Comparative Study On Membrane Proteins Of Sugar Beet M14 Line Under Salt Stress

Salt stress is a major abiotic stress in agriculture, more than 20% of the land and almost half of all irrigation land are affected by salt, looking for resistance to salt stress related proteins or genes to understand the mechanism of plant resistance to salt and it is very important to improve plant salt resistance, but also expect using molecular biology techniques to improve resistance of plants to salt stress.Sugar beet is a kind of glycophyte and has strong salt resistant ability. Sugar beet M14 line is a special variety and it consists of Beta vulgaris L and Beta corolliflora Zoss. It has drought resistance, cold resistance, resistant to salt and so on. It becomes rare materials to dig quality genes and proteins of sugar beet.Plant cells have many membrane systems which have specialized specific functions, including the plasma membrane proteins and various organelles membrane proteins, membrane proteins are communication interfaces in plant to perform cell exchange with the environment. Plant cell membrane protein in control many of the major cell functions, such as metabolites, ion transport, vesicles transportation, etc., It first to be hurt under salt stress, and the membrane proteins in plants play a crucial role in the process to resist salt stress, membrane proteins change will cause changes in cell morphology. So it has important significance to research on mechanism of membrane proteins under salt stress.Membrane proteins are more difficult to analyze than soluble proteins because of 2-D polyacrylamide gel electrophoresis separation is not appropriate for comprehensive mapping of membrane proteins, many hydrophobic proteins are not solubilized in the IEF sample buffer and precipitate at their isoelectric point. Low abundance proteins are beyond the LODs of standard proteomic techniques. ITRAQ technology is better technology to study of membrane protein, and can detect multiple samples and detection rate is higher.This test using the iTRAQ technology study leaf membrane protein of sugar beet M14 line under salt stress (0,200,400 mM NaCl) to perform quantitative proteomics analysis. Compareing the mass spectrometry information and search the non redundant sugar beet database using protein pilot software, identified for 279 proteins (unused score>1.3), including 178 proteins with quantitative information. Analyze protein (p< 0.05),55 differentially expressed proteins are defined as a ratio greater than 1.2 or less than 1.2. We analysis grand business of hydropathicity(GRAVY) according to the protein amino acid sequence information using online software, nearly 73% of the protein are hydrophilic protein, and about 25% of the protein are hydrophobic proteins. It indicates the most differences membrane proteins are soluble membrane protein. Analyze differences in membrane protein molecular mass and isoelectric point. Summarizes distribution shows that the protein molecular weight is concentrated between 20-30 kDa, isoelectric point is mainly distributed in pH5-7 and pH8-10.In order to further study salt response membrane proteins, according to the BLAST tools and annotation information in Uniprot as well as the information from relevant literature. Salt response membrane proteins are classified. Identification of differentially expressed membrane protein in leaves were divided into 9 classes, respectively is: transport (25%), photosynthesis(16%), metabolism (16%), signal transduction (11%), protein folding and degradation (9%), stress and defense(9%), protein synthesis (7%), transcription(4%), cell structure (2%). Results show that the transport proteins, metabolism related proteins and photosynthesis proteins account for larger proportion. Usually membrane proteins involved in ion, water and proteins transport.We found that most membrane proteins located in the plasma membrane, Golgi apparatus membrane, endoplasmic reticulum, chloroplast membrane and peroxisome membrane through bioinformatics analysis.