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Cadmium is commonly recognized as toxic to plant growth, low-level Cd has promoting effects on growth performance, which is so-called hormesis. Although Cd toxicity in wheat has been widely investigated, knowledge of growth response to a broad range of Cd concentrations, especially extremely low concentrations, is still unknown. In this study, the morphological, physiological, and biochemical performance of wheat seedlings to a wide range of Cd concentrations (0–100 µΜ) were explored. Low Cd treatment (0.1–0.5 µM) improved wheat biomass and root development by enhancing the photosynthetic system and antioxidant system ability. Photosynthetic rate (Pn) was improved by 5.72% under lower Cd treatment (1 µΜ), but inhibited by 6.05–49.85% from 5 to 100 µΜ. Excessive Cd accumulation induced oxidative injury manifesting higher MDA content, resulting in lower photosynthetic efficiency, stunted growth, and reduction of biomass. Further, the contents of ascorbate, glutathione, non-protein thiols, and phytochelatins were improved under 5–100 µΜ Cd treatment. The ascorbate peroxidase activity in the leaf showed a hormetic dose–response characteristic. Correlation analysis and partial least squares (PLS) results indicated that antioxidant enzymes and metabolites were closely correlated with Cd tolerance and accumulation. The results of the element network, correlation analysis, and PLS showed a crucial role for exogenous Cd levels in K, Fe, Cu, and Mn uptake and accumulation. These results provided a deeper understanding of the hormetic effect of Cd in wheat, which would be beneficial for improving the quality of hazard and risk assessments. [ABSTRACT FROM AUTHOR]

Summary Rice grains typically contain relatively high levels of toxic arsenic (As) but low levels of essential micronutrients. Biofortification of essential micronutrients while decreasing As accumulation in rice would benefit human nutrition and health. We generated transgenic rice expressing a gain‐of‐function mutant allele astol1 driven by the OsGPX1 promoter. astol1 encodes a plastid‐localized O‐acetylserine (thiol) lyase (OAS‐TL) with Ser189Asn substitution (OsASTOL1S189N), which enhances cysteine biosynthesis by forming an indissociable cysteine synthase complex with its partner serine acetyltransferase (SAT). The effects on growth, As tolerance, and nutrient and As accumulation in rice grain were evaluated in hydroponic, pot and field experiments. The expression of OsASTOL1S189N in pOsGPX1::astol1 transgenic lines enhanced SAT activity, sulphate uptake, biosynthesis of cysteine, glutathione, phytochelatins and nicotianamine, and enhanced tolerance to As. The expression of OsASTOL1S189N decreased As accumulation while increased the accumulation of multiple macronutrients (especially sulphur, nitrogen and potassium) and micronutrients (especially zinc and selenium) in rice grain in a pot experiment and two field experiments, and had little effect on plant growth and grain yield. Our study provides a new strategy to genetically engineer rice to biofortify multiple essential nutrients, reducing As accumulation in rice grain and enhancing As tolerance simultaneously. [ABSTRACT FROM AUTHOR]

The issue of heavy metals (HMs) contamination poses a significant challenge in the environment, exerting a severe impact on the growth and productivity of crops. Cadmium (Cd) is specifically identified as the seventh heavy metal among the top 20 pollutants, primarily due to its elevated phytotoxicity and its solubility in water. In the current study, foliar application of glycine betaine (GB) (500 µmol) investigated the toxic effects of cadmium in maize plants subjected to two Cd concentrations (50 and 100 µmol) as CdCl2. The maize plants exposed to Cd stress exhibited a massive reduction in growth, biomass, photosynthetic pigments [chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids, and total pigments], gas exchange parameters [transpiration rate (Tr), net photosynthetic rate (Pn), intracellular CO2 concentration (ci), and stomatal conductance (gs)], relative water content (RWC), and organic osmolytes content [total soluble protein (TSS), and total soluble sugar (TSS)]. These impacts were significant with the 100 µmol CdCl2 treatment. Moreover, Cd led to remarked increase in proline, nonenzymatic antioxidants levels [ascorbic acid (AsA) and glutathione (GSH)] as well as the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR). On the other hand, GB application efficiently relieved the Cd toxic impacts on maize and maintained higher growth criteria, gas exchange parameters, photosynthetic pigments, RWC, and organic osmolytes. In addition, the exogenous application of GB added more enhancement to the antioxidative system (enzymatic and nonenzymatic). These results imply that GB could significantly preserve maize growth under Cd toxicity conditions by maintaining photosynthetic characteristics, water status, and antioxidant system. This suggests an enhancement in the plant's resilience to stress induced by heavy metals. [ABSTRACT FROM AUTHOR]

Phytochelatin synthase (PCS) is a critical enzyme involved in heavy metal detoxification in organisms. In this study, we aim to comprehensively investigate the molecular and functional characteristics of the PCS1 gene from Nicotiana tabacum by examining its enzymatic activity, tissue-specific expression pattern, Cd-induced expression, as well as the impact on Cd tolerance and accumulation. The results demonstrated that the amino acid sequence of NtPCS1 shared a high similarity in its N-terminal region with PCS from other species. The enzymatic activity of NtPCS1 was found to be enhanced in the order Ag2+ > Cd2+ >Cu2+ > Pb2+>Hg2+ > Fe2+ > Zn2+. In addition, RT-PCR data indicated that NtPCS1 gene is constitutively expressed, with the highest expression observed in flowers, and that its transcript levels are up-regulated by CdCl2. When tobacco overexpressing NtPCS1 (PCS1 lines) were grown under CdCl2 stress, they produced more phytochelatins (PCs) than WT plants, but this did not result in increased Cd accumulation. However, in a root growth assay, the PCS1 lines exhibited hypersensitivity to Cd. The overexpression of NtPCS1 itself does not appear to be the primary cause of this heightened sensitivity to Cd, as the Arabidopsis thaliana Atpcs1 mutant overexpressing NtPCS1 actually exhibited enhanced tolerance to Cd. Furthermore, the addition of exogenous glutathione (GSH) progressively reduced the Cd hypersensitivity of the PCS1 lines, with the hypersensitivity even being completely eliminated. Surprisingly, the application of exogenous GSH led to a remarkably enhanced Cd accumulation in the PCS1 lines. This study enriches our understanding of the molecular function of the NtPCS1 gene and suggests a promising avenue for Cd tolerance through the heterologous expression of PCS genes in different species. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a biologically non-essential heavy metal, a major soil pollutant, and extremely harmful to plants. The phytohormone methyl jasmonate (MeJA) plays an important role in plant heavy-metal resistance. However, the understanding of the effects of MeJA supply level on alleviating Cd toxicity in plants is limited. Here, we investigated how MeJA regulated the development of physiological processes and cell wall modification in Cosmos bipinnatus. We found that low concentrations of MeJA increased the dry weight of seedlings under 120 µM Cd stress by reducing the transport of Cd from roots to shoots. Moreover, a threshold concentration of exogenous MeJA increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in plant roots, the concentration of Cd in the root cell wall, and the contents of pectin and hemicellulose 1 polysaccharides, through converting Cd into pectin-bound forms. These results suggested that MeJA mitigated Cd toxicity by modulating root cell wall polysaccharide and functional group composition, especially through pectin polysaccharides binding to Cd, with effects on Cd transport capacity, specific chemical forms of Cd, and homeostatic antioxidant systems in C. bipinnatus. [ABSTRACT FROM AUTHOR]

Plants have developed precise defense mechanisms against cadmium (Cd) stress, with vacuolar compartmentalization of Cd2+ being a crucial process in Cd detoxification. The transport of Cd into vacuoles by these cation / H+ antiporters is powered by the pH gradient created by proton pumps. In this study, the full-length cDNA of a vacuolar H+-pyrophosphatase (V-PPase) gene from Boehmeria nivea (ramie), BnVP1, was isolated using the rapid amplification of cDNA ends (RACE) method. The open reading frame (ORF) of BnVP1 is 2292 bp, encoding a 763 amino acid V-PPase protein with 15 predicted transmembrane domains. Sequence alignment and phylogenetic analysis revealed that BnVP1 belongs to the Type I V-PPase family. Quantitative RT-PCR assays demonstrated that BnVP1 expression was significantly higher in ramie roots than in shoots. Cd treatments markedly induced BnVP1 expression in both roots and leaves of ramie seedlings, with a more pronounced effect in roots. Additionally, BnVP1 expression was significantly upregulated by the plant hormone methyl jasmonate (MeJA). Heterologous expression of BnVP1 in transgenic Arabidopsis significantly enhanced V-PPase activity in the roots. The growth performance, root elongation, and total chlorophyll content of transgenic plants with high tonoplast H+-PPase (V-PPase) activity were superior to those of wild-type plants. Overexpression of BnVP1 reduced membrane lipid peroxidation and ion leakage, and significantly increased Cd accumulation in the roots of transgenic Arabidopsis seedlings. This study provides new genetic resources for the phytoremediation of Cd-contaminated farmland. [ABSTRACT FROM AUTHOR]

