Histone variants and modifications during abiotic stress response

Abstract

Plants have developed multiple mechanisms as an adaptive response to abiotic stresses, such as salinity, drought, heat, cold, and oxidative stress. Understanding these regulatory networks is critical for coping with the negative impact of abiotic stress on crop productivity worldwide and, eventually, for the rational design of strategies to improve plant performance. Plant alterations upon stress are driven by changes in transcriptional regulation, which rely on locus-specific changes in chromatin accessibility. This process encompasses post-translational modifications of histone proteins that alter the DNA-histones binding, the exchange of canonical histones by variants that modify chromatin conformation, and DNA methylation, which has an implication in the silencing and activation of hypervariable genes. Here, we review the current understanding of the role of the major epigenetic modifications during the abiotic stress response and discuss the intricate relationship among them.

Keywords: abiotic stress; acetylation; chromatin; epigenetics; histone; histone modification; histone variant; methylation.

Figure 1

Global and local changes in chromatin structure in response to abiotic factors, such as salt, limited water availability, cold, heat, and low-light. Global changes are distributed genome-wide, whereas local changes are directed to specific genomic regions, commonly associated with stress-responsive genes.

Figure 2

Differences in the amino acid sequence of the members of the histone H3 family in Arabidopsis thaliana. The length of each variant’s amino acid sequence is indicated in black.

Figure 3

Summary of the histone PTMs in the nucleosome’s core histones in Arabidopsis. The PTMs detected are color-coded as indicated. Those involved in the abiotic stress response are highlighted in red.