Transcriptome Profiling Of Spleen Provides Insights Into Anti-viral And Anti-bacteria Immunity In Schizothorax Prenati

Schizothorax prenanti(S.prenanti),a famously economical cold-water fish species with high economic value and nutrient value,mainly distribute in southwestern China.With the development of society and economy,the artificial breeding technology of S.prenanti is popularized gradually,and creates tremendous economic value for aquaculture industry.However,the intensive feeding always easily leads to outbreaks various diseases,which causes economic losses of fisherfolk.In order to establish the reasonable measures that can control diseases and reduce the risk of aquaculture,clearly identifying diseases defensing mechanism is extremely required.Therefore,we used Poly(I:C)and LPS to simulate the infection of virus and bacteria respectively,and analyzed the disease defensing mechanism of S.prenanti on gene expression level by RNA-seq.In this study,we used Poly(I:C)and LPS as immunologic stimulant to treat S.prenanti,and successfully established the transcriptome library of spleen.Then,RNA-seq and Trinity sorfware were used to sequencing and do novo assembly respectively,resulting in acquired millions of unigenes of the four libraries.Next,all unigenes were annotated by using seven databases,including NT?NR?GO?COG?KEGG and so on.After the annotation,the unigens of two comparable groups[Poly(I:C)VS PBS and LPS VS PBS]were used to differential expression analysis,the differential expression genes(DEGs)were used to GO and KEGG enrichment analysis and the screening of the immune-related DEGs.On this base,the key genes of anti-viral immunity of Poly(I:C)group were contributed to qPCR validation.Finally,according to RNAseq and qPCR data,we analyzed and deduced the anti-viral and anti-bacteria immune response mechanism of S.prenanti.After sequencing and de novo assembly,163,651 unigenes of the three libraries were acquired,among these unigenes,87.71%unigenes were successful matched in at least one database.In the differential expression analysis,Poly(I:C)group has 313 DEGs containing 268 significantly up-regulated and 45 significantly down-regulated genes,and 47 genes are identified as immune-related DEGs.LPS group has 586 DEGs containing 312 significantly up-regulated and 274 significantly down-regulated genes,and 70 genes are identified as immune-related DEGs.Then,14 anti-viral effectors of Poly(I:C)group were used to qPCR validation.The results showed the qPCR data presented a positive line correlation with RNA-seq data,indicating that the data of RNA-seq are desirable.Finally,we inferred that MDA5-mediated and JAK-mediated signaling pathways may be involved in the anti-viral signaling cascades,which induced type I IFNs and ISGs to block virus invasion,respectively.We inferred that the anti-bacteria response mechanism may start at the recognition of LPS-stimulated signaling by TLR22 and TLR25,following to activate NF-?B by MYD88-or P13K-AKT-mediated signaling pathway,resulting in causes intense inflammatory response to resistance bacterial invasion.In summary,the transcriptome analysis of S.prenanti spleen reveals the mechanism of disease defensing immune response on gene expression level.These results not only provide a desirable sequence information for deep study of S.prenant,but also provide theoretical basis for disease prevention and treatment.