ZnO Nanoparticles Treatment Research Articles

ZnO nanoparticles enhances cadmium tolerance by modulating N6-methyladenosine (m6A) level of stress-responsive genes NRT1 and GM35E in vegetable soybean

Cadmium (Cd) is a hazardous heavy metal pollutant that poses significant risks to agricultural production and human health. Nanoparticles (NPs) can alleviate the effects of cadmium on crops by regulating the expression of stress-responsive genes, however, the mechanism of regulation is unknown. N6-methyladenosine (m6A) is a prevalent RNA modification, which determines the expression level of RNA. In this study, we performed m6A methylome analysis and gene editing to investigate the regulation of stress-responsive genes by m6A under Cd stress with ZnO nanoparticles (ZnO NPs). Firstly, we identified 16 differentially expressed genes (DEGs) with differential m6A-modification by m6A methylome seq, which included 6 stress-responsive genes. ZnO NPs treatment reduced the m6A level and stabilized the mRNAs of these stress-responsive genes. Then, we utilized the in vivo m6A modification tool, Plant m6A Editors (PMEs), specifically reduced the m6A level of NRT1 and GM35E in transgenic plants. The expression of NRT1 and GM35E was increased, and plants carrying PMEs-NRT1 and PMEs-GM35E showed stronger Cd tolerance than control. Therefore, we can conclude that NPs enhance Cd tolerance in plants by regulating the m6A methylation level of stress-responsive genes such as NRT1 and GM35E, which ultimately affects the expression of these genes. This study proposed a post-transcriptional regulatory network in vegetable soybean roots responding to Cd with ZnO NPs, potentially offering new insights into gene manipulation for controlling low Cd accumulation in crops.

Impact of ZnO nanopriming on physiological and biochemical traits of wheat (Triticum aestivum L.) seedling

To ascertain the ideal dosage of ZnO NPs (Zinc Oxide Nanoparticles), we conducted an investigation on the priming effects of varying concentrations of ZnO NPs on germination and physio-biochemical parameters of wheat. In this study, ZnO NPs were synthesized and characterized for their physico-chemical properties followed by confirmation of the formation of ZnO NPs. Throughout this study, wheat seeds were subjected to ZnO NPs at various concentrations of 5, 50, 100, 250, and 500 ppm for a period of 4 h via continuous aeration. The primed seeds were sowed in plastic bags, allowed to grow for 21 days, following which comprehensive evaluations of physio-biochemical attributes were conducted. At 250 ppm, an impressive 100% of seeds successfully germinated compared to the control group. The examined physiological factors such as shoot length, root length, and fresh as well as dry weights of leaf and root tissues all exhibited notable increases with the ascending concentrations of ZnO NP up to 250 ppm. However, beyond this threshold, at 500 ppm, these parameters experienced a decline. Inductively coupled plasma atomic absorption spectrophotometer (ICP-AAS) measurements validated the progressive increase in Zinc content in the nanoprimed seedlings, further affirming the dose-dependent trend. Zinc oxide nanoparticles notably improved key biochemical features, including elevated levels of total chlorophyll, malondialdehyde (MDA), total protein, and the accumulation of osmolytes such as proline and glycine-betaine. Additionally, the presence of ZnO NPs led to increased activity of antioxidant enzymes like superoxide dismutase (SOD) and catalase in a dose-dependent mananer. Collectively, the amassed data underscores the efficacy of the 250 ppm ZnO NPs treatment, which emerged as superior in comparison to both the control group and other administered treatments. These findings underscore the potential of ZnO NPs at a concentration of 250 ppm as a valuable seed nanopriming agent, effectively enhanced germination and robust early-stage growth in young plants.

