Genotypic characterisation of the Erwinia genus by PCR-RFLP analysis of rpoS gene

Genotypic characterisation of the members of the genus Erwinia, based on the PCR-RFLP analysis of a fragment of the rpoS gene was done. PCR primers deduced from described rpoS gene sequences of E. carotovora allowed the amplification of about 880 bp DNA fragments from all tested Erwinia species. The rpoS fragments, amplified from 20 species of the studied Erwinia genus, were compared by RFLP analysis with 4 enzymes (AluI, Hin6I, HinfI, and Tru1I). Restriction analysis allowed drawing 63 common profiles of RFLP products for all tested Erwinia. From 1 to 3 specific RFLP profiles were identified among most of the species tested. However, in two cases: E. chrysanthemi and E. c. subsp. carotovora 15 and 20 specific RFLP groups were detected, respectively. High variability of genetic profiles of the E. chrysanthemi and E. c. subsp. carotovora can be explained by the wide spectrum of plants, which they infect. The results indicated that rpoS PCR-RFLP analysis is a useful tool for identification of species and subspecies belonging to the former Erwinia genus, as well as for differentiation of strains within E. c. subsp. carotovora and E. chrysanthemi.