Within‐host interactions shape virulence‐related traits of trematode genotypes
Within‐host interactions shape virulence‐related traits of trematode genotypes
复制标题
宿主内相互作用塑造吸虫基因型的毒力相关特征
DOI：
10.1111/jeb.13438
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发表时间：
2019
影响因子：
2.1
通讯作者：
A. Karvonen
中科院分区：
文献类型：
--
作者：
I. Klemme;A. Karvonen
共感染寄生虫之间的宿主内相互作用可以显著影响关键寄生虫特征的进化，如毒力(感染的致病性)。交互作用的类型有望预测选择的方向，拮抗交互作用有利于毒力较强的基因类型，而协同作用有利于毒力较低的基因类型。最近，有人提出，毒力可以进一步受到共同感染伙伴的遗传同一性(G×G相互作用)的影响，这使得对疾病动态的预测变得复杂。在这里，我们使用一个包括鱼宿主和吸虫寄生虫的自然宿主-寄生虫系统来研究G×G相互作用对感染毒力的影响。我们将虹鳟鱼(Oncorhynchus MykISS)暴露于眼吸虫假性双口线虫的单一基因或两种基因的混合，并估计了寄生虫的传染性(与感染的致病性线性相关，测量为眼白内障覆盖率)和相对白内障覆盖率(控制传染性)。我们发现，这两个性状都与复杂的G×G交互作用有关，包括从单一感染到混合感染的增加和减少，这取决于基因组合。特别是，在单一感染中，两种基因类型的平均传染性和相对白内障覆盖率较低的组合受益于联合感染，而表现较好的基因类型的模式相反。总而言之，我们的结果表明，在单独感染和联合感染之间，感染结果有很大的不同，并且与联合感染寄生虫的遗传同一性有很大差异。这会导致寄生虫适合度的变化，从而影响宿主-寄生虫相互作用的进化动力学。
Within‐host interactions between co‐infecting parasites can significantly influence the evolution of key parasite traits, such as virulence (pathogenicity of infection). The type of interaction is expected to predict the direction of selection, with antagonistic interactions favouring more virulent genotypes and synergistic interactions less virulent genotypes. Recently, it has been suggested that virulence can further be affected by the genetic identity of co‐infecting partners (G × G interactions), complicating predictions on disease dynamics. Here, we used a natural host–parasite system including a fish host and a trematode parasite to study the effects of G × G interactions on infection virulence. We exposed rainbow trout (Oncorhynchus mykiss) either to single genotypes or to mixtures of two genotypes of the eye fluke Diplostomum pseudospathaceum and estimated parasite infectivity (linearly related to pathogenicity of infection, measured as coverage of eye cataracts) and relative cataract coverage (controlled for infectivity). We found that both traits were associated with complex G × G interactions, including both increases and decreases from single infection to co‐infection, depending on the genotype combination. In particular, combinations where both genotypes had low average infectivity and relative cataract coverage in single infections benefited from co‐infection, while the pattern was opposite for genotypes with higher performance. Together, our results show that infection outcomes vary considerably between single and co‐infections and with the genetic identity of the co‐infecting parasites. This can result in variation in parasite fitness and consequently impact evolutionary dynamics of host–parasite interactions.