Zhang Wenjun, Lukaszewski Adam J, Kolmer Jim, Soria Marcelo A, Goyal Sham, Dubcovsky Jorge
Department of Plant Sciences, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
Theor Appl Genet. 2005 Aug;111(3):573-82. doi: 10.1007/s00122-005-2048-y. Epub 2005 May 24.
Chromosome 7E from Lophopyrum ponticum carries a valuable leaf rust resistant gene designated Lr19. This gene has not been widely used in common wheat breeding because of linkage with the yellow pigment gene Y. This gene tints flour yellow, reducing its appeal in bread making. However, a high level of yellow pigment is desirable in durum wheat breeding. We produced 97 recombinant chromosomes between L. ponticum transfer 7D.7E#1 and its wheat homoeologues, using the ph1b mutation that promotes homoeologous pairing. We characterized a subset of 37 of these lines with 11 molecular markers and evaluated their resistance to leaf rust and the abundance of yellow pigment. The Lr19 gene was mapped between loci Xwg420 and Xmwg2062, whereas Y was mapped distal to Xpsr687, the most distal marker on the long arm of chromosome 7. A short terminal 7EL segment translocated to 7A, including Lr19 and Y (line 1-23), has been transferred to durum wheat by backcrossing. The presence of this alien segment significantly increased the abundance of yellow pigment. The Lr19 also conferred resistance to a new durum leaf rust race from California and Mexico that is virulent on most durum wheat cultivars. The new durum lines with the recombinant 7E segment will be useful parents to increase yellow pigment and leaf rust resistance in durum wheat breeding programs. For the common wheat breeding programs, we selected the recombinant line 1-96, which has an interstitial 7E segment carrying Lr19 but not Y. This recombinant line can be used to improve leaf rust resistance without affecting flour color. The 7EL/7DL 1-96 recombinant chromosome did not show the meiotic self-elimination previously reported for a 7EL/7BL translocation.
来自海滨麦草的7E染色体携带一个名为Lr19的重要抗叶锈病基因。由于该基因与黄色素基因Y连锁，它在普通小麦育种中尚未得到广泛应用。该基因会使面粉变黄，降低其在面包制作中的吸引力。然而，在硬粒小麦育种中，高水平的黄色素是可取的。我们利用促进同源配对的ph1b突变，在海滨麦草转移7D.7E#1及其小麦同源染色体之间产生了97条重组染色体。我们用11个分子标记对其中37个品系的一个子集进行了表征，并评估了它们对叶锈病的抗性和黄色素的含量。Lr19基因被定位在Xwg420和Xmwg2062位点之间，而Y基因被定位在Xpsr687的远端，Xpsr687是7号染色体长臂上最远端的标记。一个包含Lr19和Y的短末端7EL片段易位到7A染色体上（品系1 - 23），已通过回交转移到硬粒小麦中。这个外源片段的存在显著增加了黄色素的含量。Lr19还对来自加利福尼亚和墨西哥的一种新的硬粒小麦叶锈病菌系具有抗性，该菌系对大多数硬粒小麦品种具有毒性。带有重组7E片段的新硬粒小麦品系将成为硬粒小麦育种计划中增加黄色素和抗叶锈病能力的有用亲本。对于普通小麦育种计划，我们选择了重组品系1 - 96，它有一个携带Lr19但不携带Y的中间7E片段。这个重组品系可用于提高叶锈病抗性而不影响面粉颜色。7EL/7DL 1 - 96重组染色体没有表现出先前报道的7EL/7BL易位所具有的减数分裂自我消除现象。
