In this project, a plant growth promoting bacteria (PGPB) Pseudomonas protegens MP12 will be used to test its capacity to colonize into grapevine plants in order to enhance the growth and increase the resistance to attacks of fungal phytopathogens of grapevine (Vitis vinifera) like Botrytis cinerea, Plasmopara viticola, Erysiphe necator. The project will be carried out in two years by University of Verona (UV) and CREA of Conegliano. In the first year UV and CREA will perform experimental assays to assess the capacity of the bacterium to colonize V. vinifera through the cell inoculation into in vitro micropropagated plantlets, using wild and GFP-tagged strains. After the inoculation, plantlets will be examined to verify the presence of the bacterium into the plant tissue by classical (i.e. plate counts) and molecular analysis (i.e. PCR analysis and in situ fluorescent method). Major plant growth parameters will be measured in colonized and control plantlets. Infection of leaves by B. cinerea will be done and disease level will be recorded. In the second year UV and CREA will perform in planta experimental assay using rooted vines. The bacterium will be inoculated into unrooted and rooted vines and subsequent plantation in pots and in field will be carried out. Development of roots and shoots, and the most important physiological parameters will be compared between inoculated and control grapevines. Assessment of strain colonization into rooted vines, infection of fungi (B. cinerea, P. viticola and E. necator) and disease level will be done. This project will provide important information for improving the knowledge of endophytic patterns of inoculated PGPB bacteria. Moreover, the project will furnish interesting data about the possibility to use the exogenous application of living bacteria in V. vinifera to enhance plant resistance against diseases. Such approach will be useful for reducing significantly the use of pesticides in vineyards.