Abstract: An efficient Agrobacterium-mediated transformation system for transferring Interleukin-2 gene (il-2) into tomato was developed by studying several factors that affect the frequency of shoot differentiation and the efficiency of Agrobacterium mediated transformation of explant tissues. Two Agrobacterium strains (EHA105 and C58C1), two types of explant (cotyledon and hypocotyls)and three vectors with different selectable markers (Kan^r, PPT^r and Hyg^r) were tested for their influences on transformation. Total 2018 cotyledon and hypocotyl explants from three tomato cultivars were transformed by co-cultivation with Agrobacterium, and 47 selective agent-resistant plants were obtained. 44 out of those were il-2 positive by PCR assay. PCR-Southern hybridization of the PCR-tested plants confirmed the PCR assay, indicating that the il-2 gene had been introduced into tomato.

Key words: interleukin-2 gene, Agrobacterium-mediated method, Lycopersicon esculentum, genetic transformation