Soil micronutrients are increasingly recognized as critical regulators of biogeochemical cycling and terrestrial ecosystem processes. Despite substantial efforts establishing how belowground microbial communities respond to macronutrients such as N and P, responses to micronutrients remain poorly understood. This is of particular interest in tropical soils, where micronutrients are heterogeneously distributed and often deficient. Using nearly 300 soil samples that span broad gradients in soil micronutrients, we aimed to determine how differences in micronutrients (Ca, Mg, S) and secondary macronutrients (Mn, Fe, Zn) shape soil bacterial communities and their metabolic capabilities. Along with key soil parameters including pH and climatic predictors, we found that Ca, Mg, and Mn were important in shaping the composition and function of soil microbiomes. We also identified lineages that were consistently responsive to specific micronutrients, with those taxa found in low micronutrient conditions often associated with oligotrophic life history strategies. We detected a subset of metabolic attributes related to nutrient cycling that were strongly associated with specific micronutrients. Notably, Mn was important in predicting the abundance of gene systems related to P metabolism including control of Pho regulon and alkylphosphonate utilization, suggesting that it may be important mediators of these responses. Taken together, our results begin to establish a broader understanding of the extent to which belowground systems are shaped by micronutrients and the strategies that soil microbes employ in variable micronutrient environments.

中文翻译：

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微量营养素调节土壤细菌群落的结构和功能

土壤微量营养素越来越被认为是生物地球化学循环和陆地生态系统过程的关键调节剂。尽管做出了大量努力来确定地下微生物群落如何对氮和磷等常量营养素做出反应，但对微量营养素的反应仍然知之甚少。这在热带土壤中尤其重要，因为热带土壤中的微量营养素分布不均匀且常常缺乏。我们使用近 300 个涵盖土壤微量营养素大梯度的土壤样本，旨在确定微量营养素（Ca、Mg、S）和次要大量营养素（Mn、Fe、Zn）的差异如何影响土壤细菌群落及其代谢能力。除了 pH 值和气候预测因子等关键土壤参数外，我们发现 Ca、Mg 和 Mn 对于塑造土壤微生物组的组成和功能也很重要。我们还确定了对特定微量营养素持续敏感的谱系，这些在低微量营养素条件下发现的类群通常与寡营养生活史策略相关。我们检测到与营养循环相关的代谢属性的子集，这些属性与特定的微量营养素密切相关。值得注意的是，Mn 对于预测与 P 代谢相关的基因系统的丰度非常重要，包括控制 Pho 调节子和烷基磷酸盐的利用，这表明它可能是这些反应的重要介质。总而言之，我们的研究结果开始对微量营养素塑造地下系统的程度以及土壤微生物在可变微量营养素环境中采用的策略建立更广泛的理解。