Role of PvdQ in Pseudomonas aeruginosa virulence under iron-limiting conditions.
PvdQ, an acylase from Pseudomonas aeruginosa PAO1, has been shown to have at least two functions. It can act as a quorum quencher due to its ability to degrade long-chain N-acylhomoserine lactones (AHLs), e.g. 3-oxo-C12-HSL, leading to a decrease in virulence factors. In addition, PvdQ is involved in iron homeostasis by playing a role in the biosynthesis of pyoverdine, the major siderophore of P. aeruginosa. In accordance with earlier studies on RNA level, we could show at the protein level that PvdQ is only expressed when iron is present at very low concentrations. We therefore set out to investigate the two functions of PvdQ under iron-limiting conditions. Gene deletion of pvdQ does not affect growth of P. aeruginosa but abrogates pyoverdine production, and results in an accumulation of 3-oxo-C12-HSL. Phenotypic analyses of our DeltapvdQ mutant at low iron concentrations revealed that this mutant is impaired in swarming motility and biofilm formation. Additionally, a plant and a Caenorhabditis elegans infection model demonstrated that the deletion of pvdQ resulted in reduced virulence. None of the phenotypes in the present study could be linked to the presence or absence of AHLs. These results clearly indicate that under iron-limiting conditions PvdQ plays a major role in swarming motility, in biofilm development and in infection that is more likely to be linked to the pyoverdine pathway rather than the LasI/LasR/3-oxo-C12-HSL quorum-sensing circuit.
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Pol Nadal
PN
Jimenez
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Gudrun
G
Koch
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Evelina
E
Papaioannou
Faculty of Pharmacy and Faculty of Technobiology, University of Surabaya, Indonesia.|Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Mariana
M
Wahjudi
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Joanna
J
Krzeslak
Laboratory for Pharmaceutical Microbiology, Ghent University, 9000 Ghent, Belgium.
Tom
T
Coenye
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Robbert H
RH
Cool
Department of Pharmaceutical Biology, University of Groningen, 9713 AV Groningen, The Netherlands.
Wim J
WJ
Quax
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000096:biosynthesis; D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D017173:Caenorhabditis elegans / Q000382:microbiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006714:Homoserine / Q000031:analogs & derivatives / Q000096:biosynthesis; D007501:Iron / Q000378:metabolism*; D009842:Oligopeptides / Q000096:biosynthesis; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D011198:Solanum tuberosum / Q000382:microbiology; D014774:Virulence
D001426:Bacterial Proteins; C109860:N-(3-oxododecanoyl)homoserine lactone; D009842:Oligopeptides; D006714:Homoserine; C042453:pyoverdin; D007501:Iron; D000581:Amidohydrolases; C019665:amidase; D015107:4-Butyrolactone