Bowen Lizabeth, von Biela Vanessa R, McCormick Stephen D, Regish Amy M, Waters Shannon C, Durbin-Johnson Blythe, Britton Monica, Settles Matthew L, Donnelly Daniel S, Laske Sarah M, Carey Michael P, Brown Randy J, Zimmerman Christian E
U.S. Geological Survey, Western Ecological Research Center, One Shields Avenue, Davis, CA, 95616, USA.
U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK, 99508, USA.
Conserv Physiol. 2020 Sep 11;8(1):coaa084. doi: 10.1093/conphys/coaa084. eCollection 2020.
Chinook salmon () declines are widespread and may be attributed, at least in part, to warming river temperatures. Water temperatures in the Yukon River and tributaries often exceed 18°C, a threshold commonly associated with heat stress and elevated mortality in Pacific salmon. Untangling the complex web of direct and indirect physiological effects of heat stress on salmon is difficult in a natural setting with innumerable system challenges but is necessary to increase our understanding of both lethal and sublethal impacts of heat stress on populations. The goal of this study was to characterize the cellular stress response in multiple Chinook salmon tissues after acute elevated temperature challenges. We conducted a controlled 4-hour temperature exposure (control, 18°C and 21°C) experiment on the bank of the Yukon River followed by gene expression (GE) profiling using a 3'-Tag-RNA-Seq protocol. The full transcriptome was analysed for 22 Chinook salmon in muscle, gill and liver tissue. Both the 21°C and 18°C treatments induced greater activity in genes associated with protein folding (e.g. HSP70, HSP90 mRNA) processes in all tissues. Global GE patterns indicate that transcriptomic responses to heat stress were highly tissue-specific, underscoring the importance of analyzing multiple tissues for determination of physiological effect. Primary superclusters (i.e. groupings of loosely related terms) of altered biological processes were identified in each tissue type, including regulation of DNA damage response (gill), regulation by host of viral transcription (liver) and regulation of the force of heart contraction (muscle) in the 21°C treatment. This study provides insight into mechanisms potentially affecting adult Chinook salmon as they encounter warm water during their spawning migration in the Yukon River and suggests that both basic and more specialized cellular functions may be disrupted.
奇努克鲑鱼（）数量的减少十分普遍，这至少部分归因于河流水温升高。育空河及其支流的水温常常超过18°C，这一阈值通常与太平洋鲑鱼的热应激和死亡率升高有关。在一个存在无数系统挑战的自然环境中，厘清热应激对鲑鱼直接和间接生理影响的复杂网络很困难，但对于增进我们对热应激对鲑鱼种群的致死和亚致死影响的理解而言却是必要的。本研究的目的是描述急性高温挑战后多个奇努克鲑鱼组织中的细胞应激反应。我们在育空河岸进行了一项为期4小时的受控温度暴露（对照、18°C和21°C）实验，随后使用3'-标签-RNA-Seq方案进行基因表达（GE）分析。对22条奇努克鲑鱼的肌肉、鳃和肝脏组织的完整转录组进行了分析。21°C和18°C处理均在所有组织中诱导了与蛋白质折叠（如HSP70、HSP90 mRNA）过程相关的基因的更高活性。整体GE模式表明，对热应激的转录组反应具有高度的组织特异性，强调了分析多个组织以确定生理效应的重要性。在每种组织类型中都确定了改变的生物学过程的主要超级聚类（即松散相关术语的分组），包括21°C处理中鳃的DNA损伤反应调节、肝脏的病毒转录宿主调节和肌肉的心脏收缩力调节。本研究深入了解了成年奇努克鲑鱼在育空河产卵洄游期间遇到温水时可能受到影响的机制，并表明基本和更特殊的细胞功能都可能受到干扰。
