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.
Numerous specimens stored in natural history collections have been involuntarily preserved together with their associated microbiomes. We propose exploiting century-old soils occasionally found on the roots of herbarium plants to assess the diversity of ancient soil microbial communities originally associated with these plants. We extracted total DNA and sequenced libraries produced from rhizospheric soils and roots of four plants preserved in herbaria for more than 120 years in order to characterise the preservation and taxonomic diversity that can be recovered in such contexts. Extracted DNA displayed typical features of ancient DNA, with cytosine deamination at the ends of fragments predominantly shorter than 50 bp. When compared to extant microbiomes, herbarium microbial communities clustered with soil communities and were distinct from communities from other environments. Herbarium communities also displayed biodiversity features and assembly rules typical of soil and plant-associated ones. Soil communities were richer than root-associated ones with which they shared most taxa. Regarding community turnover, we detected collection site, soil versus root and plant species effects. Eukaryotic taxa that displayed a higher abundance in roots were mostly plant pathogens that were not identified among soil-enriched ones. Conservation of these biodiversity features and assembly rules in herbarium-associated microbial communities indicates that herbarium-extracted DNA might reflect the composition of the original plant-associated microbial communities and that preservation in herbaria seemingly did not dramatically alter these characteristics. Using this approach, it should be possible to investigate historical soils and herbarium plant roots to explore the diversity and temporal dynamics of soil microbial communities.
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.
Aristolochic acid I (AAI), the predominant compound in Aristolochiaceae plants and Asarum species, is a widespread environmental contaminant capable of accumulating in soil, contaminating water and crops, ultimately entering the human body. Its nephrotoxic, carcinogenic, and reproductive toxic effects pose significant health concerns. This study investigates the impact of maternal AAI exposure on meiotic prophase I (MPI) during early fetal oogenesis. Pregnant mice were orally administered AAI at doses of 0.03125, 0.125, and 1 mg/kg from 14.5 to 16.5 dpc, with fetal ovaries collected at 17.5 dpc. AAI exposure induced meiotic defects in fetal oocytes, including delayed progression of MPI, increased DNA damage, and impaired homologous recombination. Furthermore, AAI induced oxidative stress, reduced mitochondrial membrane potential and triggered apoptosis, leading to a diminished ovarian reserve in neonatal ovaries. Mechanistically, these defects were mediated by heat shock proteins which altered protein-protein interactions crucial for DNA repair. Given the pivotal role of early oogenesis in determining female fertility and ensuring the health of offspring, these findings underscore the potential reproductive risks of AAI exposure during pregnancy. This study highlights the urgent need for greater awareness of foodborne contaminants and the implementation of preventative measures to mitigate maternal AAI exposure, thereby safeguarding offspring fertility and health.
Currently, there is a growing concern for human health with the rise of environmental pollution. Water contamination and health problems had been understood. Sanitation-related health issues have been overcome in the greater part of the world. Progressive industrialization has caused a number of new pollutants in water and in the atmosphere. It is a growing concern for the human health, especially upon the reproductive health. Current researchers provide a strong association between the rising concentrations of ambient pollutants and the adverse health impact. Furthermore, the pollutants have the adverse effects upon reproductive health as well. Major concern is for the health of a pregnant woman and her baby. Maternal-fetal inflammatory response due to the pollutants affects the pregnancy outcome adversely. Preterm labor, fetal growth restriction, intrauterine fetal death, and stillbirths have been observed. Varieties of pathological processes including inflammation, endocrine dysfunction, epigenetic changes, oxidative and nitrosative stress, and placental dysfunction have been explained as the biological plausibility. Prospective studies (systematic review and meta-analysis) have established that exposure to particulate matters (PM) and the nanoparticles (NP) leads to excessive oxidative changes to cause DNA mutations, lipid peroxidation and protein oxidation. Progressive industrialization and emergence of heavy metals, micro- (MP) and nanoparticles (NP) in the atmosphere and in water are the cause for concern. However, most of the information is based on studies from industrialized countries. India needs its own country-based study to have the exact idea and to develop the mechanistic pathways for the control.
