title: Identification of a DNA restriction-modification system in Pectobacterium carotovorum strains isolated from Poland.
abstract: OBJECTIVE
  Polish isolates of pectinolytic bacteria from the species Pectobacterium carotovorum were screened for the presence of a DNA restriction-modification (R-M) system.
  
  
  RESULTS
  Eighty-nine strains of P. carotovorum were isolated from infected potato plants. Sixty-six strains belonged to P. carotovorum ssp. atrosepticum and 23 to P. carotovorum ssp. carotovorum. The presence of restriction enzyme Pca17AI, which is an isoschizomer of EcoRII endonuclease, was observed in all isolates of P. c. atrosepticum but not in P. c. carotovorum. The biochemical properties, PCR amplification, and sequences of the Pca17AI restriction endonuclease and methyltransferase genes were compared with the prototype EcoRII R-M system genes. Only when DNA isolated from cells of P. c. atrosepticum was used as a template, amplification of a 680 bp homologous to the gene coding EcoRII endonuclease.
  
  
  CONCLUSIONS
  Endonuclease Pca17AI, having a relatively low temperature optimum, was identified. PCR amplification revealed that the nucleotide sequence of genes for EcoRII and Pca17AI R-M are different. Dcm methylation was observed in all strains of Pectobacterium and other Erwinia species tested. The sequence of a DNA fragment coding Dcm methylase in P. carotovorum was different from that of Escherichia coli.
  
  
  CONCLUSIONS
  Pca17AI is the first psychrophilic isoschizomer of EcoRII endonuclease. The presence of specific Dcm methylation in chromosomal DNA isolated from P. carotovorum is described for the first time. A 680 bp PCR product, unique for P. c. atrosepticum strains, could serve as a molecular marker for detection of these bacteria in environmental samples.
authors.affiliation: Department of Biotechnology - Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland.
authors.forename: K
authors.initials: K
authors.lastname: Waleron
authors.forename: M
authors.initials: M
authors.lastname: Waleron
authors.forename: J
authors.initials: J
authors.lastname: Osipiuk
authors.forename: A J
authors.initials: AJ
authors.lastname: Podhajska
authors.forename: E
authors.initials: E
authors.lastname: Lojkowska
mesh_terms: D001483:Base Sequence; D015254:DNA Modification Methylases / Q000235:genetics; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics; D005784:Gene Amplification / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D008745:Methylation; D016973:Pectobacterium carotovorum / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D015280:DNA Restriction-Modification Enzymes; D004269:DNA, Bacterial; D015254:DNA Modification Methylases; C046545:CCWGG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific