Salinity and drought tolerance conferred by in planta transformation of SNAC1 transcription factor into a high-yielding rice variety of Bangladesh

Abiotic stresses such as drought and high salinity unfavorably affect the growth and productivity of crop plants. Therefore, the development of stress-tolerant crops is essential for the affected cultivable areas. It has been shown in the current study that the overexpression of stress-responsive NAC1 (SNAC1) transcription factor (TF) significantly increases salinity and drought tolerance in a farmer-popular high-yielding, transgenic rice. The indica rice variety BRRIdhan 55, which was poorly responsive to tissue culture was transformed with the SNAC1 TF from the rice landrace Pokkali by the in planta method. Addition of acetosyringone in the Agrobacterium suspension and co-culture media increased previously reported transformation efficiencies by four-folds. Integration of foreign genes into the genome of transgenic plants was confirmed by gene-specific PCR and Southern blot analysis. The level of transgene expression (SNAC1) was also quantified by real-time PCR. Genetic segregation ratio for T₁progenies was calculated and found to follow the law of Mendelian inheritance. Phenotypic screening was conducted at T₂and T₃seedling stages where the transgenic lines exhibited much better tolerance compared to their control non-transgenic plants at 120 mM (NaCl) salt as well as drought stress implemented by withholding water for 20 days.