Acute toxicity of the plant volatile indole depends on herbivore specialization
Acute toxicity of the plant volatile indole depends on herbivore specialization
复制标题
DOI：
10.1007/s10340-020-01218-6
复制
发表时间：
2020-06-01
影响因子：
4.8
通讯作者：
Frost, Christopher J.
中科院分区：
文献类型：
--
作者：
Maurya, Abhinav K.;Patel, Rakhi C.;Frost, Christopher J.
食草动物诱导的植物挥发物（HIPVs）作为抗菌剂和食草动物驱避剂对植物有直接的益处，但其作为食草动物直接毒素的潜力尚不清楚。在这里，我们从三个不同的生化途径测定了六种常见的HIPVs的杀幼虫活性，并验证了HIPVs的杀幼虫活性与害虫的寄主专化性有关的假设。我们首先评估了β-香芹烯、芳樟醇、乙酸顺-3-己烯酯、顺-3-己烯醇、e-2-己烯醛和吲哚对甜菜夜蛾（Spodoptera exigua）的毒性，发现吲哚与其他挥发物相比，当掺入饲料中时毒性高7倍。然后，我们测试了杀幼虫活性的吲哚对六种常见的，破坏性的害虫毛虫与不同的主机范围。与我们的假设相一致，吲哚毒性与毛虫宿主范围：吲哚毒性是7倍更专业的昆虫物种相对于通才昆虫物种。也就是说，吲哚的LC 50与其他报道的抗草食动物剂相当，甚至对通才毛虫也是如此。然而，顶空中的吲哚对任何测试的毛毛虫物种都没有杀幼虫或杀卵活性。这些结果支持了一个关键的生态学规则的主机专业化和化学解毒之间的权衡，也表明，吲哚，特别是直接有毒的食草动物，因此可能有用的综合害虫管理策略。
Herbivore-induced plant volatiles (HIPVs) provide direct benefits to plants as antimicrobials and herbivore repellents, but their potential as direct toxins to herbivores is unclear. Here, we assayed the larvicidal activity of six common HIPVs from three different biochemical pathways and tested the hypothesis that the larvicidal activity of HIPVs is related to the host specialization of the insect pest. We first assessed beta-caryophyllene, linalool, z-3-hexenyl acetate, z-3-hexenol, e-2-hexenal, and indole against the beet armyworm (Spodoptera exigua) and found that indole was sevenfold more toxic compared to the other volatiles when incorporated into the diet. Then, we tested the larvicidal activity of indole against six common, destructive pest caterpillars with varying host ranges. Consistent with our hypothesis, indole toxicity varied with caterpillar host range: indole toxicity was sevenfold higher in more specialized insect species relative to generalist insect species. That said, the LC50 of indole was comparable to other reported anti-herbivore agents even against the generalist caterpillars. Yet, indole in headspace had neither larvicidal nor ovicidal activity on any caterpillar species tested. These results support a key ecological precept of a trade-off between host specialization and chemical detoxification and also indicate that indole in particular is directly toxic to herbivores and therefore potentially useful in integrated pest management strategies.