title: Identification of Arabidopsis salt and osmotic stress responsive proteins using two-dimensional difference gel electrophoresis and mass spectrometry.
abstract: Arabidopsis thaliana cell suspension cultures have been used to investigate the effects of salinity and hyperosmotic stress on plant cellular proteins. We show that 200 mM NaCl and 400 mM sorbitol treatments induce extracellular medium acidification in Arabidopsis cell cultures, a typical response of plant cells to salt and hyperosmotic stress. Using (35)S-labelled amino acids, we demonstrated that NaCl causes a transient suppression of de novo protein synthesis, from which the cells recover within 4 h. Changes in the abundance of cellular proteins 6 h post NaCl and sorbitol treatments were analysed by 2-DE. Of a total of 2,949 protein spots detected on the gels, 266 showed significant changes in abundance across five independent experiments. Using MALDI-TOF MS, we identified 75 salt and sorbitol responsive spots. These fall into 10 functional categories that include H(+) transporting ATPases, signal transduction related proteins, transcription/translation related proteins, detoxifying enzymes, amino acid and purine biosynthesis related proteins, proteolytic enzymes, heat-shock proteins, carbohydrate metabolism-associated proteins and proteins with no known biological functions.
authors.affiliation: Department of Biotechnology, University of the Western Cape, Bellville, Cape Town, South Africa.
authors.forename: Bongani K
authors.initials: BK
authors.lastname: Ndimba
authors.forename: Stephen
authors.initials: S
authors.lastname: Chivasa
authors.forename: William J
authors.initials: WJ
authors.lastname: Simon
authors.forename: Antoni R
authors.initials: AR
authors.lastname: Slabas
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D009997:Osmotic Pressure; D020543:Proteome / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D013012:Sorbitol / Q000494:pharmacology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013462:Sulfur Radioisotopes
chemical_list: D029681:Arabidopsis Proteins; D020543:Proteome; D013462:Sulfur Radioisotopes; D012965:Sodium Chloride; D013012:Sorbitol