Comprehensive Analysis of Whole-Transcriptome Profiles in Response to Acute Hypersaline Challenge in Chinese Razor Clam Sinonovacula constricta

Abstract

The Chinese razor clam (Sinonovacula constricta) is an important for Chinese aquaculture marine bivalve that naturally occurs across intertidal and estuarine areas subjected to significant changes in salinity level. However, the information on the molecular mechanisms related to high salinity stress in the species remain limited. In this study, nine gill samples of S. constricta treated with 20, 30, and 40 ppt salinity for 24 h were used for whole-transcriptome RNA sequencing, and a regulatory network of competing endogenous RNAs (ceRNAs) was constructed to better understand the mechanisms responsible for adaptation of the species to high salinity. A total of 83,262 lncRNAs, 52,422 mRNAs, 2890 circRNAs, and 498 miRNAs were identified, and 4175 of them displayed differential expression pattern among the three groups examined. The KEGG analyses of differentially expressed RNAs evidenced that amino acid synthesis and membrane transport were the dominant factors involved in the adaptation of the Chinese razor clam to acute salinity increase, while lipid metabolism and signaling played only a supporting role. In addition, lncRNA/circRNA-miRNA-mRNA regulatory networks (ceRNA network) showed clearly regulatory relationships among different RNAs. Moreover, the expression of four candidate genes, including tyrosine aminotransferase (TAT), hyaluronidase 4 (HYAL4), cysteine sulfinic acid decarboxylase (CSAD), and ∆1-pyrroline-5-carboxylate synthase (P5CS) at different challenge time were detected by qRT-PCR. The expression trend of TAT and HYAL4 was consistent with that of the ceRNA network, supporting the reliability of established network. The expression of TAT, CSAD, and P5CS were upregulated in response to increased salinity. This might be associated with increased amino acid synthesis rate, which seems to play an essential role in adaptation of the species to high salinity stress. In contrast, the expression level of HYAL4 gene decreased in response to elevated salinity level, which is associated with reduction Hyaluronan hydrolysis to help maintain water in the cell. Our findings provide a very rich reference for understanding the important role of ncRNAs in the salinity adaptation of shellfish. Moreover, the acquired information may be useful for optimization of the artificial breeding of the Chinese razor clam under aquaculture conditions.

Effects of medium- and long-term high-salinity environments on free amino acid content and related genes of Sinonovacula constricta

“…Previous studies have reported that salinity stress activated the expression of genes related to amino acid metabolic pathways, such as ATPGD, CSAD, and P5CS, in response to changes in osmotic status and adaption to osmotic stress conditions in the Manila clam Ruditapes philippinarum (Nie et al, 2017). Similarly, in S. constricta, the changes in the expression of these genes at high salinity occur because free amino acids play important roles in regulating osmotic pressure in razor clams (Cao et al, 2023). ACOX1 is an important gene in the development and nutritional regulation of aquatic animals (Morais et al, 2007), which regulates the conversion process between propionyl-COA and acrylyl-COA, thereby affecting the synthesis of Ala (Oaxaca-Castillo et al, 2007).…”

Epigenetic modification: A novel insight into diabetic wound healing

“…ncRNAs can be classified as small nuclear RNAs (snRNAs) or long noncoding RNAs (lncRNAs) based on the quantity of nucleotides they contain. snRNAs can be separated into circular RNAs (circRNAs) and microRNAs (miRNAs) based on distinct production pathways [ 127 ]. Since the discovery of the RNA interference process, researchers have paid increasing attention to the processes of non-coding RNA (ncRNA) regulation [ 128 ].…”