Low Nitrogen Fertilization Adapts Rice Root Microbiome to Low Nutrient Environment by Changing Biogeochemical Functions

作者：Ikeda Seishi; Sasaki Kazuhiro; Okubo Takashi; Yamashita Akifumu; Terasawa Kimihiro; Bao Zhihua; Liu Dongyan; Watanabe Takeshi; Murase Jun; Asakawa Susumu; Eda Shima; Mitsui Hisayuki; Sato Tadashi; Minamisawa Kiwamu^*

来源：Microbes and Environments, 2014, 29(1): 50-59.

DOI：10.1264/jsme2.ME13110

• rice paddy field
• nitrogen fertilizer
• methane cycle
• metagenome analysis
• root microbiome

Reduced fertilizer usage is one of the objectives of field management in the pursuit of sustainable agriculture. Here, we report on shifts of bacterial communities in paddy rice ecosystems with low (LN), standard (SN), and high (HN) levels of N fertilizer application (0, 30, and 300 kg N ha(-1), respectively). The LN field had received no N fertilizer for 5 years prior to the experiment. The LN and HN plants showed a 50% decrease and a 60% increase in biomass compared with the SN plant biomass, respectively. Analyses of 16S rRNA genes suggested shifts of bacterial communities between the LN and SN root microbiomes, which were statistically confirmed by metagenome analyses. The relative abundances of Burkholderia, Bradyrhizobium and Methylosinus were significantly increased in root microbiome of the LN field relative to the SN field. Conversely, the abundance of methanogenic archaea was reduced in the LN field relative to the SN field. The functional genes for methane oxidation (pmo and mmo) and plant association (acdS and iaaMH) were significantly abundant in the LN root microbiome. Quantitative PCR of pmoA/mcrA genes and a C-13 methane experiment provided evidence of more active methane oxidation in the rice roots of the LN field. In addition, functional genes for the metabolism of N, S, Fe, and aromatic compounds were more abundant in the LN root microbiome. These results suggest that low-N-fertilizer management is an important factor in shaping the microbial community structure containing key microbes for plant associations and biogeochemical processes in paddy rice ecosystems.

• 出版日期2014-4-2