固醇合成途径关键基因SMT2、SMT3在植物免疫中的功能研究  

Function analysis of key genes SMT2 and SMT3 of sterol synthesis pathway in plant immunity

作　　者：钱虹萍 林金星[1,2] 崔亚宁 QIAN Hong-ping;LIN Jin-xing;CUI Ya-ning(Beijing Advanced Innovation Center for Tree Breeding by Molecular Design,Beijing Forestry University,Beijing 100083;College of Biological Sciences and Technology,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学高精尖创新中心,北京100083 [2]北京林业大学生物科学与技术学院,北京100083

出　　处：《电子显微学报》2021年第2期170-177,共8页Journal of Chinese Electron Microscopy Society

基　　金：国家自然科学基金资助项目(No.31530084);北京林业大学科技创新计划项目(No.BLX201911)。

摘　　要：植物固醇是细胞膜和膜筏的重要组分,与膜的稳定性密切相关。SMT2 (sterol methyltransferase 2)和SMT3 (sterol methyltransferase 3)是植物固醇合成途径中的关键基因,已有研究表明SMT2和SMT3基因在植物的生长发育中发挥重要作用。为探究SMT2和SMT3基因在植物免疫中的功能,采用细胞生物学、植物生理学等手段,分析smt2、smt3突变体在flg22诱导的防御反应中的作用。研究结果显示:与野生型相比,flg22诱导的smt2、smt3突变体产生的活性氧显著增加(高达50%);此外,flg22诱导smt2、smt3突变体中胼胝质沉积显著减少,减少量约为野生型的30%-40%。更为重要的是,flg22处理可以抑制野生型植株根的生长,而在smt2、smt3突变体中这种抑制作用相对减弱。以上这些结果表明,固醇在flg22诱导的植物免疫过程中起到了重要的作用,这一研究结果将为深入理解植物天然免疫的机制提供了新的依据。Plant sterols are important components of cell membrane and raft,which are closely related to the stability of membrane.SMT2(sterol methyltransferase 2)and SMT3(sterol methyltransferase 3)are key genes in the synthesis pathway of plant sterols,which have been shown to play an important role in plant growth and development.To explore the role of sterols in plant immune pathways,we analyzed the flg22-induced immune response in smt2 and smt3 mutant.The results showed that ROS rapidly accumulated in wild-type plants treated with flg22.However,in the smt2 and smt3 mutants,flg22-induced ROS production was significantly higher(up to 50%)compared with the wild type.The flg22-induced callose deposition was significantly impaired in the smt2 and smt3 mutants(down to 30%-40%)when compared with the wild type 24 h post-infiltration of active flg22,although no difference was detected in the plants infiltrated with H2O.More importantly,flg22 treatment inhibited root growth of WT plants,while this inhibition was relatively weakened in smt2 and smt3 mutants.These results suggest the key role of sterol homeostasis in flg22-induced plant defense responses,providing theoretical basis for further study on the mechanism of plant natural immunity.

关 键 词：植物固醇 植物免疫 活性氧 胼胝质 

分 类 号：Q942[生物学—植物学] Q945