Comparative transcriptional profiling analysis of the effect of heat waves during embryo incubation on the hatchlings of the Chinese soft-shelled turtle ( Pelodiscus sinensis ).

Temperature is one of most the important environmental factors that affect the ontogenesis of organisms. In this study, we incubated Chinese soft-shelled turtle eggs at 28°C (control temperature, C treatment), a temperature with a 16°C cold shock and a 36°C heat shock twice per week (S treatment) or a ramp-programmed temperature of 29 ± 9°C (with 12 hr (+) and 12 hr (-) every day) (F treatment). The incubation period, hatching success, hatchling weight, and locomotor performance were significantly different between the controls and the different heat treatment groups. The pathogen challenge results illustrated that hatchlings from the S treatment group were more resistant to bacterial infection, whereas hatchlings from the F treatment group were more vulnerable. We used RNA-seq quantification analysis to identify differentially expressed genes (DEGs) of hatchlings in the S treatment group. Based on the functional annotation results for the DEGs, 9 genes were chosen to verify the RNA-seq results. The background expression of DEGs was also analyzed for the three treatments, as was the regulation of the pathogen challenge. The results showed that 8 DEGs were related to the immune response after pathogen challenge and that temperature was an important factor in differential regulation of the immunity pathways.