The barley senescence-associated gene HvS40 shows altered histone modifications during leaf senescence: euchromatic H3K9ac increases near its promoter and coding sequence, while heterochromatic H3K9me2 decreases. Bisulfite sequencing revealed no DNA methylation in this region, but a heavily methylated DNA island upstream of the translational start site in both mature and senescent leaves. DNA methylation decreased at one specific CpG motif in senescing leaves. Immunocytology showed senescence-associated changes in spatial distribution of heterochromatic H3K9me2 patterns in nuclei. These results demonstrate a senescence-specific mechanism altering histone modifications at HvS40 and heterochromatin distribution.

The authors developed Methylation Sensitive Amplification Polymorphism Sequencing (MSAP-Seq), replacing conventional MSAP's gel-based separation with Next Generation Sequencing (NGS) and automated analysis. The authors validated MSAP-Seq in Hordeum vulgare, enabling global sequence-based identification of DNA methylation changes. The authors confirmed this technique allows parallel analysis across hundreds of thousands of genomic sites, provides direct genomic localization and quantitative evaluation, and specifically targets gene-containing regions (covering three-quarters of all genes in large genomes per analysis). The authors demonstrated MSAP-Seq's simplicity, cost-effectiveness, and high-multiplexing capability make it affordable for DNA methylation analysis in crops with large, complex genomes.

This study demonstrates that DNA methylation and histone modifications enable barley adaptation to temperature stress. Methylation-sensitive amplification polymorphism analysis revealed that mild low temperature (14°C) induced more DNA methylation, while high temperature (38°C) promoted more DNA demethylation compared to control (22°C). HT stress significantly elevated H3K9ac and H3K4me3 levels versus MLT, leading to chromatin loosening and gene expression activation. Transcriptome analysis showed more differentially expressed genes (DEGs) under HT than MLT. This study reveals epigenetic regulatory mechanisms underlying temperature stress responses in barley.

This study investigated spatial distribution of epigenetic modifications in Hordeum vulgare root apical meristem using immunostaining. Tissue-specific patterns of H4K5ac, H3K4me2, H3K9me2, and DNA methylation (5mC) were established. The lateral root cap showed highest H3K9me2 and 5mC levels. Epidermis nuclei at the proximal meristem-elongation zone boundary exhibited peak 5mC and H3K9me2. Vascular tissues displayed maximal H4K5ac. Cytoplasmic histone modifications occurred tissue-specifically. This immunolocalization provides topographic context for epigenetic markers during root development.

This study identified two barley Type I-like MADS-box genes showing DNA methylation differences in their upstream and downstream regulatory regions during different seed developmental stages and after exogenous ABA application. These methylation variations are suggestive of epigenetic regulation of gene expression.

High-resolution detection of phosphorylated histone H3 at serine 10 in mitotic barley chromosomes for scanning electron microscopy was shown using a novel application of indirect immunogold labeling with Nanogold. This method permits localization and quantification of signals in a three-dimensional context. Because the chromosome structure is well preserved, characterization of binding sites (chromomeres, parallel matrix fibers, solenoids), currently in the realm of nanometer decades, is possible. Quantification and three-dimensional localization of labels is possible with stereoscopic analysis. Limitations of the method pertain to the challenges in preservation of chromosome ultrastructure, accessibility of immunoreactants into the fixed chromatin and unspecific labeling. The differences between silver and gold enhancement and the current status of labeling efficiency are addressed.

Histone H3 phosphorylation at threonine 3 (H3T3ph) and threonine 32 (H3T32ph) exhibits conserved spatiotemporal patterns during mitosis and meiosis. In large-genome species (Secale cereale, Vicia faba, Hordeum vulgare), phosphorylation initiates at prophase (mitosis) and diakinesis (meiosis I), with dephosphorylation in late anaphase. Arabidopsis thaliana (small genome) shows earlier dephosphorylation at anaphase. During metaphase (mitosis) and metaphase I, both modifications distribute along entire chromosomes. In meiosis II, H3T3ph localizes strictly to pericentromeric domains, while H3T32ph occurs along chromosome arms across all species.

Epigenetic processes are highly dynamic during barley endosperm development. The repressive H3K27me3 modification is globally reduced in endosperm tissues and at specific genes regulating development and storage compounds.