Comparative proteomic analysis of Arabidopsis thaliana roots between wild type and its salt-tolerant mutant

Two-dimensional electrophoresis (2-DE) showed the variation expression of Arabidopsis thaliana root proteins between wild type and its salt-tolerant mutant obtained from cobalt-60 γ ray radiation. Forty-six differential root protein spots were reproducibly presented on 2-DE maps, and 29 spots were identified by matrix assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MS). Fifteen protein spots corresponding to 10 proteins, and 14 protein spots corresponding to 9 proteins were constitutively up-regulated and down-regulated in the salt-tolerant mutant root. Bioinformatic analysis indicated that those differential proteins might be involved in the regulation of redox homeostasis, nucleotide metabolism, signal transduction, stress response and defense, carbohydrate metabolism, and cell wall metabolism. Peroxidase 22 might be a versatile enzyme and might play dual roles in both cell wall metabolism and regulation of redox homeostasis. Our work provides not only new insights into salt-responsive proteins in root, but also the potential salt-tolerant targets for further dissection of molecular mechanism adapted by plants during salt stress.