Genetic transformation of Tomato with three pathogenesis-relatedprotein 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 theproduction of tomato which causes huge losses in tomato products worldwide. In order to increase thetolerance to this disease, a triple structure containing PR1, chitinase and glucanase genes controlled by35S promoter was transferred to tomato. Eight days after planting on pre-culture medium, explants wereinoculated by Agrobacterium tumefaciens strain LBA4404 containing the aforementioned plasmid. Whenthe regenerated shoots grew to 2-3 cm, they were cut and transferred to rooting medium.The plantletswere 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 thetransgenes was confirmed by RT-PCR method using the specific primers. The estimated value for thefrequency of the simultaneous transfer of chitinase, glucanase and PR1 genes to tomato was 2.7%. Proteinextracts of transgenic plants expressing chitinase, glucanase and PR1 genes inhibited in vitro hyphalgrowth of F. oxysporum f.sp. lycopersici. Compared with non-transgenic control plants, despite somealterations in chlorophyll content no other morphological changes were observed in transgenic plants. Thetotal content of chlorophyll a and b in transgenic plants were 31.8 and 36.2 % higher than that ofcontrol plants, respectively, which may be attributed to metabolic changes due to simultaneous expressionof three transgenes.

Keywords:

Chitinase , Fusarium oxysporum , Glucanase , PR1 , Transgenic Tomato