Genetic characterization by fluorescent AFLP of Pseudomonas savastanoi pv. savastanoi strains isolated from different host species

The genetic diversity of 71 Pseudomonas savastanoi pv. savastanoi strains isolated from different host species and from diverse geographical regions was determined by fluorescent amplified fragment length polymorphism (f-AFLP) analysis. Strains of P. syringae pv. syringae, P. s. pv. phaseolicola, P. s. pv. glycinea, P. s. pv. tagetis and P. amygdali were also included as outgroups. Based on cluster analysis of f-AFLP data, all P. s. pv. savastanoi strains showed a high degree of similarity, grouping in a cluster and forming a taxon clearly separate from outgroup strains. AFLP analyses failed to support placing strains of P. s. pv. savastanoi, P. s. pv. phaseolicola and P. s. pv. glycinea in the same species. Strains of P. s. pv. savastanoi formed subclusters that correlated with the host species. Strains within these subclusters were also related to the geographical region where the strains were isolated. Strains of P. s. pv. savastanoi from olive were divided into two subclusters. Strains from oleander were differentiated from those from ash and were divided into two additional subclusters, distinct from olive strains.