Soil pH is a major factor shaping bulk soil microbial communities. However, it is unclear whether the belowground microbial habitats shaped by plants (e.g. rhizosphere and root endosphere) are also affected by soil pH. We investigated this question by comparing the microbial communities associated with plants growing in neutral and strongly alkaline soils in the Sandhills, which is the largest sand dune complex in the northern hemisphere. Bulk soil, rhizosphere and root endosphere DNA were extracted from multiple plant species and analyzed using 16S rRNA amplicon sequencing. Results showed that rhizosphere, root endosphere and bulk soil microbiomes were different in the contrasting soil pH ranges. The strongest impact of plant species on the belowground microbiomes was in alkaline soils, suggesting a greater selective effect under alkali stress. Evaluation of soil chemical components showed that in addition to soil pH, cation exchange capacity also had a strong impact on shaping bulk soil microbial communities. This study extends our knowledge regarding the importance of pH to microbial ecology showing that root endosphere and rhizosphere microbial communities were also influenced by this soil component, and highlights the important role that plants play particularly in shaping the belowground microbiomes in alkaline soils.

中文翻译：

---

碱性土壤 pH 值影响在 Sandhills 生态系统中生长的植物的大块土壤、根际和根内微生物组

土壤 pH 值是影响大量土壤微生物群落的主要因素。然而，目前尚不清楚植物形成的地下微生物栖息地（如根际和根内圈）是否也受到土壤 pH 值的影响。我们通过比较与在北半球最大的沙丘复合体沙丘中的中性和强碱性土壤中生长的植物相关的微生物群落来研究这个问题。从多种植物物种中提取大块土壤、根际和根内球 DNA，并使用 16S rRNA 扩增子测序进行分析。结果表明，在不同的土壤 pH 值范围内，根际、根内圈和大块土壤微生物组是不同的。植物物种对地下微生物组的最强影响是在碱性土壤中，这表明在碱胁迫下具有更大的选择性作用。对土壤化学成分的评估表明，除了土壤 pH 值外，阳离子交换能力对大量土壤微生物群落的形成也有很大影响。这项研究扩展了我们关于 pH 值对微生物生态学重要性的认识，表明根内圈和根际微生物群落也受到这种土壤成分的影响，并强调了植物在塑造碱性土壤中的地下微生物组方面所起的重要作用。