Purified lipid transfer protein LTP2 from barley applied on tobacco leaves eliminated symptoms caused by infiltration of Pseudomonas syringae pv. tabaci 153. Growth of the pathogen in leaves of transgenic tobacco plants was retarded when compared with non-transformed controls. The percentage of inoculation points that showed necrotic lesions was greatly reduced in transgenic tobacco (17-38% versus 78%) and the average size of these lesions was 61-81% that of control. The average total lesion area (necrosis and chlorosis) in the transgenic plants was also reduced (38% of control). Arabidopsis thaliana transgenic plants inoculated with P. syringae pv. tomato DC3000 also had lower percentages of necrotic lesions (22-38% versus 76%), a reduced average area for each lesion (53-67% of control), and a smaller total lesion area per inoculation (43% of control). These results further support the assignment of a defense role for LTPs and highlight their biotechnological potential.