Structural and functional insights into PavDREB2A-mediated activation of cell wall degradation in Prunus avium fruits

Sweet cherry (Prunus avium) fruit is highly susceptible to postharvest softening, resulting in significant economic losses. This process is driven by the degradation of cell wall components, yet its transcriptional regulation remains unclear. Here, we explored the differential degradation of fruit cell walls in two sweet cherry cultivars with varying levels of fruit firmness. We identified the APETALA2/Ethylene Response Factor (AP2/ERF) family gene PavDREB2A, which is uniquely expressed during the ripening of the low-firmness cultivar. Phenotypic and transcriptomic analyses confirm its role in reducing cell wall integrity and fruit firmness. Through integrated transcriptomics, DAP-seq, and AlphaFold3 screening, we identified four cell wall-modifying genes (PG2, MAN7, EXP1, EXP4) as potential target genes of PavDREB2A. PavDREB2A directly activates these genes by binding to the DRE cis-element in their promoter regions, as shown by dual-luciferase, yeast one-hybrid, and EMSA assays. AlphaFold3 structural predictions indicate that six arginines in the AP2/ERF domain of PavDREB2A are essential for its binding and transcriptional activity. Our findings establish a PavDREB2A-mediated transcriptional pathway that promotes cell wall disassembly during ripening. This study provides both mechanistic insight into fruit texture control and potential molecular targets for breeding sweet cherry cultivars with enhanced firmness and shelf-life.