PHYLOGENIC ANALYSES OF THE FIRE BLIGHT PATHOGEN AND CLOSELY RELATED BACTERIA AND DEVELOPMENT OF PRIMER SETS OF BASED ON PHYLOGENIC DIFFERENCE

It has been reported that Erwinia amylovora biovar 4 (the pathogen of bacterial shoot blight of pear in Japan), other biovars of E. amylovora and E. pyrifoliae formed two distinct monophyletic groups in the phylogenetic trees based on rpoD gene: group 1 contained E. amylovora biovars 1, 2, and 3; group 2 contained E. amylovora biovar 4 and E. pyrifoliae (Matsuura et al., 2007). We designed PCR primers that could amplify the rpoD gene sequences specific to each group. The group 1 specific primer amplified 375 bp of DNA from all of 71 isolates belonging to group 1 but not from any of the 16 isolates belonging to group 2. The group 2 specific primer amplified 375 bp of DNA from all of 16 isolates belonging to group 2 but not from any of the 69 isolates belonging to group 1, but weak amplification was confirmed from two isolates of group 1. PCR products were not amplified from 278 bacterial isolates from Japanese pear flowers.