Information about the genomic processes underlying responses to temperature changes is still limited in non‐model marine invertebrates. In this sense, transcriptomic analyses can help to identify genes potentially related to thermal responses. We here investigated, via RNA‐seq, whole‐transcriptomic responses to increased and decreased temperatures in a thermophilous keystone sea urchin, Arbacia lixula, whose populations are increasing in the Mediterranean. This species is a key driver of benthic communities’ structure due to its grazing activity. We found a strong response to experimentally induced cold temperature (7°C), with 1,181 differentially expressed transcripts relative to the control condition (13°C), compared to only 179 in the warm (22°C) treatment. A total of 84 (cold treatment) and three (warm treatment) gene ontology terms were linked to the differentially expressed transcripts. At 7°C the expression of genes encoding different heat shock proteins (HSPs) was upregulated, together with apoptotic suppressor genes (e.g., Bcl2), genes involved in the infection response and/or pathogen‐recognition (e.g., echinoidin) and ATP‐associated genes, while protein biosynthesis and DNA replication pathways were downregulated. At 22°C neither HSPs induction nor activation of the previously mentioned pathways were detected, with the exception of some apoptotic‐related activities that were upregulated. Our results suggest a strong transcriptional response associated with low temperatures, and support the idea of low water temperature being a major limitation for A. lixula expansion across deep Mediterranean and northern Atlantic waters.

中文翻译：

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享受温暖的地中海：底栖群落中嗜热基石物种温度变化的转录组学响应。

在非模型海洋无脊椎动物中，有关温度变化响应的基因组过程的信息仍然有限。从这个意义上讲，转录组分析可以帮助识别与热反应潜在相关的基因。我们在这里通过RNA序列研究了嗜热基石海胆Arbacia lixula对温度升高和降低的全转录组反应，其人口在地中海不断增加。由于其放牧活动，该物种是底栖生物群落结构的关键驱动力。我们发现对实验诱导的低温（7°C）有强烈反应，相对于对照条件（13°C）有1,181个差异表达的转录本，而温热（22°C）处理中只有179个。共有84个（冷处理）和三个（暖处理）基因本体术语与差异表达的转录本相关。在7°C，编码不同热休克蛋白（HSP）的基因的表达与凋亡抑制基因（例如Bcl2）一起上调，与感染反应和/或病原体识别有关的基因（例如棘孢菌素）和ATP相关基因，而蛋白质的生物合成和DNA复制途径被下调。在22°C下，既没有检测到HSPs的诱导也没有检测到上述途径的激活，除了一些与凋亡相关的活动被上调外。我们的研究结果表明与低温相关的强烈转录反应，并支持低水温是螺旋藻在地中海深水和北大西洋水域扩展的主要限制。