Résumé
Xanthomonas campestris pathovar (pv.) vesicatoria (Xcv) is the causal agent of bacterial spot disease of pepper and tomato. The bacteria enter the plant tissue via stomata or wounds. After infection of a plant with Xcv two different types of reactions can be observed dependent on the genotype of both organisms. In the susceptible plant the infection with a virulent Xcv strain gives rise to watersoaked lesions that later on become necrotic (compatible interaction). Is the plant resistant and the bacterium avirulent, a hypersensitive response (HR) is induced (incompatible interaction). The HR is a local defense reaction accompanied by rapid necrosis of the infected tissue, leading to restriction of bacterial growth.