Impacts of ZnO nanoparticles and dissolved zinc (ZnSO4) on low temperature induced responses of wheat

Nanoparticles (NPs), due to their specific physical and chemical properties, can cause benefits and risks once they are released into the environment. Consideration of nano-specific impacts of nanomaterials is essential for the safe design of NPs applications. In the present study, the effects of ZnO NPs and ZnSO4 application on low temperature-induced responses was investigated in two wheat cultivars (Triticum aestivum L. spring cultivar Sivand and the winter cultivar Pishgam). Seedlings were grown in a Johnson nutrient solution and then exposed to the uptake solution containing zinc (Zn) from two sources of ZnSO4 and ZnO NPs and subjected to temperature treatments by incubating them in the dark at +25, +9, and −4 °C for 18 h. Our results indicate that ZnO NPs and ZnSO4 did not show the same effects on wheat cultivars at freezing temperature. The ZnO NPs led to an increase in malondialdehyde (MDA) content, higher electrolyte leakage, and intensified the freezing effects compared to ZnSO4 and Zn-free treatments, in Sivand. At optimum temperature, root MDA content and electrolyte leakage index (ELI) was greater in Sivand plants compared to Pishgam. The differences indicate that the two cultivars differ in their responses to ZnO NPs application and low temperatures. In general, Sivand reacted more sensitively to the ZnO NPs treatment compared to ZnSO4. Freezing temperature resulted in higher activity of superoxide dismutase (SOD), MDA content and ELI in both wheat cultivars. In Sivand, with regard to the activity of SOD, MDA content and ELI, ZnO NPs cause effects different from that of ZnSO4, which indicates that ZnO NPs used under the current experimental conditions because nano-specific risks under low temperatures.

Effect of zinc nanoparticles on the growth and biofortification capability of mungbean (Vigna radiata) seedlings.

The online version contains supplementary material available at 10.1007/s11756-022-01269-3.

The Combined Analysis of Transcriptome and Antioxidant Enzymes Revealed the Mechanism of EBL and ZnO NPs Enhancing Styrax tonkinensis Seed Abiotic Stress Resistance.

As global climate change worsens, trees will have difficulties adapting to abiotic pressures, particularly in the field, where environmental characteristics are difficult to control. A prospective commercial and ornamental tree species, Styrax tonkinensis, has its seed oil output and quality reduced as a result, which lowers the economic benefits. This necessitates growers to implement efficient strategies to increase the seeds of woody biofuel species' tolerance to abiotic stress. Numerous studies have shown that ZnO nanoparticles (NPs), a new material, and BRs assist plants to increase their resilience to abiotic stress and subsequently adapt to it. However, there have not been many investigations into S. tonkinensis seed resistance. In this study, we examined the changes in antioxidant enzyme activities and transcriptomic results of S. tonkinensis seeds throughout the seed development period to investigate the effects of 24-epibrassinolide (EBL), one of the BRs, and ZnO NPs treatments alone or together on the stress resistance of S. tonkinensis seeds. On 70, 100, and 130 days after flowering (DAF), spraying EBL or ZnO NPs increased the activity of antioxidant enzymes (POD, SOD, and CAT) in S. tonkinensis seeds. Moreover, when the EBL and ZnO NPs were sprayed together, the activities of antioxidant enzymes were the strongest, which suggests that the positive effects of the two can be superimposed. On 70 and 100 DAF, the EBL and ZnO NPs treatments improved seed stress resistance, mostly through complex plant hormone crosstalk signaling, which includes IAA, JA, BR, and ABA signaling. Additionally, ABA played an essential role in hormone crosstalk, while, on 130 DAF, due to the physiological characteristics of seeds themselves in the late stage of maturity, the improvement in seed stress resistance by EBL and ZnO NPs was related to protein synthesis, especially late embryogenesis-abundant protein (LEA), and other nutrient storage in seeds. Spraying EBL and ZnO NPs during the seed growth of S. tonkinensis could significantly increase seed stress resistance. Our findings provide fresh perspectives on how cultural practices can increase abiotic stress tolerance in woody seedlings.

Effects of TiO2 and ZnO nanoparticles on the growth of phytoplankton assemblages in seawater

Compounds in sunscreen such as ultraviolet (UV) filters protect human skin from damage caused by UV radiation exposure. However, sunscreen components reach marine ecosystems after their release from human skin during activities such as swimming and washing, and are potentially toxic to marine organisms. TiO2 and ZnO nanoparticles (NPs) are commonly used as inorganic UV filters. In this study, we explored the effects of TiO2 and ZnO NPs on natural phytoplankton assemblages in coastal seawater. Growth rates of natural phytoplankton assemblages were significantly decreased by 10 mg L−1 TiO2 and 1 and 10 mg L−1 ZnO NP treatments. NP addition also modified the size structure of phytoplankton assemblages, and small phytoplankton (mainly cyanobacteria) are vulnerable to NPs. Because herbivore food preferences depend strongly on algal cell size, NP contamination could also affect higher trophic levels. Notably, small phytoplankton are an important component in microbial loop, and this energy transfer pathway may be more vulnerable to NP contamination.

