| Marek's disease(MD)is a lymphoproliferative tumor disease which caused by Marek's disease virus(MDV).It is prevalent in poultry industry all over the world,which causes huge economic losses to poultry industry every year.The resistance mechanism of chicken to MD is very complex,which is usually achieved by the joint action of multiple genes.Single nucleotide polymorphism(SNP)is the most common type of genetic variation in human and animal genomes,which can reflect the difference of individual genetic resistance.At present,a large number of SNPs related to the disease resistance and susceptibility of chicken have been identified.It was found that there are two SNPs related to Marek's disease resistance in White Lehorn chicken genome,which are rs14527240 in intron 7 of SMOC1 and GGaluga156129(No.rs312873078)in intron 22 of PTPN3.There is significant correlation between gene expression of SMOC1 and PTPN3 and tumor formation.In this study,genomic DNA was extracted from 6500 Partridge Shank chicken,and then the genotypes of SMOC1 and PTPN3 were measured by PCR-RFLP method.It was found that there were different genotypes in Partridge Shank chicken.The homozygous mutation of SMOC1 was1.93%,and that of PTPN3 was 28.03%,and both of these two loucis homozygous mutation was0.246%.In order to further explore the correlation between two SNPs and the resistance to Marek's disease in Partridge Shank chicken.A total of 87 chickens with homozygous mutation and non homozygous mutation were selected to challenge Md5 strain of Marek's disease.Md5 was inoculated intraperitoneally to 1-day-old chickens(2000PFU)with different genotypes.The experiment lasted for 97 days.The chickens were slaughtered and samples were collected on the46 th and 97 th days of the experiment,respectively.The specific bands of meq(MDV oncogenic gene)could be amplified from the genomic DNA of spleen tissues of infected chickens.The result indicated that the infection rate of MDV was 100%.In the first batch,12 chickens were randomly selected and slaughtered,and no typical tumor lesions were found.Due to the influence of COVID-19,only 8 chickens were randomly selected in the second batch three chickens(containing both GG genotype of SMOC1 and GA genotype of PTPN3)showed typical symptoms of Marek's disease.The anatomical observation of the other five chickens(GA/AA genotype of SMOC1,GG genotype of PTPN3)showed healthy.No death cases had occurred until the end of the experiment.The tissues of liver and heart in Disease Group and Health Group were observed by histological section.Combined with the statistics result of genotype and disease incidence,we concluded that GA/AA genotype of SMOC1 was associated with the resistance to Marek's disease(P < 0.05),and the GG type of PTPN3 was associated with the resistance to Marek'sdisease(P < 0.05),After correlation analysis.The relative gene expressions of SMOC1,PTPN3,IFN-?,IL-1 ?,IL-6,IL-8 and IL-18 were detected by QPCR.The results showed that SMOC1 expression in spleen tissue of Disease Group was significantly higher than that of Health Group(P < 0.05),but the expression of PTPN3 had no significant difference.Compared with Health Group,the expression of IFN-?,IL-1 ?,IL-6,IL-8and IL-18 was significantly increased in Disease Group.However,the expression level was not significant(P > 0.05)in statistic analysis.According to the analysis results,it could be concluded that the expression of SMOC1 was related to tumorigenesis;that the expression of cytokines such as IFN-?,IL-1 ?,IL-8 and IL-18 had no significant difference among different genotypes. |
PDF Full Text Request