[Genetic transformation of Bt gene into sorghum (Sorghum bicolor L.) mediated by Agrobacterium tumefaciens].

Sorghum (Sorghum bicolor L.) was one of the most important crops in the world next to wheat, rice, maize, soybean and barley. Using the callus derived from immature inflorescence as the recipients, we efficiently transformed sorghum varieties 115, ICS21B and 5-27 with the insecticidal Bacillus thuringiensis (Bt) cry1Ab gene carried in the T-DNA of binary vectors which contained hygromycin resistance gene and gus gene via Agrobacterium tumefaciens. After gradient selection with hygromycin, a total of 21 independent transgenic plant lines, 52 transgenic plants were regenerated, and the average stably transformation efficiency was 1.9%. The integration and transcription of cry1Ab gene in transgenic sorghum was confirmed by PCR analysis, Southern blotting and RT-PCR analysis. The Bt proteins were expressed in most transgenic plants with different level from plant to plant by Western blotting and ELISA assay. According to insect bioassay in laboratory, the transgenic plants with a relatively high level of Bt gene expression displayed insect-resistance to pink rice borer (Sesamina inferens).