The stringent response of Staphylococcus aureus and its impact on survival after phagocytosis through the induction of intracellular PSMs expression

PLoS Pathog. 2012;8(11):e1003016. doi: 10.1371/journal.ppat.1003016. Epub 2012 Nov 29.


The stringent response is initiated by rapid (p)ppGpp synthesis, which leads to a profound reprogramming of gene expression in most bacteria. The stringent phenotype seems to be species specific and may be mediated by fundamentally different molecular mechanisms. In Staphylococcus aureus, (p)ppGpp synthesis upon amino acid deprivation is achieved through the synthase domain of the bifunctional enzyme RSH (RelA/SpoT homolog). In several firmicutes, a direct link between stringent response and the CodY regulon was proposed. Wild-type strain HG001, rsh(Syn), codY and rsh(Syn), codY double mutants were analyzed by transcriptome analysis to delineate different consequences of RSH-dependent (p)ppGpp synthesis after induction of the stringent response by amino-acid deprivation. Under these conditions genes coding for major components of the protein synthesis machinery and nucleotide metabolism were down-regulated only in rsh positive strains. Genes which became activated upon (p)ppGpp induction are mostly regulated indirectly via de-repression of the GTP-responsive repressor CodY. Only seven genes, including those coding for the cytotoxic phenol-soluble modulins (PSMs), were found to be up-regulated via RSH independently of CodY. qtRT-PCR analyses of hallmark genes of the stringent response indicate that an RSH activating stringent condition is induced after uptake of S. aureus in human polymorphonuclear neutrophils (PMNs). The RSH activity in turn is crucial for intracellular expression of psms. Accordingly, rsh(Syn) and rsh(Syn), codY mutants were less able to survive after phagocytosis similar to psm mutants. Intraphagosomal induction of psmα1-4 and/or psmβ1,2 could complement the survival of the rsh(Syn) mutant. Thus, an active RSH synthase is required for intracellular psm expression which contributes to survival after phagocytosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / immunology*
  • Base Sequence
  • Gene Expression Regulation, Bacterial / genetics
  • Gene Expression Regulation, Bacterial / immunology*
  • Humans
  • Ligases / genetics
  • Ligases / immunology*
  • Microbial Viability / genetics
  • Microbial Viability / immunology*
  • Molecular Sequence Data
  • Mutation
  • Neutrophils / immunology*
  • Neutrophils / microbiology
  • Phagocytosis / immunology*
  • Regulon / immunology
  • Repressor Proteins / genetics
  • Repressor Proteins / immunology*
  • Sheep
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / immunology*


  • Bacterial Proteins
  • CodY protein, Staphylococcus aureus
  • Repressor Proteins
  • Ligases
  • guanosine 3',5'-polyphosphate synthetases

Associated data

  • GENBANK/GSE99340

Grants and funding

The work was supported by grants to C. Wolz and M. Lalk from the Deutsche Forschungsgemeinschaft TR34. T. Geiger received a grant from the fortune program (2068-0-0) of the medical faculty of Tübingen. M. Liebeke was a recipient of a fellowship from the Alfred Krupp von Bohlen and Halbach-Stiftung: “A functional Genomics Approach in Infection Biology”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.