Hydrogen gas prolongs the shelf life of kiwifruit by decreasing ethylene biosynthesis

The application of hydrogen-rich water was recently shown to inhibit senescence process of kiwifruit, but it is unclear if hydrogen gas (H2) exerts a similar function. The present results show that the production of endogenous H2 in kiwifruit decreases during ripening. Fumigation with H2 not only increased endogenous H2 concentrations but delayed the softening and cell wall disassembly in flesh. Ethylene (C2H4) production was also inhibited by H2, which was supported by a decrease in 1-aminocyclopropene-1-carboxylate (ACC) concentration, ACC synthase, and ACC oxidase activities, and the downregulation of the corresponding gene transcripts. Further, ACC-induced C2H4 production and ripening were blocked by H2 and the incidence of natural decay and disease incidence were reduced. Overall, the results suggested that the H2-induced delay of kiwifruit ripening resulted from an inhibitory effect on C2H4 biosynthesis.