Thiol-peptides, such as glutathione and phytochelatins, are believed to play a crucial role in regulating metal micronutrient needs (in particular, copper, iron, and zinc), and in detoxifying their excessive amounts. This study provides insight into the mechanisms involved in detoxification, starvation, and physiological control of the aforesaid metals in the liverwort Marchantia polymorpha. The results show that the phytochelatin synthase activity in gametophytes of M. polymorpha is induced mainly by zinc, followed by copper, and iron. Interestingly, the amount of phytochelatins produced seems to be controlled by the enzyme activity, rather than by the expression level of its gene. Moreover, when gametophytes are deprived of zinc, copper, and iron, phytochelatin levels decrease, compared with normal nutrient supply. Phytochelatins and glutathione, on the other hand, appear to play a key role in detoxification of excess zinc, copper, and iron, particularly when these thiol-peptides are released extracellularly. This suggests a potential novel function for phytochelatins and glutathione as detoxifying compounds also in the extracellular environment. [ABSTRACT FROM AUTHOR]

Due to their stationary nature, plants are exposed to a diverse range of biotic and abiotic stresses, of which heavy metal (HM) stress poses one of the most detrimental abiotic stresses, targeting diverse plant processes. HMs instigate the overproduction of reactive oxygen species (ROS), and to mitigate the adverse effects of ROS, plants induce multiple defence mechanisms. Besides the negative implications of overproduction of ROS, these molecules play a multitude of signalling roles in plants, acting as a central player in the complex signalling network of cells. One of the ROS‐associated signalling mechanisms is the mitogen‐activated protein kinase (MAPK) cascade, a signalling pathway which transduces extracellular stimuli into intracellular responses. Plant MAPKs have been implicated in signalling involved in stress response, phytohormone regulation, and cell cycle cues. However, the influence of various HMs on MAPK activation has not been well documented. In this review, we address and summarise several aspects related to various HM‐induced ROS signalling. Additionally, we touch on how these signals activate the MAPK cascade and the downstream transcription factors that influence plant responses to HMs. Moreover, we propose a workflow that could characterise genes associated with MAPKs and their roles during plant HM stress responses. Summary statement: This review highlights the link between five heavy metals (HM) and their reactive oxygen species (ROS) signalling of the mitogen‐activated protein kinases (MAPK) pathway to stimulate downstream transcription factors that act as a mechanism for HM acclimation. The review likewise provides a proposed workflow to further elucidate heavy‐metal‐ROS induction of the MAPK pathway for HMs, such as arsenic, that have not been extensively examined in plant systems. [ABSTRACT FROM AUTHOR]

Drought stress can impair plant growth and development. Nitric oxide (NO), a gas signaling molecule, delays injuries caused by abiotic stress. This study explored the roles of NO during adventitious rooting in cucumber (Cucumis sativus L.) under drought stress. Our results found that 0.05% (W/V) polyethylene glycol 6000 (PEG) treatment significantly suppressed adventitious root formation, but 10 μM GSNO (a NO donor) treatment could significantly reverse the negative effect of drought stress. Under drought stress, MDA, H2O2 and O2·− accumulation were increased during rooting. Nevertheless, the application of exogenous NO decreased reactive oxygen (ROS) accumulation, revealing that NO might play an essential role in improving drought tolerance. Compared with PEG treatment, PEG + GSNO treatment enhanced the level of glutathione (GSH), ascorbic acid (AsA), and GSH/GSSG ratio, while decreasing glutathione disulfde (GSSG) content. In comparison with PEG treatment, PEG + GSNO treatment significantly increased the activity of antioxidant enzymes (APX, AAO, GR, and MDHAR) and the expression level of related enzyme genes (CsAPX, CsAAO, CsGR, and CsMDHAR). In addition, PEG + GSNO treatment also increased endogenous NO and S-nitrosothiol (SNO) content, nitrate reductase (NR) activity, and total S-nitrosylated proteins, and the expression of CsNR, while PEG + GSNO treatment decreased S-nitrosoglutathione reductase (GSNOR) activity, suggesting that protein S-nitrosylation might be involved in adventitious rooting under drought stress. In summary, our results indicate that NO could promote adventitious root formation under drought stress via regulating ascorbate glutathione (AsA-GSH) pathway cycle and protein posttranslational S-nitrosylation. [ABSTRACT FROM AUTHOR]

We investigated the influence of poly-glutamic acid (PGA) on ascorbic acid (AsA) and glutathione (GSH) metabolism in leaves of wheat seedlings under cadmium (Cd) stress. The results showed that Cd stress enhanced ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase, glutathione reductase, gamma-glutamylcysteine synthetase and L-galactono-1,4-lactone dehydrogenase activities, and increased AsA and GSH contents. Whereas Cd reduced AsA/dehydroascorbic acid (DHA) and GSH/oxidised glutathione (GSSG) ratios and increased malondialdehyde (MDA) content and electrolyte leakage (EL). Meanwhile, Cd stress improved Cd accumulation and nonphotochemical quenching (qN) and decreased soil and plant analyser development (SPAD) value, net photosynthetic rate (Pn), maximum photochemical efficiency of PSII (Fv/Fm), photochemical quenching (qP), quantum efficiency of PSII photochemistry (ΦPSII), wheat height and dry biomass. Compared to Cd alone, PGA plus Cd stress reinforced AsA and GSH metabolism via the above enzymes and increased AsA and GSH contents and their redox status. PGA plus Cd stress also decreased MDA content and EL. Besides, PGA plus Cd stress decreased Cd accumulation and increased SPAD value, Pn, qN, Fv/Fm, qP, ΦPSII, wheat height and dry biomass. Moreover, PGA alone showed positive effects on the indicators mentioned above. Our results clearly indicated that PGA enhanced wheat Cd tolerance by preventing Cd uptake and enhancing AsA and GSH metabolism. Therefore, PGA can be applied to enhance wheat Cd tolerance in production. [ABSTRACT FROM AUTHOR]

Heavy metal (HM) pollution, specifically cadmium (Cd) contamination, is a worldwide concern for its consequences for plant health and ecosystem stability. This review sheds light on the intricate mechanisms underlying Cd toxicity in plants and the various strategies employed by these organisms to mitigate its adverse effects. From molecular responses to physiological adaptations, plants have evolved sophisticated defense mechanisms to counteract Cd stress. We highlighted the role of phytochelatins (PCn) in plant detoxification, which chelate and sequester Cd ions to prevent their accumulation and minimize toxicity. Additionally, we explored the involvement of glutathione (GSH) in mitigating oxidative damage caused by Cd exposure and discussed the regulatory mechanisms governing GSH biosynthesis. We highlighted the role of transporter proteins, such as ATP-binding cassette transporters (ABCs) and heavy metal ATPases (HMAs), in mediating the uptake, sequestration, and detoxification of Cd in plants. Overall, this work offered valuable insights into the physiological, molecular, and biochemical mechanisms underlying plant responses to Cd stress, providing a basis for strategies to alleviate the unfavorable effects of HM pollution on plant health and ecosystem resilience.

The experiment aimed to explore the effects of adding exogenous glutathione on the photosynthesis and antioxidant enzyme activity of Medicago sativa in severely cadmium (Cd) polluted pasture areas. The materials for the experiment were Zhongmu No.1, WL525HQ, Gannong No.3, and Gannong No.9, with three groups set up: The control group (CK group, Hoagland culture solution), the Cd treatment group (Cd group, Hoagland + 15 mg/L Cd), and the combined treatment group (Cd + GSH group, Hoagland + 15 mg/L Cd + 25 mg/L GSH) for hydroponic experiments. The relative water content of leaves (RWC), chlorophyll content (SPAD), stomatal conductance (Gs), net photosynthetic rate (Pn), intercellular CO2 concentration (Ci), transpiration rate (Tr), as well as the content of malondialdehyde (MDA), proline (Pro), and antioxidant enzyme activity were measured. The results showed that compared with the Cd group, the RWC, SPAD, Gs, Pn, Ci, and Tr of each variety in the Cd + GSH group were all improved to some extent. Compared with the Cd group, the MDA content of each variety in the Cd + GSH group was significantly reduced (P<0.05), and the Pro content of WL525HQ, Gannong No.3, and Zhongmu No.1 was significantly reduced after the addition of exogenous GSH (P<0.05). Compared with the Cd group, the activities of peroxidase (POD) and ascorbate peroxidase (APX) in each variety of the Cd + GSH group were significantly reduced (P<0.05), the superoxide dismutase (SOD) activity of Gannong No.9 and Gannong No.3 was significantly reduced (P<0.05), and the activity of catalase (CAT) in WL525HQ, Gannong No.9, and Gannong No. 3 was significantly increased (P<0.05). The study indicates that the addition of exogenous GSH can alleviate the toxic effects of Cd on Medicago sativa in severely Cd-polluted pasture areas, reduce oxidative damage, and improve its adaptability, and there is a certain correlation between various physiological indicators of alfalfa. [ABSTRACT FROM AUTHOR]

