Yeo F K S, Bouchon R, Kuijken R, Loriaux A, Boyd C, Niks R E, Marcel T C
Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708PB, 6700 AJ Wageningen, the Netherlands.
Department of Plant Science and Environmental Ecology, Faculty of Resource Science and Technology, University Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia.
Mol Breed. 2017;37(4):45. doi: 10.1007/s11032-017-0624-x. Epub 2017 Mar 16.
Partial resistance quantitative trait loci (QTLs) and against isolate 1.2.1 were previously mapped in seedlings of the mapping populations Steptoe/Morex and Oregon Wolfe Barleys, respectively. In this study, QTL mapping was performed at adult plant stage for the two mapping populations challenged with the same rust isolate. The results suggest that and are effective only at seedling stage, and not at adult plant stage. The cloning of several genes responsible for partial resistance of barley to will allow elucidation of the molecular basis of this type of plant defence. A map-based cloning approach requires to fine-map the QTL in a narrow genetic window. In this study, and were fine-mapped using an approach aiming at speeding up the development of plant material and simplifying its evaluation. The plant materials for fine-mapping were identified from early plant materials developed to produce QTL-NILs. The material was first selected to carry the targeted QTL in heterozygous condition and susceptibility alleles at other resistance QTLs in homozygous condition. This strategy took four to five generations to obtain fixed QTL recombinants (i.e., homozygous resistant at the or QTL alleles, homozygous susceptible at the non-targeted QTL alleles). In less than 2 years, was fine-mapped into a 0.2-cM genetic interval and a 1.4-cM genetic interval for . The strongest candidate gene for is a phospholipid hydroperoxide glutathione peroxidase. Thus far, no candidate gene was identified for .
部分抗性数量性状位点（QTL）及对分离株1.2.1的抗性先前已分别定位在作图群体Steptoe/Morex和俄勒冈狼大麦的幼苗中。在本研究中，对这两个用相同锈菌分离株接种的作图群体在成株期进行了QTL定位。结果表明，[相关QTL]仅在幼苗期有效，在成株期无效。克隆几个负责大麦对[锈菌]部分抗性的基因将有助于阐明这种植物防御类型的分子基础。基于图谱的克隆方法需要在狭窄的遗传窗口内对QTL进行精细定位。在本研究中，[相关QTL]通过旨在加速植物材料开发并简化其评估的方法进行了精细定位。用于精细定位的植物材料是从为产生QTL近等基因系而培育的早期植物材料中鉴定出来的。首先选择该材料使其在杂合状态下携带目标QTL，而在纯合状态下携带其他抗性QTL的感病等位基因。该策略需要四到五代才能获得固定的QTL重组体（即，在[相关QTL]等位基因上纯合抗性，在非目标QTL等位基因上纯合感病）。在不到两年的时间里，[相关QTL]被精细定位到一个0.2厘摩的遗传区间，[另一相关QTL]被精细定位到一个1.4厘摩的遗传区间。[相关QTL]的最强候选基因是一种磷脂氢过氧化物谷胱甘肽过氧化物酶。到目前为止，尚未鉴定出[另一相关QTL]的候选基因。
