Association of Tomato Leaf Curl New Delhi Virus, A Bipartite Begomovirus with Mosaic Disease of Snake Gourd in India

Abstract

Total twenty five snake gourd leaf samples showing severe mosaic symptoms were collected from different farmer’s field in Varanasi, Uttar Pradesh State of India. The partial amplified PCR products (1.2kb fragment) were cloned and sequence characterized. On the basis of the determined sequences and sequence analysis, begomovirus associated with symptoms in majority of samples (20) was found to be a member of a bipartite begomovirus species which is closely related to Tomato leaf curl New Delhi virus (ToLCNDV). Therefore one sample was selected for full-length amplification using RCA method. SDT analysis of complete genome of the begomovirus (SnG-1) showed highest nucleotide (nt) identity of 88.5-96.3% (DNA-A) and 82.793.3% (DNA-B) with Tomato leaf curl New Delhi virus (ToLCNDV) infecting different cucurbits in Indian subcontinent. An analysis for recombinant origin of genomes (DNA-A and DNA-B-like sequence) showed major part of their genome was likely, originated by recombination of previously reported begomoviruses (ToLCNDV, ToLCPaV and SLCCNV) infecting different cucurbits species resulting in evolution of new recombinant virus. This is the first report of ToLCNDV associated Snake gourd India and significance of these findings is discussed.