Differential Phenolic Compounds and Hormone Accumulation Patterns between Early- and Mid-Maturing Sweet Cherry (

Color acquisition is one of the most distinctive features of fruit development and ripening processes. The color red is closely related to the accumulation of polyphenolic compounds, mainly anthocyanins, during sweet cherry fruit maturity. In non-climacteric fruit species like sweet cherry, the maturity process is mainly controlled by the phytohormone abscisic acid (ABA), though other hormones may also play a role. However, the coordinated stage-specific production of polyphenolic compounds and their relation with hormone content variations have not been studied in depth in sweet cherry fruits. To further understand the accumulation dynamics of these compounds (hormones and metabolites) during fruit development, two sweet cherry cultivars ("Lapins" and "Glenred") with contrasting maturity timing phenotypes were analyzed using targeted metabolic analysis. The ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) approach revealed that phenolic acids, flavonols, and flavan-3-ols accumulated mainly until the straw-yellow stage in the early-maturing cultivar, while accumulation was mainly at the green stage in the mid-maturing cultivar, suggesting a cultivar-dependent stage-specific production of secondary metabolites. In the mid-maturing cultivar, anthocyanins were detected only from the red stage onward, whereas detection began at the pink stage in the early-maturing cultivar. ABA negatively correlated (