拟南芥SMO2通过rRNA前体加工调控植物发育的分子机制

植物生长发育过程受自身遗传和外界环境的严格调控。前期我们鉴定了一个拟南芥器官变小的突变体smo2，smo2表现出生长发育异常和ABA敏感的表型。初步研究表明SMO2可能与甲基转移酶SIF1和rRNA结合蛋白APUM23形成一个复合体，参与rRNA前体加工，然而rRNA前体加工介导植物发育和环境信号的机制仍不明确。本项目拟通过分析SMO2复合体各亚基的亚细胞定位、体内互作、以及突变体表型，明确植物体内存在SMO2复合体；分析rRNA前体累积和甲基化修饰的变化，解析SMO2复合体参与rRNA前体加工的可能机制；研究逆境胁迫对SMO2复合体各亚基间互作、基因和蛋白表达，以及SMO2复合体各亚基变化对逆境胁迫下植物rRNA前体加工、信号通路和生长发育的影响，阐明SMO2复合体在植物发育应答逆境信号中的作用。本研究将为阐明植物发育的调控及其对逆境胁迫响应的机制提供新的见解，为其优化改良提供依据。

Plant growth and development is tightly controlled by genetic information and environmental cues. Previously, we have characterized an Arabidopsis mutant, small organ 2 (smo2) that was defective in plant development and ABA sensitivity. Our preliminary results have revealed that SMO2 may form a complex with a methyltransferase SIF1 (SMO2 Interaction Factor 1) and ribosome RNA (rRNA) binding protein APUM23 to regulate pre-ribosomal RNA processing. However, how pre-ribosomal RNA processing mediates plant development and environmental cues remains to be investigated. In this proposal, we will analyze the subcellular localization, in-vivo interaction, and mutant’s phenotypes to confirm the existence of SMO2 complex in plants. Next, the changes of pre-ribosomal RNA abundance and methylation modification of rRNA will be examined to investigate the underlying mechanism of SMO2 complex controlling pre-ribosomal RNA processing. Protein interaction and expression of SMO2 complex subunits will be detected under abiotic stresses; pre-ribosomal RNA processing, signaling pathway and developmental program will be examined when the activities of SMO2 complex are altered under abiotic stresses, finally clarifying the role of SMO2 complex linking plant development and environmental cues. Our study will provide the insightful views for the regulation of plant development and adaptation toward abiotic stress, which will benefit for plant design.