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

Abstract

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 biosafety of Bt crops. Promoter plays a key role to control foreign gene's expression feature. Previous study analysed the function of a promoter, which is cotton ADP-ribosylation factor 1 (arf1) gene's promoter, cloned in our laboratory. A plant expression vector pGBI121.A1Bt, which contained the Cry1A gene under the control of cotton arf1 promoter and the O factor, was constructed. Used as control, another vector pGBI121.4AB, carries Cry1A gene driven by P2E35S promoter, which is modified CaMV 35S promoter with doubled enhancers and a O factor. By Agrobacterium mediated transformation, tobacco was transformed by the two kinds of vectors, 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 the cotton boll.