Abstract

Apricot ( Prunus armeniaca L.) fruit are nutritionally abundant with diverse medicinal properties. However, the highly synchronized ripening and short shelf-life of apricot fruits result in concentrated supply and low profitability, constraining the industry’s sustainability. Elucidating molecular mechanism of apricot fruit ripening is essential for modulating fruit ripening progression and facilitating molecular breeding to generate cultivars with diversified ripening times in apricot. Nevertheless, the central regulation pathways remain largely uncharacterized in apricot. In this study, a comprehensive analysis of 1- AMINOCYCLOPROPANE-1-CARBOXYLIC ACID OXIDASE (ACO) gene family, the key enzyme of ethylene biosynthesis, PaACO2 was conducted during apricot fruit ripening. Combined with overexpression assays in both apricot fruit and tomato ( Solanum lycopersicum ), the fruit-specific PaACO2 was required for promoting ethylene biosynthesis and fruit ripening. In addition, 0.7 mmol L⁻¹ ethephon and 2% 1-MCP were applied to treat apricot fruit, and the phenotypic changes combined with WGCNA (Weighted Gene Co-expression Network Analysis) were used to construct a PaACO2 -centered regulatory network, from which the ABA-responsive factor DC3 PROMOTER BINDING FACTOR 3 ( DPBF3 ) was identified. Yeast one-hybrid (Y1H), dual-luciferase (LUC) and electrophoretic mobility shift assays (EMSA) experiments revealed that expression of PaACO2 can be positively regulated by PaDPBF3 via the ABRE element. In conclusion, this study advances our understanding of synergistic regulatory mechanism of ABA and ethylene in promoting fruit ripening, thereby provides novel strategies for ripening management and enhances the commercial value of forest fruit.