TAXONOMIC ANALYSIS OF XANTHOMONAS-CAMPESTRIS PV BEGONIAE AND XANTHOMONAS-CAMPESTRIS PV PELARGONII BY MEANS OF PHYTOPATHOLOGICAL, PHENOTYPIC, PROTEIN ELECTROPHORETIC AND DNA HYBRIDIZATION METHODS

One hundred twenty four strains of Xanthomonas campestris pv. pelargonii and 31 strains of X. campestris pv. begoniae were studied by pathogenicity tests, by their reaction for 19 enzymatic tests in API ZYM, their antibiotic sensitivity (30 tests), by computer assisted comparison of whole-cell sodium dodecyl sulphate-solubilized proteins and by DNA: DNA hybridizations. Virulence symptoms were demonstrated for respectively 94 and 100% of the strains of X. campestris pv. pelargonii and X. campestris pv. begoniae on their host plants Pelargonium and Begonia. In the case of pv. begoniae the degree of infection was strongly dependent on the strain. Both pathovars displayed stable phenotypic features and could be differentiated from each other by three enzymatic and three antibiotic sensitivity tests. Upon visual inspection and also by numerical analysis of protein electrophoregrams, both pathovars consisted each of a distinct protein electrophoretic group, separated from other X. campestris pathovars studied. X. campestris pv. pelargonii formed a tight electrophoretic cluster while X. campestris pv. begoniae was more heterogeneous. DNA : DNA hybridizations showed that both pathovars are genotypically homogeneous clusters, clearly separated from five other X. campestris pathovars investigated. © 1990, Gustav Fischer Verlag, Stuttgart · New York. All rights reserved.