Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The Netherlands.
Oecologia. 2010 Feb;162(2):393-404. doi: 10.1007/s00442-009-1459-x. Epub 2009 Oct 6.
Herbivore-induced plant defences influence the behaviour of insects associated with the plant. For biting-chewing herbivores the octadecanoid signal-transduction pathway has been suggested to play a key role in induced plant defence. To test this hypothesis in our plant-herbivore-parasitoid tritrophic system, we used phenidone, an inhibitor of the enzyme lipoxygenase (LOX), that catalyses the initial step in the octadecanoid pathway. Phenidone treatment of Brussels sprouts plants reduced the accumulation of internal signalling compounds in the octadecanoid pathway downstream of the step catalysed by LOX, i.e. 12-oxo-phytodienoic acid (OPDA) and jasmonic acid. The attraction of Cotesia glomerata parasitoids to host-infested plants was significantly reduced by phenidone treatment. The three herbivores investigated, i.e. the specialists Plutella xylostella, Pieris brassicae and Pieris rapae, showed different oviposition preferences for intact and infested plants, and for two species their preference for either intact or infested plants was shown to be LOX dependent. Our results show that phenidone inhibits the LOX-dependent defence response of the plant and that this inhibition can influence the behaviour of members of the associated insect community.
食草动物诱导的植物防御会影响与植物相关的昆虫的行为。对于啃食性食草动物，已经提出十八碳烯信号转导途径在诱导植物防御中发挥关键作用。为了在我们的植物-草食动物-寄生性天敌三重生态系统中检验这一假设，我们使用了苯并恶唑酮，一种脂氧合酶（LOX）的抑制剂，它催化十八碳烯途径的初始步骤。苯并恶唑酮处理布鲁塞尔芽甘蓝植物减少了 LOX 催化步骤下游十八碳烯途径中内部信号化合物的积累，即 12-氧代-植二烯酸（OPDA）和茉莉酸。苯并恶唑酮处理显著降低了菜粉蝶寄生蜂 Cotesia glomerata 对受宿主侵染植物的吸引力。研究的三种草食动物，即小菜蛾、菜粉蝶和甘蓝夜蛾，对完整和受侵染植物表现出不同的产卵偏好，并且对于两种物种，它们对完整或受侵染植物的偏好被证明依赖于 LOX。我们的结果表明，苯并恶唑酮抑制了植物的 LOX 依赖防御反应，这种抑制可以影响相关昆虫群落成员的行为。
