棉花化控栽培分子机制及轻简作物构建研究

缩节安（DPC）化控技术是棉花现行高效栽培的共性技术，但DPC对玉米等调控不显著。开展DPC调控棉花等生长发育的分子机制研究，构建易于DPC调控的轻简作物，将生物技术与化控技术结合对作物栽培理论发展与技术创新具有推动作用。项目以棉花、玉米和水稻为材料，结合体外重组与E.coli细胞工程体系，研究DPC对棉花等CPS酶活性的调节作用，分析DPC与GGPP、辅助因子Mg2+互作对CPS酶活性的调控机制；解析棉花等CPS蛋白及其与底物、DPC结合复合体的晶体结构，研究CPS酶活性中心的结合、催化与调控位点及其对DPC响应，构建CPS与DPC互作的分子模型；利用基因工程改造棉花等CPS与DPC互作调控位点，研究遗传改良CPS作物响应DPC的生化特征、分子应答及调控网络。研究为DPC在棉花等作物上高效应用提供理论基础，开拓了分子遗传改良与调节剂应用结合的新途径，丰富和发展了作物化控栽培理论与技术。

Mepiquat chloride (N, N-dimethylpiperidinium chloride, DPC) as an efficient and economic plant growth retardant is widely applied for cotton production, which has been as a common key technology for high-yield and high-efficiency cultivation in cotton. However, some corps such as maize and rice are insensitive to DPC application. Consequently, it is very necessary to explore the regulating target and molecular mechanism of DPC regulating cotton and other crops growth and development, and to construct easy-crop easily regulated by DPC, which will be benefited to develop the cultivation technology and theory of crop chemical control. Here, the project is conducted in cotton, corn and rice under field and growth chamber conditions. Based on in vitro recombination and E.coli cell engineering system, it will be studied on the regulation of DPC on cotton and others CPS enzyme activities, and analyzed the interaction mechanism between DPC and GGPP or enzyme cofactor Mg2+ for CPS enzyme activities. Moreover, the crystal structure of CPS protein and binding complex of CPS and GGPP or DPC will be analyzed, and the binding sites, catalytic sites and regulatory sites will be explored in CPS enzyme active center responded to DPC application. And then, the molecular model of interaction between CPS and DPC will be constructed. Otherwise, the CPS-edited maize and rice will be generated by using CRISPR-based gene editing to study the biochemical characteristics, molecular responses and regulatory networks of genetically modified CPS crops in response to DPC. The research will reveal t the docking mode of CPS-DPC and the mechanism of ligand-binding difference between CPSs and DPC. Importantly, this work will open up a new way to improve crop sensitivity to DPC by molecular improvement. It has important theoretical and application value to develop the cultivation technology and theory of crop chemical control in crops production.