The salicylic acid loop in plant defense

Curr Opin Plant Biol. 2003 Aug;6(4):365-71. doi: 10.1016/s1369-5266(03)00058-x.


Salicylic acid is an important signal molecule in plant defense. In the past two years, significant progress has been made in understanding the mechanism of salicylic-acid biosynthesis and signaling in plants. A pathway similar to that found in some bacteria synthesizes salicylic acid from chorismate via isochorismate. Salicylic-acid signaling is mediated by at least two mechanisms, one requiring the NON-EXPRESSOR OF PR1 (NPR1) gene and a second that is independent of NPR1. Feedback loops involving salicylic acid modulate upstream signals. These feedback loops may provide a point for integrating developmental, environmental and other defense-associated signals, and thus fine-tune the defense responses of plants.

Publication types

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

MeSH terms

  • Arabidopsis Proteins / physiology
  • Plant Physiological Phenomena*
  • Salicylic Acid / metabolism*


  • Arabidopsis Proteins
  • NPR1 protein, Arabidopsis
  • Salicylic Acid