核糖体在植物生长发育过程中至关重要。拟南芥蛋白质精氨酸甲基转移酶AtPRMT3通过参与核糖体生物合成调控植物生长发育，其功能缺失突变体atprmt3-2呈现核糖体相关突变体共有的多效表型。为了阐明AtPRMT3参与核糖体生物合成及生长发育调控的分子机理，申请人所在实验室以atprmt3-2为材料，利用EMS诱变，筛选到atprmt3-2抑制子突变体sp1 (suppressor of atprmt3-2, sp1)。在sp1中，atprmt3-2引起的生长发育缺陷得到恢复，而rRNA前体加工缺陷未被恢复，说明SP1作用于rRNA前体加工下游参与植物生长发育调控。本研究以sp1为材料，综合利用遗传学、分子生物学、基因组学、生物信息学、蛋白质组学和生物化学等方法，研究SP1在响应核糖体生物合成失调的核仁应激反应中的作用，揭示SP1参与AtPRMT3介导的植物生长发育调控分子机理。

Ribosomes play essential roles in plant growth and development. Protein arginine methyltransferase 3 in Arabidopsis (AtPRMT3) regulates ribosome biogenesis and plant development. Loss-of-function mutant of atprmt3-2 shows pleiotropic phenotypes, which can be commonly observed in most ribosomal mutants. To elucidate the molecular mechanism of AtPRMT3 regulating ribosome biogenesis and plant development, we screened for suppressors of atprmt3-2 (sp) from an ethyl methanesulfonate (EMS) mutagenized pool of atprmt3-2 seeds, and obtained a suppressor of atprmt3-2 (sp1), which fully rescued the pleiotropic morphological phenotypes of atprmt3-2. In contrast, the disturbed pre-rRNA processing in atprmt3-2 was not rescued by sp1, indicating that the SP1 acts downstream of the pre-rRNA processing to regulate plant growth and development. In this project, we will uncover the function and underlying mechanisms of SP1 in nucleolar/ribosomal stress response and AtPRMT3-mediated plant development regulation.