VvMYBPA2 Regulated the Accumulation of Flavan-3-ols though Forming a Trimeric Complex in ‘Zaoheibao’ Grape

Flavan-3-ols are monomers of Proanthocyanidins (PAs), which important polyphenolic compounds in grapes. Previous studies had shown that VvMYBPA2 was closely related to grape flavan-3-ol biosynthesis, but its regulatory network is still unclear. Here, we found the contents (+)-catechin and (−)-epicatechin, enzyme activities anthocyanidin reductase (ANR) leucoanthocyanidin (LAR) expression VvANR VvLAR1 were increased overexpression leaves compared control. It proved protein interacted with VvWDR1 VvMYC2 by yeast two-hybrid (Y2H) bimolecular fluorescence complementation (BiFC). The promoters bound using one-hybrid (Y1H) assay. These results suggested could form a trimeric complex jointly regulated genes VvLAR1, thereby affecting ANR LAR ultimately regulating flavan-3-ols.