| High molecular weight (HMW) glutenin subunits are one group of the major components of storage proteins in wheat seeds. Variation in the amount and composition of HMW glutenin subunit would affect the flour processing quality. 1Dx5 and 1Ax1 subunits have high quality scores and are known as subunits with good bread-making quality. It's significant for improving the quality of Chinese wheat to transfer the genes expressing these two subunits into elite wheat varieties and it's an important way of improving the wheat bread-making quality in China. In this study, three crosses between transgenic wheat lines B72-8-11b, B102-1-2 and Chinese elite wheat varieties Chuan89-107, Emai18 were carried out: Chuan89-107×B72-8-11b, Chuan89-107×B102-1-2 and Emai18×B72-8-11b. SDS-PAGE, PCR and Southern-blot were used to study the inheritance and expression of two kinds of multi copies of foreign genes, and single plant and plant series with good characters were screened artificially in the cross progenies. There were many theoretical and practical value. The results were listed at the following part.1. F1 seeds of three cross combinations were analyzed by SDS-PAGE and DNA were extracted from leaves of F1 for PCR. The results showed that the crosses were valid and the materials of F1 could be used for the following researches.2. F2, BC1F2, BC1F3, BC2F1, BC2F2 and BC2F3 progenies of 89-107×B72-8-11b,Emai18×B72-8-11b were obtained. SDS-PAGE analysis showed that 5-10 copies of 1Dx5 genes were inserted at one locus and they expressed according to the Mendelian law. Expression analysis of F2, BC1F2 and BC1F3 progenies of Chuan89-107×B102-1-2 were carried out by SDS-PAGE. The results substantiated the conclusion of two insertion loci of 1Ax1 genes and it also showed that the expression of multi copies of 1Ax1 gene obey to the Mendelian law.3. Insertion of the multi copies of 1Dx5 gene led to the variation of HMW-GS. These 1Dx5 genes over-expressed in transgenic wheat B72-8-11b stably and they expressed in different levels in cross and back-cross progenies. On the other hand, a new subunit whose molecular weight was near to 1Ax1 was produced in some progenies. Insertion of multi copies of 1Ax1 didn't affect the HMW-GS of wheat.4. PCR and Southern-blot analysis of BC1F3, BC2F3cross progenies showed that foreign genes were still inserted in the genome and copies of 1Dx5 was higher than that of 1Ax1.5. Transgenic wheat lines B7-8-11b and B102-1-2 were obtained through the same method, but their foreign genes had different integration, inheritance and expression mechanisms in the same genotype.6. Many single plants and plant series with application value were screened. The plant series in which the 1Dx5 gene can be over-expressed are very important for improving the bread-making quality; the series whose HMW-GS is different in foreign gene can be good materials for analysis of the subunits's function and in the course of screen, we get many materias whose HME-GS are different. They are the new materials in wheat for research and application. There are some other materials in which the report gene can not express can accelerate the course of application of new plants in biosafty.The results of this study provided a new idea of wheat breeding, and further breeding of these plant series can produce some new wheat lines. |
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