Li Yuanlong, Wei Jingyi, Yang Haijian, Zhang Delu, Hu Chunxiang
Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
University of Chinese Academy of Sciences, Beijing, China.
Front Microbiol. 2022 Apr 12;13:848908. doi: 10.3389/fmicb.2022.848908. eCollection 2022.
Archaea exhibit strong community heterogeneity with microhabitat gradients and are a non-negligible part of biocrust's microorganisms. The study on archaeal biogeography in biocrusts could provide new insights for its application in environmental restoration. However, only a few studies on assembly processes and co-occurrence patterns of the archaeal community in patchy biocrusts have been reported, especially considering the number of species pools (SPs). Here, we comprehensively collected biocrusts across 3,500 km of northern China. Different successional biocrusts from various regions contain information of local climate and microenvironments, which can shape multiple unique archaeal SPs. The archaeal community differences in the same successional stage exceeded the variations between successional stages, which was due to the fact that the heterogeneous taxa tended to exchange between unknown patches driven by drift. We also comparatively studied the driving forces of community heterogeneity across three to ten SPs, and assembly and co-occurrence patterns were systematically analyzed. The results revealed that the impact of spatial factors on biogeographic patterns was greater than that of environmental and successional factors and that impact decreased with the number of SPs considered. Meanwhile, community heterogeneity at the phylogenetic facet was more sensitive to these driving factors than the taxonomic facet. Subgroups 1 (SG1) and 2 (SG2) of the archaeal communities in biocrusts were dominated by Nitrososphaeraceae and Haloarchaea, respectively. The former distribution pattern was associated with non-salinity-related variables and primarily assembled by drift, whereas the latter was associated with salinity-related variables and primarily assembled by homogeneous selection. Finally, network analysis indicated that the SG1 network had a higher proportion of competition and key taxa than the SG2 network, but the network of SG2 was more complex. Our study suggested that the development of the archaeal community was not consistent with biocrusts succession. The dominant taxa may determine the patterns of community biogeography, assembly, and co-occurrence.
古菌在微生境梯度上表现出强烈的群落异质性，是生物结皮微生物中不可忽视的一部分。生物结皮中古菌生物地理学的研究可为其在环境恢复中的应用提供新的见解。然而，关于斑块状生物结皮中古菌群落的组装过程和共现模式的研究报道较少，尤其是考虑到物种库（SPs）的数量。在此，我们全面收集了中国北方3500公里范围内的生物结皮。来自不同地区的不同演替阶段的生物结皮包含当地气候和微环境的信息，这些信息可以塑造多个独特的古菌物种库。同一演替阶段的古菌群落差异超过了演替阶段之间的差异，这是由于异质类群倾向于在由漂移驱动的未知斑块之间交换。我们还比较研究了三到十个物种库中群落异质性的驱动力，并系统分析了组装和共现模式。结果表明，空间因素对生物地理模式的影响大于环境和演替因素，且随着所考虑的物种库数量增加，这种影响会减小。同时，系统发育层面的群落异质性比分类层面更敏感于这些驱动因素。生物结皮中古菌群落的亚组1（SG1）和亚组2（SG2）分别以硝化球菌科和嗜盐古菌为主。前者的分布模式与非盐度相关变量有关，主要通过漂移组装，而后者与盐度相关变量有关，主要通过同质选择组装。最后，网络分析表明，SG1网络比SG2网络具有更高比例的竞争和关键类群，但SG2网络更复杂。我们的研究表明，古菌群落的发展与生物结皮的演替不一致。优势类群可能决定群落生物地理学模式、组装和共现。
