Abstract

Tobacco streak virus (TSV) was detected from infected okra (Abelmoschus esculentus L.) samples collected from the field. They were also serologically positive in direct antigen coating enzyme linked immunosorbant assay (DAC-ELISA). Sap inoculation of the okra strain induced local as well systemic infection with the production of circular necrotic lesions infection on cowpea cv. C 152 plants. TSV was characterized by RT-PCR using replicase gene specific primers with three different fragments. The replicase gene was amplified into three different fragments with a size of 1.11, 1.19 and 1.26 kb including the UTR region as part of RNA1 of TSV. The BLAST analysis of full length replicase gene had nucleotide similarity of 99.5 to 79.0 % and amino acid sequence shared sequence similarities of 99.4 to 86.8 % with known strains of TSV. Phylogenetic analysis of the nucleotide confirms that the okra strain of TSV forms single subgroup with other crop of Indian isolates.

Keywords: Replicase gene, Tobacco streak virus, Sequence analysis.