Receptor-like kinase ERECTA negatively regulates anthocyanin accumulation in grape

Receptor-like kinase (ERECTA, ER) is essential for mediating growth, development, and stress response signaling pathway in plants. In this study, we investigated the effect of VvER on anthocyanin synthesis as a regulatory factor in transgenic grape callus in response to chilling stress. Results showed that overexpression of VvER reduced the expression of transcription factors VvMYBA1, VvMYB5b, VvMYC2, and VvWDR1, as well as the structural genes VvCHS, VvCHI, VvDFR, VvLDOX, and VvUFGT, and inhibited the anthocyanins synthesis of grape callus at 25℃. VvER reduced proline content and antioxidant enzymes activities of superoxide dismutase (SOD) and peroxidase (POD), and inhibited the expression of anthocyanin synthesis genes to reduce the cold resistance of grape callus. In transgenic Arabidopsis, overexpression of VvER promoted the elongation of Arabidopsis rosettes and sprigs. Under strong light treatment, VvER inhibited the accumulation of anthocyanins in Arabidopsis; Transient expression in strawberry fruit showed that VvER inhibited the synthesis of anthocyanin in strawberry fruit by inhibiting the expression of FaCHI, FaCHS, FaDFR and FaUFGT under low temperature treatment at 10°C, but not under the normal temperature of 25℃. Using Yeast two-hybrid, we found that VvER interacted with transcription factor proteins including VvMYBA1, VvMYB5b and VvWDR1. Furthermore, VvER led to the repression of VvUFGT promoter activity and decreased the anthocyanin biosynthesis genes expression by downregulation MBW complex activity. Totally, VvER could inhibit anthocyanin biosynthesis and involve in the grape plant susceptible to cold stress for grape cultivation in northern China.