Abstract

Multiple approaches (both protein and RNA mediated) were tested to engineer tungro resistant plants using agrobacterium mediated transformation. Transgenic plants expressing RTSV CP3, RTBV ORF I and II in anti-sense and RTBV ORF IV in sense and in double stranded form were analyzed for their resistance against tungro. A variable amount of resistance was observed for the various strategies used. Low levels of RTBV were observed in transgenic lines with dsRNA-mediated resistance while high susceptibility was observed in lines expressing ORF IV in sense orientation. The transgenic lines expressing ORF I and II indicated that the RNA-mediated resistance is a multigenic trait i.e. two, three or more transgenes were necessary to establish the resistance. The transgenic with RTSV CP3 showed less virus accumulation probably due to the low RTSV level due to the transgene. In addition, the standardization of agrobacterium-mediated transformation protocol for ADT-39 variety was done by optimizing the nutrient and hormone concentrations