栽培稻×药用野生稻种间杂种基因组DNA甲基化的遗传与变异研究

摘要

为了探索栽培稻与药用野生稻种间杂种体内异源基因组重组引起的DNA甲基化变异规律,及其生物学效应,利用甲基化敏感扩增多态性(MSAP)技术对辽粳944、药用野生稻及其杂种F1不同发育时期的叶片和小穗基因组DNA甲基化水平和模式的遗传变异特点进行了分析.结果表明,辽粳944、药用野生稻及其杂种F1的叶片和小穗DNA的甲基化水平表现出相同的变化趋势,即随着生长发育的进行,DNA甲基化水平呈下降趋势,各组织的全甲基化率均显著高于半甲基化率(P=0.000);杂种在分蘖期、减数分裂期及开花期叶片DNA平均总甲基化率、全甲基化率和半甲基化率分别为20.19%,16.06%及4.13%,其甲基化水平高于双亲;而杂种在减数分裂期、小孢子发育期及花粉成熟期小穗DNA平均总甲基化率、全甲基化率和半甲基化率分别为17.38%,13.67%及3.71%,均比辽粳944高,而比药用野生稻低;杂种小穗的半甲基化率显著高于辽粳944(P=0.015).杂种叶片和小穗DNA的甲基化模式均有5种类型.经过对94个甲基化特异片段的序列分析,有38个片段的序列与已知或假定功能的基因具有同源性.为进一步研究栽培稻与野生稻种间杂种不育机理奠定了基础.%Aiming to analysis the characteristics of DNA methylation during the development processes of leaf and spikelet to explore the effect of genome shock in different tissues of hybrid F1 between O.sativa and O.officinalis,moreover,the possibility of biological effects,in this study,using the methylation sensitive amplified polymorphism technology (MSAP),patterns and levels of global genomic DNA methylation in leaf and spikelet from parents to interspecific hybrid F1 were investigated.The results showed that,the similar change trends of DNA methylation level in tissues of leaf and spikelet were observed in all the experimental materials,that is,along with the plant growth and development the DNA methylation level was on a downward trend,and the full methylation level was significantly higher than hemi-methylation level in both leaf and spikelet(P=0.000).In hybrid leaf tissue at the tillering stage, meiosis stage of pollen mother cells and flowering stage,the average total methylation level,full methylation level and hemi-methylation level was 20.19%,16.06% and 4.13%,respectively,which was higher than that of the two parents;while in hybrid spikelet tissue at the meiosis stage of pollen mother cells, microspore development stage and matured pollen grain stage,the average level of total,full and hemi-methylation was 17.38%,13.67% and 3.71%,respectively,which was higher than that of Liaojing 944 and lower than O.officinalis.However,only hemi-methylation level of hybrid was significantly higher than Liaojing 944(P=0.015).DNA methylation patterns in leaf and spikelet were very similar in parents and hybrid.Sequence analysis of 94 differentially methylated fragments showed that 38 fragments were sequence similarity in the NCBI database.The results would be helpful for further analysis of hybrid sterility between O.sativa and O.officinalis.