In this project, two isolates of Xanthomonas campestris pv campestris were compared in the following conditions, 1. growth in NYG rich medium, and 2. growth in XVM1 minimal medium. Total proteins were extracted and trypsin digested. The nanoscale Liquid Chromatography was performed to separate tryptic peptides in a nanoAcquity system (Waters, USA) using 2D dilution technology. The digested peptides were analyzed in a Synapt G2 HDMS mass spectrometer (Waters, Manchester, UK) operated in the resolution mode of analysis and a resolving power of at least 20,000 full-width half-maximum (FWHM). All analyses were performed using a positive nanoelectrospray ion mode (nanoESI +). ProteinLynx Global Server (PLGS) version 2.5 (Waters, Manchester, UK) was used to process the MS data obtained from LC-MSE. For protein identification, the software embedded ion accounting algorithm was used. For the analysis of protein identification and quantification level, the observed intensity measurements were auto normalized by PLGS.