Abstract: The objectives of this study were to analyze the cytosine methylation dynamics and gene expression of Lolium perenne during seed germination under 0 and 150 mmol·L^-1 NaCl treatments. Methylation sensitive amplified polymorphism (MSAP) method was used to analyze the level and variation patterns of DNA methylation at different times (0, 1, 2, 4, 6, 7 days). Eight NaCl stress related genes were selected for real-time quantitative PCR analysis. MSAP results showed that the level of global DNA methylation decreased during the whole germination process. The changes of DNA methylation were detected in both coding region and non-coding region of the genome. NaCl treatment increased the level of DNA hypermethylation and decreased the level of DNA hypomethylation. Metabolism was enhanced during seed germination. The relative expression of eight NaCl stress related genes had an increasing trend. Seed germination was seriously repressed under NaCl stress, and the expression levels of related genes were lower in NaCl treatment than control at most germination times.

Key words: Lolium perenne L., Seed germination, DNA methylation, NaCl, Gene expression

摘要： 为了解黑麦草（Lolium perenne）种子在正常条件与NaCl胁迫下萌发过程中DNA甲基化动态变化以及重要盐胁迫相关基因的表达。运用甲基化敏感扩增多态性技术分析对照和150 mmol·L^-1 NaCl处理下黑麦草种子萌发过程（0，1，2，4，7 d）的DNA甲基化水平及动态变化，并通过实时荧光定量 PCR（QRT-PCR）检测8个重要的盐胁迫相关基因的表达情况。结果表明：黑麦草种子萌发过程中甲基化水平呈下降趋势，以双链甲基化方式为主，甲基化变化同时发生在编码序列和非编码序列中。NaCl处理下DNA甲基化程度高于CK，而去甲基化程度低于CK，最终导致NaCl处理下基因组净的甲基化位点数目增加。黑麦草种子耐盐萌发过程中代谢增强，8个盐胁迫相关基因表达量呈上升趋势，而NaCl胁迫延缓了种子萌发进程，在大多数时间点的基因表达低于对照。

关键词: 黑麦草, 种子萌发, DNA甲基化, NaCl, 基因表达