Molecular cytogenetic identification of nullisomy 5B induced homoeologous recombination between wheat chromosome 5D and barley chromosome 5H.
Molecular cytogenetic identification of nullisomy 5B induced homoeologous recombination between wheat chromosome 5D and barley chromosome 5H.
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DOI：
10.1139/g04-096
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发表时间：
2005-02
期刊：
影响因子：
3.1
通讯作者：
S. Taketa;T. Awayama;M. Ichii;Makoto Sunakawa;T. Kawahara;K. Murai
中科院分区：
文献类型：
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作者：
S. Taketa;T. Awayama;M. Ichii;Makoto Sunakawa;T. Kawahara;K. Murai
大麦‘新黄金’(NG)的5H染色体携带一个在小麦背景下加速抽穗的基因(S)。为了将NG大麦的早穗基因(S)导入小麦基因组，我们尝试通过5B缺体来诱导小麦与NG 5H染色体之间的同源重组。利用小麦第5群染色体非整倍体群体间的系统杂交，获得了缺体5B、三体5A、单体5H植株(2n=42)。用35H特异性扩增标记对656株自交F2代植株进行了重组子筛选。筛选出12株(1.8%)小麦-大麦5H重组体。其中5个是不活的或不育的，其余7个是可育的，进行了子代测试。用荧光原位杂交和C显带的细胞学分析表明，7个后代系中有6个是5D和5H染色体长臂之间的真正同源重组体，而另1个不是大麦端粒异常的重组体。6个细胞学证实的重组系仅包括2个类型(每个3个系)，它们是由两个侧翼标记以相同的远端间隔交换而来的互换产物。一种类型有一个小的5HL片段移位到5DL末端，另一种类型的小末端5DL片段移位到5HL末端。在后一种类型中，易位大麦切段的物理长度在品系之间略有不同。本研究获得的同源重组体可用于进一步的染色体操作，将一个带有早熟基因(S)的5HL间隔区小片段导入小麦。限制性重组体的优先出现与小麦和大麦染色体之间的同源关系进行了讨论。
Chromosome 5H of Hordeum vulgare 'New Golden' (NG) carries a gene(s) that accelerates heading in a wheat background. To introduce the early heading gene(s) of NG barley into the wheat genome, we attempted to induce homoeologous recombination between wheat and NG 5H chromosomes by 5B nullisomy. A nullisomic 5B, trisomic 5A, monosomic 5H plant (2n = 42) was produced from systematic crosses between aneuploid stocks of wheat group 5 chromosomes. A total of 656 F2 plants produced by self-fertilization were screened for recombinants by a PCR assay with 3 5H-specific amplicon markers. Twelve plants (1.8%) were selected as putative wheat-barley 5H recombinants. Five of them were inviable or sterile and the remaining 7 were fertile and subjected to the progeny test. Cytological analyses using fluorescence in situ hybridization and C-banding revealed that 6 of the 7 progeny lines are true homoeologous recombinants between the long arms of chromosomes 5D and 5H, but that the other one was not a recombinant having an aberrant barley telosome. The 6 cytologically confirmed recombinant lines included only 2 types (3 lines each), which were reciprocal products derived from exchanges at the same distal interval defined by two flanking markers. One type had a small 5HL segment translocated to the 5DL terminal, and the other type had a small terminal 5DL segment translocated to the 5HL terminal. In the latter type, the physical length of translocated barley segments slightly differed among lines. Homoeologous recombinants obtained in this study should be useful for further chromosome manipulation to introgress a small interstitial 5HL chromosome segment with the early heading gene(s) to wheat. Preferential occurrence of restricted types of recombinants is discussed in relation to homoeologous relationships between wheat and barley chromosomes.