Molecular Diversity of Begomoviruses and Betasatellites Associated With Yellow Vein Mosaic and Leaf Curl Diseases of Okra From the Eastern Region of India

ABSTRACT

Yellow vein mosaic (BYVMD) and enation leaf curl (OELCD) diseases are the two economically important diseases of okra known to be caused by monopartite begomovirus associated with satellite molecule. In the present study, begomovirus isolates associated with BYVMD and OELCD collected from four different geographical locations in eastern India were successfully transmitted to healthy bhendi plants by whiteflies. The inoculated plants developed symptoms similar to those observed in the field within 18–23 days after inoculation. The begomoviruses and their associated betasatellites were amplified by PCR from the rolling circle amplified products from the total DNA extracted from the whitefly transmitted bhendi leaf samples. The DNA‐A component was amplified using abutting primers specific to okra enation leaf curl virus (OELCuV) from Kawardha isolate showing OELCD and to bhendi yellow vein mosaic virus (BYVMV) from Raipur, Kanker and Kawardha isolates showing BYVMD. The DNA‐A and betasatellites amplified from these samples were cloned and sequenced. Sequence analysis revealed that all samples exhibiting symptoms of both bhendi yellow vein mosaic and okra enation leaf curl disease (OELCD) were infected with okra enation leaf curl virus (OELCuV). The OELCuV isolates were identified as recombinants between bhendi yellow vein mosaic virus (BYVMV) and OELCuV and were associated with three distinct betasatellites: Okra enation leaf curl betasatellite (OELCuB), Bhendi yellow vein betasatellite (BYVB), and Ludwigia leaf distortion betasatellite (LLDB). For the first time, the association of LLDB with BYVMD was identified from the eastern region of India. This suggests that BYVMD and OELCD in eastern India might be caused by recombinant OELCuV associated with diverse betasatellites which cause threat to okra production in this region.