氮素（硝酸盐）可作为重要信号物质调控植物的根系发育，但菊花根系响应硝酸盐信号的具体机理尚不清楚。前期申请人发现MADS-box转录因子CmANR1响应硝酸盐信号通过生长素信号途径调控菊花不定根与侧根的发育。后期酵母双杂交试验证明，CmANR1可以与BTB-TAZ骨架蛋白CmBTL1相互作用。基因表达分析表明，CmBTL1基因能够响应受较高浓度硝酸盐诱导。前人研究发现，硝酸盐诱导的BTB-TAZ骨架蛋白BTs可与底物形成复合体通过各种信号途径调控植物生长发育进程。因此，我们推测在CmBTL1可能通过与CmANR1互作，调控其蛋白稳定性而影响菊花根系的发育。为了证实该猜想，我们拟利用Cell-free系统结合相关生化方法以及一系列转基因菊花材料，确定CmBTL1对CmANR1蛋白稳定性的影响，以及CmANR1对下游硝酸盐转运、同化基因等的表达调控，最终解析硝酸盐信号调控菊花根系发育的分子机理。

Nitrogen (in particular nitrate) is an essential macroelement necessary for the development and growth of plant. Nitrate plays an important signaling role on the root system development in plants, however, its specific mechanism is still unclear in chrysanthemum. In our previous studies, MADS-box transcription factor CmANR1 could mediate an auxin signaling pathway to promote adventitious root and lateral root development in chrysanthemum in response to nitrate signal. Subsequent yeast two-hybrid (Y2H) assays showed that a BTB-TAZ protein CmBTL1 interacted with CmANR1 protein. CmBTL1 could responded to the induction of a higher nitrate concentration. Previous studies revealed that nitrate-induced BTB-TAZ skeleton proteins BTs tended to form complexes with its targets, regulating the developmental processes in plants through various signaling pathways. Therefore, we speculate that nitrate-inducible CmBTL1 may regulate CmANR1 protein stability through their interaction, thereby affecting root development via nitrate signaling pathway in chrysanthemum. To verify this hypothesis, we will use cell-free system together with a series of biochemical methods and transgenic materials to confirm the effect of CmBTL1 on CmANR1 protein stability, as well as the regulation of CmANR1 on expression of nitrate transporters and assimilation genes, finally giving insights to the molecular mechanism of nitrate signal on regulating root development in chrysanthemum.