Heritable variation in bleaching responses and its functional genomic basis in reef-building corals (Orbicella faveolata)
Heritable variation in bleaching responses and its functional genomic basis in reef-building corals (Orbicella faveolata)
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DOI：
10.1111/mec.15081
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发表时间：
2019-05-01
影响因子：
4.9
通讯作者：
Meyer, Eli
中科院分区：
文献类型：
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作者：
Dziedzic, Katherine E.;Elder, Holland;Meyer, Eli
造礁珊瑚对不断上升的海洋温度高度敏感，珊瑚和它们所支持的生态系统要在不断变化的海洋条件下持续生存，就需要进行大量的适应。在一些珊瑚的幼虫阶段已经测量了可能支持适应性反应的遗传变异，但这些估计仍然无法用于成年珊瑚，而且这种变异的功能基础仍然不清楚。在这项研究中，我们重点研究了加勒比地区主要的珊瑚礁建造者Orbicella faveolata的适应潜力。我们对从巴拿马博卡斯德尔托罗自然种群中收集的珊瑚进行了热应激实验，并使用多位点SNP基因型来估计样本之间的遗传相关性。这使我们能够估计漂白反应变异的狭义遗传力，揭示这些反应的变异是高度可遗传的（h(2) = 0.58）。这表明该地区黄叶青属自然种群对变暖的适应性反应具有很大的潜力。我们使用基因组学和转录组学方法进一步研究了这种变异的功能基础。我们使用公开的遗传连锁图谱和基因组组装来绘制与漂白反应相关的标记，确定了12个与漂白反应变异相关的标记。我们还分析了具有不同漂白表型的珊瑚的基因表达，揭示了耐热珊瑚和热敏感珊瑚之间转录胁迫反应的实质性差异。总之，我们的发现有助于越来越多的证据表明，珊瑚自然种群在热应激反应中具有遗传变异，这可能潜在地支持对海洋温度上升的适应性反应。
Reef-building corals are highly sensitive to rising ocean temperatures, and substantial adaptation will be required for corals and the ecosystems they support to persist in changing ocean conditions. Genetic variation that might support adaptive responses has been measured in larval stages of some corals, but these estimates remain unavailable for adult corals and the functional basis of this variation remains unclear. In this study, we focused on the potential for adaptation in Orbicella faveolata, a dominant reef-builder in the Caribbean. We conducted thermal stress experiments using corals collected from natural populations in Bocas del Toro, Panama, and used multilocus SNP genotypes to estimate genetic relatedness among samples. This allowed us to estimate narrow-sense heritability of variation in bleaching responses, revealing that variation in these responses was highly heritable (h(2) = 0.58). This suggests substantial potential for adaptive responses to warming by natural populations of O. faveolata in this region. We further investigated the functional basis for this variation using genomic and transcriptomic approaches. We used a publicly available genetic linkage map and genome assembly to map markers associated with bleaching responses, identifying twelve markers associated with variation in bleaching responses. We also profiled gene expression in corals with contrasting bleaching phenotypes, uncovering substantial differences in transcriptional stress responses between heat-tolerant and heat-susceptible corals. Together, our findings contribute to the growing body of evidence that natural populations of corals possess genetic variation in thermal stress responses that may potentially support adaptive responses to rising ocean temperatures.