EXPRESSION OF THAUMATIN II GENE IN CARROT FOR IMPROVED PATHOGEN RESISTANCE

Transgenic carrot (Daucus carota L.) plants expressing a thaumatin II protein were obtained by Agrobacterium-mediated transformation. Embryogenic cultures of ‘Nantskaya 4’ were transformed by disarmed super virulent Agrobacterium strain CBE21 harboring pBIThau35 plasmid. The presence of the thauII gene was confirmed by PCR, and the expression of the thaumatin II protein in primary transgenic plants was confirmed by Western blot analysis. Positive T₀ carrot plants were self-pollinated and T₁, T₂ and T₃ seeds were produced. Resulting seeds were further selected for antibiotic resistance and the inheritance and expression of thauII gene was evaluated by PCR and Western blot. From these, five groups of T₂ and T₃ progenies of two T₀ lines were analyzed for the enhanced tolerance to the foliar and root pathogen Fusarium avenaceum. Among tested carrot plants, both T₂ and T₃ transgenic progenies of 40-61 line showed fairly strong resistance against pathogen.