A Gene from Xanthomonas campestris pv. vesicatoria that Determines Avirulence in Tomato Is Related to avrBs3. Blanca Canteros. Department of Plant Pathology, University of Florida, Gainesville. Gerald Minsavage(1), Ulla Bonas(2), Daryl Pring(1,3), and Robert Stall(1). (1)Department of Plant Pathology, University of Florida, Gainesville; (2)Institute fur Genbiologische Forschung, Berlin, Germany; (1,3)USDA-ARS.. MPMI 4:628-632. Accepted 29 August 1991. 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 1991.

Strains of Xanthomonas campestris pv. vesicatoria that were avirulent in tomato leaves but virulent in pepper leaves were identified. A cloned gene, avrBsP, from one of the strains, Xv 87-7, converted a virulent strain in tomato to avirulent in tomato. A 1.7-kb subclone containing the avirulence gene cross-hybridized with the avirulence gene, which determines race 1 within the pepper group of strains (avrBs3). However, the two avirulence genes differ in their biological activity. The base sequences of the two avirulence genes were almost identical through the 1.7-kb segment of avrBsP, with significant differences only in some bases in the repeat region.