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Ecology and Epidemiology

Indigenous Plasmids in Xanthomonas campestris pv. citri. E. L. Civerolo, United States Department of Agriculture, Agricultural Research Service, Agricultural Research Center, Beltsville, MD 20705; Phytopathology 75:524-528. Accepted for publication 15 November 1984. 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, 1985. DOI: 10.1094/Phyto-75-524.

Indigenous plasmid DNA was isolated from Xanthomonas campestris pv. citri by lysis of cells in alkaline-SDS. The plasmids were detected by electrophoresis in horizontal agarose slab gels. At least seven plasmids with apparent molecular masses of approximately 12- 53 megadaltons occurred in six laboratory reference strains and 21 clinical strains of diverse host, geographical, and temporal origin. Plasmids with the same or similar electrophoretic mobility in the six reference strains were distributed in five unique plasmid profiles that were associated with different forms of citrus bacterial canker disease (CBCD). However, no specific phenotypic function(s) was associated with any of these plasmids of X.c. pv. citri. Plasmid profiles may be useful in epidemiological studies of this pathogen, supplementing other methods of bacterial detection and identification. Furthermore, these plasmids may be useful for evaluating relationships between strains of X.c. pv. citri associated with different forms of CBCD.