Isatis Indigotica Transformed With Bivalent Expression Vector Harboring Both Bt And CpTI Genes Showed Enhanced Insect-resistance

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 band.The expression amount of anti-insects protein was detected by ELISA. The highest amount of CryIA(c) and CpTI were 436.33 ng/g and 158.31 ng/g respectively.Insect bioassay test showed that transgenic plants expressing high level of CryIA(c) and CpTI had significant inhibition to the growth of population of diamond-back moth (Plutella maculipennis Curtis), two lines could totally kill target insects and four lines could kill insects at different extent. 40% lines were of obviously insect-inhibition effects. There is no evident change of chemical components between wild type and transgenic plants.