A light-responsive transcription factor SmMYB35 enhances anthocyanin biosynthesis in eggplant (Solanum melongena L.)

Main conclusion SmMYB35, a light-responsive R2R3-MYB transcription factor, positively regulates anthocyanin biosynthesis in eggplant by binding to the promoters of SmCHS , SmF3H , SmDFR , and SmANS and enhancing their activities. In addition, SmMYB35 interacts with SmTT8 and SmTTG1 to form a MBW complex, thereby enhancing anthocyanin biosynthesis. Eggplant is a vegetable rich in anthocyanins. SmMYB35, a light-responsive R2R3-MYB transcription factor, was isolated from eggplant and investigated for its biological functions. The results suggested that the expression of SmMYB35 was regulated by SmHY5 through directly binding to G-box in the promoter region, and the overexpression of SmMYB35 could increase the anthocyanin content in the stems and petals of the transgenic eggplants. SmMYB35 could also bind to the promoters of SmCHS , SmF3H , SmDFR , and SmANS and enhance their activities. In addition, SmMYB35 interacted with SmTT8 and SmTTG1 to form a MBW complex which enhanced anthocyanin biosynthesis. Taking together, we firstly verified that SmMYB35 promoted anthocyanin biosynthesis in plants. The results provide new insights into the regulatory effects of SmMYB35 on key anthocyanin biosynthetic genes and advance our understanding of the molecular mechanism of light-induced anthocyanin synthesis in eggplants.