Homoeologous Recombination: A Novel and Efficient System for Broadening the Genetic Variability in Wheat
Homoeologous Recombination: A Novel and Efficient System for Broadening the Genetic Variability in Wheat
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DOI：
10.3390/agronomy10081059
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发表时间：
2020-08-01
期刊：
影响因子：
3.7
通讯作者：
Gill, Bikram S.
中科院分区：
文献类型：
--
作者：
Koo, Dal-Hoe;Friebe, Bernd;Gill, Bikram S.
从野生小麦近缘种到面包小麦的基因转移仅限于同源重组。小麦染色体5 B长臂上的配对同源染色体1（Ph 1）基因的存在只允许同源染色体配对和重组，导致多倍体小麦的二倍体遗传。在此之前，我们鉴定了一个有效的同源异型配对启动子基因（Hpp-5 M（g））;它的载体染色体5 M（g）来自膝状山羊草，它的小麦同源异型染色体5D在Ph 1基因的存在下自由重组。在这项研究中，我们研究了在Ph 1缺失的情况下Hpp-5 M（g）对同源重组的影响。在Hpp-5 M（g）/ph 1bph 1b植物中，我们观察到全基因组范围内同源重组和多重交换（CO）的大量增加，包括已知重组被抑制的染色体近端区域中的CO断点。我们通过产生小麦-中间偃麦草罗伯逊易位（RobT T7BS.7S#3L）中存在的小麦条斑花叶病毒抗性基因Wsm 3的新重组体来测试Hpp-5 M（g）/ph 1bph 1b诱导的同源重组的效力。通过基因组原位杂交筛选T7BS.7S#3L和7 B的后代双单体，检测到6.5%的重组频率。与单独使用ph 1b诱导的同源重组观察到的重组频率0.06%相比，该重组频率高约100倍。研究结果表明，5 M（g）染色体促进了小麦与野生小麦近缘染色体的同源重组，有助于产生育种前材料，从而促进小麦作物改良。
Gene transfer from wild wheat relatives to bread wheat is restricted to homologous recombination. The presence of the Pairing homoeologous 1 (Ph1) gene in the long arm of wheat chromosome 5B allows only homologous chromosomes to pair and recombine, resulting in diploid inheritance of polyploid wheat. Previously, we identified a potent homoeologous pairing promotor gene(s) (Hpp-5M(g)); its carrier chromosome 5M(g)derived fromAegilops geniculataand its wheat homoeologous chromosome 5D freely recombined in the presence of thePh1gene. In this study, we investigated the effect ofHpp-5M(g)on homoeologous recombination in the absence ofPh1. InHpp-5M(g)/ph1bph1bplants, we observed a vast genome-wide increase in homoeologous recombination and multiple crossovers (CO), including CO breakpoints in proximal regions of the chromosomes where recombination is known to be suppressed. We tested the efficacy ofHpp-5M(g)/ph1bph1b-induced homoeologous recombination by producing new recombinants for the wheat streak mosaic virus resistance gene,Wsm3, present in the wheat-Thinopyrum intermediumRobertsonian translocation (RobT T7BS.7S#3L). A recombination frequency of 6.5% was detected by screening the progenies double monosomic for T7BS.7S#3L and 7B by genomic in situ hybridization. This recombination frequency was about 100-fold higher compared with the recombinant frequency of 0.06% observed by usingph1b-induced homoeologous recombination alone. Our results indicate that chromosome 5M(g)promotes homoeologous recombination between wheat and wild wheat relative chromosomes, which helps in the generation of pre-breeding materials thereby accelerating wheat crop improvement.