The Study On Rice Transformation Of Bt Gene And Breeding

Rice is one of the most important food crops in the world, whose safety production will have a significant affection on the food security and stable life of world people. At present, Rice diseases and insect pests are still the main limited factors for rice production. Rice bollworm is one of most harmful insects, which risks rice yields severely. So far, however, there is not an effective way to prevent this insect besides using chemical insecticide, which not only increases the cost of rice production, but also risks the health of world people and global ecology security. Furthermore, the germplasm resistance to insect is still not be finding in the practice of rice insect resistance breeding. Thus, transforming outer resistance genes to rice is thought to be the most effective way for prevent insect pest.In present study, Agrobacterium-midated tansformation method and "gene gun" method were used for rice transformation with a binary expression construct pCAMBIA1300 +Bt (designated Cry1Ac). Elite positive resistant lines were selected through system breeding method for rice breeding. The main results of this study are showed below.1. Japonica rice TP309 is used for transformation, and 60 lines with Agraobacterium method and 20 lines with gene gun method were generated. The results of PCR check for 53 independent lines showed: 41 lines were positive with the proportion of 77.3% in total tested lines, and 30 lines are positive in 35 lines of Agrobacterium transformants with the proportion of 87.5%. 11 positive lines /18 total (61.1%) lines were verified in gene gun transformant lines.2. The results of field artificial resistance test of transgenic plants indicated: T1 lies showed much resistance differences, part lines are highly resistance or sensitive, but there is a high resistance frequency for Agrobacterium transformant lines, and the resistance result is not ideal for gene gun lines. Surprisingly, the gene gun lines lost all resistance at T2 generation. Bt protein test for part Agrobacterium transformant lines showed, Bt protein is all expressed in all resistance lines, but there is not a difference for the content of Bt protein. 3. 27 lines with elite trait and high resistance were obtained through systemic resistance screening and directed selection for 3 years and 6 generations. And now one line C11 (the number of 2007, figure 3-1 and 3-2) from C12 line in 27 lines is selected which has little difference with its donor TP309, but highly resistant to bollworm.4. With cross method, the Bt gene of C11 were successfully introgressed into several present cultivars resistant to disease but sensitive to insect. At present, we got a set of elite lines resistant to both disease and insect, further selection and breeding work is in progress.In conclusion, a set of technology system for gene transformation to rice resistance breeding has been generated, and it will provide more technology supports for the study of engineering rice poly-resistance breeding.