Fungal endophyte negative effects on herbivory are enhanced on intact plants and maintained in a subsequent generation
Fungal endophyte negative effects on herbivory are enhanced on intact plants and maintained in a subsequent generation
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DOI：
10.1111/j.1365-2311.2009.01152.x
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发表时间：
2010-02-01
影响因子：
2.2
通讯作者：
Vidal, Stefan
中科院分区：
文献类型：
--
作者：
Jaber, Lara R.;Vidal, Stefan
2.真正有效地防御食草动物可能需要植物的正常功能，因为切除的叶子与仍然附着在植物上的叶子相比可能抵抗力较低。然而，大多数研究内生菌在赋予宿主对食草动物的抗性方面的可能作用都是在植物部分而不是完整植物上进行的。采用根内生真菌（Acremonium strictum）-蚕豆（Vicia faba）-通性食草动物（Helicoverpa armigera）模型，研究内生真菌对食草动物的影响是否取决于研究中使用的实验环境，以及它们是否会转化为下一代食草动物.枝顶孢对H.棉铃虫第一代幼虫在接种的完整植株上自由取食比接种植株的叶盘取食更明显。此外，这些影响被带入H。第二代棉铃虫以人工饲料饲养.不能从蚕豆叶中重新分离到枝顶孢霉;因此可以排除内生菌与昆虫之间的直接接触。或者，挥发性物质的损失或抑制作用较强的化合物在原位可能会导致幼虫取食和叶盘上的表现与完整植物相比发生变化，无论感染状态如何。我们认为H.棉铃虫在两代之间的传播是通过内生菌引发的植物质量降低间接引起的。
2. Truly effective defences against herbivores may require normal functioning of the plant, as excised leaves may be less resistant as compared with those still attached to the plant. Yet, most studies investigating possible effects of endophytes in conferring host resistance to herbivores have been conducted with plant parts rather than intact plants.3. Using the root endophytic fungus (Acremonium strictum)-broad bean (Vicia faba)-generalist herbivore (Helicoverpa armigera) model, we conducted experiments to examine whether endophyte effects on herbivory would depend on the experimental setting used in the investigation and whether they would translate into a subsequent generation of the herbivore.4. Acremonium strictum negative effects on the fitness of H. armigera first generation were more evident when the larvae foraged freely on inoculated intact whole plants than when offered leaf discs of inoculated plants. Furthermore, these effects were carried over into H. armigera second generation reared on an artificial diet.5. Acremonium strictum could not be re-isolated from V. faba leaves; hence direct contact between the endophyte and the insect could be excluded. Alternatively, loss of volatiles or inhibitory effects of compounds that were stronger in situ might have caused changes in larval feeding and performance on leaf discs as compared with intact plants, regardless of infection status.6. We suggest that the reduction in fitness parameters of H. armigera across two generations is caused indirectly via an endophyte-triggered reduction in plant quality.