Studies On The Transformation Of SUT Genes Into Cassava

The cassava is a very important food and energy plants in Euphorbiaceae family, in order to improve the transgenic efficiency in four mainly cultivars of cassava in China (NZ188、SC8、Arg7and TMS60444), the regeneration efficiency and the genetic transformation systems of these cultivars were optimized in this study. We also studied the genetic transformation of Sucrose transporter (SUT) in cassava. The transgenic plants were verified by PCR,RT-PCR and Southern Blot. The main results were as follows:1. The effects of different factors including genotypes, sucrose, IBA and AgNO3on the regeneration efficiency were studied. The results showed that there are significant differences in the capacities of somatic embryogenesis and organogenesis among the tested genotypes. The enlargements of axillary buds in NZ188, SC8and TMS60444in the dark condition were better than that of in the light conditions. Their induced frequencies of primary somatic embryos were more than80%, while Arg7grew better in light condition. The best medium for the induction of somatic embryogenesis and mature somatic embryos is using the medium containing25-30g/L sucrose. The induction frequency of adventitious shoots and the average shoot were improved significantly on the shoot organogenesis medium with4mg/L AgNO3and0.3mg/L IBA.2. According to the results of cocultivation with different Agrobacterium tumefaciens strains and antibiotic dose responses, the optimized conditions were established for the best transformation efficiency in cassava. Infect with the Agrobacterium strain LBA4404is better than GV3101. After cocultivation, the selection of transgenic cells using500mg/L Carbenicillin and20mg/L of hygromycin was better than other conditions. In order to ensure the success of the conversion and avoid blocking of plant regeneration process, we added antibiotics gradiently to the medium in the screening and the regenerating process.3. In the transformation of SUT gene using the optimization of genetic transformation system in these4varieties of cassava, we got8PCR positive transformed plants. Among them, there are5RT-PCR-positive transgenic plants and one SC8Southern Blot-positive transgenic lines. These results proved the feasibility of the optimization system.