GmMYB176 Interactome: Identification of Key Factors Involved in Isoflavonoid Biosynthesis in Soybean

MYB transcription factors are one of the largest transcription factor families characterized in plants. An R1MYB transcription factor, GmMYB176 regulates chalcone synthase8 (CHS8) gene expression and isoflavonoid biosynthesis in soybean. We have demonstrated that GmMYB176 alone is not sufficient for CHS8 gene regulation and hypothesized that GmMYB176 acts cooperatively with another factor (s). The current research is designed to elucidate the GmMYB176 interactome for CHS8 gene regulation and isoflavonoid biosynthesis in soybean. GmMYB176 interacting proteins were identified using two translational fusion baits (GmMYB176-YFP and YFP-GmMYB176) by co-immunoprecipitation, followed by liquid chromatography-tandem mass spectrometry. The interaction of selected candidates with GmMYB176 was validated in planta and their DNA binding activities determined. Two key bZIP genes were identified. Their role in isoflavonoid synthesis will be discussed.