Abstract: Using sterile tomato cotyledons as explants and kanamycin-resistant NPTⅡ as a marker gene, the ThaumatinⅡ gene which encodes a plant sweet protein from Thaumatococcus daniellii has been introduced into the tomato genome by Agrobacterium-mediated transformation. As a result, 10 independent tomato transgenic lines were acquired. The introduction of the foreign gene was confirmed by PCR for the expected specific bands. Furthermore, one transgenic line was shown by two copies of integration on Southern blotting analysis. Taken together, all the above results have indicated that the ThaumatinⅡ gene has integrated into the genome of tomato. This represents the first step to finally obtain marker-free transgenic tomatoes expressing plant sweet protein ThaumatinⅡ.

Key words: tomato, plant sweet protein, ThaumatinⅡ gene, genetic transformation