How did plants requiring symbiotic fungi colonize oceanic islands?

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K06306
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Saga University
• Principal Investigator: Ogura-Tsujita Yuki 佐賀大学, 農学部, 准教授 (80522523)
• Co-Investigator(Kenkyū-buntansha): 遊川 知久 独立行政法人国立科学博物館, 植物研究部, グループ長 (50280524)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 菌根共生 / 海洋島 / ラン科植物 / 種子発芽

Outline of Final Research Achievements

Orchids require orchid mycorrhizal fungi (OMF) to germinate, and thus OMF associations play a key role in the expansion of orchid distributions. Geodorum densiflorum is widely distributed in tropical and sub-tropical Asia and Oceania. In Japan, this species was distributed in the Ryukyu Islands, but has recently been found in the Bonin Islands. We compared the OMF community of G. densiflorum between Ryukyu and Bonin Islands populations for understanding the mycorrhizal association involved in the recent expansion to the Bonin Islands. The common OMF fungi, Tulasnellaceae, were dominant in both islands. Phylogenetic analysis revealed that main fungal partners showed world-wide distributions. These results suggest that such wide distributing fungi allow the expansion of G. densiflorum to the Bonin Islands.

Free Research Field

植物学、系統分類

Academic Significance and Societal Importance of the Research Achievements

海洋島では風や波、鳥などで偶然運ばれた種で生物相が形成され、独自の生態系が見られる。植物が海洋島へ進出する戦略は、これまで風や動物による種子散布様式が着目されてきた。しかし、生物間相互作用も重要な定着因子となっている可能性がある。本研究は、特定の共生パートナーが定着に必須である植物が、海洋島への定着を成し得たメカニズムを明らかにし、海洋島の生物相形成の理解に大きく貢献した。