摘　要：含抗性基因的水稻品种易被病原菌克服，因此为进一步发掘新的稻瘟病抗性基因，利用水稻多样性群体II（RDP-II）中的470份种质资源，在湖南省桃江县稻瘟病高发区的自然病圃中进行水稻苗期的抗病性鉴定，并通过全基因组关联分析（GWAS）鉴定稻瘟病的抗性相关位点，最终鉴定出25份苗期抗性较好的品种，可作为抗性育种材料。采用混合线性模型（MLM）对700 000个单核苷酸多态性（SNP）基因型和苗期的稻瘟病表型数据进行GWAS研究，在水稻基因组中鉴定了24个抗性关联位点，除4号和7号染色体外，在其余10条染色体上均有分布。在这些关联位点中，5个位点包含已克隆或定位的6个稻瘟病基因，其余19个位点是新的抗性位点。此外，通过对水稻亚群抗性规律分析发现，热带粳稻亚群的平均抗性水平最高，温带粳稻亚群的平均抗性水平最低。这些研究结果为分子辅助抗稻瘟病育种提供了分子标记，也为后续抗稻瘟病基因的克隆提供了基因组定位信息。        
关键词：水稻；稻瘟病；全基因组关联分析；数量性状位点
中图分类号：S435.111.4+1　　　　　  文献标志码：ADOI：10.3969/j.issn.1007-7146.2021.02.010

Abstract: Because the rice varieties with resistance genes are easy to be overcome by pathogens, it is necessary to further explore new rice blast resistance genes. We used 470 germplasm accessions of the Rice Diversity Group II (RDP-II) to evaluate their disease resistance at the rice seedling stage in a hotspot blast nursery (Taojiang, Hunan, China) and identified rice blast resistance loci using genome wide association study (GWAS). Twenty-five varieties with high levels of resistance at the seedling stage were identified which can be used as resistant breeding materials. The disease phenotypes and 700 000 SNP genotypes were used to perform GWAS with the MLM method. A total of 24 resistance-associated loci were identified in the rice genome, which were distributed on 10 chromosomes except chromosome 4 and 7. Among these loci, 5 loci were overlapped with 6 cloned or mapped genes related to rice blast resistance, and the remaining 19 loci were new loci. In addition, the analysis of the rice subpopulations showed that the average resistance level of tropical japonica subpopulation was the highest, and the lowest was the temperate japonica subpopulation. These findings provided DNA markers for molecular-assisted breeding of blast resistance and genomic location information for subsequent cloning of these genes.
Key words: rice; rice blast; genome-wide association study (GWAS); quantitative trait locus (QTL)
（Acta Laser Biology Sinica, 2021, 30(2): 163-169）