Novel function of the post-Koch ecosystem found only on microbial consortia

2023 Fiscal Year Final Research Report

• Project Area: Post-Koch Ecology: The next-era microbial ecology that elucidates the super-terrestrial organism system
• Project/Area Number: 19H05686
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Complex systems
• Research Institution: The University of Tokyo
• Principal Investigator: Nojiri Hideaki 東京大学, 大学院農学生命科学研究科(農学部), 教授 (90272468)
• Co-Investigator(Kenkyū-buntansha): 新谷 政己 静岡大学, 工学部, 准教授 (20572647)
• Project Period (FY): 2019-06-28 – 2024-03-31
• Keywords: 微生物間相互作用 / 複合系 / 環境汚染物質 / 分解菌 / プラスミド / 接合伝達

Outline of Final Research Achievements

In order to analyze the interactions between the pollutant-degrading bacteria and surrounding bacteria under the natural environmental condition, we developed Post-Koch techniques based on the “isolated cultivation” and/or “single-cell inoculation”. By using these, we were able to easily obtain a diverse group of degradative bacteria and easily detect interactions that affect their function. We also applied the developed techniques to detect interactions between important bacteria isolated from the model field soil and other bacteria.
Meanwhile, we obtained a large number of different plasmids from model fields. Based on their nucleotide sequences and basic functions (conjugation and replication host ranges), we classified the isolated plasmids and discussed the plasmid dynamics in model field environments. We also developed a method to predict conjugation host range and compiled a high-precision plasmid database.

Free Research Field

環境微生物学

Academic Significance and Societal Importance of the Research Achievements

環境中での微生物間相互作用は、従来の方法論では偶然見つかる場合がほとんどで、全貌解明にはほど遠いのが実情であった。本研究は、相互作用を簡単に探せる系を開発し、それらが環境汚染物質分解菌等の相互作用検出に有用なことを実証したもので、他の分野にも応用可能な重要な方法論を提供するものである。また、環境中での遺伝子水平伝播の実態を生態学的に捉えた例は少ないが、本研究ではモデル圃場内でのプラスミド動態を高精細に明らかにした。この成果は、環境細菌の機能的進化といった基礎的観点のみならず、薬剤耐性能の蔓延などの社会問題を解決する上でも重要と言え、環境微生物学・生態学分野で先導的な成果をあげたと言える。