Liver transcriptome changes in pearl gentian grouper in response to acute high-temperature stress

Abstract

Pearl gentian grouper is the main cultivated grouper variety along the southeast coast of China. However, the coastal waters often experience prolonged of high temperatures during summer due to global climate warming and frequent extreme high-temperature events near the coast. As a result, the high-temperature stress seriously hinders the development and growth of grouper aquaculture. In this study, SMRT-Seq and RNA-Seq sequencing techniques were used to analyze the gene expression changes in the pearl gentian grouper liver under room temperature (25 °C) and acute high temperatures (30, 34, 38, and 38 °C for 6 h). Based on the differential expression analysis, Short Time-series Expression Miner (STEM), and Weighted Gene Co-expression Network Analysis (WGCNA), 4144 differentially expressed genes (DEGs), two significantly expressed gene profiles (Profile0 and Profile19), and two high-temperature specific modules (Blue and Turquoise) were identified. The results revealed that the grouper responded to acute high-temperature stress by regulating genes enriched in biological processes, such as protein homeostasis, oxidative defense, apoptosis, and glucose and lipid metabolisms. Furthermore, 34 °C and 38 °C were confirmed as the key temperature points for the significant alterations in the physiological and metabolic processes of pearl gentian grouper under high-temperature stress, corresponding to the critical suitable growth temperature and high-temperature tolerance, respectively. The findings in this study provide a solid theoretical basis for understanding the high-temperature adaptation mechanism of pearl gentian grouper. They also provide important guidelines for promoting the development of the grouper aquaculture industry and molecular breeding high-temperature resistant grouper varieties.