Transcriptional rearrangements associated with thermal stress and preadaptation in Baikal whitefish (Coregonus baicalensis). Transcriptional rearrangements associated with thermal stress and preadaptation in Baikal whitefish (Coregonus baicalensis)

In this work, we describe the transcriptional profiles of adapted and non-adapted one-month-old Baikal whitefish juveniles after heat shock exposure. Preadapted fish were exposed to a repeated thermal rise of 6 °C above control temperature every 3 days throughout embryonic development. One month after hatching, preadapted and non-adapted larvae were either maintained at control temperatures (12 °C) or exposed to an acute thermal stress (TS) of 12 °C above control temperature. The information on transcriptional profiles will contribute to further understanding of the mechanisms of adaptation of whitefish to the environment. Overall design: To study the effects of temperature stress, a transcriptomic analysis of adapted and non-adapted fish was conducted. For these purposes, the fish were divided into 4 groups: 1) a1_C_P Preadapted Control (C_P) in the temperature experiment on Baikal whitefish (Coregonus baicalensis) larvae: eggs adaptation at 30 days after fertilization (two times a week, increased temperature by 6 °C over the control of 3–3.5 °C, then lowering it to baseline values). Preconditioning training lasted for three months in total. In one month after adaptation, the larvae were sampled. 2) a2_AcS_P Preadapted Treatment (AcS_P) in the temperature experiment on Baikal whitefish (Coregonus baicalensis) larvae: eggs adaptation at 30 days after fertilization (two times a week, increased temperature by 6 °C over the control of 3–3.5 °C, then lowering it to baseline values). Preconditioning training lasted for three months in total. In one month after adaptation, larvae were exposed to "acute stress" up to 24 °C for two hours over the control of 12 °C, and sampled. 3) a3_AcS_N Non-adapted Treatment (AcS_NP) in the temperature experiment on Baikal whitefish (Coregonus baicalensis) larvae: One-month-old non-adaptated larvae were exposed to "acute stress" up to 24 °C for two hours over the control of 12 °C, and sampled. 4) a4_C_N Non-adapted Control (C_NP) in the temperature experiment on Baikal whitefish (Coregonus baicalensis) larvae: The temperature in the "control" aquariums remained constant at 12 °C throughout the experiment. One-month-old non-adaptated larvae were sampled. Grant ID No.: RSF 23-24-00644 (https://rscf.ru/project/23-24-00644/) Grant title: Biomarkers of temperature stress and indicators of the well-being of whitefish in the natural environment and in aquaculture for the further use of these biomarkers for monitoring work Funding source: Russian Science Foundation

本研究描述了经热激处理后的适应型与非适应型一月龄贝加尔白鲑（Coregonus baicalensis）幼鱼的转录谱（transcriptional profiles）。预适应组幼鱼在整个胚胎发育期间，每3天接受一次较对照温度升高6℃的热刺激。孵化后1个月，将预适应组与非适应组仔鱼分别置于对照温度（12℃）下饲养，或接受较对照温度升高12℃的急性热应激（acute thermal stress, TS）处理。该转录谱数据将有助于进一步阐明白鲑对环境的适应机制。

整体实验设计：
为探究温度应激的影响，本研究对适应型与非适应型贝加尔白鲑幼鱼开展了转录组分析。实验共分为4组：
1) a1_C_P 预适应对照组（C_P）：该组鱼卵于受精后30天开始进行预适应处理（每周2次，较3~3.5℃的对照温度升高6℃后回落至基线温度），整个预适应周期总计3个月。预适应结束1个月后，采集仔鱼样本。
2) a2_AcS_P 预适应应激组（AcS_P）：该组鱼卵同样于受精后30天开始预适应处理（每周2次，较3~3.5℃的对照温度升高6℃后回落至基线温度），预适应周期总计3个月。预适应结束1个月后，将仔鱼置于较12℃对照升高12℃的24℃环境中接受2小时急性应激处理，随后采集样本。
3) a3_AcS_N 非适应应激组（AcS_NP）：取1月龄未经过预适应的仔鱼，置于较12℃对照升高12℃的24℃环境中接受2小时急性应激处理后采集样本。
4) a4_C_N 非适应对照组（C_NP）：实验期间对照组水族箱温度恒定维持在12℃，取1月龄未经过预适应的仔鱼作为样本。

资助编号：俄罗斯科学基金会（Russian Science Foundation, RSF）23-24-00644（https://rscf.ru/project/23-24-00644/）
资助项目名称：自然环境与水产养殖场景下白鲑热应激生物标志物及健康状态指标，以供后续监测工作使用
资助方：俄罗斯科学基金会