植物可利用铵作为氮源，满足生长发育过程中对氮素的需要。植物细胞中过多的铵会产生氨毒效应。因此控制铵吸收的AMT与控制同化的GS和GOGAT基因之间可能存在协同表达调控机制。杨树对不同供氮环境具有良好适应性，是研究包括木本在内的植物铵吸收同化分子机制的理想材料。本研究以杨树吸收同化铵的主要器官——根为材料，确定根部AMT、GS及GOGAT基因的表达模式并鉴定其功能；不同铵浓度、外源底物、酶抑制剂处理后，研究根部NH4+、Gln、Glu含量变化等对AMT、GS、GOGAT基因表达的调控机制及基因间协同表达调控机制；构建上述基因的过表达转基因植株及抑制剂处理，通过改变内源AMT、GS及GOGAT基因的表达量进一步验证上述机制；采用转录组学方法鉴定相关转录因子，研究其对AMT、GS及GOGAT基因的调控作用。整合上述内容揭示杨树根部铵氮吸收与同化过程中AMT、GS及GOGAT基因的协同表达调控机制

Ammonium can be used as a nitrogen source for plants, while the excessive accumulated ammonium is toxic to plant cell. Therefore, the expression of AMT gene and GS, GOGAT genes, which are responsible for ammonium absorption and ammonium assimilation respectively, requires a highly coordinated control in plant, however, its mechanism remains unclear. For the good adaptability to a variety of nitrogen conditions, we select Populus as an ideal model system for studying the molecular mechanisms of ammonium absorption and assimilation in woody plant. The main objectives include: identify the expression pattern of AMT, GS and GOGAT genes in Populus root which is the main organ to absorb and assimilate ammonium; investigate the regulatory mechanisms underlying the effects of different contents of NH4+, Gln, Glu on the expression of AMT, GS and GOGAT genes in root, by applying different ammonium, exogenous substrates and enzyme inhibitors; overexpress AMT, GS and GOGAT genes respectively and compare their responses with the control plant to verify the regulatory mechanisms; identify the transcription factors regulating the AMT, GS and GOGAT expression with the transcriptomic approach. Our research will shed new lights on the expression mechanisms of AMT, GS and GOGAT genes during ammonium absorption and assimilation process in Populus.