AUTHOR=Li Yang , Jia Zhongjun , Sun Qingye , Cheng Jianhua , Yang Yang , Zhan Jing , Wang Dan 

TITLE=Plant-Mediated Changes in Soil N-Cycling Genes during Revegetation of Copper Mine Tailings

JOURNAL=Frontiers in Environmental Science

VOLUME=5

YEAR=2017

URL=https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2017.00079

DOI=10.3389/fenvs.2017.00079

ISSN=2296-665X

ABSTRACT=<p>Nitrogen limitation represents a major bottleneck during the revegetation of mine tailings. However, controls over key nitrogen-cycling genes in rhizospheric soils under differential vegetation management remain poorly understood. The abundance and transcriptional activity of nitrogen-cycling genes and the enzymatic activity of nitrogen transformation are mediated differentially during revegetation of mine tailings by <italic>Imperata cylindrica</italic> and <italic>Chrysopogon zizanioides</italic> plants. Results showed that the highest total organic carbon (TOC), total nitrogen (TN), and <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula>-N contents were found in the rhizosphere of <italic>I. cylindrica</italic>. The <italic>nifH</italic> gene abundances differed between <italic>I. cylindrica</italic> and <italic>C. zizanioides</italic>, and were higher in <italic>I. cylindrica</italic> which demonstrated by 3.39-fold higher mRNA transcript abundance of the <italic>nifH</italic> gene and a 2.15-fold higher nitrogen fixation rate in the rhizosphere. In addition, <italic>C. zizanioides</italic> exhibited a 4.94-fold higher transcript abundance of the archaeal <italic>amoA</italic> gene and the highest nitrification rate (1.706 ± 0.293 μg N-<inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>NO</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>-</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula> g<sup>−1</sup> h<sup>−1</sup>) in the rhizosphere. In conclusion, <italic>I. cylindrica</italic> and <italic>C. zizanioides</italic> stimulated the abundances and activities of <italic>nifH</italic> gene and archaeal <italic>amoA</italic> gene, respectively. In addition, <italic>I. cylindrica</italic> appears to be capable of enhancing nitrogen fixation and exhibited accelerated nitrogen accumulation, which may be particularly useful for the rehabilitation of mine tailings.</p>