Estrada-Peña Agustín, Cabezas-Cruz Alejandro, Obregón Dasiel
Faculty of Veterinary Medicine, University of Zaragoza, 50013 Zaragoza, Spain.
UMR BIPAR, INRAE, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 94700 Maisons-Alfort, France.
Microorganisms. 2020 Nov 20;8(11):1829. doi: 10.3390/microorganisms8111829.
The taxonomic composition and diversity of tick midgut microbiota have been extensively studied in different species of the genera , , , , , , and , while the functional significance of bacterial diversity has been proportionally less explored. In this study, we used previously published 16S amplicon sequence data sets from three cohorts, two of uninfected nymphs, and one of larvae experimentally infected with , to test the functional redundancy of the tick microbiome. We predicted the metabolic profiling of each sample using the state-of-the-art metagenomics tool PICRUSt2. The results showed that the microbiomes of all samples share only 80 taxa (24.6%, total 324), while out of the 342 metabolic pathways predicted, 82.7%, were shared by all the ticks. -infected larvae lack 15.4% of pathways found in the microbiome of uninfected nymphs. Taxa contribution analysis showed that the functional microbiome of uninfected ticks was highly redundant, with, in some cases, up to 198 bacterial taxa contributing to a single pathway. However, -infected larvae had a smaller redundancy with 6.7% of pathways provided by more than 100 genera, while 15.7-19.2% of pathways were provided by more than 100 genera in the two cohorts of uninfected ticks. In addition, we compared the functional profiles of three microbial communities from each data set, identified through a network-based approach, and we observed functional similarity between them. Based on the functional redundancy and functional similarity of the microbiome of ticks in different developmental stages and infection status, we concluded that the tick gut microbiota is a self-regulating community of very diverse bacteria contributing to a defined set of metabolic pathways and functions with yet unexplored relevance for tick fitness and/or bacterial community stability. We propose a change of focus in which the tick microbiome must be analyzed in all dimensions, highlighting their functional traits, instead of the conventional taxonomic profiling.
蜱虫中肠微生物群的分类组成和多样性已在璃眼蜱属、硬蜱属、血蜱属、扇头蜱属、牛蜱属、革蜱属和蜱属的不同物种中得到广泛研究，而细菌多样性的功能意义却较少被探究。在本研究中，我们使用了先前发表的来自三个队列的16S扩增子序列数据集，其中两个队列是未感染的若虫，另一个队列是经实验感染了[病原体名称未给出]的幼虫，以测试蜱虫微生物组的功能冗余性。我们使用最先进的宏基因组学工具PICRUSt2预测了每个样本的代谢谱。结果表明，所有[样本数量未给出]个样本的微生物组仅共享80个分类单元（占总数324个的24.6%），而在预测的342条代谢途径中，82.7%的途径为所有蜱虫所共有。感染[病原体名称未给出]的幼虫缺少未感染若虫微生物组中发现的15.4%的途径。分类单元贡献分析表明，未感染蜱虫的功能性微生物组具有高度冗余性，在某些情况下，多达198个细菌分类单元可促成单一途径。然而，感染[病原体名称未给出]的幼虫冗余性较小，超过100个属提供了6.7%的途径，而在两个未感染蜱虫队列中，超过100个属提供了15.7 - 19.2%的途径。此外，我们比较了通过基于网络的方法从每个数据集中识别出的三个微生物群落的功能谱，并且观察到它们之间的功能相似性。基于不同发育阶段和感染状态下蜱虫微生物组的功能冗余性和功能相似性，我们得出结论，蜱虫肠道微生物群是一个由非常多样的细菌组成的自我调节群落，它们促成了一组特定的代谢途径和功能，而这些途径和功能与蜱虫健康和/或细菌群落稳定性的相关性尚未得到探索。我们建议改变关注点，即必须从所有维度分析蜱虫微生物组，突出其功能特征，而不是传统的分类分析。
