Abstract: In this experiment , the effects of different hormone concentration on shoot regeneration from cotyledon explants are investigated . The results show that MS medium supplied with 1.5 mg/L 6-BA and 0.2 mg/L IAA is the suitable shoot regeneration. The experiment on sensitivity of cotyledon to hygromycin B and carbenicillin shows that the suitable hygromycin concentration for selecting transgenic tissue is 20 mg/L and the carbenicillin concentration is 300 mg/L. Fused gene O₂₁ - O₁₄ - A₂₁ containing both type O and A FMDV is transferred into lettuce mediated by Ti plasmid of Agrobacterium tumafaciens. The results of PCR and PCR-Southern blotting indicated that the O₂₁ - O₁₄ - A₂₁ gene were successfully integrated into the genomes of some transformed lettuce plants. Expression of O₂₁ - O₁₄ - A₂₁gene in vtransformed lettuce plants was proved by RT-PCR analyses .

Key words: FMD epitopes