Transcriptomic Modulation Reveals the Specific Cellular Response in Chinese Sea Bass (Lateolabrax maculatus) Gills under Salinity Change and Alkalinity Stress

Abstract

Salinity and alkalinity are among the important factors affecting the distribution, survival, growth and physiology of aquatic animals. Chinese sea bass (Lateolabrax maculatus) is an important aquaculture fish species in China that can widely adapt to diverse salinities from freshwater (FW) to seawater (SW) but moderately adapt to highly alkaline water (AW). In this study, juvenile L. maculatus were exposed to salinity change (SW to FW) and alkalinity stress (FW to AW). Coordinated transcriptomic responses in L. maculatus gills were investigated and based on the weighted gene co-expression network analysis (WGCNA), 8 and 11 stress-responsive modules (SRMs) were identified for salinity change and alkalinity stress, respectively, which revealed a cascade of cellular responses to oxidative and osmotic stress in L. maculatus gills. Specifically, four upregulated SRMs were enriched with induced differentially expressed genes (DEGs) for alkalinity stress, mainly corresponding to the functions of “extracellular matrix” and “anatomical structure”, indicating a strong cellular response to alkaline water. Both “antioxidative activity” and “immune response” functions were enriched in the downregulated alkaline SRMs, which comprised inhibited alkaline specific DEGs, revealing the severely disrupted immune and antioxidative functions under alkalinity stress. These alkaline-specific responses were not revealed in the salinity change groups with only moderately inhibited osmoregulation and induced antioxidative response in L. maculatus gills. Therefore, the results revealed the diverse and correlated regulation of the cellular process and stress response in saline-alkaline water, which may have arisen through the functional divergence and adaptive recruitment of the co-expression genes and will provide vital insights for the development of L. maculatus cultivation in alkaline water.

Telomere-to-telomere gapless genome assembly of the Chinese sea bass (Lateolabrax maculatus)

“…The Chinese sea bass shows excellent adaptability to a wide range of temperatures and salinity environments and possesses a delicate taste and high nutritional value 1 , 3 , 4 . Therefore, it has been extensively cultivated in freshwater ponds and seawater net cages in China 5 . In 2021, the yearly production of Chinese sea bass in China reached 199,106 tons, which accounted for 10.79% of the aggregate aquafarming output of marine fish.…”

Transcriptomic Networks Reveal the Tissue-Specific Cold Shock Responses in Japanese Flounder (Paralichthys olivaceus)

“…WGCNA focuses on the modulated regulation of the full-complement gene sets that comprise complex networks, transitioning data analysis from being gene-centric to systematically network-centric [ 18 ]. Therefore, the combination of transcriptome and network analysis will provide insightful implications about the tissue-specific responses of fish to dynamic environmental stresses through the functioning of cellular signaling pathways [ 19 ].…”