NaCl胁迫对留兰香基因组DNA及其甲基化的影响

盐胁迫制约农业生产的因素之一。本研究以留兰香为材料，对氯化钠处理对留兰香生长发育和生理生化反应的影响，以及基因组DNA的甲基化水平和模式进行了研究。结果表明，氯化钠处理20天后，随着盐浓度的升高，叶绿素的含量逐渐降低，MDA和脯氨酸含量逐渐增大。AFLP分析表明，处理组与对照组之间未发现特异片段，基因组序列未发生变异。MSAP分析表明，50mmol/LNaCl 处理会引起全基因组DNA的甲基化水平降低，而100和150mmol/L NaCl则诱导了全基因组DNA的甲基化水平升高；与对照相比，50、100和150 mmol/L NaCl处理后DNA甲基化和去甲基化比率分别为4.35%、9.93%、12.46%和12.73%、13.12%、20.54%。

Effects of Salt on DNA Methylation of Menthae spicatae L.

The influence of salinity on spearmint growth and physiological and biochemical reactions, and the effects on genomic DNA and DNA methylation. Spearmint seedlings were grown on MS medium supplied with NaCI （0, 50, 100 and 150 mmol/L, respectively） for 20 days. Genomic DNA was extracted from leaves. The amplified fragment length polymorphisms （AFLP） and methylation sensitive amplification polymorphism （MSAP） was used to study the genetic and epigenetic stability. The chlorophyll content was significantly reduced, whereas the MDA and Pro content increased as the concentration of salt increased when the Mentbae spieatae L. seedlings were treated by NaCl for 20 days. AFLP technique did not detect any sequence variation; this meant that there was no difference in the genomic DNA polymorphism existed. The level of DNA methylation was reduced with concentrations of 50 mmol/L NaCl treatment and increased with concentrations of 100 and 150 mmol/L NaCI treatment; the ratio of methylation and demethylation of genomic DNA of the seedlings treated with 50, 100, and 150 mmol/L NaCl was 4.35%, 9.93%, 12.46% and 12.73%, 13.12%, 20.54%, respectively. The growth and physiological and biochemical reactions of Menthae spicatae L. had changed with NaCl treatment. Salt could not impact the genomic DNA sequence; however, it could result in the variation of DNA methylation.