Indian Journal of Virology

Yellow vein mosaic disease is widely distributed in India and it is one of the major constraints to okra production. The disease is caused by an Okra yellow vein mosaic virus (Family: Geminiviridae, Genus: Begomovirus). The virus contains circular ssDNA with a monopartiate genome transmitted by whitefly Bemisia tabaci Genn. At present, the disease is highly endemic in major okra growing regions of Maharashtra, Gujarat, Tamil Nadu, and West Bengal and causing severe crop losses. The disease is characterized by typical yellow vein symptoms, thickening of veins and veinlets, distortion of leaf blade, bending of petiole and stem and stunting of plants. The field isolates were transmitted on to a susceptible okra genotype using viruliferous whiteflies. Based on the preliminary molecular analysis data, three representatives YVM isolates viz., OYVMV-87-H2 (2739 bp), OYVMV-204H7 (2747 bp) and OYVMV-P7 (2745 bp) from Maharashtra and OYVMVSB1 (2758 bp) from West Bengal were cloned and full length DNA A molecules were sequenced, but the DNA B component of the virus could not be isolated from the virus infected tissue. The comparative sequence analysis between Maharashtra and West Bengal isolates indicated that the nucleotide homology varied from 73.4% to 91.5% with MKU reference sequence. The isolates viz., OYVMV87H2 and OYVMV-204H7 shared high degree of homology with the MKU strain and belong to the same species. Other two isolates viz., OYVMV-P7 and OYVMV-SB-1 are highly distinct which shared 85.0% and 73.4% respectively with MKU isolate. OYVMV-P7 and OYVMV-SB-1 from Maharashtra and West Bengal were considered to be a new species of OYVMV infecting okra. Interestingly, the OYVMV-SB-1 from Maharashtra shared 96.7% homology with the ToLCV-Bang IV from Karnataka, which is recombinant infecting okra. This paper discusses the coding and non-coding sequences of OYVMV isolates.