氮素对茶树产量与品质具有十分重要的作用。研究低氮胁迫下茶树氮素吸收的机制，对氮高效茶树培育及防止茶园氮肥施用带来的环境问题，都有着重要的作用。模式植物中的研究表明，高亲和氮素转运蛋白（High Affinity Transport Systems, HATS）在缺氮条件下的氮素吸收中发挥了重要作用。HATS对低氮条件下茶树氮素吸收有多大贡献？低氮条件下，起作用的主要的HATS组分及其作用机制又是什么呢？课题组前期，已克隆得到7个HATS基因的全长cDNA序列。在此基础上，本课题以两组氮效率截然不同的茶树F1子代个体为试验材料，采用集群分离分析（BSA）原理，分析二组氮效率差异群体在低氮胁迫下的转录表达差异，结合氮吸收效率值找出与茶树低氮下氮吸收有关的HATS基因，明确HATS基因对低氮胁迫的响应及组织表达特性，转基因拟南芥验证其功能，构建基因调控网络，揭示茶树低氮环境下氮效率调控机制。

Nitrogen plays a crucial role on the production and quality of tea. Understanding the mechanisms of nitrate uptake from the soil in response to nitrogen deficiency is an important step on the way to breed the high nitrogen use efficiency (High-NUE) cultivars in tea, and to prevent negative effects of nitrogen fertilizers on the environment. It has been indicated that high-affinity nitrogen transporters play an essential role in model plants under low nitrogen condition. The high affinity nitrogen transport systems (HATS) acts at low NO3 concentrations and hence is important in N limited conditions. However, how much do HATS contribute to root NO3 uptake activities in nitrogen-deficiency tea plants? What’s the main component of HATS in tea roots under low nitrogen conditions and how does it function?. In our previous studies, 7 transcripts (3 CsAMT1 and 4 CsNRT2) belonging to HATS gene families have been found from tea root transcriptomic. Meanwhile, the full-length cDNA sequences of these genes have been cloned. Here, two bulked populations of tea are generated from F1 progeny showing contrasting phenotype in nitrogen use efficiency under N-deficiency conditions, and the root transcriptomic of two bulked samples under N-deficiency conditions will be analyzed by RNA-seq. Combined with N uptake efficiency determined by Continuous Flow Analytical System(CFA), Bulked-segregant analysis (BSA) will be applied to identify some essential HATS genes associated with N uptake under low nitrogen conditions. Furthermore, the tissue expression patterns and the temporal expression patterns in response to low nitrogen conditions of identified HATS genes will be analyzed by QT-PCR. Finally, transgenic Arabidopsis will be established to verify their function. By combining correlation analysis and gene co-expression network analysis, A gene network for regulating the NUE will be constructed. We will uncover the regulation mechanism of NUE under low nitrogen condition in tea.