烟草青枯病抗性的全基因组关联分析

为发掘并定位烟草青枯病抗性遗传位点，利用RAD简化基因组重测序技术（RAD-seq），以219份遗传多样性较高的国内外烟草品种作为供试自然群体，利用田间病圃鉴定供试材料的青枯病抗性，通过全基因组关联分析（GWAS），发掘抗病基因组区段，并进行抗病候选基因预测。结果表明，筛选鉴定到8个高抗青枯病的烟草品种，获得了384 904个高质量的SNP位点，对烤烟群体的基因组连锁不平衡衰减（LD）距离进行了估算，平均为256 kb。在烟草基因组内发掘到1个与烟草青枯病抗性变异显著关联的区段，峰值SNP在17号染色体的23 977 382 bp处，p=6.196×10^-7，能解释14.29%的表型变异，在该区段内预测到4个抗病候选基因。本研究为烟草青枯病抗病基因克隆及分子育种提供了较为明确的基因组定位信息。

Genome-wide Association Study of Resistance to Tobacco Bacterial Wilt

In order to discover and locate the genetic locus of resistance to tobacco bacterial wilt, using restriction site-associated DNA sequencing (RAD-seq) technology, and 219 domestic and foreign tobacco varieties with high genetic diversity as the natural population, the resistance to bacterial wilt of the tested materials was identified by field disease nursery, through genome-wide association study (GWAS) to discover disease-resistant genome segments and predict candidate genes for disease resistance. The results showed that 8 tobacco varieties with high resistance to bacterial wilt were identified, and 384 904 high-quality SNP loci were obtained. The distance of genome linkage disequilibrium (LD) attenuation of flue-cured tobacco population was estimated to be 256 kb in average. A segment significantly associated with tobacco bacterial wilt resistance variation was discovered in the tobacco genome, with the peak SNP at 23 977 382 bp on chromosome 17, and the p=6.196×10^-7, which can explain 14.29% of the phenotype variation. Four disease resistance candidate genes were predicted in this segment. This study provides genomic location information for the next step of tobacco bacterial wilt resistance gene cloning and molecular breeding.