Subterranean Herbivore-induced Volatiles Released by Citrus Roots upon Feeding by Diaprepes abbreviatus Recruit Entomopathogenic Nematodes
Subterranean Herbivore-induced Volatiles Released by Citrus Roots upon Feeding by Diaprepes abbreviatus Recruit Entomopathogenic Nematodes
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DOI：
10.1007/s10886-010-9773-7
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发表时间：
2010-04-01
影响因子：
2.3
通讯作者：
Stelinski, Lukasz L.
中科院分区：
文献类型：
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作者：
Ali, Jared G.;Alborn, Hans T.;Stelinski, Lukasz L.
食草动物诱导的挥发性排放物通过招募食草昆虫的天敌而有利于植物宿主。这种三营养相互作用已经在地上陆地环境中进行了彻底的研究。最近，在地下环境中也发现了类似的信号，这可能对植物的间接防御同样重要。根象甲（Diaprepes缩写）的幼虫是柑橘的严重害虫。虫害可以通过使用昆虫病原线虫来控制，但植物、昆虫和线虫之间的相互作用知之甚少，并且仍然不可预测。在使用根区六臂嗅觉计的生物测定中，当被根象鼻虫幼虫侵染时，柑橘根（'Swingle citrumelo' rootstock）比未侵染的根招募了更多的昆虫病原线虫（steinerma diaprepesi）。受侵染植物对线虫的吸引力大于单独的幼虫。被象鼻虫幼虫破坏的根系比机械损坏的根系和防沙措施吸引更多的线虫。通过对土壤挥发物的动态原位采集和GC-MS分析，我们确定了侵染植物根系产生的四种主要萜烯化合物，而这些化合物在未侵染植物根系或仅含幼虫的土壤中没有发现。在二选沙柱生物测定中，被象鼻虫侵染的根的溶剂提取物比未被象鼻虫侵染的根的溶剂提取物吸引更多的线虫。这些发现表明，单柑橘根释放诱导挥发物作为对食草动物摄食的间接防御，其中一些诱导挥发物具有引诱昆虫病原线虫的作用。
Herbivore-induced volatile emissions benefit plant hosts by recruiting natural enemies of herbivorous insects. Such tritrophic interactions have been examined thoroughly in the above-ground terrestrial environment. Recently, similar signals have also been described in the subterranean environment, which may be of equal importance for indirect plant defense. The larvae of the root weevil, Diaprepes abbreviates, are a serious pest of citrus. Infestations can be controlled by the use of entomopathogenic nematodes, yet the interactions between the plant, insect and nematode are poorly understood and remain unpredictable. In bioassays that used a root zone six-arm olfactometer, citrus roots ('Swingle citrumelo' rootstock) recruited significantly more entomopathogenic nematodes (Steinernema diaprepesi) when infested with root weevil larvae than non-infested roots. Infested plants were more attractive to nematodes than larvae alone. Roots damaged by weevil larvae attracted more nematodes than mechanically damaged roots and sand controls. By dynamic in situ collection and GC-MS analysis of volatiles from soil, we determined that four major terpene compounds were produced by infested plant roots that were not found in samples from non-infested roots or soil that contained only larvae. Solvent extracts of weevil-infested roots attracted more nematodes than extracts of non-infested roots in a two choice sand-column bioassay. These findings suggest that Swingle citrus roots release induced volatiles as an indirect defense in response to herbivore feeding, and that some of these induced volatiles function as attractants for entomopathogenic nematodes.