1Division of Plant pathology, Indian Agricultural Research Institute, New Delhi-110012
2Division of Biochemistry, Indian Agricultural Research Institute, New Delhi-110012, India.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
Papaya ring spot virus (PRSV) have single stranded RNA genome and causes severe economic losses both in cucurbits and papaya. The extent to which the genome of PRSV is shaped by recombination provides an understanding of molecular evolution of PRSV and helps in studying features such as host specificity, virulence, geographical distribution and their emergence as new epidemics. PRSV-P-DEL isolate had been completely sequenced and compared with the 12 other isolates reported from the rest of the world for their phylogeny and recombination events. Cistron by cistron sequence comparison and phylogenetic analysis based on polyprotein showed the two distinct groupings of Asian and American isolates, although PRSV-P-DEL clustered along with the American isolates. Recombination sites were found throughout the genomes, except in small 6K1 protein gene, VPg and 3’UTR. Statistically significant proportion of recombination hotspots were found in P1 gene and in the 5’UTR, CI and P3. Correlations between the presence of recombination sites, geographical distribution and phylogenetic relationship provide an opportunity to establish the molecular evolution and geographic route of PRSV.
