Genetic and Hormonal Regulation of Sweet Cherry (Prunus avium L.) Maturity across Altitudinal Gradients

Abstract

Lebanon is recognized as a major producer of sweet cherries (Prunus avium L.) within the Mediterranean region. This non-climacteric fruit is grown at various altitudes, leading to considerable variation in maturity dates among cultivated varieties and altitudes and subsequently influencing harvest timing. The interaction between genotype and environment significantly affects fruit maturity dates and physicochemical attributes. Fruit maturation entails the regulated activity of numerous genes. In this study, we analyzed gene expression in the berries of six sweet cherry varieties (“Skeena”, “Teliani”, “Banni”, “Feraouni”, “Mkahal”, and “Irani”) cultivated at five locations, ranging from 1130 m to 2080 m above sea level, from May to July. This research focused on the genes potentially associated with auxin response factors, Abscisic acid receptors, ethylene receptors, gibberellin, and cytokinin regulations. Additionally, hormone analysis encompassing Benzyl Adenine (BA), Zeatin, Salicylic acid (SA), Gibberellic acid (GA3), and Abscisic acid (ABA) quantification was conducted on the same samples. The results revealed significant differences in gene expression concerning harvest dates, varieties, and locations. Abscisic acid and Salicylic acid exhibited higher concentrations in the tested fruits throughout the season. Benzyl Adenine had the lowest detected content in fruits. Data also revealed dynamic changes in phytohormones, especially ABA content, among varieties. When comparing phytohormones for different harvest dates in the same location, significant differences were observed. This work contributes to a deeper understanding of the role of plant hormones and their gene expression in the maturation of non-climacteric fruits.