Homologs of the green fluorescent protein (GFP) are a prevalent group of host pigments responsible for the green, red and purple-blue colours of many reef-building corals. They have been suggested to contribute to the striking coloration changes of different corals species in response to wounding and infestation with epibionts/parasites. In order to elucidate the physiological processes underlying the potentially disease-related colour changes, we have analysed spatial and temporal expression patterns of GFP-like proteins and other biomarkers in corals from the Red Sea, the Arabian/Persian Gulf and Fiji both in their natural habitat and under specific laboratory conditions. The expression of distinct GFP-like proteins and the growth marker proliferating cell nuclear antigen was upregulated in growing branch tips and margins of healthy coral colonies as well as in disturbed colony parts. Furthermore, phenoloxidase activity increased in these proliferating tissues. It is thus demonstrated that locally accelerated growth is part of the innate immune response and repair mechanisms in reef-building corals and, moreover, these processes can be detected utilizing the excellent biomarker properties of GFP-like proteins. Finally, the results of this work suggest an additional vulnerability of corals in predicted future scenarios of increased ocean acidification, warming and eutrophication that are anticipated to reduce coral growth capacity.
Bibliographical noteFunding Information:
Acknowledgments The study was funded by NERC (NE/I01683X/1 & NE/I012648/1 to JW; studentship to EGS), DFG (Wi1990/2-1 to JW) and ASSEMBLE (to JW & DT). Our appreciation is extended to A. Al-Hemeri of the UAE Federal Environment Agency and A. Al-Cibahy of the Environment Agency of Abu Dhabi for provision of CITES export permits (No. 09FEA555) for UAE corals. We are grateful to staff and students of Interuniversity Institute for Marine Science (Eilat) for field work support and to Dr. Chris Hauton (NOCS) for discussions about the phenoloxidase assays. We acknowledge Tropical Marine Centre (London, UK) and Tropic Marine (Wartenberg, Germany) for sponsoring of the Coral Reef Laboratory at NOCS.
- Climate change
- Coral bleaching
- Coral disease
- Coral parasite
- Green fluorescent protein (GFP)
- Immune response
ASJC Scopus subject areas
- Aquatic Science