DNA甲基化对橡胶树老态和幼态无性系茎围差异的影响

Effects of DNA Methylation on the Difference of Stem Girth between Old Clones and Young Clones of Hevea brasiliensis

茎围是影响橡胶树胶乳产量的因素之一。橡胶树的幼态无性系和老态无性系,由同一棵树不同部位的芽嫁接获得,它们的DNA序列相同,但产胶量却存在差异。为明确橡胶树老态和幼态无性系茎围差异与基因组DNA甲基化差异的表观遗传关系,本研究先测量橡胶树老态和幼态无性系的茎围。然后利用MSAP技术分析橡胶树老态和幼态无性系的DNA甲基化差异。SAS分析结果显示:幼态无性系茎围为(39.40±3.14)cm,老态无性系茎围为(37.01±3.52)cm,差异达到显著水平;MSAP结果显示:橡胶树老态和幼态无性系DNA甲基化水平和DNA甲基化模式均有差异。幼态无性系的DNA甲基化水平为36.5%,高于老态无性系的27.2%。老态和幼态无性系中维持甲基化、重新甲基化和去甲基化模式都有发生。和老态无性系相比,幼态无性系发生模式变化最多的重新甲基化。对差异条带回收克隆比对后,检索到与拟南芥的抗旱性等基因同源性很高。这些差异可能是导致橡胶树老态和幼态无性系间茎围差异的原因之一。

The stem circumference of rubber trees affects the latex yield.Young clones and old clones of rubber trees,their DNA sequences will not change,because they are from same tree.But their latex yield will be different after adulthood.In order to ascertain the epigenetic relationship between the stem circumference and the DNA methylation of the old and young clones of rubber trees,the study measured their stem circumference,and analyzed the difference of DNA methylation.SAS analysis showed that the difference reached a significant level.The stem circumference of young clones was(39.40±3.14)cm,but the old clones was(37.01±3.52)cm.MSAP analysis showed that the old and young clones are differences both in DNA methylation levels and DNA methylation patterns.The DNA methylation level of young clones was higher than that of old clones.The DNA methylation level of young clones was 36.5%,but old clones was 27.2%.Both of the clones have maintenance methylation,remethylation,and demethylation patterns.Compared to old clones,young clones have the most frequent pattern changes in remethylation.The drought resistance genes were highly homologous to Arabidopsis thaliana by the retrieval one of different bands.Perhaps it is reasons for their DNA differentially expressed,and made differences in stem circumference between them.