Analysis Of Vernalization Process Effect On DNA Methylation And Protein Level In Brassica Napus L

Only through low temperature processing (4℃,2-8weeks) during the seed germination or early vegetative growth period that most annual or biennial plants would bloom as canola and wheat. The low-temperature processing known as vernalization is a necessary developmental stage in the flowering development of cold-required plants. This physiological process of nucleic acid and protein change is under genetic control in which initially focused on protein level have drawn attention of researchers.Vernalization is essential for regulating plants from vegetative growth to reproductive growth. In China,90%of the Brassica napus are cold-required, they need to undergo the low temperature processing so as to flowering and fruiting.Existing research results show that DNA demethylation has played an important role in plant vernalization, changing both the type and quantity of protein in plant during the process. The research on DNA methylation and plant gene expression and regulation of the relationship is currently most focused on the model plant Arabidopsis. wheat, cabbage and other plant have also been reported in recent years.In this study, B. napus L Jinyu oil No.l used as experimental materials. Early spring B. napus L was sowed in different stages on the experimental fields to simulate the time of the low-temperature vernalization on rapeseed plant. Used flowering for the plant budding switched to reproductive growth and by vernalization standard to survey the ratio of plant vernalization. Detected the extent of genome-wide methylation by the methylation-sensitive amplified fragment polymorphism. Excel2010software was uesd to analysis the effects of the various periods by vernalization on plant genomic DNA methylation levels and patterns. B. napus L leaves with or without alabastrums were sampled to make the protein profiles by two-dimensional electrophoresis, then analysed the differences based on the protein profiles by PD Quest software.The main results are reported as follows:(1) Different sowing of B. napus L whose length of vernalization time were different, along with the extension of the sowing dates, followed by performance for all alabastrums, partial alabastrums, without alabastrums, plant genomic DNA methylation levels had been reduced, but the levels of DNA methylation reduced were different. The lower plant genome DNA methylation level, the higher the ratio of the plant by vernalization. In the same sowing period, the genome DNA methylation levels of plants passed the vernalization (12.50%) were higher than plants did not pass the vernalization(13.38%). Different sowing dates make Brassica napus L DNA methylation level of significantly different, the level of DNA methylation by vernalization were lower than without vernalization. The changed level of DNA methylation affected on the gene expression.(2) through protein profile analysis using the PD Quest software, there were161protein dots in the sample with alabastrum whereas155protein dots in the sample without alabastrum; through1.5times of significant difference analysis in the sample with alabastrum, there were52significantly up-regulated protein dots whereas36down-regulated protein dots.14Expressed protein dots in the sample with alabastrum whereas8expressed protein dots in the sample without alabastrum. In the same period, plants had more protein dots after vernalization than plants without being vernalized, which indicated that the number of protein dots increased after vernalization.