利用多群体剖析玉米株高遗传机制及基因克隆

Maize plant height is closely related to biomass, lodging resistance as well as yield. At the same time plant height is a model for study the complex quantitative traits because of its high heritability and easy measurement in maize. For the genetic improvement of maize yield, dissecting genetic mechanism and cloning of key genes for plant height have potential significance. We developed 10 RILs (ROAM populations) with 14 typical inbred lines as parental materials. These germplasms were genotyped by high-density SNP markers and phenotyped in two years and 12 locations. We aslo mapped the plant height by three kinds of statistics methods (GWAS, JLM and SLM) , and JLM was our lab self exploitation joint analysis method. Our project plans are to systematically dissect the genetic architecture of maize plant traits and clone 1-2 key QTL by using the identified residual heterozygous family lines, and developing corresponding functional markers application for maize molecular breeding.

玉米株高与生物量、抗倒伏性及产量密切相关，同时株高遗传力高容易度量是复杂数量性状研究的模式性状。解析株高的遗传机制和克隆关键基因对玉米产量的遗传改良有重要意义。本课题拟用14个典型自交系作为亲本所构建的10个重组自交系群体（ROAM群体）为材料，结合两年12点的表型鉴定数据和覆盖全基因组的高密度分子标记，利用三种统计分析（全基因组关联分析，结合多群体连锁分析，单个群体连锁分析。其中第二种为本实验室自主开发）模型方法，深度解析玉米株高的遗传机制。利用剩余杂合群体精细定位克隆关键QTL 1-2个，并挖掘优良等位基因，开发相应的分子标记应用于玉米分子育种。

植物株型是影响玉米种植密度和产量的关键因素。然而，不同遗传背景下株型的遗传机制尚未完全阐明。在这里，对来自14个不同遗传背景的10个重组自交系群体10个株型相关的性状进行大规模表型分析，并解剖控制这些性状的遗传位点。研究发现，近800个QTL影响株型。前人证明的影响植物株型的关键发育基因，与本研究中的QTL存在共定位。一个新的株高QTL，qPH3，已经精确定位到600kb的基因组区域，其中有三个候选基因位于该区域。进一步利用精细定位实验，将候选基因进行了克隆，该基因为GRMZM2G177220，该基因编码一个exo70家族蛋白。同时对该候选基因进行了亚细胞，酵母双杂与转基因的初步分析。这些结果深入了解控制植物结构的遗传机制，将有助于选择理想的玉米育种提供服务。