Cis-jasmone inhibits lipoxygenase pathway and induces defense of tomato plant against chewing herbivore

The role of cis-jasmone as a semiochemical and inducer of plant defenses is well documented in the literature.  However, the mechanisms by which cis-jasmone mediate plant-insect and multitrophic interactions are poorly understood. Here, we hypothesized that foliar applications of cis-jasmone will alter the lipoxygenase pathway with important consequences for plant-insect interactions. To test the hypothesis, we characterized the volatile organic compound (VOC) profile of cis-jasmone-treated tomato plants and determined the feeding response of Spodoptera exigua larvae on treated plants.  Gas chromatograph coupled-mass spectrometry (GC-MS) results showed that emission of plant VOCs, including green leaf volatiles, was suppressed in cis-jasmone-treated plants compared to untreated plants. Spodoptera exigua larvae showed reduced feeding and lower weight gain on cis-jasmone-treated plants. To our knowledge, this is the first report which showed that exogenous application of cis-jasmone inhibited emission of plant VOCs. The implication of this finding should be considered especially in the augmented use of cis-jasmone to manage agricultural pests, since many herbivores and their natural enemies are known to use plant VOCs as host location cues.