菊花组织培养继代过程中的DNA甲基化变化

The Variation of DNA Methylation Variation During Successive Transfer Culture of Chrysanthemum (Dendranthema×grandiflorum)

采用MSAP(甲基敏感扩增多态性)方法对菊花(Dendranthema×grandiflorum)组织培养继代过程中的DNA甲基化情况进行了分析。结果发现,3个单芽系的组培苗较田间材料均有DNA甲基化增加和减少现象,采用7对引物,共扩增出929条带,各单芽系DNA甲基化变异率分别为8.929%、8.902%和8.986%。继代材料较母体均有甲基化变异发生,且变异类型中DNA甲基化减少的比例高于甲基化增加的比例,随着继代次数的增加,两种变异间的差异逐渐减小,比例相近。同时在同一单芽系内的不同次继代个体间有DNA甲基化变化现象,对5次继代的180个个体研究发现,带型变化中18.38%的带型不一致,2.99%为一个或两个个体发生了变化,仅有1.72%在发生变化后趋于稳定,另外10.68%的带型呈现不稳定的随机变化。

This study analysised the DNA methylation statistic during the successive transfer culture of chrysanthemum （Dendranthema × grandiflorum） by MSAP （methylation sensitive amplified polymorphism） technique. The results indicated that three single shoot system of the tissue culture seedling had distinct DNA hypermethylation and hypomethylation variety compared to the field materials. Nine hundred and twenty-nine fragments were amplified using 7 pairs of selective primers, and the mutation rates were 8. 929%, 8. 902% and 8.986% , respectively. All the successive transfer materials had DNA methylation variety compared to the parent materials. During the variation, hypomethylation were more than hypermethylation. Along with the successive transfer culture, the diversity between the two variety pattern was smaller, and the proportion was almost similar. Meanwhile, the different individual of each single shoot system also existed DNA variation phenomenon. Among the 180 individuals of quintic successive transfer culture, 18.38% bands pattern was not identical during the variational bands pattern, 2.99% was one or two individual variation, 1.72% bands pattern was stabilization after variety, while 10. 68% showed unstable stochastic variety.