土霉素胁迫下拟南芥基因组DNA甲基化的MSAP分析

以拟南芥 (Arabidopsis thaliana)为材料,研究不同土霉素浓度下拟南芥幼苗生长发育及基因组DNA的甲基化水平和变化模式。结果表明,3、5、7\,9 μmol/L土霉素胁迫对拟南芥幼苗的根长和株高有显著抑制作用;但对拟南芥幼苗的侧根数量有显著促进作用。甲基化敏感扩增多态性 (methylation-sensitive amplification polymorphism, MSAP)分析表明,经3、5、7\,9 μmol/L土霉素处理后基因组DNA甲基化比率分别为17.91%、12.50%、11.81%和14.62%,均低于对照 (18.18%)。结果表明,拟南芥经土霉素胁迫后存在基于 DNA甲基化水平和模式改变的表观遗传变异,5-甲基胞嘧啶百分含量的变化无统一趋势或规律。与对照相比,3、5、7\,9 μmol/L土霉素胁迫下拟南芥幼苗基因组DNA的甲基化和去甲基化分别为13.29%、9.22%、8.03%、12.59%和2.80%、4.26％、5.11%、4.90％。由此推测,DNA甲基化可能是植物适应土霉素胁迫机制的机制之一。

MSAP analysis of DNA methylation in Arabidopsis (Arabidopsis thaliana) under Oxytetracycline Stress

The objectives of this research were to assess the effect of oxytetracycline stress on the development as well as genomic DNA methylation levels and patterns of Arabidopsis thaliana seedlings. Oxytetracycline at concentrations of 3, 5, 7, and 9 mol/L 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 9 mol/L, methylation and demethylation of A. Thaliana seedling genomic DNA were respectively 13.29%, 9.22%, 8.03%, 12.59% and 2.80%, 4.26%, 5.11%, 4.90%. We suggest that DNA methylation might be one of the mechanisms used by plants to combat oxytetracycline stress.