Exogenous hydrogen sulfide alleviates salt stress by improving antioxidant defenses and the salt overly sensitive pathway in wheat seedlings

Hydrogen sulfide (H2S) has the ability to strengthen plant stress tolerance; however, the effects of H2S on wheat seedlings under salt stress and the underlying molecular mechanism are still unclear. This study examined the effects of exogenous NaHS as H2S donor on photosynthesis, antioxidant system, and the expression profile of genes related to antioxidant defense responses, the salt overly sensitive (SOS) and mitogen-activated protein kinase (MAPK) pathways in wheat seedlings treated with NaCl stress. H2S application improved photosynthesis, and decreased H2O2 and malondialdehyde (MDA) contents in wheat seedling leaves under NaCl stress. In addition, antioxidant enzyme activity and the content of ascorbic acid and reduced glutathione increased with H2S application. Moreover, H2S pretreatment up-regulated expression levels of genes related to antioxidant system, SOS pathway and MAPK pathway as well as the transcription factor dehydration-responsive element binding gene. Overall, these findings suggest that H2S alleviates salt stress in wheat seedlings not only by strengthening antioxidant defense systems, but by coordinating signal transduction pathways related to the stress response at a transcriptional level.