Thermal fluctuations affect the transcriptome through mechanisms independent of average temperature

Terrestrial ectotherms are challenged by variation in both mean and variance of temperature. Phenotypic plasticity (thermal acclimation) might mitigate adverse effects, however, we lack a fundamental understanding of the molecular mechanisms of thermal acclimation and how they are affected by fluctuating temperature. Here we investigated the effect of thermal acclimation in Drosophila melanogaster on critical thermal maxima (CTmax) and associated global gene expression profiles as induced by two constant and two ecologically relevant (non-stressful) diurnally fluctuating temperature regimes. Both mean and fluctuation of temperature contributed to thermal acclimation and affected the transcriptome. The transcriptomic response to mean temperatures comprised modification of a major part of the transcriptome, while the response to fluctuations affected a much smaller set of genes, which was highly independent of both the response to a change in mean temperature and to the classic heat shock...

陆生变温动物面临着温度均值与方差双重变化的挑战。表型可塑性（热适应，thermal acclimation）或许能缓解不利影响，但我们对热适应的分子机制及其如何受波动温度影响仍缺乏基础认知。本研究探究了黑腹果蝇（Drosophila melanogaster）中热适应对临界热最大值（CTmax）及相关全局基因表达谱的影响——这些影响由两种恒定温度模式和两种生态相关（非应激）的昼夜波动温度模式诱导产生。温度的均值与波动均参与热适应过程并影响转录组。对均值温度的转录组响应涉及转录组大部分区域的修饰，而对波动温度的响应仅影响少量基因，且该响应与对均值温度变化的响应及经典热休克反应高度独立……