A eukaryotic-type signalling system of Pseudomonas aeruginosa contributes to oxidative stress resistance, intracellular survival and virulence

BMC Genomics

Research Article

Jana Goldová¹  Pavel Branny¹  Aleš Ulrych¹  Kamil Hercík² 

[1] Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, 142 20 Prague 4, 1083, Vídeňská, Czech Republic;Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, 142 20 Prague 4, 1083, Vídeňská, Czech Republic;Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, 20892, Bethesda, MD, USA;

关键词: Trehalose;    Mutant Strain;    Quorum Sense;    Regulon;    Pseudomonas Quinolone Signal;   

DOI  :  10.1186/1471-2164-12-437

 received in 2011-02-21, accepted in 2011-08-31,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundThe genome of Pseudomonas aeruginosa contains at least three genes encoding eukaryotic-type Ser/Thr protein kinases, one of which, ppkA, has been implicated in P. aeruginosa virulence. Together with the adjacent pppA phosphatase gene, they belong to the type VI secretion system (H1-T6SS) locus, which is important for bacterial pathogenesis. To determine the biological function of this protein pair, we prepared a pppA-ppkA double mutant and characterised its phenotype and transcriptomic profiles.ResultsPhenotypic studies revealed that the mutant grew slower than the wild-type strain in minimal media and exhibited reduced secretion of pyoverdine. In addition, the mutant had altered sensitivity to oxidative and hyperosmotic stress conditions. Consequently, mutant cells had an impaired ability to survive in murine macrophages and an attenuated virulence in the plant model of infection. Whole-genome transcriptome analysis revealed that pppA-ppkA deletion affects the expression of oxidative stress-responsive genes, stationary phase σ-factor RpoS-regulated genes, and quorum-sensing regulons. The transcriptome of the pppA-ppkA mutant was also analysed under conditions of oxidative stress and showed an impaired response to the stress, manifested by a weaker induction of stress adaptation genes as well as the genes of the SOS regulon. In addition, expression of either RpoS-regulated genes or quorum-sensing-dependent genes was also affected. Complementation analysis confirmed that the transcription levels of the differentially expressed genes were specifically restored when the pppA and ppkA genes were expressed ectopically.ConclusionsOur results suggest that in addition to its crucial role in controlling the activity of P. aeruginosa H1-T6SS at the post-translational level, the PppA-PpkA pair also affects the transcription of stress-responsive genes. Based on these data, it is likely that the reduced virulence of the mutant strain results from an impaired ability to survive in the host due to the limited response to stress conditions.

【 授权许可】

Unknown   
© Goldová et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.