Mechanisms underlying the effect of sodium 4-chlorophenoxyacetate on flavor quality in 'Meizao' cherry.

Plant growth regulators (PGRs) are extensively applied in cherry cultivation to enhance fruit quality. While sodium 4-chlorophenoxyacetate (4-CPANa) is a registered plant growth regulator for cherries, its specific effects on fruit quality and flavor are poorly understood. Herein, the effects of 4-CPANa on both the flavor enhancement and the undesirable grassy aroma formation in 'Meizao' cherry, as well as the underlying mechanisms, were investigated using integrated metabolomic and transcriptomic analyses. The results indicated that while 4-CPANa improved the taste quality of cherry fruit by increasing the sugar-to-acid ratio and promoting key amino acid accumulation, it concurrently enhanced grassy volatile compounds likely via regulating key genes in the jasmonic acid, ethylene, and α-linolenic acid metabolic pathways, thereby affecting the overall flavor profile. This research provides valuable insights for regulating cherry flavor and promoting the high-quality, sustainable development of the cherry industry.