Defense of pyrethrum flowers: repelling herbivores and recruiting carnivores by producing aphid alarm pheromone
Defense of pyrethrum flowers: repelling herbivores and recruiting carnivores by producing aphid alarm pheromone
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除虫菊花的防御：通过产生蚜虫警报信息素来驱逐食草动物并招募食肉动物
DOI：
10.1111/nph.15869
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发表时间：
2019-08-01
期刊：
影响因子：
9.4
通讯作者：
Wang，Caiyun
中科院分区：
文献类型：
--
作者：
Li，Jinjin;Hu，Hao;Wang，Caiyun
(E)- β-法尼烯（EβF）是大多数蚜虫害虫报警信息素的主要成分。蚜虫的天敌利用EβF来定位猎物。一些植物物种释放EβF，可能作为对蚜虫的防御，但缺乏现场示范。在这里，我们介绍了花防御的现场和实验室研究，表明瓢虫主要被吸引到年轻的阶段-2除虫菊花，释放最高和最纯净的EβF水平。S2除虫菊花释放的EβF对蚜虫有明显的驱避作用。虽然桃蚜在实验室中可以适应除虫菊植物，但在田间没有记录到蚜虫。除虫菊的（E）-β-法呢烯合酶（EbFS）基因在蚜虫偏好的花托和花梗的维管系统周围的内皮层组织中强烈表达，导致充满EβF的细长细胞。在定居期间探测这些组织的蚜虫遇到并摄取植物EβF，如蜜露中的释放所证明的。蜜露中的EβF浓度诱导蚜虫报警反应，表明这种防御的额外层。总的来说，我们的数据阐明了除虫菊花中的防御模拟：发育调节和组织特异性的EβF积累和释放既防止蚜虫的攻击，又招募蚜虫捕食者作为保镖。
(E)‐β‐Farnesene (EβF) is the predominant constituent of the alarm pheromone of most aphid pest species. Moreover, natural enemies of aphids use EβF to locate their aphid prey. Some plant species emit EβF, potentially as a defense against aphids, but field demonstrations are lacking.Here, we present field and laboratory studies of flower defense showing that ladybird beetles are predominantly attracted to young stage‐2 pyrethrum flowers that emitted the highest and purest levels of EβF. By contrast, aphids were repelled by EβF emitted by S2 pyrethrum flowers. Although peach aphids can adapt to pyrethrum plants in the laboratory, aphids were not recorded in the field.Pyrethrum's(E)‐β‐farnesene synthase(EbFS) gene is strongly expressed in inner cortex tissue surrounding the vascular system of the aphid‐preferred flower receptacle and peduncle, leading to elongated cells filled with EβF. Aphids that probe these tissues during settlement encounter and ingest plant EβF, as evidenced by the release in honeydew. These EβF concentrations in honeydew induce aphid alarm responses, suggesting an extra layer of this defense.Collectively, our data elucidate a defensive mimicry in pyrethrum flowers: the developmentally regulated and tissue‐specific EβF accumulation and emission both prevents attack by aphids and recruits aphid predators as bodyguards.