Tomato proteome changes following soil application of Pseudomonas spp.

Two commercial biological products Proradix®Agro (Pseudomonas sp.) and Salavida (P. trivialis) were assayed on young tomato plants under Phytophthora infestans challenge, under greenhouse conditions. The products were water suspended following producer’s instruction and applied to the soil 6 days before the foliar inoculation with P. infestans. Late blight symptoms were observed 4 days after pathogen inoculation. Untreated plants appeared more infected than treated plants, but no statistically significant difference was found between treatments and controls or between the two products. However the application of each product led to a visible plant growth enhancement. A comparative study was carried out in order to highlight proteome differences among treated/untreated and inoculated/non inoculated plants. Total proteins were extracted from leaves collected 48h after pathogen inoculation and analysed by two-dimensional electrophoresis. The bioproduct application followed by the pathogen inoculation led to up/down-regulation of some protein spots which were different from those affected by the pathogen only. Mass-spectrometry analysis will be carried out in order to clarify if the observed modifications concern the activation of defence mechanisms or the observed plant growth promotion.