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

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。

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

DNA cytosine methylation (5mC) 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 5mC 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 5mC in the genomic DNA of tobacco pollen tubes and Arabidopsis roots, and increased the content of 5-hydroxyl cytosine (5hmC). 5hmC is an important intermediate of 5mC active demethylation via its oxidative metabolic pathway. Our results demonstrated that GABA, as an important exogenous signal, could regulate dynamic changes in DNA methylation.