A facultative endosymbiont in aphids can provide diverse ecological benefits.
A facultative endosymbiont in aphids can provide diverse ecological benefits.
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DOI：
10.1111/jeb.12705
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发表时间：
2015-10
影响因子：
2.1
通讯作者：
Ferrari J
中科院分区：
文献类型：
--
作者：
Heyworth ER;Ferrari J
昆虫的生态重要特征常常受到兼性细菌内共生体的影响。这在豌豆蚜 Acyrthosiphon pisum 中得到了最好的研究，它经常被八种兼性共生体中的一种或多种感染。许多共生物种已被证明可以提供一种生态效益，但我们对单一菌株可以产生的影响范围知之甚少。在这里，我们描述了最近发现的 X 型（肠杆菌科）细菌的三种菌株所赋予的表型，每种菌株都具有原始的蚜虫基因型，也携带螺原体共生体。所有比较都是在同时感染螺原体和 X 型的蚜虫与仅携带螺原体的相同基因型的蚜虫之间进行的。我们发现，在所有情况下，X型感染都可以保护蚜虫免受致命真菌病原体潘多拉新蚜虫的侵害，并且在两种情况下，对寄生蜂蚜虫的抵抗力也有所增加。 X型还可以影响蚜虫的应激反应——X型的存在会增加蚜虫在热应激后的繁殖。三种 X 型菌株中的两种能够提供所有这些益处。在良性条件下，当携带 X 型蚜虫时，其繁殖力往往会降低，而 X 型蚜虫的繁殖力可能会在田间种群中保持中间频率。这些发现强调，兼性内共生体的单一菌株有可能为其蚜虫宿主提供多种益处。
Ecologically important traits of insects are often affected by facultative bacterial endosymbionts. This is best studied in the pea aphid Acyrthosiphon pisum, which is frequently infected by one or more of eight facultative symbiont species. Many of these symbiont species have been shown to provide one ecological benefit, but we have little understanding of the range of effects that a single strain can have. Here, we describe the phenotypes conferred by three strains of the recently discovered bacterium known as X‐type (Enterobacteriaceae), each in their original aphid genotype which also carries a Spiroplasma symbiont. All comparisons are made between aphids that are coinfected with Spiroplasma and X‐type and aphids of the same genotype that harbour only Spiroplasma. We show that in all cases, infection with X‐type protects aphids from the lethal fungal pathogen Pandora neoaphidis, and in two cases, resistance to the parasitoid Aphidius ervi also increases. X‐type can additionally affect aphid stress responses – the presence of X‐type increased reproduction after the aphids were heat‐stressed. Two of the three strains of X‐type are able to provide all of these benefits. Under benign conditions, the aphids tended to suffer from reduced fecundity when harbouring X‐type, a mechanism that might maintain intermediate frequencies in field populations. These findings highlight that a single strain of a facultative endosymbiont has the potential to provide diverse benefits to its aphid host.