Characterization of four isolates of Indian citrus ringspot virus.
The 1283 nucleotides of the coat protein of four isolates of Indian citrus ringspot virus, ICRSV-DI, ICRSV-Ab, ICRSV-Ah and ICRSV-Pu, were cloned in pGEM-T easy vector and sequenced. Analysis of nucleotide and deduced amino acid sequences showed variation near the N terminus and conservation in the core region. Sequence analysis and the phylogenetic tree of both nucleotide and amino acid sequences showed that isolates ICRSV-Ab and ICRSV-DI shared close relationship with ICRSV-D (an isolate from Delhi sequenced earlier) and formed one cluster, while isolates ICRSV-Ah and ICRSV-Pu formed another cluster, and were considered as different strains of the virus. The information on ICRSV coat protein gene will be useful in developing pathogen mediated resistance.