ZnO Nanoparticle Size-Dependent Effects on Swiss Chard Growth and Nutritional Quality

Understanding the interactions between nanoparticles (NPs) and plants is crucial in comprehending the impact of nanotechnology on agriculture, with a focus on plant toxicity concerns and risks to human health. Zinc (Zn) belongs to the micronutrients with poor bioavailability, though this element is essential for the vital functions of plants. In this respect, this research estimated the impact of the size of zinc oxide NPs (ZnO NPs) applied by foliar application on biomass production and nutritional qualities in baby leaf Swiss chard (Beta vulgaris ssp. cicla L. cv. Barese). Plants were grown hydroponically in controlled environment growth chambers, and exposed via foliar spray to varying particle sizes of ZnO NPs (18, 35–45, and 80–200 nm) at a concentration of 200 ppm. Control plants were sprayed with distilled water. The results revealed that ZnO NPs improved fresh and dry biomass, leaf area, favored leaf chlorophyll and flavonol indexes, and improved the total soluble protein content in Swiss chard. The total phenolic content and antioxidant properties depended more on different sizes of ZnO NPs in the solutions used for spraying plants. ZnO NPs significantly increased the accumulation of Zn and Fe in edible tissues. Still, the hazard quotient values of Zn and Fe were lower than 1, which supports the safe consumption of Swiss chard after ZnO NP treatment. In conclusion, these results revealed that ZnO NPs could be applied in Swiss chard production to improve yield, quality, and nutraceutical properties.

Phytoremediation of nanoparticle-contaminated soil using the halophyte plant species Suaeda glauca

Although concerns about the exposure of natural ecosystems to nanomaterials are increasing, research on how to remove toxic substances from the ecosystem is lacking. In this study, we investigated the phytoremediation ability of Suaeda glauca , a salt marsh plant, to remove nanomaterials introduced into the coastal ecosystem through the sewage system. TiO 2 nanoparticles (NPs) and ZnO NPs, which are commonly used in agriculture, cosmetics and industry are used for test materials. In comparison with the land plant Brassica campestris , which has been extensively used for heavy metal remediation, S. glauca was more resistant to nanomaterials and showed higher nanoparticle uptake. The Zn content of S. glauca plants was significantly higher than that of B. campestris plants in the 100 mg/kg ZnO NP treatment, and only S. glauca has survived 1000 mg/kg ZnO NP treatment. Furthermore, Ti contents of S. glauca plants was significantly higher than that of B. campestris plants in the 100 mg/kg TiO 2 NP treatment. Additionally, S. glauca showed higher dry weight than B. campestris in every treatments after exposure to nanomaterials, indicating better total remediation capacity. Our results suggest that S. glauca , and potentially other salt marsh plants, can be effectively used to remove nanoparticles from coastal ecosystems. • S. glauca showed strong resistance to the high concentration of NPs. • S. glauca showed higher NP absorption than the terrestrial plant B. campestris. • The excellent soil purification ability of individual halophytes for NPs was confirmed. • NPs can be effectively removed through phytoremediation using halophytes.

Effect of ZnO and CuO nanoparticles on the growth, nutrient absorption, and potential health risk of the seasonal vegetable Medicago polymorpha L.

