Molecular Variability of Yellow Mosaic Virus (YMV) of Blackgram in Southern India

Abstract

Background: The yellow mosaic disease (YMD) creates a major hindrance and known to affect a number of grain leguminous crops in the Indian sub-continent. However, blackgram (Vigna mungo L.) is the most important grain legume crop which is affected widely by this disease. The disease is caused by a single stranded DNA containing begomovirus viz., Yellow mosaic virus (YMV) which is mainly transmitted through whitefly (Bemisia tabaci Genn.). Symptoms include severe patho-physiological alterations characterized by the presence of bright chlorotic yellow patches interspersed with green areas on leaf lamina. The present study was aimed to determine the variability among disease causing agents in six different geographical isolates representing four states viz. Andhra Pradesh, Karnataka, Odisha and Telangana states of southern India during the 2019 rabi season. Methods: The variability of YMV associated with YMD of blackgram was studied based on molecular characterization of partial DNA-A coat protein gene with subsequent nucleotide sequencing and phylogenetic tree construction. Result: The synthetic primers designed for the partial DNA-A segment forms a distinct viral gene specific PCR product. The band size corresponding to CP ~704 bp was obtained for MYMV, whereas CP ~500 bp gene band was obtained for MYMIV. Further, phylogenetic analysis based on partial DNA-A gene sequences of six isolates with other isolates from GenBank formed into two unique clusters viz., MYMV and MYMIV. Overall, our study confirming that the begomovirus causing YMD of blackgram in southern India is explored to be as strains of MYMV and MYMIV.