• Genome-wide identification and analysis of the PIF gene family were performed in sweet cherry. • PavPIF3 responds rapidly to light signals among PIF family members in sweet cherry. • PavPIF3 promotes anthocyanin accumulation by directing targeting and upregulating the expression of PavDFR and PavUFGT . • This study identified a novel regulator of light-induced anthocyanin accumulation in sweet cherry. Anthocyanins are important secondary metabolites that determine fruit coloration and contribute to antioxidant activity. While light signaling modulates their biosynthesis, and Phytochrome-interacting factors (PIFs) play essential roles in this process, a systematic characterization of the PIF gene family and its regulatory mechanism in sweet cherry ( Prunus avium ) remain unclear. Here, we performed bagging shading and light exposure treatments on the bicolored sweet cherry ‘Rainier’ to explore the relationship among PavPIF, light signaling, and anthocyanin biosynthesis. Transcript analysis revealed that PavPIF3 expression was significantly upregulated 2 days after bag removal following continuous shading. Functional assays demonstrated that overexpression of PavPIF3 in ‘Rainier’ fruits and calli significantly promoted anthocyanin accumulation. Furthermore, yeast one-hybrid (Y1H) assay, electrophoretic mobility shift (EMSA) assay and dual-luciferase reporter gene assay confirmed that PavPIF3 directly bind to the promoter regions of PavDFR and PavUFGT and significantly activate their transcription. Collectively, these findings elucidated the molecular mechanism by which PavPIF3 mediates light signaling to regulate anthocyanin biosynthesis in sweet cherry, providing a theoretical basis for deciphering the light regulatory network of fruit color formation in sweet cherry.
Wang et al. (Wed,) studied this question.