alamethicin and methyl-salicylate

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.

Topics: Alamethicin; Fabaceae; Plants, Medicinal; Salicylates; Signal Transduction; Terpenes