Integrated analysis of transcriptome and metabolome reveals chronic low salinity stress responses in the muscle of Exopalaemon carinicauda

Low salinity environment is one of the key factors threatening the survival of aquatic organisms. Due to the strong adaptability of low salinity, Exopalaemon carinicauda is an ideal model to study the low salinity adaptation mechanism of crustaceans. In this study, E. carinicauda from the same family were divided into two groups, which were reared at salinity of 4 ‰ and 30 ‰, respectively. Integrated analysis of transcriptome and metabolome was used to uncover the mechanisms of E. carinicauda adaptation to chronic low salinity environment. Under the chronic low salinity stress, a total of 651 differentially expressed genes (DEGs) and 386 differential metabolites (DMs) were obtained, with the majority showing downregulation. These DEGs mainly involved MAPK signal transduction pathway and structural constituent of cuticle. Besides, chitin binding and chitin metabolism process were inhibited significantly. Among the DMs, lipids and lipid-like molecules, flavor amino acids and nucleotides were detected, which may be related to the adjustment of energy metabolism and flavor of muscle. In addition, ubiquinone and other terpenoid-quinone biosynthesis pathway and alanine, aspartate, and glutamate metabolic pathway were induced. These results will enrich our understanding of the molecular mechanism underlying the chronic low salinity tolerance in E. carinicauda, providing an important theoretical basis and practical guidance for the research and breeding, thereby promoting the sustainable development of aquaculture.