Understanding the environmental and biological mechanisms shaping latitudinal patterns in microbial diversity is challenging in the field of ecology. Although multiple hypotheses have been proposed to explain these patterns, a consensus has rarely been reached. Here, we conducted a large-scale field survey and microcosm experiments to investigate how environmental heterogeneity and putative trophic interactions (exerted by protist–bacteria associations and T4-like virus–bacteria associations) affect soil bacterial communities along a latitudinal gradient. We found that the microbial latitudinal diversity was kingdom dependent, showing decreasing, clumped, and increasing trends in bacteria, protists, and T4-like viruses, respectively. Climatic and edaphic drivers played predominant roles in structuring the bacterial communities, the intensity of the climatic effect increased sharply from 30°N to 32°N, whereas the intensity of the edaphic effect remained stable. Biotic associations were also essential in shaping the bacterial communities, with protist–bacteria associations showing a quadratic distribution, whereas virus–bacteria associations were significant only at high latitudes. The microcosm experiments further revealed that the temperature component, which is affiliated with climate conditions, is the primary regulator of trophic associations along the latitudinal gradient. Overall, our study highlights a previously underestimated mechanism of how the putative biotic interactions influence bacterial communities and their response to environmental gradients.

中文翻译：

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温度依赖性营养关联沿着纬度梯度调节土壤细菌群落


了解塑造微生物多样性纬度模式的环境和生物机制在生态学领域具有挑战性。尽管已经提出了多种假设来解释这些模式，但很少达成共识。在这里，我们进行了大规模的实地调查和微观实验，以研究环境异质性和假定的营养相互作用（由原生生物-细菌关联和 T4 样病毒-细菌关联产生）如何沿纬度梯度影响土壤细菌群落。我们发现微生物的纬度多样性是界相关的，细菌、原生生物和 T4 样病毒分别呈现出减少、聚集和增加的趋势。气候和土壤驱动因素在细菌群落结构中发挥着主导作用，气候影响的强度从30°N急剧增加到32°N，而土壤影响的强度保持稳定。生物关联对于塑造细菌群落也至关重要，原生生物-细菌关联呈现二次分布，而病毒-细菌关联仅在高纬度地区才显着。微观实验进一步表明，与气候条件相关的温度成分是沿纬度梯度营养关联的主要调节因素。总的来说，我们的研究强调了一种先前被低估的机制，即假定的生物相互作用如何影响细菌群落及其对环境梯度的响应。