Insights into coral bleaching under heat stress from analysis of gene expression in a sea anemone model system
Insights into coral bleaching under heat stress from analysis of gene expression in a sea anemone model system
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DOI：
10.1073/pnas.2015737117
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发表时间：
2020-11-17
影响因子：
11.1
通讯作者：
Pringle, John R.
中科院分区：
文献类型：
--
作者：
Cleves, Phillip A.;Krediet, Cory J.;Pringle, John R.
在热压力下失去内共生藻类（“漂白”）已成为世界各地造礁珊瑚的一个主要问题。为了确定可能参与触发或执行漂白或保护珊瑚免受漂白的基因，我们使用RNAseq分析了珊瑚亲戚海葵Aiptasia在热应激期间的基因表达变化。我们鉴定了超过500个基因，这些基因在温度升高时表现出快速和广泛的上调。这些基因分为两类。在这两个集群中，大多数基因在共生和非共生海葵中表现出相似的表达模式，这表明这种早期应激反应在很大程度上独立于共生。聚类I高度富集了参与先天免疫和细胞凋亡的基因，并且大多数转录水平在首次检测到漂白之前数小时恢复到基线，这引起了人们对它们在这一过程中可能作用的怀疑。簇II高度富集了参与蛋白质折叠的基因，并且大多数转录水平更缓慢地恢复到基线，因此促进或防止漂白的作用似乎是合理的。簇I和簇II中的许多基因似乎分别是转录因子NF κ B和HSF 1的靶标。我们还研究了337个基因的行为，这些基因在没有压力的情况下在共生海葵中的表达水平比在非共生海葵中的表达水平高得多，这表明它们对共生很重要。出乎意料的是，在许多情况下，这些表达水平在漂白本身很明显之前就急剧下降，这表明共生支持基因表达的丧失可能与引发漂白有关。
Loss of endosymbiotic algae ("bleaching") under heat stress has become a major problem for reef-building corals worldwide. To identify genes that might be involved in triggering or executing bleaching, or in protecting corals from it, we used RNAseq to an-alyze gene-expression changes during heat stress in a coral relative, the sea anemone Aiptasia. We identified >500 genes that showed rapid and extensive up-regulation upon temperature increase. These genes fell into two clusters. In both clusters, most genes showed similar expression patterns in symbiotic and aposymbiotic anemones, suggesting that this early stress response is largely independent of the symbiosis. Cluster I was highly enriched for genes involved in innate immunity and apoptosis, and most transcript levels returned to baseline many hours before bleaching was first detected, raising doubts about their possible roles in this process. Cluster II was highly enriched for genes involved in protein folding, and most transcript levels returned more slowly to baseline, so that roles in either promoting or preventing bleaching seem plausible. Many of the genes in clusters I and II appear to be targets of the transcription factors NF kappa B and HSF1, respectively. We also examined the behavior of 337 genes whose much higher levels of expression in symbiotic than aposymbiotic anemones in the absence of stress suggest that they are important for the symbiosis. Unexpectedly, in many cases, these expression levels declined precipitously long before bleaching itself was evident, suggesting that loss of expression of symbiosis-supporting genes may be involved in triggering bleaching.