全基因组关联研究和数量性状基因座定位揭示了热带玉米种质中与镰刀菌穗腐病抗性相关的基因组位点。
Genome-Wide Association Study and QTL Mapping Reveal Genomic Loci Associated with Fusarium Ear Rot Resistance in Tropical Maize Germplasm.
作者信息
Chen Jiafa, Shrestha Rosemary, Ding Junqiang, Zheng Hongjian, Mu Chunhua, Wu Jianyu, Mahuku George
机构信息
College of Agronomy, Synergetic Innovation Center of Henan Grain Crops and National Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, Zhengzhou 450002, China.
International Maize and Wheat Improvement Center, 06600 Mexico Distrito Federal, Mexico.
出版信息
G3 (Bethesda). 2016 Dec 7;6(12):3803-3815. doi: 10.1534/g3.116.034561.
Fusarium ear rot (FER) incited by Fusarium verticillioides is a major disease of maize that reduces grain quality globally. Host resistance is the most suitable strategy for managing the disease. We report the results of genome-wide association study (GWAS) to detect alleles associated with increased resistance to FER in a set of 818 tropical maize inbred lines evaluated in three environments. Association tests performed using 43,424 single-nucleotide polymorphic (SNPs) markers identified 45 SNPs and 15 haplotypes that were significantly associated with FER resistance. Each associated SNP locus had relatively small additive effects on disease resistance and accounted for 1-4% of trait variation. These SNPs and haplotypes were located within or adjacent to 38 candidate genes, 21 of which were candidate genes associated with plant tolerance to stresses, including disease resistance. Linkage mapping in four biparental populations to validate GWAS results identified 15 quantitative trait loci (QTL) associated with F. verticillioides resistance. Integration of GWAS and QTL to the maize physical map showed eight colocated loci on chromosomes 2, 3, 4, 5, 9, and 10. QTL on chromosomes 2 and 9 are new. These results reveal that FER resistance is a complex trait that is conditioned by multiple genes with minor effects. The value of selection on identified markers for improving FER resistance is limited; rather, selection to combine small effect resistance alleles combined with genomic selection for polygenic background for both the target and general adaptation traits might be fruitful for increasing FER resistance in maize.
由轮枝镰孢菌引起的玉米穗腐病(FER)是一种全球范围内影响玉米籽粒品质的主要病害。寄主抗性是防治该病最合适的策略。我们报告了全基因组关联研究(GWAS)的结果,以检测在三个环境中评估的一组818个热带玉米自交系中与增强的FER抗性相关的等位基因。使用43,424个单核苷酸多态性(SNP)标记进行的关联测试确定了45个SNP和15个单倍型与FER抗性显著相关。每个相关的SNP位点对病害抗性的加性效应相对较小,占性状变异的1-4%。这些SNP和单倍型位于38个候选基因内部或附近,其中21个是与植物对胁迫(包括抗病性)的耐受性相关的候选基因。在四个双亲群体中进行连锁图谱分析以验证GWAS结果,确定了15个与轮枝镰孢菌抗性相关的数量性状位点(QTL)。将GWAS和QTL整合到玉米物理图谱上,发现在第2、3、4、5、9和10号染色体上有8个共定位位点。第2和9号染色体上的QTL是新发现的。这些结果表明,FER抗性是一个复杂性状,由多个具有微小效应的基因决定。基于已鉴定标记进行选择以提高FER抗性的价值有限;相反,选择将具有小效应的抗性等位基因与针对目标和一般适应性性状的多基因背景的基因组选择相结合,可能有助于提高玉米的FER抗性。