Molecular Virology, Mahyco Research Center, Dawalwadi, Jalna, Maharashtra.
Abstracts of Research Papers Presented during the National Symposium of Indian Virological Society at Unit of Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi-110 012, October 14–1.
Cotton leaf curl virus (CLCuV) is highly endemic in Punjab, Haryana and Rajasthan and continued to cause severe damage in cotton. In order to look into the genetic variability among the CLCuV, the isolates showed with symptoms of downward or upward curling, vein thickening and enations were collected from different regions for biological and molecular characterization. In the present study, nearly 700 p fragments constituting common region, complete AV2 gene and partial sequence of AC1 and CP gene were cloned and sequenced. Nucleotide sequence analysis showed that the presence of six different species of geminivirus infecting cotton crop. Majority of the CLCuV isolates belonging to one broad species with eleven strains which shares 88.2–98.1 per cent nucleotide identity. Interestingly the sequences of the CLCuV isolates were identical to okra yellow vein mosaic virus isolates. Three of the cotton leaf curl isolates collected from Punjab belonging to another distinct species which share more than 95 per cent nucleotide identity with the CLCuv-Pak. Remaining four isolates were belonging to independent species which might have ariised due to recombination among the virus isolates. Further an attempt was made to establish the associaiton of DNA beta molecules in CLCuV isolates. Molecular characterization results showed that association of nearly 1.3 kbn full length DNA beta and ∼ 750 bp satellite DNA molecules with the CLCuV isolates collected from three cotton growing regions of North India. The nucleotide sequence analysis revealed that the full length DNA beta molecules were related to two distinct speceis i.e. one group belonging to DNA beta from Rajasthan and other one to Pakistan. It was also observed that the DNA beta from cotton are highly distinct when compare to tomato leaf curl virus and okra yellow vein mosaic virus.
