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.