Pasquariello M, Ham J, Burt C, Jahier J, Paillard S, Uauy C, Nicholson P
John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK.
RAGT Seeds, Grange Road, Ickleton, Essex, CB10 1TA, UK.
Theor Appl Genet. 2017 Jan;130(1):91-107. doi: 10.1007/s00122-016-2796-x. Epub 2016 Sep 24.
Phenotyping and mapping data reveal that chromosome intervals containing eyespot resistance genes Pch1 and Pch2 on 7D and 7A, respectively, do not overlap, and thus, these genes are not homoeloci. Eyespot is a stem-base fungal disease of cereals growing in temperate regions. Two main resistances are currently available for use in wheat. Pch1 is a potent single major gene transferred to wheat from Aegilops ventricosa and located on the distal end of chromosome 7D. Pch2, a moderate resistance deriving from Cappelle Desprez, is located at the end of 7AL. The relative positions of Pch1 and Pch2 on 7D and 7A, respectively, suggest that they are homoeoloci. A single seed decent recombinant F7 population was used to refine the position of Pch2 on 7A. New markers designed to 7D also allowed the position of Pch1 to be further defined. We exploited the syntenic relationship between Brachypodium distachyon and wheat to develop 7A and 7D specific KASP markers tagging inter-varietal and interspecific SNPs and allow the comparison of the relative positions of Pch1 and Pch2 on 7D and 7A. Together, phenotyping and mapping data reveal that the intervals containing Pch1 and Pch2 do not overlap, and thus, they cannot be considered homoeloci. Using this information, we analysed two durum wheat lines carrying Pch1 on 7A to determine whether the Ae.ventricosa introgression extended into the region associated with Pch2. This identified that the introgression is distal to Pch2 on 7A, providing further evidence that the genes are not homoeoloci. However, it is feasible to use this material to pyramid Pch1 and Pch2 on 7A in a tetraploid background and also to increase the copy number of Pch1 in combination with Pch2 in a hexaploid background.
表型分析和定位数据显示，分别位于7D和7A染色体上含有抗眼斑病基因Pch1和Pch2的染色体区间并不重叠，因此，这些基因不是同祖基因座。眼斑病是温带地区谷类作物的一种茎基部真菌病害。目前小麦中有两种主要的抗性可用。Pch1是一个从节节麦转移到小麦的强效单主基因，位于7D染色体的远端。Pch2是源自卡佩勒·德普雷的中度抗性基因，位于7AL的末端。Pch1和Pch2分别在7D和7A上的相对位置表明它们是同祖基因座。利用单粒传重组F7群体来细化Pch2在7A上的位置。针对7D设计的新标记也使得Pch1的位置得到了进一步确定。我们利用短柄草与小麦之间的共线性关系，开发了7A和7D特异性KASP标记，用于标记品种间和种间单核苷酸多态性，并比较Pch1和Pch2在7D和7A上的相对位置。表型分析和定位数据共同显示，含有Pch1和Pch2的区间并不重叠，因此，它们不能被视为同祖基因座。利用这些信息，我们分析了两个在7A上携带Pch1的硬粒小麦品系，以确定节节麦的渗入是否延伸到了与Pch2相关的区域。这表明该渗入位于7A上Pch2的远端，进一步证明了这些基因不是同祖基因座。然而，在四倍体背景下利用这种材料将Pch1和Pch2聚合在7A上，以及在六倍体背景下结合Pch2增加Pch1的拷贝数都是可行的。
