Environmentally regulated genes as basis for coral reef resilience
Lead Research Organisation:
University of Southampton
Department Name: Sch of Ocean and Earth Science
Abstract
Tropical coral reefs are among the most important centres of marine biodiversity, providing invaluable ecosystem services as millions of people are economically dependent on the reef and its creatures. A multiplicity of natural and anthropogenic stressors such as global warming and ocean acidification might result in a dramatic loss of coral reefs within this century. Increasing stress for marine organisms is expected in response to the anthropogenic increase in CO2, especially to rising seawater temperatures and decreasing pH. The future of coral reefs is strongly dependent on the capability of scleractinian corals to adapt to these changes in environmental conditions. Their adaptation potential is defined by their capacity to evolve new traits or to regulate the expression of existing genes. However, current climate change happens over an unprecedented short period of time, preventing an adaptation of reef corals by evolution of new traits. Consequently, their main strategy for survival may lie in the phenotypic plasticity that is already encoded in their genome. Up-regulation of certain genes in response to changing environmental conditions, for instance, can be realized on the level of the individual gene or on the population level by the positive selection of genotypes which show increased expression levels. Individuals with deviating expression levels can be present in a population as result of preadaptation processes and / or by positive selection in certain ecological niches with extreme environmental conditions. Hence, predictability of the future of reef-building corals depends strongly on knowledge of the functioning of environmentally regulated genes, an aspect as yet largely unstudied. Therefore, we set out to explore the genomic basis of environmentally controlled genes in hermatypic corals. We identified the coral Acropora millepora and its gene encoding the red fluorescent protein amFP597 (RFP) as ideal model system to study the regulatory plasticity of environmentally controlled genes. The RFP is considered to fulfill a photoprotective function, optimizing growth in shallow waters. We found that the RFP-encoding gene is strongly up-regulated by light. It shows the same response to changes in the light climate in different colour morphs of A. millepora. However, we determined strong differences between the morphs regarding the absolute amount of transcripts: The RFP transcript concentration was, for instance, more than five-fold higher both in the light exposed and shaded tissue in the red morph compared to the green morph. These results imply that the tissue concentration of a protective coral protein depends not only on the environmental control of the encoding gene but also on the morphotype-specific maximal response of the gene to a stimulus. The variability in transcript levels among the colour morphs appears to be genetically fixed as colour differences within species are retained under identical environmental conditions. Therefore, this striking case of regulatory plasticity offers ideal conditions to study the genomic basis of environmentally regulated genes. We will evaluate two genetic scenarios most likely to explain the observed differences in the RFP transcript levels: A) The colour morphs possess different variants of the RFP-encoding gene with altered sequences, for instance, in the gene regulatory region (promoter). B) The RFP-encoding gene is present in different copy numbers among the colour morphs. To address the question which scenario is realised in A. millepora, we will perform an in-depth analysis of the RFP-encoding gene in the green, brown and red colour morphs. The required corals are already kept and propagated in the experimental aquarium system of the Coral Laboratory at NOCS. We will apply a suite of advanced molecular biological techniques to gain unprecedented insights in gene regulation strategies in reef corals.
People |
ORCID iD |
Joerg Wiedenmann (Principal Investigator) |
Publications
Smith EG
(2017)
Acclimatization of symbiotic corals to mesophotic light environments through wavelength transformation by fluorescent protein pigments.
in Proceedings. Biological sciences
D'angelo C
(2011)
An experimental mesocosm for long-term studies of reef corals
in Journal of the Marine Biological Association of the United Kingdom
Mallien C
(2017)
Conspicuous morphological differentiation without speciation in Anemonia viridis (Cnidaria, Actiniaria)
in Systematics and Biodiversity
Bollati E
(2020)
Corals display bright colours to fight bleaching
in TheScienceBreaker
Hume B
(2013)
Corals from the Persian/Arabian Gulf as models for thermotolerant reef-builders: prevalence of clade C3 Symbiodinium, host fluorescence and ex situ temperature tolerance.
