Expression Analysis Of Bt Protein In The Backcross Progenies Of Transgenic Insect-resistant Maize

Maize is one of the world’s most important food and feed crops, currently the acreage of maize is second only to wheat and rice and it has a rising trend in the recent years and plays an important role in agricul tural production. But every year the infection of plant diseases and insect pests have brought people a huge economic losses; to some extent the traditional methods such as field management and chemical control could inhibite the threat of pests and diseases, but those methods are time-consuming and will pollute the environment, there existed significant limitations. It’s reported that the expression of Bt protein exist the spatial and temporal differences in the insect resistance maize lines, as the Bt protein expression is not always in a high levels, however the high expression of Bt protein is an important prerequisite of insect-resistant transgenic plants and transgenic maize often leads to a production reduction in quality, useing the backcrossing method to cultivate the Bt protein expression stability and good in agronomic traits maize become the main trend. In this study, this research provides important theoreticals and experimental basis for rapid detection of backcrossing progenies of transgenic insect resistant maize, Bt protein expression analysis in transgenic insect-resistant maize and provided new germplasms in cultivating new varieties of transgenic insect-resistant maize, we got the main results as follows:1. Though the herbicide resistance screening, we found that the transgenic insect-resistant positive maize material have no blade decline phenomenon, however the leaves in the control group have been basically dead; the results of PCR detections shows that the positive plants both have the 820bp Bt gene fragments PCR bands and the 1955bp bar gene fragments PCR bands, it showed that the gene Bt gene and bar receptor genes have been successfully introduced into the receptor plants.2. The expression analysis of Bt in the backcross progenies of transgenic insect-resistant maize and inbred lines shows that the Bt gene can express normally in the backcross progenies of transgenic maize, there is an insignificant different expression in different backcross progenies, and this is possible because of the sites which the fragment to insert to or the copy numbers of the gene fragment, we didn’t detected the expression in the inbred lines.3. From the dynamic Bt protein expression in the backcross progenies at the same growth period of different tissues, we saw that the content of Bt protein expression in the backcross progenies of different organizations from high to low was as follows: Leaves>immature seeds>Filigree>seed husk. Bt protein content both higher than 0.5%4. From the dynamic Bt protein expression in the backcross progenies at different growth periods of laeves tissue, we knew that the Bt content in leaves showed a rising trend from seedling stage to silking stage when reached the peak at the silking stage and then declined gradually.5. Through the analysis of agronomy characters in the backcross progenies of transgenic insect-resistant maize, we knew that BC1F1 had significant difference changes with common maize in height of stem and 100-grain weight, it shows that We need successive backcross to cultivate the Bt protein expression stability and good in agronomic traits maize.In summary, in this study we establishmented a rapid Bt gene detection system, we analysed the Bt protein specific expression in the backcross progenies of transgenic insect-resistant maize, the inbred lines not only obtained the insect resistance but also improved the yield and quality, those also provide new germplasm resources for transgenic insect resistant maize breeding.