SlAREB1 regulates ethylene biosynthesis and mediates the effect of abscisic acid on postharvest ripening of tomato fruit

Ethylene biosynthesis during postharvest ripening of tomato fruit is stimulated by the phytohormone abscisic acid (ABA). This research utilized mature green cherry tomato fruit to elucidate the molecular mechanism of SlAREB1 regulating ethylene biosynthesis and mediating ABA’s effect on postharvest ripening of tomato fruit. Results indicated that ABA treatment expedited alterations in fruit color, firmness, ethylene release rate, and modulated the expression of SlAREB1 and genes associated with ethylene biosynthesis. Meanwhile, SlAREB1 was proven to participate in the regulatory process of ABA on tomato fruit ripening. The results of yeast one-hybrid and dual luciferase assays demonstrated that SlAREB1 interacted with the promoters of ACS2, ACO1, FUL1, and MADS1, and activated their transcriptions, thereby regulating ethylene biosynthesis and subsequently affecting the ripening process of postharvest tomato fruit. The molecular model illustrates that SlAREB1 is a downstream component of ABA signaling that directly regulates ethylene-related genes, thereby mediating ABA’s effect. These findings provide a theoretical basis for further improving the regulatory network of hormone interactions during tomato fruit ripening.