Pseudomonas syringae pv. maculicola (Psm) is a phytopathogen of a wide range of host plants from the cruciferae family, producing blight. Some strains infect Arabidopsis thaliana, whose genetic characteristics has made it a plant model for analyses of different process, such as resistance to phytopathogens. In this study, we have focused on this bacterium in order to understand how plant-pathogen interactions influence its genome organization. Eight strains of Pseudomonas syringae pv. maculicola were selected and analyzed by RFLP using PacI and PmeI restriction enzymes in order to evaluate the conservation of the number and size of the restriction fragment into the strains. The results show heterogeneity in the structure and composition of the Psm genome. This heterogeneity has not a clearly relationship between the production of coronatine and the presence/absence or copy number of plasmids., The genome dynamics could be related with the pathogenicity island even the genome origin.