To analyze the mechanism of copper accumulation in the marine alga Ulva compressa, it was cultivated with 10 μM of copper, with 10 μM of copper and increasing concentrations of a sulfide donor (NaHS) for 0 to 7 days, and with 10 μM of copper and a concentration of the sulfide acceptor (hypotaurine) for 5 days. The level of intracellular copper was determined as well as the level of glutathione (GSH) and phytochelatins (PCs) and the expression of metallothioneins (UcMTs). The level of intracellular copper in the algae treated with copper increased at day 1, slightly increased until day 5 and remained unchanged until day 7. The level of copper in the algae cultivated with copper and 100 or 200 μM of NaHS continuously increased until day 7 and the copper level was higher in the algae cultivated with 200 μM of NaHS compared to 100 μM of NaHS. In contrast, the level of intracellular copper decreased in the algae treated with copper and hypotaurine. The level of intracellular copper did not correlate with the level of GSH or with the expression of UcMTs, and PCs were not detected in response to copper, or copper and NaHS. Algae treated with copper and with copper and 200 μM of NaHS for 5 days were visualized by TEM and the elemental composition of electrondense particles was analyzed by EDXS. The algae treated with copper showed electrondense particles containing copper and sulfur, but not nitrogen, and they were mainly located in the chloroplast, but also in the cytoplasm. The algae treated with copper and NaHS showed a higher level of electrondense particles containing copper and sulfur, but not nitrogen, and they were located in the chloroplast, and in the cytoplasm. Thus, copper is accumulated as copper sulfide insoluble particles, and not bound to GSH, PCs or UcMTs, in the marine alga U. compressa. [ABSTRACT FROM AUTHOR]

To remedy Cd pollution in the ocean, macroalgae are used as a bioremediation tool because of their ability to absorb and accumulate Cd. Gracilaria bailinae has high economic and ecological value and can survive in Cd contaminated waters; however, the underlying molecular mechanisms remain unclear. In this study, physiological and biochemical indexes were analyzed after 1, 3, 5, or 7 days of Cd2+ exposure; further, the transcriptome of G. bailinae was examined after a 7-day exposure to a Cd2+ culture environment with Cd levels of 0 mg L-1 (cd1, control), 1 mg L-1 (cd2, low concentration), and 2.5 mg L-1 (cd3, high concentration). The results showed that in the cd2 group, G. bailinae maintained a stable RGR that did not differ significantly (P > 0.05) from that of the cd1 group. However, the soluble protein and MDA contents, as well as the activities of SOD, CAT and POD, were significantly increased (P< 0.05) compared to the cd1 group. No significant differences (P > 0.05) were found among the different Cd2+ stress durations. In contrast, compared with the cd1 group, the RGR, soluble protein content, SOD, CAT, and POD activities were significantly decreased (P< 0.05), while the MDA content was significantly increased (P< 0.05) in the cd3 group. Furthermore, significant differences (P< 0.05) were observed among the various tested Cd2+ stress durations within the cd3 group. Compared to the cd1 group, a total of 30,072 DEGs and 21,680 were identified in the cd2 and cd3 treatments, respectively. More up-regulated genes were found in cd2 group than in cd3 group. GO enrichment analysis showed that these genes were related to peptidase activity, endopeptidase activity, ion transport, peptide biosynthetic and metabolism. In addition, DEGs related to histidine metabolism and the stilbene, diarylheptane, and gingerol pathways were significantly up-regulated in the cd2 group compared to the cd3 group, which resulted in enhanced activities of antioxidant enzymes and promoted cell wall regeneration. The results of this study reveal the responsemechanism of G. bailinae to Cd2+ stress, providing valuable insights for assessing the bioremediation potential of G. bailinae for Cd-contaminated waters. [ABSTRACT FROM AUTHOR]

The toxic metal cadmium (Cd) poses a serious threat to plant growth and human health. Populus euphratica calcium-dependent protein kinase 21 (CPK21) has previously been shown to attenuate Cd toxicity by reducing Cd accumulation, enhancing antioxidant defense and improving water balance in transgenic Arabidopsis. Here, we confirmed a protein–protein interaction between PeCPK21 and Arabidopsis nuclear transcription factor YC3 (AtNF-YC3) by yeast two-hybrid and bimolecular fluorescence complementation assays. AtNF-YC3 was induced by Cd and strongly expressed in PeCPK21-overexpressed plants. Overexpression of AtNF-YC3 in Arabidopsis reduced the Cd inhibition of root length, fresh weight and membrane stability under Cd stress conditions (100 µM, 7 d), suggesting that AtNF-YC3 appears to contribute to the improvement of Cd stress tolerance. AtNF-YC3 improved Cd tolerance by limiting Cd uptake and accumulation, activating antioxidant enzymes and reducing hydrogen peroxide (H2O2) production under Cd stress. We conclude that PeCPK21 interacts with AtNF-YC3 to limit Cd accumulation and enhance the reactive oxygen species (ROS) scavenging system and thereby positively regulate plant adaptation to Cd environments. This study highlights the interaction between PeCPK21 and AtNF-YC3 under Cd stress conditions, which can be utilized to improve Cd tolerance in higher plants. [ABSTRACT FROM AUTHOR]

An unprecedented and direct PS‐MS (paper spray ionization mass spectrometry) method was proposed for the detection of native peptides, that is, glutathiones (GSHs), homoglutathiones (hGSHs), and phytochelatins (PCs), in basil (Ocimum basilicum L.) roots before and after cadmium exposure. The roots were submitted to cold maceration followed by sonication with formic acid as the extractor solvent for sample preparation. PS‐MS was used to analyze such extracts in the positive mode, and the results allowed for the detection of several GSHs, hGSHs, and PCs. Some of these PCs were not distinguished in the control samples, that is, basil roots not exposed to cadmium. Other PCs were noticed in both types of roots, uncontaminated and cadmium‐contaminated, but the intensities were higher in the former samples. Moreover, long‐time exposure to cadmium stimulated the formation of some of these PCs and their cadmium complexes. The results, therefore, provided some crucial insights into the defense mechanism of plants against an external stress condition due to exposure to a toxic heavy metal. The present study represents a promising alternative to investigate other crucial physiological processes in plants submitted to assorted stress conditions. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a pervasive environmental contaminant and a significant risk factor for liver injury. The present study was undertaken to evaluate the involvement of ferroptosis and neutrophil extracellular traps (NETs) in Cd‐induced liver injury in Nile tilapia (Oreochromis niloticus), and to explore its underlying mechanism. Cd‐induced liver injury was associated with increased total iron, malondialdehyde (MDA), and Acyl‐CoA synthetase long‐chain family member 4 (ACSL4), together with reduced levels of glutathione, glutathione peroxidase‐4a (Gpx4a), and solute carrier family 7 member 11 (SLC7A11), which are all hallmarks of ferroptosis. Moreover, liver hyperemia, neutrophil infiltration, increased inflammatory factors and myeloperoxidase, as well as elevated serum DNA content in Cd‐stimulated Nile tilapia suggested that a considerable number of neutrophils were recruited to the liver. Furtherly, in vitro experiments demonstrated that Cd induced the formation of NETs, and the possible mechanism was related to the generation of reactive oxygen species and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, along with the P38 and extracellular regulated protein kinase (ERK) signaling pathways. We concluded that ferroptosis and NETs are the critical mechanisms contributing to Cd‐induced liver injury in Nile tilapia. These findings will contribute to Cd toxicological studies in aquatic animals. [ABSTRACT FROM AUTHOR]

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This study investigates using magnesium foliar spray to enhance mint plants' growth and physiological performance under cadmium toxicity. It examines the effects of foliar application of magnesium oxide (40 mg L−1), in both nano and bulk forms, on mint plants exposed to cadmium stress (60 mg kg−1 soil). Cadmium stress reduced root growth and activity, plant biomass (32%), leaf hydration (19%), chlorophyll levels (27%), magnesium content (51%), and essential oil yield (35%), while increasing oxidative and osmotic stress in leaf tissues. Foliar application of magnesium increased root growth (32%), plant biomass, essential oil production (17%), leaf area (24%), chlorophyll content (10%), soluble sugar synthesis (33%), and antioxidant enzyme activity, and reduced lipid peroxidation and osmotic stress. Although the nano form of magnesium enhanced magnesium absorption, its impact on growth and physiological performance was not significantly different from the bulk form. Therefore, foliar application of both forms improves plants' ability to withstand cadmium toxicity. However, the study is limited by its focus on a single plant species and specific environmental conditions, which may affect the generalizability of the results. The long-term sustainability of such treatments could provide a more comprehensive understanding of magnesium's role in mitigating heavy metal stress in plants. [ABSTRACT FROM AUTHOR]

