Intensively fertilized acidic soils are global hotspots of nitrous oxide (NO) emissions, contributing to net agronomic greenhouse gas outcomes. Identifying the key drivers of soil NO emissions is hampered by the synergistic or antagonistic effects of multiple factors. Within a framework based on the predominant role of microbial communities producing NO, the NO emissions are affected either by proximal regulators: temporary soil property fluctuations affect NO production transcriptionally, or by distal regulators: persistent genetic rearrangements in local microbial communities. The proximal regulators, individually or together, may spontaneously impact distal regulators. Here, we use acidic soils from tea ( L.) plantations on a broader geographic scale as a model system. Based on amplicon sequencing and properties of 195 acidic (average pH = 5.0) soils, we determined the importance of proximal and distal regulation to NO emissions. Microbial phylogenetic diversity as a distal regulator overwhelms mineral N content as a proximal regulator in explaining high NO emissions. Low-abundance, diverse prokaryotic communities (e.g., ) and specialized denitrifying fungal communities (e.g., ) were associated with high NO emissions. Revisiting the impact of proximal regulators on distal regulators revealed that soil pH is the sole proximal regulator influencing the prokaryotic rare taxa that correlated with high NO emissions. When considering proximal regulators together (here soil properties compiled as soil fertility index), the microbial diversity were independent of soil fertility. The microbial assembly was dominated by stochastic processes. Consequently, proximal regulators have a limited impact on distal regulators of NO emissions from acidic soils. In conclusion, the framework underscored the importance of microbial communities as distal regulators in explaining high NO emissions from acidic soils.

中文翻译：

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微生物群落压倒了环境控制来解释酸性土壤中一氧化二氮的排放

密集施肥的酸性土壤是全球一氧化二氮 (NO) 排放的热点，导致净农业温室气体排放。多种因素的协同或拮抗作用阻碍了土壤二氧化氮排放的关键驱动因素的识别。在基于产生 NO 的微生物群落的主导作用的框架内，NO 排放要么受到近端调节因子的影响：临时土壤特性波动会转录影响 NO 的产生，要么受到远端调节因子的影响：当地微生物群落中持续的基因重排。近端调节器单独或一起可能会自发地影响远端调节器。在这里，我们使用更广泛地理范围内的茶园（L.）的酸性土壤作为模型系统。根据扩增子测序和 195 种酸性（平均 pH = 5.0）土壤的特性，我们确定了近端和远端调节对 NO 排放的重要性。在解释高氮氧化物排放时，微生物系统发育多样性作为远端调节因子压倒了矿物质氮含量作为近端调节因子。低丰度、多样化的原核生物群落（例如 ）和专门的反硝化真菌群落（例如 ）与高 NO 排放相关。重新审视近端调节因子对远端调节因子的影响表明，土壤 pH 值是影响与高 NO 排放相关的原核稀有类群的唯一近端调节因子。当同时考虑近端调节因子时（此处土壤特性编制为土壤肥力指数），微生物多样性与土壤肥力无关。微生物组装以随机过程为主。因此，近端调节剂对酸性土壤 NO 排放的远端调节剂的影响有限。总之，该框架强调了微生物群落作为远端调节剂在解释酸性土壤高氮氧化物排放方面的重要性。