同源四倍体与二倍体水稻基因组及甲基化差异分析  

Analysis of Genetic Variation and DNA Methylation Alteration in Autotetraploid and Diploid Rice

作　　者：杨琼[1,2] 李辉[1] 左钦月[1] 邱琳[1] 陈丽[1] 罗科[1] 涂升斌[1] 

机构地区：[1]中国科学院成都生物研究所,成都610041 [2]中国科学院大学,北京100049

出　　处：《应用与环境生物学报》2013年第4期630-636,共7页Chinese Journal of Applied and Environmental Biology

基　　金：四川省产学研创新联盟合作项目(2012ZZ0004)资助~~

摘　　要：DNA甲基化在真核生物的生长发育过程中起着重要的调控作用.为了解水稻同源四倍体与二倍体之间的基因组及甲基化修饰差异,探究二倍体与同源四倍体的遗传差异和基因组DNA甲基化水平及模式变化,以冈46B、明恢63、绵恢725、成恢149、海天、什香6个二倍体水稻及相应的6个同源四倍体水稻为材料,采用微卫星分子标记技术(SSR)及甲基化敏感扩增多态性(Methylation-sensitive amplification polymorphism,MSAP)分析等方法进行研究.SSR结果显示,所试同源四倍体水稻的基因组与二倍体水稻基因组大部分相同,采用的引物中有3对引物多态性较好,在不同倍性水稻间扩增出特异性条带.经不同倍性甲基化水平分析,同源四倍体材料的平均总甲基化率(24.0%)明显低于二倍体材料的平均总甲基化率(28.15%).两个倍性材料间的全甲基化与半甲基化差异也较大:二倍体材料的全甲基化率平均为6.24%,半甲基化率平均为22.03%;同源四倍体水稻材料全甲基化率平均为7.44%,半甲基化率平均为16.61%.甲基化程度并未因多倍化而增加,这说明同一品种水稻的二倍体与同源四倍体间的DNA发生了甲基化修饰变化.进一步对不同倍性水稻DNA甲基化模式的变化特征进行分析,结果显示同源四倍体水稻中平均约有11.6%发生了去甲基化,平均约有24.11%位点发生了过甲基化,过甲基化基因的比例显著高于去甲基化的比例.研究表明同源四倍体水稻可能通过对一些功能基因的甲基化不表达,以缓和基因组加倍剂量效应造成的影响.DNA methylation plays an important role in regulating the process of growth and development in eukaryotes. The purpose is to investigate the genome and methylation differences between diploid and tetraploid, explore the genetic differences and genomic DNA methylation level and pattern changes. The diploid and autotetraploid rices Gang 46B, Minghui63, R725, Chenghui149, Haitian and Shixiang were analyzed by SSR and MSAP technique. The results showed that most genomes of the autotetraploid and diploid rice were the same except some sites with three pair of primers preferably polymorphic and specific bands amplified in the different ploidy rice. The consequences of MSAP suggested that the total methylation ratio in autotetraploid rice （24.0%） was significantly less than the diploid rice （28.15%）; The full methylation ratio and hemi- methylation ratio were different between the autotetraploid and diploid rices. The averaged full methylation rate and hemi- methylation rate were 6.24% and 22.03%, respectively for diploid rice, 7.44% and 16.61% for autotetraploid rice. The degree of methylation did not increase due to polyploidy, indicating that diploid and tetraploid DNA methylation of the same species of rice changed. The pattern changes of the DNA methylation in the rice of various ploidy was further analyzed, which showed that demethylation occurred in autotetraploid rice on an average of about 11.6% sites, methylations on about 24.11% sites, and the proportion of genes with methylation significantly higher than that with demethylation. The methylation of some functional genes could induce gene silencing to ease the impact of genome doubling dose effect. Fig 4, Tab 5, Ref 29

关 键 词：同源四倍体 二倍体水稻 甲基化 甲基敏感扩增多态性(MSAP) 

分 类 号：S511[农业科学—作物学]