马哈利樱桃矮化砧的DNA甲基化水平及模式分析

该研究利用MSAP技术,对25株矮化马哈利樱桃和25株半矮化马哈利樱桃进行甲基化水平和模式分析,以探讨其矮化的表观性状与其基因组甲基化修饰的关系。结果表明:(1)从64对引物中筛选出15对引物,在半矮化组中共扩增4 577个条带,其中半甲基化336个,全甲基化1 274个;在矮化组中共扩增4 444个条带,其中半甲基化349个,全甲基化1 383个;t检验和方差分析表明,矮化组与半矮化组在总甲基化水平和全甲基化水平上差异极显著,在半甲基化水平上差异显著,矮化组甲基化水平高于半矮化组。(2)半矮化组单态性位点23个,多态性位点136个;矮化组单态性位点17个,多态性位点142个,表明矮化组多态性高于半矮化组。(3)多态性类型分析表明,矮化组出现A4类型的频率较半矮化组高,A2类型的频率较半矮化组低,即矮化组中发生超甲基化的位点多于半矮化组,且‘马哈利’基因组甲基化多态性位点主要发生在双链内侧甲基化位点以及超甲基化位点上。研究认为,马哈利樱桃矮化和半矮化的基因组甲基化水平及模式存在差异,马哈利砧木的矮化性状与其基因组甲基化修饰有关。

Analysis of DNA Methylation Levels and Patterns in Dwarf Rootstock of Prunus mahaleb

We analyzed the levels and patterns of DNA methylation in 25 dwarf rootstocks and 25 semi dwarf rootstocks of Prunus mahaleb by methylation sensitive amplification polymorphism marker(MSAP), in order to explore the correlation between dwarf characteristic and genome methylation modification. The results showed that: (1) 15 pairs were selected from 64 pairs of the MSAP primers. Methylation loci of 25 semi dwarf rootstocks of P. mahaleb were 4 577, hemi methylation loci were 336, and full methylation loci were 1 274. The total methylation loci of 25 dwarf rootstocks of P. mahaleb were 4 444, hemi methylation loci were 349, and full methylation loci were 1 383. T test and one way ANOVA showed that the level of full methylation and total methylation in semi dwarf group were extremely significantly different than that in dwarf group, and the level of hemi methylation was significantly different between the two groups. Meanwhile, the level of methylation in dwarf group was higher than that in semi dwarf group.(2) The singleton loci were 23 and polymorphic loci were 136 in semi dwarf group. The singleton loci were 17 and polymorphic loci were 142 in dwarf group. So it was concluded that the methylation polymorphism in dwarf group was higher than that in semi dwarf group.(3) Further analysis of the types of polymorphism showed that the frequency of A4 type was higher in dwarf group than that in semi dwarf group, and the frequency of A2 type was lower in dwarf group than that in semi dwarf group, indicating that the locus of hypermethylation in dwarf group was higher than that in semi dwarf group. The research indicated the correlation between dwarf characteristic of P. mahaleb and genome methylation modification from the differences in DNA methylation levels and patterns between dwarf group and semi dwarf group. The results might provide theoretical support for further breeding of cherry dwarf rootstock.