Characterization of a new potyvirus isolated from peanut (Arachis hypogaea)

During a survey of viruses of peanuts in South Africa a mechanically transmissible virus was isolated from a plant exhibiting chlorotic ringspots and blotches on the leaves. Typical potyvirus-like flexuous particles were detected by electron microscope examination. Pinwheel-shaped and laminated inclusions in ultrathin sections, reaction with a monoclonal antibody directed to a potyvirus common epitope, a single 33 kDa coat protein and aphid transmission using Myzus persicae all confirmed that the virus was a subdivision II member of the Potyviridae. Host range studies suggested that the virus was none of the previously reported potyviruses of peanuts or of subdivision II potyviruses. The serological relationships of the virus were studied using a range of 17 antisera to potyviruses in ELISA and immunosorbent electron microscopy (ISEM). The isolate reacted weakly with antisera to plum pox virus and bean yellow mosaic virus in ISEM only. Nucleotide sequence of a 624 bp DNA product was obtained following immuno-capture with a potyvirus common epitope antiserum, cDNA synthesis and PCR amplification with potyvirus specific primers which amplify the 3' untranslated region and a part of the coat protein gene. The sequence was only distantly related to a number of potyviruses, whether amino acid or nucleotide sequences were used for comparisons. It is proposed that the virus be named peanut chlorotic blotch virus and be accepted as a new member of the genus Potyvirus in the family Potyviridae.