重金属Cr6+胁迫下小麦幼苗DNA 5-MeC含量的改变

Effects of Cr6+ stress on 5-MeC content of DNA in wheat seedlings

关键词:  小麦  Cr⁶⁺  5-MeC  HPLC

Key words:  wheat  Cr⁶⁺  5-MeC  HPLC

摘要:

运用高效液相色谱法(HPLC)研究了3 d龄和10 d龄小麦幼苗在5～100 mg/L Cr⁶⁺胁迫下根系和地上部分DNA 5-甲基胞嘧啶(5-MeC)含量的变化。方法:色谱柱为Hypersil BDS-C18键合柱(5 μm,150×4.6 mm I.D.); 流动相由5%甲醇,4.75 mmol/L己烷磺酸钠,0.2%三乙醇胺组成,三蒸水配制,pH值为5.5; 流速为0.7 mL/min; 检测波长为273 nm。结果发现:除100 mg/L Cr⁶⁺降低了3 d龄小麦幼苗根系DNA 5-MeC的百分含量外,所试不同浓度Cr⁶⁺均引起两苗龄幼苗叶片和根系DNA甲基化水平的上升; 3 d龄幼苗对Cr⁶⁺胁迫比10 d龄幼苗敏感,根系比地上部分敏感。结论:Cr⁶⁺胁迫引起的DNA甲基化水平改变可能影响到小麦幼苗的正常生长发育。

Abstract:

The effects of Cr⁶⁺ on the 5-methyl cytosine(5-MeC)contents in leaves and roots DNA in 3-day-old and 10-day-old wheat seedlings with 5-100 mg/L Cr⁶⁺treatment were determined by the reversed-phase high performance liquid chromatography(HPLC). The Hypersil BDS-C18 column(5 μm,150×4.6 mm I.D.)and mobile phase of 5% methanol,-4.75 mmol/L sodium hexanesulfonate, -0.2% triethanolamine-water,pH 5.5 at the flow rate of 0.7 mL/min was used. Detection was performed with UV detector at 273nm. The results showed that the 5-MeC contents in leaves and roots DNA in 3-day-old and 10-day-old wheat seedlings with Cr⁶⁺ concentration increased from 5 to100 mg/L were all higher than that in control,but the 5-MeC contents caused by 100 mg/L Cr⁶⁺was lower than that in control in the roots DNA in 3-day-old seedlings. And the results suggested that 3-day-old seedlings were more sensitive to Cr⁶⁺stress than 10-day-old seedlings, and the roots were more sensitive than the leaves. Therefore,the change of DNA methylation level caused by heavy metal Cr⁶⁺could have an effect on normal growth and development in wheat seedlings.