植物为了应对土壤中不同氮素形态和浓度的不均匀分布，通常通过复杂的基因调控网络修正其侧根的发生，并提高对有效氮的感应和吸收效率。我们最新发现侧根的发生受根系生物钟 (root clock) 的决定，但氮信号是否通过调控根系生物钟来改变侧根发生尚不清楚。因此，本课题将在拟南芥相关研究的基础上，以水稻为研究对象，探讨根系生物钟对不同氮素信号的响应及发生模式，分析生长素运输、合成和信号转导在介导根系生物钟对氮素信号响应过程中的作用机制。同时，研究C端编码小肽 (CEP) 作为新颖的氮信号响应分子对根系生物钟的调节作用，以及CEP与生长素之间的互作关系。结果将有助于解析氮素信号调控根系发育的分子机制，为提高根系对外源氮素的感应和氮素利用效率及培育氮高效作物提供候选基因和新的技术途径。

Nitrogen (N) is the most important nutrient for plants. To perceive the external fluctuating availability of both N concentrations and forms, plants have developed complex regulatory transcriptional networks to adapt their lateral root organogenesis. Recently, we uncovered a new mechanism, “root clock”, for plant to pre-pattern lateral roots along the primary axis in the plant model Arabidopsis. This root clock may represent a general mechanism for plants to coordinate primary root growth with root branching in order to optimize the uptake of nutrients from the soil. To access this hypothesis, the oscillating pattern of the root clock in response to altered N conditions in the crop model rice will be determined in this proposed project. Meanwhile, the involvement of auxin transport, biosynthesis, and signaling transduction on regulating root clock for external N signal will also be tested. In addition, we will further investigated the effect of newly identified C-TERMINALLY ENCODED PEPTIDES (CEPs) on root clock and its interaction with auxin signaling. The integration of the data obtained from these experiments will clarify the role of “root clock”, a novel emerging mechanism, in translating the external N signal to developmental signal for root development in rice. It will also provide a foundation for the development of novel strategies to increase the root N acquisition efficiency under N-limited conditions.