Environmentally regulated genes as basis for coral reef resilience

环境调节基因作为珊瑚礁恢复力的基础

• 批准号: NE/I01683X/1
• 负责人: Joerg Wiedenmann
• 金额: $ 4.57万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI01683X%2F1
• 关键词: Environmentally; regulated; genes; basis; coral

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.

热带珊瑚礁是海洋生物多样性最重要的中心之一，提供了宝贵的生态系统服务，因为数百万人在经济上依赖珊瑚礁及其生物。全球变暖和海洋酸化等多种自然和人为压力因素可能会导致本世纪内珊瑚礁急剧减少。由于人为排放的二氧化碳增加，特别是海水温度上升和 pH 值下降，预计海洋生物面临的压力会越来越大。珊瑚礁的未来在很大程度上取决于石珊瑚适应这些环境条件变化的能力。它们的适应潜力取决于它们进化新性状或调节现有基因表达的能力。然而，当前的气候变化发生在前所未有的短时间内，阻碍了珊瑚礁通过进化新特征来适应。因此，它们的主要生存策略可能在于其基因组中已经编码的表型可塑性。例如，某些基因响应变化的环境条件而上调，可以在个体基因水平或群体水平上通过正向选择表现出表达水平增加的基因型来实现。由于预适应过程和/或在极端环境条件下的某些生态位中的正选择，群体中可能存在具有偏差表达水平的个体。因此，造礁珊瑚未来的可预测性在很大程度上取决于对环境调节基因功能的了解，而这一方面尚未得到广泛研究。因此，我们着手探索造血珊瑚环境控制基因的基因组基础。我们确定珊瑚鹿角珊瑚及其编码红色荧光蛋白 amFP597 (RFP) 的基因作为研究环境控制基因的调节可塑性的理想模型系统。 RFP 被认为具有光保护功能，优化浅水中的生长。我们发现 RFP 编码基因受到光的强烈上调。不同颜色的千花珊瑚对光照气候的变化表现出相同的反应。然而，我们确定了变体之间在转录物绝对量方面存在显着差异：例如，与绿色变体相比，红色变体的光照组织和阴影组织中的 RFP 转录物浓度高出五倍多。这些结果意味着保护性珊瑚蛋白的组织浓度不仅取决于编码基因的环境控制，还取决于该基因对刺激的形态类型特异性最大反应。颜色变形之间转录水平的变异性似乎在遗传上是固定的，因为物种内的颜色差异在相同的环境条件下得以保留。因此，这一引人注目的调节可塑性案例为研究环境调节基因的基因组基础提供了理想的条件。我们将评估最有可能解释所观察到的 RFP 转录水平差异的两种遗传情况：A) 颜色变形拥有 RFP 编码基因的不同变体，其序列发生改变，例如在基因调控区（启动子）中。 B) RFP 编码基因在颜色变形中以不同的拷贝数存在。为了解决千花珊瑚中实现了哪种情况的问题，我们将对绿色、棕色和红色变体中的 RFP 编码基因进行深入分析。所需的珊瑚已在 NOCS 珊瑚实验室的实验水族馆系统中保存和繁殖。我们将应用一套先进的分子生物学技术来获得对珊瑚礁基因调控策略前所未有的见解。

项目成果

Locally accelerated growth is part of the innate immune response and repair mechanisms in reef-building corals as detected by green fluorescent protein (GFP)-like pigments

局部加速生长是造礁珊瑚先天免疫反应和修复机制的一部分，可通过绿色荧光蛋白 (GFP) 类色素检测到

• DOI: http://dx.10.1007/s00338-012-0926-8
• 发表时间: 2012
• 期刊: Coral Reefs
• 影响因子: 3.5
• 作者: D'Angelo C

Spectral Diversity and Regulation of Coral Fluorescence in a Mesophotic Reef Habitat in the Red Sea.

红海中光珊瑚礁栖息地珊瑚荧光的光谱多样性和调节。

• DOI: http://dx.10.1371/journal.pone.0128697
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Eyal G

Critical research needs for identifying future changes in Gulf coral reef ecosystems.

确定海湾珊瑚礁生态系统未来变化的关键研究需求。

• DOI: http://dx.10.1016/j.marpolbul.2013.02.038
• 发表时间: 2013
• 期刊: Marine pollution bulletin
• 影响因子: 5.8
• 作者: Feary DA

Fluorescent protein-mediated colour polymorphism in reef corals: multicopy genes extend the adaptation/acclimatization potential to variable light environments.

珊瑚礁珊瑚中荧光蛋白介导的颜色多态性：多拷贝基因扩展了对可变光环境的适应/驯化潜力。

• DOI: http://dx.10.1111/mec.13041
• 发表时间: 2015
• 期刊: Molecular ecology
• 影响因子: 4.9
• 作者: Gittins JR

An experimental mesocosm for long-term studies of reef corals

用于珊瑚礁长期研究的实验中生态系统

• DOI: http://dx.10.1017/s0025315411001883
• 发表时间: 2011
• 期刊: Journal of the Marine Biological Association of the United Kingdom
• 影响因子: 1.2
• 作者: D'angelo C