Origins and distribution of coral-associated microorganisms in the environment: imported from land area?

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K15402
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Environmental agriculture(including landscape science)
• Research Institution: University of the Ryukyus
• Principal Investigator: Ito Michihiro 琉球大学, 熱帯生物圏研究センター, 助教 (80711473)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: サンゴ / サンゴ微生物叢 / 陸域起源微生物 / 海藻共存微生物 / 除草剤 / 除草剤分解微生物

Outline of Final Research Achievements

In this study, we examined the origins and distribution of microorganisms associated with corals in the environment, especially focusing on the potential effect of terrestrial microorganisms on coral microbiome and coral diseases. The microbiome of a reef building coral Montipora digitata inhabiting Nagazone reef, was analyzed and compared to those of sea water along the coastal area of Motobu town, Okinawa, which has three river mouths and a sewage treatment plant. The result was consistent with the hypothesis that a bacterial lineage inhabit both terrestrial and coral reef environment. The involvement of bacteria with coral disease was not clear. Furthermore, we found bacteria potentially associated with corals in a brown alga Cladosiphon okamuranus inhabiting the coastal area in Bise, Motobu town. This result suggests that coral-associated bacteria are distributed in taxonomically-different host species.

Free Research Field

微生物生態学

Academic Significance and Societal Importance of the Research Achievements

サンゴにはサンゴの健康維持に寄与する微生物や、サンゴの病気を引き起こす微生物が存在する。サンゴの病原菌の由来と分布の解明はサンゴ礁保全の一助となる。そこで本研究では、陸域起源の微生物がサンゴに害を与え得るとの仮説の検証を試みた。この検証の結果は判然としていないが、サンゴ礁に隣接する畑土壌より、サンゴの生育の阻害効果を有し、沖縄県で多用されている除草剤の分解微生物を見出すことができた。このような微生物の取得・機能解明と有効活用はサンゴ礁の保全に役立つ可能性がある。また、サンゴ病原菌と、その生育を抑える能力を有する可能性のある菌の、サンゴ礁内での棲み場所について新たな知見を得ることができた。