The Softening of Persimmon Fruit Was Inhibited by Gibberellin via DkDELLA1/2

Texture is an important quality index reflecting a series of sensory evaluations of fruit, and softening is the main texture change of most postharvest fruit. Persimmon fruit (Diospyros kaki) shows a pattern of decreasing firmness after harvest, leading to a short duration of sale and excessive waste. We found that the treatment with gibberellin (GA) could effectively inhibit the postharvest softening of persimmon fruit, but the underlying mechanism is unclear. In the GA signal transduction pathway, DELLA protein is the key component and is involved in many growth and development processes regulated by GA, while whether DELLA is involved in GA-regulated fruit ripening is not yet known. In this research, two DELLA genes DkDELLA1/2 were found to enhance the transactivation effect of DkNAC9 on the DkEGase1 promoter, thus participating in persimmon fruit softening regulated by GA. The results may provide new findings for the regulatory network of GA and the DELLA protein family.