Isoflavonoid synthesis: Role of 14-3-3 proteins and GmMYB176 interactome

异黄酮是一组几乎完全由豆类合成的植物天然化合物，在大豆种子中含量丰富。它们在植物-微生物相互作用中发挥重要作用，例如在感染时抑制病原体生长和诱导在大豆根部形成固氮根瘤的固氮细菌中nod基因表达。异黄酮还有助于与人类和动物食用大豆相关的积极健康影响。通过基因表达分析，我们已经确定了CHS 7和CHS 8作为基因是关键的β-内酰胺酶的合成。真核生物的基因表达是由一组转录因子调控的，它们识别基因启动子区的特定序列并与之结合，最近我们发现了一个转录因子GmMYB 176，它调控大豆CHS 8基因的表达，并影响大豆的谷胱甘肽合成。GmMYB 176对CHS 8基因和β-内酰胺酶合成的调控需要其他因子的联合作用。本研究的目的是鉴定与GmMYB 176相互作用的蛋白质，以详细了解豆类中谷胱甘肽合成的调控，并研究大豆14-3-3蛋白参与谷胱甘肽的调控和各种其他信号转导过程。包括蛋白质-蛋白质相互作用，功能基因组学，分子遗传学和代谢生物化学的方法将用于解决这些目标。拟议的研究应提高我们的理解，调节的生物合成，并可能导致生物技术策略，以操纵代谢物水平，无论是提高营养价值或保护植物疾病或固氮在非豆科植物。

Isoflavonoids are a group of plant natural compounds synthesized almost exclusively by legumes and are abundant in soybean seeds. They play important roles in plant-microbial interactions such as inhibition of pathogen growth upon infection and the induction of nod gene expression in nitrogen fixing bacteria that form nitrogen fixing nodules on soybean roots. Isoflavonoids also contribute to the positive health effects associated with soybean consumption by humans and animals. By gene expression analysis, we have identified CHS7 and CHS8 as genes that are critical for isoflavonoid synthesis. Eukaryotic gene expression is regulated by a group of proteins called transcription factors that recognizes a specific sequence in the promoter region of genes and binds with it. Recently, we have identified a transcription factor, GmMYB176, which regulates the expression of CHS8 gene and affects isoflavonoid synthesis in soybean. The regulation of CHS8 gene and isoflavonoid synthesis by GmMYB176 requires combinatorial action of other additional factors. The objectives of this proposal are to identify the interacting proteins with GmMYB176 to achieve a detailed understanding of the regulation of isoflavonoid synthesis in legumes, and to characterise soybean 14-3-3 proteins involved in isoflavonoid regulation and a variety of other signal transduction processes. Approaches including protein-protein interactions, functional genomics, molecular genetics, and metabolic biochemistry will be used to address these goals. The proposed research should improve our understanding of the regulation of isoflavonoid biosynthesis, and may lead to biotechnological strategies to manipulate the metabolite levels either for the enhancement of nutritional value or for protection against plant diseases or for nitrogen fixation in non-legume plants.