Rapid industrialization and urbanization have caused severe soil contamination with cadmium (Cd) necessitating effective remediation strategies. Phytoremediation is a widely adopted technology for remediating Cdcontaminated soil. Previous studies have shown that Abelmoschus manihot has a high Cd accumulation capacity and tolerance indicating its potential for Cd soil remediation. However, the mechanisms underlying its response to Cd stress remain unclear. In this study, physiological, transcriptomic, and metabolomic analyses were conducted to explore the response of A. manihot roots to Cd stress at different time points. The results revealed that Cd stress significantly increased malondialdehyde (MDA) levels in A. manihot, which simultaneously activated its antioxidant defense system, enhancing the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) by 19.73%-50%, 22.87%-38.89%, and 32.31%-45.40% at 12 h, 36 h, 72 h, and 7 days, respectively, compared with those in the control (CK). Moreover, transcriptomic and metabolomic analyses revealed 245, 5,708, 9,834, and 2,323 differentially expressed genes (DEGs), along with 66, 62, 156, and 90 differentially expressed metabolites (DEMs) at 12 h, 36 h, 72 h, and 7 days, respectively. Through weighted gene coexpression network analysis (WGCNA) of physiological indicators and transcript expression, eight hub genes involved in phenylpropanoid biosynthesis, signal transduction, and metal transport were identified. In addition, integrative analyses of metabolomic and transcriptomic data highlighted the activation of lipid metabolism and phenylpropanoid biosynthesis pathways under Cd stress suggesting that these pathways play crucial roles in the detoxification process and in enhancing Cd tolerance in A. manihot. This comprehensive study provides detailed insights into the response mechanisms of A. manihot to Cd toxicity. [ABSTRACT FROM AUTHOR]

In recent years, heavy metal pollution has become increasingly prominent, severely damaging ecosystems and biodiversity, and posing a serious threat to human health. However, the results of current methods for heavy metal restoration are not satisfactory, so it is urgent to find a new and effective method. Peptides are the units that make up proteins, with small molecular weights and strong biological activities. They can effectively repair proteins by forming complexes, reducing heavy metal ions, activating the plant's antioxidant defense system, and promoting the growth and metabolism of microorganisms. Peptides show great potential for the remediation of heavy metal contamination due to their special structure and properties. This paper reviews the research progress in recent years on the use of peptides to remediate heavy metal pollution, describes the mechanisms and applications of remediation, and provides references for the remediation of heavy metal pollution. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi can impact the host’s response to various environmental challenges, including lead (Pb) stress. Consequently, an investigation was set up to evaluate how the inoculation of Funneliformis mosseae (F.mosseae; FM) impacts the defense mechanisms in cotton plants subjected to Pb (1000 mg/kg) stress. The Pb treatment resulted in a substantial rise in Pb accumulation in both the roots and leaves. This led to elevated levels of methylglyoxal and hydrogen peroxide in the cotton leaves, accompanied by an increase in malondialdehyde content, ion leakage, and a reduction in photosynthetic pigments. The alterations were linked to a decline in photosynthetic performance and overall plant growth. Nevertheless, inoculation with the F. mosseae fungus resulted in the enhancement of photosynthetic pigment contents and the upregulation of Rubisco S and Rubisco L subunits, contributing to the protection of photosynthetic processes in stressed plants. Furthermore, this symbiotic fungus, through reducing Pb absorption and inducing increased activity of antioxidant and glyoxalase enzymes, led to the reduction of hydrogen peroxide and methylglyoxal levels while safeguarding membrane integrity under Pb stress. Plants inoculated with F. mosseae exhibited higher levels of metal-sequestering organic compounds, including glutathione and phytochelatins, in both roots and leaves, indicating their protective role in sequestering Pb from leaf tissues against Pb toxicity. This symbiosis also made photosynthetic organs more resistant to Pb toxicity by changing the metabolism of polyamines and making more spermidine and spermine levels in the leaves. Our research provides a theoretical foundation for the remediation of the symbiotic relationship between F. mosseae and cotton in environments contaminated with lead. [ABSTRACT FROM AUTHOR]

Lipoic acid (LA), a unique antioxidant compound, can stimulate the antioxidant defense system in plants subjected to abiotic stresses. We aimed to determine the role of LA in induction of the antioxidant system at lower reactive oxygen species (ROS), ascorbate (ASC) and glutathione (GSH) levels in osmotic-stressed maize (Zea mays L.). For this purpose, ROS, GSH and ASC contents were decreased using N,N'‑dimethylthiourea (DMTU), L-buthionine sulfoximine (BSO) and acriflavine (AF), respectively. Pots containing 21-day-old seedlings were divided into nine groups consisting of a non-stressed group; polyethylene glycol6000 (PEG)-induced osmotic stress (PEG) group, LA, DMTU, BSO and AF treatment groups; and DMTU, BSO, and AF-combined LA treatment groups under osmotic stress. ROS contents and membrane damage after the DMTU, BSO, and AF-combined LA treatments were lower than those after the DMTU, BSO, and AF treatments, respectively. Moreover, the LA treatments in combination with DMTU, BSO and AF increased dry weight, activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase, monodehydroascorbate reductase and dehydroascorbate reductase), and contents of GSH, ASC, and LA compared to the DMTU, BSO and AF treatments. Additionally, the relative expression levels of SUPEROXIDE DISMUTASE, CATALASE1 and ASCORBATE PEROXIDASE1 genes were consistent with the findings for their related antioxidant enzyme activities. These results indicated that LA could adjust ROS level and maintain stimulation of the antioxidant system at lower ROS, GSH, and ASC levels in osmotic stressed maize. Furthermore, LA may play a signaling role and assume the function of ASC and GSH in maize under PEG-induced osmotic stress. [ABSTRACT FROM AUTHOR]

The functional difference among the three copper-transporting P-type ATPases (CtpA, CtpB, and CtpV) annotated in genome of Mycobacterium tuberculosis (Mtb) remains unclear. Thus, CtpA and CtpB are believed to deliver copper to extracytoplasmic proteins as a cofactor required to overcome redox and copper stress in the Mtb periplasm. This study investigates an alternative role of CtpA-mediated copper transportation and its possible interaction with the activity of the multicopper oxidase, (MmcO), in response to redox stress. Results from RT-qPCR experiments indicate that the ctpA gene is upregulated in low Cu2+ concentrations, and under oxidative (H 2 O 2) and nitrosative (sodium nitroprusside) conditions in vitro, but not in high doses of Cu2+. Furthermore, the ctpA mutant strain (Mtb Δ ctpA) showed impaired growth in the presence of oxidative and nitrosative stress in vitro. However, it did not display such growth impairments in response to high doses of copper in comparison to the wild-type strain. Disruption of the ctpA gene in the Mtb genome did not induce an accumulation of copper in cells under toxic doses of the metal, suggesting that CtpA is not directly involved in copper detoxification. On the other hand, whole-cell lysates of the Mtb Δ ctpA mutant that were previously stimulated with Cu2+, H 2 O 2 and SNP (sodium nitroprusside), displayed reduced ability to oxidize organic substrates (para-phenylenediamine (pPD) and 2,2-azino-bis (3-ethylbenzothiazo-line-6-sulfonic acid) (ABTS). These finding strongly suggest that the efflux of copper transported by CtpA from the cytoplasm is relevant to the response to the redox stress and may be required for metalation and activity of MmcO in Mtb. [Display omitted] • CtpA is not directly required for copper detoxification in Mtb. • CtpA could deliver copper to the membrane cuproenzyme MmcO. • CtpA is required to overcome redox stress in Mtb cells. [ABSTRACT FROM AUTHOR]

We assessed the effect of non-protein thiols (NPSH), reduced glutathione (GSH) and n-acetylcysteine (NAC), on resin shear bond strength (SBS) to hydrogen peroxide (H2O2)-treated dentin, and their effects on the characteristics of dentin in comparison to ascorbic acid (AA) and sodium thiosulfate (STS). H2O2-treated dentin was conditioned with 5% AA, GSH, NAC, or STS applied for 1 or 5 min. The positive control group received H2O2 without antioxidant application, and the first negative control group received distilled water (DW). The specimens received resin bonding immediately after treatment except for the second negative control group (delayed bonding). Microhardness, roughness, and topography were studied. The SBS values of all antioxidants were statistically greater than the positive control group (p < 0.05); however, NAC and AA applied for 1 min demonstrated the highest values, which were comparable to delayed bonding. All treatments removed the smear layer except DW, H2O2, and STS. The negative effect of H2O2 on resin–dentin bonding was mitigated by the application of the antioxidants; however, their efficiencies were dependent on the antioxidant type and time of application. NAC was more effective in optimizing resin bonding to bleached dentin compared to GSH at 1 min application and STS at both application times but was comparable to AA. Negligible negative effects on the substrate's roughness and microhardness were detected. The antioxidant properties of the agent and its capacity to remove the smear layer are the processes underpinning the ability of a certain antioxidant to reverse the effect of H2O2 on bonding. [ABSTRACT FROM AUTHOR]

