Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Zürich, Switzerland.
Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), 12587 Berlin, Germany.
FEMS Microbiol Ecol. 2022 Sep 19;98(10). doi: 10.1093/femsec/fiac097.
Host-associated bacterial communities play an important role in host fitness and resistance to diseases. Yet, few studies have investigated tripartite interaction between a host, parasite and host-associated bacterial communities in natural settings. Here, we use 16S rRNA gene amplicon sequencing to compare gut- and body- bacterial communities of wild water fleas belonging to the Daphnia longispina complex, between uninfected hosts and those infected with the common and virulent eukaryotic gut parasite Caullerya mesnili (Family: Ichthyosporea). We report community-level changes in host-associated bacteria with the presence of the parasite infection; namely decreased alpha diversity and increased beta diversity at the site of infection, i.e. host gut (but not host body). We also report decreased abundance of bacterial taxa proposed elsewhere to be beneficial for the host, and an appearance of taxa specifically associated with infected hosts. Our study highlights the host-microbiota-infection link in a natural system and raises questions about the role of host-associated microbiota in natural disease epidemics as well as the functional roles of bacteria specifically associated with infected hosts.
宿主相关细菌群落对宿主的适应能力和疾病抵抗力起着重要作用。然而，在自然环境中，很少有研究调查宿主、寄生虫和宿主相关细菌群落之间的三方相互作用。在这里，我们使用 16S rRNA 基因扩增子测序，比较了属于长额溞复合种的野生水蚤的肠道和体躯细菌群落，包括未感染的宿主和感染了常见且具有毒性的真核肠道寄生虫 Caullerya mesnili（科：Ichthyosporea）的宿主。我们报告了宿主相关细菌群落随寄生虫感染而发生的变化；即在感染部位（即宿主肠道），alpha 多样性降低，beta 多样性增加，但宿主体躯无变化。我们还报告了其他地方提出的对宿主有益的细菌分类群的丰度降低，以及专门与感染宿主相关的分类群的出现。我们的研究强调了自然系统中宿主-微生物群-感染的联系，并提出了关于宿主相关微生物群在自然疾病流行中的作用以及与感染宿主相关的细菌的特定功能作用的问题。
