| Salmonella Pullorum is one of the most prevalent bacterial disease that restricts the development of poultry industry. Vaccination, purification, antibiotics and other drugs are the mainly preventive measures to control Salmonella Pullorum infection, but all of these have shortcomings. Following the development of disease-resistance breeding, selecting the groups with strong resistance to disease by molecular markers joint breeding is one of the most effective methods. During infection, the host inflammatory reaction is initiated by innate immunity. As a key protein in TLRs signaling pathway, MyD88 functioning against bacteria infection is largely known. In the past years, up-regulation of MyD88 gene in Salmonella Pullorum and regulating in transcription and translation of 3’-UTR were frequently reported, while the mechanisms of post-transcriptional control has not been reported yet. The AREs is functional component in 3’-UTR. Accumulating evidence implies that AREs regulating the biological activities of proteins is related to the mRNA stability and translation efficiency. But the relationship between 3’-UTR of MyD88 gene and the susceptibility to Salmonella Pullorum keeps unknown in chicken.To detect whether 3’-UTR of MyD88 gene is associated with resistance to Salmonella Pullorum, we performed a genetic association study between Generation 04 and Generation 05 in SD quality chicken population.4,400 Er-lang mountainous hens have been tested at the time of 300 days of age by whole blood glass plate agglutination. Gathering infected subjects into 2 case-groups, containing 81 cases of Generation 04 and 61 cases of Generation 05, while 2 control-groups containing 90 controls of Generation 04 and 66 controls of Generation 05. All the samples collect by the vein under wings of chicken. The genomic DNA was extracted by using the standard phenol/chloroform method. Amplified 3’-UTR in MyD88 gene of all samples, the products were directly sequenced and screened SNPs out. Contrasted difference of allele frequency and genotype frequency distribution in case-control groups between the two generations by R software. Then, Hardy-Weinberg equilibrium and association analysis were conducted by Haploview software.The results show that:1.13 SNPs were found in the two generation, among which 10 SNPs in line with the Hardy-Weinberg equilibrium.The allele frequency and genotype frequencies of SNP4 (g.4810293 C>A) was of significant difference (P<0.05) in Generation 04. The OR and 95%CI value of SNP4 were 0.6088 and 0.531-0.9759, showed that the loci was resistance to Salmonella Pullorum. Only the allele frequency of SNP13 was of significant difference (P< 0.05) in Generation 05. The OR and 95%CI value of SNP13 were 1.8012 and 1.0247-1.4827, declared that SNP13 was susceptibility to Salmonella Pullorum.2. The haploid types GG, AA that composed by SNP1, SNP2 (g.4810266 A>G, g.4810372 C<T) in Generation 04 and haploid types GTG, ACA, GCG, ACG, GCA that composed by SNP1,SNP2 and SNP11 in Generation 05 showed no significant difference between case and control groups (P>0.05). But SNP1 and SNP2 were strong linkage disequilibrium with SNP6, SNP7 and SNP8, which was different with the situation in Generation 05. The data declared that the selection of Generation 04 resulted in the resistance/susceptibility of mutations sites in Generation 05.Collectively, SNPs shows resistance or susceptibility to Salmonella Pullorum in different generation. Single nucleotide polymorphisms of 3’-UTR in MyD88 gene has an certain association with Salmonella pullorum infection, the data in the study can be used for molecular markers-assisted selection in future studies. |
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