VIEW ARTICLE

Ecology and Epidemiology

A Variant of Cowpea Chlorotic Mottle Virus Obtained by Passage Through Beans. C. W. Kuhn, Department of Plant Pathology and Plant Genetics, University of Georgia, Athens, 30602; S. D. Wyatt, Department of Plant Pathology and Plant Genetics, University of Georgia, Athens, 30602, Present address: Department of Plant Pathology, Washington State University, Pullman, 99163. Phytopathology 69:621-624. Accepted for publication 13 December 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-621.

After continued propagation of the type strain (T) of cowpea chlorotic mottle virus (CCMV) in California Blackeye cowpeas for several months, the intensity of the chlorotic symptoms diminished. When Bountiful beans were inoculated with sap extracts from such plants, a new variant of CCMV, designated M, was derived. M caused very mild symptoms on cowpeas rather than the bright chlorosis of strain T. There was a close relationship between T and M in serology, replication, specific infectivity, host range, and several biophysical properties. However, isolate T differed from M in symptoms produced on cowpeas, replication in resistant cowpea lines, ability to compete in cowpeas and beans, and in the nature of RNA species 3. Results of studies of pseudorecombination of the RNAs of isolates T and M suggested that RNA-3 of CCMV has two genes, one controlling systemic symptoms and the other controlling coat protein.