Molecular Differentiation of Erwinia amylovora Strains from Europe and the Mediterranean Region

Fire blight is a necrotic disease, which affects fruit trees like apple and pear and some ornamentals (e.g. Cotoneaster and Crataegus spp.) (6). Most European countries and the Eastern Mediterranean area are affected (7). The spreading of the causative bacterium E. amylovora can occur over short distances for example via insects but also over longer distances via birds, wind and asymptomatic plant propagation materials. Recent outbreaks of the disease in Italy (9) and Spain (4) renewed the question about the origin of the pathogen. To describe the epidemic spread of fire blight we have applied two molecular methods: Pulsed Field Gel Electrophoresis (PFGE) (8,9) and determination of short sequence DNA repeats (SSR analysis) (2,3,5).