ZmGRAS24调节玉米生长发育的生物学功能及其分子机理研究

The mechanization trend of modern agricultural production makes the contradiction of crop growth period conflict more prominent under the rotation cropping system. However, it will generally reduce the output by shortening the growth period. Therefore, it is of crucial importance to screen for gene resources with functions of short growth period and high yield. Previous studies found that heterologous overexpression of ZmGRAS24 gene led to the rapid growth of transgenic plants at seedling stage, early flowering and grain weight increase. This project will further study the biological function and molecular mechanism of ZmGRAS24 gene. Firstly, the temporal and spatial expression patterns and subcellular localization of this gene were studied. The gene will be transformed into maize by using CRISPR/Cas9 knockout and overexpression technology, and the biological function of the gene will be analyzed and compared with the heterologous overexpression phenotype. Second, the DNA binding sequence of the ZmGRASS24 protein will be identified, the gene expression and function of the sequence-controlled gene will be studied. Finally, the changes of transcriptome and proteome in maize, rice and Arabidopsis thaliana transgenic plants compared to their corresponding wild-type plants will be analyzed. The regulation network of the ZmGRAS24 gene will be analyzed by comparing the differences among species. This study will clarify the biological function of ZmGRAS24 in maize growth and development and its molecular regulation mechanism, and also the potential as a gene resource to shorten the growth period and increase yield. Therefore, the study is of great theoretical significance and application value.

现代农业生产的机械化趋势使轮作制度下作物生育期冲突的矛盾更突出，但生育期缩短一般会降低产量。因此，筛选生育期短且高产的基因资源至关重要。前期研究发现，ZmGRAS24基因异源过量表达导致转基因植株苗期生长迅速、早花和粒重增加。本项目将深入研究ZmGRAS24基因的生物学功能和分子机理。首先研究该基因的时空表达模式和亚细胞定位，利用CRISPR/Cas9基因敲除和过量表达技术，将该基因转化玉米，分析该基因的生物学功能，并与异源过量表达的表型进行对比。其次，鉴定该基因编码蛋白的DNA结合序列，研究结合序列调控的基因表达与功能。最后，分析玉米、水稻和拟南芥转基因植株与相应野生型的转录组和蛋白质组改变，比较物种间的差异，分析该基因的调控网络。本研究将明确ZmGRAS24基因在玉米生长发育中的生物学功能及其分子调控机理，阐明该基因作为缩短生育期且高产的基因资源的潜力，具有重要的理论意义和应用价值。

现代农业生产的机械化趋势使轮作制度下作物生育期冲突的矛盾更突出，但生育期缩短一般会降低产量，筛选生育期短且高产的基因资源至关重要。本项目研究了ZmGRAS24基因的生物学功能和分子调控，发现该基因在玉米苗期根中高表达，是具有转录激活活性、响应多种激素的转录因子。玉米突变体分析发现初生根根长显著降低，根数量显著减少，且侧根密度减少，影响地上部的生长；而过量表达植株表现为根系发达且长势更为旺盛，开花期稍提前2天左右，株高差异不大，但植株更健壮。组学分析发现，植物激素信号转导等途径显著富集，该基因导致赤霉素代谢与响应下降，而生长素合成基因显著升高、降解代谢基因显著下降，说明ZmGRAS24通过正调控生长素、负调控赤霉素信号促进玉米幼苗生长发育。将该基因在拟南芥、短柄草、水稻中过量表达，均表现出促进苗期生长、适度早花且粒重稍增加的表型，显示了在作物改良中较好的利用潜力。