The Progeny of <em>Arabidopsis thaliana</em> Plants Exposed to Salt Exhibit Changes in DNA Methylation, Histone Modifications and Gene Expression

Plants are able to acclimate to new growth conditions on a relatively short time-scale. Recently, we showed that the progeny of plants exposed to various abiotic stresses exhibited changes in genome stability, methylation patterns and stress tolerance. Here, we performed a more detailed analysis of methylation patterns in the progeny of Arabidopsis thaliana (Arabidopsis) plants exposed to 25 and 75 mM sodium chloride. We found that the majority of gene promoters exhibiting changes in methylation were hypermethylated, and this group was overrepresented by regulators of the chromatin structure. The analysis of DNA methylation at gene bodies showed that hypermethylation in the progeny of stressed plants was primarily due to changes in the 5′ and 3′ ends as well as in exons rather than introns. All but one hypermethylated gene tested had lower gene expression. The analysis of histone modifications in the promoters and coding sequences showed that hypermethylation and lower gene expression correlated with the enrichment of H3K9me2 and depletion of H3K9ac histones. Thus, our work demonstrated a high degree of correlation between changes in DNA methylation, histone modifications and gene expression in the progeny of salt-stressed plants.植物能够在相对较短的时间尺度内适应新的生长环境。近期，本团队的研究表明，暴露于多种非生物胁迫的植物其子代会出现基因组稳定性、甲基化模式以及胁迫耐受性的改变。本研究中，我们针对暴露于25 mM与75 mM氯化钠胁迫的拟南芥（Arabidopsis thaliana）子代的甲基化模式开展了更为细致的分析。我们发现，多数甲基化水平发生改变的基因启动子呈现高甲基化状态，且该类基因中染色质结构调控因子的占比显著偏高。对基因本体区域DNA甲基化的分析显示，胁迫处理植物子代中的高甲基化现象主要源于5′端、3′端以及外显子区域的甲基化改变，而非内含子区域。经检测的高甲基化基因中，除1个以外其余所有基因的表达水平均出现下调。对启动子及编码序列区域的组蛋白修饰分析显示，高甲基化与基因表达下调与组蛋白H3K9me2的富集以及H3K9ac的缺失呈现显著相关性。综上，本研究证实，盐胁迫植物子代中DNA甲基化改变、组蛋白修饰与基因表达三者之间存在高度相关性。