Biological iron oxidation in paddy field soil: the potential role of microaerophilic iron-oxidizing bacteria

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05326
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Nagoya University
• Principal Investigator: Watanabe Takeshi 名古屋大学, 生命農学研究科, 准教授 (60547016)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 水田 / 鉄酸化菌

Outline of Final Research Achievements

This study analyzed the iron-oxidizing activity of microaerophilic iron oxidizer isolated from a paddy field and the dynamics of the microaerophilic iron-oxidizing bacterial (FeOB) community in paddy soils after drainage to evaluate the iron-oxidizing potential of the microaerophilic iron oxidizers in paddy soils. Soil incubation experiments revealed that the microaerophilic FeOB community was involved in the initial iron oxidation after draining, when the soil is marginally oxygenated, and that they proliferated significantly in a short period of time. The iron oxidation potential at that time was up to 0.03 mg Fe(II) per gram of dry soil, and it was indicated that they are mainly involved in the oxidation of ferrous iron ions in the soil solution.

Free Research Field

土壌微生物学

Academic Significance and Societal Importance of the Research Achievements

湛水と落水が繰り返される水田では、土壌中の鉄の酸化還元状態が大きく変化する。鉄の酸化還元反応は土壌中の炭素や窒素、その他様々な無機元素の動態にも影響を及ぼす重要な反応である。近年、微好気性鉄酸化細菌として知られるGallionellaceae科鉄酸化菌が、水田土壌の鉄酸化反応に関わることが明らかになってきたが、そのポテンシャルは不明であった。本研究では、土壌中での微好気性鉄酸化菌の鉄酸化ポテンシャルをはじめて評価した研究であり、今後、水田土壌中での鉄酸化反応に伴う物質動態の詳細を理解する上で貴重な知見を得た。