Study On Genetic Variants In PGAM2 Promotor Region And Its Association With Water Holding Capacity In Pigs

Water holding capacity(WHC)is the capacity of meat to maintain its water during application of external forces.WHC directly affects economic benefits,because loss of tissue fluid is associated with pork weight loss.It also affects nutritional value,sensorial and technological properties of porcine meat.Thus,WHC is of great importance for the pork industries and the consumers.One of the mostly studied pathways that affect WHC is glycolytic process,and PGAM2?PHKG1?LDHA gene code the important enzyme in glycolytic process,several studies have demonstrated that these genes are associated with meat qualities,they may affect WHC through glycolytic process.In this study,we chose these three genes as our candidate genes,and one SNP found in PGAM2 promotor region can affect PGAM2 expression and WHC.Firstly,we found PGAM2 and PHKG1 gene expression level were negatively correlated with WHC(p<0.05).We sequenced the promoter region of two genes using DNA pool of high and low WHC groups(n = 14 for each group)and identified one polymorphism c.-360T>C that had opposite allele distribution in two pools in PGAM2.Next,the polymorphism was genotyped in Duroc x Large White x Yorkshire(D×L×Y)crossbred pigs(n = 170)by allele-specific PCR(AS-PCR).We found that the CC genotype was associated with lower WHC and higher PGAM2 mRNA,and the TT genotype corresponded to higher WHC and lower PGAM2 mRNA level(p<0.05).Luciferase activity assay also showed that CC genotype promoter had higher activity than TT genotype(p<0.05).Using Transcription factor prediction online tool,we found out that the c.-360T produces a binding site for transcriptional factors LTSM;while the site of c.-360C can be bound by factors CREB,TaxCREB,and v-MAF.Moreover,CC genotype had higher lactate level and lower pH2 than TT genotype(p<0.1).In summary,we identified one SNP in porcine PGAM2 promoter which was associated with WHC and PGAM2 gene transcriptional activity,and investigated the mechanisms in glycolytic process underlying WHC through genetic approach,therefore provided meat quality associated maker for pigs selection and breeding.