The herbivore-induced plant volatile tetradecane enhances plant resistance to Holotrichia parallela larvae in maize roots

BACKGROUND Many herbivore-induced volatiles have been proven to act as signaling compounds to regulate nearby plant defense responses. However, the precise roles of key volatiles produced by maize roots after Holotrichia parallela larva feeding remain largely unknown. RESULTS We investigated changes in phytohormones and volatiles in maize roots after H. parallela larval infestation. Marked increases in the phytohormone jasmonic acid (JA) and the volatiles jasmone and tetradecane were induced by herbivores, whereas the salicylic acid content decreased. In addition, pre-exposure to tetradecane markedly increased the levels of the stress hormone JA, its precursors and derivatives, and related gene expression. In addition, pre-exposure altered the production of defensive benzoxazinoid secondary metabolites, resulting in increased plant resistance to H. parallela larvae. Plants pre-exposed to jasmone did not differ from control plants. In addition, bioassays showed that H. parallela larval growth was suppressed by feeding maize roots after pre-exposure to tetradecane. CONCLUSION These results demonstrate that tetradecane may function as a potent defense induction signal that prepares neighboring plants for incoming attacks.