State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural Universitygrid.35155.37, Wuhan, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural Universitygrid.35155.37, Wuhan, China.
Appl Environ Microbiol. 2021 Oct 14;87(21):e0136621. doi: 10.1128/AEM.01366-21. Epub 2021 Aug 18.
Salinization is considered a major threat to soil fertility and agricultural productivity throughout the world. Soil microbes play a crucial role in maintaining ecosystem stability and function (e.g., nitrogen cycling). However, the response of bacterial community composition and community-level function to soil salinity remains uncertain. Here, we used multiple statistical analyses to assess the effect of high salinity on bacterial community composition and potential metabolism function in the agricultural ecosystem. Results showed that high salinity significantly altered both bacterial alpha (Shannon-Wiener index and phylogenetic diversity) and beta diversity. Salinity, total nitrogen (TN), and soil organic matter (SOM) were the vital environmental factors shaping bacterial community composition. The relative abundance of , , , and decreased with salinity, whereas and increased with salinity. The modularity and the ratio of negative to positive links remarkedly decreased, indicating that high salinity destabilized bacterial networks. Variable selection, which belongs to deterministic processes, mediated bacterial community assembly within the saline soils. Function prediction results showed that the key nitrogen metabolism (e.g., ammonification, nitrogen fixation, nitrification, and denitrification processes) was inhibited in high salinity habitats. MiSeq sequencing of 16S rRNA genes revealed that the abundance and composition of the nitrifying community were influenced by high salinity. The consistency of function prediction and experimental verification demonstrated that high salinity inhibited soil bacterial community mediating nitrogen cycling. Our study provides strong evidence for a salinity effect on the bacterial community composition and key metabolism function, which could help us understand how soil microbes respond to ongoing environment perturbation. Revealing the response of the soil bacterial community to external environmental disturbances is an important but poorly understood topic in microbial ecology. In this study, we evaluated the effect of high salinity on the bacterial community composition and key biogeochemical processes in salinized agricultural soils (0.22 to 19.98 dS m). Our results showed that high salinity significantly decreased bacterial diversity, altered bacterial community composition, and destabilized the bacterial network. Moreover, variable selection (61% to 66%) mediated bacterial community assembly within the saline soils. Functional prediction combined with microbiological verification proved that high salinity inhibited soil bacterial community mediating nitrogen turnover. Understanding the impact of salinity on soil bacterial community is of great significance for managing saline soils and maintaining a healthy ecosystem.
盐渍化被认为是全世界土壤肥力和农业生产力的主要威胁。土壤微生物在维持生态系统稳定性和功能（例如氮循环）方面发挥着至关重要的作用。然而，细菌群落组成和群落水平功能对土壤盐分的响应仍不确定。在这里，我们使用多种统计分析来评估高盐度对农业生态系统中细菌群落组成和潜在代谢功能的影响。结果表明，高盐度显著改变了细菌的α多样性（香农-威纳指数和系统发育多样性）和β多样性。盐度、总氮 (TN) 和土壤有机质 (SOM) 是塑造细菌群落组成的重要环境因素。 、 、 、 和 的相对丰度随着盐度的升高而降低，而 和 的相对丰度随着盐度的升高而升高。模块性和负链与正链的比值显著降低，表明高盐度使细菌网络不稳定。属于确定性过程的变量选择介导了盐渍土壤中细菌群落的组装。功能预测结果表明，关键氮代谢（例如氨化、固氮、硝化和反硝化过程）在高盐度生境中受到抑制。16S rRNA 基因的 MiSeq 测序结果表明，硝化群落的丰度和组成受高盐度影响。功能预测与实验验证的一致性表明，高盐度抑制了土壤细菌群落介导的氮循环。我们的研究为盐度对细菌群落组成和关键代谢功能的影响提供了有力证据，这有助于我们了解土壤微生物如何应对持续的环境干扰。揭示土壤细菌群落对外界环境干扰的响应是微生物生态学中一个重要但知之甚少的课题。在这项研究中，我们评估了高盐度对盐渍化农业土壤（0.22 至 19.98 dS m）中细菌群落组成和关键生物地球化学过程的影响。我们的结果表明，高盐度显著降低了细菌多样性，改变了细菌群落组成，并使细菌网络不稳定。此外，变量选择（61%至 66%）介导了盐渍土壤中细菌群落的组装。功能预测与微生物验证相结合证明，高盐度抑制了土壤细菌群落介导的氮转化。了解盐度对土壤细菌群落的影响对于管理盐渍土壤和维持健康的生态系统具有重要意义。
