Microorganisms are crucial in mediating N cycles in soil and produce impact on the health and nutrition of the host plant. The seedling stage is one of the most critical periods of crop growth and development. However, the information regarding the underlying interactions between soil microbial community, soil nutrient, enzyme activities, and microbial biomass, and whether they associate with nitrogen use efficiency (NUE) of N at the rice (Oryza sativa L.) seedling stage are still limited. We applied 16S ribosomal RNA gene profiling to characterize root bacterial microbiota of rice varieties with different levels of NUE at the seedling stage. We find that high nitrogen use efficiency varieties (HNUEs) and low nitrogen use efficiency varieties (LNUEs) recruit distinct root microbiota. Notably, HNUEs‐enriched bacterial taxa are more diverse, and contain more operational taxonomic units (OTUs) with N metabolism functions, than LNUEs‐enriched taxa. We provide evidence that the content of available N and the microbial biomass of HNUEs' rhizospheric soil are higher than those of LNUEs. Through redundancy analysis (RDA), we found that Deltaproteobacteria, Acidobacteria, Bacteroidia, and Saccharimonadia with the potential function of the beneficial microorganism to seedling N use and growth. The links between rice seedling and soil microbiota membership combine with other essential factors established in this study could contribute to improving N use at the crop seedling stage to promote the resistance and survival rate after transplanting.

中文翻译：

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根际细菌群落，酶活性和土壤特性影响水稻幼苗的氮素利用

微生物对于介导土壤中的N循环至关重要，并对宿主植物的健康和营养产生影响。苗期是作物生长发育的最关键时期之一。但是，有关土壤微生物群落，土壤养分，酶活性和微生物生物量之间潜在相互作用的信息，以及它们是否与水稻（水稻）上氮素的氮利用效率（NUE）有关L.）苗期仍然有限。我们应用16S核糖体RNA基因图谱来表征具有不同NUE水平的水稻品种在苗期的根系细菌菌群。我们发现高氮利用效率品种（HNUEs）和低氮利用效率品种（LNUEs）会吸收不同的根微生物。值得注意的是，富含HNUE的细菌类群比富含LNUE的细菌类群具有更多的具有N代谢功能的操作分类单位（OTU）。我们提供的证据表明，HNUEs根际土壤中的有效氮含量和微生物量高于LNUEs。通过冗余分析（RDA），我们发现了Deltaproteobacteria，Acidobacteria，Bacteroidia和Saccharimonadia具有有益微生物对幼苗氮素利用和生长的潜在功能。水稻幼苗与土壤微生物区系成员之间的联系与本研究中建立的其他必要因素相结合，可有助于改善作物幼苗期的氮素利用，从而提高移栽后的抗性和存活率。