StRAV1 negatively regulates anthocyanin accumulation in potato

Previous studies on anthocyanin synthesis in potato mainly focus on the functions of anthocyanin biosynthetic structural genes and members of the MYB-bHLH-WD40 (MBW) complex. In this study, a RAV transcription factor StRAV1 was cloned. Expression analysis showed that the transcription of StRAV1 in yellow/white potato genotypes was significantly higher than in pigmented types. A transient activation assay showed that StRAV1 could inhibit anthocyanin formation in tobacco leaves by decreasing the expression of genes encoding related enzymes. Overexpression of StRAV1 in potato, led to significantly lower anthocyanin accumulation than in control tubers. The StCHS, StANS and St3’5’H promoters were significantly inhibited by StRAV1. These results suggest that the StRAV1 gene negatively regulates anthocyanin synthesis in potato tubers by directly inhibiting the transcription of StCHS, StANS and StF3’5’H. This is the first report on the regulation of anthocyanin synthesis in potato by a RAV gene, thus contributing to a more detailed understanding of this process.