Functionally and geographical survey of phytotoxic pigment produced by non-photosynthetic organisms

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K19303
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 45:Biology at organismal to population levels and anthropology, and related fields
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: Tanifuji Goro 独立行政法人国立科学博物館, 動物研究部, 研究主幹 (70438480)
• Co-Investigator(Kenkyū-buntansha): 中山 卓郎 筑波大学, 計算科学研究センター, 助教 (70583508)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 非光合成葉緑体 / 光毒性色素 / メタゲノミクス

Outline of Final Research Achievements

We investigated the divergence and function of phototoxic pigments in non-photosynthetic organisms through a combination of metagenomics and culture experiments. In the culture experiments, we detected differential gene expression patterns depending on the light conditions. We found more expression variation in functionally unknown genes than in functionally known genes, suggesting the need for a more physiological approach. In the metagenomics approach, we conducted sampling twice a year, in summer and winter, for two years at various points in the freshwater aquatic plant section of a botanical garden in Tsukuba. The results showed that microbial flora differed depending on the season and location, even within the same water system. Additionally, previously unknown lineages of cyanobacteria were found in the eukaryotic-sized cell fraction, suggesting a symbiotic habitat for these cyanobacteria.

Free Research Field

微生物学、比較ゲノム学、進化学

Academic Significance and Societal Importance of the Research Achievements

クロロフィルは地球上に最も豊富に存在する色素である一方、光合成以外の機能についてはあまり考慮されていない。本研究では、海水域では沿岸部・外洋、淡水域では植物園・自然園内の各エリアの水サンプルを採集することで、疑似的に一般的な水環境を網羅的にサンプリングした。それらのエリアで非光合成葉緑体をもつ生物の多様性を解明し、環境中の存在量を推定した。今後のクロロフィルの光合成以外の機能に着目した研究により、進化多様性だけではなく生化学・生理学・生態学的な研究、および応用分野でも波及効果が期待される。