Genetic transformation of Tomato with three pathogenesis-related protein genes for increased resistance to Fusarium oxysporum f.sp. lycopersici

Fusarium wilt caused by Fusarium oxysporum f.sp. Lycopersici is one of the major obstacles to the production of tomato which causes huge losses in tomato products worldwide. In order to increase the tolerance to this disease, a triple structure containing PR1, chitinase and glucanase genes controlled by 35S promoter was transferred to tomato. Eight days after planting on pre-culture medium, explants were inoculated by Agrobacterium tumefaciens strain LBA4404 containing the aforementioned plasmid. When the regenerated shoots grew to 2-3 cm, they were cut and transferred to rooting medium.The plantlets were then transferred to pots filled with a soil mixture of peat moss and perlite for further acclimatization. The putative transgenic plant lines were analyzed by multiplex PCR and the transcription of the transgenes was confirmed by RT-PCR method using the specific primers. The estimated value for the frequency of the simultaneous transfer of chitinase, glucanase and PR1 genes to tomato was 2.7%. Protein extracts of transgenic plants expressing chitinase, glucanase and PR1 genes inhibited in vitro hyphal growth of F. oxysporum f.sp. lycopersici. Compared with non-transgenic control plants, despite some alterations in chlorophyll content no other morphological changes were observed in transgenic plants. The total content of chlorophyll “a” and “b” in transgenic plants were 31.8 and 36.2 % higher than that of control plants, respectively, which may be attributed to metabolic changes due to simultaneous expression of three transgenes.