Construction Of High Efficient Rice Transformation System And Improvement Of Resistance To Disease And Non-biologic Stress

The methods used in rice transgenic manipulation have been improving , but there are still some problem existed, such as, low transgenic rate, low expression of exogcnc, random of integration site and gene silence. So in order to get ideal transgenic plants and construct a high efficient transformation system, a large group made up of transgenic plants should be got first.1 lowevcr, many research results indicated that genotype is a hinder of transformation, that is, some genotype can't be transformed successfully or easily. That's the main problem gets in the way. Thus, we came forth to use model varieties for transformation as media. Model varieties for transformation are which can induce calli easily and can be transformed much more easily than the others. Now, the breeding procedure can be altered. First, target exogene can be transformed into model varieties to construct 'exogene bank'. Then the exogenes can be transformed to many other varieties by hybrid and MAS(molecular marker assisted selection). Thus, the problem of genotype can be solved.Bacterial blight caused by Xanthomonas oryzae pv. oryzae is one of the most important diseases affecting rice products in many areas of the world. And non-biologic stress, such as salt stress, water stress and temperature stress also influences products of rice. To improve the resistance of hybrid rice, we transferred the gene Xa21, which has broad-spectrum resistance to bacterial blight, and salt-resistant gene CMO into the elite restorer and maintainer lines of r\ce((Oryzae saliva L.).Twenty-four varieties of different genotypes were studied in the experiment, and biolistic bormbardment and Agrobateriwn-mediated transformation were used. From the experiment, such results below were got. ? To construct a nice acceptor system. Young spike and embryo are ideal explants,which have higher calli inducing rate than seed(mature embryo). Furthermore the calli induced from them can be transformed more easily. Between them, young embryo is much better, because large amount young embryo can be got.? The calli inducing rate of the varieties' young embryo was mostly over 80%, and that of shuhui881,838R,shuhui527,jianghui151 is 100%. So it was not the main factor influenced the efficiency of transformation. HygB-resistant calli rate and differentiation rate mainly influenced the transformation efficiency, especially the latter did more. It was found in the test, some genotype can form a great deal of resistant calli, but most of the calli can't different, so only few transgenic plants could be got in result.? To construct a high efficient transformation system by model varieties. Evaluated all the factors, DXiangB(elite maintainer line of indica rice) and CDR22(elite restorer line of indica rice) are best varieties for transformation among all the genotypes tested. The calli inducing rate, hygB-resistant calli rate and differentiation rate of them are much higher than the others. And the transformation rate is distinctly higher than the others. That of D Xiang B is 29.15%(via Agrobaterium) and 28.40%( via biolistic bormbardmeni ). And that of CDR22 is 19.08%( via Agrobaleriwn) and 21.37%( via biolistic bormbardmenf).? Eighteen varieties were successfully transformed and transgenic plants of T2 and Ti were got? Transgenic plants with Xa21 of eighteen varieties were got. Identification in the field showed that most transgenic plants had better resistance to bacterial blight. The average length of disease spot was 3.0 to 5.0cm and percentage of disease spot was 9.0% to 12%. And those of contrast were 5.2 to 7.0cm and 20% to 30%.? Transgenic plants with DXiangB, Shuhui881 and CDR22 were got, and the identification in the field is carrying on.