A novel widespread interkingdom signaling circuit

Trends Plant Sci. 2013 Mar;18(3):167-74. doi: 10.1016/j.tplants.2012.09.007. Epub 2012 Oct 22.


Extensive communication is believed to occur between eukaryotes and prokaryotes via signaling molecules; this field of research is now called interkingdom signaling. Recently, it has been discovered that many different plant-associated bacteria possess a protein closely related to the quorum-sensing (QS) LuxR-family protein that binds and responds to plant compounds. This LuxR protein does not have a cognate N-acyl homoserine lactone (AHL) signal synthase and therefore is regarded as a 'solo' or 'orphan'. The protein is involved in interkingdom signaling in rhizobia, xanthomonads, and pseudomonads, regulating processes important for plant-bacteria interaction. In this review, we focus on this new interkingdom signaling circuit, which is widespread among pathogenic and beneficial plant-associated bacteria.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Bacteria / genetics*
  • Bacterial Physiological Phenomena*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Host-Pathogen Interactions
  • Molecular Sequence Data
  • Phylogeny
  • Plant Physiological Phenomena*
  • Plants / microbiology*
  • Quorum Sensing / genetics
  • Repressor Proteins / genetics
  • Sequence Alignment
  • Signal Transduction / physiology*
  • Symbiosis
  • Trans-Activators / genetics


  • Bacterial Proteins
  • Repressor Proteins
  • Trans-Activators
  • LuxR autoinducer binding proteins