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高羊茅是一种重要的禾本科牧草,尽管其具有良好的耐寒耐热性,但其生长发育过程受外界氮素浓度的直接影响。DNA甲基化作为一种表观遗传调控方式在植物抵御逆境胁迫中起到至关重要的作用。本研究以高羊茅为试验材料,经无氮胁迫15 d后,以未经氮胁迫为对照,对基因组DNA甲基化的变化进行甲基化敏感扩增多态性(MSAP)分析。结果表明:无氮处理15 d后,植株生长受到强烈地抑制,且叶片大面积发黄;MSAP分析选用12对选扩引物,共检测到725个基因位点,其中发生甲基化和去甲基化的位点占16.4%;对照组和氮胁迫组总甲基化水平分别是65.56%和65.47%,显示氮胁迫15 d高羊茅基因组DNA总的甲基化水平未发生显著变化。对15条标记带进行克隆并测序,成功获得14条不同变化类型的序列,这些序列与禾本科植物具有较高的同源性,推测氮胁迫下的高羊茅基因组甲基化可能发生在编码区域。综上,高羊茅对环境的适应性调节可能与氮胁迫诱导的甲基化的变化有关。
Tall fescue is an important gramineous pasture, and its growth and development are directly affected by the external nitrogen concentration, despite its good cold and heat tolerance. DNA methylation plays an important role in plant defense against stress as an epigenetic regulation. In this study, the high-fescue was used as experimental material. Methylation-sensitive amplification polymorphism (MSAP) analysis was used to analyze the genomic DNA methylation changes after 15 days of no nitrogen stress. The results showed that after 15 days of nitrogen-free treatment, the growth of plants was strongly inhibited and the leaves were yellow on a large area. In the MSAP analysis, 12 pairs of primers were selected and 725 loci were detected, of which methylation and demethylation The total methylation level of genomic DNA was 16.4% in the control group and 65.56% and 65.47% in the nitrogen stress group, respectively. The results showed that there was no significant change in the total methylation level of genomic DNA of Tall Fescue under nitrogen stress for 15 d. Fifteen marker bands were cloned and sequenced, and 14 sequences with different variation types were successfully obtained. These sequences shared high homology with gramineous plants. It was presumed that methylation of Tall Fescue under nitrogen stress might occur in coding area. In conclusion, adaptability of tall fescue to the environment may be related to the change of methylation induced by nitrogen stress.