BackgroundMedicago polymorpha L., a seasonal vegetable, is commonly grown in China. The increasing use of nanoparticles (NPs) such as ZnO and CuO NPs in agriculture has raised concerns about their potential risks for plant growth and for human consumption. There is a lack of research on the effects of ZnO and CuO NPs on agronomic performance of Medicago polymorpha L. and their potential risks for human health.MethodsIn this study, different treatment concentrations of ZnO NPs (25, 50, 100, and 200 mg kg−1) and CuO NPs (10, 25, 50, and 100 mg kg−1) were used to determine their effects on the growth and nutrient absorption of Medicago polymorpha L., as well as their potential risk for human health.ResultsThe results showed that ZnO and CuO NPs increased the fresh weight of Medicago polymorpha L. by 5.8–11.8 and 3.7–8.1%, respectively. The best performance for ZnO NPs occurred between 25–50 mg kg−1 and the best performance for CuO NPs occurred between 10–25 mg kg−1. Compared with the control, ZnO and CuO NPs improved the macronutrients phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca). The following micronutrients were also improved: iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), and manganese (Mn), with the exception of nitrogen (N) accumulation. Low treatment concentrations exhibited more efficient nutrient uptake than high treatment concentrations. A comprehensive analysis showed that the optimum concentrations were 25 mg kg−1 for ZnO NPs and 10 mg kg−1 for CuO NPs. The potential non-carcinogenic health risk of Medicago polymorpha L. treated with ZnO and CuO NPs was analyzed according to the estimated daily intake (EDI), the hazard quotient (HQ), and the cumulative hazard quotient (CHQ). Compared with the oral reference dose, the EDI under different ZnO and CuO NPs treatments was lower. The HQ and CHQ under different ZnO and CuO NPs treatments were far below 1. This indicated that Medicago polymorpha L. treated with ZnO and CuO NPs did not pose any non-carcinogenic health risk to the human body. Therefore, ZnO and CuO NPs were considered as a safe nano fertilizer for Medicago polymorpha L. production according to growth analysis and a human health risk assessment.

Effects of Zinc, Copper and Iron Oxide Nanoparticles on Induced DNA Methylation, Genomic Instability and LTR Retrotransposon Polymorphism in Wheat (Triticum aestivum L.).

Nanomaterials with unique and diverse physico-chemical properties are used in plant science since they improve plant growth and development and offer protection against biotic and abiotic stressors. Previous studies have explored the effects of such nanomaterials on different plant mechanisms, but information about the effects of nanomaterials on induced DNA methylation, genomic instability and LTR retrotransposon polymorphism in wheat is lacking. Therefore, the present study highlights the key role of nanoparticles in DNA methylation and polymorphism in wheat by investigating the effects of ZnO, CuO and γ-Fe3O4 nanoparticles (NPs) on mature embryo cultures of wheat (Triticum aestivum L.). Nanoparticles were supplemented with Murashige and Skoog (MS) basal medium at normal (1X), double (2X) and triple (3X) concentrations. The findings revealed different responses to the polymorphism rate depending on the nanoparticle type and concentration. Genomic template stability (GTS) values were used to compare the changes encountered in iPBS profiles. ZnO, CuO and γ-Fe3O4 NPs increased the polymorphism rate and cytosine methylation compared to the positive control while reducing GTS values. Moreover, non-γ-Fe3O4 NPs treatments and 2X ZnO and CuO NP treatments yielded higher polymorphism percentages in both MspI- and HpaII-digested CRED-iPBS assays and were thus classified as hypermethylation when the average polymorphism percentage for MspI digestion was considered. On the other hand, the 3X concentrations of all nanoparticles decreased HpaII and MspI polymorphism percentages and were thus classified as hypomethylation. The findings revealed that MS medium supplemented with nanoparticles had epigenetic and genotoxic effects.

CeO2-Zn Nanocomposite Induced Superoxide, Autophagy and a Non-Apoptotic Mode of Cell Death in Human Umbilical-Vein-Derived Endothelial (HUVE) Cells.

