Journal of Pure and Applied MicrobiologyVol. 8 No. 6

Sequence Diversity Analysis of Tobacco Streak Virus Infecting Okra (Abelmoschus esculentus L.) in India

S. Rajamanickam* and G. Karthikeyan

Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore - 641 003, India.

Received on 15 September 2014 and accepted on 26 October 2014

 

ABSTRACT

Tobacco streak virus (TSV) is the most economically important virus infecting okra (Abelmoschus esculentus L.) and the samples collected from the field was detected by RT-PCR using coat protein and movement protein genes specific primers. 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 on cowpea plants cv. C 152 and resulted in the production of circular necrotic lesions and death of plants. The coat protein and movement protein genes were amplified with a size of 929 bp and 1.2 kb respectively including the UTR region as part of RNA3 of TSV. Sequence analysis of the coat protein gene had nucleotide similarity of 98.3 to 99.4 per cent with known strains of TSV. The multiple sequence alignment revealed that the sequence had two unique variations at the position 15 where cytosine was substituted with adenine and it produced unique variation at the position 526 where cytosine was substituted with thiamine. There was no deletion and addition between nucleotide sequences in the group, further confirms the placement of the okra strain of TSV in a single subgroup. The nucleotide sequence of movement protein okra strain had single unique variation at position 438, where thiamine was substituted with cytosine. Phylogenetic analysis of the amino acid confirms that the okra strain of TSV forms single subgroup with other crop of Indian isolates.

Keywords : Coat protein, Movement protein, Tobacco streak virus and Diversity analysis.