Identification of variants of mungbean yellow mosaic geminivirus by host reaction and nucleic acid spot hybridization

Five naturally occurring variants of mungbean yellow mosaic virus (MYMV), one from Vigna mungo (Bg3D from Delhi), two from Vigna radiata (MbD from Delhi and MbS from Sriganganagar), one from Phaseolus aconitifolia (MoL from Ludhiana) and one from Cajanus cajan (Pp1D from Delhi) were identified by the reaction of different genotypes of V. mungo, P. vulgaris, mung bean (V. radiata), pigeon pea and soyabean (Glycine max). Based on the host reactions a set of differentials was selected, which could beused for differentiating the five variants of MYMV. The variants of MYMV could be further distinguished by nucleic acid spot hybridization (NASH) using full length and fragment probes to MYMV-Bg3D DNA-A and DNA-B. The variants Pp1D and MbD reacted weaklywith all the probes but these isolates could also be differentiated by using a smaller concentration of viral DNA. Based on the degree of hybridization the five variants appeared to fall into two distinct groups i.e. Pp1D in one group and Bg3D, MbS and MoL in the other.