Hypersensitive Response in Tomato to Xanthomonas campestris pv. vesicatoria. J. B. Jones, Gulf Coast Research and Education Center, University of Florida, 5007 60th Street East, Bradenton 34203. J. W. Scott, Gulf Coast Research and Education Center, University of Florida, 5007 60th Street East, Bradenton 34203. Plant Dis. 70:337-339. Accepted for publication 1 October 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-337.

A genotype of Lycopersicon esculentum, Hawaii 7998, produced a hypersensitive reaction when leaflets were infiltrated with cells of Xanthomonas campestris pv. vesicatoria (X. c. vesicatoria). Electrolyte leakage increased in Hawaii 7998 12 hr after infiltration with 10⁸ cfu/ ml, whereas no increase was observed in Walter (known susceptible) after 24 hr. When leaflets of Hawaii 7998 were infiltrated with 10⁸, 10⁷, 10⁶, or 10⁵ cfu/ml, electrolyte leakage greatly increased in leaflets 24 hr after infiltration with the first two inoculum levels but only slightly with 10⁶. Two tolerant tomato genotypes (Campbell 28 and Ohio 4013) reacted similarly to Walter in electrolyte leakage. Population levels of X. c. vesicatoria in Hawaii 7998 leaflets were 50–100 times lower than in leaflets of Walter or any of the tolerant genotypes when inoculated with 10⁵ cfu/ ml. Leaflets of the same resistant and susceptible genotypes infiltrated with 10⁸ cfu/ ml of the bacterium did not differ greatly in bacterial populations after infiltration.