Actinobacillus (A.) pleuropneumoniae is one of the most important respiratory pathogens in global pig production. Antimicrobial treatment and vaccination provide only limited protection, but genetic disease resistance is a very promising alternative for sustainable prophylaxis. Previous studies have discovered multiple QTL that may explain up to 30% of phenotypic variance. Based on these findings, the aim of the present study was to use genomic sequencing to identify genetic markers for resistance to pleuropneumonia in a segregating commercial German Landrace line. 163 pigs were infected with A. pleuropneumoniae Serotype 7 through a standardized aerosol infection method. Phenotypes were accurately defined on a clinical, pathological and microbiological basis. The 58 pigs with the most extreme phenotypes were genotyped by sequencing (next-generation sequencing). SNPs were used in a genome-wide association study. The study identified genome-wide associated SNPs on three chromosomes, two of which were chromosomes of QTL which had been mapped in a recent experiment. Each variant explained up to 20% of the total phenotypic variance. Combined, the three variants explained 52.8% of the variance. The SNPs are located in genes involved in the pathomechanism of pleuropneumonia. This study confirms the genetic background for the host's resistance to pleuropneumonia and indicates a potential role of three candidates on SSC2, SSC12 and SSC15. Favorable gene variants are segregating in commercial populations. Further work is needed to verify the results in a controlled study and to identify the functional QTN.

中文翻译：

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抗猪胸膜肺炎的候选基因和基因标记。

胸膜肺炎放线杆菌 (A.) 是全球养猪生产中最重要的呼吸道病原体之一。抗菌治疗和疫苗接种只能提供有限的保护，但遗传病抗性是可持续预防的一种非常有前途的替代方案。先前的研究发现多个 QTL 可以解释高达 30% 的表型变异。基于这些发现，本研究的目的是利用基因组测序来鉴定商业德国长白猪隔离品系中抗胸膜肺炎的遗传标记。通过标准化气溶胶感染方法，163头猪感染了7型胸膜肺炎放线菌。在临床、病理学和微生物学基础上准确定义表型。通过测序（下一代测序）对具有最极端表型的 58 头猪进行了基因分型。SNP 用于全基因组关联研究。该研究在三个染色体上发现了全基因组相关的 SNP，其中两个是 QTL 染色体，已在最近的实验中进行了定位。每个变异解释了总表型变异的 20%。三个变体加起来解释了 52.8% 的方差。SNP 位于涉及胸膜肺炎病理机制的基因中。这项研究证实了宿主对胸膜肺炎的抵抗力的遗传背景，并表明了三种候选物对 SSC2、SSC12 和 SSC15 的潜在作用。有利的基因变异正在商业群体中分离。需要进一步的工作来验证对照研究的结果并确定功能性 QTN。