光和细胞分裂素在调控植物的生长发育过程中扮演重要角色。已有的研究表明细胞分裂素与光信号途径在调控植物的生长发育过程中存在互作，但是具体的分子机理并不清楚。通过筛选35S::ARR1ΔDDK:GR的抑制子rar（repressor of 35S::ARR1ΔDDK:GR）获得rar2突变体。rar2 35S::ARR1ΔDDK:GR在黑暗及光下生长时均表现出很强的DEX抗性，细胞分裂素处理增加RAR2蛋白表达，RAR2与ARR1蛋白体内存在互作，RAR2能够直接结合于SHY2基因的启动子区。因此，本项目重点进行以下三个方面研究工作：（1）揭示RAR2在光和细胞分裂素信号途径中调控初生根生长的分子机制；（2）探讨细胞分裂素对RAR2蛋白稳定性的影响并分析RAR2与ARR1体内互作是否依赖于光和细胞分裂素信号途径；（3）解析RAR2与ARR1在细胞分裂素和光信号途径中调控植物生长发育的信号网络。

Cytokinin and light play the important role in the regulation of various growth and developmental processes in plants.Previous studies showed that cytokinin interacts with light signaling pathway co-regulation plant growth.However the molecular basis and mechanism between cytokinin and light interaction is still unclear. In this proposal we isolated the DEX resistant rar2 mutant via genetic screening of repressor of 35S::ARR1ΔDDK:GR.rar2 35S::ARR1ΔDDK:GR mutant has longer hypocotyl and root with DEX treatment under light and dark condition.Cytokinin treatment increases RAR2 protein level expression.Using BiFC method, we find that RAR2 and ARR1 protein interacts in Arabidopsis protoplasts.The CHIP analysis showed that RAR2 can bind the promoter region of the SHY2 gene.So our proposal will focus on the three main respects,first,elucidating the mechanism for RAR2 regulating the root growth in cytokinin and light signaling pathway;second,demonstrating the relationship between RAR2 and ARR1;third, revealing the network controlled by ARR1 and RAR2 in cytokinin and light signaling pathway.