Rhizosphere bacterial communities of dominant steppe plants shift in response to a gradient of simulated nitrogen deposition.
Rhizosphere bacterial communities of dominant steppe plants shift in response to a gradient of simulated nitrogen deposition.
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优势草原植物的根际细菌群落响应模拟氮沉降梯度而变化
DOI：
10.3389/fmicb.2015.00789
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发表时间：
2015
影响因子：
5.2
通讯作者：
Zhang WH
中科院分区：
文献类型：
--
作者：
Yang A;Liu N;Tian Q;Bai W;Williams M;Wang Q;Li L;Zhang WH
研究了9年模拟氮沉降对两种优势温带草地物种克氏针茅（Stipa krylovii）和冷蒿（Artemisia frigida）根际微生物组成和多样性的影响。S. krylovii和A.根际土壤氮素含量不同，但沿氮素梯度变化沿着一致。这些变化与N诱导的植物群落转移有关。因此，随着植物生物量的变化，细菌根际群落也发生了变化，这一结果与氮肥在改变植物-微生物互惠关系中所起的作用一致。焦磷酸测序结果表明，两种根际土壤中共有23个细菌门，其中变形菌门、酸杆菌门和拟杆菌门占优势。拟杆菌和变形菌有增加的趋势，而酸性细菌下降，随着氮添加率的增加。TM7在高氮水平下生长量增加5倍以上，尤其是S。克氏根际氮添加还降低了OTU（操作分类单位），香农和Chao1指数的根际微生物的多样性，无论植物物种。这些结果表明，由于氮沉降，温带草原微生物群落既有相似的，但也有特定的变化。这些发现将有助于我们从植物性状的变化与根际微生物介导的过程联系起来，从机理上理解氮沉降对草地生态系统的影响。
We evaluated effects of 9-year simulated nitrogen (N) deposition on microbial composition and diversity in the rhizosphere of two dominant temperate grassland species: grass Stipa krylovii and forb Artemisia frigida. Microbiomes in S. krylovii and A. frigida rhizosphere differed, but changed consistently along the N gradient. These changes were correlated to N-induced shifts to plant community. Hence, as plant biomass changed, so did bacterial rhizosphere communities, a result consistent with the role that N fertilizer has been shown to play in altering plant-microbial mutualisms. A total of 23 bacterial phyla were detected in the two rhizospheric soils by pyrosequencing, with Proteobacteria, Acidobacteria, and Bacteroidetes dominating the sequences of all samples. Bacterioidetes and Proteobacteria tended to increase, while Acidobacteria declined with increase in N addition rates. TM7 increased >5-fold in the high N addition rates, especially in S. krylovii rhizosphere. Nitrogen addition also decreased diversity of OTUs (operational taxonomic units), Shannon and Chao1 indices of rhizospheric microbes regardless of plant species. These results suggest that there were both similar but also specific changes in microbial communities of temperate steppes due to N deposition. These findings would contribute to our mechanistic understanding of impacts of N deposition on grassland ecosystem by linking changes in plant traits to their rhizospheric microbes-mediated processes.