Molecular characterization and infectivity analysis of MYMIV mungbean isolate in various genotypes of mungbean and cowpea

Abstract

Mungbean is an important source of dietary protein and it is mainly cultivated across South-east Asia for food and feed purpose. Worldwide, mungbean production is continuously decreasing due to various biotic factors such as Yellow mosaic diseases (YMD) caused by Begomoviruses. The viral diseases of mungbean remains a major constraint for its production. Despite its major economic importance, much attention is required towards the viral diseases of mungbean in India. In our study we conducted a survey to investigate viral diseases of mungbean in Assam, North-Eastern, India. We report complete sequences of mungbean infecting Begomovirus from Assam, Mungbean yellow mosaic India virus DNA-A and DNA-B genomic components. The nucleotide sequence comparison analysis revealed that mungbean isolate MYMIV DNA-A [OK431079] having highest similarity (99%) with earlier reported of MYMIV segment DNA-A [KU950430] and lowest similarity (95%) with soybean isolate of MYMIV [AJ416349] whereas mungbean isolates MYMIV DNA-B [OK431080] showed highest identity (96%) with MYMIV GUM14 segment [KY556680] and lowest identity (90%) with MYMIV MI8 segment [FM202444]. Our survey revealed MYMIV mungbean isolate of Assam is a variant of other previously reported isolates characterized in north and central regions of India. We therefore characterized the MYMIV infection in 3 different genotypes of mungbean towards their sensitivity and as well as its other potential host, cowpea through agroinoculation of dimeric infectious clones and confirmed the pathogenicity of MYMIV. This is the first report of mungbean MYMIV isolate also infecting to cowpea with YMD symptoms in North-East India which is experimentally cross validated through Koch's postulate