Physical delimitation of the pepper Bs3 resistance gene specifying recognition of the AvrBs3 protein from Xanthomonas campestris pv. vesicatoria.

The pepper (Capsicum annuum) Bs3 gene confers resistance to avrBs3-expressing strains of the bacterial spot pathogen Xanthomonas campestris pv. vesicatoria. To physically delimit Bs3, a pepper YAC library was screened with two flanking DNA markers that are separated from Bs3 by 1.

Gene-for-gene-mediated recognition of nuclear-targeted AvrBs3-like bacterial effector proteins.

Plant disease resistance (R) genes mediate specific recognition of pathogens via perception of cognate avirulence (avr) gene products. The numerous highly similar AvrBs3-like proteins from the bacterial genus Xanthomonas provide together with their corresponding R proteins a unique biological resource to dissect the molecular basis of recognition specificity. A central question in this context is if R proteins that mediate recognition of structurally similar Avr proteins are themselves functionally similar or rather dissimilar.