Figure 1.

DNA methylation and heavy metal stresses. Under heavy metal stress alone or in concert, DNA methylation may play a role in regulating plant responses to heavy metals through at least two mechanisms. The first mechanism is hypermethylation, a defense strategy of plants that can prevent genomic instability and protect DNA from possible damage by heavy metal products, allowing plants to survive in extreme environments. The second mechanism involves gene expression regulation, which is not limited to the promoter regions of genes, but also their coding regions.