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Isozyme Analysis and Aminopeptidase Activities Within the Genus Peronosclerospora. J. A. Micales, Research associate, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, Current address: USDA, Forest Service, Forest Products Laboratory, One Gifford Pinchot Dr., Madison, WI 53705; M. R. Bonde, and G. L. Peterson. Research plant pathologist and biological laboratory technician, respectively, U.S. Department of Agriculture, Agricultural Research Service, Foreign Disease-Weed Science Research Unit, Building 1301, Fort Detrick, Frederick, MD 21701. Phytopathology 78:1396-1402. Accepted for publication 12 May 1988. 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, 1988. DOI: 10.1094/Phyto-78-1396.

Electrophoresis and aminopeptidase assays were used to study the taxonomy within the genus Peronosclerospora. The banding patterns of 26 enzymes were determined by horizontal starch gel electrophoresis, and coefficients of similarity were calculated among isolates of P. sorghi, P. sacchari, and P. philippinensis. Isolates of P. sorghi from Thailand were not closely related to any other isolate in this study. Isolates of P. sacchari and P. philippinensis exhibited identical phenotypes for 22 enzymes and probably represent a single species. P. maydis shared phenotypes with P. sacchari and the Thailand isolates but also displayed unique banding patterns in certain enzyme systems. Electrophoresis readily separated isolates of Peronosclerospora from those of Bremia lactucae and Peronospora tabacina. Aminopeptidase assays could not differentiate isolates of P. sorghi, P. sacchari, and P. philippinensis due to large amounts of intraspecific variation.

Additional keywords: corn diseases, downy mildows, fungal genetics, fungal taxonomy, Oomycetes, sugarcane diseases.