ZmNPFs和ZmNRT2.1调节玉米根系氮素吸收的乙烯信号应答及其调控机制

Improving the utilization efficiency of fertilizer and exploring the mechanism of high-efficiency utilization of fertilizer are conducted, which will be of great significance to achieving the strategy of chemical fertilizer reduction and synergism in China. Currently, nitrogen fertilizer management and ethylene (ethephon) regulating plant growth and phenotype are important parts of high yield and high efficiency cultivation system in maize production. However, the regulation of nitrogen uptake by ethylene has been studied in focusing on agronomic characteristics in maize, and its regulatory mechanism is lack of study in depth. Here, maize varieties including Zhengdan 958 and Xianyu 335 and transgenic plants including over-expression and mutant of ZmACS7, ZmNPFs and ZmNRT2.1 will be selected as tested materials, while ethephon, ACC and AVG will be exogenously applied, and the experiments will be conducted in a long-term nitrogen location field and the growth chamber. It will be explore the regulation mechanism of ethylene on root development and nitrogen uptake character in maize roots responsed to different levels of nitrogen supplication. Moreover, over-expression and mutant of ZmACS7, ZmNPFs and ZmNRT2.1 will be used to analyse the expression of ZmNPFs and ZmNRT2.1 and nitrogen absorption characteristics in maize roots, meanwhile ethylene accumulation dynamics and signal expression abundance will be verified. Thus, gene-expression arrays have generated in over-expression and mutant of ZmACS7, ZmNPFs and ZmNRT2.1 combined with ACC/AVG application, and transcription expression profiles will be investigate in ethylene regulating nitrogen uptake and transfer. It is necessary and critical to explore the molecular mechanism in ZmNPFs and ZmNRT2.1 interacting with the key components of ethylene signal transduction or its response factors. Finally, signal transduction network will be constructed for ethylene regulating nitrogen absorption and transport. This research is of great significance to reveal the mechanism of ethylene regulating nitrogen high-efficiency absorption and utilization in maize, and provide a theoretical basis for the rational application of ethylene in maize production.

氮肥运筹与乙烯（乙烯利）调节生长是我国玉米丰产高效栽培技术体系的重要组成部分。但乙烯对玉米氮素吸收调控研究仅局限在农艺特征上，其调控机制缺乏深入研究。项目拟以郑单958、先玉335及ZmACS7、ZmNPFs与ZmNRT2.1过表达和突变体等为材料，结合乙烯利、ACC和AVG施用，利用田间氮素长期定位与室内模拟相结合，研究乙烯对根系响应氮素过程根系构型与氮素吸收特征的调控；分析不同遗传材料中ZmNPFs与ZmNRT2.1表达、氮素吸收特征和乙烯动态积累及其信号表达丰度；解析ZmACS7、ZmNPFs与ZmNRT2.1过表达和突变体材料响应氮素及添加ACC/AVG的表达谱，阐明乙烯信号转导元件或响应因子调控ZmNPFs与ZmNRT2.1表达的分子机制，构建乙烯调控氮素吸收的信号转导网络。研究对揭示乙烯在玉米高效吸收利用氮素中的调控作用具有重要意义，为乙烯在玉米生产上合理应用提供了理论基础。

氮肥运筹与乙烯（乙烯利）调节生长是我国玉米丰产高效栽培技术体系的重要组成部分。但乙烯对玉米氮素吸收调控研究仅局限在农艺特征上，其调控机制缺乏深入研究。项目针对研究目标开展研究工作，阐明了乙烯在田间和控制条件下调控玉米根系构型和氮素吸收、转运的作用效应和提高氮肥利用效率的栽培学机制；解析了乙烯通过调控生长素转运和信号途径中ZmPINs、ZmIAAs/ZmARFs等关键基因的表达，调控下游细胞伸长相关基因，影响根系构型的分子机制；阐释了乙烯通过转录级联调控途径调控硝酸盐转运蛋白ZmNPFs等基因表达，影响玉米的氮素吸收的调控机制；构建了乙烯参与调控根系构型及氮素吸收的信号转导和转录调控网络。研究结果丰富了乙烯在玉米高效吸收利用氮素中的调控机制理论，为乙烯在玉米生产上合理应用实现增产增效提供了理论依据。