Combined linkage and association mapping identifies a major QTL (qRtsc8-1), conferring tar spot complex resistance in maize
Combined linkage and association mapping identifies a major QTL (qRtsc8-1), conferring tar spot complex resistance in maize
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DOI：
10.1007/s00122-016-2698-y
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发表时间：
2016-06-01
影响因子：
5.4
通讯作者：
Xu, Yunbi
中科院分区：
文献类型：
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作者：
Mahuku, George;Chen, Jiafa;Xu, Yunbi
控制玉米焦斑复合体抗性的一个主效QTL(qRtsc8-1)，在890个玉米自交系中出现的频率为3.5%。焦斑复合体(TSC)是一种高度破坏性的玉米病害，在美国一些国家发现。鉴定TSC抗性种质资源，阐明抗性遗传机制，是利用寄主抗性管理该病的关键。利用玉米Illumina maizeSNP50珠片中含有56K SNPs的基因数据，对890份玉米优良自交系在不同环境中的抗性进行了全基因组关联分析。通过对来自不同抗性和感病亲本的三个双亲群体的连锁分析，验证了Gwas的结果。在第2、7、8号染色体上分别检测到3个TSC抗性基因座(-log10(P)>；5.99)。在玉米8.03号染色体上检测到一个主效抗病基因座，命名为qRtsc8-1。QRtsc8-1在三个独立的双亲群体中被证实，它可以解释所观察到的TSC表型变异的18-43%。QRtsc8-1区域出现频率为3.5%的罕见单倍型使TSC抗性增加14%。候选基因分析表明，一个富含亮氨酸重复序列的受体样蛋白(LRR-RLKs)基因家族可能是qRtsc8-1的候选基因。鉴定和定位一个控制TSC抗性的主效基因，为精细定位qRtsc8-1和开发玉米TSC抗性改良的功能标记奠定了基础。据我们所知，这是第一个与TSC抗性有关的主要QTL的报道。
A major QTL ( qRtsc8 - 1 ) conditioning resistance to tar spot complex of maize and occurring at a frequency of 3.5 % across 890 maize inbred lines.Tar spot complex (TSC) is a highly destructive disease of maize found in some countries in America. Identification of TSC resistant germplasm and elucidating the genetic mechanism of resistance is crucial for the use of host resistance to manage this disease. We evaluated 890 elite maize inbred lines in multiple environments and used genome wide association analysis (GWAS) with genotypic data from Illumina MaizeSNP50 BeadChip containing 56 K SNPs to dissect the genetics of TSC resistance. GWAS results were validated through linkage analysis in three bi-parental populations derived from different resistant and susceptible parents. Through GWAS, three TSC resistance loci were identified on chromosome 2, 7 and 8 (-log10 (p) > 5.99). A major quantitative resistance locus (QTL) designated qRtsc8-1, was detected on maize chromosome bin 8.03. qRtsc8-1, was confirmed in three independent bi-parental populations and it accounted for 18-43 % of the observed phenotypic variation for TSC. A rare haplotype within the qRtsc8-1 region, occurring at a frequency of 3.5 % increased TSC resistance by 14 %. Candidate gene analysis revealed that a leucine-rich repeat receptor-like protein (LRR-RLKs) gene family maybe the candidate gene for qRtsc8-1. Identification and localization of a major locus conditioning TSC resistance provides the foundation for fine mapping qRtsc8-1 and developing functional markers for improving TSC resistance in maize breeding programs. To the best of our knowledge, this is the first report of a major QTL for TSC resistance.