Species and functions of rare actinomycetes in the post-Koch ecosystem

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: 19H05685
• 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: Ohnishi Yasuo 東京大学, 大学院農学生命科学研究科(農学部), 教授 (90292789)
• Co-Investigator(Kenkyū-buntansha): 稲橋 佑起 北里大学, 感染制御科学府, 准教授 (70645522) ; 松本 厚子 北里大学, 感染制御科学府, 准教授 (20300759)
• Project Period (FY): 2019-06-28 – 2024-03-31
• Keywords: 希少放線菌 / 菌株単離 / 二次代謝 / 生合成酵素 / 形態分化 / 遺伝子発現制御 / Actinoplanes / Sporichthya

Outline of Final Research Achievements

We developed a method for isolating rare actinomycetes using microculture arrays, including a co-culture system. Eight hundred and sixty-eight strains of rare actinomycetes were isolated, including 124 strains with high novelty, mainly using a modified conventional method. The genome sequences of six isolates were determined and used for genome mining. Twenty-nine isolates were subjected to PC screening and three novel compounds were identified. The biosynthetic pathways of seven actinomycete secondary metabolites were elucidated, and many enzymes that catalyze novel reactions were identified. We elucidated many of the molecular bases for the unique morphological and physiological characteristics exhibited by the model rare actinomycete Actinoplanes missouriensis. We also initiated a new study on rare actinomycetes in the genus Sporichthya.

Free Research Field

微生物学

Academic Significance and Societal Importance of the Research Achievements

環境中には未分離の希少放線菌がたくさん存在することが示された。これらの希少放線菌の生態系での機能に迫ることはできなかったが、新規化合物を生産する能力があることが化合物スクリーニングやゲノム配列解析によって明らかにされ、希少放線菌の生物活性物質（クスリになる化合物）の供給源としての重要性があらためて示された。一方、二次代謝産物生合成にはこれまで知られていない酵素反応が使われていることがあらためて示されたが、微生物を用いた有用物質生産への応用が期待できる。希少放線菌における細胞分化の巧妙な仕組みが明らかになったことも含めて、一連の研究により、微生物機能の多様性の一端を明らかにすることができた。