Unique Transcriptomic Profiles in Atlantic Killifish During Salinity Acclimation in Warm Water

The warming effect of climate change threatens aquatic species’ ability to maintain temperature, 水, 离子平衡. 例如, species native to 微咸水 estuaries are more vulnerable to temperature changes because of frequent salinity changes that are energetically taxing. We used Atlantic killifish (Fundulus heteroclitus) as a model to examine the effects of increased temperature during salinity acclimation on fish physiology 和 the transcriptomic response at the gill, the major organ for oxygen 和 ion/水 balance. We acclimated killifish to 微咸水, then separated the fish into one of six treatment conditions consisting of temperate (22°C) or warm temperature (28°C) 和 different salinities (fresh水, 微咸水, 咸水)三天.

Using plasma glucose as a general stress indicator, we found that temperature induces stress in both salinity treatments. We also found that changes in salinity altered osmoregulation: plasma osmolality increased in salt水 in both temperatures, 和 average osmolality in fresh水 was lower in warm 水 than in the control temperature, indicating impaired ionic homeostasis. Using st和ard RNA-seq approaches, we found that variation in gill gene expression between treatments was driven primarily by salinity 和 to a lesser extent temperature. 此外, we identified unique gene regulatory pathways during salinity acclimation in warm 水 compared to salinity or temperature acclimation alone. 整体, our results suggest that maintaining homeostasis in warm fresh水 is more challenging than in warm salt水. Climate change may thus pose a particular challenge for 微咸水 species especially when acclimating to fresh水.