高温胁迫下水稻基因组DNA表观遗传变化MSAP分析

MSAP Analysis of Epigenetic Changes in Rice(Oryza sativa. L) under High-temperature Stress

目的:研究高温胁迫对水稻基因组DNA甲基化变化的影响,筛选出一批与高温胁迫的相关基因,研究DNA基因化与基因转录水平之间的关系。方法:在人工气候箱子中,对四叶期的水稻幼苗进行38度高温处理,分别取0 h、2 h、4 h、8 h、12 h、16 h和24 h七个不同时间点的幼叶提取DNA与RNA,利用MSAP技术检测总甲基化水平变化,RT-PCR检测相关基因的转录本的表达量变化。结果:与对照组0 h幼叶相比,高温处理下的2 h、4 h、8 h、12 h、16 h和24 h幼叶的总体甲基化水平依次是37.14%、36.79%、36.00%、35.50%、35.43%、34.64%和34.57%,可知幼叶DNA甲基化水平在高温处理后不断降低。此外,RT-PCR结果显示筛选的两个与甲基化相关的基因(PP2C和RAFP)的转录水平与甲基化水平呈负相关。结论:基因组甲基化作为一种重要的表观遗传调控方式,可以通过调控相关的基因的表达量水平来防御高温胁迫。

Objective： In order to research the effect of high temperature stress on rice genome DNA methylation changes, screen a number of related genes associated with high temperature stress and investigate the relationship between DNA methylation levels with those related genes transcription. Methods： In the artificial climate incubator, seedlings had been treated at 38 degree temperature at four-leaf stage. Those young leaves from seven samples, which were 0 hour point sample, 2 hours point sample, 4 hours point sample, 8hours point sample, 12 hours point sample, 16 hours point sample and 24 hours point sample, were collected from different time periods to extract DNA and RNA for MSAP and RT-PCR analyzing in overall methylation changes and the related gene transcription level.Results： Compared with the control group（0 hours point sample）, under the high temperature treatment, the methylation levels of the samples from 2 hours, 4 hours, 8 hours, 12 hours 16 hours and 24 hours were 36.79 %, 36.00 %, 35.50 %, 35.43 %, 34.64 % and 34.57 %,and methylation levels declined in the young leaves. In addition, the RT-PCR results show that the two selected methylation related genes＇ transcription（PP2C and RAFP） were negatively correlated to the level of methylation. Conclusions： Genomic methylation as an important epigenetic regulation method can be achieved by regulating the expression of related genes to fit the high temperature treatment.