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Research

　水田生態系は、田面水、作土層土壌、作土下の下層土から成り、作土層土壌は表層数mmの作土酸化層とその下の作土還元層から成りたっています。また、水田生態系においては、浸透水がこれら各層を上から下に結びつけています。加えて、作土層には、水稲根系が発達し、多量の刈り株・残根や稲わらが鋤込まれています。これら各部位は、そこに生育する微生物にとってそれぞれ異なった環境であり、各部位に適応した微生物群集が生育しています。

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　Paddy field ecosystem is composed of surface water, plowed soil layer, and subsoil, and the plowed soil layer is divided into two layers; a thin oxidized soil layer and a reduced soil layer. These soil layers are connected by percolating water. In addition, rice roots are developed, and plant residues such as rice straw and stubble after rice harvest are incorporated into the plowed soil layer. These microsites are different habitats for microorganisms, and unique microbial communities inhabit them depending on the microsites.

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　水田に生息する微生物群集はウィルスに始まり、細菌、糸状菌、原生動物から構成され、各微生物は互いに影響を及ぼしあっています．例えば、地球温暖化ガス であるメタンは、メタン生成古細菌によって作られるが、その生成には共生菌の存在が不可欠です．また、生成したメタンは土壌中を移動する とともにメタン酸化菌によって分解され、メタン生成古細菌、メタン酸化菌は、そのウィルスや原生動物によって制御されています．

　本研究室では、全国各地の水田土壌を用いて、そこに生息する各種微生物の動態と微生物間相互作用を解析し、 水田生態系の生元素循環における微生物多様性と機能の実態と仕組みを解明することを目指しています。

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　Microbial communities in the paddy field ecosystems, which are composed of viruses, bacteria, archaea, fungi, and protists, have an impact on each other. For example, a supply of methanogenic substrates by symbiotic anaerobic bacteria is required to produce methane gas, one of the greenhouse gases, by methanogenic archaea. Methane is oxidized by methanotrophs in oxidized aerobic soil. The dynamics of methanogenic archaeal and methane-oxidizing bacterial communities are controlled by viruses and protists．
　The dynamics of soil microorganisms and their interactions in a paddy field ecosystem are the current central themes of this research group. The aim is to elucidate the facts and mechanisms of microbial diversity and functions in the cycle of bioelements in a paddy field ecosystem.

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Main Research Topics

水田土壌の物質循環と微生物

Biogeochemistry in paddy field soil

 

　関連論文 Related papers​​

  • 浅川 晋 2021：日本人の主食　お米の生産を支える微生物. 土と微生物, 75, 66-69. (J-STAGE link)

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  • 浅川晋 2006：水田土壌の機能と微生物群集構造，土と微生物，60(2)，79-84 (J-STAGE link)

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水田生態系のメタン生成・酸化に関わる微生物

Methanogenic archaea and methane-oxidizing bacteria in paddy field ecosystem​

 

　関連論文 Related papers

  • Hirotaka Kaise, Joseph Benewindé Sawadogo, Mohammad Saiful Alam, Chihoko Ueno, Dayéri Dianou, Rina Shinjo, Susumu Asakawa 2023: Methylocystis iwaonis sp. nov., a type II methane-oxidizing bacterium from surface soil of a rice paddy field in Japan, and emended description of the genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993. Int. J. Syst. Evol. Microbiol. 73, 005925. (view abstract)

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  • Rina Shinjo, Fumika Oe, Koki Nakagawa, Jun Murase, Susumu Asakawa, Takeshi Watanabe 2023: Type-specific quantification of particulate methane monooxygenase gene of methane-oxidizing bacteria at the oxic-anoxic interface of a surface paddy soil by digital PCR. Environ. Microbiol. Rep. 15, 392-403 (view full text)

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  • Susumu Asakawa 2021: Ecology of methanogenic and methane-oxidizing microorganisms in paddy soil ecosystem. Soil Sci. Plant Nutr. 67, 520-526. (view full text)​​

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  • 浅川 晋 2020：水田土壌生態系におけるメタンの生成・酸化に関わる微生物の生態に関する研究. 土肥誌, 91, 309-312. (J-STAGE link)

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  • 渡邉健史 2013：分子生態学的手法による水田土壌のメタン生成古細菌の動態と多様性に関する研究、 土肥誌, 84(5), 355-356. (J-STAGE link)

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  • 渡邉健史 2010：水田土壌に生息するメタン生成アーキア、生物工学会誌、88, 676. (view ful text)

