Protists are ubiquitous in soil, where they are key contributors to nutrient cycling and energy transfer. However, protists have received far less attention than other components of the soil microbiome. We used amplicon sequencing of soils from 180 locations across six continents to investigate the ecological preferences of protists and their functional contributions to belowground systems. We complemented these analyses with shotgun metagenomic sequencing of 46 soils to validate the identities of the more abundant protist lineages. We found that most soils are dominated by consumers, although parasites and phototrophs are particularly abundant in tropical and arid ecosystems, respectively. The best predictors of protist composition (primarily annual precipitation) are fundamentally distinct from those shaping bacterial and archaeal communities (namely, soil pH). Some protists and bacteria co-occur globally, highlighting the potential importance of these largely undescribed belowground interactions. Together, this study allowed us to identify the most abundant and ubiquitous protists living in soil, with our work providing a cross-ecosystem perspective on the factors structuring soil protist communities and their likely contributions to soil functioning.

中文翻译：

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土壤原生生物的全球分布及其对地下系统的贡献。

原生生物在土壤中无处不在，它们是养分循环和能量转移的关键贡献者。然而，与土壤微生物组的其他组成部分相比，原生生物受到的关注要少得多。我们对六大洲 180 个地点的土壤进行了扩增子测序，以研究原生生物的生态偏好及其对地下系统的功能贡献。我们通过对 46 种土壤进行鸟枪法宏基因组测序来补充这些分析，以验证更丰富的原生生物谱系的身份。我们发现，尽管热带和干旱生态系统中寄生虫和光养生物分别特别丰富，但大多数土壤以消费者为主。原生生物组成（主要是年降水量）的最佳预测因子与塑造细菌和古菌群落的预测因子（即土壤 pH 值）有着本质上的区别。一些原生生物和细菌在全球范围内共存，凸显了这些很大程度上未被描述的地下相互作用的潜在重要性。总之，这项研究使我们能够确定生活在土壤中最丰富和普遍的原生生物，我们的工作为构建土壤原生生物群落的因素及其对土壤功能的可能贡献提供了跨生态系统的视角。