Liu Yibo, Zhang Baiyu, Zhang Yixin, Shen Yanping, Cheng Cheng, Yuan Weilin, Guo Ping
Key Laboratory of Groundwater Resources and Environment Ministry of Education, College of New Energy and Environment, Jilin University, Changchun, 130012, People's Republic of China.
Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, 130012, People's Republic of China.
Microb Ecol. 2023 May;85(4):1236-1252. doi: 10.1007/s00248-022-02013-9. Epub 2022 May 2.
Microbes contribute to the organic matter decomposition (OMD) in river ecosystems. This study considers two aspects of OMD in river ecosystems which have not been examined in scientific studies previously, and these are the microbial interactions in OMD and the influence of environmental factors on microbial interactions. Cotton strip (CS), as a substitute for organic matter, was introduced to Luanhe River Basin in China. The results of CS assay, microbial sequencing, and redundancy analysis (RDA) showed that CS selectively enriched bacterial and fungal groups related to cellulose decomposition, achieving cotton strip decomposition (CSD). Bacterial phylum Proteobacteria and fungal phyla Rozellomycota and Ascomycota were the dominant groups associated with CSD. Network analysis and Mantel test results indicated that bacteria and fungi on CS cooperatively formed an interaction network to achieve the CSD. In the network, modules 2 and 4 were significantly positively associated with CSD, which were considered as the key modules in this study. The key modules were mainly composed of phyla Proteobacteria and Ascomycota, indicating that microbes in key modules were the effective decomposers of CS. Although keystone taxa were not directly associated with CSD, they may regulate the genera in key modules to achieve the CSD, since some keystone taxa were linked with the microbial genera associated with CSD in the key modules. Total nitrogen (TN) and temperature in water were the dominant environmental factors positively influenced CSD. The key modules 2 and 4 were positively influenced by water temperature and TN in water, respectively, and two keystone taxa were positively associated with TN. This profoundly revealed that water temperature and TN influenced the OMD through acting on the keystone taxa and key modules in microbial interactions. The research findings help us to understand the microbial interactions influenced by environmental factors in OMD in river ecosystems.
微生物对河流生态系统中的有机物质分解（OMD）有重要作用。本研究探讨了河流生态系统中有机物质分解的两个方面，这两个方面在以往的科学研究中尚未被涉及，即有机物质分解过程中的微生物相互作用以及环境因素对微生物相互作用的影响。在中国的滦河流域引入了棉条（CS）作为有机物质的替代物。棉条分析、微生物测序和冗余分析（RDA）的结果表明，棉条选择性地富集了与纤维素分解相关的细菌和真菌类群，实现了棉条分解（CSD）。变形菌门细菌以及罗兹菌门和子囊菌门真菌是与棉条分解相关的优势类群。网络分析和Mantel检验结果表明，棉条上的细菌和真菌协同形成了一个相互作用网络以实现棉条分解。在该网络中，模块2和模块4与棉条分解显著正相关，被认为是本研究中的关键模块。关键模块主要由变形菌门和子囊菌门组成，表明关键模块中的微生物是棉条的有效分解者。虽然关键类群与棉条分解没有直接关联，但它们可能通过调节关键模块中的属来实现棉条分解，因为一些关键类群与关键模块中与棉条分解相关的微生物属存在联系。水中的总氮（TN）和温度是对棉条分解有积极影响的主要环境因素。关键模块2和模块4分别受到水温以及水中总氮的积极影响，并且有两个关键类群与总氮呈正相关。这深刻揭示了水温和总氮通过作用于微生物相互作用中的关键类群和关键模块来影响有机物质分解。该研究结果有助于我们理解河流生态系统中有机物质分解过程中受环境因素影响的微生物相互作用。
