overexpress the transgene. Consequently, transgenes have to be presented within chromosome regions that enable them to resist gene silencing and therefore be strongly expressed. MultiSite Gateway System's use made it possible to assess to integrate different genes into a single binary vector for introduction into the nuclear genome. This way, multiple DNA fragments can be cloned simultaneously. As a recombinant gene technique, the manipulation of vectors to accommodate multiple genes and their subsequent expression allows for multiple transgene expression, which could produce multiple recombinant proteins from a single transgenic plant. It was possible to create transgenic rice plants that could accommodate multiple bioactive and therapeutic peptides from the technique.

Conclusion Transgenic rice plants can exhibit the transgene's phenotypic and genotypic characteristics, making it possible to alter rice crops' genetic expression by introducing the desired transgene. This approach can be applied in various ways, including improving rice value in nutritional content and influencing production factors for better adaptation to environmental stressors. The expressed transgene can also be isolated, harvested, and purified, making it possible to use rice to produce recombinant proteins and the human serum albumin for commercial, clinical, and pharmaceutical use.

9 References He, Y., Ning, T., Xie, T., Qiu, Q., Zhang, L., Sun, Y., Jiang, D., Fu, K., Yin, F., Zhang, W., Shen, L., Wang, H., Li, J., Lin, Q., Sun, Y., Li, H., Zhu, Y., & Yang, D. (2011). Largescale production of functional human serum albumin from transgenic rice seeds. Proceedings of the National Academy of Sciences, 108(47), 19078–19083. https://doi.org/10.1073/pnas.1109736108 Ogo, Y., Ozawa, K., Ishimaru, T., Murayama, T., & Takaiwa, F. (2013). Transgenic rice seed synthesizing diverse flavonoids at high levels: a new platform for flavonoid production with associated health benefits. Plant Biotechnology Journal, 11(6), 734–746. https://doi.org/10.1111/pbi.12064 Peixoto-Junior, F. R., Mara de Andrade, L., dos Santos Brito, M., Macedo Nobile, P., Palma Boer Martins, A., Domingues Carlin, S., Vasconcelos Ribeiro, R., de Souza Goldman, M. H., Nebó Carlos de Oliveira, J. F., Vargas de Oliveira Figueira, A., & Creste, S. (2018).

Overexpression of ScMYBAS1 alternative splicing transcripts differentially impacts biomass accumulation and drought tolerance in rice transgenic plants. PLOS ONE, 13(12), e0207534. https://doi.org/10.1371/journal.pone.0207534 Takaiwa, F., Takagi, H., Hirose, S., & Wakasa, Y. (2007). Endosperm tissue is good production platform for artificial recombinant proteins in transgenic rice. Plant Biotechnology Journal, 5(1), 84–92. https://doi.org/10.1111/j.1467-7652.2006.00220.x Wakasa, Y., Yasuda, H., & Takaiwa, F. (2006). High accumulation of bioactive peptide in transgenic rice seeds by expression of introduced multiple genes. Plant Biotechnology Journal, 0(0), 060606025943005-??? https://doi.org/10.1111/j.1467-7652.2006.00199.x