棉花arf1启动子驱动Cry1A基因在烟草中特异性表达研究

Specific Expression of Cry1A Gene Driven by Cotton arf1 Promoter in Tobacco

在新一代Bt作物以及Bt作物安全性研究方面,Bt毒蛋白在植物特定发育阶段的表达特性渐受关注。本研究构建了植物表达载体pGBI121.A1Bt,其携带棉花arf1启动子驱动Cry1A基因的表达盒,启动子后面有一个Ω序列;对照载体pGBI121.4AB携带P2E35S启动子(增强子加倍的修饰CaMV35S启动子)驱动Cry1A基因的表达盒,在启动子后面也有一个Ω序列。利用根癌农杆菌介导法,将植物表达载体pGBI121.4AB和pGBI121.A1Bt转化烟草,分别获得44株和42株转基因烟草再生植株。ELISA检测表明,在pGBI121.A1Bt转基因烟草的蒴果、蒴果壳、花瓣和叶中Cry1A基因的平均表达水平分别为pGBI121.4AB的1.5、1.5、1.4和0.3倍。棉花arf1启动子在烟草中表达,证明了该启动子在植物生殖器官中具有优势表达特性,为arf1启动子应用于转基因抗虫棉,在棉花蕾铃中优势表达Bt毒蛋白,提高转基因棉花蕾铃抗虫性的新一代抗虫棉研究提供了依据。

The expression of Bt toxin in certain plant developmental period, certain quantity or certain organ in the transgenic plant is an important study field both in new generation of Bt crops and biosafty of Bt crops. Promoter plays a key role to control foreign gene＇s expression feature. Previous study analyzed the function of a promoter, which is cotton ADP-ribosylation factor 1 （arf1） gene＇s promoter, cloned in our laboratory. A plant expression vector pGBI 121 .A 1Bt, which contained the Cry1A gene under the control of cotton arf1 promoter and the Ω factor, was constructed. Used as control, another vector pGBI121.4AB, carryies Cry1A gene driven by P2E35S promoter, which is modified CaMV 35S promoter with doubled enhancers and a Ω factor. By agrobacteria mediated transformation, tobacco was transformed by the two kinds of vector respectively. ELISA assay showed that the average expression level of the Cry1A gene in the capsule, capsular hull, petal and leaf of pGBI121.A1Bt transgenic tobacco plants was 1.5, 1.5, 1.4, and 0.3 times of the that of pGBI121.4AB transgenic tobacco plants. The results suggest that arf1 promoter could drive foreign gene expression well in plant propagation organs. Therefore, we think arf1 promoter could be applied in the development of new generation of Bt cotton, which has better cotton bollworm resistant effect for expressing more Bt toxin in cotton boll.