The grouping of strains of Pseudomonas syringae subsp. savastanoi by DNA restriction fingerprinting.
Strains of P. syringae subsp. savastanoi from olive, oleander (Nerium oleander) and ash (Fraxinus) were compared in pathogenicity tests and by DNA restriction fingerprinting using SDS-PAGE and silver staining. Strains from each host were distinguishable by their pathogenicity on the same host and on the other 2 plant species. A division into the same groups was obtained using the unweighted pair-group method with av. (UPGMA) clustering of the data from genomic fingerprinting, although high overall similarity between the strains also indicated that they formed a single, well characterized taxon. It is proposed that the subspecies savastanoi of P. syringae comprises at least 3 groups of strains that differ in their host range, symptomatology on individual hosts and their genomic profile.