油菜素内酯调控玉米株型的转录因子基因网络解析

Brassinosteroids (BRs) play an essential role in the formation of agronomic traits including plant height, leaf angle and grain size during plant development. BR biosynthesis and signal transduction pathway has been well characterized in Arabidopsis, but much less in maize, an important food crop worldwide, and the genetic network controlling BR synthesis and signaling awaits further investigation. In particular, it’s paramount to dissect the tissue-specific genetic regulatory network underlying BR-dependent plant architecture formation in maize, which will lay a foundation for utilizing molecular design-based breeding approach to increase grain yield. In this study, we will first characterize the biological function of BR synthesis gene ZmD1 and BR signaling gene ZmBZR1 using the corresponding mutants Zmd1 and Zmbzr1, respectively. Then, these two mutants will be used for constructing tissue-specific expression networks of the transcription factor genes using RNA-seq technology, including roots, stems, leaves, ears and kernels. Furthermore, we will identify the transcription factors which are both plant height-specific and directly regulated by ZmBZR1 using the system of DEX-mediated protein nuclear import and then construct the corresponding network. Lastly, we will identify the allelic variations of the transcription factor genes from the natural variation population and the EMS-mutagenized population. Thus, we will be able to offer the theoretical and technological measures for molecular design-based plant architecture improvement.

油菜素内酯（BR）在植物发育过程中对株高、叶夹角、籽粒大小等性状的形成具有十分重要的作用。BR合成以及信号传导途径在拟南芥等模式植物中研究得比较清楚，但是在重要的粮食作物玉米中研究很少，其合成途径和信号传导途径的遗传调控网络尚未阐明，尤其是BR依赖的组织特异性转录因子基因网络的鉴定对玉米某个具体株型性状的改良具有关键作用。本项目在分离鉴定BR相关突变体的基础上验证BR合成关键基因（ZmD1）和信号传导关键基因（ZmBZR1）的生物学功能，然后以BR合成突变体(Zmd1)及BR信号传导突变体(Zmbzr1)为材料，首先构建玉米不同组织中BR调控的转录因子基因网络，进一步利用转录因子蛋白进核控制技术构建株高特异性且受ZmBZR1直接调控的转录因子基因网络，并以此为基础进一步挖掘鉴定相关转录因子基因的等位变异，为通过分子设计育种改良玉米株型提供理论和技术支撑。