Since 2005, a disease similar to bacterial canker of stone fruit trees was observed in some areas of Kurdistan province, Iran. A total of 12 bacterial isolates were obtained from infected tissues of apricot and peach trees. According to biochemical, physiological and whole cell protein patterns, isolates were identified as Pseudomonas syringae pv. syringae. Some molecular properties of the isolates were studied. Electrophoretic plasmid analysis revealed that isolates contained 1-3 plasmids with estimated mol. wt of 371.4, 93.1 and 16.5 kb. Mutant strains were produced using plasmid curing methods. These mutant strains were not mucoid on nutrient agar containing 5% sucrose. Compared with wild type strains, mutants were sensitive to ampicillin, and mutant strains were more actively motile than wild type strains. Polymerase chain reaction (PCR) was used to detect virB1 and virD4 genes. The predicted 1453 and 513 bp PCR products were obtained for virD4 and virB1 genes, respectively, when a 93.1 kb plasmid was used as template DNA.
