Pathovars of Pseudomonas syringae causing bacterial brown spot and halo blight in Phaseolus vulgaris L-are distinguishable by ribotyping

Ribotyping was evaluated as a method to differentiate between Pseudomonas s yringae pv. phaseolicola and pv. syringae strains causing bacterial brown s pot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with rest riction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combina tion of data from both procedures yielded 19 combined ribotypes. Cluster an alysis of the combined ribotypes differentiated the pathovars phaseolicola and syringae, as well as different clonal lineages within these pathovars. The potential of ribotyping to screen for correlations between lineages and factors such as geographical region and/or bean varieties is also reported .