VIEW ARTICLE

Genetics

Genetic Analyses of Two Large-Lesion Isolates of Cucumber Mosaic Virus. D. K. Lakshman, Former graduate research assistant, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; D. Gonsalves, Associate professor, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Phytopathology 75:758-762. Accepted for publication 12 February 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-758.

Four strains of cucumber mosaic virus (CMV) induced small (≤0.1 cm diameter) necrotic lesions upon inoculation to cowpea, Vigna unguiculata ssp. cylindrica 'Catjang.' In addition, a few large (0.4- 0.6 cm) necrotic lesions appear at the rate of 0.11- 5.26% (0.53% average) of total lesions. It was shown that these large lesion-producing isolates were mutants derived from their parent strains (17). In this work, pseudorecombination analysis showed that RNA 2 carries the genetic determinant for the large-lesion phenotype in two large-lesion isolates derived from CMV-C and CMV-N strains. In addition, RNA 1 of a large-lesion isolate of CMV-N was found to be responsible for induction of necrotic local lesions on cotyledons of Cucurbita pepo cultivar President and the inability to move systemically in Nicotiana tabacum cultivar H-423.