title: Rhizosphere bacterial communities of dominant steppe plants shift in response to a gradient of simulated nitrogen deposition.
abstract: 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.
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors: An
authors: A
authors: Yang
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China ; University of Chinese Academy of Sciences Beijing, China.
authors: Nana
authors: N
authors: Liu
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors: Qiuying
authors: Q
authors: Tian
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors: Wenming
authors: W
authors: Bai
authors: Department of Horticulture, Virginia Polytechnic Institute and State University Blacksburg, VA, USA.
authors: Mark
authors: M
authors: Williams
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors: Qibing
authors: Q
authors: Wang
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China.
authors: Linghao
authors: L
authors: Li
authors: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Beijing, China ; Research Network of Global Change Biology, Beijing Institutes of Life Science, Chinese Academy of Sciences Beijing, China.
authors: Wen-Hao
authors: WH
authors: Zhang
keywords: Artemisia frigida; Illumina Miseq; Stipa kerlovii; microbial diversity; nitrogen deposition; rhizosphere; temperate steppe