Study On The Impact Of The Male Sterile Cytoplasm To The Major Agronomic Trait And The Genome DNA Methylation In Rice

Since the wild type materials with pollen abortion found and then the cytoplasmnucleus interactions of male steril came out,the realization of hybrid rice,and it is widely used in production,which bring huge economic benefits.How about the same cytoplasm influencethe different properties,is there some similarities and difference in cytoplasmic effects from different sources and different types,and how to make rational use of the diversity of sources of cytoplasmic male sterility,which are hybrid rice breeding and production of new issues facing.DNA methylation,which consist in much propagation,is an significant epigenetic modification.It plays an important role in gene expression and regulation,plant cell differentiation,genomic imprinting and phylogeny.According to many researches,the variation of DNA methylation can be transferred to the offspring by cell division.To date,the research methods on DNA methylation can be classified into three types:genome-wide methylation analysis,gene-specific methylation analysis and newly methylated sites screening.The technique of methylation-sensitive amplified polymorphism(MSAP) can be used for DNA methylation analysis of 5'-CpCpGpG site.In this study,using four male sterile lines such as D types and their corresponding maintainer lines to hybrid with the same restorer line respectively,and study on the effect of cytoplasmic to plant height,effective panicle,panicle length,seed setting rate,grain weight,photosynthetic rate and yield in hybrid,using MSAP technology to analysis the parents of four combinations(male sterile lines and the corresponding maintainer lines) and its corresponding hybrid F₁,It can help us understanding the cytoplasmic effects.The main results were as follows:1.Due to the maintainer lines and the corresponding nuclear male sterile lines with the characteristics of heterogeneity,through the hybrid F₁ of the maintainer lines and the restoring lines compared to the hybrid F₁ of the male sterile lines and the same restoring lines in the biological traits,it found that the hybrid F₁ of the maintainer lines and the restoring lines dominate in the panicle length,no of productive,1000 -grain weight,seed -rate,photosynthetic rate,yield,but the plant length instead.2.By analysis the maintainer lines and the male sterile lines of the level of methylation which having the same nuclear heterogeneity,we found that the average MSAP ratio(the ratio of total methylated sites to total detected sites)of the maintainer lines of each combination droped by 1.13%～3.35%compared to the corresponding male sterile lines of each combination,among of them Gang46B droped by 3.35%maximum and theJin23B droped 1.13%minimum.3.Through analysis the MSAP ratio of hybrid F₁:We found that compared to the average MSAP ratio(the ratio of total methylated sites to total detected sites )of the F_1B and F_1A,F_2B and F_2A,F_3B andF_3A,F_4B and F_4A,it drop by 0.71%,0.31%,2.39%,0.39% respectively,the ratio of full methylation(double strands CmCGG) drop by1.05%,0.34%,1.05%,0.88%respectively,Among of them,the F_3B Fell by 2.39%,1.05%maximum Compared to F_3A.4.Compared to the hybrid F₁ and their parent,there would be five mehtylation mutation patterns:Type A,same methylation pattern between hybrid and their parent;Type B, demethylation;Type C,hypermethylation;Type D,hypomethylation;Type E,uncertain type.5.In the course of the formation of hybrids,the degree of the methylation depressed of the hybrid F₁ which produced by maintainer lines and R527 slightly higher than the hybrid F₁ of the corresponding male sterile lines and R527.on the other hangd,in the up or maintain of the methylation compared to the corresponding parent,the hybrid F₁ of maintainer lines and R527 is slightly lower than the hybrid F₁ of the corresponding male sterile lines and R527.