Epigenetic Responses to Heavy Metal Stress in Plants

Epigenetics refers to heritable changes in gene expression that occur without altering the DNA sequence. DNA methylation, chromatin alterations and non-coding RNAs are all recognized as epigenetic modulators of gene expression. Epigenetic alteration is an effective approach for plants to face environmental limitations and share the same adaptive strategy with their progeny through transgenerational inheritance. Epigenetic modifications affect cytosine and adenine DNA base modifications, cellular non-coding RNAs, remodeling histone variations and covalent histone tail modifications. Since some of these epigenetic alterations have been demonstrated to be long-lasting, they might influence the stress tolerance and stress memory of the progeny. This chapter describes DNA methylation, histone modification and non-coding RNA mechanisms to cope with various heavy metal stress in plants. Soil contamination with heavy metals is a significant issue in many locations across the world. These heavy metals are harmful to almost every living species, reducing food production and endangering human health. Crop plants exposed to high quantities of these metals suffer from disrupted mineral homeostasis, lower photosynthetic efficiency, inhibited cell division, oxidative stress, genotoxic effects and subsequently restricted growth. Heavy metals, a type of environmental contaminant, can directly affect gene expression by binding to metal response elements in gene promoters.