comparison of p. syringae pv. syringae from different hosts based on pathogenicity and box-pcr in iran

during 2007-2008, 58 strains of p. syringae pv. syringae (pss) were isolated from various prunus species and other hosts such as sugar beet, pear, quince, oat, millet, wheat, barley, and rice in fars, isfahan, kohgiloye and boyer ahmad, chahar mahal-o-bakhtiari provinces of iran. the strains were tested for pathogenicity, the presence of the syrb gene and box pcr (box a1r primer). all tested pss strains were pathogenic on peach seedlings regardless of their original hosts. a total of 58 isolates of the pss and pss ivia 773-1 amplified a 752-bp fragment with the syrb primers. the results of analysis of the box fingerprints from p. syringae pv. syringae strains showed that the strains isolated from stone fruits, graminous hosts and pome fruits formed a relatively distinct cluster, which were separable from the strains isolated from the other hosts. results of this study indicate the existence of a relative degree of host specialization within the heterogeneous pathovar pss.