Metallothioneins are a class of proteins produced by both prokaryotes and eukaryotes, having low molecular weight and abundant cysteine residues. These proteins play a humongous role in binding, sequestration, and even buffering of the intracellular metal ions. Though they are a wide class of proteins, much of them are yet to be explored. Their metal binding attribute is unique and they form distinctive metal‐thiolate clusters. They have also been known to have ROS scavenging activities due to the presence of the cysteine residues. Phytochelatins also play major roles in metal sequestration pathways. Biofilms on the other hand are clusters of bacterial cells surrounded by an extracellular matrix of polymeric substances secreted by the bacteria themselves. Biofilms play multiple roles, from nutrient sequestration, stress resistance to surface adherence. But lesser explored arenas include assistance in heavy metal trapping and bio‐remediation. Researchers have conducted studies that have demonstrated increased metal trapping, resistance and uptake in biofilm forming strains than non‐biofilm forming mutants. Therefore, this study would explore the dual role of metallothionein and biofilm in their activity of metal sequestration and heavy metal remediation and provide certain insights so as to keenly understand the correlations between the two. [ABSTRACT FROM AUTHOR]

Stem cells in plants and animals are the source of new tissues and organs. In plants, stem cells are maintained in the central zone (CZ) of multicellular meristems, and large shoot meristems with an increased stem cell population hold promise for enhancing yield. The mobile homeodomain transcription factor WUSCHEL (WUS) is a central regulator of stem cell function in plant shoot meristems. Despite its central importance, the factors that directly modulate WUS protein stability have been a long-standing question. Here, we show that the peptidase DA1 physically interacts with and cleaves the WUS protein, leading to its destabilization. Furthermore, our results reveal that cytokinin signaling represses the level of DA1 protein in the shoot apical meristem, thereby increasing the accumulation of WUS protein. Consistent with these observations, loss of DA1 function results in larger shoot apical meristems with an increased stem cell population and also influences cytokinin-induced enlargement of shoot apical meristem. Collectively, our findings uncover a previously unrecognized mechanism by which the repression of DA1 by cytokinin signaling stabilizes WUS, resulting in the enlarged shoot apical meristems with the increased stem cell number during plant growth and development. The transcription factor WUSCHEL is essential for stem cell function, but factors that directly modulate WUS stability are unclear. This work discovers that the peptidase DA1 cleaves and destabilizes WUS to control shoot apical meristem size. [ABSTRACT FROM AUTHOR]

Hesperidin (HSP), a flavonoid, is a potent antioxidant, metal chelator, mediator of signaling pathways, and regulator of metal uptake in plants. The study examined the ameliorative effects of HSP (100 μM) on Bassia scoparia grown under excessive levels of heavy metals (zinc (500 mg kg−1), copper (400 mg kg−1), cadmium (100 mg kg−1), and chromium (100 mg kg−1)). The study clarifies the underlying mechanisms by which HSP lessens metabolic mayhem to enhance metal stress tolerance and phytoremediation efficiency of Bassia scoparia. Plants manifested diminished growth because of a drop in chlorophyll content and nutrient acquisition, along with exacerbated deterioration of cellular membranes reflected in elevated reactive oxygen species (ROS) production, lipid peroxidation, and relative membrane permeability. Besides the colossal production of cytotoxic methylglyoxal, the activity of lipoxygenase was also higher in plants under metal toxicity. Conversely, hesperidin suppressed the production of cytotoxic ROS and methylglyoxal. Hesperidin improved oxidative defense that protected membrane integrity. Hesperidin caused a more significant accumulation of osmolytes, non-protein thiols, and phytochelatins, thereby rendering metal ions non-toxic. Hydrogen sulfide and nitric oxide endogenous levels were intricately maintained higher in plants treated with HSP. Hesperidin increased metal accumulation in Bassia scoparia and thereby had the potential to promote the reclamation of metal-contaminated soils. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are small noncoding RNAs that play a vital role in plant responses to abiotic and biotic stresses. Recently, it has been discovered that some primary miRNAs (pri‐miRNAs) encode regulatory short peptides called miPEPs. However, the presence of miPEPs in rice, and their functions in response to abiotic stresses, particularly stress induced by heavy metals, remain poorly understood. Here, we identified a functional small peptide (miPEP156e) encoded by pri‐miR156e that regulates the expression of miR156 and its target SPL genes, thereby affecting miR156‐mediated cadmium (Cd) tolerance in rice. Overexpression of miPEP156e led to decreased uptake and accumulation of Cd and reactive oxygen species (ROS) levels in plants under Cd stress, resulting in improved rice Cd tolerance, as observed in miR156‐overexpressing lines. Conversely, miPEP156e mutants displayed sensitivity to Cd stress due to the elevated accumulation of Cd and ROS. Transcriptome analysis further revealed that miPEP156e improved rice Cd tolerance by modulating Cd transporter genes and ROS scavenging genes. Our study provides insights into the regulatory mechanism of miPEP156e in rice response to Cd stress and demonstrates the potential of miPEPs as an effective tool for improving crop abiotic stress tolerance. Summary statement: The 5' end of the pri‐miR156e contains a short open reading frame that encodes a small peptide called miPEP156e. This peptide plays a crucial role in regulating the activity of miR156 and has an impact on cadmium tolerance and accumulation by modulating cadmium uptake and maintaining redox homoeostasis in Oryza sativa. [ABSTRACT FROM AUTHOR]

The occurrence of internal browning in radish root is closely related to lipid peroxidation caused by excessive ROS production via NADPH-dependent ROS burst during the latter half of maturation. Japanese radish (Raphanus sativus L.) roots with differing severities of internal browning (IB) disorder grown under different soil temperatures were collected, and expression analysis of genes involved in NADPH-dependent ROS burst, mitochondrial electron transport chain, and ascorbate–glutathione cycle was performed. Roots with IB disorder were frequently found in higher soil temperature plots but rarely in the low soil temperature plot. Accumulation of metabolic products derived from the Maillard reaction and oxidative stress response was greater at higher soil temperatures. Although the content of hydrogen peroxide increased at higher soil temperatures, no clear correlation was found for sugar content among the experimental plots. Higher gene expressions related to NADPH-dependent ROS burst were detected at higher soil temperatures. Comparison of gene expression related to the mitochondrial electron transport chain in roots grown under different soil temperatures showed that the expression of complexes I- and III-related genes did not differ among the experimental plots. Furthermore, higher gene expressions related to the ascorbate–glutathione cycle were detected at higher soil temperatures. These facts indicate that the activation of NADPH-dependent oxidative burst induced by high temperatures increases lipid peroxidation, resulting in IB disorder in radish root. [ABSTRACT FROM AUTHOR]

Eriocheir sinensis, a key species in China's freshwater aquaculture, is threatened by various diseases, which were verified to be closely associated with oxidative stress. This study aimed to investigate the response of E. sinensis to hydrogen peroxide (H2O2)-induced oxidative stress to understand the biological processes behind these diseases. Crabs were exposed to different concentrations of H2O2 and their antioxidant enzyme activities and gene expressions for defense and immunity were measured. Results showed that activities of antioxidant enzymes—specificallysuperoxide dismutase (SOD), catalase (CAT), total antioxidant capacity(T-AOC), glutathione (GSH), and glutathione peroxidase (GSH-Px)—varied with exposure concentration and duration, initially increasing then decreasing. Notably, SOD, GSH-Px, and T-AOC activities dropped below control levels at 96 h. Concurrently, oxidative damage markers, including malondialdehyde (MDA), H2O2, and 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels, increased with exposure duration. The mRNA expression of SOD, CAT, and GSH-Px also showed an initial increase followed by a decrease, peaking at 72 h. The upregulation of phenoloxidaseloxidase (proPO) and peroxinectin (PX) was also detected, but proPO was suppressed under high levels of H2O2. Heat shock protein 70 (HSP70) expression gradually increased with higher H2O2 concentrations, whereas induced nitrogen monoxide synthase (iNOS) was upregulated but decreased at 96 h. These findings emphasize H2O2's significant impact on the crab's oxidative and immune responses, highlighting the importance of understanding cellular stress responses for disease prevention and therapy development. [ABSTRACT FROM AUTHOR]

