王艺雯,李利红,仪慧兰.H2O2诱导拟南芥NIT2基因甲基化特征与转录水平改变[J].环境科学学报,2015,35(1):324-328
H2O2诱导拟南芥NIT2基因甲基化特征与转录水平改变
- DNA methylation alterations and gene transcription changes of NIT2 in Arabidopsis plants induced by hydrogen peroxide
- 基金项目：国家自然科学基金项目(No.30870454,30470318,31371868);高等学校博士学科点专项科研基金项目(No.20121401110007);山西省留学回国基金项目(No.2009022);中国博士后科学基金项目(No.2014M551056)
- 摘要：用外源H2O2处理拟南芥植株,亚硫酸氢盐修饰后测序法分析胁迫生理中NIT2基因启动子区甲基化特征变化,RT-PCR检测该基因的转录水平.结果显示:用100 ul·L-1的H2O2处理3 h后,NIT2启动子区胞嘧啶总甲基化水平与对照差异不大,但对照组CHG(H为C、A或T)和CG位点甲基化水平分别为35.0%和93.3%,H2O2处理组CHG和CG位点甲基化水平分别为50.0%和96.9%;H2O2处理组CHH位点则表现为甲基化水平升高、降低或去甲基化;H2O2胁迫组拟南芥地上组织中NIT2基因转录水平提高.研究结果表明:NIT2基因的转录应答和DNA甲基化修饰参与了植株的逆境生理过程;氧化胁迫与DNA甲基化改变、基因转录上调同时发生,说明胁迫诱发的活性氧增高可能参与胞嘧啶甲基化修饰和基因转录的调节.
- Abstract：DNA methylation is one of the most important heritable epigenetic modifications of the genome and could be changed in plant responses to environmental stresses. Environmental stimuli can induce DNA methylation alterations and some important consequences for plant adaptations. In this study, DNA methylation alterations and transcriptional changes of a gene encoding nitrilase 2(NIT2) protein in Arabidopsis were investigated under oxidative stress. Arabidopsis shoots, which were exposed to 100 u·L-1 H2O2 for 3 h and showed increased intracellular reactive oxygen species (ROS) levels, were selected as the materials. DNA methylation analysis by bisulfite sequencing showed that the total level of methylation in the promoter region of NIT2 gene did not change much after plants were exposed to 100 u·L-1 H2O2 for 3 h, but for the different DNA sequence contexts in the promoter region of Arabidopsis NIT2 gene, cytosine residues could have different methylaiton status in H2O2-exposed samples. In control plants, the methylation levels of CHG (where H is C, A or T) and CG contexts were 35.0% and 93.3% respectively, while in H2O2-exposed samples, the methylation levels of CHG and CG contexts were 50.0% and 96.9% respectively. For CHH context, cytosine residues could be hypomethylated, hypermethylated or demethylated in H2O2-exposed samples. Exposure to H2O2 also induced transcriptional activation of NIT2 gene in Arabidopsis shoots. The present results indicated that H2O2 caused the changes of transcription and DNA cytosine methylation of NIT2 gene, which can affect plant physiology contributing to plant adaptation. Our results also suggested that increased ROS may play a key role in triggering cytosine methylation and gene expression in plant responses to environmental stresses.
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