Water Quality and Microbial Diversity, Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, Girona, Spain.
Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Girona, Spain.
PLoS One. 2020 Apr 8;15(4):e0231238. doi: 10.1371/journal.pone.0231238. eCollection 2020.
Members of the phylum Bathyarchaeota and the class Thermoplasmata are widespread in marine and freshwater sediments where they have been recognized as key players in the carbon cycle. Here, we tested the responsiveness of archaeal communities on settled plant debris and sediment from a karstic lake to different organic carbon amendments (amino acids, plant-derived carbohydrates, and aromatics) using a lab-scale microcosm. Changes in the composition and abundance of sediment and biofilm archaeal communities in both DNA and RNA fractions were assessed by 16S rRNA gene amplicon sequencing and qPCR, respectively, after 7 and 30 days of incubation. Archaeal communities showed compositional changes in terms of alpha and beta diversity in relation to the type of carbon source (amino acids vs. plant-derived compounds), the nucleic acid fraction (DNA vs. RNA), and the incubation time (7 vs. 30 days). Distinct groups within the Bathyarchaeota (Bathy-15 and Bathy-6) and the Thermoplasmata (MBG-D) differently reacted to carbon supplements as deduced from the analysis of RNA libraries. Whereas Bathyarchaeota in biofilms showed a long-term positive response to humic acids, their counterparts in the sediment were mainly stimulated by the addition of tryptophan, suggesting the presence of different subpopulations in both habitats. Overall, our work presents an in vitro assessment of the versatility of archaea inhabiting freshwater sediments towards organic carbon and introduces settled leaf litter as a new habitat for the Bathyarchaeota and the Thermoplasmata.
门 Bathyarchaeota 和纲 Thermoplasmata 的成员广泛存在于海洋和淡水沉积物中，它们被认为是碳循环中的关键参与者。在这里，我们使用实验室规模的微宇宙测试了定殖植物碎片和喀斯特湖沉积物中古菌群落对不同有机碳添加剂（氨基酸、植物衍生碳水化合物和芳烃）的反应。通过 16S rRNA 基因扩增子测序和 qPCR，分别评估了 DNA 和 RNA 分数中沉积物和生物膜古菌群落的组成和丰度的变化，在孵育 7 和 30 天后。古菌群落的组成和多样性发生了变化，这与碳源的类型（氨基酸与植物衍生化合物）、核酸分数（DNA 与 RNA）和孵育时间（7 天与 30 天）有关。从 RNA 文库分析中可以看出，Bathyarchaeota 中的不同群体（Bathy-15 和 Bathy-6）和 Thermoplasmata（MBG-D）对碳补充剂有不同的反应。虽然生物膜中的 Bathyarchaeota 对腐殖酸表现出长期的正反应，但它们在沉积物中的对应物主要受到色氨酸添加的刺激，这表明在这两个栖息地中存在不同的亚群。总的来说，我们的工作对栖息在淡水沉积物中的古菌对有机碳的多功能性进行了体外评估，并引入了定殖的落叶作为 Bathyarchaeota 和 Thermoplasmata 的新栖息地。
