干旱驯化后节水抗旱稻苗期不同发育时间DNA甲基化模式变化分析

以一个节水抗旱稻沪旱3号为研究材料,经过连续6代干旱胁迫驯化后,采用甲基化敏感扩增多态性方法在苗期不同发育时间对原始代(G0)和第6代(G6)DNA甲基化变化情况进行分析。结果表明,沪旱3号甲基化位点比例约为34%,其中,全甲基化位点约占84%,半甲基化位点约占16%。在苗期,随着沪旱3号生长发育,甲基化水平下降。不同世代或/和不同发育时间差异甲基化位点占总检测位点的4.0%,其中,大部分仅与发育相关(57.9%),而世代之间无差异。干旱驯化后,G6的DNA甲基化模式发生了改变。G6与G0相比,在3叶期,去甲基化事件占主要部分(59.1%);在4叶期,甲基化事件占主要部分(47.9%)。生长发育涉及全基因组DNA甲基化变化,变化位点主要分布在启动子区域和外显子区域。功能聚类分析表明差异甲基化位点相关基因涉及广泛的功能。

Changes in DNA Methylation Pattern in a Water saving and Drought resistance Rice Variety at Three leaf and Four leaf stages after Drought Domestication

A water saving and drought resistance  rice Huhan 3 was grown under drought stress for  six successive generations after transplanting in the field. The variations in DNA methylation pattern between the original generation (G0) and the sixth generation (G6) were analyzed by methylation sensitive amplification polymorphism (MSAP) method. The results revealed that the methylated loci accounted for about 34% of the total. Among these, about 84% were full methylated loci and about 16% were hemi methylated ones. The DNA methylation level decreased from the three leaf stage to the four leaf stage in Huhan 3. Differentially methylated loci (DML) between generations or/and between different developmental stages accounted for 4.0% of the total, most of which were only related to plant development(579%). Compared to G0, the DNA methylation pattern of G6 changed after drought domestication, at three leaf stage,  de methylated events occupying 59.1%, while at four leaf stage, re methylated events occupied 47.9%. Genome wide alternations of DNA methylation were observed  along with rice growth and development, and DML mainly occurred on the gene′s promoter and exon region. The genes with DML were involved in a wide range of functions and participated in many important biological processes.