State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 Beijing East Road, Nanjing, 210008, China.
Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai, 519087, China.
Microb Ecol. 2023 Nov;86(4):2756-2769. doi: 10.1007/s00248-023-02280-0. Epub 2023 Aug 5.
Permafrost active layer soils are harsh environments with thaw/freeze cycles and sub-zero temperatures, harboring diverse microorganisms. However, the distribution patterns, assembly mechanism, and driving forces of soil microeukaryotes in permafrost remain largely unknown. In this study, we investigated microeukaryotes in permafrost active layer across the Qinghai-Tibet Plateau (QTP) using 18S rRNA gene sequencing. The results showed that the microbial eukaryotic communities were dominated by Nematozoa, Ciliophora, Ascomycota, Cercozoa, Arthropoda, and Basidiomycota in terms of relative abundance and operational taxonomic unit (OTU) richness. Nematozoa had the highest relative abundance, while Ciliophora had the highest OTU richness. These phyla had strong interactions between each other. Their alpha diversity and community structure were differently influenced by the factors associated to location, climate, and soil properties, particularly the soil properties. Significant but weak distance-decay relationships with different slopes were established for the communities of these dominant phyla, except for Basidiomycota. According to the null model, community assemblies of Nematozoa and Cercozoa were dominated by heterogeneous selection, Ciliophora and Ascomycota were dominated by dispersal limitation, while Arthropoda and Basidiomycota were highly dominated by non-dominant processes. The assembly mechanisms can be jointly explained by biotic interactions, organism treats, and environmental influences. Modules in the co-occurrence network of the microeukaryotes were composed by members from different taxonomic groups. These modules also had interactions and responded to different environmental factors, within which, soil properties had strong influences on these modules. The results suggested the importance of biological interactions and soil properties in structuring microbial eukaryotic communities in permafrost active layer soil across the QTP.
多年冻土活动层土壤是具有融冻循环和零下温度的恶劣环境，蕴藏着多种多样的微生物。然而，多年冻土中土壤微型真核生物的分布模式、组装机制和驱动因素在很大程度上仍不清楚。在这项研究中，我们使用 18S rRNA 基因测序研究了青藏高原多年冻土活动层的微型真核生物。结果表明，从相对丰度和操作分类单元（OTU）丰富度来看，微生物真核生物群落主要由线虫、纤毛门、子囊菌门、原生动物门、节肢动物门和担子菌门组成。线虫的相对丰度最高，而纤毛门的 OTU 丰富度最高。这些门之间存在强烈的相互作用。它们的 alpha 多样性和群落结构受到与位置、气候和土壤特性相关的因素的不同影响，特别是土壤特性。这些优势门的群落建立了显著但较弱的斜率不同的距离衰减关系，除了担子菌门。根据零模型，线虫和原生动物门的群落组装主要由异质选择主导，纤毛门和子囊菌门主要由扩散限制主导，而节肢动物门和担子菌门则主要由非主导过程主导。群落组装机制可以通过生物相互作用、生物处理和环境影响来共同解释。微型真核生物共生网络中的模块由不同分类群的成员组成。这些模块也相互作用并对不同的环境因素做出响应，其中土壤特性对这些模块有很强的影响。结果表明，生物相互作用和土壤特性在青藏高原多年冻土活动层土壤中微生物真核生物群落的结构中具有重要意义。
