Introduction of Bt cry1Ah gene into sweet sorghum (Sorghum bicolor L. Moench) by Agrobacterium tumefaciens-mediated transformation.

【Objective】 The aim of the study is to establish a high frequency and steady Agrobacterium tumefaciens-mediated transformation system of sweet sorghum,and validate the insecticidal function of a novel Bt cry1Ah gene in the transgenic plants.【Method】Using the callus induced from immature inflorescence as transformation recipients,the codon optimized Bt cry1Ah was transferred into sweet sorghum varieties BABUSH and MN-3025 via Agrobacterium-mediated transformation.The obtained regenerative plants were identified by PCR,RT-PCR analysis,and their herbicide resistance,the expression of aim protein and insect-resistant identification were also analyzed.【Result】After gradient selection with Biolaphos,a total of 66 regenerated plants were produced from 336 agroinfected calli in these two sweet sorghum varieties.Among these plants,22 PCR positive transformed plants of 8 independent transformation events were obtained,and the average transformation efficiency was 2.38%.The transcription of cry1Ah gene in the T0 transgenic sweet sorghum plants was further confirmed by RT-PCR.The Bt proteins could be detected by western blotting and ELISA assay in five transgenic plants,which showed different expression levels in a range of 1.93 ng?g-1 FW to 165.69 ng?g-1 FW,with an average of 87.50 ng?g-1 FW.Additionally,the results of bioassay indicated that two of the five transgenic plants displayed high insect-resistance to Ostrinia furnacalis.【Conclusion】An Agrobacterium-mediated genetic transformation system of sweet sorghum was established by using the callus derived from immature inflorescence as the recipients.The resulted T0 generation transgenic sweet sorghum plants with cry1Ah showed high insect-resistance to Ostrinia furnacalis.Further investigations on the genetic stability of cry1Ah in different transgenic lines and generations are undergoing.