The application of uranium (U) in the nuclear energy and defense industry has driven U mining activities, leading to subsequent U contamination. Understanding the toxicity and detoxification mechanism of U in plants is crucial for enhancing the efficiency of phytoremediation efforts in U-contaminated soils. The present study investigated the toxicity of uranium (U) in radish and its impact on physiological and molecular responses. The application of U (5-25 mu M) for 3 days significantly inhibited the elongation of radish lateral roots, and the lateral root length decreased by 35.6%-60.7% compared with the control. Under U stress, radish root tip meristem cells suffered DNA damage, fortunately the cells remained viable. To repair damaged DNA, the expression of genes involved in DNA repair (e.g. RAD2, XPC, BLM) was up-regulated, and the expression of genes involved in cell cycle was down-regulated (e.g. CYCB, CDKB). Under U stress, the expression of respiratory burst oxidase homologs (RBOHs) genes in radish roots up-regulated, which caused ROS burst, and then enhanced autophagy by promoting the expression of autophagy related genes (ATGs). Simultaneously, the glutathione (GSH) content increased, and the gene expression levels and activities of antioxidant enzymes (e.g. catalase) were increased, which enhanced the antioxidant capacity of root cells. Moreover, ubiquitin-proteasome system (UPS) (e.g. E3 ligase genes NEDD4) was involved in the activation of DNA repair, GSH synthesis and autophagy. In summary, DNA repair, autophagy, and antioxidant systems were activated in radish roots, which promoted the survival of apical meristem cells under U stress.
Despite its proven high toxicity, unsymmetrical dimethylhydrazine (UDMH) continues to be used in rocket technology and some other areas of human activity. In this work, the ability of plant-bacterial consortia to reduce the genotoxicity of UDMH and its incomplete oxidation products was investigated. Genotoxicity was assessed using a specific lux-biosensor, Escherichia coli MG1655 pAlkA-lux, which emits stronger light when cellular DNA is alkylated. For microbiological biodegradation, the Bacillus subtilis KK1112 strain was isolated from the soil via a two-stage selection process for resistance to high UDMH concentrations exceeding 5000 MAC. This strain's ability to biodegrade UDMH was demonstrated, as treatment of UDMH-polluted medium with KK1112 resulted in reduced DNA alkylation. A synergistic reduction in the DNA-alkylating potency of UDMH oxidation products was studied under the combined application of bacteria KK1112 and plant seedlings: Bromus inermis Leyss, Medicago varia Mart. and Phleum pratense L. The greatest effect was achieved when bacteria were used in combination with B. inermis. KK1112 cells accelerated seedling development and mitigated UDMH-induced growth inhibition. The findings suggest that the consortium of KK1112 and B. inermis has a great potential for remediation of UDMH-polluted soils in arid climatic zones.
This study investigated the sub-lethal effects of four commercial fungicides-two foliar (Amistar (R) Xtra and Mirador (R)) and two ear fungicides (Prosaro (R) and Icarus (R))-applied alone and in combination to wheat crops on caged earthworms (Eisenia fetida). We measured biomarkers that included detoxification responses (glutathione S-transferase, GST), oxidative stress levels (lipid peroxidation, LPO, and catalase, CAT), DNA damage (comet assay), energy reserves (lactate dehydrogenase, LDH), and immune response (lysozyme activity, LYS). The absence of significant differences in catalase and lipid peroxidation levels suggested no oxidative stress due to fungicide exposure. However, the foliar fungicide Amistar (R) Xtra induced the highest GST activity and DNA fragmentation, suggesting synergistic effects between its active ingredients and undisclosed co-formulants. Similar effects observed with the Amistar (R) Xtra-Prosaro (R) mixture confirmed the greater toxicity of Amistar (R) Xtra. This study provides novel insights into the sub-lethal effects of single and combined commercial fungicides on a standard toxicity test organism, shedding light on the ecological implications of fungicide use in agroecosystems and reinforcing the need for pesticide reduction.
Superfund sites are where soil, air, and water are polluted with hazardous materials. Individuals residing and working in these areas are often exposed to metals and other hazardous materials, leading to many adverse health outcomes, including cancer. While individuals are often exposed to multiple chemicals simultaneously, the combined effect of such exposures remains largely unexplored. Here, we investigated the toxicity of metal mixtures in five categories of in vitro assays measuring cytotoxicity, oxidative stress, genotoxicity, cytokine release, and angiogenesis. After testing these mixtures in primary cells and cell lines, we discovered that the nickel/arsenic/cadmium and beryllium/arsenic/cadmium combinations exhibited higher cytotoxicity than their individual compounds, suggesting that the mixtures amplified the cytotoxic effect. To investigate the mechanism underlying their toxicity, we evaluated metal-induced oxidative stress, as oxidative stress is a common factor in most metal-related toxicities. Our results showed that cadmium-induced oxidative stress was increased in mixtures. Some mixtures that induced oxidative stress further increased DNA damage, inhibited DNA synthesis, and activated p53. In addition, some mixtures significantly increased interleukin-8 secretion and angiogenesis more than their component compounds. Our findings offer important insights into metal-related toxicity at Superfund sites.
