Molecular characterization of NL 1n strain of BCMV infecting common bean in Himachal Pradesh and development of diagnostic kits

Abstract

newline Common bean (Phaseolus vulgaris L.), locally known as Rajmash one of the most newlinewidely grown grain legume crop grown around the world is vulnerable to the attack of wide range newlineof plant pathogens. Among these bean mosaic disease caused by Bean common mosaic virus newline(BCMV), a member of family Potyviridae is most important to low yield contributing factor newlinebecause of its regular occurrence and ubiquitous seed borne nature. In India, five strains of newlineBCMV viz., NL-1, NL-1n, NL-4, NL-7 and NL-7n have been reported from north-western newlineHimalayas, of which NL-1n is widely prevalent in the entire region. The present investigations on newlineBCMV- NL-1n strain were undertaken to obtain complete genome sequence, relationship with newlinedifferent strains and to elucidate the presence of R-genes to find out durable sources of resistance. newlineTypical symptoms produced were mosaic, blistering, downward leaf rolling, green vein banding, newlinethickening of leaves, reduction of leaf lamina and leaf deformation which were more severe on newlineseed borne infected plants as compared to sap inoculated. DAS-ELISA test and coat protein gene newlineamplification confirmed the identity of virus as BCMV and reaction pattern on International newlinedifferential set of bean varieties established the strain identity. This strain was separated from newlineother BCMV strains on the basis of temperature sensitivity assay as it induced temperature newlineinsensitive necrosis on cv. Jubila that contains resistance gene (I, bc-1), thus differs from all other newlinestrains of BCMV and BCMNV. The genome size was 10.081 kb and contains an open reading newlineframe that encoded a single polyprotein of 3222 amino acids which cleaved into ten proteins newlinetypical of Potyvirus. Sequence homology, multiple alignment and phylogenetic analysis on newlinenucleotide and amino acid sequences showed that BCMV-NL-1n is more closely related to newlineBCMV-NL-1 though clustered along with other strains and isolates of BCMV. HC-Pro region newlinesequences based comparison among BCMV strains showed its potential for the discrimination of newlinedifferent st