Proteomic Analysis Of The Roots Of Ammopiptanthus Mongolicus In Response To Drought

Due to the change of global climate,massive alterations have happened to the environment where plants grow.Among all the abiotic stresses,drought did the greatest harm to plants,which seriously effected the growth,development,biological yield and distribution.Ammopiptanthus,which distributes the desert region of northwest of China,is a rare and endangered evergreen,broadleaf and super xerophytic shrub,belongs to the first batch of rare and endangered species in China.Because of its long growth in a severe environment,it has a very strong resistant capability.20%PEG6000 was applied to deal with Ammopiptanthus mongolicus roots,and 2-DE electrophoresis system was established by use of proteomics research method.Some differentially expressed proteins were also identified..The main results of this study are as follows:1.Optimized by extraction method of protein and loading quantity of sample for technical parameters,a 2-DE system was finally established for proteomics research of A.mongolicus roots:24cm,liner pH 4-7 IPG strips were adopted in IEF,12.5%gels concentration was used in SDS-PAGE,could detect about 2100 protein spots.2.Separating total protein from A.mongolicus roots under different drought stresses and using Image Master software to analyze the gels of different conditions,and 118 differentially expressed proteins were found.Through MALDI-TOF/TOF-MS analysis,97 protein spots were successfully identified.3.According to the different functions of proteins,97 protein spots were classified into 10 functional groups:free radical scavenging and antioxidant,protein synthesis,processing and degradation,metabolism,signal pathway,cell apoptosis,defense,ion and material transport,RNA processing,development related.Most of identified proteins were responsive proteins under drought stress.Many unknown proteins were also found,and these novel responsive proteins could provid new insights to the drought defense mechanism in plants.4.By analyzing the identified proteins function and metabolic pathways,we infer the drought stress could cause the distruction redox homeostasis in A.mongolicus roots,and results in oxidative burst,which in turn causes degradation of proteins and inhibition of protein synthesis.Because of oxyradical attacked,membrane system was destructed,signal pathway was affected,ion transmembrane was disrupted,and metabolism was inhibited.In order to resist drought stress,antioxidant proteins were over-expressed to eliminate active oxygen in roots.Through the expression of stress-related proteins,resisting the detriment of cellular components and repairing oxidative balance,the drought resistance of A.mongolicus was improved.