The negative ramifications of invasive alien species (IAS) are considered the second-most cause of biodiversity extinction and endangerment after habitat modification. IAS movements are mainly anthropogenically driven (e.g., transport of shipping containers) and require fast detection to minimize damage and cost. The present study is the first to use molecular biosurveillance of international shipping containers to detect IAS and regulated species identification in Canada. Thirty-eight samples were collected from debris (soil, stems, seeds, individual specimens) found in containers arriving in Canada. A multi-marker approach using COI, ITS, ITS2, and 16S was used to identify four main taxonomic groups: arthropods, fungi, plants, and bacteria, respectively. Eleven IAS species were identified via metabarcoding based on environmental DNA samples, including two arthropods, six fungi, two plants, and one bacteria. The origin of the eDNA detected from each species was linked to their native distribution and country of origin, except for Lymantria dispar. Four physical specimens were also collected from shipping container debris and DNA barcoded, identifying three non-regulated species (two arthropods and one fungus). Altogether, these results demonstrate the importance of integrating molecular identification into current toolkits for the biosurveillance of invasive alien species and provide a set of validated protocols ready to be used in this context. Additionally, it reaffirms international shipping containers as a pathway for multiple invasive aliens and regulated species introduction in Canada. It also highlights the need to establish regular and effective molecular biosurveillance at the Canadian border to avoid new or recurrent invasions. Las ramificaciones negativas de las especies ex & oacute;ticas invasoras (EEI) se consideran la segunda causa de extinci & oacute;n y peligro de la biodiversidad despu & eacute;s de la modificaci & oacute;n del h & aacute;bitat. Los movimientos de EEI son impulsados principalmente por causas antropog & eacute;nicas (por ejemplo, transporte de contenedores de env & iacute;o) y requieren una detecci & oacute;n r & aacute;pida para minimizar da & ntilde;os y costos. El presente estudio es el primero en utilizar biovigilancia molecular de contenedores de env & iacute;o internacionales para detectar EEI y la identificaci & oacute;n de especies reguladas en Canad & aacute;. Se recolectaron treinta y ocho muestras de material (tierra, tallos, semillas, espec & iacute;menes individuales) encontrados en contenedores que llegaron a Canad & aacute;. Se utilizaron m & uacute;ltiples marcadores moleculares, COI, ITS, ITS2 y 16S, para identificar cuatro grupos taxon & oacute;micos principales: artr & oacute;podos, hongos, plantas y bacterias, respectivamente. Se identificaron once especies de EEI mediante matabarcoding basado en ADN ambiental, incluidos dos artr & oacute;podos, seis hongos, dos plantas y una bacteria. El origen del ADN ambiental detectado de cada especie estuvo vinculado a su distribuci & oacute;n nativa y pa & iacute;s de origen, excepto Lymantria dispar. Tambi & eacute;n se recolectaron cuatro espec & iacute;menes en los contenedores de env & iacute;o y se analizaron mediante c & oacute;digo de barras de ADN, identificando tres especies no reguladas (dos artr & oacute;podos y un hongo). En conjunto, estos resultados demuestran la importancia de integrar la identificaci & oacute;n molecular dentro de las herramientas actuales para la biovigilancia de especies ex & oacute;ticas invasoras y proporcionan un conjunto de protocolos validados listos para ser utilizados en este contexto. Adem & aacute;s, reafirma que los contenedores de transporte internacional son una v & iacute;a para la introducci & oacute;n de m & uacute;ltiples especies ex & oacute;ticas invasoras y especies reguladas en Canad & aacute;. Tambi & eacute;n destaca la necesidad de establecer una biovigilancia molecular peri & oacute;dica y eficaz en la frontera canadiense para evitar invasiones nuevas o recurrentes.