This study aimed to assess the sorption capacity of a natural sorbent, specifically birch bark (BB), and its modification using chemical reagents, including nitric and hydrochloric acid, sodium hydroxide, and chloride. The objective of the chemical modification was to enhance the sorption capacity of the heavy metals cadmium(II), chromium(VI), and manganese(II). The most effective modification for adsorbing cadmium and manganese from aqueous solutions was achieved by treating the sorbent with a 0.1 M sodium hydroxide solution (BBNa). Conversely, in the case of chromium, each modification adversely affected its adsorption by the sorbent. Concentrations of the solutions were analyzed using atomic absorption spectrometry at appropriate time intervals. The adsorption process was described using Langmuir, Freundlich, and Temkin isotherms. The Freundlich isotherm provided the best fit for cadmium and chromium (R2 = 0.988 and 0.986, respectively), while the Langmuir isotherm was most suitable for manganese (R2 = 0.996). The sorption capacity varied for each metal ion: Cd (II)—33.13 mg/g, Cr (VI)—35.98 mg/g, and Mn (II)—24 mg/g for the highest concentration tested. This study employed pseudo–first-rate order, pseudo–second-rate order model kinetics, and the Weber–Morris model to examine the adsorption kinetics. The pseudo–second-rate order kinetics demonstrated the best fit (R2 > 0.94) for each heavy metal, which underlines the process's chemical nature. [ABSTRACT FROM AUTHOR]

In the face of flourishing industrialization and global trade, heavy metal and metalloid contamination of the environment is a growing concern throughout the world. The widespread presence of highly toxic compounds of arsenic, antimony, and cadmium in nature poses a particular threat to human health. Prolonged exposure to these toxins has been associated with severe human diseases, including cancer, diabetes, and neurodegenerative disorders. These toxins are known to induce analogous cellular stresses, such as DNA damage, disturbance of redox homeostasis, and proteotoxicity. To overcome these threats and improve or devise treatment methods, it is crucial to understand the mechanisms of cellular detoxification in metal and metalloid stress. Membrane proteins are key cellular components involved in the uptake, vacuolar/lysosomal sequestration, and efflux of these compounds; thus, deciphering the multilevel regulation of these proteins is of the utmost importance. In this review, we summarize data on the mechanisms of arsenic, antimony, and cadmium detoxification in the context of membrane proteome. We used yeast Saccharomyces cerevisiae as a eukaryotic model to elucidate the complex mechanisms of the production, regulation, and degradation of selected membrane transporters under metal(loid)-induced stress conditions. Additionally, we present data on orthologues membrane proteins involved in metal(loid)-associated diseases in humans. [ABSTRACT FROM AUTHOR]

Phytohormones, particularly cytokinin trans-zeatin (tZ), were studied for their impact on the green alga Desmodesmus armatus under cadmium (Cd) stress, focusing on growth, metal accumulation, and stress response mechanisms. Using atomic absorption spectroscopy for the Cd level and high-performance liquid chromatography for photosynthetic pigments and phytochelatins, along with spectrophotometry for antioxidants and liquid chromatography–mass spectrometry for phytohormones, we found that tZ enhances Cd uptake in D. armatus, potentially improving phycoremediation of aquatic environments. Cytokinin mitigates Cd toxicity by regulating internal phytohormone levels and activating metal tolerance pathways, increasing phytochelatin synthase activity and phytochelatin accumulation essential for Cd sequestration. Treatment with tZ and Cd also resulted in increased cell proliferation, photosynthetic pigment and antioxidant levels, and antioxidant enzyme activities, reducing oxidative stress. This suggests that cytokinin-mediated mechanisms in D. armatus enhance its capacity for Cd uptake and tolerance, offering promising avenues for more effective aquatic phycoremediation techniques. [ABSTRACT FROM AUTHOR]

Superoxide dismutase (SOD) protects plants from abiotic stress-induced reactive oxygen species (ROS) damage. Here, the effects of cadmium (Cd) exposure on ROS accumulation and SOD isozymes, as well as the identification of significant SOD isozyme genes, were investigated under different Cd stress treatments to Zhe-Maidong (Ophiopogon japonicus). The exposure to Cd stress resulted in a notable elevation in the SOD activity in roots. Cu/ZnSODa and Cu/ZnSODb were the most critical SOD isozymes in response to Cd stress, as indicated by the detection results for SOD isozymes. A total of 22 OjSOD genes were identified and classified into three subgroups, including 10 OjCu/ZnSODs, 6 OjMnSODs, and 6 OjFeSODs, based on the analysis of conserved motif and phylogenetic tree. Cu/ZnSOD-15, Cu/ZnSOD-18, Cu/ZnSOD-20, and Cu/ZnSOD-22 were the main genes that control the increase in SOD activity under Cd stress, as revealed via quantitative PCR and transcriptome analysis. Additionally, under various heavy metal stress (Cu2+, Fe2+, Zn2+, Mn2+), Cu/ZnSOD-15, Cu/ZnSOD-18, and Cu/ ZnSOD-22 gene expression were significantly upregulated, indicating that these three genes play a critical part in resisting heavy metal stress. The molecular docking experiments performed on the interaction between oxygen ion (O2•-) and OjSOD protein have revealed that the critical amino acid residues involved in the binding of Cu/ZnSOD-22 to the substrate were Pro135, Ile136, Ile140, and Arg144. Our findings provide a solid foundation for additional functional investigations on the OjSOD genes, as well as suggestions for improving genetic breeding and agricultural management strategies to increase Cd resistance in O. japonicus. [ABSTRACT FROM AUTHOR]

Chemical warfare agents (CWAs) refer to toxic chemical substances used in warfare. Recently, CWAs have been a critical threat for public safety due to their high toxicity. Metal–organic frameworks have exhibited great potential in protecting against CWAs due to their high crystallinity, stable structure, large specific surface area, high porosity, and adjustable structure. However, the metal clusters of most reported MOFs might be highly consumed when applied in CWA hydrolysis. Herein, we fabricated a two-dimensional piezoresponsive UiO-66-F4 and subjected it to CWA simulant dimethyl-4-nitrophenyl phosphate (DMNP) detoxification under sonic conditions. The results show that sonication can effectively enhance the removal performance under optimal conditions; the reaction rate constant k was upgraded 45% by sonication. Moreover, the first-principle calculation revealed that the band gap could be further widened with the application of mechanical stress, which was beneficial for the generation of 1O2, thus further upgrading the detoxification performance toward DMNP. This work demonstrated that mechanical vibration could be introduced to CWA protection, but promising applications are rarely reported. [ABSTRACT FROM AUTHOR]

Rice is prone to take up the toxic elements arsenic (As) and cadmium (Cd) from paddy soil through the transporters for other essential elements. Disruption of these essential transporters usually adversely affects the normal growth of rice and the homeostasis of essential elements. Here we report on developing low-As and low-Cd rice grain through the co-overexpression of OsPCS1 , OsABCC1 , and OsHMA3 genes under the control of the rice OsActin1 promoter. Co-overexpression of OsPCS1 and OsABCC1 synergistically decreased As concentration in the grain. Overexpression of OsPCS1 also decreased Cd concentration in the grain by restricting the xylem-to-phloem Cd transport in node I, but paradoxically caused Cd hypersensitivity as the overproduced phytochelatins in OsPCS1 -overexpressing plants suppressed OsHMA3-dependent Cd sequestration in vacuoles and promoted Cd transport from root to shoot. Co-overexpression of OsHAM3 and OsPCS1 overcame this suppression and complemented the Cd hypersensitivity. Compared with non-transgenic rice control, co-overexpression of OsABCC1 , OsPCS1 , and OsHMA3 in rice decreased As and Cd concentrations in grain by 92.1% and 98%, respectively, without causing any defect in plant growth and reproduction or of mineral nutrients in grain. Our research provides an effective approach and useful genetic materials for developing low-As and low-Cd rice grain. [ABSTRACT FROM AUTHOR]

