title: Differential signalling and plant-volatile biosynthesis.
abstract: At least two different signalling pathways have been identified that result in clearly distinguishable volatile profiles in response to pathogens and herbivores in the lima bean Phaseolus lunatus. Alamethicin, a voltage-gated ion-channel-forming peptide from Trichoderma viride, is a potent inducer of volatile biosynthesis in the lima bean. Unlike elicitation with cellulysin or herbivore damage, which act through the jasmonic acid pathway and result in a complex pattern of volatile compounds, the emitted blend comprises only the two homoterpens, 4,11-dimethylnona-1,3,7-triene and 4,8,12-trimethyltrideca-1,3,7,11-tetraene, and methyl salicylate. Both pathways, represented by jasmonic acid and alamethicin, depend on lipid-derived signalling compounds, set off by the activation of a phospholipase A and further processing by lipoxygenase activity. The alamethicin-induced signal-transduction pathway interferes with the octadecanoid cascade, probably due to increased salicylic acid levels, resulting in an inhibition of the typical jasmonic acid-induced volatile profile.
authors.affiliation: Max Planck Institute of Chemical Ecology, Department of Bioorganics, Carl Zeiss Promenade 10, 07745 Jena, Germany. engelberth@ice.mpg.de
authors.forename: J
authors.initials: J
authors.lastname: Engelberth
mesh_terms: D000408:Alamethicin / Q000494:pharmacology*; D007887:Fabaceae / Q000187:drug effects / Q000502:physiology*; D010946:Plants, Medicinal; D012459:Salicylates / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013729:Terpenes / Q000378:metabolism*
chemical_list: C411254:4,8-dimethyl-1,3,7-nonatriene; D012459:Salicylates; D013729:Terpenes; D000408:Alamethicin; C033069:methyl salicylate