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

Gwendoline Gicquel (1) , Emeline Bouffartigues (1) , Manjeet Bains (2) , Virginie Oxaran (1) , Thibaut Rosay (1) , Olivier Lesouhaitier (1) , Nathalie Connil (1) , Alexis Bazire (3) , Olivier Maillot (1) , Magalie Bénard (4) , Pierre Cornelis (5) , Robert E W Hancock (2) , Alain Dufour (3) , Marc G J Feuilloley (1) , Nicole Orange (1) , Eric Déziel (6) , Sylvie Chevalier (1)

1 LMDF-SME - Laboratoire de Microbiologie du Froid – Signaux et Micro-Environnement
2 Centre for Microbal Diseases and Immunity Research
3 LBCM - Laboratoire de Biotechnologie et Chimie Marines
4 PRIMACEN - Plate-Forme de Recherche en Imagerie Cellulaire de Haute-Normandie
5 Department of Bioengineering Sciences, Research group Microbiology, VIB Department of Structural Biology
6 INRS-IAF - Institut Armand Frappier

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.

Domains: Bacteriology; Genetics

Gwendoline Gicquel, Emeline Bouffartigues, Manjeet Bains, Virginie Oxaran, Thibaut Rosay, et al.. The extra-cytoplasmic function sigma factor sigX modulates biofilm and virulence-related properties in Pseudomonas aeruginosa.. PLoS ONE, 2012, 8 (11), pp.e80407. ⟨10.1371/journal.pone.0080407⟩. ⟨pasteur-01131037⟩