Characterizing environmental stress responses of aposymbiotic Astrangia poculata to divergent thermal challenges
Characterizing environmental stress responses of aposymbiotic Astrangia poculata to divergent thermal challenges
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DOI：
10.1111/mec.16108
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发表时间：
2021-08
影响因子：
4.9
通讯作者：
D. Wuitchik;A. Almanzar;Brooke Elizabeth Benson;S. Brennan;J. Chávez;M. Liesegang;J. Reavis;C. L. Reyes;M. Schniedewind;I. Trumble;S. Davies
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作者：
D. Wuitchik;A. Almanzar;Brooke Elizabeth Benson;S. Brennan;J. Chávez;M. Liesegang;J. Reavis;C. L. Reyes;M. Schniedewind;I. Trumble;S. Davies
人为的气候变化威胁着全球的珊瑚，高温和低温都会导致珊瑚白化。然而，珊瑚在宽热宽度上的应激反应仍未得到充分研究。在专性共生珊瑚中，解开共生对应激反应的作用是具有挑战性的，因为这种反应固有地与营养应激相结合。在这里，我们利用兼性共生珊瑚的非共生菌落，asstrangia poculata，它自然地与藻类共生或不与藻类共生，来研究在没有共生的情况下，广泛的热挑战如何影响珊瑚宿主。在两个独立的为期16天的普通花园实验（冷热挑战）中，从其北部范围的极限处收集了A. poculata，并进行了热挑战，并对食物刺激的行为反应和全基因组基因表达谱（TagSeq）进行了分析。这两种热挑战都导致了息肉延伸的显著减少。然而，与热胁迫相比，冷胁迫下差异表达基因（deg）的数量增加了5倍。尽管对冷挑战的总体反应更强，但热挑战之间的deg存在显着重叠。我们将这些反应与热带造礁珊瑚中先前确定的与环境应激反应（ESR）相关的基因模块进行了对比。冷挑战珊瑚表现出与更严重的压力一致的模式，而热挑战响应与较低强度的压力一致。鉴于这些反应是在非共生菌落中观察到的，许多先前在热带共生物种中涉及esr的基因可能代表了珊瑚宿主在共生或非共生状态下的应激反应。
Anthropogenic climate change threatens corals globally and both high and low temperatures are known to induce coral bleaching. However, coral stress responses across wide thermal breadths remain understudied. Disentangling the role of symbiosis on the stress response in obligately symbiotic corals is challenging because this response is inherently coupled with nutritional stress. Here, we leverage aposymbiotic colonies of the facultatively symbiotic coral, Astrangia poculata, which lives naturally with and without its algal symbionts, to examine how broad thermal challenges influence coral hosts in the absence of symbiosis. A. poculata were collected from their northern range limit and thermally challenged in two independent 16‐day common garden experiments (heat and cold challenge) and behavioural responses to food stimuli and genome‐wide gene expression profiling (TagSeq) were performed. Both thermal challenges elicited significant reductions in polyp extension. However, there were five times as many differentially expressed genes (DEGs) under cold challenge compared to heat challenge. Despite an overall stronger response to cold challenge, there was significant overlap in DEGs between thermal challenges. We contrasted these responses to a previously identified module of genes associated with the environmental stress response (ESR) in tropical reef‐building corals. Cold challenged corals exhibited a pattern consistent with more severe stressors while the heat challenge response was consistent with lower intensity stressors. Given that these responses were observed in aposymbiotic colonies, many genes previously implicated in ESRs in tropical symbiotic species may represent the coral host's stress response in or out of symbiosis.