Isolation and Partial Characterization of Peanut Top Paralysis Virus (PTPV), a Destructive Virus Causing a New Disease in Peanut (Arachis hypogaea L.)

A destructive virus, causing top paralysis to peanut, was discovered in the wild germplasm collection growing in the USDA-ARS greenhouses, Stillwater, Oklahoma, USA. The symptoms observed on the wild plant were restricted to a few leaves as green batches in a light green to yellow background with some leaflets having lost most of the basal part of the laminae leaving the top portion rolling upwards forming a cone. The virus was mechanically transmitted to cultivated peanut ( Arachis hypogaea L,.) where it caused more severe and destructive symptoms including stunting, severe malformation of leaves and partial or complete disappearance of leaflet laminae. This virus differed in symptomology, host range, and/or serological reactivity from allpeanut viruses reported in the literature, particularly those causing leaf malformation and stunting. The virus induced necrotic local lesions on Phaseolus vulgaris L. cv. "Topcrop" and chlorotic local lesions with necrotic centres bordered withvery bright intense red color on Chenopodium amaranticolor. In both passive indirect enzyme-linked immunosorbent assay (PAS-ELISA) and Ouchterlony double immunodiffusion test, the virus did not react with antisera against brome mosaic, bean yellow mosaic, peanut stripe, potato Y, tobacco mosaic, watermelon mosaic 1, watermelon mosaic 2, wheat soilborne mosaic, wheat streak mosaic, and zucchini yellow mosaic viruses.
However, in reciprocal cross reactions the virus seemed to share a common antigenic determinant with a peanut mottle virus isolate from Oklahoma (PMV-OK). The virus had flexuous filamentous particles with a length of 750–850 nm, falling within the range reported for the potyvirus group. The virus was successfully purified and the molecular weight of its protein subunit was found to be 30000 d. A polyclonal antiserum was raised in rabbits against the virus and used for reciprocal serological tests.