Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, 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.
Tomato leaf curl disease complex caused by Begomoviruses, is the most severe disease of tomato in India. Samples showing typical tomato leaf curl symptoms i.e. yellowing, upward curling, crumpling, distortion of leaves and stunting of plants were collected from infected fields of Dhanbad region. Viral DNA was isolated and full-length genome ofDNA-A was cloned. A satellite DNA -fÒ was also detected along with DNA-A from infected samples and cloned. Despite of several attempts to amplify a DNA-B component using degenerate primers based on the sequences that are highly conserved for other Begomoviruses and/or with IR sequences, no DNA-B component could be detected. Sequence analysis data revealed that DNA-A (2758 nt) shared 99.5% identity with Tomato leaf curl Gujarat virus - [India:Mirzapur:1999] (ToLCGV-[IN:Mir:99])[AF449999] thus a strain of ToLCGV. Hence, the present isolate is proposed to be named as Tomato leaf curl Gujarat virus ¡V [Dhanbad] (ToLCGV-[Dhn]). DNA-£] (1352 nt) showed 94.8% identity with Tomato leaf curl Beta-[India:NewDelhi:2006] (ToLCfÒ-[IN:ND:06])[EF068245]. Partial tandem repeats of both DNA-A and DNA-£] could infect tomato and Nicotiana benthamiana through agroinoculation. DNA-A alone could induce symptoms on both the hosts tested. However, symptom severity was increased when DNA-A was co-inoculated with DNA- £]. Satellite DNA- £] from Dhanbad could transcomplement DNA-As of Tomato leaf curl New Delhi virus (ToLCNDV) and other strains of ToLCGV. Transcomplementaion among ToLCGV-[Dhn] DNA-A with DNA-Bs of ToLCGV and ToLCNDV is also being studied and will be presented.
