Identification of Mungbean yellow mosaic India virus infecting Vigna mungo var. silvestris L.

Abstract

Yellow mosaic of Vigna mungo var.  silvestris, a wild relative of blackgram (Vigna mungo [L.] Hepper), was noticed at the Indian Institute of Pulses Research, Kanpur, India during 2008–2010, with an incidence of 100 per cent. The observed symptoms, consisting of veinal yellowing and scattered bright yellow spots, were suggestive of infection with a begomovirus. To characterize the virus, several sets of primer pairs were designed to amplify the targeted DNA fragments of the causal virus. The sequence data revealed that the coat protein (AV1) gene of the begomovirus under study contained a single open reading frame with 774 nucleotides, coding for 257 amino acids. Comparative analysis of the coat protein (AV1) gene of the virus under study (FJ821189) showed a 97 and 99% similarity with Mungbean yellow mosaic India virus (MYMIV)-Mungbean strain at the nucleotide and the amino acid levels respectively. Sequence homology of different genes (AC1, AC2, AC3 and AC4) of the isolate under study (FJ663015) with MYMIV-Mungbean (EU523045) was 94–97% for the nucleotides and 91–99% for the amino acids sequence. Therefore, the begomovirus infecting V. mungo var. silvestris at Kanpur is to be considered a strain of MYMIV and is designated as MYMIV-VSKN. This appears to be the first report of the molecular characterization of MYMIV infecting V. mungo var. silvestris.