Entomology and Nematology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA.
J Chem Ecol. 2013 Aug;39(8):1140-7. doi: 10.1007/s10886-013-0332-x. Epub 2013 Aug 8.
Plants defend themselves against herbivores both directly (chemical toxins and physical barriers) and indirectly (attracting natural enemies of their herbivores). Previous work has shown that plant roots of citrus defend against root herbivores by releasing an herbivore-induced plant volatile (HIPV), pregeijerene (1,5-dimethylcyclodeca-1,5,7-triene), that attracts naturally occurring entomopathogenic nematodes (EPNs) to Diaprepes abbreviatus larvae when applied in the field. However, the soil community is complex and contains a diversity of interspecific relationships that modulate food web assemblages. Herein, we tested the hypothesis that other nematode types beyond EPNs, as well as, nematophagous fungi are affected by the same HIPV that attracts EPNs to herbivore-damaged roots. We employed molecular probes designed to detect and quantify nematodes from the Acrobeloides-group (free-living bacterivorous nematodes, FLBNs), some of which compete with EPNs by 'hyperparasitizing' insect cadavers, and five species of nematophagous fungi (NF), which attack and kill EPNs. In two different agricultural systems (citrus and blueberry), we detected diverse species of nematodes and fungi; however, only the behavior of FLBNs was affected in a manner similar to that reported previously for EPNs. Although detected, NF abundance was not statistically affected by the presence of the belowground HIPV. We provide the first evidence showing subterranean HIPVs behave much the same as those aboveground, attracting not only parasitoids, but also hyperparasites and other food web members.
植物通过直接（化学毒素和物理屏障）和间接（吸引食草动物的天敌）方式来防御草食动物。之前的研究表明，柑橘类植物的根通过释放一种食草动物诱导的植物挥发物（HIPV）——pregeijerene（1,5-二甲基环癸-1,5,7-三烯），来防御根食草动物，当在田间应用时，这种 HIPV 会吸引自然发生的昆虫病原线虫（EPNs）到 Diaprepes abbreviatus 幼虫身上。然而，土壤群落非常复杂，包含多种种间关系，这些关系调节着食物网的组成。在此，我们检验了这样一个假设，即除 EPNs 以外的其他线虫类型，以及食线虫真菌，都会受到吸引 EPNs 到受草食动物损害的根部的相同 HIPV 的影响。我们使用了设计用来检测和量化 Acrobeloides 组（自由生活的细菌食性线虫，FLBNs）线虫的分子探针，其中一些通过“超寄生”昆虫尸体与 EPNs 竞争，以及五种食线虫真菌（NF），它们攻击和杀死 EPNs。在两个不同的农业系统（柑橘和蓝莓）中，我们检测到了多种线虫和真菌；然而，只有 FLBNs 的行为以与之前报道的 EPNs 相似的方式受到影响。尽管检测到了，但 NF 的丰度并没有因地下 HIPV 的存在而受到统计学上的影响。我们提供了第一个证据，表明地下 HIPV 的行为与地上 HIPV 非常相似，不仅吸引了寄生蜂，还吸引了超寄生蜂和其他食物网成员。
