Kiwifruit (Actinidia deliciosa) contributes >4 million tons to global fruit production annually and ranks among the highest dietary sources of vitamin C and bioactive polyphenols. Its quality is mainly influenced by the coordinated regulation of essential metabolites during fruit ripening. Although several important metabolites associated with fruit color, flavor, and nutrition have been elucidated, the dynamic changes and regulatory networks of ripening-associated metabolites remain largely unexplored. In this study, comprehensive metabolic dynamics of developing fruit of Actinidia deliciosa cv. Xuxiang (‘XX’) were investigated through a widely targeted metabolomic analysis. Three metabolites associated with hormone metabolism showed that differentially accumulated 12-oxo-phytodienoic acid (12-OPDA) and jasmonic acid (JA) were downregulated, while abscisic acid (ABA) was upregulated in XX9 vs. XX21, with a Log₂|fold change| of −1.96, −3.09, and 1.76, respectively. Two hub genes (AdOPR3 and AdCYP707A4) were then screened based on integrative analyses of metabolome and transcriptome data, and showed significantly decreased expression during ‘XX’ fruit ripening, which might be responsible for the reduced content of JA and enhanced level of ABA, respectively. Furthermore, co-expression networks of AdOPR3 and AdCYP707A4 were constructed by WGCNA and the potential transcriptional regulators of these two hub genes were predicted based on a correlation threshold over 0.9. Taken together, these results revealed the opposing accumulation patterns of JA and ABA might contribute to physiological ripening in kiwifruit, via the TF-mediated transcriptional regulation of AdOPR3 and AdCYP707A4. These findings provide insights for hormonal control of fruit ripening.

Harvest maturity critically determines the balance between eating quality (evaluated by soluble solids, sugars, acidity, and firmness) and nutritional bioactive compounds in fleshy fruits, yet the optimal window for ‘Fengtang’ plum—a high-sugar cultivar from Guizhou—remains unclear. This study systematically investigated the dynamic changes in fruit quality traits, flavonoid accumulation, antioxidant activity, and their underlying regulatory mechanisms across three on-tree maturity stages (PG, PB, and PY) using integrated metabolomic and transcriptomic approaches. As ripening progressed, soluble solids, soluble sugars, and reducing sugars increased significantly while firmness and titratable acidity declined, optimizing fresh-eating quality at the PY stage, whereas total flavonoid content and DPPH/ABTS antioxidant activities continuously decreased, peaking at the PG stage. Metabolomic analysis identified 35 differentially accumulated flavonoid-related metabolites, comprising 32 reliably annotated flavonoids and 3 tentatively annotated xanthones (MSI Level 3); the reliably annotated flavonoids, particularly flavan-3-ols and flavonols, exhibited persistent downregulation, whereas only a few, including dihydromyricetin-3-O-glucoside and apigenin-5-O-glucoside, showed PY-specific upregulation. Transcriptomic profiling revealed systemic reprogramming of the R2R3-MYB transcription factor family: the progressive downregulation of positive regulators, coupled with the PY-stage upregulation of repressive MYBs, was associated with the overall decline in flavonoid biosynthesis, while certain branch-specific MYBs positively correlated with the few upregulated flavonoid components, suggesting a possible association with localized activation of specific metabolic branches against a background of global downregulation. Collectively, these findings delineate a trade-off pattern between edible quality improvement and bioactive compound decline during ‘Fengtang’ plum ripening and establish a MYB-mediated regulatory network model, providing a theoretical basis for tailoring harvest timing according to industrial end-use and offering candidate gene resources for molecular breeding aimed at nutritional quality enhancement.