Polish Academy of Sciences, Institute of Dendrology, Kórnik, Poland.
PLoS One. 2013 Aug 5;8(8):e70693. doi: 10.1371/journal.pone.0070693. Print 2013.
The effects of storage and deep desiccation on structural changes of DNA in orthodox seeds are poorly characterized. In this study we analyzed the 5-methylcytosine (m(5)C) global content of DNA isolated from seeds of common pear (Pyrus communis L.) that had been subjected to extreme desiccation, and the seedlings derived from these seeds. Germination and seedling emergence tests were applied to determine seed viability after their desiccation. In parallel, analysis of the global content of m(5)C in dried seeds and DNA of seedlings obtained from such seeds was performed with a 2D TLC method. Desiccation of fresh seeds to 5.3% moisture content (mc) resulted in a slight reduction of DNA methylation, whereas severe desiccation down to 2-3% mc increased DNA methylation. Strong desiccation of seeds resulted in the subsequent generation of seedlings of shorter height. A 1-year period of seed storage induced a significant increase in the level of DNA methylation in seeds. It is possible that alterations in the m(5)C content of DNA in strongly desiccated pear seeds reflect a reaction of desiccation-tolerant (orthodox) seeds to severe desiccation. Epigenetic changes were observed not only in severely desiccated seeds but also in 3-month old seedlings obtained from these seeds. With regard to seed storage practices, epigenetic assessment could be used by gene banks for early detection of structural changes in the DNA of stored seeds.
储存和深度干燥对正种子中 DNA 结构变化的影响还没有很好的描述。在本研究中，我们分析了经历极度干燥的普通梨（Pyrus communis L.）种子以及这些种子产生的幼苗的 DNA 中 5-甲基胞嘧啶（m(5)C）的总体含量。通过发芽和幼苗出土试验来确定种子干燥后的活力。同时，使用 2D TLC 方法平行分析了干燥种子和从这些种子获得的幼苗的 m(5)C 总体含量。将新鲜种子干燥至 5.3%的含水量（mc）会导致 DNA 甲基化略有减少，而干燥至 2-3%mc 则会增加 DNA 甲基化。种子的强烈干燥会导致随后生成的幼苗高度变矮。种子储存 1 年后，种子中的 DNA 甲基化水平显著增加。强烈干燥的梨种子中 DNA 中 m(5)C 含量的变化可能反映了耐干燥（正）种子对强烈干燥的反应。不仅在严重干燥的种子中观察到表观遗传变化，而且在从这些种子中获得的 3 个月大的幼苗中也观察到了这种变化。就种子储存实践而言，表观遗传评估可被基因库用于早期检测储存种子中 DNA 的结构变化。
