Histone acetyltransferases as integrative epigenetic regulators of plant abiotic stress responses

This article reviews how histone acetyltransferases (HATs) regulate plant responses to salt, drought, temperature, and light/UV-B stresses through histone and non-histone acetylation. Abiotic stresses, including drought, salinity, temperature extremes, and light stress, severely constrain plant growth and crop productivity. Histone acetyltransferases (HATs) are important epigenetic regulators that connect environmental signals with chromatin remodeling and stress-responsive gene expression. In this review, we summarize the classification and structural features of major plant HAT families, including GCN5-related N-acetyltransferase (GNAT), MOZ, YBF2/SAS3, SAS2, and TIP60 (MYST), TATA-binding protein-associated factor II 250 (TAF_II250), and E1A-binding protein p300/cAMP-response element-binding protein (p300/CBP)-related proteins, and discuss how their substrate specificity is influenced by catalytic domains, interacting proteins, chromatin context, and subcellular localization. We then synthesize current evidence for the roles of HATs in plant responses to salt, drought, temperature, and light stresses, with emphasis on their functions in histone acetylation, non-histone acetylation, transcription factor recruitment, and physiological stress adaptation. We further discuss conserved and species-specific mechanisms, context-dependent regulatory patterns, and crosstalk between HATs and other epigenetic or metabolic pathways. Finally, we highlight unresolved questions regarding substrate selection, spatiotemporal regulation, non-model species, and multi-stress responses. This review provides an integrated framework for understanding HAT-mediated stress regulation and offers perspectives for improving crop stress resilience through epigenetic approaches.