Facilitative priority effects drive parasite assembly under coinfection
Facilitative priority effects drive parasite assembly under coinfection
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DOI：
10.1038/s41559-020-01289-9
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发表时间：
2020-08-31
影响因子：
16.8
通讯作者：
Laine, Anna-Liisa
中科院分区：
文献类型：
--
作者：
Halliday, Fletcher W.;Penczykowski, Rachel M.;Laine, Anna-Liisa
宿主个体经常与不同的寄生虫组合共同感染，导致宿主内寄生虫之间复杂的相互作用。在宿主内部，当感染序列改变寄生虫之间相互作用的结果时，就会产生优先效应。然而，宿主免疫在这一过程中的作用仍然知之甚少。我们假设，宿主对第一次感染的反应可能会在寄生虫之间产生优先效应，在流行期间改变后来到达的菌株的组装。我们通过用植物豆腐病菌菌株感染前哨寄主类型的车前草来测试这一点，并测量了在实验和自然流行期间对后续感染的敏感性。在这些实验中，先前被一种菌株感染往往会增加对其他菌株的易感性，这些促进优先效应改变了寄生虫组合的结构，但这种影响取决于宿主基因、宿主种群和寄生虫基因。因此，寄主基因、空间结构和菌株间的优先效应都独立地改变了寄生虫的组装。通过对几个种群中野生宿主的感染进行精细调查和采样，我们确定了一个促进优先效应的信号，它改变了自然流行期间的寄生虫聚集。总之，这些结果提供了证据表明，早期到达的菌株在宿主内的优先效应可以驱动寄生虫聚集，这意味着在流行期间菌株多样性是如何在空间和时间上分布的。通过对常见花园和田间实验的分析，以及对野生宿主的调查，作者表明，先前被一种植物真菌寄生虫感染增加了对其他菌株感染的易感性，这种启动效应影响了寄生虫群落的聚集。
Host individuals are often coinfected with diverse parasite assemblages, resulting in complex interactions among parasites within hosts. Within hosts, priority effects occur when the infection sequence alters the outcome of interactions among parasites. Yet, the role of host immunity in this process remains poorly understood. We hypothesized that the host response to the first infection could generate priority effects among parasites, altering the assembly of later-arriving strains during epidemics. We tested this by infecting sentinel host genotypes ofPlantago lanceolatawith strains of the fungal parasitePodosphaera plantaginisand measuring susceptibility to subsequent infection during experimental and natural epidemics. In these experiments, prior infection by one strain often increased susceptibility to other strains, and these facilitative priority effects altered the structure of parasite assemblages, but this effect depended on host genotype, host population and parasite genotype. Thus, host genotype, spatial structure and priority effects among strains all independently altered parasite assembly. Using a fine-scale survey and sampling of infections on wild hosts in several populations, we then identified a signal of facilitative priority effects, which altered parasite assembly during natural epidemics. Together, these results provide evidence that within-host priority effects of early-arriving strains can drive parasite assembly, with implications for how strain diversity is spatially and temporally distributed during epidemics.By combining an analysis of common garden and field experiments, together with a survey of wild hosts, the authors show that prior infection by a plant fungal parasite increases susceptibility to infection by other strains and that this priming effect influences the assembly of the parasite community.