Raw data associated with Scheuffele et al. (2023): Daily thermal variability does not modify long-term gene expression relative to stable thermal environments: A case study of a tropical fish

Global warming is leading to an increase in the frequency and intensity of extreme weather events, magnifying the breadth of temperatures faced by ectotherms across days and seasons. Despite the importance and ecological relevance of diurnal thermal variability, the vast majority of knowledge on gene expression patterns and physiology stems from animals acclimated to constant temperatures or in the early stages of exposure to a new temperature regime. If heterothermal environments modulate responses differently from constant thermal environments, our existing capacity to forecast impacts of climate warming may be compromised. To address this knowledge gap, we acclimated barramundi (Lates calcarifer) to 23 °C, 29 °C (optimal), 35 °C and to thermal cycling conditions (23‐–35 °C daily with a mean of 29 °C) and sampled liver and white muscle tissue before acclimation and after 2 and 17 weeks of acclimation. NanoString nCounter technologies were used to measure expression of 20 genes related to metabolism, growth and maintenance of cellular homeostasis. Acclimation to cool and warm conditions caused predictable changes in whole-animal performance (metabolism and growth) and the underlying gene expression patterns. Acclimation to a cycling temperature regime did not change the molecular regulation of metabolism or growth compared with barramundi acclimated to constant 29 °C, nor did it cause any discernible effects on whole-animal performance. However, the heat shock response was higher in the former group, suggesting that barramundi under a daily temperature cycle have an increased need for cellular chaperoning to minimise detrimental effects of temperature on proteins. We conclude that the genetic regulation of metabolism and growth may be more dependent on the mean daily temperature than on the daily temperature range.

全球变暖正导致极端天气事件的发生频率与强度持续攀升，进一步扩大了变温动物（ectotherms）在每日及季节间所面临的温度跨度。尽管昼夜温度波动具有重要的生态意义，但目前有关基因表达模式与生理机能的绝大多数认知，均来自于适应恒定温度，或是刚暴露于新温度环境初期的受试生物。倘若异温环境与恒定热环境对生物响应的调控机制存在差异，那么我们现有预测气候变暖影响的能力或将大打折扣。为填补这一认知空白，本研究将澳洲肺鱼（barramundi，学名Lates calcarifer）分别驯化于23℃、29℃（最适温度）、35℃以及周期性温度波动环境（每日温度在23℃至35℃间波动，平均温度为29℃），并在驯化前、驯化2周及17周后采集其肝脏与白色肌肉组织样本。本研究采用NanoString nCounter技术，对20个与代谢、生长及细胞内稳态（cellular homeostasis）维持相关的基因的表达量进行检测。适应冷、热温度环境的受试个体，其整体生理机能（代谢与生长）及相关基因表达模式均出现了可预期的变化。与驯化于恒定29℃的澳洲肺鱼相比，驯化于周期性温度环境的个体，其代谢与生长的分子调控机制并未发生改变，同时其整体生理机能也未出现可观测的变化。但该周期性温度驯化组的热休克响应水平更高，这表明处于每日温度波动环境下的澳洲肺鱼，对细胞分子伴侣的需求有所提升，以尽可能降低温度对蛋白质的损害作用。本研究最终得出结论：代谢与生长的遗传调控机制，或许更多依赖于每日平均温度，而非每日温度波动幅度。