The improvement of resistance to bacterial speck in transgenic tomato plants by Agrobacterium tumefaciens mediated transformation

The pto gene, responsible for resistance to Pseudomonas syringae pv. tomato, was transferred to tomato genotype Urfa-2 by the LBA4404 strain of A. tumefaciens harboring the plasmid pPTC8. The presence of nptII and pto genes in transgenic plants was proved by PCR analysis. Insertion of the pto gene into the genome of transgenic plants and expression of the gene were confirmed by southern and northern hybridizations, respectively. The pathogen P. syringae pv. tomato was applied to all leaves of transgenic and control plants. While typical bacterial speck symptoms developed on the leaves of control plants, the transgenic plants did not display any typical symptoms of bacterial speck upon inoculation with strains 1 and 0. Some of these transgenic plants had thicker leaves than the control plants and produced abnormal flowers. The pollen of transgenic plants was used for crossing with control plants to produce F1 transgenic lines. Fruits from crossed transgenic and control plants were obtained, and F1 seeds germinated on Murashige and Skoog medium in the presence of kanamycin have developed F1 seedlings.