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Etiology

A Previously Undescribed Nepovirus Isolated from Potato in Peru. R. A. C. Jones, International Potato Center, Apartado 5969, Lima, Peru; C. E. Fribourg(2), and R. Koenig(3). (2)Departamento de Fitopatologia, Universidad Nacional Agraria, Apartado 456, Lima, Peru; (3)Institut für Viruskrankheiten der Pflanzen, Biologische Bundesanstalt, Messeweg 11, D3000 Braunschweig, West Germany. Phytopathology 73:195-198. Accepted for publication 26 July 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-195.

A previously undescribed virus was isolated from a potato plant in central Peru, showing calicolike leaf symptoms. The host range of the virus included a total of 44 species in seven plant families. The virus infected all potato cultivars, and wild potato species inoculated mechanically, but only Solanum chancayense and S. mochisense were infected systemically. Symptomless systemic infection was established in potato cultivars, however, by graft inoculation. The virus was transmitted readily through seed of Nicotiana debneyi, tobacco, Chenopodium quinoa, and C. amaranticolor. It remained infective in leaf sap at a dilution of 10^-3 (but not 10^-4), when heated at 60 C (but not 65 C), and when stored for 7 (but not 8) days. Sap or purified preparations contained isometric particles ~28 nm in diameter. Purified virus sedimented as three components (top b, middle, and bottom) with sedimentation velocities of 55S, 117S, and 135S, respectively. Occasionally a fourth component (top a) of about 40S was obtained. SDS polyacrylamide electrophoresis yielded a single protein with a molecular weight of 58,000 daltons. The virus was serologically unrelated to 17 nepoviruses, but its properties are typical of this group. We propose that the virus be named potato virus U.