In this study, a nanocomposite of cerium oxide-zinc (CeO2-Zn; 26 ± 11 nm) based on the antioxidant rare-earth cerium oxide (CeO2) nanoparticles (NPs) with the modifier zinc (Zn) was synthesized by sintering method and characterized. Its bio-response was examined in human umbilical-vein-derived endothelial (HUVE) cells to get insight into the components of vascular system. While NPs of CeO2 did not significantly alter cell viability up to a concentration of 200 µg/mL for a 24 h exposure, 154 ± 6 µg/mL of nanocomposite CeO2-Zn induced 50% cytotoxicity. Mechanism of cytotoxicity occurring due to nanocomposite by its Zn content was compared by choosing NPs of ZnO, possibly the closest nanoparticulate form of Zn. ZnO NPs lead to the induction of higher reactive oxygen species (ROS) (DCF-fluorescence), steeper depletion in antioxidant glutathione (GSH) and a greater loss of mitochondrial membrane potential (MMP) as compared to that induced by CeO2-Zn nanocomposite. Nanocomposite of CeO2-Zn, on the other hand, lead to significant higher induction of superoxide radical (O2•−, DHE fluorescence), nitric oxide (NO, determined by DAR-2 imaging and Griess reagent) and autophagic vesicles (determined by Lysotracker and monodansylcadeverine probes) as compared to that caused by ZnO NP treatment. Moreover, analysis after triple staining (by annexin V-FITC, PI, and Hoechst) conducted at their respective IC50s revealed an apoptosis mode of cell death due to ZnO NPs, whereas CeO2-Zn nanocomposite induced a mechanism of cell death that was significantly different from apoptosis. Our findings on advanced biomarkers such as autophagy and mode of cell death suggested the CeO2-Zn nanocomposite might behave as independent nanostructure from its constituent ones. Since nanocomposites can behave independently of their constituent NPs/elements, by creating nanocomposites, NP versatility can be increased manifold by just manipulating existing NPs. Moreover, data in this study can furnish early mechanistic insight about the potential damage that could occur in the integrity of vascular systems.

ZnO nanoparticle-based seed priming modulates early growth and enhances physio-biochemical and metabolic profiles of fragrant rice against cadmium toxicity

BackgroundCadmium (Cd) is amongst the most toxic heavy metals that severely affects crop growth, whereas application of nanoparticles (NPs) to negate the toxic effects of heavy metals could be an effective management approach. In the present study, the seeds of two fragrant rice varieties i.e., Yuxiangyouzhan and Xiangyaxiangzhan under normal and Cd stress conditions i.e., 0 and 100 mg L− 1 applied with four levels of ZnO NPs i.e., 0, 25, 50, and 100 mg L− 1.ResultsSeed priming with ZnO NPs had no significant effect on the seed germination (p > 0.05) however, it substantially improved the seedling growth and other related physiological attributes under the Cd stress. The mean fresh weight of the shoot, and whole seedling was increased by 16.92–27.88% and by 16.92–27.88% after ZnO NPs application. The root fresh weight, root-shoot length was also substantially improved under ZnO NPs treatment. Moreover, application of ZnO NPs induced modulations in physiological and biochemical attributes e.g., the superoxide dismutase (SOD) activity in root and shoot, the peroxidase (POD) activity and metallothionein contents in root were increased under low levels of ZnO NPs. The α-amylase and total amylase activity were improved by ZnO NPs application under Cd Stress. Besides, modulation in Zn concentration and ZnO NPs uptake in the seedling were detected. The metabolomic analysis indicated that various pathways such as alanine, aspartate and glutamate metabolism, phenylpropanoid biosynthesis, and taurine and hypotaurine metabolism were possibly important for rice response to ZnO NPs and Cd.ConclusionOverall, application of ZnO NPs substantially improved the early growth and related physio-biochemical attributes in rice. Our findings provide new insights regarding the effects of ZnO NPs on seed germination, and early growth of rice, and its potential applications in developing crop resilience against Cd contaminated soils.

Impacts of zinc oxide nano and bulk particles on redox-enzymes of the Punica granatum callus

The structure and function of cellular membranes were sustained by redox-enzymes. We studied the interaction between the oxidative stress caused by excessive accumulation of ZnO-nanoparticles (ZnO-NPs) in plants and the role of redox-enzymes that can alleviate this stress. The crude callus extract from pomegranate, which was treated with 0, 10, and 150 µg mL−1 ZnO-NPs or bulk particles (ZnO-BPs), was applied to study the activity and kinetics of redox-enzymes. The elevated ZnO-NPs, enhanced the lipoxygenase and polyphenol oxidase activity, while the ZnO-BPs did not modify them. The activities of superoxide dismutase, catalase, and phenylalanine ammonia-lyase were induced under ZnO-NPs or BPs treatments, whilst the opposite trend of peroxidase was observed. Ascorbate peroxidase activity increased under ZnO-NPs treatments but decreased under ZnO-BPs. The kinetics activity of enzymes showed changes under different levels of NPs and BPs. Additionally, NPs or BPs treatments reduced the uptake of copper, iron, magnesium, but increased zinc accumulation in callus tissues. Meanwhile, these treatments enhanced the accumulation of manganese ions but did not affect the accumulation of potassium and phosphorous in ZnO-NPs or BPs-stressed calli. Collectively, these results gave a quantitative evaluation of the competition of zinc and other minerals on the carriers, and in addition, they provided a basis for how to control ZnO-NPs or BPs toxicity via redox-enzymes.

