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

Abstract

The in vitro culture conditions plays a critical role in promoting callus and shoot induction in rice during Agrobacteriummediated 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.