木薯及其同源四倍体基因组与DNA甲基化差异分析

为研究染色体加倍对木薯基因组的影响,以及多倍化与2种不同倍性木薯之间DNA碱基序列的变化的联系。本研究以木薯品种"新选048"二倍体及其同源四倍体为研究材料,使用微卫星(simple sequence repeat,SSR)、目标起始密码子多态性(stand codon targeted polymorphism,SCo T)和甲基化敏感扩增多态性(methylation sensitive amplification polymorphism,MSAP)技术分别对木薯倍性间的遗传差异、DNA甲基化水平和模式进行分析。结果表明:利用SCo T和SSR均未检测出多态性条带产生,利用MSAP技术可检测出在DNA甲基化水平和模式均发生较大改变。二倍体和同源四倍体的总甲基化率分别为60.21%、59.52%,全甲基化率分别为39.92%、41.42%,半甲基化率分别为20.29%、18.10%。木薯多倍化后,其中有27.30%的位点发生了过甲基化,四倍体有25.00%的位点表现出去甲基化。本研究结果为探究木薯倍性间遗传差异和表观遗传变化规律进行了前期探索。 

Analysis of Genetic Variation and DNA Methylation Diversity in Diploid and Autotetraploid of Cassava

To study the effect of chromosome doubling in cassava genome and, explore the relationship between changes of DNA sequence in two different ploidy levels and polyploidization variation in cassava, the cassava variety ‘Xinxuan 048’ and its autotetraploid were taken as the materials to analyze the genomic mutation and DNA methylation diversity using microsatellite (Simple Sequence Repeat, SSR) and Stand codon targeted polymorphism (SCoT) molecular marker and Methylation Sensitive Amplification Polymorphism (MSAP) technique. The results showed that no polymorphic band occurred using SCoT and SSR molecular marker. In the level of DNA methylation，both of the level and pattern of the autotetraploid cassava changed. The total methylation rate of the diploid and the autotetraploid was 60.21% and 59.52%, respectively；the full methylation rate was 39.92% and 41.42%, respectively；the hemi methylation rate was 20.29% and 18.10%, respectively. In comparison to the diploid, the pattern of the methylation showed that about 25.00% sites was demethylation, 30.63% sites has been methylated in autotetraploid cassava. This research is a foundation for the further exploration of genetic differences and epigenetic regulation after cassava polyploidization.