Diversity of the bacteria with symbiotic relationships to marine microeukaryotes

2023 Fiscal Year Final Research Report

• Project/Area Number: 18KK0203
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: INAGAKI Yuji 筑波大学, 計算科学研究センター, 教授 (50387958)
• Co-Investigator(Kenkyū-buntansha): 石谷 佳之 国立研究開発法人海洋研究開発機構, 超先鋭研究開発部門(超先鋭研究プログラム), 特任研究員 (60772043) ; 中山 卓郎 筑波大学, 計算科学研究センター, 助教 (70583508) ; 矢吹 彬憲 国立研究開発法人海洋研究開発機構, 地球環境部門(海洋生物環境影響研究センター), グループリーダー (20711104)
• Project Period (FY): 2018-10-09 – 2024-03-31
• Keywords: 原生生物－細菌共生系 / 細胞内共生 / 生物多様性 / 海洋生態系 / 生態地理

Outline of Final Research Achievements

When assessing bacterial diversity in the ocean using metabarcoding (MB) data, many MB sequences do not show any sequence similarities from previously known species that have been studied by the standard method incorporating laboratory culture. Since the ocean is home to a wide variety of bacteria, MB sequences are thought to encompass the bacteria new to science because they have never been cultured or difficult to culture in the laboratory. However, due to potential difficulties in experiments, even the bacterial diversity in the ocean predicted by MB methods does not adequately cover the true diversity of those with symbiotic relationships with eukaryotes. In this study, we aimed to sequence the genomes of bacteria with symbiotic relationships with a wide range of marine microeukaryotes. In particular, we succeeded in sequencing the genomes of the cyanobacteria symbiotically associated with dinoflagellates.

Free Research Field

微生物分子進化

Academic Significance and Societal Importance of the Research Achievements

ディノフィシス目渦鞭毛藻の一種であるCitharistes regiusと共生するシアノバクテリアの全ゲノム配列決定に成功した。この共生性シアノバクテリア（CregCyn）は海洋性ピコシアノバクテリア系統に属し、Citharistesに近縁な別の渦鞭毛藻Ornithocercus magnificusの共生性シアノバクテリア（OmCyn）と近縁であったが、それぞれ独立に共生関係を確立したと考えられる。本研究は、渦鞭毛藻とシアノバクテリアの共生の複雑な歴史と、海洋ピコシアノバクテリアのゲノム多様性の理解に貢献する。