Green fluorescence from cnidarian hosts attracts symbiotic algae

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14814
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Ecology/Environment
• Research Institution: National Institute for Basic Biology
• Principal Investigator: Aihara Yusuke 基礎生物学研究所, 環境光生物学研究部門, NIBBリサーチフェロー (40636891)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: サンゴ / 褐虫藻 / GFP / 走光性 / 共生

Outline of Final Research Achievements

Reef-building corals possess the endogenous green fluorescence proteins (GFPs) that emit green fluoresce on exposure to blue light. Although GFPs found in cnidarians have been proposed to function as photoprotective agents, this does not explain why deep-sea cnidarians living in continuous dark environments still possess GFPs. Here, we show that corals attract free living Symbiodinium by their endogenous GFP-associated fluorescence. Symbiodinium showed positive and negative phototaxis mostly toward strong blue and weak green light, respectively. Attraction of Symbiodinium by green fluorescence was observed using both a live coral fragment and an artificial green-fluorescence dye but only under blue light i.e. the wavelength that induces green florescence. We also show that traps painted with a green fluorescence dye captured Symbiodinium in the field. This study illustrates that GFPs in corals function as ecological signal to invite potential symbionts in underwater blue environments.

Free Research Field

光生理学