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水田生態系の鉄酸化細菌・還元細菌に関する研究

Iron-oxidizinig bacteria and iron-reducing bacteria in paddy field ecosystem

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　関連論文 Related papers

  • Takeshi Watanabe, Kento Kato, Kohei, Kawaguchi, Toshiya Oga, Yoshinori Ban, Cécile Harmonie Otoidobiga, Adama Sawadogo, Issa Wonni, Léonard S. Ouedraogo, Jean Didier Zongo, Dayéri Dianou, Susumu Asakawa 2023: Investigation of iron-reducing and iron-oxidizing bacterial communities in the rice rhizosphere of iron-toxic paddy field: a case study in Burkina Faso, West Africa. Soil Sci. Plant Nutr. 69, 283-293 (view abstract)

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  • Takeshi Watanabe, Nobuko Katayanagi, Ruth Agbisit, Lizzida Llorca, Yasukazu Hosen, Susumu Asakawa 2021: Influence of alternate wetting and drying water-saving irrigation practice on the dynamics of Gallionella-related iron-oxidizing bacterial community in paddy field soil. Soil Biol. Biochem. 152, 108064 (view abstract)

 

  • Takeshi Watanabe, Ashraf Khalifa, Susumu Asakawa 2021: Complete genome sequence of Ferrigenium kumadai An22, a microaerophilic iron-oxidizing bacterium isolated from a paddy field soil. Microbiol. Resour. Announc. 10, e003346-21 (view full text)

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  • Koki Nakagawa, Jun Murase, Susumu Asakawa, Takeshi Watanabe 2020: Involvement of microaerophilic iron-oxidizing bacteria in the iron-oxidizing process at the surface layer of flooded paddy field soil. J. Soils Sediments 20, 4034-4041 (view abstract)

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  • Tatsushi Naruse, Yoshinori Ban, Tomofumi Yoshida, Takahiro Kato, Mari Namikawa, Tomoki Takahashi, Mizuhiko Nishida, Susumu Asakawa, Takeshi Watanabe 2019: Community structure of microaerophilic iron-oxidizing bacteria in Japanese paddy field soils. Soil Sci. Plant Nutr. 65, 460-470 (view full text)

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  • Ashraf Khalifa, Yuta Nakasuji, Norikuni Saka, Hiroki Honjo, Susumu Asakawa, Takeshi Watanabe 2018: Ferrigenium kumadai gen. nov., sp. nov., a microaerophilic iron-oxidizing bacterium isolated from a paddy field soil. Int. J. Syst. Evol. Microbiol. 68, 2587-2592. (view abstract)

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  • Takeshi Watanabe, Hiroaki Sumida, Nhut Minh Do, Katsuya Yano, Susumu Asakawa, Makoto Kimura 2013: Bacterial consortia in iron-deposited colonies formed on paddy soil surface under microaerobic conditions. Soil Sci. Plant Nutr. 59, 337-346. (view full text)

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水田生態系に生息する各種微生物の分離と特性解明

Isolation and characterization of microorganisms inhabiting paddy field ecosystem

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　関連論文 Related papers

  • Hirotaka Kaise, Joseph Benewindé Sawadogo, Mohammad Saiful Alam, Chihoko Ueno, Dayéri Dianou, Rina Shinjo, Susumu Asakawa 2023: Methylocystis iwaonis sp. nov., a type II methane-oxidizing bacterium from surface soil of a rice paddy field in Japan, and emended description of the genus Methylocystis (ex Whittenbury et al. 1970) Bowman et al. 1993. Int. J. Syst. Evol. Microbiol. 73, 005925. (view abstract)

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  • Takeshi Watanabe, Ashraf Khalifa, Susumu Asakawa 2021: Complete genome sequence of Ferrigenium kumadai An22, a microaerophilic iron-oxidizing bacterium isolated from a paddy field soil. Microbiol. Resour. Announc. 10, e003346-21 (view full text)

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  • Ashraf Khalifa, Yuta Nakasuji, Norikuni Saka, Hiroki Honjo, Susumu Asakawa, Takeshi Watanabe 2018: Ferrigenium kumadai gen. nov., sp. nov., a microaerophilic iron-oxidizing bacterium isolated from a paddy field soil. Int. J. Syst. Evol. Microbiol. 68, 2587-2592. (view abstract)

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  • Ryuko Baba, Susumu Asakawa, Takeshi Watanabe 2017: Transcription of [FeFe]-hydrogenase genes during H2 production in Clostridium and Desulfovibrio spp. isolated from a paddy field soil. Microbes Environ. 32, 125-132. (view full text)

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  • Ashraf Khalifa, Chol Gyu Lee, Takuya Ogiso, Chihoko Ueno, Dayeri Dianou, Toyoko Demachi, Arata Katayama, Susumu Asakawa 2015: Methylomagnum ishizawai gen. nov., sp. nov., a mesophilic type I methanotroph isolated from rice rhizosphere. Int. J. Syst. Evol. Microbiol., 65, 3527-3534. (view abstract)