in Marine pollution bulletin
Feary DA
(2013)
Critical research needs for identifying future changes in Gulf coral reef ecosystems.
in Marine pollution bulletin
Hartle-Mougiou K
(2011)
Diversity of zooxanthellae from corals and sea anemones after long-term aquarium culture
in Journal of the Marine Biological Association of the United Kingdom
Jung, Gregor
(2011)
Fluorescent Proteins I
Description | Climate change happens over an unprecedented short period of time, preventing an adaptation of reef corals by evolution of new traits. Consequently, their main strategy for survival may lie in the phenotypic plasticity that is already encoded in their genome. Hence, predictability of the future of coral reefs depends strongly on knowledge of the functioning of environmentally regulated genes. We set out to explore the genomic basis of environmentally controlled genes in hermatypic corals. All objectives were successfully achieved. |
Exploitation Route | Reef conservation; reef monitoring Our results clearly demonstrate that the GFP-like host pigments can be used as intrinsic markers of physiological processes and the overall health in corals. These findings will facilitate the development of non-invasive, fast and low cost methods to assess stress levels in coral reef communities in the field. |
Sectors | Education Environment |
URL | http://noc.ac.uk/corals |
Description | The findings from this research have allowed us to suggest novel strategies that corals utilise to increase their potential oto extend their distribution range along the steep light gradients of coral reefs and to inhabit more ecological niches. |
First Year Of Impact | 2014 |
Sector | Education,Environment,Leisure Activities, including Sports, Recreation and Tourism |
Description | Collaboration with Industry Partner |
Organisation | Tropical Marine Centre London |
Country | United Kingdom |
Sector | Private |
PI Contribution | Expert advice on coral fluorescence and effects of light on corals. |
Collaborator Contribution | Case funding for student ship and sponsorship of the outreach aquarium at NOCS. |
Impact | -PhD student projects -Contribution to outreach |
Start Year | 2011 |
Description | 2018 Gordon Research Conference "Photosensory Receptors and Signal Transduction" Lucca (Italy). |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | • 2018 Gordon Research Conference "Photosensory Receptors and Signal Transduction" Lucca (Italy). Invited presentations. |
Year(s) Of Engagement Activity | 2018 |
Description | 2018 Winterschool "Fluorescence markers for advanced microscopy" Les Houches (France). |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | 2018 Winterschool "Fluorescence markers for advanced microscopy" Les Houches (France). |
Year(s) Of Engagement Activity | 2018 |
Description | Coral Fluorescence Display at Southampton Boatshow 2015 |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Fluorescent coral display at Southampton Boatshow 2015, seen by ~20k visitors. |
Year(s) Of Engagement Activity | 2015 |
URL | http://aquaraylighting.co.uk/research-and-development/ |
Description | Dec. 2017 Organiser, Session "Nutrient Physiology and Ecology of Coral Reefs". European Coral Reef Symposium, Oxford, UK including Opening Presentation |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Dec. 2017 Organiser, Session "Nutrient Physiology and Ecology of Coral Reefs". European Coral Reef Symposium, Oxford, UK including Opening Presentation |
Year(s) Of Engagement Activity | 2017 |
Description | General interest publication: https://theconversation.com/coral-reefs-that-glow-bright-neon-during-bleaching-offer-hope-for-recovery-new-study-139048 |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Global access with high attention range. |
Year(s) Of Engagement Activity | 2020 |
URL | https://theconversation.com/coral-reefs-that-glow-bright-neon-during-bleaching-offer-hope-for-recove... |
Description | Genetic basis of colour diversity in coral reefs discovered |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | A press release prepared by the PI discusses the major findings of the research in coral colour, resulting in a wide interest in this topic and awareness of the urgency of conserving coral diversity. |
Year(s) Of Engagement Activity | 2015 |