High-resolution genetic mapping of the pepper resistance locus Bs3 governing recognition of the Xanthomonas campestris pv vesicatora AvrBs3 protein

The pepper (Capsicum annuum) Bs3 gene confers resistance to Xanthomonas cam pestris pv vesicatoria strains expressing the avirulence protein AvrBs3. Us ing amplified fragment length polymorphism (AFLP) and bulked DNA templates from resistant and susceptible plants we identified markers linked to Bs3 a nd defined a 2.1-cM interval containing the target gene. Bs3-linked AFLP fr agments were cloned and conformity of isolated PCR products with the desire d markers was determined by hybridisation to membrane-bound AFLP reactions. AFLP markers flanking the target gene were converted into locus-specific P CR-based markers. These markers were employed for the analysis of 790 plant s segregating for Bs3, resulting in a linkage map with a genetic resolution of 0.13 cM. Mapping of Bs3-linked markers in tomato placed them to a synte nic interval on tomato chromosome 2.