Characterization of betasatellite associated with the yellow mosaic disease of grain legumes in Southern India.

Yellow mosaic disease caused by mungbean yellow mosaic virus (MYMV) belonging to the genus Begomovirus (the family Geminiviridae) is a major constraint in cultivation of grain legumes in India. The urdbean (Vigna mungo (L.) Hepper) and mungbean (Vigna radiata (L.) R. Wilczek) samples affected with yellow mosaic disease exhibits yellow mosaic symptoms along with leaf puckering and leaf distortion in Tamil Nadu. Hence the study was performed to find out if there was any association and influence of betasatellite DNA on the symptom expression of MYMV. Full length viral clones of DNA A and DNA B were obtained through rolling circle amplification from YMD infected samples and identified as mungbean yellow mosaic virus. Interestingly, betasatellite was found to associate with MYMV, and its nucleotide sequence analysis showed its 95% identity with papaya leaf curl betasatellite (DQ118862) from cowpea. The present study represents the first report about the association of papaya leaf curl betasatellite with MYMV and represents a new member of the emerging group of bipartite begomovirus associated with betasatellite DNA.