Li Hao, Deal Karin R, Luo Ming-Cheng, Ji Wanquan, Distelfeld Assaf, Dvorak Jan
Department of Plant Sciences, University of California, Davis, Davis, CA, United States.
College of Agronomy, Northwest A&F University, Yangling, China.
Front Plant Sci. 2017 Dec 20;8:2163. doi: 10.3389/fpls.2017.02163. eCollection 2017.
Meiotic pairing between homoeologous chromosomes in polyploid wheat is inhibited by the locus on the long arm of chromosome 5 in the B genome. (genomes SS), the closest relative of the progenitor of the wheat B genome, is polymorphic for genetic suppression of Using this polymorphism, two major suppressor loci, and , have been mapped in is located in the distal, high-recombination region of the long arm of the chromosome 3S. Its location and tight linkage to marker makes a suitable target for introgression into wheat. Here, was introgressed into hexaploid bread wheat cv. Chinese Spring (CS) and from there into tetraploid durum wheat cv. Langdon (LDN). Sequential fluorescence hybridization and genomic hybridization showed that an segment with replaced the distal end of the long arm of chromosome 3A. In the CS genetic background, the chromosome induced homoeologous chromosome pairing in interspecific hybrids with but not in progenies from crosses involving alien disomic substitution lines. In the LDN genetic background, the chromosome induced homoeologous chromosome pairing in both interspecific hybrids and progenies from crosses involving alien disomic substitution lines. We conclude that the recombined chromosome harbors but its expression requires expression of complementary gene that is present in LDN but absent in CS. We suggest that it is unlikely that and , a paralog of located on wheat chromosomes 3A and 3B and chromosome 3D, are equivalent. The utility of for induction of recombination between homoeologous chromosomes in wheat is illustrated.
多倍体小麦中部分同源染色体间的减数分裂配对受到B基因组5号染色体长臂上的位点抑制。B基因组的祖先的近缘种（基因组为SS）在对该位点的遗传抑制方面具有多态性。利用这种多态性，在中定位了两个主要抑制位点，即和。位于3S染色体长臂的远端、高重组区域。它的位置以及与标记的紧密连锁使得成为导入小麦的合适目标。在这里，被导入六倍体面包小麦品种中国春（CS），并从那里导入四倍体硬粒小麦品种兰登（LDN）。连续荧光原位杂交和基因组原位杂交表明，一个带有取代了3A染色体长臂的远端。在CS遗传背景下，该染色体在与的种间杂种中诱导部分同源染色体配对，但在涉及异源二体代换系的杂交后代中不诱导。在LDN遗传背景下，该染色体在种间杂种以及涉及异源二体代换系的杂交后代中均诱导部分同源染色体配对。我们得出结论，重组染色体含有，但它的表达需要LDN中存在而CS中不存在的互补基因的表达。我们认为，位于小麦3A和3B染色体以及3D染色体上的的旁系同源基因不太可能是等同的。说明了在诱导小麦部分同源染色体间重组方面的效用。
