铁皮石斛同源四倍体与二倍体基因组及甲基化差异分析

Analysis of Genetic Variation and DNA Methylation Alteration in Autotetraploid and Diploid Dendrobium officinale

采用扩增片段长度多态性(AFLP)和甲基化敏感扩增多态性(MSAP)技术,探讨铁皮石斛二倍体经染色体加倍后得到四倍体的过程中,遗传差异和基因组DNA甲基化水平及模式变化情况,分析了铁皮石斛二倍体与同源四倍体的基因组变异及甲基化差异。AFLP结果显示,在25对引物组合扩增的1006条带中,474条为多态性带,多态率为47.12%;在甲基化水平上,二倍体铁皮石斛总甲基化率为92.64%,全甲基化率为62.06%,半甲基化率为30.58%,同源四倍体对应的甲基化率分别为88.68%、64.50%、24.17%。甲基化模式分析显示,铁皮石斛同源四倍体有28.63%的位点发生了去甲基化,30.63%的位点发生了过甲基化。铁皮石斛同源四倍体DNA碱基序列发生改变,总甲基率低于其二倍体,且其甲基化模式发生了较大调整。本研究为进一步探索四倍体铁皮石斛的表观遗传调控机制与基因组变异机理奠定了基础。

The objective of the study is to research the changes of genetic diversity,genomic DNA Methylation level and pattern after Dendrobium officinale diploid chromosome doubling,and to analysis of genomic mutation and methylation differences between diploid and tetraploid of Dendrobium officinale by AFLP and MSAP technique. AFLP results showed that,in amplified 1 006 bands with 25 pairs of primer combinations,474 bands showed polymorphism,the polymorphic rate was 47. 12%. In the level of methylation,the total methylation rate,full methylation rate and hemi- methylation rate were 92. 64%,62. 06% and 30. 58%,respectively for diploid Dendrobium officinale,88. 68%,64. 50% and 24.17% for autotetraploid Dendrobium officinale. The pattern of the methylation showed that about 28. 63% sites was demethylation in autotetraploid Dendrobium officinale,30. 63% sites has been methylated. Dendrobium officinale autotetraploid DNA sequence were changed,the total methylation rate were lower than the diploid and the methylation patterns changed significantly. This study laid a foundation for the further exploration of tetraploid Dendrobium officinale epigenetic mechanism and genetic mechanism.