Genome-wide Identification Of Genes Related To The Metabolism Of Glucose-muscle Glycogen-lactic Acid Axis In Chickens

Livestock blood glucose-muscle glycogen-lactic acid metabolism axis affects the body's homeostasis,muscle development and meat quality after slaughter.Blood glucose,muscle glycogen and lactic acid are all typical low heritability quantitative traits.The genetic basis for regulating the metabolism of muscle glycogen and relevant traits has not been systematically revealed.This study combined the use of genome-wide association study(GWAS)and transcriptome expression profiling to identify candidate functional genes that regulate the glucose-muscle glycogen-lactic acid metabolism axis,revealing the genome-wide genetic molecules of the blood glucose-muscle glycogen-lactic acid metabolism axis of chickens,providing a theoretical basis for the genetic improvement of the muscle metabolism traits of chicken muscle tissue and the comprehensive nutritional control strategy in the future.The study mainly includes the following two trials:474 98-day-old Jingxing yellow female chickens were used to determine the blood glucose,muscle glycogen and lactic acid contents in the breast muscle tissue;The whole genome resequencing technology was used to screen the genome SNP and INDEL,and Linkage disequilibrium modified Bonferroni was used to correct the P-value and to calculate the potential correlation P thresholds of SNP(1.43E-6,1/699341)and INDEL(1.32E-6,1/755733).GWAS of blood glucose,muscle glycogen and lactic acid traits showed that 6 SNPs were related to blood glucose,UBE3 D and ACAD9 were located near the genes through gene annotations.while 9 SNPs and 3 INDELs were potentially related to muscle glycogen,CPNE4,FOSL2 and NKD1 were located near the loci through gene annotations.The phenotypes of SNP(chr3: 78300536)and SNP(chr12: 5130488),which are potentially associated with blood glucose traits,reached significant levels in wild-type and mutant individuals,and there were significant additive effects.It was found that phenotypes of all SNPs or INDELs reached significant differences between wild type and mutant individuals related to muscle glycogen,and a significant additive effect existed.Fluorescence quantitative analysis showed that the expression of the FOSL2 gene in breast muscle tissue of mutant individuals carrying INDEL(chr3: 27425548)was significantly lower than that of wild type(P<0.01),while GRIA3 in breast muscle tissue of mutant individuals carrying SNP(chr4: 15746019)the gene expression level was significantly higher than that of wild type(P<0.01),and the expression levels of other candidate genes were not different between mutant and wild type individuals.Based on the results of Trial 1,Differentially expressed genes(DEGs)and Weighted Gene Co-Expression Network Analysis(WGCNA)were performed on breast muscle tissues of individuals with high and low muscle glycogen.DEGs results showed that a total of 1171 significantly differentially expressed genes were fund,including PRKAG,CEBPB,FOSL2,FOX1,AMPK,and PIK3 C,which represent muscle glycogen-related functional genes;for GWASassociated muscle glycogen of the original candidate functional genes,only FOSL2 was in the high muscle glycogen group was significantly lower than that in the low muscle glycogen group,and the expression level of the candidate gene FOSL2 was extremely significantly negatively correlated with muscle glycogen content;in addition,the expression changes of FOSL2 activated muscle glycogen metabolism-related genes CEBPB and FOSL2 consistently,the breast muscle tissue in the high-muscle glycogen group was significantly lower than that in the low-muscle glycogen group.WGCNA analysis results show that FOSL2 is negatively correlated with muscle glycogen content,CEBPB,MAP3K14,SLC2A14,PPP2 CA,SLC38A2,and PPP2R5 E and other classic glycometabolism related genes are also related to muscle glycogen content and co-expressed with FOSL2;Genes with P <0.05 in the midnightblue module are enriched in the pathway,enriched in the mTOR signaling pathway,FOXO signaling pathway and insulin signaling pathway.The above results suggest that FOSL2 may reduce muscle glycogen content by activating CEBPB gene expression.This study analyzes the genome-wide molecular basis of the regulation of chicken blood glucose-muscle glycogen-lactic acid axis.Through whole-genome association study and functional analysis,effective muscle glycogen INDEL(chr3:27425548)was identified,which can reduce muscle glycogen content after mutation.DEGs and WGCNA analysis also revealed that FOSL2 is negatively correlated with muscle glycogen content and co-expressed with multiple classic genes related to glucose metabolism.FOSL2 is an important candidate gene affecting muscle glycogen content.