A NAC Transcription Factor from 'Sea Rice 86' Enhances Salt Tolerance by Promoting Hydrogen Sulfide Production in Rice Seedlings.

Soil salinity severely threatens plant growth and crop performance. Hydrogen sulfide (HS), a plant signal molecule, has been implicated in the regulation of plant responses to salinity stress. However, it is unclear how the transcriptional network regulates HS biosynthesis during salt stress response. In this study, we identify a rice NAC (NAM, ATAF and CUC) transcription factor, OsNAC35-like (OsNACL35), from a salt-tolerant cultivar 'Sea Rice 86' (SR86) and further show that it may have improved salt tolerance via enhanced HS production. The expression of was significantly upregulated by high salinity and hydrogen peroxide (HO). The OsNACL35 protein was localized predominantly in the nucleus and was found to have transactivation activity in yeast. The overexpression of () in japonica cultivar Nipponbare ramatically increased resistance to salinity stress, whereas its dominant-negative constructs (SUPERMAN repression domain, SRDX) conferred hypersensitivity to salt stress in the transgenic lines at the vegetative stage. Moreover, the quantitative real-time PCR analysis showed that many stress-associated genes were differentially expressed in the and lines. Interestingly, the ectopic expression of triggered a sharp increase in HS content by upregulating the expression of a HS biosynthetic gene, Os, upon salinity stress. Furthermore, the dual luciferase and yeast one-hybrid assays indicated that OsNACL35 directly upregulated the expression of by binding to the promoter sequence of . Taken together, our observations illustrate that OsNACL35 acts as a positive regulator that links HS production to salt stress tolerance, which may hold promising utility in breeding salt-tolerant rice cultivar.