title: Perturbation of the two-component signal transduction system, BprRS, results in attenuated virulence and motility defects in Burkholderia pseudomallei.
abstract: Burkholderia pseudomallei is the causative agent of melioidosis, a severe invasive disease of humans and animals. Initial screening of a B. pseudomallei signature-tagged mutagenesis library identified an attenuated mutant with a transposon insertion in a gene encoding the sensor component of an uncharacterised two-component signal transduction system (TCSTS), which we designated BprRS.
  
  
  
  Single gene inactivation of either the response regulator gene (bprR) or the sensor histidine kinase gene (bprS) resulted in mutants with reduced swarming motility and reduced virulence in mice. However, a bprRS double mutant was not attenuated for virulence and displayed wild-type levels of motility. The transcriptomes of the bprS, bprR and bprRS mutants were compared with the transcriptome of the parent strain K96243. Inactivation of the entire BprRS TCSTS (bprRS double mutant) resulted in altered expression of only nine genes, including both bprR and bprS, five phage-related genes and bpss0686, encoding a putative 5, 10-methylene tetrahydromethanopterin reductase involved in one carbon metabolism. In contrast, the transcriptomes of each of the bprR and bprS single gene mutants revealed more than 70 differentially expressed genes common to both mutants, including regulatory genes and those required for flagella assembly and for the biosynthesis of the cytotoxic polyketide, malleilactone.
  
  
  
  Inactivation of the entire BprRS TCSTS did not alter virulence or motility and very few genes were differentially expressed indicating that the definitive BprRS regulon is relatively small. However, loss of a single component, either the sensor histidine kinase BprS or its cognate response regulator BprR, resulted in significant transcriptomic and phenotypic differences from the wild-type strain. We hypothesize that the dramatically altered phenotypes of these single mutants are the result of cross-regulation with one or more other TCSTSs and concomitant dysregulation of other key regulatory genes.
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Core Biotechnology Services, University of Leicester, Leicester, LE1 9HN, UK.
authors.forename: Natalie R
authors.initials: NR
authors.lastname: Lazar Adler
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Allwood
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.
authors.forename: Deanna
authors.initials: D
authors.lastname: Deveson Lucas
authors.affiliation: Victorian Bioinformatics Platform, Monash University, Victoria, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Harrison
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Watts
authors.affiliation: Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.|Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Dimitropoulos
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
authors.forename: Puthayalai
authors.initials: P
authors.lastname: Treerat
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Faculty of Dentistry, National University of Singapore, Singapore, Singapore.
authors.forename: Priyangi
authors.initials: P
authors.lastname: Alwis
authors.affiliation: Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.|Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia.
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Devenish
authors.affiliation: Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.|Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Prescott
authors.affiliation: Department of Microbiology and Immunology, James Cook University, Townsville, Queensland, Australia.
authors.forename: Brenda
authors.initials: B
authors.lastname: Govan
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.|Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia.
authors.forename: Marina
authors.initials: M
authors.lastname: Harper
authors.affiliation: Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria, 3800, Australia. john.boyce@monash.edu.|Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Victoria, Australia. john.boyce@monash.edu.
authors.forename: John D
authors.initials: JD
authors.lastname: Boyce
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D016957:Burkholderia pseudomallei / Q000235:genetics / Q000472:pathogenicity*; D020869:Gene Expression Profiling / Q000379:methods*; D015964:Gene Expression Regulation, Bacterial; D015966:Gene Expression Regulation, Fungal; D053263:Gene Regulatory Networks; D009154:Mutation; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors
keywords: Burkholderia pseudomallei; Flagella; Transcriptomics; Two-component signal transduction; Virulence