PRSL1通过蛋白磷酸酶PP1调控拟南芥植株形态的分子机理

Protein phosphatase PP1 catalyzes about 1/3 dephosphorylation reactions in eukaryotes. Its specificity is dependent on the combination of PP1c with different regulatory subunits, therefore, uncovering the function mechanism of PP1 regulatory subunits is important. However, little is known about the regulatory subunits and their functions in plants. We found that a mutant of Arabidopsis PP1 regulatory subunit, prsl1-1, exhibits dwarfism with small and curled leaves, similar to those of topp4-1, a PP1 mutant we screened before. Based on this mutant, we plan to reveal the role of PRSL1 in regulating TOPPs by comparing the expression pattern, observing the localization of TOPPs, and screening substrates of PRSL1 and TOPP4. Furthermore, through observing the phenotype of mutants and transgenic lines and their responses to GA treatment, we will elucidate the molecular mechanism of PRSL1-TOPPs on modulating plant morphology and different function of 9 TOPPs in this process. This study will promote the research on the crucial function of PP1 in plants, and complete the recognition of plant cell signal transduction and regulatory mechanism of plant organ morphogenesis.

蛋白磷酸酶PP1催化真核生物中约1/3的去磷酸化过程，其功能特异性由催化亚基PP1c与不同的调节亚基结合决定，因此寻找并揭示调节亚基的作用机制意义重大。植物中PP1调节亚基的研究非常有限，调控机理更不清楚。本课题组发现拟南芥PP1调节亚基的突变体prsl1-1植株矮化，莲座叶狭小卷曲，与我们之前发现的PP1突变体topp4-1非常相似。本项目以该突变体为研究材料，拟通过表达模式比较、TOPPs定位观察、PRSL1与TOPP4共同底物的筛选等解析PRSL1调控TOPPs的作用模式；通过观察突变体和转基因植株表型及它们对外源GA的反应等揭示PRSL1-TOPPs调节植物形态的分子机理以及TOPP家族9个蛋白在其中的不同功能。该研究有助于推动植物中PP1蛋白磷酸酶的功能研究，促进人们对植物细胞信号转导过程和植物器官形态建成调节机理的深入认识。

蛋白磷酸酶PP1催化真核生物中约1/3的去磷酸化过程，因此研究其作用机制对深入认识植物生命活动的复杂调控过程有重要意义。本研究构建了拟南芥磷酸酶PP1家族多重突变体，发现9突变体表现出植株严重矮化，育性降低等多种表型。因此，拟南芥磷酸酶PP1家族成员在调节植物生长发育中发挥重要功能，且有很高的冗余性。还观察了8个基因的表达模式，为解析各基因独特的生物学功能提供依据。水稻中该家族同源基因敲除后也表现出纯合体植株矮小、开花延迟且不育，与拟南芥9突变体类似，外源施加GA可恢复其矮小表型，其体内GA合成酶基因表达改变，因此，推测该突变体内GA含量可能降低。此外，我们还得到该磷酸酶在玉米中的同源基因敲除突变体，并发现纯合突变体对NaCl和PEG6000处理更敏感， 对干旱耐受性增强。本研究为以后拟南芥、水稻和玉米中的该家族磷酸酶研究提供了宝贵的突变体材料并指出部分研究方向，有助于推动植物中该家族蛋白磷酸酶的功能研究。