空间飞行对水稻CDA基因甲基化的诱变效应

DNA Methylation Changes on Cytidine Deaminase Gene of Rice Induced by Space Flight

为了研究空间飞行对植物CDA基因甲基化的影响,以第21颗返回式卫星搭载的水稻种子和地面对照为试验材料,采用亚硫酸盐处理测序的方法对水稻胞嘧啶脱氨基酶(RCDA)基因CpG簇以及第一外显子区域胞嘧啶甲基化进行检测。与地面对照相比,空间飞行导致RCDA基因第一外显子发生可遗传的高甲基化变化。半定量PCR检测显示空间飞行后RCDA基因表达水平下降。另外采用药物5-氮杂胞苷处理水稻使RCDA基因甲基化水平降低,同时检测到基因表达水平上升。结果说明,空间飞行能够对RCDA基因产生甲基化诱变效应,并且甲基化水平的变化与基因表达相关。本研究从表观遗传学角度探讨了空间飞行环境对植物诱变效应的机制。

In order to investigate the biological effects of space flight on CDA gene of plant,seeds of rice（ Oryza sativa）were placed on twenty- first science and technology experiment satellite. DNA methylation changes on rice cytidine deaminase gene（ RCDA） were detected by the method of bisulfite sequencing. DNA methylation changes on CpG cluster and first exon of RCDA showed that heritable hypermethylation were induced on first exon. Semiquantification PCR analysis showed decreasing expression of RCDA after space flight. At the same time,increasing expression of RCDA were observed when RCDA gene was hypomethylated by 5- azacytidine（ 5- azaC） treatment. These results suggest that space flight is mutagen which can induced DNA methylation changes on RCDA. Moreover,the DNA methylation changes were associated with gene expression. This study suggests the role of epigenetic mechanism in mutations of plant induced by space flight.