The characteristics of aminotransferases gene family in Ruditapes philippinarum and its response to salinity stresses

Aminotransferase is involved in the regulation of amino acid metabolism, which can affect the balance and distribution of amino acids in the organism, help maintain the homeostasis of amino acids in the organism, and play an important role in the environmental adaptation of aquatic animals. In this study, a total of 28 aminotransferase genes were identified in the genome of R. philippinarum. The gene structure, protein structure, chromosome localization, and phylogenetic analysis of aminotransferase were conducted using bioinformatics. According to the gene structure and phylogenetic analysis of aminotransferase proteins, aminotransferase proteins can be categorized into class I and II, class III, and class V. RNA-seq data analysis showed that aminotransferase genes were differentially expressed at different developmental stages, tissues, and salinity stress. In addition, qPCR demonstrated that the expression levels of most aminotransferase genes increased significantly during salinity changes. We also measured the free amino acids content in the gills of R. philippinarum after 48 h of low and high salinity stress. The results indicated that the total free amino acids under low salinity stress (75.89 ± 3.31 mg/g) and high salinity stress (91.01 ± 3.31 mg/g) at 48 h were significantly decreased and increased compared with the control group (83.01 ± 3.12 mg/g), respectively. The results of this study provide a valuable reference for further research on the salinity adaptation of the aminotransferase gene in R. philippinarum.