Tol-Pal proteins are critical cell envelope components of Erwinia chrysanthemi affecting cell morphology and virulence

• Published in: Microbiology (Society for General Microbiology) 2005-10, Vol.151 (10), p.3337-3347
• Main Authors: Dubuisson, Jean-Francois, Vianney, Anne, Hugouvieux-Cotte-Pattat, Nicole, Lazzaroni, Jean Claude
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biogenesis of cell structures, supramolecular organization; Biological and medical sciences; Cell Membrane - metabolism; Cichorium intybus - microbiology; Cloning, Molecular; Dickeya chrysanthemi - genetics; Dickeya chrysanthemi - pathogenicity; Dickeya chrysanthemi - physiology; Dickeya chrysanthemi - ultrastructure; Erwinia chrysanthemi; Escherichia coli; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Genetic Complementation Test; Haemophilus ducreyi; Membrane Proteins - genetics; Membrane Proteins - metabolism; Microbiology; Molecular Sequence Data; Movement; Mutation; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Plant Diseases - microbiology; Plant Leaves - microbiology; Plant Roots - microbiology; Salmonella enterica; Sequence Analysis, DNA; Solanum tuberosum; Solanum tuberosum - microbiology; Vibrio cholerae; Virulence
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.28237-0

Unité de Microbiologie et Génétique, UMR 5122 CNRS-INSA-UCBL, Université Claude Bernard Lyon I, bât. André Lwoff, 69622 Villeurbanne Cedex, France Correspondence Jean Claude Lazzaroni lazzaron{at}biomserv.univ-lyon1.fr The tol-pal genes are necessary for maintaining the outer-membrane integrity of Gram-negative bacteria. These genes were first described in Escherichia coli , and more recently in several other species. They are involved in the pathogenesis of E. coli , Haemophilus ducreyi , Vibrio cholerae and Salmonella enterica . The role of the tol-pal genes in bacterial pathogenesis was investigated in the phytopathogenic enterobacterium Erwinia chrysanthemi , assuming that this organism might be a good model for such a study. The whole Er. chrysanthemi tol-pal region was characterized. Tol-Pal proteins, except TolA, showed high identity scores with their E. coli homologues. Er. chrysanthemi mutants were constructed by introducing a uidA –kan cassette in the ybgC , tolQ , tolA , tolB , pal and ybgF genes. All the mutants were hypersensitive to bile salts. Mutations in tolQ , tolA , tolB and pal were deleterious for the bacteria, which required high concentrations of sugars or osmoprotectants for their viability. Consistent with this observation, they were greatly impaired in their cell morphology and division, which was evidenced by observations of cell filaments, spherical forms, membrane blebbing and mislocalized bacterial septa. Moreover, tol-pal mutants showed a reduced virulence in a potato tuber model and on chicory leaves. This could be explained by a combination of impaired phenotypes in the tol-pal mutants, such as reduced growth and motility and a decreased production of pectate lyases, the major virulence factor of Er. chrysanthemi . Abbreviations: CCCP, carbonyl cyanide m -chlorophenylhydrazone The GenBank/EMBL/DDBJ accession number for the nucleotide sequence reported in this paper, corresponding to a 6967 bp fragment, is AJ297885 .