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Effects Of Four Drugs On DNA Methylation Of Arabidopsis Thaliana

Posted on:2012-01-14Degree:MasterType:Thesis
Country:ChinaCandidate:Y Q DuFull Text:PDF
GTID:2120330332995207Subject:Genetics
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DNA methylation plays an important role in gene expression regulation during biological development and tissue differentiation in plants. The objectives of this research were to assess the effect of four durg (oxytetracycline, Dimethyl sulfoxide, mannitol, curcumin) treatment on the development as well as genomic DNA methylation levels and patterns of Arabidopsis thaliana seedlings.(1) The effect of oxytetracycline stress on the development as well as genomic DNA methylation levels and patterns of Arabidopsis thaliana seedlings was assessed. Oxytetracycline at concentrations of 3, 5, 7, and 9μmol·L-1 visibly inhibited root and stem enlongation of A. thaliana seedlings, but significantly promoted lateral root proliferation. Methylation sensitive amplified polymorphism (MSAP) analysis showed that genomic DNA methylation levels of oxytetracycline stressed seedlings were lower than that of the untreated plants. The results indicated that oxytetracycline stress induced epigenetic variations in A. thaliana seedlings; no clear trend or pattern of 5-methylcytosine percentage change emerged. At oxytetracycline concentrations of 3, 5, 7, and 9μmol·L-1, methylation and demethylation of A. Thaliana seedling genomic DNA were respectively13.29%, 9.22%, 8.03%, 12.59% and 2.80%, 4.26%, 5.11%, 4.90%.(2) The effect of DMSO stress on the development as well as genomic DNA methylation levels and patterns of Arabidopsis thaliana seedlings was assessed. DMSO at concentrations of 130, 260, 400, and 500μmol·L-1 visibly inhibited root and stem elongation of A. thaliana seedlings. Methylation sensitive amplified polymorphism (MSAP) analysis showed that genomic DNA methylation levels of 260-500μmol·L-1 DMSO stressed seedlings were lower than that of the untreated plants. The results indicated that DMSO-induced epigenetic variations in A. thaliana seedlings; At DMSO concentrations of 130, 260, 400, and 500μmol·L-1, methylation and demethylation of A. Thaliana seedling genomic DNA were respectively 7.21%, 6.03%, 11.62%, 10.2% and 6.25%, 10.05%, 8.08%, 8.67%.(3) The effect of mannitol treatment on the plant growth as well as genomic DNA methylation levels and patterns of Arabidopsis thaliana seedlings was assessed by methylation sensitive amplified polymorphism (MSAP) technique. The results showed that 50, 100, 150 and 200 mmol·L-1 mannitol obviously promoted plant root length of Arabidopsis seedlings. The analysis by MSAP showed that levels of 5-mdC in mannitol-treated seedlings were also altered significantly, ranging from 17.75%, 21.15%, 15.49% to 46.10% in plants treated with 50, 100, 150 and 200 mmol·L-1 mannitol, respectively. The results indicted that mannitol causes epigenetic variations in all the samples based on different levels and patterns of DNA methylation. With 50, 100, 150 and 200 mmol·L-1 mannitol treatment, methylation and demethylation of DNA were 5.78%, 15.48%, 10.71%, 33.73% and 10.98%, 5.36%, 8.33%, 7.69%. Mannitol causes a dose-dependent and transient change of global 5-methyldeoxycytidine levels in Arabidopsis seedlings.(4) DNA methylation plays an important role in gene expression regulation during biological development and tissue differentiation in plants. DNA demethylation agents have an important role in terms of plants methylation. The Curcumin, a potential demethylation inhibitor, was used to analyse its role in Arabidopsis thaliana. This study adopted methylation-sensitive amplified polymorphism (MSAP) to compare the levels of DNA cytosine methylation at CCGG sites in T0, T1 and T2 Arabidopsis lines treated with curcumin, respectively. We detected specific loci methylation patterns in cytosine methylation level and the changing tendency among the three lines. The methylation level of the T0 lines was the lowest than those in the T1 and T2 inbred lines. The full methylation of internal cytosine was the dominant type in the genome after the plants grown for 6 weeks without curcumin treatment.
Keywords/Search Tags:Arabidopsis thaliana, methylation, oxytetracycline, DMSO, mannitol, curcumin
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