Optimisation of plant tissue culture conditions in a popular semi-dwarf indica rice cultivar ADT 39 for effective Agrobacterium-mediated transformation

The in vitro culture conditions plays a critical role in promoting callus and shoot induction in rice during Agrobacterium-mediated transformation. In this research, an attempt was made to optimize the key factors affecting the efficiency of Agrobacterium-mediated transformation in ADT 39 rice cultivar. Among the different combinations of the NB-Asmedia tried with varying concentrations of casein hydrolysate from 0.25 g l⁻¹ to 1.25 g l⁻¹, the media containing 0.5 g l⁻¹ casein hydrolysate supplemented with 2 mg l⁻¹ 2, 4-Dichlorophenoxyacetic acid (2, 4-D), 1 mg l⁻¹6-Benzylaminopurie (6-BAP) and 1mg l⁻¹ Naphthalene Acetic Acid (NAA) was found to be the best with callus induction frequency of 94.44 per cent. Incubation in NB-As media after infection for 20 min. considerably reduced the Agrobacterium overgrowth after co-cultivation. For shoot induction, regeneration media RNMH30 containing varied concentrations of 6-BAP from 2 mg l⁻¹ to 4 mg l⁻¹ was tried, the media containing 3.0 mg l⁻¹ 6-BAP added with 1 mg l⁻¹ NAA recorded the highest shoot induction frequency of 71.11 per cent. The overall transformation efficiency in ADT 39 with the optimized culture conditions was found to be 7.96 per cent.