Proteomic characterization of silicon-mediated resistance against Ralstonia solanacearum in tomato

Background and aims Silicon has an important role in enhancing resistance of plants against multiple environmental stresses including pathogen infection, but the mechanism is still not completely understood. In the present study, the role of Si-mediated resistance to Ralstonia solanacearum in tomato ( Solanum lycopersicum ) root was explored by a proteomics approach. Methods Treatments consisted of pathogen inoculation with or without 2.0 mM Si amendments, and two controls with or without 2.0 mM Si amendments. Proteins from the tomato roots with different treatments were extracted and identified by two-dimensional gel electrophoresis (2-DE) and liquid chromatography-mass spectrometry (LC-MS/MS). Results Fifty-three protein spots were identified at least two-fold differences in abundance on 2-DE maps under R. solanacearum inoculation and/or Si application. Among these proteins, 40 were significantly altered (6 were up-accumulated and 34 were down-accumulated) by R. solanacearum inoculation only. And 26 were altered (16 were increased and 10 were decreased) when Si was added to R. solanacearum -inoculated tomato plants. More than half of the altered proteins (62 %) were associated with energy/metabolism including glycolytic pathway and TCA cycle. Five proteins were grouped into defense-response, of which four were membrane-associated proteins. Conclusions These findings provide insights into molecular mechanisms responsible for Si-mediated resistance of tomato against R. solanacearum .