N-hydroxypipecolic acid and salicylic acid: a metabolic duo for systemic acquired resistance

Curr Opin Plant Biol. 2019 Aug;50:44-57. doi: 10.1016/j.pbi.2019.02.006. Epub 2019 Mar 27.


Recent research has established that the pipecolate pathway, a three-step biochemical sequence from l-lysine to N-hydroxypipecolic acid (NHP), is central for plant systemic acquired resistance (SAR). NHP orchestrates SAR establishment in concert with the immune signal salicylic acid (SA). Here, we outline the biochemistry of NHP formation from l-Lys and address novel progress on SA biosynthesis in Arabidopsis and other plant species. In Arabidopsis, the pathogen-inducible pipecolate and salicylate pathways are activated by common and distinct regulatory elements and mutual interactions between both metabolic branches exist. The mode of action of NHP in SAR involves direct induction of SAR gene expression, signal amplification, priming for enhanced defense activation and positive interplay with SA signaling to ensure elevated plant immunity.

Publication types

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

MeSH terms

  • Arabidopsis Proteins*
  • Arabidopsis*
  • Gene Expression Regulation, Plant
  • Pipecolic Acids
  • Plant Diseases
  • Plant Immunity
  • Salicylic Acid


  • Arabidopsis Proteins
  • N-hydroxypipecolic acid
  • Pipecolic Acids
  • Salicylic Acid