Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Biological and Environmental Sciences and Engineering Division, Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Sci Rep. 2021 Sep 13;11(1):18127. doi: 10.1038/s41598-021-97295-3.
The Arabian pupfish, Aphanius dispar, is a euryhaline fish inhabiting both inland nearly-freshwater desert ponds and highly saline Red Sea coastal lagoons of the Arabian Peninsula. Desert ponds and coastal lagoons, located respectively upstream and at the mouths of dry riverbeds ("wadies"), have been found to potentially become connected during periods of intense rainfall, which could allow the fish to migrate between these different habitats. Flash floods would therefore flush Arabian pupfish out to sea, requiring a rapid acclimation to a greater than 40 ppt change in salinity. To investigate the molecular pathways of salinity acclimation during such events, a Red Sea coastal lagoon and a desert pond population were sampled, with the latter exposed to a rapid increase in water salinity. Changes in branchial gene expression were investigated via genome-wide transcriptome measurements over time from 6 h to 21 days. The two natural populations displayed basal differences in genes related to ion transport, osmoregulation and immune system functions. These mechanisms were also differentially regulated in seawater transferred fish, revealing their crucial role in long-term adaptation. Other processes were only transiently activated shortly after the salinity exposure, including cellular stress response mechanisms, such as molecular chaperone synthesis and apoptosis. Tissue remodelling processes were also identified as transient, but took place later in the timeline, suggesting their importance to long-term acclimation as they likely equip the fish with lasting adaptations to their new environment. The alterations in branchial functional pathways displayed by Arabian pupfish in response to salinity increases are diverse. These reveal a large toolkit of molecular processes important for adaptation to hyperosmolarity that allow for successful colonization to a wide variety of different habitats.
阿拉伯叶须鱼（Aphanius dispar）是一种广盐性鱼类，栖息于内陆近淡水沙漠池塘和阿拉伯半岛红海沿海泻湖。沙漠池塘和沿海泻湖分别位于干涸河床（“瓦迪”）的上游和河口，据发现，在强降雨期间它们可能会连接起来，这可以使鱼类在这些不同的栖息地之间迁移。洪水会将阿拉伯叶须鱼冲到海里，这需要它们迅速适应盐度超过 40 ppt 的变化。为了研究这种情况下盐度适应的分子途径，对一个红海沿海泻湖和一个沙漠池塘种群进行了采样，后者暴露于水盐度的快速增加。通过对从 6 小时到 21 天的时间进行全基因组转录组测量，研究了鳃基因表达的变化。这两个自然种群在与离子转运、渗透压调节和免疫系统功能相关的基因上表现出基础差异。这些机制在转移到海水中的鱼类中也被差异调节，揭示了它们在长期适应中的关键作用。其他过程仅在盐度暴露后短暂激活，包括细胞应激反应机制，如分子伴侣合成和细胞凋亡。组织重塑过程也被确定为短暂的，但发生在时间线上较晚，表明它们对长期适应很重要，因为它们可能为鱼类提供适应新环境的持久适应能力。阿拉伯叶须鱼在应对盐度升高时鳃功能途径的改变是多样化的。这些揭示了一套重要的分子过程，这些过程对于适应高渗透压非常重要，使它们能够成功地在各种不同的栖息地中殖民。
