Coronatine promotes Pseudomonas syringae virulence in plants by activating a signaling cascade that inhibits salicylic acid accumulation

Cell Host Microbe. 2012 Jun 14;11(6):587-96. doi: 10.1016/j.chom.2012.04.014.


Phytopathogens can manipulate plant hormone signaling to access nutrients and counteract defense responses. Pseudomonas syringae produces coronatine, a toxin that mimics the plant hormone jasmonic acid isoleucine and promotes opening of stomata for bacterial entry, bacterial growth in the apoplast, systemic susceptibility, and disease symptoms. We examined the mechanisms underlying coronatine-mediated virulence and show that coronatine activates three homologous NAC transcription factor (TF) genes, ANAC019, ANAC055, and ANAC072, through direct activity of the TF, MYC2. Genetic characterization of NAC TF mutants demonstrates that these TFs mediate coronatine-induced stomatal reopening and bacterial propagation in both local and systemic tissues by inhibiting the accumulation of the key plant immune signal salicylic acid (SA). These NAC TFs exert this inhibitory effect by repressing ICS1 and activating BSMT1, genes involved in SA biosynthesis and metabolism, respectively. Thus, a signaling cascade by which coronatine confers its multiple virulence activities has been elucidated.

Publication types

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

MeSH terms

  • Amino Acids / toxicity*
  • Arabidopsis / microbiology
  • Indenes / toxicity*
  • Plant Diseases / microbiology*
  • Plant Proteins / metabolism
  • Pseudomonas syringae / metabolism
  • Pseudomonas syringae / pathogenicity*
  • Salicylic Acid / metabolism*
  • Signal Transduction*
  • Transcriptional Activation
  • Virulence
  • Virulence Factors / toxicity*


  • Amino Acids
  • Indenes
  • Plant Proteins
  • Virulence Factors
  • coronatine
  • Salicylic Acid