Grant: Discovery Grants Program - Individual

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.