CuO and ZnO Nanoparticle Application in Synthetic Soil Modulates Morphology, Nutritional Contents, and Metal Analysis of Brassica nigra.

Black mustard (Brassica nigra) was grown in pots amended with 41 nm ZnO (200–600 mg/kg soil) and 47 nm CuO (12.5–50 mg/kg soil) nanoparticles (NPs) to analyze growth response and yield characteristics. B. nigra seed germination was not affected by CuO NPs, but significant toxicity was observed by ZnO NP treatment. Both NPs significantly increased the growth profile of B. nigra, i.e., the stem height, number of leaves, average leaf area, number of branches, and number of nodes per plant. Application of ZnO and CuO NPs brought a significant dose-dependent decrease in primary root length; however, the number of secondary roots increased in the presence of CuO NPs. The average number of flowers and pods per plant significantly increased in the presence of CuO NPs. The seed yield, average seed weight per plant, and seed diameter parameters were observed to be better in the presence of CuO NPs as compared with ZnO NPs. Total protein contents and glucosinolates increased in the seeds grown in the NP-amended soil, while total oil contents decreased. Oil analysis depicted that oleic acid and linolenic acid percentage decreased while erucic acid percentage increased in seeds in the presence of both NPs in the soil. An atomic absorption spectrophotometer showed accumulation of Cu and Zn in B. nigra in the following order: root > stem > leaves > seeds. The study concludes that CuO and ZnO NPs have detrimental effect on the B. nigra plant and yield. The release of NPs and type of metal in NPs might also have a positive effect on the plant; however, their concentration in the soil also matters.

MTH1 is involved in the toxic and carcinogenic long-term effects induced by zinc oxide and cobalt nanoparticles.

The nanoparticles (NPs) exposure-related oxidative stress is considered among the main causes of the toxic effects induced by these materials. However, the importance of this mechanism has been mostly explored at short term. Previous experience with cells chronically exposed to ZnO and Co NPs hinted to the existence of an adaptative mechanism contributing to the development of oncogenic features. MTH1 is a well-described enzyme expressed exclusively in cancer cells and required to avoid the detrimental consequences of its high prooxidant microenvironment. In the present work, a significantly marked overexpression was found when MTH1 levels were monitored in long-term ZnO and Co NP-exposed cells, a fact that correlates with acquired 2.5-fold and 3.75-fold resistance to the ZnO and Co NPs treatment, respectively. The forced stable inhibition of Mth1 expression by shRNA, followed by 6 additional weeks of exposure, significantly reduced this acquired resistance and sensitized cells to the oxidizing agents H2O2 and KBrO3. When the oncogenic phenotype of Mth1 knock-down cells was evaluated, we found a decrease in several oncogenic markers, including proliferation, anchorage-independent cell growth, and migration and invasion potential. Thus, MTH1 elicits here as a relevant player in the NPs-induced toxicity and carcinogenicity. This study is the first to give a mechanistic explanation for long-term NPs exposure-derived effects. We propose MTH1 as a candidate biomarker to unravel NPs potential genotoxic and carcinogenic effects, as its expression is expected to be elevated only under exposure conditions able to induce DNA damage and the acquisition of an oncogenic phenotype.

