RNA-Seq analysis of salinity stress–responsive transcriptome in the liver of spotted sea bass (Lateolabrax maculatus)

Abstract

Salinity is one of the most prominent abiotic factors, which greatly influence reproduction, development, growth, physiological and metabolic activities of fishes. Spotted sea bass (Lateolabrax maculatus), as a euryhaline marine teleost, has extraordinary ability to deal with a wide range of salinity changes. However, this species is devoid of genomic resources, and no study has been conducted at the transcriptomic level to determine genes responsible for salinity regulation, which impedes the understanding of the fundamental mechanism conferring tolerance to salinity fluctuations. Liver, as the major metabolic organ, is the key source supplying energy for iono- and osmoregulation in fish, however, little attention has been paid to its salinity-related functions but which should not be ignored. In this study, we perform RNA-Seq analysis to identify genes involved in salinity adaptation and osmoregulation in liver of spotted sea bass, generating from the fishes exposed to low and high salinity water (5 vs 30ppt). After de novo assembly, annotation and differential gene expression analysis, a total of 455 genes were differentially expressed, including 184 up-regulated and 271 down-regulated transcripts in low salinity-acclimated fish group compared with that in high salinity-acclimated group. A number of genes with a potential role in salinity adaptation for spotted sea bass were classified into five functional categories based on the gene ontology (GO) and enrichment analysis, which include genes involved in metabolites and ion transporters, energy metabolism, signal transduction, immune response and structure reorganization. The candidate genes identified in L. maculates liver provide valuable information to explore new pathways related to fish salinity and osmotic regulation. Besides, the transcriptomic sequencing data supplies significant resources for identification of novel genes and further studying biological questions in spotted sea bass.

Chromosome-level genome assembly of the spotted sea bass, Lateolabrax maculatus

“…Compared with the Japanese sea bass, the spotted sea bass has a broader distribution range that spans from the Bohai Sea to the Indo-China Peninsula [1]. The spotted sea bass is euryhaline, capable of tolerating a wide range of saltwater concentrations; like other euryhaline fishes, it has evolved a unique osmoregulation feature that enables is to adapt to environments with different salinity levels [4]. The spotted sea bass has a delicate flavor and high nutritional content, and is an important commercial fish in China.…”

“…Furthermore, 10,297 SNPs from 219 spotted sea bass individuals belonging to 12 populations along the Chinese coast were used for genetic structure analysis in geographically distant populations [10]. In addition, a comprehensive transcriptome analysis identified sequences of genes involved in salinity adaptation and osmoregulation in the liver of the spotted sea bass, providing insights into the molecular mechanisms behind salinity acclimation in euryhaline teleosts [4]. The profile of differential gene expression in the adult brain and gonads for the spotted sea bass laid the foundation for the understanding of hypothalamus-pituitary-gonad axis gene function and reproduction regulation in teleosts [11].…”

Exposure to salinity stress cause ovarian disruption in a stenohaline freshwater teleost, Heteropneustes fossilis (Bloch, 1794)

“…Fluctuating salinity of aquatic ecosystem is an important abiotic stress that greatly influences reproduction, development, growth and metabolic activities of fish (Yang et al, ; Zhang et al, ). As compared to voluminous studies on the impact of other crucial governing factors such as photoperiod and temperature on reproduction/reproductive system of euryhaline (Lim, Baeck, Kim, & Kim, ; Wuenschel, Werner, & Hoss, ) and stenohaline fish (Acharjee et al, ; Dey, Bhattacharya, & Maitra, ; Renuka & Joshi, ; Sundararaj & Vasal, ), effect of salinity is less explored.…”

“…Fluctuating salinity of aquatic ecosystem is an important abiotic stress that greatly influences reproduction, development, growth and metabolic activities of fish (Yang et al, 2019;Zhang et al, 2017).…”

Time-series transcriptomic analysis of the kelp grouper Epinephelus moara in response to low salinity stress

“…Transcriptomics can be used to investigate the transcriptional regulation of all genes in cells and tissues. The development and application of transcriptomics approaches can not only reveal details of the cellular components, but also help to elucidate the functional genes and components in the genome, which are of great importance for studying the growth and immune responses of organisms (Meng et al 2015 ; Cao et al 2017 ; Zhang et al 2017 ). In recent years, transcriptomics has been applied by aquaculture researchers to study the effects of salinity stress on aquatic animals (Thanh et al 2014 ).…”