ETH Zürich, Institute of Integrative Biology (IBZ), Zürich, Switzerland.
Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
Environ Microbiol Rep. 2023 Jun;15(3):188-196. doi: 10.1111/1758-2229.13142. Epub 2023 Feb 13.
The freshwater isopod Asellus aquaticus is an important decomposer of leaf detritus, and its diverse gut microbiome has been depicted as key contributors in lignocellulose degradation as of terrestrial isopods. However, it is not clear whether the individual-level microbiome profiles in the isopod digestive system across different habitats match the implied robust digestion function of the microbiome. Here, we described the bacterial diversity and abundance in the digestive system (hindgut and caeca) of multiple A. aquaticus individuals from two contrasting freshwater habitats. Individuals from a lake and a stream harboured distinct microbiomes, indicating a strong link between the host-associated microbiome and microbes inhabiting the environments. While faeces likely reflected the variations in environmental microbial communities included in the diet, the microbial communities also substantially differed in the hindgut and caeca. Microbes closely related to lignocellulose degradation are found consistently more enriched in the hindgut in each individual. Caeca often associated with taxa implicated in endosymbiotic/parasitic roles (Mycoplasmatales and Rickettsiales), highlighting a complex host-parasite-microbiome interaction. The results highlight the lability of the A. aquaticus microbiome supporting the different functions of the two digestive organs, which may confer particular advantages in freshwater environments characterized by seasonally fluctuating and spatially disparate resource availability.
淡水等足目动物水生虱是落叶碎屑的重要分解者，其多样化的肠道微生物群已被描绘为陆地等足目动物木质纤维素降解的主要贡献者。然而，目前尚不清楚不同生境中个体水平的等足目消化系统微生物组谱是否与微生物组所暗示的强大消化功能相匹配。在这里，我们描述了来自两个不同淡水生境的多个水生虱个体的消化系统（后肠和盲囊）中的细菌多样性和丰度。来自湖泊和溪流的个体具有不同的微生物组，这表明宿主相关微生物组与栖息在环境中的微生物之间存在很强的联系。虽然粪便可能反映了饮食中包含的环境微生物群落的变化，但后肠和盲囊中的微生物群落也有很大的不同。与木质纤维素降解密切相关的微生物在每个个体的后肠中都持续富集。盲囊通常与内共生/寄生作用相关的类群（支原体目和立克次体目）相关联，突出了宿主-寄生虫-微生物组相互作用的复杂性。研究结果强调了水生虱微生物组的不稳定性，支持了两个消化器官的不同功能，这可能在季节性波动和空间离散资源可用性的淡水环境中赋予其特殊优势。
