PavWRKY30 mediates light-induced anthocyanin biosynthesis to regulate fruit coloration and quality in sweet cherry (Prunus avium L.)

Fruit coloration, a critical determinant of sweet cherry marketability, is primarily governed by light-induced anthocyanin accumulation, yet the underlying regulatory mechanisms remain incompletely understood. In this study, we conducted a comprehensive genome-wide analysis of the WRKY transcription factor family in sweet cherry (Prunus avium), identifying 54 PavWRKY genes that were phylogenetically classified into three major groups (I, II, and III). Comparative and syntenic analyses revealed that segmental duplication events primarily drove the expansion of this gene family, with strong collinearity observed between sweet cherry and other rosaceous species. Through expression profiling under light and bagging treatments across three developmental stages, we identified PavWRKY30 as a key light-responsive candidate specifically induced by light exposure. Transient overexpression of PavWRKY30 in bagged (light-deprived) cherry fruits significantly promoted anthocyanin and flavonoid accumulation, accompanied by upregulated expression of multiple anthocyanin biosynthetic genes including PavF3'H, PavDFR, PavANS, and PavUFGT, as well as the light signaling component PavHY5. Mechanistically, yeast one-hybrid, dual-luciferase reporter, and electrophoretic mobility shift assays demonstrated that PavWRKY30 directly binds to the W-box cis-element in the PavF3'H promoter and activates its transcription. Our findings establish PavWRKY30 as a pivotal light-responsive transcriptional activator that orchestrates anthocyanin biosynthesis through direct regulation of PavF3'H and reveal a novel PavWRKY30-PavF3'H regulatory module. This work provides new insights into the transcriptional control of light-induced fruit pigmentation and identifies a promising genetic target for improving fruit quality in sweet cherry breeding programs.