Data from: Variation in the transcriptional response of threatened coral larvae to elevated temperatures

Coral populations have declined worldwide largely due to increased sea surface temperatures. Recovery of coral populations depends in part upon larval recruitment. Many corals reproduce during the warmest time of year when further increases in temperature can lead to low fertilization rates of eggs and high larval mortality. Microarray experiments were designed to capture and assess variability in the thermal stress responses of Acropora palmata larvae from Puerto Rico. Transcription profiles showed a striking acceleration of normal developmental gene expression patterns with increased temperature. The transcriptional response to heat suggested rapid depletion of larval energy stores via peroxisomal lipid oxidation and included key enzymes that indicated the activation of the glyoxylate cycle. High temperature also resulted in expression differences in key developmental signalling genes including the conserved WNT pathway that is critical for pattern formation and tissue differentiation in developing embryos. Expression of these and other important developmental and thermal stress genes such as ferritin, heat shock proteins, cytoskeletal components, cell adhesion and autophagy proteins also varied among larvae derived from different parent colonies. Disruption of normal developmental and metabolic processes will have negative impacts on larval survival and dispersal as temperatures rise. However, it appears that variation in larval response to high temperature remains despite the dramatic population declines. Further research is needed to determine whether this variation is heritable or attributable to maternal effects.

全球范围内的珊瑚种群数量大幅下降，主要归因于海表温度升高。珊瑚种群的恢复在一定程度上依赖于幼体补充（larval recruitment）。许多珊瑚在一年中最温暖的时段繁殖，此时温度的进一步升高会导致卵子受精率降低以及幼体死亡率升高。本研究设计了微阵列（Microarray）实验，以捕捉并评估来自波多黎各的大鹿角珊瑚（Acropora palmata）幼体的热应激响应差异。转录表达谱显示，随着温度升高，正常发育基因的表达模式出现了显著加速。对热刺激的转录响应表明，幼体的能量储备通过过氧化物酶体脂质氧化被快速消耗，且该响应包含了指示乙醛酸循环（glyoxylate cycle）激活的关键酶类。高温还导致了关键发育信号通路基因的表达差异，其中包括对胚胎发育过程中的模式形成与组织分化至关重要的保守WNT信号通路（WNT pathway）。来自不同亲本珊瑚株系的幼体，其上述基因以及铁蛋白（ferritin）、热休克蛋白（heat shock proteins）、细胞骨架成分、细胞黏附蛋白与自噬蛋白等其他重要发育相关基因和热应激基因的表达模式也存在差异。随着温度升高，正常发育与代谢过程的紊乱会对幼体的存活与扩散产生负面影响。然而，尽管珊瑚种群数量大幅下降，幼体对高温的响应差异依然存在。未来仍需开展进一步研究，以明确这种响应差异究竟是可遗传的，还是由母源效应（maternal effects）所导致的。