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Genetics

Comparison of Isozyme and Virulence Diversity Patterns in the Bean Rust Fungus Uromyces appendiculatus. D. C. Linde, Graduate research assistant, Department of Plant Pathology, Agricultural Research Service, Cereal Rust Laboratory, University of Minnesota, St. Paul 55108, Current address: BHN Research, 16750 Bonita Beach Rd., Bonita Springs, FL 33923; J. V. Groth, and A. P. Roelfs. Professor, Department of Plant Pathology, and research plant pathologist, U.S. Department of Agriculture, respectively, Agricultural Research Service, Cereal Rust Laboratory, University of Minnesota, St. Paul 55108 Phytopathology 80:141-147. Accepted for publication 8 August 1989. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1990.. DOI: 10.1094/Phyto-80-141.

Fifty-five enzyme and protein stains were screened in three horizontal starch gel electrophoresis systems for usefulness as phenotypic markers for Uromyces appendiculatus, the bean rust fungus. Thirteen enzymes, representing 15 phenotypic markers, were found suitable for this purpose. Phenotypic diversity as detected by the 15 isozyme markers and virulence on 18 differential bean lines were compared for 27 geographically diverse isolates. Greater diversity was found for virulences than for isozymes. No relationship between geographic and phenotypic distance was found. Three phenotypic clusters based on virulence and isozyme data were identified by cluster analysis. The data support the hypothesis that U. appendiculatus is not a homogeneous species and also suggest that urediospores may occasionally fertilize pycnia in nature.