The extra-cytoplasmic function sigma factor sigX modulates biofilm and virulence-related properties in Pseudomonas aeruginosa

• Published in: PloS one Vol. 8; no. 11; p. e80407
• Main Authors: Gicquel, Gwendoline, Bouffartigues, Emeline, Bains, Manjeet, Oxaran, Virginie, Rosay, Thibaut, Lesouhaitier, Olivier, Connil, Nathalie, Bazire, Alexis, Maillot, Olivier, Bénard, Magalie, Cornelis, Pierre, Hancock, Robert E W, Dufour, Alain, Feuilloley, Marc G J, Orange, Nicole, Déziel, Eric, Chevalier, Sylvie
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.11.2013; Public Library of Science (PLoS)
• Subjects: Antibiotic resistance; Antibiotics; Bacillus subtilis; Bacteria; Bacterial proteins; Bacterial Proteins - genetics; Bacteriology; Biofilms; Caco-2 Cells; Cell Line, Tumor; Chaperones; Comparative analysis; Cross infection; Cystic fibrosis; Cytoplasm - genetics; Energy metabolism; Energy Metabolism - genetics; Genes; Genetic aspects; Genetics; Genomes; Heat shock proteins; Humans; Hybridization; Life Sciences; Major outer membrane protein; Membrane proteins; Metabolism; Microbial drug resistance; Microbiology and Parasitology; Mutants; Mutation - genetics; Nosocomial infections; Porphyromonas gingivalis; Protein transport; Protein turnover; Proteins; Pseudomonas aeruginosa; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - physiology; RNA polymerase; Secretion; Shock resistance; Sigma factor; Sigma Factor - genetics; Signal transduction; Transcription; Transcription (Genetics); Transcription, Genetic - genetics; Transcriptome - genetics; Virulence; Virulence - genetics; Virulence Factors - genetics; British Columbia Canada; France; Canada
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0080407

SigX, one of the 19 extra-cytoplasmic function sigma factors of P. aeruginosa, was only known to be involved in transcription of the gene encoding the major outer membrane protein OprF. We conducted a comparative transcriptomic study between the wildtype H103 strain and its sigX mutant PAOSX, which revealed a total of 307 differentially expressed genes that differed by more than 2 fold. Most dysregulated genes belonged to six functional classes, including the "chaperones and heat shock proteins", "antibiotic resistance and susceptibility", "energy metabolism", "protein secretion/export apparatus", and "secreted factors", and "motility and attachment" classes. In this latter class, the large majority of the affected genes were down-regulated in the sigX mutant. In agreement with the array data, the sigX mutant was shown to demonstrate substantially reduced motility, attachment to biotic and abiotic surfaces, and biofilm formation. In addition, virulence towards the nematode Caenorhabditis elegans was reduced in the sigX mutant, suggesting that SigX is involved in virulence-related phenotypes.