A novel transcription factor-like gene SbSDR1 acts as a molecular switch and confers salt and osmotic endurance to transgenic tobacco.

A salt- and drought-responsive novel gene SbSDR1 is predominantly localised to the nucleus, up-regulated under abiotic stresses and is involved in the regulation of metabolic processes. SbSDR1 showed DNA-binding activity to genomic DNA, microarray analysis revealed the upregulation of host stress-responsive genes and the results suggest that SbSDR1 acts as a transcription factor. Overexpression of SbSDR1 did not affect the growth and yield of transgenic plants in non-stress conditions. Moreover, the overexpression of SbSDR1 stimulates the growth of plants and enhances their physiological status by modulating the physiology and inhibiting the accumulation of reactive oxygen species under salt and osmotic stress. Transgenic plants that overexpressed SbSDR1 had a higher relative water content, membrane integrity and concentration of proline and total soluble sugars, whereas they showed less electrolyte leakage and lipid peroxidation than wild type plants under stress conditions. In field conditions, SbSDR1 plants recovered from stress-induced injuries and could complete their life cycle. This study suggests that SbSDR1 functions as a molecular switch and contributes to salt and osmotic tolerance at different growth stages. Overall, SbSDR1 is a potential candidate to be used for engineering salt and drought tolerance in crops without adverse effects on growth and yield.