Zhou Hong, Yu Ke, Deng Chunfang, Wu Bo, Gao Ying
Academy of Agriculture and Forestry Sciences, Qinghai University, Xining, China.
Institute of Ecological Conservation and Restoration, Chinese Academy of Forestry, Beijing, China.
Front Microbiol. 2024 Aug 23;15:1404602. doi: 10.3389/fmicb.2024.1404602. eCollection 2024.
Biological soil crusts (biocrusts) constitute a crucial biological component of the soil surface in arid and semi-arid ecosystems. Understanding the variations in soil microbial community assembly across biocrust successional stages is essential for a deeper comprehension of microbial biodiversity and desert ecosystem functioning. However, knowledge about the mechanisms of microbial community assembly and the factors influencing its development remains limited. In this study, we utilized amplicons sequencing to assess the compositions of bacterial and fungal communities in bare sand and three types of biocrusts (light cyanobacterial biocrusts, dark cyanobacterial biocrusts, and moss crusts). Subsequently, we analyzed the ecological processes shaping microbial community composition and structure, along with the influencing factors. Our results revealed a significant increase in bacterial diversity and no significant changes in fungal diversity during biocrust development. The relative abundances of the copiotrophic bacteria (e.g., Actinobacteria, Acidobacteria, and Bacteroidetes) showed significant increases, while oligotrophic bacteria (e.g., Proteobacteria and Firmicutes) decreased over time. Moreover, the relative abundances of Ascomycota, which exhibit strong resistance to adverse environmental conditions, significantly decreased, whereas Basidiomycota, known for their ability to degrade lignin, significantly increased throughout biocrust development. Additionally, stochastic processes (dispersal limitation and drift) predominantly drove the assemblies of both bacterial and fungal communities. However, the relative importance of deterministic processes (homogeneous selection) in bacterial assembly increased during biocrust development. Structural equation modeling indicated that bacterial community assembly was primarily related to soil water content, whereas fungal community assembly was primarily related to total organic carbon. These findings provide a scientific foundation for investigating the formation and development of biocrusts, and further insights into the conservation and sustainable management of biocrust resources under future climate change scenarios.
生物土壤结皮（生物结皮）是干旱和半干旱生态系统土壤表面的重要生物组成部分。了解生物结皮演替阶段土壤微生物群落组装的变化，对于深入理解微生物多样性和沙漠生态系统功能至关重要。然而，关于微生物群落组装机制及其发展影响因素的知识仍然有限。在本研究中，我们利用扩增子测序评估了裸沙地和三种类型生物结皮（浅色蓝藻生物结皮、深色蓝藻生物结皮和苔藓结皮）中细菌和真菌群落的组成。随后，我们分析了塑造微生物群落组成和结构的生态过程以及影响因素。我们的结果表明，在生物结皮发育过程中细菌多样性显著增加，而真菌多样性没有显著变化。富营养细菌（如放线菌、酸杆菌和拟杆菌）的相对丰度显著增加，而贫营养细菌（如变形菌门和厚壁菌门）随时间减少。此外，对不利环境条件具有较强抗性的子囊菌门的相对丰度显著下降，而以降解木质素能力著称的担子菌门在整个生物结皮发育过程中显著增加。此外，随机过程（扩散限制和漂变）主要驱动细菌和真菌群落的组装。然而，在生物结皮发育过程中，确定性过程（同质选择）在细菌组装中的相对重要性增加。结构方程模型表明，细菌群落组装主要与土壤含水量有关，而真菌群落组装主要与总有机碳有关。这些发现为研究生物结皮的形成和发展提供了科学依据，并为未来气候变化情景下生物结皮资源的保护和可持续管理提供了进一步的见解。
