Genome−wide expression profile analysis of the NHE and NKA gene family in Rachycentron canadum (Linnaeus, 1766) and its response to salinity adaptation

NHE and NKA are important regulators of ion transport in fish play a pivotal role maintaining osmotic balance adapting to salinity changes. However, no systematic identification functional analysis has been conducted for NHEs NKAs the cobia ( Rachycentron canadum ), commercially worldwide flatfish. Herein,12 genes were found be distributed on 10 chromosomes 12 9 identified R. at genome-wide level. Histopathological examination gills demonstrated response gill lamellae chloride cells salinity, while microstructure intestine kidney exhibited changes associated with salinity. The findings show that members gene families widely gill, brain, heart tissues. Specifically, high expression levels somatic kidney, whereas displayed prominent heart. Moreover, adaptation experiments examine genes. In intestine, NHE1 was significantly upregulated following both low salt stimulation, proportional Notably, significant downward trend NHE2c observed increasing Following low-salt acclimation, NKAα1b NKAβ3a down-regulated NKAα3a up-regulation down-regulation respectively. , up-regulated. During high-salt patterns consistent those during NKAβ1b upregulation. Our underscore conservation family highlight tissue-specific their responses These results provide valuable insights into molecular mechanisms governing osmoregulation contributing development novel strategies enhancing aquaculture practices this species.