Characterization of the Erwinia amylovora population in Israel.
A collection of 205 strains of E. amylovora isolated in Israel over a period of 12 years was established. The strains were isolated from different varieties of pear, apple, loquat and quince grown in Israel. The strains were characterized according to their virulence on several hosts, and on the basis of serological and molecular characters. Pathogenicity tests carried out on flowering branches of pear and apple, pear shoots, and on pear and loquats grown in containers outdoors, revealed no significant differences in the severity of blossom blight or shoot blight among the various strains. ELISA and immunofluorescence assays revealed no serotypic groups among the Israeli strains. Genomic diversity was investigated using RAPD analysis with 24 arbitrary 10-base primers. All the strains examined (45 Israeli and 11 from Egypt, Cyprus and Greece) produced the same RAPD patterns with each of the primers used. Amplification patterns were indistinguishable from those produced by strains isolated from neighbouring countries. It is suggested that the population of E. amylovora in Israel is homogenous.