| Project/Area Number |
18K14366
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 38010:Plant nutrition and soil science-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Masuda Yoko 東京大学, 大学院農学生命科学研究科(農学部), 特任研究員 (80813237)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | 鉄還元菌 / 窒素固定 / 水田土壌 / メタゲノム / Geomonas / Oryzomonas / Anaeromyxobacter / Geobacter / メタゲノム解析 / 安定同位体 / 土壌 |
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| Outline of Final Research Achievements |
In our metagenomic analysis of the terrestrial soils around the world, nif genes derived from iron-reducing bacteria were detected in 79 among 127 sites. The nif genes derived from iron-reducing bacteria was frequently detected not only in paddy soils but also in the forest, desert, and polar soils. These results suggested that nitrogen fixation by iron-reducing bacteria is a universal phenomenon in the soil environment.
We verified, for the first time, the nitrogen-fixing activity of Anaeromyxobacter isolated from paddy soil, both in culture medium and soil microcosm. In addition, we successfully isolated several strains of iron-reducing belonging to new genera, Geomonas and Oryzomonas, and confirmed their nitrogen-fixing activity.
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| Academic Significance and Societal Importance of the Research Achievements |
窒素固定は大気中の窒素ガスを生物が利用できる形態の窒素に変換して土壌に供給する重要な反応である。19世紀末にはじめて窒素固定が発見されて以降、「土壌の窒素固定は植物共生細菌や光合成細菌が担う」というのが一般常識であった。しかし本研究により、窒素固定できる鉄還元菌が地球規模で普遍的に分布していること、そして既知の窒素固定細菌群よりも存在量が多い傾向も見出された。このことは窒素固定に関する定説を刷新して自然生態系の支持基盤の本質に迫るものであり、土壌学分野だけでなく、微生物学、地球科学、生態学といった自然科学分野全般において意義を持つ。
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