Molecular detection and identification of Tomato leaf curl New Delhi virus isolate causing yellow mosaic disease in Bitter gourd (Momordica charantia), a medicinally important plant in India

Abstract

Bitter gourd (Momordica charantia) is extensively cultivated in India, China and South East Asia for vegetable and traditional medicines. A severe yellow mosaic disease on bitter gourd (M. charantia) with a significant disease incidence was observed during the survey of different locations of Eastern U.P., India in the year 2007. The disease consisted of yellow mosaic accompanied with slight curling on leaves. The whitefly (Bemisia tabaci) population was also observed in the vicinity. The characteristic disease symptoms and whitefly population indicated the possibility of begomovirus infection. PCR was carried out using the total DNA isolated from infected leaf samples and a pair of begomovirus specific primers which resulted in the expected size (∼800 bp) amplicon in 3/6 samples indicating presence of begomovirus. For further identification of the begomovirus, the PCR amplicons were cloned and sequenced (GenBank accession no. EU439260). The sequence data analysis revealed highest 98–93% similarities with several isolates of Tomato leaf curl New Delhi virus (ToLCNDV) at both nucleotide and amino acid levels. The phylogenetic analysis also showed closest relationships of the isolate (EU439260) with various variant of ToLCNDV. Based on highest sequence similarities and closest relationships with ToLCNDV the virus isolated from bitter gourd was considered as an isolate of Tomato leaf curl New Delhi virus.