Phytoremediation is a cost-effective and environmentally friendly method, offering a suitable alternative to chemical and physical approaches for the removal of pollutants from soil. This research explored the phytoremediation potential of Alhagi camelorum, a plant species, for total petroleum hydrocarbons (TPHs) and heavy metals (HMs), specifically lead (Pb), chromium (Cr), nickel (Ni), and cadmium (Cd), in oil-contaminated soil. A field-scale study spanning six months was conducted, involving the cultivation of A. camelorum seeds in a nursery and subsequent transplantation of seedlings onto prepared soil plots. Control plots, devoid of any plants, were also incorporated for comparison. Soil samples were analyzed throughout the study period using inductively coupled plasma-optical emission spectroscopy (ICP‒OES) for HMs and gas chromatography‒mass spectrometry (GC‒MS) for TPHs. The results showed that after six months, the average removal percentage was 53.6 ± 2.8% for TPHs and varying percentages observed for the HMs (Pb: 50 ± 2.1%, Cr: 47.6 ± 2.5%, Ni: 48.1 ± 1.6%, and Cd: 45.4 ± 3.5%). The upward trajectory in the population of heterotrophic bacteria and the level of microbial respiration, in contrast to the control plots, suggests that the presence of the plant plays a significant role in promoting soil microbial growth (P < 0.05). Moreover, kinetic rate models were examined to assess the rate of pollutant removal. The coefficient of determination consistently aligned with the first-order kinetic rate model for all the mentioned pollutants (R2 > 0.8). These results collectively suggest that phytoremediation employing A. camelorum can effectively reduce pollutants in oil-contaminated soils. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a toxic heavy metal element, which can cause oxidative stress in plant cells and induce cell damage. Currently, the research investigating autophagy function and Cd injury in plants is still limited. In our study, we exposed Pakchoi plants to Cd chloride at different concentrations (0, 2, 4, 6, and 8 mg·L−1) for 4 consecutive weeks. The results showed that toxic damage of Pakchoi was induced by Cd exposure and its Cd injury accumulation showed a positive dose relationship with metal concentrations. When Pakchoi was exposed to Cd, it generated excessive reactive oxygen species (ROS), especially H2O2. Our data revealed that LC3 upregulation and autophagosome formation were noted in H2O2-activated root cells, indicating that Cd damage caused autophagy in Pakchoi. Under Cd stress, the antioxidant enzyme activity of peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), and superoxide dismutase (SOD) were decreased as Cd concentration was increased, lowest in 8 mg·L−1 treatment. Using transcriptome analysis by RNA sequencing, we identified 860 significant differentially expressed genes (DEGs) with a fold change of no less than 2 between the Cd-treated and the control groups, among which 513 genes were upregulated and 347 genes were downregulated. The DEGs were mostly enriched in functions related to the hormonal regulation of digestion and absorption, transport processes, transporter activity, and the apical plasma membrane composition. A total of 6 autophagy-related genes, including 4 AMPK genes, 1 ATG13 gene, and 1 Beclin1 gene, were found to have significantly different expression levels in the Cd groups. The expression levels of these 6 genes were significantly different between the control and Cd groups (p < 0.05) when validated by real-time quantitative PCR. Furthermore, we found the ratio of p-AMPK and AMPK increased significantly in the Cd group (p < 0.05), indicating that Cd-induced autophagy may be mediated by AMPK phosphorylation. This research provides a better understanding of the stress effect of autophagy during Cd injury. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the role of Morganella morganii strains in alleviating Cd stress in Arabidopsis seedlings under controlled conditions. Both M. morganii strains ABT3 (ON316873) and ABT9 (ON316874) strains isolated from salt-affected areas showed higher resistance against Cd and possess plant growth-promoting traits such as nitrogen fixation, indole-acetic acid production, ammonia production, phosphate solubilization, and, catalase, gelatinase and protease enzyme production. Plant inoculation assay showed that varying concentration of Cd (1.5 mM and 2.5 mM) significantly reduced Arabidopsis growth, quantum yield (56.70%-66.49%), and chlorophyll content (31.90%-42.70%). Cd toxicity also triggered different associations between lipid peroxidation (43.61%-69.77%) and enzymatic antioxidant mechanisms. However, when both strains were applied to the Arabidopsis seedlings, the shoot and root length and fresh and dry weights were improved in the control and Cd-stressed plants. Moreover, both strains enhanced the resistance against Cd stress by increasing antioxidant enzyme activities [catalase (19.47%-27.39%) and peroxidase (37.50%-48.07%)]that ultimately cause a substantial reduction in lipid peroxidation (27.71%-41.90%). Both strains particularly ABT3 also showed positive results in improving quantum yield (73.84%-98.64%) and chlorophyll content (41.13%-48.63%), thus increasing the growth of Arabidopsis seedlings. The study suggests that PGPR can protect plants from Cd toxicity, and Cd-tolerant rhizobacterial strains can remediate heavy metal polluted sites and improve plant growth. In order to develop sustainable and effective agricultural techniques in areas polluted with heavy metals, it is important to have a deeper understanding of the characteristics of metal-resistant PGPR. Hence, this study focuses on the efficacy of M. morganii in promoting the growth and increasing the photosynthetic pigments of Arabidopsis seedlings under Cd toxicity. [ABSTRACT FROM AUTHOR]

Currently, there is an increasing presence of heavy metals and metalloids in soils and water due to anthropogenic activities. However, the biggest problem caused by this increase is the difficulty in recycling these elements and their high permanence in soils. There are plants with great capacity to assimilate these elements or make them less accessible to other organisms. We analyzed the behavior of Solanum lycopersicum L., a crop with great agronomic interest, under the stress caused by antimony (Sb). We evaluated the antioxidant response throughout different exposure times to the metalloid. Our results showed that the enzymes involved in the AsA-GSH cycle show changes in their expression level under the stress caused by Sb but could not find a relationship between the NITROSOGLUTATHIONE REDUCTASE (GSNOR) expression data and nitric oxide (NO) content in tomato roots exposed to Sb. We hypothesize that a better understanding of how these enzymes work could be key to develop more tolerant varieties to this kind of abiotic stress and could explain a greater or lesser phytoremediation capacity. Moreover, we deepened our knowledge about Glutathione S-transferase (GST) and Glutathione Reductase (GR) due to their involvement in the elimination of the xenobiotic component. [ABSTRACT FROM AUTHOR]

We report on the progress toward a dual-species cadmium and strontium atom interferometer for fundamental physics tests. We have developed and characterized a complete baseline laser system for cadmium, which provides the high power and narrow linewidth necessary for laser cooling and trapping and for performing atom interferometry, with upgraded systems for strontium also implemented. An overview of a design for cooling cadmium is presented, and we outline the basic design of a Cd–Sr atomic fountain, discussing atom launching techniques and the possible role of blackbody radiation. The excellent properties of cadmium and strontium, both individually and as a test pair, are discussed along with the enabled fundamental physics program of tests of the weak equivalence principle and the measurement of relativistic time dilation effects in quantum superpositions of clocks. [ABSTRACT FROM AUTHOR]

Intensive sulphur fertilisation has been reported to improve the nutrient balance and growth of Cd-exposed plants, but the reasons of this phenomenon and the role of sulphur compounds in the resistance to cadmium are unclear. We investigated sulphur supplementation-induced changes in the surface properties of roots and the level of thiol peptides (PCs) in Cd-stressed Triticum aestivum L. (monocots clade) and Lactuca sativa L. (dicots clade) grown in nutrient solution. The combination of three sulphur (2 mM S—basic level, 6 or 9 mM S—elevated levels) and four cadmium (0, 0.0002, 0.02 or 0.04 mM Cd) concentrations was used. The physicochemical parameters of the roots were determined based on the apparent surface area (Sr), total variable surface charge (Q), cation exchange capacity (CEC) and surface charge density (SCD). In Cd-exposed plants supplied with sulphur, a different character and trend in the physicochemical changes (adsorption and ion exchange) of roots were noted. At the increased sulphur levels, as a rule, the Sr, CEC, Q and SCD values clearly increased in the lettuce but decreased in the wheat in the entire range of the Cd concentrations, except the enhanced Sr of wheat supplied with 6 mM S together with elevated (0.0002 mM) and unchanged (0.02, 0.04 mM Cd) value of this parameter at 9 mM S. This indicates a clade-specific and/or species-specific plant reaction. The 6 mM S appears to be more effective than 9 mM S in alleviation of the cadmium's toxic effects on roots. It was found that at 0.02 and 0.04 mM Cd, the use of 6 mM S limits the Cd accumulation in the roots of both species in comparison with the basic S fertilisation. Moreover, PC accumulation was much more efficient in wheat than in lettuce, and intensive sulphur nutrition generally induced biosynthesis of these chelating compounds. Physicochemical parameters together with quantitative and qualitative assessment of thiol peptides can be important indicators of the efficiency of root system functioning under cadmium stress. The differences between the species and the multidirectional character of the changes are a result of the involvement of a number of multi-level mechanisms engaged in the defence against metal toxicity. [ABSTRACT FROM AUTHOR]

