Use of fatty acid profiles and repetitive element polymerase chain reaction (PCR) to assess the genetic diversity of Pseudomonas syringae pv. pisi and Pseudomonas syringae pv. syringae isolated from field peas in Australia

Isolates of Pseudomonas syringae pv. pisi and P. syringae pv. syringae obtained from both plants and seed of field peas (Pisum sativum L.) in south-eastern Australia were compared using both fatty acid analysis and genomic DNA fingerprinting by repetitive element polymerase chain reaction (PCR). Fatty acid profiling was not specific enough to distinguish isolates of P. syringae pv. syringae from isolates of P. syringae pv. pisi and could not distinguish Races 2 and 6 of P. syringae pv. pisi from each other. DNA fingerprinting, however, was able to distinguish the Australian isolates of P. syringae pv. syringae from the isolates of P. syringae pv. pisi and group the isolates of P. syringae pv. pisi on the basis of race. DNA fingerprinting successfully identified the pathovar and race of unidentified and misidentified Australian isolates of P. syringae indicating that this method could be used as a rapid laboratory-based test for race determination of isolates of P. syringae pv. pisi. The genetic diversity within the isolates of P. syringae pv. pisi present within Australia is also discussed.