Pseudomonas syringae effector AvrPto blocks innate immunity by targeting receptor kinases

Curr Biol. 2008 Jan 8;18(1):74-80. doi: 10.1016/j.cub.2007.12.020. Epub 2007 Dec 27.


Plants use receptor kinases, such as FLS2 and EFR, to perceive bacterial pathogens and initiate innate immunity. This immunity is often suppressed by bacterial effectors, allowing pathogen propagation. To counteract, plants have evolved disease resistance genes that detect the bacterial effectors and reinstate resistance. The Pseudomonas syringae effector AvrPto promotes infection in susceptible plants but triggers resistance in plants carrying the protein kinase Pto and the associated resistance protein Prf. Here we show that AvrPto binds receptor kinases, including Arabidopsis FLS2 and EFR and tomato LeFLS2, to block plant immune responses in the plant cell. The ability to target receptor kinases is required for the virulence function of AvrPto in plants. The FLS2-AvrPto interaction and Pto-AvrPto interaction appear to share similar sequence requirements, and Pto competes with FLS2 for AvrPto binding. The results suggest that the mechanism by which AvrPto recognizes virulence targets is linked to the evolution of Pto, which, in association with Prf, recognizes the bacterium and triggers strong resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology
  • Arabidopsis / microbiology*
  • Arabidopsis Proteins / metabolism*
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology*
  • Immunity, Innate / genetics
  • MAP Kinase Signaling System
  • Plant Proteins / metabolism*
  • Protein Interaction Mapping
  • Protein Kinases / metabolism*
  • Protein Serine-Threonine Kinases / metabolism
  • Pseudomonas syringae / immunology
  • Pseudomonas syringae / pathogenicity*
  • Solanum lycopersicum / enzymology
  • Solanum lycopersicum / microbiology*
  • Virulence Factors / metabolism
  • Virulence Factors / physiology


  • Arabidopsis Proteins
  • Bacterial Proteins
  • Plant Proteins
  • Prf protein, Lycopersicon esculentum
  • Virulence Factors
  • avrPto protein, Pseudomonas syringae
  • Protein Kinases
  • FLS2 protein, Arabidopsis
  • Pto protein, Lycopersicon
  • Protein Serine-Threonine Kinases