C6-volatiles derived from the lipoxygenase pathway induce a subset of defense-related genes

Plant J. 1998 Dec;16(5):561-9. doi: 10.1046/j.1365-313x.1998.00324.x.


Six-Carbon (C6-) volatiles, including the aldehydes trans-2-hexenal, hexanal and cis-3-hexenal, as well as their corresponding alcohols, are produced from damaged or wounded plant tissue as a product of the enzymatic activity of hydroperoxide lyase (HPL), a component of the lipoxygenase (LOX) pathway. Aerial treatment of Arabidopsis seedlings with 10 microM concentrations of trans-2-hexenal induces several genes known to be involved in the plant's defense response, including phenylpropanoid-related genes as well as genes of the LOX pathway. Genes encoding the pathogenesis-related proteins PR-1 or PR-2, however, were not induced. Trans-2-hexenal induction thus closely mimics the group of genes induced by methyl jasmonate (MeJA), also a LOX-derived volatile. However, unlike MeJA, trans-2-hexenal did not induce hydroxymethylglutaryl-coenzyme A reductase (HMGR) or thionin2-1. The inductive effect seemed to be limited to C6-related volatiles, as C8-, C9- and other related volatiles did not induce LOX mRNA levels. As has been demonstrated for MeJA, trans-2-hexenal quantitatively reduced wild-type seed germination. Trans-2-hexenal also reduced the germination frequency of the MeJA resistant Arabidopsis mutant, jar1-1, supporting the notion that trans-2-hexenal and MeJA are recognized via different mechanisms. In addition, trans-2-hexenal had a moderate inhibitory effect on root length relative to similar concentrations of MeJA and was approximately 10-fold less effective than MeJA at inducing anthocyanin accumulation in Arabidopsis seedlings. These results suggest that C6-volatiles of the LOX pathway act as a wound signal in plants, but result in a moderate plant response relative to MeJA at both the physiological and molecular level.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Acetates / pharmacology
  • Aldehydes / metabolism
  • Aldehydes / pharmacology
  • Anthocyanins / metabolism
  • Arabidopsis / drug effects
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Base Sequence
  • Cyclopentanes / metabolism
  • Cyclopentanes / pharmacology
  • DNA Primers / genetics
  • Gene Expression Regulation, Plant / drug effects
  • Genes, Plant*
  • Hexanols / metabolism
  • Hexanols / pharmacology
  • Lipoxygenase / metabolism*
  • Oxylipins
  • Signal Transduction


  • Acetates
  • Aldehydes
  • Anthocyanins
  • Cyclopentanes
  • DNA Primers
  • Hexanols
  • Oxylipins
  • 2-hexenal
  • methyl jasmonate
  • Lipoxygenase