PLASMID CONTENT OF ISOLATES OF ERWINIA AMYLOVORA FROM ORCHARDS IN WASHINGTON AND OREGON IN THE USA

We examined the plasmid content of a collection of 305 isolates of Erwinia amylovora from Washington and Oregon in the Pacific Northwest of the USA with PCR assays and RFLP. Nearly all isolates of E. amylovora carried plasmid pEA29, which is not found in other species of bacteria, but 4% of the isolates from this region lacked pEA29. The plasmid pEU30, previously reported in pathogenic strains from western states in the USA, was detected in 28% of isolates.
Plasmid preparations from a third of the isolates from an epidemic in Washington in 1988 had altered RFLP patterns, possibly due to the presence of plasmid(s) in addition to pEA29 or pEU30. Considering all samples, the majority of isolates in this region were typical of E. amylovora and harbored only pEA29. Nonetheless, many of the pathogen isolates had altered plasmid content, indicating that plasmid acquisition and propagation in populations of E. amylovora in orchards in the Northwestern USA is more common than previously assumed.

XII International Workshop on Fire Blight

A.B. Carey, P.L. Pusey, T.J. Smith, J.E. Loper, V.O. Stockwell

pear, apple, fire blight, pEA29, pEU30

https://doi.org/10.17660/ActaHortic.2011.896.15