Submillimeter-scale visualization of rhizosphere effect using Cryo-TOF-SIMS/SEM

• Project/Area Number: 16K15075
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental agriculture(including landscape science)
• Research Institution: Nagoya University
• Principal Investigator: Murase Jun 名古屋大学, 生命農学研究科, 教授 (30285241)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 水稲 / 根圏効果 / 化学環境 / 濃度勾配 / 根圏 / 微生物 / 原生生物 / 根滲出物 / 根浸出物

Outline of Final Research Achievements

Chemical environments of rice rhizosphere were visualized at the submillimeter scale. Roots of rice seedlings grown in soft agar media were sampled together with the surrounding media without destruction of rhizosphere structure, and the distribution of dissolve compounds in the shock frozen root and rhizosphere was analyzed by using the Cryo-TOF-SIMS/SEM system. The results successfully demonstrated the chemical gradients in the rice rhizosphere within a several hundred micrometers. Environmental gradients in the rice rhizosphere were also demonstrated from the spatial distribution of protists. In addition, we showed that protozoan grazing plays a pivotal role in shaping the bacterial community in the rice rhizosphere.

Academic Significance and Societal Importance of the Research Achievements

植物根からの浸出物の供給による根圏効果は広く知られた事実であるが、周辺微小生態系への影響についての空間的情報はほとんど得られていなかった。根圏の化学環境をサブミリスケールで解析した本研究の成果は、植物と土壌微生物の相互作用のホットスポットである根圏環境の研究の新たなアプローチ、またCryo-TOF-SIMS/MSのポテンシャルを提示するものである。また、本研究で開発したガラス製ミニ根箱は、化学環境と微生物環境の同時可視化を実現した。

Research Products

• [Journal Article] Microhabitat segregation of heterotrophic protists in the rice (Oryza sativa L.) rhizosphere (2017)
  • Author(s): Asiloglu, Rasit Murase, Jun
  • Journal Title: Rhizosphere Volume: 4 Pages: 82-88
  • DOI: 10.1016/j.rhisph.2017.08.001
  • Peer Reviewed / Open Access
• [Journal Article] Quest of Soil Protists in a New Era (2017)
  • Author(s): Murase, Jun
  • Journal Title: Microbes and Environments Volume: 32 Issue: 2 Pages: 99-102
  • DOI: 10.1264/jsme2.ME3202rh
  • NAID: 130006789904
  • ISSN: 1342-6311, 1347-4405
  • Peer Reviewed / Open Access
• [Presentation] 水稲根圏の細菌群集に及ぼす原生生物の影響 (2019)
  • Author(s): 永井裕也・村瀬 潤
  • Organizer: 日本土壌微生物学会2019年度大会
• [Presentation] 田んぼの中の原生生物たちの暮らし (2019)
  • Author(s): 村瀬 潤
  • Organizer: 日本土壌微生物学会2019年度大会
  • Invited
• [Presentation] Ecology of protists in a rice rhizosphere (2018)
  • Author(s): Jun MURASE
  • Organizer: International Workshop of Mollisols Ecology
  • Int'l Joint Research / Invited
• [Presentation] The effect of humic substances on the methanogenic microbial community in the artificial rice field soil (2018)
  • Author(s): Yu Maeda, Jun Murase
  • Organizer: 17th International Symposium on Microbial Ecology
  • Int'l Joint Research
• [Presentation] 水稲根圏における原生生物の生態と機能 (2017)
  • Author(s): 村瀬 潤
  • Organizer: 大気-森林-土壌循環ワークショップ
  • Invited