Proteomics Analysis of Xanthomonas citri subsp. citri Response to American Basil (Ocimum americanum L.) Oil

Abstract

Xanthomonas citri subsp. citri (XCC) is the causative agent of the citrus canker, one of the most devastating diseases of citrus wordwide. It decreases the production and quality of citrus fruits and can spread rapidly. The American basil (Ocimum americanum L.) oil was found to inhibit growth of XCC. In this study, the inhibitory mechanism of basil oil against XCC was investigated. The proteomics analysis of XCC which grown in the presence of basil oil at the level of the sub–minimum inhibitory concentration (sub–MIC; 125 μg/ml) was performed. Total proteins isolated from treated Xanthomonas citri subsp. citri were separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE), tryptic in–gel digestion and identified by LC–MS (GeLC–MS). GeLC–MS analysis identified 8,551 proteins which are significantly differential expression, 172 of which were expressed in accordance with survival of XCC. Analysis based on STITCH database, 28 out of 172 proteins were involved in bacterial response to antibiotics. Seventeen proteins were predicted to associate with streptomycin treatment via histidine metabolism, shikimate pathway and tRNA synthesis.