Elucidating the downstream pathways triggered by H2S signaling in Arabidopsis thaliana under drought stress via transcriptome analysis.

Hydrogen sulfide (H₂S) is a crucial signaling molecule in plants. Recent studies have shown that H₂S plays an equally important role as nitric oxide (NO) and hydrogen peroxide (H₂O₂) in plant signaling. Previous studies have demonstrated the involvement of H₂S in regulating drought and other stressful environmental conditions, but the exact downstream molecular mechanisms activated by the H₂S signaling molecule remain unclear. In this study, we conducted a comprehensive genome-wide transcriptomic analysis of both wild type (WT) and double mutant (lcd/des1). Arabidopsis thaliana plants were exposed to 40% polyethylene glycol (PEG) to induce drought stress and 20 µM sodium hydrosulfide (NaHS). The resulting transcriptome data were analyzed for differentially significant genes and their statistical enrichments in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The results indicated significant upregulation of genes related to photosynthesis, carbon fixation, plant secondary metabolite biosynthesis, inositol and phosphatidylinositol signaling pathways, and stress-responsive pathways in mutant plants under drought stress. Mutant plants with impaired H₂S signaling mechanisms displayed greater susceptibility to drought stress compared to wild-type plants. In summary, all findings highlight the pivotal role of H₂S signaling in stimulating other drought-responsive signaling pathways.