Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
Theor Appl Genet. 2014 Mar;127(3):573-86. doi: 10.1007/s00122-013-2240-4. Epub 2013 Dec 4.
Stagonospora nodorum glume blotch (SNG), caused by the necrotrophic fungus Stagonospora nodorum, is one of the economically important diseases of bread wheat (Triticum aestivum L.). Resistance to SNG is known to be quantitative and previous studies of a recombinant inbred line (RIL) population identified a major quantitative trait locus (QTL) for resistance to SNG on the short arm of chromosome 3B. To localize this QTL (QSng.sfr-3BS) with high resolution, we constructed a genetic map for the QTL target region using information from sequenced flow-sorted chromosomes 3B of the two parental cultivars 'Arina' and 'Forno', the physical map of chromosome 3B of cultivar 'Chinese Spring' and BAC-clone sequences. The mapping population of near-isogenic lines (NIL) was evaluated for SNG resistance in field infection tests. NILs segregated for disease resistance as well as for plant height; additionally, we observed a high environmental influence on the trait. Our analysis detected a strong negative correlation of SNG resistance and plant height. Further analysis of the target region identified two linked loci associated with SNG resistance. One of them was also associated with plant height, revealing an effect of QSng.sfr-3BS on plant height that was hidden in the RIL population. This result demonstrates an unexpectedly high genetic complexity of resistance controlled by QSng.sfr-3BS and shows the importance of the study of QTL in mendelized form in NILs.
小麦颖枯病(SNG)由坏死型真菌禾旋孢腔菌引起,是影响小麦生产的重要病害之一。对 SNG 的抗性是数量性状,前人对重组自交系(RIL)群体的研究表明,3B 染色体短臂上存在一个控制 SNG 抗性的主效数量性状位点(QTL)。为了对该 QTL(QSng.sfr-3BS)进行高分辨率定位,我们利用两个亲本品种“Arina”和“Forno”的已测序流式分选染色体 3B 的信息、3B 染色体物理图谱和 BAC 克隆序列,为 QTL 目标区域构建了遗传图谱。利用近等基因系(NIL)群体在田间感染试验中对 SNG 抗性进行了评估。NIL 对疾病的抗性和株高均有分离;此外,我们还观察到该性状受到环境的强烈影响。我们的分析发现 SNG 抗性和株高之间存在强烈的负相关。对目标区域的进一步分析确定了与 SNG 抗性相关的两个连锁位点。其中一个位点也与株高相关,表明 QSng.sfr-3BS 对株高有影响,而这一影响在 RIL 群体中被掩盖了。这一结果表明,QSng.sfr-3BS 控制的抗性具有极高的遗传复杂性,也表明了在 NIL 中以 Mendelian 形式研究 QTL 的重要性。