Abscisic Acid Stimulates Ethylene Biosynthesis by Repressing the Expression of FaMADS1 in Postharvest Strawberry Fruit

Abscisic acid (ABA) and ethylene are both essential regulators of strawberry fruit (Fragaria × ananassa Duch.) ripening. This study investigated the interplay between ABA and ethylene, revealing that ABA downregulates FaMADS1, thereby de-repressing ethylene biosynthesis genes. Functional validation via FaMADS1 silencing and over-expression confirmed that FaMADS1 acts as a negative regulator of ethylene biosynthesis key genes (FaSAMS1, FaACS1, and FaACO1). Furthermore, dual-luciferase assays demonstrated FaMADS1’s direct suppression of the promoters of key ethylene biosynthesis genes. Collectively, these results elucidated a novel mechanism wherein ABA and ethylene coordinate ripening via FaMADS1-mediated transcriptional repression. This ABA-FaMADS1-ethylene regulatory cascade provides a theoretical basis for targeted postharvest regulation of strawberry ripening, laying a foundation for developing low-cost, hormone-based preservation technologies and molecular breeding strategies to alleviate rapid quality deterioration and economic losses of harvested strawberry.