Indian Journal of Virology

Tobacco streak virus (TSV) is a positive single stranded tripartite RNA genome belonging to the genus Iarvirus. TSV is a devastating pathogen and it is responsible for sever economic losses in groundnut, sunflower and cotton and the host range is also extending to other crops. In the present study coat protein gene from TSV, an Indian isolate was cloned into a binary vector pCAMBIA 2300 along with tobacco mosaic virus translational enhancer at the 5’ end of the gene. The gene was cloned under the control of cauliflower mosaic virus 35 S promoter and nopaline synthase poly A sequence and then transformed tobacco leaf discs by Agrobacterium tumefaciens GV3101. A total of 38 regenerated tobacco lines with kanamycin resistance were obtained in the selection media. Putative transgenic lines were tested and verified for the presence and integration of the TSV CP gene by PCR and southern analyses. Expression of the tsv cp gene was confirmed by RT-PCR, ELISA and western analyses. Seedlings from the self-fertilized transgenic plants were challenged with different concentration of the TSV inoculum and observed for the development of disease symptoms. The seedlings that expressed the CP gene were failed to develop symptoms in 50% of the plants for the entire duration of the experiments. About 25% of the plants that expressed the TSV CP were delayed in symptom development and gives partial resistance as compared to untransformed control plants. Increasing the concentrtion of the TSV inoculum also failed to develop symptoms for the duration of the experiments in about 40% of plants. The results of these experiments indicate that economically important plants such as groundnut, sunflower and cotton can be transformed for TSV resistance