Deciphering the particle specific effects on metabolism in rat liver and plasma from ZnO nanoparticles versus ionic Zn exposure

Toxicity of ZnO nanoparticles (NPs) are often related to the release of Zn2+ ions due to their dissolution. Studies also suggest that the toxicity of ZnO NPs cannot be solely explained by the release of Zn2+ ions; however, there is a lack of direct evidence of ZnO particulate effects. This study compared the acute toxicity of ZnO NPs and ZnSO4 following intranasal exposure using a combination of metallomics and metabolomics approaches. Significant accumulation of Zn in the liver was only found in the ZnO NP treatment, with 29% of the newly accumulated Zn in the form of ZnO as revealed by X-ray fine structure spectroscopy (XAFS). This is the first direct evidence suggesting the persistence of ZnO NPs in liver upon intranasal exposure. Although both ZnO NPs and ZnSO4 altered the metabolite profiles, with some overlaps and considerable specificity, of both liver and plasma samples, more and distinct metabolites in the liver and opposite effects in the plasma were altered by ZnO NPs compared with ZnSO4, consistent with no accumulation of Zn detected in liver from ZnSO4. Specifically, a large number of antioxidant-related compounds and energetic substrates were exclusively elevated in the liver of ZnO NP-treated animals. These findings provided direct evidence that persistence of ZnO NPs induced particle-specific effects on the antioxidant systems and energy metabolism pathways.

Estimate of the Antifungal Activity and Phytotoxicity of ZnO Nanoparticles on Magnaporthe oryzae and Rice Cultivar Sakha 101 using Morphological, Biochemical and Molecular Markers

Riceblast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The current investigation aimed to estimate the antifungal activity and phytotoxicity effect of different concentrations of ZnO nanoparticles (0.0, 10, 25, 50, 100 and 200 mg/L) on M. oryzae and rice cultivar Sakha101 using morphological, biochemical and molecular markers. Five ISSR markers and seven RAPD primers were utilized to estimate the potentiality effects of ZnO nanoparticles (NPs). The effect of different rates and applications of ZnO NPs used to control rice blast disease and improve grain yield were estimated in the field during 2017 and 2018 growing seasons. The results showed that, in vitro antifungal assay of ZnO NPs showed a significant decrease in colony formation in comparison to control. Foliar application of ZnO NPs at 25 mg/L was the most effective treatments for mitigation rice blast at five days before inoculation. While under field conditions, foliar spray with 25 mg/L at nursery increased the grain yield to 4.366 ton/fed in season 2017 and to 4.625 ton/fed in 2018. Foliar spray with ZnO NPs of rice offer a practical and useful approach to improve rice grain yield and reduce leaf blast disease when applied at optimal concentrations. ZnO NPs at lower concentrations (10 and 25 mg/L) enhanced seed germination and improved seedling growth, while the higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. ZnO NPs treatments altered the expression patterns of seeds storage protein; induced newly synthesized isoforms and disappearance of existing ones. The obtained results using molecular markers confirmed that the lower concentrations of ZnO-NPs (10 and 25 mg/L) are considered as a good enhancement agent, as in case of rice cultivar Sakha101, using UBC 825 primer with 306 bp at concentration of 25 mg/L and OPA-9 primer with 948 bp at concentration of 10 mg/L. For M. oryzae the same trend of effects was appeared in case of UBC 880 primer with 994 bp at concentration of 25 mg/L and OPO-10 primer with 268 bp at concentration of 10 mg/L. In general, these results suggested that lower concentrations of ZnO NPs could be applied as an effective nano fertilizer for sustainable agriculture and food safety, and moreover, utilized as antifungal agent for rice blast disease.

Evaluation of phytotoxicity, cytotoxicity, and genotoxicity of ZnO nanoparticles in Vicia faba

Due to the accelerating use of manufactured nanomaterials, more research is needed to define their impact on plants. The present investigation aimed at evaluating the effect of different levels (0.0, 10, 25, 50, and 100mg/L) of ZnO nanoparticles (NPs) on Vicia faba during seed germination and seedling establishment. Additionally, V. faba root meristems were used as a model to monitor the cytotoxic and genotoxic effects resulting from exposure to ZnO NPs. The influence of ZnO NPs on three isoenzyme systems, peroxidase, α, and β esterase, was also evaluated using native-PAGE. Our results showed that lower concentrations of ZnO NPs (especially 10 and 25mg/L) enhanced seed germination and improved seedling growth, while higher concentrations (100 and 200mg/L) resulted in phytotoxicity. Cytological investigations of ZnO NPs-treated V. faba root cells denoted the clastogenic and aneugenic nature of ZnO NPs. Differential increase in mitotic index and significant alterations in cell cycle were observed upon exposure to ZnO NPs. High concentrations of ZnO NPs markedly induced chromosomal aberration, micronuclei, and vacuolated nuclei formation. Chromosomal breakage, chromosomal bridges, ring chromosomes, laggard chromosomes, and stickiness were also observed at a higher rate. The PAGE analysis showed that ZnO NPs treatments altered the expression patterns of all studied enzyme systems. Collectively, results from this work will help to further understand the phytotoxic effects of nanomaterials.

