Recent Advances in Histone Methylation in Plant Adaptation to Salinity

Soil salinization represents one of the most severe abiotic constraints on global agricultural productivity, threatening crop yields and food security across increasingly large areas of cultivated land. Among the molecular mechanisms underlying plant physiological adaptation to salinity, histone methylation has emerged as a central epigenetic regulatory layer governing salt-responsive transcriptional reprogramming through the coordinated and opposing actions of histone methyltransferases, demethylases, and reader proteins at specific chromatin loci. Recent advances reveal how dynamic changes in activating marks, principally H3K4me3 and H3K36me3, and repressive marks, H3K9me2 and H3K27me3, orchestrate the activation of stress-responsive gene networks and the silencing of growth-incompatible programs under salt stress. How these modifications establish and sustain stress memory across somatic and transgenerational timescales is discussed. Recent technological advances, including single-cell epigenomics, CUT&RUN, CUT&Tag, and spatial transcriptomics, are assessed as future research priorities. The application of CRISPR/dCas9-based epigenome editing and epigenetic breeding strategies for improving crop salt tolerance is further explored.