橡胶树体细胞胚发生过程中DNA甲基化分析

DNA Methylation Changes during Somatic Embryogenesis of Hevea brasiliensis

摘要:

为了探讨巴西橡胶树（Hevea brasiliensis Muell. Arg.）自根幼态无性系与供体之间差异产生的原因，应用甲基化敏感扩增多态性扩增技术，对巴西橡胶树体细胞胚发生过程中基因组DNA胞嘧啶甲基化程度和模式进行了分析。结果表明，在巴西橡胶树体细胞胚发生过程中不同阶段材料中DNA 甲基化程度不同，其中花药中DNA 甲基化程度最高，体细胞胚中DNA甲基化水平最低；在体细胞胚发生过程中出现了I、Ⅱ和Ⅲ 3种类型的甲基化多态性带型的改变，包括它们的出现与消失。由此可见橡胶树体细胞胚发生过程中 DNA 的甲基化变化是一个复杂的过程，可能通过甲基化和去甲基化的方式调控基因的表达。

Abstract:

In order to understand the mechanism underlying the difference between self-rooting juvenile clone and donor clones, the extent and pattern of cytosine methylation in genomic DNA of Hevea brasiliensis were assessed by using the approach of methylation-sensitive amplification polymorphism（MSAP）. The results showed that notable changes in MSAP profiles of genomic DNA obtained from tissues during somatic embryogenesis. .The level of genomic DNA methylation in anther is the highest in all tissues, while the level of genomic DNA methylation in somatic embryo is the lowest in all tissues. Changes in types of MSAP bands among different tissues were frequently observed, including appearance and disappearance of type I, II, and III MSAP bands.. These results clearly demonstrate the complexity of DNA methylation change during somatic embryogenesis. DNA hypomethylation going with somatic embryogenesis appears to be a necessary step toward transcriptional activation in gene expression.