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  • Takuya Ogiso, Chihoko Ueno, Dayeri Dianou, Tran Van Huy, Arata Katayama, Makoto Kimura, Susumu Asakawa 2012: Methylomonas koyamae sp. nov., a type I methane-oxidizing bacterium from floodwater of a rice paddy field. Int. J. Syst. Evol. Microbiol., 62, 1832-1837. (view abstract)

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  • Dayeri Dianou, Chihoko Ueno, Takuya Ogiso, Makoto Kimura, Susumu Asakawa 2012: Diversity of cultivable methane-oxidizing bacteria in microsites of a rice paddy field: investigation by cultivation method and fluorescence in situ hybridization (FISH). Microbes Environ., 27, 278-287. (view full text)

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分子生物学的手法による水田生態系の微生物群集の解析

Microbial community analysis in paddy field ecosystem

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　関連論文 Related papers

  • Rina Shinjo, Fumika Oe, Koki Nakagawa, Jun Murase, Susumu Asakawa, Takeshi Watanabe 2023: Type-specific quantification of particulate methane monooxygenase gene of methane-oxidizing bacteria at the oxic-anoxic interface of a surface paddy soil by digital PCR. Environ. Microbiol. Rep. 15, 392-403 (view full text)

​​

  • Takeshi Watanabe, Nobuko Katayanagi, Ruth Agbisit, Lizzida Llorca, Yasukazu Hosen, Susumu Asakawa 2021: Influence of alternate wetting and drying water-saving irrigation practice on the dynamics of Gallionella-related iron-oxidizing bacterial community in paddy field soil. Soil Biol. Biochem. 152, 108064 (view abstract)

​​

  • Koki Nakagawa, Jun Murase, Susumu Asakawa, Takeshi Watanabe 2020: Involvement of microaerophilic iron-oxidizing bacteria in the iron-oxidizing process at the surface layer of flooded paddy field soil. J. Soils Sediments 20, 4034-4041 (view abstract)

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  • Takeshi Watanabe, Susumu Asakawa, Koichi Hayano 2020: Long-term submergence of non-methanogenic oxic upland field soils helps to develop the methanogenic archaeal community as revealed by pot and field experiments. Pedosphere 30, 62-72 (view abstract)

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  • Dongyan Liu, Mizuhiko Nishida, Tomoki Takahashi, Susumu Asakawa 2018: Transcription of mcrA gene decreases upon prolonged non-flooding period in a methanogenic archaeal community of a paddy-upland rotational field soil. Microb. Ecol. 75, 751-760. (view abstract)

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  • Ryuko Baba, Susumu Asakawa, Takeshi Watanabe 2016: H2-producing bacterial community during rice straw decomposition in paddy field soil: estimation by an analysis of [FeFe]-hydrogenase gene transcripts. Microbes Environ., 31, 226-233. (view full text)

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  • Dongyan Liu, Hiroki Ishikawa, Mizuhiko Nishida, Kazunari Tsuchiya, Tomoki Takahashi, Makoto Kimura, Susumu Asakawa 2015: Effect of paddy-upland rotation on methanogenic archaeal community structure in paddy field soil. Microb. Ecol., 69, 160-168. (view abstract)

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​水田土壌中の微生物バイオマスカリウムの動態の解明

Microbial biomass potassium in paddy field soil

 

　関連論文 Related papers

  • Yoshiki Tokonami, Taketo Funao, Toshiya Oga, Mizuhiko Nishida, Tomoki Takahashi, Susumu Asakawa 2022: Estimation of turnover time of microbial biomass potassium in paddy field soil. Soil Sci. Plant Nutr. 68, 275-283 (view abstract)

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  • Kohei Yamashita, Mizuhiko Nishida, Kazunori Akita, Toyoaki Ito, Masanori Saito, Hiroki Honjo, Makoto Shinohara, Susumu Asakawa 2022: Pool size of microbial biomass potassium in various farmland soils. Soil Sci. Plant Nutr. 68, 400-408 (view abstract)

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  • Kohei Yamashita, Hiroki Honjo, Makoto Shinohara, Susumu Asakawa 2018: Conversion factor (k factor) for estimation of soil microbial biomass potassium by the chloroform-fumigation extraction method. Soil Sci. Plant Nutr. 64, 465-468. (view full text)

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  • 浅川　晋・山下昴平 2017：植物へのカリウム供給源としての土壌微生物バイオマスー土壌微生物は窒素やリンだけでなくカリウムも抱え込んでいる. 化学と生物，55，444-445. (view full text)

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  • Kohei Yamashita, Hiroki Honjo, Mizuhiko Nishida, Makoto Kimura, Susumu Asakawa 2014: Estimation of microbial biomass potassium in paddy field soil. Soil Sci. Plant Nutr., 60, 512-519 (Corrigendum [2016] 62, 570-573). (view abstract)

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