First report of Mungbean yellow mosaic India virus on mothbean in Pakistan

Mungbean yellow mosaic India virus (MYMIV), a bipartite begomovirus, is prevalent on several legume crops in the Indian sub-continent (Pant et al., 2001) and has previously been reported affecting mungbeans in Pakistan (Hussain et al., 2004). Mothbean (Vigna aconitifolia) is grown in only in a few areas of the country, mostly as animal fodder. Recently work on improvement has been initiated due to its potential both for animal and human nutrition.

As a first step, seeds of available mothbean varieties were screened under field conditions. All varieties exhibited a severe yellow mosaic, along with leaf curling on some varieties. Based on symptoms the involvement of MYMIV was suspected. To confirm the identity of the virus, total DNA was extracted from samples of infected plants, resolved in agarose gels and blotted to nylon membranes. A full length MYMIV DNA A clone isolated from mungbean (unpublished results) was used as a probe in Southern hybridisation and detected bands typical of geminiviruses in all samples with symptoms, but not those without; confirming the association of a begomovirus with the disease. To further confirm the identity of the virus, primers specific for the DNA B-encoded nuclear shuttle protein (NSP) gene of MYMIV (Hussain et al., 2004) were used in PCR. These resulted in amplification of an approximately 800bp fragment, that was cloned and sequenced. The complete 771bp sequence of the NSP gene (accession number AM233490) showed 95-92% nucleotide sequence identity (94-92% amino acid similarity) to the NSP gene of other MYMIV isolates. These results confirm the association of MYMIV with yellow mosaic disease of mothbean and is the first report of MYMIV infecting this species in the region. To the best of our knowledge there are no published reports for the presence of MYMIV in this host so far.