Transcriptome-based analysis of the immune response mechanism of the four-fingered threadfin (Eleutheronema tetradactylum)

Four-fingered threadfin(Eleutheronema tetradactylum), as an ieconomically important agricultural fish species, has been affected by various bacterial diseases in recent years, causing great economic losses in the industry.Vibrio harveyi ,a gram-negative bacterium, caused critically threatened the development of the four-fingered threadfin industry.In this study, we analysed the transcriptome sequencing of the intestine (Cg-IN-VS-Ig-IN) and liver (Cg-LI-VS-Ig-LI) of E.tetradactylum after infection with V.harveyi by using RNA sequencing technology (RNA-seq).Transcriptomic analysis showed that transcription levels of 2783 genes (1831 up-regulated genes and 952 down-regulated) in intestine and 4940 genes (2685 up-regulated and 2255 down-regulated) in liver were altered significantly.Subsequent pathway analysis that the immune pathways significantly enriched in the gut transcriptome were the coagulation and complement cascade response signalling pathway and the IL-17 signalling pathway, respectively. There were six KEGG pathways involved in liver immunity, two of which were identical to the intestinal tissue, namely the coagulation and complement cascade signalling pathway and the IL-17 signalling pathway . In addition, the NOD-like receptor signalling pathway, the Toll and Imd signalling pathway, the RIG-I-like receptor signalling pathway and the Toll-like receptor signalling pathway are specific to liver tissue. The comparative transcriptome analysis study of E.tetradactylum infected with V.harveyi provides some data and theoretical references for the subsequent studies on the immune system and defence mechanism of four-fingered threadfin.