玉米节根夹角遗传结构剖析及其关键基因的克隆

根系在土壤中的深层分布可提高玉米对水分和氮素的吸收，而节根夹角是决定玉米根系深扎的关键性状。但是目前玉米节根夹角的遗传研究较少，其分子遗传机制尚不清楚，还未有相关QTL被精细定位和克隆的报道。申请者前期利用连锁和关联分析共同定位到控制玉米节根夹角的QTL（qRA1-1）。本项目拟在此基础上，利用两个连锁群体和两个关联群体，在多个环境条件下结合连锁和关联分析定位玉米节根夹角的QTL，剖析玉米节根夹角的遗传结构。随后构建次级分离群体对主效QTL（qRA1-1）进行精细定位，结合关联分析快速获得候选基因。对候选基因在骨干自交系及其衍生系中进行重测序，通过单倍型分析和基因差异表达分析，挖掘与节根夹角相关的优良等位变异并验证功能。本项目的开展将阐明玉米节根夹角的分子遗传机制，为玉米根系的遗传改良、玉米资源高效利用和高产潜力的挖掘提供理论依据和优良的基因与种质资源。

In maize deeper rooting, which is mainly determined by crown root angles, plays an essential role in nitrogen and water acquisition from soil. However, few study on the genetic architecture of crown root angles has been performed, and the underlying mechanism remains to be elucidated. In our preliminary work, a major QTL (qRA1-1) for crown root angle is identified by joint QTL mapping and association analysis. In this study we aim to identify the major QTL for crown root angle using two bi-parental segregating populations and two association populations phenotypically evaluated in multi-environment. Furthermore, the candidate gene for QTL qRA1-1 will be cloned by integrating fine-mapping and association mapping strategies, and the favorite alleles will identified by haplotype analysis, the corresponding gene sequencing and expression analysis. These findings will contribute to understanding the genetic basis of crown root angles, and the identified genes and favorable alleles can be important genetic resources for developing maize cultivars tolerant to nitrogen and water deficiency.