Hydrogen sulfide reduces cell death through regulating autophagy during submergence in Arabidopsis.

KEY MESSAGE: Hydrogen sulfide positively regulates autophagy and the expression of hypoxia response-related genes under submergence to enhance the submergence tolerance of Arabidopsis. Flooding seriously endangers agricultural production, and it is quite necessary to explore the mechanism of plant response to submergence for improving crop yield. Both hydrogen sulfide (H2S) and autophagy are involved in the plant response to submergence. However, the mechanisms by which H2S and autophagy interact and influence submergence tolerance have not been thoroughly elucidated. Here, we reported that exogenous H2S pretreatment increased the level of endogenous H2S and alleviated plant cell death under submergence. And transgenic lines decreased in the level of endogenous H2S, L-cysteine desulfurase 1 (des1) mutant and 35S::GFP-O-acetyl-L-serine(thiol)lyase A1 (OASA1)/des1-#56/#61, were sensitive to submergence, along with the lower transcript levels of hypoxia response genes, LOB DOMAIN 41 (LBD41) and HYPOXIA RESPONSIVE UNKNOWN PROTEIN 43 (HUP43). Submergence induced the formation of autophagosomes, and the autophagy-related (ATG) mutants (atg4a/4b, atg5, atg7) displayed sensitive phenotypes to submergence. Simultaneously, H2S pretreatment repressed the autophagosome producing under normal conditions, but enhanced this process under submergence by regulating the expression of ATG genes. Moreover, the mutation of DES1 aggravated the sensitivity of des1/atg5 to submergence by reducing the formation of autophagosomes under submergence. Taken together, our results demonstrated that H2S alleviated cell death through regulating autophagy and the expression of hypoxia response genes during submergence in Arabidopsis.