The plant binary expression vector pGBI121S4ABC carrying two insect resistance genes CryIA(c)-CpTI was constructed. The genes were transformed into the explants through Agrobacterium-mediated transformation. The rates of PCR positive for cotyledons of diploid and tetraploid Isatis indigotica were 14.75% and 16.67 % respectively.The resoults of Southern blot were Positive transgenic lines all showed single hybridization bands as expected (all single copy), while wild type showed no hybridization ba...