Overexpression of heterotrimeric G protein beta subunit gene (OsRGB1) confers both heat and salinity stress tolerance in rice

Constitutive overexpression of the rice heterotrimeric G protein beta subunit gene (RGB1) in the commercial rice cultivar BRRI Dhan 55 resulted in improved tolerance to heat or salinity or their combination. Two independently in pianta transformed plants with the gene confirmed to be integrated at T-2 by Southern hybridization and showing high expression at the T-3 seedling stage showed better physiological performance after 8 days in 120 mM salt stress than the wild type. The plants had significantly lower electrolyte leakage and malondialdehyde production, while showing higher levels of chlorophyll. Significantly higher germination at 48 degrees C or with combined stresses of 42/40 degrees C day/night stress in the presence of 120 mM salt for 2 days was also observed. Stress responsive genes such as OsAPX1, OsSOD, OsHKT1, OsHSP1, OsHSP2 and OsCOR47 showed higher expression in the RGB1 positive plants. These RGB1 transgenic plants can likely provide a strong defense against climate change.