As the global population continues to grow, achieving ecological sustainability and ensuring food production have become urgent challenges. Among various environmental stresses, heavy metals, particularly cadmium (Cd), pose a significant threat to plant growth and development. Breeding cadmium-resistant crop varieties that minimize Cd accumulation is therefore crucial for promoting sustainable agriculture. In response to Cd stress, plants undergo a series of regulatory mechanisms, including DNA methylation, chromatin remodeling, and histone acetylation, to mitigate cellular damage. Understanding the epigenetic responses of plants to cadmium stress is a key research area that holds substantial significance for both agriculture and environmental biology. This article reviews the current research on plant responses to cadmium stress and the underlying mechanisms of their epigenetic responses, aiming to provide theoretical insights for analyzing the epigenetic mechanisms of heavy metal stress in major crops. We can leverage genomics, single-cell sequencing, stereo-seq, and other advanced technologies in conjunction with epigenomics, plant genetics and molecular biology techniques to conduct comprehensive and in-depth studies on the epigenetic changes that occur in plants following Cd exposure. Systematically elucidating the molecular mechanisms by which plants perceive and respond to Cd stress will aid in the development of more effective bioremediation strategies for heavy metal-contaminated soils and facilitate.

Coal mining has significant economic and environmental implications. The extraction and combustion of coal release harmful chemicals and dust, impacting air, soil, and water quality, as well as natural habitats and human health. This study aimed to investigate the association between global DNA methylation, DNA damage biomarkers (including telomere length), and inorganic element concentrations in the blood of individuals exposed to coal mining dust. Additionally, polycyclic aromatic hydrocarbons were analyzed. The study included 150 individuals exposed to coal mining and 120 unexposed controls. Results showed significantly higher global DNA hypermethylation in the exposed group compared to controls. Moreover, in the exposed group, micronucleus frequency and age showed a significant correlation with global DNA hypermethylation. Blood levels of inorganic elements, including titanium, phosphorus, sodium, aluminum, iron, sulfur, copper, chromium, zinc, chlorine, calcium, and potassium, were potentially associated with DNA methylation and oxidative damage, as indicated by comet assay results. Furthermore, exposure to polycyclic aromatic hydrocarbons such as fluoranthene, naphthalene, and anthracene, emitted in mining particulate matter, may contribute to these effects. These findings highlight the complex interplay between genetic instability, global DNA hypermethylation, and environmental exposure in coal mining areas, emphasizing the urgent need for effective mitigation strategies.

This study explored morphological, physiological, molecular, and epigenetic responses of tomatoes (Solanum lycopersicum) to soil contamination with polyethylene nanoplastics (PENP; 0.01, 0.1, and 1 gkg-1 soil). The PENP pollution led to severe changes in plant morphogenesis. The PENP treatments were associated with decreased plant biomass, reduced internode length, delayed flowering, and prolonged fruit ripening. Abnormal inflorescences, flowers, and fruits observed in the PENP-exposed seedlings support genetic changes and meristem dysfunction. Exposure of seedlings to PENP increased H2O2 accumulation and damaged membranes, implying oxidative stress. The PENP treatments induced activities of catalase (EC1.11.1.6), peroxidase (EC1.11.1.7), and phenylalanine ammonia-lyase (EC4.3.1.24) enzymes. Soil contamination with PENP also decreased the net photosynthesis, maximum photosystem efficiency, stomatal conductance, and transpiration rate. The nanopollutant upregulated the expression of the histone deacetylase (HDA3) gene and R2R3MYB transcription factor. However, the AP2a gene was down-regulated in response to the PENP treatment. Besides, EPNP epigenetically contributed to changes in DNA methylation. The concentrations of proline, soluble phenols, and flavonoids also displayed an upward trend in response to the applied PENP treatments. The long-term exposure of seedlings to PENP influenced fruit biomass, firmness, ascorbate, lycopene, and flavonoid content. These findings raise concerns about the hazardous aspects of PENP to agricultural ecosystems and food security.

Mercury (Hg) is recognized as a significant global pollutant, particularly in soils subjected to high anthropogenic activities, such as industrial emissions, agricultural runoff, and mining operations. As Hg contamination in the environment continues to rise, it has become increasingly critical to monitor its detrimental effects on ecosystems and living organisms. To address this concern, the current study focused on assessing the impacts of various concentrations of Hg [0 (Control; Tween 20-containing sterile water), 250, 500, 750, and 1000 UM HgCl2] on the genetic and epigenetic integrity of maize (Zea mays). Specifically, the study investigated DNA damage, DNA methylation patterns, and LTR retrotransposon polymorphism using molecular marker techniques, including Randomly Amplified Polymorphic DNA (RAPD), Coupled Restriction Enzyme Digestion-Random Amplification (CRED-RA), and Inter-Retrotransposon Amplified Polymorphism (IRAP), respectively. The results demonstrated that exposure to high doses of Hg led to a decrease in DNA methylation and a reduction in genomic template stability (GTS%), indicating a destabilization of genomic structure. In contrast, LTR retrotransposon polymorphism increased, suggestingheightened genomic variability due to Hg stress. These findings underscore the genotoxic and epigenetic effects of Hg, with evidence pointing to its ability to alter DNA methylation and activate retrotransposons, which may contribute to genome instability. Furthermore, the observed changes in DNA methylation and retrotransposon activity highlight their potential as reliable biomarkers for assessing exposure to chemical pollutants like Hg in plants. These biomarkers could play a key role in environmental monitoring and in understanding how plants respond to heavymetal stress at the molecular level, offering insights into both short-term and long-term genetic and epigenetic consequences.This study not only advances our understanding of Hg's impact on maize but also reinforces the need for ongoing research into the broader implications of heavy metal exposure on plant genomes and their adaptive responses