Interspecies signalling via the Stenotrophomonas maltophilia diffusible signal factor influences biofilm formation and polymyxin tolerance in Pseudomonas aeruginosa

Mol Microbiol. 2008 Apr;68(1):75-86. doi: 10.1111/j.1365-2958.2008.06132.x. Epub 2008 Feb 28.


Interspecies signalling through the action of diffusible signal molecules can influence the behaviour of organisms growing in polymicrobial communities. Stenotrophomonas maltophilia and Pseudomonas aeruginosa occur ubiquitously in the environment and can be found together in diverse niches including the rhizosphere of plants and the cystic fibrosis lung. In mixed species biofilms, S. maltophilia substantially influenced the architecture of P. aeruginosa structures, which developed as extended filaments. This effect depended upon the synthesis of the diffusible signal factor (DSF) by S. maltophilia and could be mimicked by the addition of synthetic DSF. This response of P. aeruginosa to DSF required PA1396, a sensor kinase with an input domain of related amino acid sequence to the sensory input domain of RpfC, which is responsible for DSF perception in xanthomonads. Mutation of PA1396 or addition of DSF to P. aeruginosa led to increased levels of a number of proteins with roles in bacterial stress tolerance, including those implicated in resistance to cationic antimicrobial peptides. This effect was associated with increased tolerance to polymyxins. Homologues of PA1396 occur in a number of phytopathogenic and plant-associated pseudomonads, suggesting that modulation of bacterial behaviour through DSF-mediated interspecies signalling with xanthomonads is a phenomenon that occurs widely.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology
  • Biofilms / growth & development*
  • Drug Resistance, Bacterial
  • Molecular Sequence Data
  • Mutation
  • Polymyxins / pharmacology*
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / growth & development
  • Pseudomonas aeruginosa / metabolism
  • Sequence Homology, Amino Acid
  • Signal Transduction / genetics
  • Signal Transduction / physiology*
  • Stenotrophomonas maltophilia / genetics
  • Stenotrophomonas maltophilia / metabolism*


  • Bacterial Proteins
  • Polymyxins