ABA and sucrose co-regulate strawberry fruit ripening and show inhibition of glycolysis.

Abstract

Abscisic acid (ABA) and sucrose play an important role in strawberry fruit ripening, but how ABA and sucrose co-regulate this ripening progress remains unclear. The intention of this study was to examine the effect of ABA and sucrose on strawberry fruit ripening and to evaluate the ABA/sucrose interaction mechanism on the strawberry fruit ripening process. Here, we report that there is an acute synergistic effect between ABA and sucrose in accelerating strawberry fruit ripening. The time frame of fruit development and ripening was shortened after the application of ABA, sucrose, and ABA + sucrose, but most of the major quality parameters in treated-ripe fruit, including fruit weight, total soluble solids, anthocyanin, ascorbic acid, the total phenolic content, lightness (L*), chroma (C*), and hue angle (h°) values were not affected. Meanwhile, the endogenous ABA and sucrose levels, and the expression of ABA and sucrose signaling genes and ripening-related genes, such as NCED1, NCED2, SnRK2.2, SuSy, MYB5, CEL1, and CEL2, was all significantly enhanced by ABA or sucrose treatment alone, but in particular, by the ABA + sucrose treatment. Therefore, improving the ripening regulation efficiency is one synergetic action of ABA/sucrose. Another synergetic action of ABA/sucrose shows that a short inhibition of glycolysis occurs during accelerated strawberry ripening. ABA and sucrose can induce higher accumulation of H2O2, leading to a transient decrease in glycolysis. Conversely, lower endogenous H2O2 levels caused by reduced glutathione (GSH) treatment resulted in a transient increase in glycolysis while delaying strawberry fruit ripening. Collectively, this study demonstrates that the ABA/sucrose interaction affects the ripening regulation efficiency and shows inhibition of glycolysis.