Powdery mildew suppresses herbivore-induced plant volatiles and interferes with parasitoid attraction in Brassica rapa
Powdery mildew suppresses herbivore-induced plant volatiles and interferes with parasitoid attraction in Brassica rapa
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DOI：
10.1111/pce.12752
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发表时间：
2016-09-01
影响因子：
7.3
通讯作者：
Turlings, Ted C. J.
中科院分区：
文献类型：
--
作者：
Desurmont, Gaylord A.;Xu, Hao;Turlings, Ted C. J.
不同拮抗剂在植物上的共同作用可以极大地影响信息化学物质，并对更高营养水平产生生态后果。在这里，我们研究了植物病原体十字花科白粉病（Erysiphe cruciferarum）在油菜上的存在如何影响(1)植物挥发性物质对专业食草动物青花甘蓝（Pieris brassicae）损害的反应；(2)寄生黄蜂的吸引力；(3)芸苔科和球孢小蜂的表现。草食对健康植株和霉变植株的挥发物含量均有显著的诱导作用，但霉变植株的挥发物含量比健康植株低41%。拟寄生物强烈偏爱被皮粉虫侵染的植物而不是双侵染（皮粉虫+霉病）的植物，并且偏爱双侵染的植物而不是只被霉病侵染的植物。白粉病对芸苔科植物的产茧性能没有影响，但在被白粉病侵染的植株上，被寄生毛虫的茧质量降低。因此，避免被霉菌侵染的植物可能是C. glomerata寄生蜂的适应性，而P. brassicae毛虫在自然界中可能较少寄生在被霉菌侵染的植物上。从害虫管理的角度来看，多种植物拮抗剂的同时存在会影响特定天敌的效率，从而可能对害虫种群的调节产生负面影响。不同拮抗剂在植物上的共存在群落水平上会产生多营养后果。本研究表明，十字花科白粉病（Erysiphe cruciferarum）侵染芸苔（Brassica rapa）后，可显著减少植物因受食草昆虫青花蜂（Pieris brassicae）伤害而释放的挥发物，并降低植物对芸苔科主要天敌（Cotesia glomerata）的吸引力。草食性能不受白粉病的影响，但寄生性性能受到负面影响（茧质量下降）。从害虫管理的角度来看，芸苔属植物上白粉病的存在可能会影响天敌的觅食效率，从而可能对害虫种群的调控产生负面影响。
The co-occurrence of different antagonists on a plant can greatly affect infochemicals with ecological consequences for higher trophic levels. Here we investigated how the presence of a plant pathogen, the powdery mildew Erysiphe cruciferarum, on Brassica rapa affects (1) plant volatiles emitted in response to damage by a specialist herbivore, Pieris brassicae; (2) the attraction of the parasitic wasp Cotesia glomerata and (3) the performance of P. brassicae and C. glomerata. Plant volatiles were significantly induced by herbivory in both healthy and mildew-infected plants, but were quantitatively 41% lower for mildew-infected plants compared to healthy plants. Parasitoids strongly preferred Pieris-infested plants to dually-infested (Pieris+mildew) plants, and preferred dually infested plants over only mildew-infected plants. The performance of P. brassicae was unaffected by powdery mildew, but C. glomerata cocoon mass was reduced when parasitized caterpillars developed on mildew-infected plants. Thus, avoidance of mildew-infested plants may be adaptive for C. glomerata parasitoids, whereas P. brassicae caterpillars may suffer less parasitism on mildew-infected plants in nature. From a pest management standpoint, the concurrent presence of multiple plant antagonists can affect the efficiency of specific natural enemies, which may in turn have a negative impact on the regulation of pest populations.The co-occurrence of different antagonists on a plant can have multitrophic consequences at the community level. Here we show that infection by a fungal pathogen, the powdery mildew Erysiphe cruciferarum, on Brassica rapa strongly reduces plant volatiles emitted in response to damage by the insect herbivore Pieris brassicae, and reduces plant attractiveness to the main natural enemy of P. brassicae, the parasitic wasp Cotesia glomerata. Herbivore performance was unaffected by the presence of powdery mildew, but parasitoid performance was negatively affected (decreased cocoon mass). From a pest management standpoint, the presence of powdery mildew on Brassica plants may affect the foraging efficiency of natural enemies, which may in turn have a negative impact on the regulation of pest populations.