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Molecular Plant Pathology

Linkage of Copper Resistance and Avirulence Loci on a Self-Transmissible Plasmid in Xanthomonas campestris pv. vesicatoria. R. E. Stall, Professor, Department of Plant Pathology, University of Florida, Gainesville 32611; D. C. Loschke(2), and J. B. Jones(3). (2)Assistant professor, Department of Plant Pathology, University of Florida, Gainesville 32611; (3)Assistant professor, Gulf Coast Research and Education Center, University of Florida, Bradenton 34203. Phytopathology 76:240-243. Accepted for publication 16 September 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-240.

Resistance to copper in strains of Xanthomonas campestris pv. vesicatoria was transferred by conjugation to strains sensitive to copper. A self-transmissible plasmid was associated with the transfer of copper resistance. Frequency of conjugation varied with donor and recipient and ranged from 0 to 1.6 x 10-2 transconjugants per donor cell. Strains that were resistant to copper and avirulent on breeding line 10R pepper plants were mated with strains that were sensitive to copper and virulent. Transconjugants, selected for copper resistance only, from these matings were also avirulent. Thus, loci for copper resistance and avirulence to 10R pepper plants are linked and both loci were transferred with the large self-transmissible plasmid. The size of the plasmid with copper resistance (pXvCu) varied, but with several strains it migrated in agarose-gel electrophoresis at nearly the same rate as the wild-type Ti plasmid in Agrobacterium tumefaciens strain 4013 which is approximately 193 kilobases in size.

Additional keywords: bacterial spot of pepper, Capsicum annuum, microbial genetics.