Identification by PCR analysis on plasmid pEA29 of isolates of Erwinia amylovora responsible for an outbreak in Central Europe.
A collection of 127 strains of E. amylovora, the causal agent of fire blight, was tested by PCR amplification of a fragment of the plasmid pEA29. Variability in the length of the DNA fragment obtained, occurred after digestion by the restriction enzymes MspI and Sau3A. Strains were divided into 3 groups according to the length of the DNA product. Most of the strains analysed were placed into 2 groups. Thirteen strains were clustered into a third group which was linked with the geographical origin of strains: they were all isolates from recently reported outbreaks of fire blight in Austria and in southern Bavaria in Germany. It is suggested that the variation in the length of the amplified fragment was due to an insertion into this fragment.