VviKFB07 F-box E3 ubiquitin ligase promotes stilbene accumulation by ubiquitinating and degrading VviCHSs protein in grape.

Stilbene and flavonoid are phytochemicals in plants and play an important role in plant disease resistance and human health. The regulation of stilbene and flavonoid synthesis in plants has been extensively studied at the transcriptional level, but translational and post-translational controls of stilbene and flavonoid biosynthesis are still poorly understood. In this study, a grape F-box E3 ubiquitin ligase VviKFB07 associated with the metabolism of stilbene and flavonoid was screened out with transcriptome. Overexpression of VviKFB07 in the Nicotiana tabacum resulted in a decrease in flavonol and anthocyanin content in corolla, and stable overexpression assays of VviKFB07 in grape callus promoted the accumulation of resveratrol. Subsequently, Yeast two-hybrid and bimolecular fluorescence complementation assays identified the physical interaction between VviKFB07 and VviCHSs proteins. In vivo experiments verified that VviKFB07 was involved in the ubiquitination and degradation of VviCHSs protein. Taken together, our findings clarify the role of ubiquitin ligase VviKFB07 in the synthesis of stilbene and flavonoid in grapes.