Ecological role of primitive nitrogen-fixing bacteria in hydrothermal chemosynthetic ecosystems

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K16234
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45040:Ecology and environment-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Nishihara Arisa 国立研究開発法人産業技術総合研究所, 生命工学領域, 学振特別研究員 (80837774)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 微生物生態系 / 物質循環 / 窒素固定 / 微生物培養 / 進化 / 発酵細菌

Outline of Final Research Achievements

In this study, we isolated a novel fermentative bacterium belonging to the phylum Firmicutes from the hydrothermal chemosynthetic microbial community that is able to fix nitrogen at temperatures above 70 degrees Celsius. Genome analysis of the isolates revealed that the isolate possess a distinctive set of nitrogen-fixing genes, which is different from that of conventional nitrogen-fixing bacteria. Phylogenetic analysis of the nitrogen-fixing genes revealed that the genes of the isolate are phylogenetically close to those of hyperthermophilic Archaea. The phylogenetic tree of nitrogen-fixing genes indicates that the isolate has acquired nitrogen-fixing ability together with hyperthermophilic archaea, and is an early nitrogen-fixing organism.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

窒素固定細菌は原始地球が高温であった約35億年前に、化学合成生態系で出現したとされるにも関わらず、これまで高温ではあまり研究されてこなかった。高温の化学合成生態系における窒素固定の研究は、生態系における窒素固定細菌の生態的役割だけでなく、窒素固定の進化的観点においても重要な研究課題である。