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 reaction (PCR). The method involves amplification of a 187 bp DNA fragment, probably of chromosomal origin. All 69 cultures of E. amylovora in an international collection from 10 host species in five countries were successfully identified using the primers. In contrast, discrete PCR products were not amplified from 29 other Erwinia species or from 20 other species of plant pathogenic and saprophytic bacteria. A detectable 187 bp product was consistently amplified from reactions containing as few as 10 colony-forming units in culture and plant tissue. In field trials PCR could detect E. amylovora in apple flowers before fire blight symptoms occurred. This method may have potential in pre-symptomatic disease management.