Anomalous heat waves are causing a major decline of hard corals around the world and threatening the persistence of coral reefs. There are, however, reefs that have been exposed to recurrent thermal stress over the years and whose corals appear to have been tolerant against heat. One of the mechanisms that could explain this phenomenon is local adaptation, but the underlying molecular mechanisms are poorly known. In this work, we applied a seascape genomics approach to study heat stress adaptation in three coral species of New Caledonia (southwestern Pacific) and to uncover the molecular actors potentially involved. We used remote sensing data to characterize the environmental trends across the reef system, and sampled corals living at the most contrasted sites. These samples underwent next generation sequencing to reveal single nucleotide polymorphisms (SNPs), frequencies of which were associated with heat stress gradients. As these SNPs might underpin an adaptive role, we characterized the functional roles of the genes located in their genomic region. In each of the studied species, we found heat stress‐associated SNPs located in proximity of genes involved in pathways well known to contribute to the cellular responses against heat, such as protein folding, oxidative stress homeostasis, inflammatory and apoptotic pathways, and DNA damage‐repair. In some cases, the same candidate molecular targets of heat stress adaptation recurred among species. Together, these results underline the relevance and the power of the seascape genomics approach for the discovery of adaptive traits that could allow corals to persist across wider thermal ranges.

中文翻译：

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海景基因组学揭示了三种珊瑚物种热应激适应的候选分子靶标

异常的热浪正在导致全世界硬珊瑚的大量减少，并威胁着珊瑚礁的持久性。但是，有些珊瑚礁多年来一直承受着反复的热应力作用，它们的珊瑚似乎耐热。可以解释这种现象的机制之一是局部适应性，但是潜在的分子机制却鲜为人知。在这项工作中，我们采用了一种海景基因组学方法来研究新喀里多尼亚（西南太平洋）的三种珊瑚物种的热应力适应性，并揭示潜在的分子作用因子。我们使用遥感数据来描述整个礁石系统的环境趋势，并对生活在对比度最高的地点的珊瑚进行了采样。这些样品进行了下一代测序，以揭示单核苷酸多态性（SNP），其频率与热应力梯度相关。由于这些SNP可能支撑适应性作用，因此我们对位于其基因组区域的基因的功能性作用进行了表征。在每个研究的物种中，我们发现与热应激相关的单核苷酸多态性位于基因的附近，这些基因参与了众所周知的有助于细胞抵抗热的反应，例如蛋白质折叠，氧化应激稳态，炎性和凋亡途径以及DNA损伤。 -修理。在某些情况下，物种之间会重复出现相同的候选热应激适应分子靶标。一起，