干旱胁迫下甘蓝型油菜全基因组DNA甲基化分析

为实现油菜抗旱稳产，了解甘蓝型油菜DNA甲基化及其在干旱胁迫应答过程中可能起到的作用，分别以 抗旱和干旱敏感油菜品系为材料，利用扩增片段单核苷酸多态性和甲基化检测技术（AFSM）对其在干旱和复水处 理下的叶和根组织进行全基因组DNA甲基化分析。结果发现：两个材料在三个处理条件下共鉴定到22 157个甲基 化位点，以5mCCGG全甲基化位点为主，主要发生在基因的编码区，其次是启动子区。干旱胁迫诱导油菜全基因组 DNA甲基化水平的变化，不同材料组织之间存在差异。干旱胁迫诱导叶组织整体甲基化水平升高，根组织差异不 明显；复水处理导致叶组织整体甲基化水平下降，根组织的甲基化水平在两个材料间存在差异。差异甲基化位点 的基因主要参与光合作用，类囊体、核糖体、质体和核膜等细胞组成，转运及转运蛋白活性等分子生物学功能。

Genome-wide analysis of DNA methylation under drought in rapeseed (Brassica napus L.)

To achieve consistent high yield of rapeseed, DNA methylation level of Brassica napus under drought stress was studied by a couple of drought-resistant (T78) and drought-sensitive (T88) rapeseed lines. Their whole genome DNA methylation in both leaves and roots under drought and recovery was investigated by AFSM (am? plified-fragment single nucleotide polymorphism and methylation) sequencing technology. Results showed that a to? tal of 22 157 methylation sites (mainly represented by 5mCCGG) were identified and mainly located in the coding re? gion of genes followed by promoter regions. Drought stress induced change of DNA methylation level in the whole genome. The levels were different between 2 lines, and among different tissues. Under drought stress, the methyla? tion level increased significantly in leaves, but not obvious in roots. In contrast, rehydration treatment significantly decreased the genome-wide methylation level in leaves, and caused divergent methylation level in roots between 2 lines. Those genes with differentially methylated sites were mainly involved in photosynthesis, cell composition in? cluding thylakoid, ribosome, plastid and nuclear membrane, and transport and transporter activity.