极性生长的细胞中胞嘧啶甲基化的动态变化及其对GABA信号的响应

Dynamic Changes of Methylcytosine in Polarized Cell Growth and Their Response to GABA Signals

DNA胞嘧啶(C)的甲基化(5m C)在植物发育过程中具有重要的调节作用,多种环境因子如逆境胁迫、植物内/外源性因子等均会触发DNA甲基化的变化。为探讨γ-氨基丁酸(GABA)对植物发育的可能调节机制,本研究以极性生长的烟草花粉管和拟南芥根为材料,分析5m C的含量及其对GABA信号的响应。结果表明,1.0 mmol/L GABA能显著促进烟草花粉管和拟南芥根的极性生长;同时,GABA处理使烟草花粉管和拟南芥根的基因组中5m C含量显著降低、5-羟基胞嘧啶(5hm C)含量显著增加。5hm C是5m C去甲基化途径中的一个重要中间产物,本研究证实了GABA可以作为一种重要的外源信号调节DNA甲基化的动态变化。

DNA cytosine methylation（ 5m C） plays an important role in plant development. A variety of environmental factors,such as cellular endogenous and exogenous stress factors,can trigger changes in DNA methylation. To explore the possible mechanism regulated by γ-aminobutyric acid（ GABA） in plant development,we analyzed the content of 5m C and its response to GABA signals in the polarized growth of tobacco pollen tubes and Arabidopsis roots. Results showed that GABA（ 1. 0 mmol / L） significantly promoted the growth of tobacco pollen tubes and Arabidopsis roots,significantly decreased the content of 5m C in the genomic DNA of tobacco pollen tubes and Arabidopsis roots,and increased the content of 5-hydroxyl cytosine（ 5hm C）. 5hm C is an important intermediate of 5m C active demethylation via its oxidative metabolic pathway. Our results demonstrated that GABA,as an important exogenous signal,could regulate dynamic changes in DNA methylation.