基于PRRSV人工感染资源群体解析猪蓝耳病抗病性状的遗传基础

猪繁殖与呼吸综合征（PRRS）给养猪业造成巨大经济损失，抗病育种成为解决该病防控的希望。申请者前期发现通城猪和大白猪存在PRRS抗病性差异，并以抗病通城猪和易感大白猪为亲本进行杂交，通过多代横交构建资源群体。本研究选择400头个体进行PRRSV人工感染试验，测定免疫应答性状和肠道菌群结构获得表型信息，利用SNP芯片进行全基因组扫描获得基因型信息并进行QTL 定位；对筛选出的抗病和易感个体进行转录组、代谢组和肠道菌群宏基因组测序，通过多组学整合分析鉴定影响免疫应答的候选基因和肠道菌群；分别通过基因敲除、超表达、信号通路等研究鉴定抗病候选基因功能及其机制，鉴定变异位点和分子标记；通过菌群和菌株的敲除和敲入研究肠道菌对宿主抗病的作用及机制。研究结果为抗病遗传机制解析提供依据，鉴定的抗病候选基因及其分子标记具有重要的育种应用价值。立项研究对猪蓝耳病的抗病遗传育种具有重要的理论意和应用前景。

Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), is one of the most important infectious diseases in pig industry. Disease-resistance breeding has become an effective approach to prevent and control PRRS epidemic. Our previous studies have indicated that Tongcheng (TC) pigs, a Chinese local breed, have stronger resistance or tolerance to PRRSV infection than Large White (LW) pigs. In order to explore genetic resistance to PRRSV, we construct segregation population by crossing PRRSV-resistant TC pigs and PRRSV-susceptible LW pigs. Furthermore, this segregation population will be artificial infected with PRRSV. Then, we will carry out the following researches with this PRRSV infection resource population: (1)The clinical symptoms, blood routine, cytokines, viral load, body weight and individual viability will be measured after artificial PRRSV infection in vivo. (2) Individual genotype information will be obtained with high-density SNP chips, and QTL mapping will be performed on different traits and the microbial community structure in the gut using the mixed linear model, FarmCPU and other statistical methods. (3) the transcriptome, metabolome and fecal metagenomics will be conducted in the selected disease-resistant and disease-susceptible individuals, and multi-omics integrated analysis will be used to identify disease-resistant genes, markers, intestinal bacteria and pathways affecting immune response to PRRSV infection. (4) the mechanism of gut microbes influenced on host disease resistance will be deeply explored through the knock-in flora PRRS-susceptible pigs and gut microbe in germ-free mice. (5) The functions of disease-resistant genes will be studied by gene knockout, overexpression, signaling pathway analysis in different cell lines. The regulatory mechanism also will be investigated. In conclusion, the results obtained from this study will provide genetic basis for PRRS-resistance breeding. Besides, the surviving individuals, identified disease-resistant genes, markers and the will be valuable materials for future PRRS-resistance breeding.