2018 Fiscal Year Final Research Report
Elucidation of the Origin and co-evolution process of symbiosis between cnidarian animal and green algae
| Project/Area Number |
16K07465
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Evolutionary biology
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
舘田 英典 九州大学, 理学研究院, 教授 (70216985)
楠見 淳子 九州大学, 比較社会文化研究院, 准教授 (20510522)
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| Research Collaborator |
Miyokawa Ryou
Kanaya Hiroyuki
Tuda Takuya
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | symbiosis / cnidaria / green algae / Hydra / Chlorella / Chlorococcum / horizontal transmission |
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| Outline of Final Research Achievements |
We carried out experiments to exchange endosymbiotic chlorellae between two different strains of green hydra which has established stable symbiotic relation between chlorella so long period. By analyzing the change in the trait and gene expression pattern of the host hydra by the exchange, it was clarified the specificity of the combination of host/symbiont.
Particular strain (J10) of hydra in the early state of symbiosis with chlorococcum is known only from Japan. We clarified that the chlorococci can escape from endodermal epithelial cells of host J10 strain hydra to the environmental water and can transmit horizontally to some other strain of non-symbiotic hydra. In particular strain of vulgaris geroup hydra (105 & SW strain), the transmitted chlorococci have established stable symbiotic relation with the host hydra. Then, we analyzied the change in the trait and gene expression pattern of the host hydra (105 statin) by the symbiosis with the horizontally transmitted chlorococci.
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| Free Research Field |
動物学・発生生物学・進化生物学
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| Academic Significance and Societal Importance of the Research Achievements |
グリーンヒドラとクロレラの共生関係は、緑藻と刺胞動物の共生のモデル系として古くから研究されてきていた。その起源の古さから、宿主のヒドラと共生クロレラの共進化や宿主/共生体の組み合わせ特異性が推測される。本研究において、共生クロレラを入れ換える実験系を確立し、解析を進めたことは共生の研究を一段階進めたという意義がある。
また、日本特産のクロロコッカムと共生の初期状態にあるヒドラ（J10系統）を用いて共生体の水平伝播が起こることを明らかにし、緑藻と共生をしていなかったヒドラが新しくクロロコッカムを共生させるときの形質と遺伝子発現の変化を解析したことは、共生の初期状態の研究の先駆けとなる。
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