Aquaculture Reports (Jul 2021)
Comparative transcriptomic analysis brings new insights into the response to acute temperature acclimation in burbot (Lota lota lota)
Abstract
Temperature is a crucial environmental factor affecting the survival and growth of aquatic organisms. However, the global warming caused by the growth of greenhouse gas emission has severely affected the sustainable development of global nature ecosystem. The change in water temperature has caused a disorder in the aquatic ecosystems. Lota lota lota is a unique member of cold-freshwater codfish; it has an important economic value like its marine relatives. It is also a good model for studying the molecular mechanisms of temperature adaptability of fish. In this study, RNA sequencing based on the Illumina HiSeq™ 2500 platform was used to reveal gene expression at the transcriptome level. Transcriptome profiles were generated from liver and brain samples from fish exposed to (0 °C, 17 °C and 28 °C). A total of 30,958 annotated differentially expressed genes (DEGs) were identified in all comparisons, with more DEGs in high-temperature groups (1668) than in low-temperature groups (1110). GO analysis was divided into three extensive categories and 55 subcategories. A series of candidate genes and pathways associated with temperature responsiveness was detected, mainly including heat-shock protein (HSP) family, fatty acid desaturase (FAD) and antigen processing and presentation. The expression levels of HSP70 were highest amongst those of the HSP family members in the high-temperature groups, implying that HSP70 was an efficient biomarker of high temperature challenge in L. lota lota. An obvious upward trend in the expression of FAD was conducive to regulating fatty acid composition and maintaining membrane fluidity under low-temperature stress. In addition, evidence indicated that elevated temperature had a large influence on immune function and heat stress could upregulate the immune-related pathways in L. lota lota.
