Triphasic volatile emission dynamics and gene expression in postharvest PGF-lost non-melting peach (Prunus persica) var. RedY

The organoleptic quality of peaches, particularly the aroma and texture, serves as an important driver of consumer preference and repeat purchases. While volatile organic compound dynamics have been extensively investigated in conventional melting-flesh and modern firm-textured peach varieties, the postharvest aroma evolution of other textural cultivars remains insufficiently understood. Here, we used a non-melting peach, 'RedY', as representative experimental material, to profile the temporal dynamics of the volatile profile over twenty-eight days of postharvest storage. We confirmed the deletion of polygalacturonase ( PGF ) at Melting Flesh ( M ) locus and identified a triphasic pattern of volatile emission, characterized by a marked increase in aroma compounds during the second stage (Stage-2). Odor characteristics analyses highlighted three critical volatiles (δ-decalactone, 2,4-undecadienal, and 2-dodecenal) as major contributor to intensive fruity aroma emission of Stage-2. Integrating transcriptomics and metabolic analysis, we discovered a conserved auxin regulatory module comprising PpYUC11 , PpARF5 , and PpIAA29 , whose expression correlated with aroma intensity. Multilayer validation, including endogenous IAA fluctuation tracking, exogenous auxin application assays, and transient overexpression experiments, demonstrated that auxin biosynthesis and signaling pathways likely involved in modulating the key aroma compounds release, with δ-decalactone showing the most pronounced response. Our findings demarcated phase-specific aroma dynamics and complemented our understanding of phytohormonal regulation of aroma in peaches, providing insights and potential targets for postharvest quality improvement and breeding strategies.