Maize similar to RCD1 gene induced by salt enhances Arabidopsis thaliana abiotic stress resistance

Plant SRO (SIMILAR TO RCD-ONE) proteins play important roles in regulating oxidation and metal ion metabolism. Numbers of SRO proteins have been functional identified in Arabidopsis and rice, but little is known in maize. In this study, we identified a salt induced SRO gene, ZmSRO1b, from maize and analyzed its characteristics. ZmSRO1b expressed mainly in leaf tissues. The ZmSRO1b is encoded by 595 amino acid residues and shared conserved protein models with AtRCD1 and AtSRO1 from Arabidopsis. Promoter-elements analysis showed ZmSRO1b promoter harbored salt and metal stress responsive elements, DRE, GT-like and MRE. Further promoter inductive analysis by GUS staining and quantification confirmed that ZmSRO1b promoter was induced by salt and cadmium (Cd). Methylviologen (MV) simulated oxidative stress showed ZmSRO1b promoter was also induced by MV. Overexpression of ZmSRO1b in Arabidopsis plants showed increased resistance to salt, Cd and oxidative stress. Our results for the first time experimentally validate the function of ZmSRO1b and contribute to the better understanding of SRO genes across different plant species.