Introduction: Cadmium (Cd) is a highly toxic heavy metal which contaminates agricultural soils and is easily absorbed by plants. Brassica rapa L. is one of the most popular vegetables in China and is known to accumulate Cd in its roots and aerial tissues. Methods: A highly Cd-resistant bacterium (‘CD2’) was isolated and identified. Its ability to immobilize Cd(II) in medium was studied. Strain CD2 were added into Cd-polluted soil to ameliorate Cd accumulation in B. rapa. The underlying mechanisms of ‘CD2’ to reduce Cd accumulation in B. rapa. were analyzed by transcriptomics. Results and discussion: Strain CD2 was classified as belonging to the genus Stenotrophomonas. Strain CD2 was found to be able to remove 0.1 mmol/L Cd(II) after 36 h by intracellular sequestration and by producing biofilm, exopolysaccharide, and H2S. When applied to Cd-contaminated soil, ‘CD2’ significantly increased the content of nonbioavailable Cd by 212.70%. Furthermore, ‘CD2’-inoculated B. rapa exhibited a 51.16% decrease in the Cd content of roots and a 55.56% decrease in the Cd content of aerial tissues. Transcriptome analysis identified 424 differentially expressed genes (DEGs) in the roots and 501 DEGs in the aerial tissues of uninoculated Cd-exposed plants. By comparison, 1107 DEGs were identified in the roots and 1721 DEGs were identified in the aerial tissues of ‘CD2’-inoculated Cd-exposed plants. In both treatment groups, genes related to vacuolar sequestration were upregulated, resulting in inhibited Cd transport. In addition, both catalase and glutathione transferase were induced in uninoculated plants, while the oxidative stressrelated genes CPK and RBOH belonged to ‘plant-pathogen interactions’ were upregulated in ‘CD2’-inoculated plants. Moreover, inoculation with ‘CD2’ resulted in the enrichment of phenylpropane metabolism; cutin, suberine, and wax biosynthesis; and the AP2, Dof, WOX, Trihelix, B3, EIL, and M-type_MADS transcription factors; as well as the downregulation of zinc transporters and blue copper proteins. All of these changes likely contributed to the reduced Cd accumulation in ‘CD2’-inoculated B. rapa. The results of this study suggest that Stenotrophomonas sp. CD2 may prove to be a useful inoculant to prevent Cd accumulation in B. rapa. [ABSTRACT FROM AUTHOR]

Early-life respiratory syncytial virus (RSV) infection (eRSV) is one of the leading causes of serious pulmonary disease in children. eRSV is associated with higher risk of developing asthma and compromised lung function later in life. Cadmium (Cd) is a toxic metal, widely present in the environment and in food. We recently showed that eRSV reprograms metabolism and potentiates Cd toxicity in the lung, and our transcriptome-metabolome-wide study showed strong associations between S-palmitoyl transferase expression and Cd-stimulated lung inflammation and fibrosis signaling. Limited information is available on the mechanism by which eRSV reprograms metabolism and potentiates Cd toxicity in the lung. In the current study, we used a mouse model to examine the role of protein S-palmitoylation (Pr-S-Pal) in low dose Cd-elevated lung metabolic disruption and inflammation following eRSV. Mice exposed to eRSV were later treated with Cd (3.3 mg CdCl2/l) in drinking water for 6 weeks (RSV + Cd). The role of Pr-S-Pal was studied using a palmitoyl transferase inhibitor, 2-bromopalmitate (BP, 10 µM). Inflammatory marker analysis showed that cytokines, chemokines, and inflammatory cells were highest in the RSV + Cd group, and BP decreased inflammatory markers. Lung metabolomics analysis showed that pathways including phenylalanine, tyrosine and tryptophan, phosphatidylinositol and sphingolipid were altered across treatments. The BP antagonized metabolic disruption of sphingolipid and glycosaminoglycan metabolism by RSV + Cd, consistent with BP effect on inflammatory markers. This study shows that Cd exposure following eRSV has a significant impact on subsequent inflammatory response and lung metabolism, which is mediated by Pr-S-Pal, and warrants future research for a therapeutic target. [ABSTRACT FROM AUTHOR]

Starry flounders (Platichthys stellatus) (average weight—114.69 ± 13 g, length—19.0 ± 0.21 cm) underwent a 4-week exposure to varying dietary cadmium (Cd) concentrations: 0, 10, 20, 40, 60, and 80 mg/kg. Bioaccumulation patterns were revealed in the intestine, kidney, liver, and gills in descending order of accumulation. Significant declines in growth indicators—body weight gain (BWG), specific growth rate (SGR), and feed efficiency ratio percentage (FER)—were evident at 80 mg Cd/kg for 2 weeks and beyond 60 mg Cd/kg for 4 weeks. Hematological parameters, including red blood cell (RBC) count, hematocrit (Ht), and hemoglobin (Hb), remarkably reduced at 80 mg Cd/kg for both 2 and 4 weeks. The total plasma protein reduced significantly after exposure to Cd for 2 and 4 weeks, alongside increased glucose levels, glutamic oxaloacetic transaminase (GOT), and glutamic pyruvate transaminase (GPT). Considerable increases in antioxidant responses—superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), and glutathione (GSH) levels—were observed after exposure to Cd for 2 and 4 weeks. P. stellatus exhibits a high accumulation of dietary Cd in specific tissues. Moreover, concentrations above 60 mg Cd/kg adversely affected the growth performance, hematological parameters, plasma components, and antioxidant responses. [ABSTRACT FROM AUTHOR]

• Cadmium (Cd) toxicity caused oxidative stress and lipid peroxidation in tomato seedlings. • Under Cd stress, the activity of mitochondrial ATP synthase was downregulated. • S-nitrosoglutathione (GSNO) proved helpful in improving the activity of ATP synthase and the activation level of defense mechanisms. • GSNO provided protection to the plants against Cd stress. • The positive effect of GSNO was dependent on endogenous levels of hydrogen sulfide. The contamination of soils with cadmium (Cd) threatens agricultural productivity worldwide. The ability of plants to withstand challenging circumstances is primarily contingent upon their inherent capacity for tolerance and defense. The purpose of the current work is to gain a better understanding of how the mitochondrial ATP synthase enzyme, the antioxidant defense system, redox homeostasis, and chlorophyll metabolism in tomato seedlings are regulated by nitric oxide and hydrogen sulfide under Cd stress. The results demonstrate that exposure of tomato seedlings to Cd stress resulted in a substantial decrease in the activity of ATP synthase. The plants exposed to Cd stress, exhibited an increase in chlorophyllase activity and a substantial decrease in the activity of δ-aminolevulinic acid dehydratase, which resulted in a substantial loss of chlorophyll content. Elevation in the antioxidant defense system under Cd stress could not bring a significant positive change in the plants' defense system that resulted in lipid peroxidation and leakage of electrolytes. Incubation of Cd-stressed seedlings with nitric oxide donor S-nitrosoglutathione (GSNO) proved remarkable in improving the performance of the plants. The results exhibit that GSNO application improved the activity of ATP synthase, superoxide dismutase, peroxidase, and catalase and the performance of the ascorbate-glutathione system, which efficiently scavenged excess reactive oxygen species. The positive effect of GSNO application was also shown by decreased lipid peroxidation and electrolyte leakage. However, application of DL-propargylglycine (a biosynthesis inhibitor of hydrogen sulfide) to the stressed-seedlings reversed the effect of GSNO, which resulted in the weak performance of the defense system and the commencement of oxidative stress. The results of the study substantiate that nitric oxide, in association with endogenous hydrogen sulfide, was remarkable in providing protection to the plants against Cd toxicity. [ABSTRACT FROM AUTHOR]

Background and Aims: The role of L-histidine (L-His) in nickel (Ni) hyperaccumulation is not well known. The present study aimed to understand the impact of L-His on Ni translocation and Ni tolerance in Odontarrhena inflata and Aurinia saxatilis. Methods: To determine the impact of L-His and L-alanine (L-Ala) on the shoot Ni accumulation, we quantified the Ni concentration in plants pretreated with amino acids for 4 h and then exposed to Ni for 8 h. Hydrogen peroxide (H2O2) and antioxidant enzymes activities were determined after 4 h of pretreatments and 48 h of Ni treatments. Results: L-histidine increased Ni translocation to shoots in O. inflata and A. saxatilis. Ni increased the activity of POD, APX, and CAT in both species, but the activities of APX and CAT were higher in O. inflata. Ni exposure increased the H2O2 concentration in A. saxatilis. L-His pretreatment did not decrease the H2O2 concentration in Ni-treated plants, but decreased the activity of POD, APX, and CAT only at 300 µM Ni in O. inflata. In A. saxatilis, L-His pretreatment, decreased the activity of CAT, but increased POD activity at 150 and 300 µM Ni. Pretreatment with L-Ala decreased POD and APX activity but had no significant impact on H2O2 concentration and CAT activity. Conclusion: L-Histidine promoted root-to-shoot Ni translocation and alleviated Ni toxicity, possibly through inducing the activities of antioxidant enzymes, in hyperaccumulator and non-accumulator plants. Histidine might not only facilitate the Ni translocation, but also contribute to Ni tolerance, at least in A. saxatlilis. [ABSTRACT FROM AUTHOR]