Root associated microbes are key players in plant health, disease resistance, and nitrogen (N) use efficiency. It remains largely unclear how the interplay of biological and environmental factors affects rhizobiome dynamics in agricultural systems. Here, we quantified the composition of rhizosphere and bulk soil microbial communities associated with maize (Zea mays L.) and soybean (Glycine max L.) in a long-term crop rotation study under conventional fertilization and low N regimes. Over two growing seasons, we evaluated the effects of environmental conditions and several treatment factors on the abundance of rhizosphere and soil colonizing microbial taxa. Time of sampling, host plant species and N fertilization had major effects on microbiomes, while no effect of crop rotation was observed. Using variance partitioning as well as 16S sequence information, we further defined a set of 82 microbial genera and sub-genus groups that show distinct responses to treatment factors. We identified taxa that are highly specific to either maize or soybean rhizospheres, as well as taxa that are sensitive to N fertilization in plant rhizospheres and bulk soil. This study provides insights to harness the full potential of soil microbes in maize and soybean agricultural systems through plant breeding and field management.

中文翻译：

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历史玉米/大豆轮作系统中的根际微生物群对属和亚属水平的寄主物种和氮肥的响应

根系相关微生物是植物健康，抗病性和氮（N）利用效率的关键因素。生物学和环境因素的相互作用如何影响农业系统中的根瘤菌组动力学尚不清楚。在这里，我们在常规施肥和低氮制度下的长期作物轮作研究中，定量了与玉米（Zea mays L.）和大豆（Glycine max L.）相关的根际和土壤微生物群落组成。在两个生长季节中，我们评估了环境条件和几种处理因素对根际和土壤定殖微生物类群数量的影响。采样时间，寄主植物种类和氮肥对微生物群落有重要影响，而没有观察到作物轮作的影响。使用方差划分以及16S序列信息，我们进一步定义了一组82个微生物属和亚属组，这些组显示了对治疗因子的不同响应。我们确定了对玉米或大豆根际高度特异性的分类单元，以及对植物根际和大块土壤中氮肥敏感的分类单元。这项研究提供了洞察力，可以通过植物育种和田间管理来利用玉米和大豆农业系统中土壤微生物的全部潜力。