Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
University of Chinese Academy of Sciences, Beijing, China.
NPJ Biofilms Microbiomes. 2021 Feb 5;7(1):15. doi: 10.1038/s41522-021-00188-6.
Biocrusts play critical eco-functions in many drylands, however it is challenging to explore their community assembly, particularly within patched successional types and across climate zones. Here, different successional biocrusts (alga, lichen, and moss-dominated biocrusts) were collected across the northern China, and assembly of biocrust microbial communities was investigated by high-throughput sequencing combined with measurements of soil properties and microclimate environments. Bacterial and eukaryotic communities showed that the maximum and minimum community variation occurred across longitude and latitude, respectively. In the regions where all three stages of biocrusts were involved, the highest community difference existed between successional stages, and decreased with distance. The community assembly was generally driven by dispersal limitation, although neutral processes have controlled the eukaryotic community assembly in hyperarid areas. Along the succession, bacterial community had no obvious patterns, but eukaryotic community showed increasing homogeneity, with increased species sorting and decreased dispersal limitation for community assembly. Compared to early successional biocrusts, there were higher microbial mutual exclusions and more complex networks at later stages, with distinct topological features. Correlation analysis further indicated that the balance between deterministic and stochastic processes might be mediated by aridity, salinity, and total phosphorus, although the mediations were opposite for bacteria and eukaryotes.
生物结皮在许多干旱地区发挥着关键的生态功能，但探索其群落组装过程具有挑战性，特别是在斑块状演替类型和跨越气候带的情况下。本研究在中国北方采集了不同演替阶段的生物结皮（藻类、地衣和苔藓为主的生物结皮），并通过高通量测序结合土壤性质和小气候环境的测量来研究生物结皮微生物群落的组装。细菌和真核生物群落表明，最大和最小的群落变化分别发生在经度和纬度上。在涉及生物结皮所有三个阶段的地区，演替阶段之间存在最大的群落差异，并且随着距离的增加而减小。群落组装通常受扩散限制驱动，尽管中性过程控制了超干旱地区的真核生物群落组装。随着演替的进行，细菌群落没有明显的模式，但真核生物群落表现出越来越高的同质性，物种分类增加，扩散限制降低，群落组装。与早期演替的生物结皮相比，后期阶段的微生物相互排斥更多，网络更复杂，具有明显的拓扑特征。相关分析进一步表明，确定性和随机性过程之间的平衡可能受到干旱、盐度和总磷的调节，尽管细菌和真核生物的调节作用相反。
