Assessing the functional role of color-related CaMYB gene under cold stress using virus-induced gene silencing in the fruit of pepper (Capsicum annuum L.)

Anthocyanin as secondary metabolites exits wildly in the plant kingdom, and its accumulation is regulated by transcription factors. However, lithe is known about role of CaMYB in fruit color of pepper. In this study, a purple-fruited pepper (Capsicum annuum L.) was selected and observed at 8 different stages (Z1 -1-Z1 - 8) during fruit ripening (18, 23, 30, 35, 40, 45, 50, and 55 days after flowering). The results showed that higher accumulation of anthocyanin content was observed at 3 different stages (Z1 -1- Z1 -3) of fruit ripening and decreased in the following stage during fruit ripening, which primarily reflected in change of fruit color (from purple to yellow, and then to red). Expression of genes, especially CaMYB, in the biosynthetic pathway of anthocyanin was responsible for fruit color at 3 different stages (Z1 -1- Z1 -3) of fruit ripening. Further analysis showed that silencing of CaMYB resulted in poor accumulation of anthocyanin, suggesting the positive role of CaMYB in the metabolism of anthocyanin in pepper fruit. Our study will provide a basic insight for anthocyanin synthesis in fruit color formation.