玉米叶夹角主效位点qLA2-3克隆和功能分析

叶夹角与玉米株型、光合作用和耐密性密切相关。在前期研究中，我们选用2个在穗上叶片叶夹角存在显著差异的商业玉米自交系，构建了一套包括200个家系的重组自交系群体，在三个种植环境中检测到一个叶夹角主效QTL qLA2-3，并利用染色体片段代换系将该QTL精细定位至447 Kb染色体区间。根据玉米参考基因组，该区间含有12个候选基因。另外，构建了qLA2-3的一对近等基因系。本项目拟在上述基础上，将深入研究qLA2-3调控叶夹角机制，研究内容如下：（1）利用石蜡切片、透射电镜和扫描电镜等研究qLA2-3调控叶夹角大小的表型和细胞学基础；（2）构建分离群体，进一步精细定位和克隆qLA2-3，并利用转基因功能互补和等位测验确认候选基因；（3）借助细胞学、原位杂交、免疫印迹和转录组等手段探究qLA2-3调控叶夹角形成的分子机制和基因网络。预期结果将丰富玉米叶夹角调控网络，并为密植品种选育提供基因资源。

Leaf angle is closely related to plant architecture, photosynthesis, and density tolerance of maize. In the previous study, we selected two commercial maize inbred lines with significant differences in leaf angles above ears, and constructed a set of recombinant inbred lines consisting of 200 lines. A major leaf angle QTL, qLA2-3, was detected in three planting environments, and mapped to the 447 Kb chromosomal region by chromosome segment substitution lines. According to a maize reference genome, there are 12 candidate genes in this region. In addition, a pair of near-isogenic lines of qLA2-3 was constructed. In this research project, we will further explore the mechanism of qLA2-3 regulating leaf angle. The major issues are as follows: (1) The paraffin section, transmission electron microscopy, and scanning electron microscopy will be used to analyze the phenotypic and cytological basis of qLA2-3 regulation of leaf angle. (2) We will use near-isogenic lines to construct a segregating population for further fine mapping, and use transgenic functional complementarity and allelic tests to confirm candidate genes. (3) The cytology, in situ hybridization, western blotting, and transcriptome will be used to explore the molecular mechanism and regulatory network of qLA2-3 regulating the formation of leaf angle. The results enrich the regulation network of maize leaf angle, and provide genetic resources for the breeding of dense planting varieties.