Codominant PCR-based markers and candidate genes for powdery mildew resistance in melon (Cucumis melo L.)
Codominant PCR-based markers and candidate genes for powdery mildew resistance in melon (Cucumis melo L.)
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DOI：
10.1007/s00122-010-1483-6
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发表时间：
2011-01
影响因子：
5.4
通讯作者：
F. Yuste-Lisbona;C. Capel;M. Gómez-Guillamón;J. Capel;A. López-Sesé;R. Lozano
中科院分区：
文献类型：
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作者：
F. Yuste-Lisbona;C. Capel;M. Gómez-Guillamón;J. Capel;A. López-Sesé;R. Lozano
由Podosphaera xanthii引起的白粉病是甜瓜作物上的一种主要病害，该真菌的1号、2号和5号小种是南欧最常见的小种。基因型TGR-1551对这3个小种的抗性均由一对显性基因控制。xanthii。结合群体分离分析和扩增片段长度多态性（AFLP），我们发现了8个标记与这一显性基因连锁。选择的AFLP片段的克隆和测序允许开发6个共显性的基于PCR的标记，定位在连锁群（LG）V。这些标记的序列分析导致两个抗性基因，MRGH 5和MRGH 63，属于核苷酸结合位点（NBS）-亮氨酸丰富重复序列（LRR）基因家族的鉴定。QTL分析检测到Pm-R1- 2和Pm-R5两个QTL，Pm-R1- 2与1号和2号小种的抗性显著相关（LOD值分别为26.5和33.3;表型变异的53.6和61.9%），后者对5号小种具有抗性（LOD评分为36.8;表型变异的65.5%），已发现其分别与MRGH 5和MRGH 63基因共定位。结果表明，在LG V中鉴定出的NBS-LRR基因簇中含有抗稻瘟病菌1、2和5号生理小种的候选基因。xanthii。对其它抗性种质的鉴定结果表明，本文报道的共显性标记也与登记号WMR-29携带的Pm-w抗性基因连锁，证明了它们在甜瓜育种中作为基因分型工具的有用性。
Powdery mildew caused byPodosphaera xanthiiis a major disease in melon crops, and races 1, 2, and 5 of this fungus are those that occur most frequently in southern Europe. The genotype TGR-1551 bears a dominant gene that provides resistance to these three races ofP. xanthii. By combining bulked segregant analysis and amplified fragment length polymorphisms (AFLP), we identified eight markers linked to this dominant gene. Cloning and sequencing of the selected AFLP fragments allowed the development of six codominant PCR-based markers which mapped on the linkage group (LG) V. Sequence analysis of these markers led to the identification of two resistance-like genes, MRGH5 and MRGH63, belonging to the nucleotide binding site (NBS)-leucine-rich repeat (LRR) gene family. Quantitative trait loci (QTL) analysis detected two QTLs,Pm-R1-2andPm-R5, the former significantly associated with the resistance to races 1 and 2 (LOD score of 26.5 and 33.3; 53.6 and 61.9% of phenotypic variation, respectively), and the latter with resistance to race 5 (LOD score of 36.8; 65.5% of phenotypic variation), which have been found to be colocalized with the MRGH5 and MRGH63 genes, respectively. The results suggest that the cluster of NBS-LRR genes identified in LG V harbours candidate genes for resistance to races 1, 2, and 5 ofP. xanthii. The evaluation of other resistant germplasm showed that the codominant markers here reported are also linked to thePm-wresistance gene carried by the accession ‘WMR-29’ proving their usefulness as genotyping tools in melon breeding programmes.