Detection of Erwinia amylovora in plant material using novel polymerase chain reaction (PCR) primers

A rapid and sensitive method has been developed for the specific detection of Erwinia amylovora (Burr.) Winslow et al, using the polymerase chain reac tion (PCR). The method involves amplification of a 187 bp DNA fragment, pro bably of chromosomal origin. All 69 cultures of E. amylovora in an internat ional collection from 10 host species in five countries were successfully i dentified using the primers. In contrast, discrete PCR products were not am plified from 29 other Erwinia species or from 20 other species of plant pat hogenic and saprophytic bacteria. A detectable 187 bp product was consisten tly amplified from reactions containing as few as 10 colony-forming units i n culture and plant tissue. In field trials PCR could detect E. amylovora i n apple flowers before fire blight symptoms occurred. This method may have potential in pre-symptomatic disease management.