R2R3-MYB transcription factor GmMYB68 is involved in the accumulation of soybean isoflavones

Abstract

We aimed to investigate the regulatory function of the soybean transcription factor R2R3-MYB (GmMYB68) in isoflavone biosynthesis. Through comprehensive subcellular and chromosomal localization analyses, we found that GmMYB68 was predominantly localized to the nucleus and mapped to chromosome Gm04. Notably, SSR markers near this gene significantly correlated with seed isoflavone content. GmMYB68 overexpression markedly increased isoflavone contents, confirming its positive role in regulating isoflavone synthesis. GmMYB68 also played a crucial role in the response of soybean to abiotic stress. Using RNA-seq and yeast one-hybrid techniques, we discovered an intricate interaction between GmMYB68 and key isoflavone biosynthesis genes GmCHS7 and GmCHS8. These findings provide novel insights into the mechanisms underlying isoflavone biosynthesis. Furthermore, using yeast two-hybrid experiments, we identified proteins interacting with GmMYB68, suggesting roles in the synthesis of physiologically active compounds and abiotic stress response. We not only elucidated the regulatory mechanisms of GmMYB68 in isoflavone biosynthesis and abiotic stress response but also constructed a molecular network encompassing GmMYB68, GmCHS7, and GmCHS8. This network provides a theoretical basis for a better understanding of and strategies for improving soybean isoflavone biosynthesis.