Coat protein sequence comparison of south Indian isolates of Papaya ringspot virus with other Indian subcontinent isolates

Papaya ringspot virus (PRSV) is an economically important pathogen causing the most devastating disease in papaya worldwide. Isolates of PRSV originating from different geographical regions in south India were collected and maintained on natural host papaya. The 3’ terminal region of about 1.7 kb comprising a part of the nuclear inclusion b (NIb) gene, complete coat protein (CP) gene and the 3’ untranslated region (3’UTR) of seven Papaya ringspot virus (PRSV) isolates from south India were cloned and sequenced. The CP nucleotide and deduced amino acid sequences of seven isolates were compared to each other and to sequences of 22 other PRSV isolates from different geographical locations in the Indian subcontinent. The sequence comparisons revealed greater sequence divergence (up to 18.4% and 15% at nucleotide and amino acid levels, respectively) within Indian PRSV populations. All south Indian isolates were clearly separated from isolates of other geographical regions and formed a major group in phylogenetic trees, and the clustering pattern of isolates did not correlate well with their geographical origins