Transcriptomics analysis reveals the regulatory role of PsERF3 in anthocyanin biosynthesis of ‘Taoxingli’ plum fruit in response to MeSA treatment

Mature plum fruit (Prunus salicina cv. Taoxingli) exhibits an attractive red appearance and significant nutritional value due to anthocyanin accumulation. Some ‘Taoxingli’ plums are harvested before reaching full ripeness to prevent fruit cracking caused by hot and rainy weather. At this stage, plum fruit has not reached its optimal quality. In this study, methyl salicylate (MeSA) treatment promoted anthocyanin accumulation in earlier-harvested ‘Taoxingli’ plum fruit during postharvest. Transcriptomic techniques were employed to unravel the regulatory mechanisms. A weighted gene co-expression network analysis (WGCNA) was constructed based on RNA-seq data, and 22 co-expression modules were constructed. In the specific module, seven synthetic genes were identified. Thus, a transcription factor (TF)-target gene regulatory network related to anthocyanin biosynthesis was built. Yeast one-hybrid assays and electrophoretic mobility shift assay (EMSA) indicated that PsERF3 could directly bind to the promoter of PsANS via RAA motif. Transient over-expression of PsERF3 accelerated anthocyanin biosynthesis in apple through inducing structural genes expression. This work offers fresh perspectives on the regulatory mechanisms of anthocyanin accumulation in ‘Taoxingli’ plum fruit.