ANSES, INRAE, Ecole Nationale Vétérinaire d'Alfort, UMR BIPAR, Laboratoire de Santé Animale, Maisons-Alfort, France.
INRAE, UR 0045 Laboratoire de Recherches Sur Le Développement de L'Elevage (SELMET-LRDE), Corte, France.
Mol Ecol. 2023 Aug;32(16):4660-4676. doi: 10.1111/mec.17058. Epub 2023 Jun 27.
Most tick-borne pathogens (TBPs) are secondarily acquired by ticks during feeding on infected hosts, which imposes 'priority effect' constraints, as arrival order influences the establishment of new species in a microbial community. Here we tested whether once acquired, TBPs contribute to bacterial microbiota functioning by increasing community stability. For this, we used Hyalomma marginatum and Rhipicephalus bursa ticks collected from cattle in different locations of Corsica and combined 16S rRNA amplicon sequencing and co-occurrence network analysis, with high-throughput pathogen detection, and in silico removal of nodes to test for impact of rickettsial pathogens on network properties. Despite its low centrality, Rickettsia showed preferential connections in the networks, notably with a keystone taxon in H. marginatum, suggesting facilitation of Rickettsia colonisation by the keystone taxon. In addition, conserved patterns of community assembly in both tick species were affected by Rickettsia removal, suggesting that privileged connections of Rickettsia in the networks make this taxon a driver of community assembly. However, Rickettsia removal had minor impact on the conserved 'core bacterial microbiota' of H. marginatum and R. bursa. Interestingly, networks of the two tick species with Rickettsia have similar node centrality distribution, a property that is lost after Rickettsia removal, suggesting that this taxon drives specific hierarchical interactions between bacterial microbes in the microbiota. The study indicates that tick-borne Rickettsia play a significant role in the tick bacterial microbiota, despite their low centrality. These bacteria are influential and contribute to the conservation of the 'core bacterial microbiota' while also promoting community stability.
大多数蜱传病原体 (TBPs) 是蜱在感染宿主身上吸血时继发性获得的，这就产生了“优先效应”的限制，因为到达的顺序会影响微生物群落中新物种的建立。在这里，我们测试了一旦获得，TBPs 是否通过增加群落稳定性来促进细菌微生物群落的功能。为此，我们使用了从科西嘉不同地点的牛身上收集的边缘硬蜱和肩突硬蜱，并结合了 16S rRNA 扩增子测序和共生网络分析，以及高通量病原体检测和计算去除节点，以测试立克次体病原体对网络特性的影响。尽管其中心性较低，但立克次体在网络中表现出优先连接，特别是在边缘硬蜱中与一个关键分类群连接，这表明关键分类群有利于立克次体的定植。此外，两种蜱类的群落组装模式受到立克次体去除的影响，这表明网络中立克次体的特权连接使该分类群成为群落组装的驱动因素。然而，立克次体的去除对立克次体和肩突硬蜱的保守“核心细菌微生物群”的影响较小。有趣的是，具有立克次体的两种蜱类的网络具有相似的节点中心性分布，而立克次体去除后这种特性就会丢失，这表明该分类群驱动了微生物群中细菌微生物之间的特定层次相互作用。该研究表明，尽管蜱传立克次体的中心性较低，但它们在蜱的细菌微生物群中起着重要作用。这些细菌具有影响力，并有助于“核心细菌微生物群”的保护，同时促进群落稳定性。
