DNA Methylation-Sensitive Amplification Polymorphism In Interspecific Hybrids Between Wheat And Rye

With the serious environmental problem arouse by the public, Wheat,the most important economical crops in the world and China, the yield and quality of wheat is increasingly demanding. Due to the usage of modern agricultural production technology, resulting in wheat germplasm resources is single, genetic diversity has been decreased at present. And it is urgent demeand on importing the exogenous germplasm from relative species, broadening the limited genetic background and enriching the genetic diversity. The rye,with the feature of the potential on quality gene source, is an important germplasm resources of wheat genetic improvement.And it is an necessary material for importing the quality gene from rye through heterochromatin system. It is theoretical and practical value to research these materials. DNA methylation is an important epigenetic modification, and plays an important role in regulation on regulating gene expression, cell differentiation, genomic imprinting and phylogeny, and that could be passed on to offspring through cell division, while it has become one of the popular research on the epigentics. Several studies have shown that the transform of rye chromosome can cause changes of levels and patterns of DNA methylation in wheat receptor, but the changes of genome DNA methylation modification after the transform of rye chromosome has not been reported.In order to probe into the relevance on genomic DNA methylation and inheritance of generations after the import of exogenous rye chromatin,and the relationship between powdery mildew resistance traits of sister lines and DNA methylation, and provide a theoretical basis for the genetic improvement of wheat in-depth applications, this study was based on the material of My15, Rw,903-6(BC2F8),903-6(BC2F9),903-6(BC2F10), 903-6-1,903-6-2, compare with parents, with analysis on DNA Methylation-Sensitive Amplification Polymorphism. The research result are as follows:1、To observe on the tested materials of meiotic, it states clearly that via more than eight consecutive backcrossing and selfing generations after import of rye chromosome, the material has stabilized.2、Through the technology MSAP test material amplified polymorphic DNA methylation analysis, there is a singinficant transform of genomic methylation levels after import of rye chromatin, total methylation level hybrids significantly higher than their parents, with an average of 86.16%, while wheat MY15 and rye were 71.53% and 78.77%, of which the half methylation levels of offspring were higher than their parents, with an average of 33.63%, while the permethylated levels of descendants are lower than their parents, with an average of 52.00%, which indicated that receptor through changes in methylation levels to adapt the quality of the parent nuclear fusion impact after the import of rye.3. Importing rye chromatin to wheat background would lead to changes in type of genomic methylation,and the highest type of hypermethylation, with the proportion of 20.87%-33.43%. Meanwhile, the lowest type of half methylation,with the proportion of 7.27%-11.71%, which indicated that the main ways of regulating gene expression is hypermethylation modification after the import of exogenous germplasm.4. With analysis on levels and types of methylation between three different generations of 903-6, found that as selfing increments, difference on level and type of methylation between different generations is not obvious, which indicated that import of rye chromatin into wheat produced changes in DNA methylation modification can better genetic stability.5. DNA methylation sensitive amplified polymorphism (MSAP) analysis of the two sister lines which against powdery mildew trait differences showed that there is slightly difference of the total methylation level between 903-6-1 (resistance to powdery mildew, IT= 0) and 903-6-2 (powdery mildew sensitive (necrotic spots), IT= 0;), respectively, 86.27% and 84.40%; types of methylation are identical, however, there has been some difference in ratio of methylation type, the hypermethylation ratio of 903-6-1 was 33.43%, higher than the powdery mildew-sensitive plants 903-6-2 (28.83%); While demethylation and hypomethylation ratio was 29.82%,less than that of 903-6-2 (33.25%), To sum up, the results indicated that changes of hypermethylation and demethylation patterns have different impact on phenotype of different disease resistance respectively.