PsbZIP1 and PsbZIP10 induce anthocyanin synthesis in plums (Prunus salicina cv. Taoxingli) via PsUFGT by methyl salicylate treatment during postharvest

Abstract

‘Taoxingli’ plum is a characteristic fruit in Shengzhou, Zhejiang Province, China. It is favored by consumers for its vibrant color and high nutrition, closely related to anthocyanin synthesis and accumulation. Anthocyanin synthase (ANS) and uridine diphosphate flavonoid 3-O-glucosyltransferase (UFGT) are two key enzymes in the downstream portion of anthocyanin synthetic pathways. 100 μM methyl salicylate (MeSA) enhanced the expression of five PsbZIPs (bZIP1, 2, 3, 4, 10), which was positively correlated with the activities of PsANS and PsUFGT, their encoding gene expression, and anthocyanin content. The gene expression validated by qRT-PCR was correspond to FPKM value obtained from the transcriptome data. Yeast one-hybrid assays and motif mutation demonstrated that PsbZIP1 and PsbZIP10 can directly bind to the PsUFGT promoter via the G-box motif (5′-CACGTG-3′). These results indicated that PsbZIP1 and PsbZIP10 triggered anthocyanin synthesis in ‘Taoxingli’ plum fruit by binding to the G-box of the PsUFGT promoter after MeSA treatment during postharvest.