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. 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