Chwialkowska Karolina, Nowakowska Urszula, Mroziewicz Anna, Szarejko Iwona, Kwasniewski Miroslaw
Department of Genetics, University of Silesia in Katowice, Jagiellonska 28, 40-032 Katowice, Poland.
Department of Genetics, University of Silesia in Katowice, Jagiellonska 28, 40-032 Katowice, Poland
J Exp Bot. 2016 Feb;67(4):1109-21. doi: 10.1093/jxb/erv552. Epub 2016 Jan 5.
One of the strategies of plant adaptation to stress is the modulation of gene expression, which may result from the regulation of DNA methylation. This study attempted to characterize and compare the barley methylome of leaves and roots under water-deficiency treatment and in the subsequent rewatering phase. Our results, obtained using methylation-sensitive amplification polymorphism sequencing analysis, indicated that the overall DNA methylation level in the barley genome was high and in general stable under water-deficiency conditions. Nevertheless, numerous differentially methylated sites (DMSs) were induced by stress in the leaves and roots. Equal proportions of novel stress-induced methylation and demethylation events were observed within the genes in the leaves, but new methylations dominated in the roots. Repetitive elements preferentially underwent demethylation in the leaves and novel methylations in the roots. Importantly, rewatering and plant recovery resulted in the reversibility of the majority of stress-induced methylation events, but this process was more efficient in the leaves than in the roots. Different biological processes were enriched within the subsets of the DMSs that were identified in the genic regions of leaves and roots. We assume that the organ specificity of the methylome changes in response to water deficiency might be an important regulatory mechanism that leads to multi-level mechanisms of stress tolerance in barley.
植物适应胁迫的策略之一是基因表达的调控，这可能源于DNA甲基化的调节。本研究试图对水分亏缺处理及随后复水阶段大麦叶片和根的甲基化组进行表征和比较。我们使用甲基化敏感扩增多态性测序分析获得的结果表明，大麦基因组中的总体DNA甲基化水平较高，且在水分亏缺条件下总体稳定。然而，胁迫在叶片和根中诱导了大量差异甲基化位点（DMS）。在叶片的基因中，观察到新的胁迫诱导甲基化和去甲基化事件的比例相等，但在根中，新甲基化占主导。重复元件在叶片中优先发生去甲基化，而在根中发生新的甲基化。重要的是，复水和植物恢复导致大多数胁迫诱导的甲基化事件具有可逆性，但这一过程在叶片中比在根中更有效。在叶片和根的基因区域中鉴定出的DMS子集中，不同的生物学过程得到了富集。我们认为，甲基化组响应水分亏缺的器官特异性变化可能是导致大麦多层次胁迫耐受机制的重要调控机制。
