Alternative splicing plays a nonredundant role in greater amberjack (Seriola dumerili) in the adaptation to ambient salinity fluctuations

Alternative splicing (AS) is an important post-transcriptional mechanism for adaptation of fish to environmental stress. Here, we performed a genome-wide investigation to explore the biological importance of AS dynamics in greater amberjack (Seriola dumerili), an economical marine teleost species, in response to hypo- (10 ppt) and hyper-salinity (40 ppt) stresses. The results revealed high level of differential splicing in both gills and kidney upon the exposure to undesired salinity regimes. In gills, genes involved in energy metabolism, stimulus response and epithelial cell differentiation were differentially spliced in response to the deviation of normal water salinity, while sodium ion transport, erythrocyte homeostasis and cellular amide metabolism were enhanced in kidney to combat the adverse impacts of salinity changes. More importantly, the majority of the differentially spliced genes were not differentially expressed, and AS was found to regulate different biological processes from differential gene expression, indicative of the functionally nonredundant role of AS in modulating salinity acclimation in greater amberjack. Together, our study highlights the important contribution of post-transcriptional mechanisms to the adaptation of fish to ambient salinity fluctuations, and provides a theoretical guidance to the conservation of marine fishery resources under the increasingly extreme environmental challenges.