Effects of high-salinity on the expression of aquaporins and ion transport-related genes in Chinese shrimp (Fenneropenaeus chinensis)

Abstract

Salinity is one of the most common environmental stress factors, which has a substantial influence on the growth, metabolism, and distribution of crustaceans, while transport of ions and water are considered to play important roles in response to salinity stress. The Chinese shrimp (Fenneropenaeus chinensis) is an important shrimp species cultured in northern China and salinity conditions influence its commercial farming significantly. The study aims to elucidate the potential roles of ion-transport related genes Na+/K+-ATPase α subunit (NKAα), cytoplasmic carbonic anhydrase (CAc), and V-type H+-ATPase subunits (VHA-C, VHA-F, and VHA-G), and water channels of aquaporins (AQP3 and AQP4) in F. chinensis under high-salinity stress. The open reading frames (ORFs) of these genes were cloned, validated, and characterized based on blast against the transcriptomic data. Tissue distribution analysis revealed the predominant expression of these genes in the gills. Then, qPCR was used to examine the expression patterns of genes in the post-larvae shrimp and the gills of adult shrimp in response to hyper-osmotic challenges with two salinities (40 and 45). The results showed that the relative expression levels of these genes were all significantly decreased (p < 0.05) in the post-larvae shrimp after 3 h of high-salinity exposure. With continued stress, the expression levels of these genes varied depending on the intensity, exposure time, and treatment conditions of salinity stress. On the other hand, these genes were also significantly down-regulated (p < 0.05) and continuously decreased up to 12 h in the gills of adult shrimp under high-salinity stress. The results indicated the cooperation of these genes to reduce cellular water efflux and ion uptake or excretion in response to high-salinity environments. Our findings provided insights into the regulatory mechanisms employed during the adaption to high-salinity stress of F. chinensis.