Molecular characterization of distinct bipartite begomovirus infecting bhendi (Abelmoschus esculentus L.) in India

Yellow vein mosaic disease of okra is a whitefly transmitted begomovirus causing heavy economic loss in different parts of India. The okra isolate (OY131) of this virus from a bhendi plant [(Abelmoschus esculentus L.) Moench] showing yellow vein mosaic, vein twisting, reduced leaves, and a bushy appearance in the Palem region, New Delhi, India, was characterized in the present study. The complete DNA-A and DNA-B sequences have been determined and are comprised of 2,746 and 2,703 nucleotides, respectively. The betasatellite (DNA-β) component was absent in the sample. The genome organization was typically of biparite begomoviruses, which were characterized earlier. Comparison of DNA-A component with other known begomoviruses suggest that this virus, being only distantly related (<85.9% similarity with its nearest relative, BYVMV) to other known begomoviruses, is a new species. We have tentatively assigned the genome to a novel geminivirus species Bhendi yellow vein mosaic Delhi virus [BYVDV-IN (India: Delhi: okra)]. DNA-B showed highest sequence identity (87.8% identical) to that of a ToLCNDV (AY158080). The phylogenetic analysis of the present isolate is distinct from all other viruses; however clusters with ToLCNDV group infect different crops. The recombination analysis revealed that this isolate has sequences originated from ToLCNDV. This is the first known bhendi yellow vein mosaic disease associated bipartite begomovirus from India.