Sulfide promotes tolerance to drought through protein persulfidation in Arabidopsis.

Hydrogen sulfide (H2S) is a signaling molecule that regulates essential plant processes. In this study, the role of H2S during drought was analyzed, focused on the underlying mechanism. Pretreatments with H2S before imposing drought on plants significantly improved the characteristic stressed phenotypes under drought and decreases the levels of typical biochemical stress markers such as, anthocyanin, proline and hydrogen peroxide. H2S also regulated drought-responsive genes, amino acid metabolism, and repressed drought-induced bulk autophagy and protein ubiquitination, demonstrating the protective effect of H2S pretreatments. Quantitative proteomic analysis identified 887 significantly different persulfidated proteins in plants under control and drought stress. Bioinformatic analyses of the proteins more persulfidated in drought revealed that the most enriched biological processes were cellular response to oxidative stress and hydrogen peroxide catabolism. Protein degradation, abiotic stress responses, and the phenylpropanoid pathway were also highlighted, suggesting the importance of persulfidation to cope with drought-induced stress. Our findings emphasize the role of H2S as a promoter of enhanced tolerance to drought, enabling plants to respond more rapidly and efficiently. Furthermore, the main role of protein persulfidation in alleviating ROS accumulation and balancing redox homeostasis under drought stress is highlighted.