Optimal research on Agrobacterium-mediated transformation systems of tomato(Lycopersicon esculentum).

The conditions for regeneration and transformation of tomato mediated by Agrobacterium tumefaciens were studied with the aim of optimizing the transformation protocol.Factors of different genotypes,culture media,age and type of explants,plant expression vectors and select systems were investigated.Results show that after 2 d pre-culture,2 d co-culture and 2-4 weeks of selective culture with 75-100 mg·L-1 kanamycin,the best transformation efficiencies,51.4% and 37.5%,could be obtained when 7-d old cotyledon or 13-d old hypocotyl were used as explants and cultured on Murashige and Skoog(MS) media supplemented with 1.0-2.0 mg·L-1 zeatin(ZT) and 0.1-0.2 mg·L-1 indolylacetic acid(IAA).The transformation frequencies were significantly higher when p2301 and pBI121 containing kanamycin-resistant gene were used as expression vectors,compared with p1301 vector,which contained hygromycin-resistant gene.