基于基因组重测序信息构建玉米第5染色体的片段代换系
染色体片段代换系（CSSLs）是精细定位QTL的理想材料。构建CSSLs的常规方法是通过F1与轮回亲本多代回交，结合分子标记进行前景选择和背景选择，历时较长且耗费大量人力物力。本研究利用玉米自交系齐319与郑58杂交衍生的重组自交系群体，通过筛选剩余杂合体（RHL）以达到快速构建CSSLs的目的。在接近纯合的重组自交系群体中，结合基因组重测序信息扫描玉米第5染色体上的InDel位点，定点开发分子标记，筛选剩余杂合体进行自交快速获得了多个位点的染色体片段代换系。在玉米5号染色体的19,130,718bp-214,379,898bp区间内，共获得41个染色体片段代换系。两个染色体片段代换系位点间的间距为0.2Mb-26.4Mb，平均为2.5Mb。其中8个染色体片段代换系群体中只含有一个多态位点，为单片段代换系。本研究所建立的CSSLs可为玉米第5染色体上QTL的精细定位及功能分析提供强有力的支撑，并为玉米育种提供了一系列中间材料。
英文摘要:
Chromosome segment substitution lines (CSSLs) are excellent materials for QTL fine mapping and are mainly derived from multiple backcross between F1 progeny and recurrent parent, along with marker assisted foreground and background selection, which is laborious and time-consuming. In this study, we used a method discovering residual heterozygous line (RHL) in the recombinant inbred lines and CSSLs were produced after self-pollination within one year. Based on the re-sequenced data of maize genome through next generation sequencing, InDel markers were developed throughout chromosome 5 and 41 CSSLs were selected at average space of 2.5Mb from the 19,130,718bp to 214,379,898bp. The minimal space between adjacent CSSLs was 0.2Mb while the max was 26.4Mb. Eight single segment substitution lines were produced containing only one polymorphic sites. These CSSLs will be benefit for fine-mapping of QTLs located on chromosome 5 and also can achieve the development of plant molecular breeding from utilizing single gene to synthetically exploiting genome.
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