玉米株高和穗位高的遗传基础与分子机制*

株高和穗位高是玉米重要育种性状,直接影响植株的养分利用效率及抗倒伏性,进而影响玉米产量。玉米株高和穗位高属于典型数量性状,目前通过数量性状位点(quantitative trait loci mapping,QTL)定位和全基因组关联分析(genome-wide association study, GWAS)等方法已挖掘到较多相关遗传位点,通过QTL精细定位及利用突变体克隆了一些调控株高和穗位高关键基因。但是由于各研究组所利用的群体类型和大小、标记类型和密度以及统计方法不同,所鉴定QTL差异较大,单个研究难以揭示玉米株高和穗位高遗传结构。早期QTL定位的结果多以遗传距离来展示,不同时期GWAS研究所使用参考基因组版本不同,这进一步增加了借鉴和利用前人研究结果的难度。首次将目前已鉴定株高和穗位高遗传定位信息统一锚定至玉米自交系B73参考基因组V4版本,构建了株高和穗位高性状定位的一致性图谱,并鉴定出可被多个独立研究定位的热点区间。进一步对已克隆玉米株高和穗位高调控基因进行总结与分类,揭示株高和穗位高性状调控机制,对深度解析株高和穗位高遗传结构、指导基因克隆和利用分子标记辅助选择优化玉米株高和穗位高性状均具有重要意义。

Progress on Genetic Analysis and Molecular Dissection on Maize Plant Height and Ear Height

Plant height and ear height are important agronomic traits of maize, which directly affect the nutrient utilization efficiency and lodging resistance of the plant, and ultimately affect the yield of maize. Plant height and ear height are typical quantitative traits, and quantitative trait loci (QTL) mapping and genome-wide association study (GWAS) have been used to mine the related genetic loci. Some key genes regulating plant height and ear height were cloned by fine-mapping or by using mutants. However, due to the differences in type and size of mapping populations, type and density of the markers and statistical methods used by different research groups, the identified QTL was divergent significantly, and it was difficult to reveal the genetic structure of plant height and ear height of maize by single study. The identified QTLs were mainly based on genetic maps at early stages, and the versions of maize reference genome were updated several times, which hampered the efficient utilization of previously identified QTLs. Here, the mapping information of plant height and ear height was normalized and integrated into the V4 version of the maize inbred line B73 reference genome, and a consistent physical map for plant height and ear height was constructed. Furthermore, the mapping hotspots of plant height and ear height were identified by combining the results from independent studies. The cloned genes regulating both traits were also summarized. This study is of great significance for the in-depth dissection of the genetic structure of plant height and ear height, as well as for aiding gene cloning and marker-assisted selection in molecular breeding.