The Transcriptional Profiles Of Multiple Immune-related Genes In Trunk Kidney Of Grass Carp Ctenopharyngodon Idella

Grass carp (Ctenopharyngodon idella) is a vital freshwater aquaculture species in Chinawith the largest production among the “Great Four Cultured Fish”. But the haemorrhagedisease caused by GCRV (grass carp reovirus) results in heavy economic losses every year.GCRV is a member of the Aquareovirus genus of the family Reoviridae, a dsRNA virus.In the present study, trunk kidney of C. idella was used as silica source，we investigatedtranscriptional profiles of twelve representative immune-related genes (TLR (TLR3, TLR7andTLR22); RLR (RIG-I, MDA5and LGP2); NLR (NOD1and NOD2); adaptor molecules(MyD88and IPS-1); Effector molecule type I interferon (IFN-I) and immunoglobulin M (IgM)in trunk kidney tissue of grass carp (Ctenopharyngodon idella)(designated as Ci) injection ofgrass carp reovirus (GCRV) utilizing the real-time fluorescence quantitative PCR (qRT-PCR).The results are as follows:1. The expression of CiTLR3, CiTLR7, CiTLR22, CiMyD88, CiRIG-I, CiMDA5, CiLGP2,CiIPS-1, CiNOD1, CiNOD2and CiIFN-I genes were highy up-regulated compared to thecontrol level at6,12,24,48and72h, which differences were significant (p <0.05), afterGCRV infection (P<0.05) in trunk kidney of C. idalla. The expression of CiIgM mRNAbegan to change dramatically from72h (p <0.05).2. The mRNA expression patterns of these genes (IgM excepted) were examined postGCRV infection, polyinosine-polycytidylic acid (poly(I:C), lipopolysaccharide (LPS) orpeptidoglycan (PGN) stimulation in primary trunk kidney cells of grass carp. The relativevalues of CiTLR3, CiTLR22and CiMyD88were increased post GCRV challenge andviral/bacterial PAMPs stimulation. The mRNA transcriptions of CiTLR7were obviouslyactivated with GCRV challenge. Remarkably, the mRNA expressions of CiRIG-I, CiMDA5,CiLGP2and CiIPS-1were largely up-regulated with GCRV challenge and viral/bacterialPAMPs stimulation. Interestingly, the expression tendencies of CiNOD1and CiNOD2were differential not only in GCRV challenge and poly(I:C) stimulation, but also in LPS and PGNstimulation. It was demonstrated that CiIFN-I induced powerful anti-viral and anti-bacterialeffects in trunk kidney.In summary, these results suggest that trunk kidney of grass carp serves as an importantimmune organ, and plays crucial roles in triggering antiviral and antibacterial immuneresponses both in vivo and in vitro. Although PRRs have been identified, there is still a longway to go to fully clarify the mechanisms of underlying microorganism recognition in teleosts.Further investigation is needed to focus on identifying the accurate signaling pathways ofimmune-related genes, which may contribute to new methods for the prevention of viral andbacterial infections in grass carp culture. And all these foundings will be conducive to providecertain theoretical and practical evidence for the development of effective measures againstviral infection in aquaculture.