Analysis of differentially expressed genes in the sea cucumber Apostichopus japonicus under heat stress

The high-throughput RNA-seq was applied under both 26°C and 30°C heat stress in Apostichopus japonicus, which revealed characterization of gene expression at sub-lethal and lethal limit temperature. The results will help to better understand the characteristics of heat shock response in A. japonicus. Overall design: The sea cucumbers in control group were still kept at 18°C without any change, and the intestine tissue was sampled from the control group. For the heat stress experiment, sea cucumbers went through a temperature-rise process from 18°C to 26°C or to 30°C respectively, with a rate of 2°C per hour by using a heating rod. Then the water maintained at the treatment temperature, and the initial time was set with the moment when the temperature reached 26°C or 30°C. After 6 h and 48 h from initial time, the sea cucumbers 26°C treatment were sampled with intestine tissue, which was regarded as the group 26°C_6h and 26°C_48h respectively. After 6 h from initial time, the sea cucumbers 30°C treatment were sampled with intestine tissue, which was regarded as the group 30°C_6h. All the samples were quickly frozen in liquid nitrogen, and then stored at -80°C for further usage.