Compatible and incompatible pathogen-plant interactions differentially affect plant volatile emissions and the attraction of parasitoid wasps

The effects of multiple insect attacks on herbivore-induced plant volatiles and carnivorous arthropods are increasingly studied. Phytopathogens also represent an important threat to plants, and plant defense strategies against pathogens and insects are strongly interconnected, yet the potential impact of pathogens on insect-induced volatiles has been largely overlooked, and degree of pathogenicity rarely considered. We investigated how pathogen challenge, with virulent and avirulent strains of Xanthomonas campestris either alone or with simultaneous Pieris brassicae caterpillar herbivory, affected the volatile emissions of Brassica nigra plants. The impact of these volatiles on the foraging behavior of Cotesia glomerata parasitoids was then assessed. Pathogens themselves induced volatiles that were highly attractive to parasitoids, and enhanced the attractiveness of host-infested plant volatiles. Chemical analyses revealed that virulent and avirulent strains differentially induced plant...

多重昆虫取食对植食性昆虫诱导的植物挥发物及肉食性节肢动物的影响，正日益受到学界关注。植物病原物同样对植物构成重要威胁，且植物针对病原物与昆虫的防御策略存在紧密关联，但病原物对昆虫诱导挥发物的潜在影响长期以来被大幅忽视，致病力强弱也极少被纳入考量范畴。本研究以黑芥（Brassica nigra）植株为材料，探究了单独接种强毒株与无毒株的野油菜黄单胞菌（Xanthomonas campestris），或是同时接种该病原物并施加菜粉蝶（Pieris brassicae）幼虫取食胁迫，对其挥发物释放的影响；随后评估了这些挥发物对菜蛾盘绒茧蜂（Cotesia glomerata）寄生蜂觅食行为的作用。实验结果表明，病原物自身诱导产生的挥发物对寄生蜂具有极高吸引力，且能增强寄主植株被取食后挥发物的诱集效果。化学分析显示，强毒株与无毒株可差异性诱导植物……