Comparative Transcriptomics-based Analysis of Common Carp (Cyprinus carpio) Kidney Tissues Reveals Differential Immune Responses at Two Temperatures

Background: Common carp is the third most widely farmed fish, globally. It is tolerant to cold stress and resistant to EUS pathogenic infections, when it faces lower temperatures. In the present study, common carp was used as the research model to examine the interplay of temperature and immunity. Methods: High-throughput transcriptome sequencing was used to study the differential gene expression profiles of kidney tissues, reared at two different temperatures; 30oC (control) and 20oC (experimental). Result: Out of 588 differential expressed genes (DEGs), genes under GO terms for abiotic stress were categorised under oxidative stress, response to heat, mechanical stimulus and cold. Fifteen DEGs were found under the immune category, which out of which twelve were under the innate immune category, included 5 lectin family members and 1 tumor necrosis factor. The information generated in common carp would form a transcriptome resource for tolerance to abiotic stress. At the lower temperature studied, modulatory immune response, through the cytokine-cytokine interaction pathway, seems to be a major player, besides higher energy production, up-regulated stress responses, cell growth and survival. These results have the potential to be developed into bio-markers for temperature stress tolerance and modulatory immune responses in aquaculture pond production during the lower temperature conditions.