First report of Erwinia amylovora causing fire blight on plum (Prunus domestica) in Hungary.
During July 2011, a severe unusual disease symptom was observed om young shoots on a 10-year old plum tree (Prunus domestica) in the city of Budaörs, near Budapest. The naturally infected shoots showed typical symptoms of fire blight including terminal shoots with brown-to-black necrotic lesions and later, sheperd's crook deformation. The morphological characteristics were determined from the isolates of the infected tissue and it was identified as Erwinia amylovora. A pathogenicity test was conducted and the bacterium was reisolated from lesions on inuculated shoots, fulfilling Koch's postulates. For molecular identification of the pathogen, the 16S rDNA region was amplified from the isolate and a recombinant plasmid was sequenced. The sequence was deposited in GenBank (Accession No. HE610678) and showed 99 to 100% sequence homology with a number of E. amylovora isolates, including type strain AJ233410 with 99% similarity and 100% homology with sequences FN434113 and FN666575. This is thought to be the first report of a natural outbreak of fire blight on plum in Hungary.