Indole as an intercellular signal in microbial communities

FEMS Microbiol Rev. 2010 Jul;34(4):426-44. doi: 10.1111/j.1574-6976.2009.00204.x. Epub 2009 Dec 15.


Bacteria can utilize signal molecules to coordinate their behavior to survive in dynamic multispecies communities. Indole is widespread in the natural environment, as a variety of both Gram-positive and Gram-negative bacteria (to date, 85 species) produce large quantities of indole. Although it has been known for over 100 years that many bacteria produce indole, the real biological roles of this molecule are only now beginning to be unveiled. As an intercellular signal molecule, indole controls diverse aspects of bacterial physiology, such as spore formation, plasmid stability, drug resistance, biofilm formation, and virulence in indole-producing bacteria. In contrast, many non-indole-producing bacteria, plants and animals produce diverse oxygenases which may interfere with indole signaling. It appears indole plays an important role in bacterial physiology, ecological balance, and possibly human health. Here we discuss our current knowledge and perspectives on indole signaling.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacteria / growth & development
  • Bacteria / metabolism*
  • Bacterial Physiological Phenomena*
  • Biofilms / growth & development
  • Drug Resistance, Bacterial
  • Gene Expression Regulation, Bacterial
  • Indoles / metabolism*
  • Plasmids
  • Quorum Sensing*
  • Signal Transduction*
  • Virulence


  • Indoles
  • indole