Effects of zinc oxide nanoparticles on the growth, photosynthetic traits, and antioxidative enzymes in tomato plants

With the dramatic increase in nanotechnologies, it has become probable that biological systems will be exposed to excess of nanoparticles (NPs). However, the impact of NPs on plants remains to be explored. The aim of this research was to determine the effects of ZnO NPs on tomato (Solanum lycopersicum L.) plants. Plant growth, photosynthetic characteristics, chlorophyll fluorescence parameters, and activities of antioxidative enzymes were measured in 35-d-old plants. The ZnO NP treatments significantly inhibited tomato root and shoot growth, decreased the content of chlorophylls a and b, and reduced photosynthetic efficiency and some other chlorophyll fluorescence parameters in a concentration-dependent manner. However, the supernatant of ZnO NP suspensions did not affect growth of tomato, despite the presence of small amounts of Zn2+. Taken together, these results suggest that toxic effects on tomato plants were from ZnO NPs, not from Zn2+ released into the solution; toxicity was likely caused by reduced chlorophyll content and damaged photochemical system, which in turn limited photosynthesis and led to the reduction in biomass accumulation. Also, ZnO NPs enhanced the transcription of genes related to antioxidant capacity, suggesting that ZnO NPs could enhance the defence response by increasing activities of antioxidant enzymes.

Zinc Oxide Nanoparticles Affect Biomass Accumulation and Photosynthesis in Arabidopsis.

Dramatic increase in the use of nanoparticles (NPs) in a variety of applications greatly increased the likelihood of the release of NPs into the environment. Zinc oxide nanoparticles (ZnO NPs) are among the most commonly used NPs, and it has been shown that ZnO NPs were harmful to several different plants. We report here the effects of ZnO NPs exposure on biomass accumulation and photosynthesis in Arabidopsis. We found that 200 and 300 mg/L ZnO NPs treatments reduced Arabidopsis growth by ∼20 and 80%, respectively, in comparison to the control. Pigments measurement showed that Chlorophyll a and b contents were reduced more than 50%, whereas carotenoid contents remain largely unaffected in 300 mg/L ZnO NPs treated Arabidopsis plants. Consistent with this, net rate of photosynthesis, leaf stomatal conductance, intercellular CO2 concentration and transpiration rate were all reduced more than 50% in 300 mg/L ZnO NPs treated plants. Quantitative RT-PCR results showed that expression levels of chlorophyll synthesis genes including CHLOROPHYLL A OXYGENASE (CAO), CHLOROPHYLL SYNTHASE (CHLG), COPPER RESPONSE DEFECT 1 (CRD1), MAGNESIUM-PROTOPORPHYRIN IX METHYLTRANSFERASE (CHLM) and MG-CHELATASE SUBUNIT D (CHLD), and photosystem structure gene PHOTOSYSTEM I SUBUNIT D-2 (PSAD2), PHOTOSYSTEM I SUBUNIT E-2 (PSAE2), PHOTOSYSTEM I SUBUNIT K (PSAK) and PHOTOSYSTEM I SUBUNIT K (PSAN) were reduced about five folds in 300 mg/L ZnO NPs treated plants. On the other hand, elevated expression, though to different degrees, of several carotenoids synthesis genes including GERANYLGERANYL PYROPHOSPHATE SYNTHASE 6 (GGPS6), PHYTOENE SYNTHASE (PSY) PHYTOENE DESATURASE (PDS), and ZETA-CAROTENE DESATURASE (ZDS) were observed in ZnO NPs treated plants. Taken together, these results suggest that toxicity effects of ZnO NPs observed in Arabidopsis was likely due to the inhibition of the expression of chlorophyll synthesis genes and photosystem structure genes, which results in the inhibition of chlorophylls biosynthesis, leading to the reduce in photosynthesis efficiency in the plants.