Quorum sensing control of Type VI secretion factors restricts the proliferation of quorum-sensing mutants

Elife. 2016 May 16;5:e14712. doi: 10.7554/eLife.14712.

Abstract

Burkholderia thailandensis uses acyl-homoserine lactone-mediated quorum sensing systems to regulate hundreds of genes. Here we show that cell-cell contact-dependent type VI secretion (T6S) toxin-immunity systems are among those activated by quorum sensing in B. thailandensis. We also demonstrate that T6S is required to constrain proliferation of quorum sensing mutants in colony cocultures of a BtaR1 quorum-sensing signal receptor mutant and its parent. However, the BtaR1 mutant is not constrained by and outcompetes its parent in broth coculture, presumably because no cell contact occurs and there is a metabolic cost associated with quorum sensing gene activation. The increased fitness of the wild type over the BtaR1 mutant during agar surface growth is dependent on an intact T6SS-1 apparatus. Thus, quorum sensing activates B. thailandensis T6SS-1 growth inhibition and this control serves to police and constrain quorum-sensing mutants. This work defines a novel role for T6SSs in intraspecies mutant control.

Keywords: cheater control; contact-dependent inhibition; infectious disease; microbiology; sociomicrobiology; toxin-immunity factors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Acyl-Butyrolactones / metabolism
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Burkholderia / genetics*
  • Burkholderia / growth & development
  • Burkholderia / metabolism
  • Colony Count, Microbial
  • Culture Media / chemistry
  • Gene Expression Regulation, Bacterial*
  • Genetic Fitness
  • Multigene Family
  • Mutation
  • Quorum Sensing*
  • Receptors, Cell Surface / genetics*
  • Receptors, Cell Surface / metabolism
  • Type IV Secretion Systems / genetics*
  • Type IV Secretion Systems / metabolism

Substances

  • Acyl-Butyrolactones
  • Bacterial Proteins
  • Culture Media
  • Receptors, Cell Surface
  • Type IV Secretion Systems