Interaction Analysis Between CircRNA/lncRNA,Microbiota And Metabolites In Rumen Epithelium Of Tibetan Sheep In Warm And Cold Seasons

Tibetan sheep is the dominant breed in the Tibetan Plateau,and its grazing behavior and production performance are widely affected by the plateau environment.For example,during the long cold season,the forage yield and nutrients are far lower than the demand,which causes nutrient stress to Tibetan sheep and other domestic animals in the cold season,and seriously limits its industrial development and innovative utilization of germplasm resources.Previous studies on the genetic mechanism of plateau adaptation have mostly focused on the variation of the animal’s own genetic material,and little attention has been paid to the important contribution of the "second genomes" of gut microorganisms and their metabolites that co-evolve with the host.Therefore,in this study,16 S r RNA,transcriptome,metabolome and real-time fluorescence quantitative PCR(RT-q PCR)is used to explore the effects of co-evolution of host genome(the first genome)and gut microorganisms(the second genome)on nutritional stress in Tibetan sheep during cold season,so as to provide a basis for elucidating the plateau adaptation mechanism of Tibetan sheep.The main results are as follows:1.Identification and functional analysis of differential expression(DE)circRNAs and lncRNAs in rumen epithelium of Tibetan sheep in warm and cold seasons(1)A total of 56 DE circRNAs were identified in the rumen epithelium of Tibetan sheep in warm and cold seasons by RNA-seq technology,and 29 of them were significantly up-regulated in cold season.KEGG enrichment analysis showed that circRNAs source genes were significantly enriched in lysine degradation,amino acid synthesis and protein processing in endoplasmic reticulum.circRNA-mi RNA regulatory network showed that circRNAs promoted the adaptation of Tibetan sheep in cold season by combining targeted mi R-150 and oar-mi R-370-3p.(2)A total of 172 DE lncRNAs were identified in the rumen epithelium of Tibetan sheep in warm and cold seasons by RNA-seq technology,and 87 of them were significantly up-regulated in cold season.KEGG enrichment analysis showed that the target genes of lncRNAs were significantly enriched in MAPK signaling pathway and insulin signaling pathway,and the target genes of up-regulated lncRNAs in cold season were significantly enriched in TNF signaling pathway and oxidative phosphorylation pathway.LncRNA-mi RNA regulatory network showed that lncRNAs were involved in the regulation of nutritional stress in Tibetan sheep during cold season by combining and targeting ATP1B2,CADPS,TLR5 and UGT1A6.2.Interactions analysis of rumen epithelial circRNAs/lncRNAs-microbiota and their metabolites(1)Tibetan sheep rumen epithelial circRNAs and microbiota and its metabolites correlation analysis results show that circRNA NC＿040275.1:28680890|28683112were significant positive correlation with acetic acid,propionic acid,butyric acid and total VFA(P<0.01),and positive correlation with the Ruminococcus-1(P<0.05).In addition,circRNA NC＿040256.1:78451819|78454934 and serine and proline accumulation in the same KEGG pathways of amino acid biosynthesis pathways.(2)Correlation analysis between rumen epithelial lncRNAs and microbiota and their metabolites showed that some DE lncRNAs were significantly correlated with acetic acid,propionate,butyrate,total VFAs and ruminal epithelial morphology(P<0.05).And there was a significant negative correlation with the microbiota Butyrivibrio-2 and Succiniclasticum(P<0.05).In addition,lncRNAs and bilirubin and other metabolites were enriched in the same KEGG pathway bile secretion.In conclusion,circRNAs and lncRNAs of rumen epithelium played an important role in nutrient stress adaptation of Tibetan sheep in cold season,and circRNAs mediated host to participate in efficient VFA transport and amino acid anabolic function in cold season.LncRNAs mediate the host to participate in the regulation of nutrient absorption,energy utilization and immune response in cold season,suggesting that the host genome and microorganisms genome promoted Tibetan sheep to cope with nutrient stress in cold season through co-evolution.