Present address: Molecular Genetics Section, Agriculture and Agri-Food Canada Research Station, 107 Science Place, Saskatoon, Saskatchewan, Canada, S7N 0X2.
C6-volatiles derived from the lipoxygenase pathway induce a subset of defense-related genes
Article first published online: 25 DEC 2001
The Plant Journal
Volume 16, Issue 5, pages 561–569, December 1998
How to Cite
Bate, N. J. and Rothstein, S. J. (1998), C6-volatiles derived from the lipoxygenase pathway induce a subset of defense-related genes. The Plant Journal, 16: 561–569. doi: 10.1046/j.1365-313x.1998.00324.x
- Issue published online: 25 DEC 2001
- Article first published online: 25 DEC 2001
- Received 3 July 1998; revised 8 October 1998; accepted 13 October 1998.
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 ofArabidopsisseedlings with 10 μM 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 resistantArabidopsismutant, 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 inArabidopsisseedlings. 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.