O'Keeffe Kayleigh R, Wheeler Brandon T, Mitchell Charles E
Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Department of Biology, University of Pennsylvania, Philadelphia, PA, United States.
Front Microbiol. 2022 Apr 21;13:824211. doi: 10.3389/fmicb.2022.824211. eCollection 2022.
The interactions among host-associated microbes and parasites can have clear consequences for disease susceptibility and progression within host individuals. Yet, empirical evidence for how these interactions impact parasite transmission between host individuals remains scarce. We address this scarcity by using a field mesocosm experiment to investigate the interaction between a systemic fungal endophyte, , and a fungal parasite, , in leaves of a grass host, tall fescue (). Specifically, we investigated how this interaction impacted transmission of the parasite under field conditions in replicated experimental host populations. -inoculated populations tended to have greater disease prevalence over time, though this difference had weak statistical support. More clearly, -inoculated populations experienced higher peak parasite prevalences than -free populations. conferred a benefit in growth; -inoculated populations had greater aboveground biomass than -free populations. Using biomass as a proxy, host density was correlated with peak parasite prevalence, but still increased peak parasite prevalence after controlling for the effect of biomass. Together, these results suggest that within-host microbial interactions can impact disease at the population level. Further, while is clearly a mutualist of tall fescue, it may not be a defensive mutualist in relation to .
宿主相关微生物与寄生虫之间的相互作用会对宿主个体内疾病的易感性和进展产生明显影响。然而，关于这些相互作用如何影响寄生虫在宿主个体之间传播的实证证据仍然很少。我们通过一项野外中宇宙实验来解决这一证据不足的问题，该实验旨在研究一种系统性真菌内生菌与一种真菌寄生虫在禾本科宿主高羊茅叶片中的相互作用。具体而言，我们研究了这种相互作用如何在重复的实验宿主种群的野外条件下影响寄生虫的传播。随着时间的推移，接种内生菌的种群往往具有更高的疾病患病率，尽管这一差异的统计支持较弱。更明显的是，接种内生菌的种群比未接种内生菌的种群经历了更高的寄生虫患病率峰值。内生菌在生长方面带来了益处；接种内生菌的种群地上生物量比未接种内生菌的种群更大。以生物量为指标，宿主密度与寄生虫患病率峰值相关，但在控制了生物量的影响后，内生菌仍会增加寄生虫患病率峰值。综合来看，这些结果表明宿主内微生物相互作用可在种群水平上影响疾病。此外，虽然内生菌显然是高羊茅的共生菌，但就寄生虫而言，它可能并非防御性共生菌。
