Liu Zhenlan, Wang Yongming, Shen Ye, Guo Wanli, Hao Shui, Liu Bao
Laboratory of Molecular Epigenetics, Northeast Normal University, Changchun 130024, China.
Plant Mol Biol. 2004 Mar;54(4):571-82. doi: 10.1023/B:PLAN.0000038270.48326.7a.
It has been demonstrated that insertion of foreign DNA into mammalian genome can profoundly alter the patterns of DNA methylation and transcription of the host genome. Introgression of alien DNA into plant genomes through sexual crossing and genetic engineering are commonly used in breeding, but it is not known if plant genomes have similar responses to alien DNA introgression as those of animals. Two stable rice lines with introgression from wild rice, Zizania latifolia, were analyzed for patterns of cytosine DNA methylation and transcription of a set of selected sequences, including cellular genes and transposable element (TE)-related DNA segments. In 21 of the 30 studied sequences, marked changes in DNA methylation and/or transcription were observed compared with those of the rice parent. In all analyzed sequences, the absence of Zizania homologues in the introgression lines was confirmed. No change in DNA methylation and expression patterns was detected in randomly selected individuals of the rice parent nor in two sibling lines without introgressed Zizania DNA. The changed methylation patterns in both introgression lines were stably maintained in all five randomly sampled individuals of a given line, as well as in selfed progenies of the lines. Changed patterns in methylation and expression were also found in an independently produced asymmetric somatic nuclear hybrid (SH6) of rice and Z. latifolia that involves a different rice genotype but also contains a small amount of Z. latifolia DNA integrated into the rice genome. Thus, we have demonstrated that alien DNA introgression into a plant genome can induce extensive alterations in DNA methylation and transcription of both cellular genes and TE-related DNA segments in a genotype-independent manner.
已经证明，将外源DNA插入哺乳动物基因组可深刻改变宿主基因组的DNA甲基化模式和转录模式。通过有性杂交和基因工程将外源DNA渗入植物基因组在育种中普遍使用，但尚不清楚植物基因组对外源DNA渗入是否具有与动物类似的反应。对两个渗入野生菰DNA的稳定水稻品系进行分析，检测一组选定序列（包括细胞基因和转座元件（TE）相关DNA片段）的胞嘧啶DNA甲基化模式和转录情况。在所研究的30个序列中的21个序列中，与水稻亲本相比，观察到DNA甲基化和/或转录有明显变化。在所有分析的序列中，确认渗入系中不存在菰的同源物。在水稻亲本的随机选择个体以及两个没有渗入菰DNA的姊妹系中，未检测到DNA甲基化和表达模式的变化。在给定品系的所有五个随机取样个体以及品系的自交后代中，两个渗入系中改变的甲基化模式都得到稳定维持。在水稻和菰独立产生的不对称体细胞核杂种（SH6）中也发现了甲基化和表达模式的改变，该杂种涉及不同的水稻基因型，但也含有少量整合到水稻基因组中的菰DNA。因此，我们证明，将外源DNA渗入植物基因组可基因型非依赖方式诱导细胞基因和TE相关DNA片段的DNA甲基化和转录发生广泛改变。
