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.

Mechanisms of Plant Epigenetic Regulation in Response to Plant Stress: Recent Discoveries and Implications

“…Chromatin and gene expression are regulated by histone modifications (HMs), which can either activate or repress gene expression ( Figure 2 ), depending on the type of HM and its location [ 78 ]. Research shows that HMs are dynamically regulated during plant stress responses.…”

Epigenetic regulation in plant salt stress response

“…Histone variants, deposited by specific histone chaperones, often confer special structural and functional features, and have important roles in plant development. H3.3, H2A.Z, and H2A.X are linked to an open chromatin state and active transcription, while H2A.W and H1 histones favor compacted heterochromatin and silent genomic regions [15].…”

“…Histone variants have been found to function in response to many external stimuli, including drought, light and water deficiency, extreme temperatures, as well as other regulatory processes [15]. Particularly, the occupation of H2A.Z in Arabidopsis has been decreased during salt stress to activate a salt-induced transcription factor gene AtMYB44 [16].…”

Identification of a highly drought-resistantpp7l hda6mutant

“…On the molecular level, responses to drought and other stresses are accompanied by large-scale changes in nuclear (e.g., Bashir et al, 2019), and plastid (Xu et al, 2023) gene expression. In addition, in recent years, histone modifications have been shown to be among the epigenetic mechanisms that control gene expression in response to abiotic stress (Luo et al, 2017; Nunez-Vazquez et al, 2022), in particular drought (Li et al, 2021), by altering chromatin accessibility. One of the histone modifications is histone acetylation which involves the addition of acetyl groups to histone proteins mediated by histone deacetylases (HDACs).…”

“…In Arabidopsis , HDA6 and HDA19 are the most extensively studied HDACs. Both participate in pathogen defense, regulation of flowering, senescence, and abiotic stress responses (Nunez-Vazquez et al, 2022), and both hda6 (Kim et al, 2017) and hda19 (Ueda et al, 2018) mutants show enhanced drought tolerance.…”