UNLABELLED N-Acetylglucosamine (GlcNAc), the main component of chitin and a major constituent of bacterial peptidoglycan, is present only in trace amounts in plants, in contrast to the huge amount of various sugars that compose the polysaccharides of the plant cell wall. Thus, GlcNAc has not previously been considered a substrate exploited by phytopathogenic bacteria during plant infection. Xan...

The leaf reaction of the Phaseolus vulgaris L. germplasm—UNECA (M6 mutant derived from the cultivar Chimbolito, Costa Rica), ‘Chimbolito’, BAC-6 (Brazil), XAN159 (Centro Internacional de Agricultura Tropical, Cali, Colombia), and ‘PC-50’ (Domican Republic)—to Xanthomonas campestris pv. phaseoli strain V4S1 (Dominican Republic) were determined in two replicated trials conducted in a greenhouse i...

Xanthomonas campestris pv. campestris is the etiological agent of black rot of crucifers, a disease of major economic importance which is a threat to the production of cruciferous crops in many areas of the world [1], During a recent investigation of this patho­ gen for the production of phytotoxic metabolites in liquid culture we observed the biotransformation of certain amino acid constituent...

Filamentous bacteriophages have very strict host specificities. Experiments were performed to investigate whether the A protein of the filamentous phage Cf, which infects Xanthomonas campestris pv. citri but not X. campestris pv. oryzae, is involved in determining Cf's host specificity. The gene encoding the A protein of Cf was cloned and expressed in X. campestris pv. citri. The genomic DNA of...

Many bacterial pathogens employ the type III secretion system (T3SS) to translocate effector proteins into eukaryotic cells to overcome host defenses. To date, most of our knowledge about the T3SS molecular architecture comes from the studies on animal pathogens. In plant pathogens, nine Hrc proteins are believed to be structural components of the T3SS, of which HrcC and HrcJ form the outer and...

The gram-negative bacterium Xanthomonas campestris pv. vesicatoria is the causal agent of spot disease in tomato and pepper. Plants of the tomato line Hawaii 7981 are resistant to race T3 of X. campestris pv. vesicatoria expressing the type III effector protein AvrXv3 and develop a typical hypersensitive response upon bacterial challenge. A combination of suppression subtractive hybridization a...

Xanthomonas campestris pv. campestris possesses a low level of beta-galactosidase and therefore is not able to grow and produce significant amounts of xanthan gum in a medium containing lactose as the sole carbon source. In this study, a beta-galactosidase expression plasmid was constructed by ligating an X. campestris phage phi LO promoter with pKM005, a ColE1 replicon containing Escherichia c...