Fine Mapping of a QTL qFLW6 Controlling Rice (Oryza sativa) Flag Leaf Width
YU Jin-Sheng1,*, LU Hong-Yu1,*, LI Bai3, XING Yuan-Hang1, JIANG Wen-Jing1, ZHU Xin-Feng1, LUO Qiu-Hong1, NI Shen2#
1 College of Advanced Agricultural Sciences, Zhejiang A&F University, Lin'an 311300, China; 2 State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Fuyang 311400, China; 3 Jiaxing Academy of Agricultural Sciences, Jiaxing 314001, China
摘要剑叶宽影响水稻(Oryza sativa)株型与光合效率,是水稻育种的重要指标之一。本研究在以'Kolayal'和'华占'分别为供体亲本和轮回亲本构建的染色体片段代换系中,发现了剑叶明显窄于双亲的株系,命名为'窄叶华占'。对该株系F2分离群体进行表型观察,通过图位克隆的方法定位剑叶宽QTL所在片段并对候选基因相对表达量进行了分析。F2极端表型单株混合测序显示,该剑叶宽QTL位于6号染色体,通过精细定位和关键交换单株比较测序,最终将第6号染色体上控制剑叶宽的位点(quantitative trait locus for flag leaf width on chromosome 6, qFLW6)定位于1.486 kb的区间;Os06g0647200为qFLW6候选基因,该基因有2个选择性剪切,其中Os06g0647200-2在'窄叶华占'中的表达量显著低于'华占'。本研究定位到了一个参与调控水稻剑叶宽的新基因Os06g0647200,为水稻剑叶大小与光合产量改良提供了有利的基因资源。
Abstract：Flag leaf width affects rice (Oryza sativa) plant type and photosynthetic efficiency, and is one of the important targets in rice breeding. In the chromosome segment substitution lines constructed by using 'Kolayal' and 'Huazhan' as donor and recurrent parents, it was found that the flag leaves of one certain line were significantly narrower than both parental lines, therefore named after 'narrow Huazhan'. The phenotype of the F2 segregation population of this line was observed, and the region of the QTL for the flag leaf width was located by map-based cloning and the relative expression of the candidate gene was analyzed. The array analysis of individuals with extreme phenotypes in the F2 segregation population showed that the QTL for flag leaf width was located on chromosome 6. Through fine mapping and comparative sequencing of critical recombinant individuals, quantitative locus for flag leaf width on chromosome 6 (qFLW6) was finally located in the 1.486 kb interval. As the candidate gene, Os06g0647200 had 2 alternative splicing forms, among which Os06g0647200-2 had a significantly higher expression level in the 'narrow Huazhan' than that in 'Huazhan'. This study identified a novel gene Os06g0647200 involved in regulating flag leaf width in rice, which provides valuable genetic resources for the improvement of flag leaf size and photosynthetic yield in rice.
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