Morphological, proteomic and metabolomic insight into the effect of cerium dioxide nanoparticles to Phaseolus vulgaris L. under soil or foliar application

Navigating nanotoxicity: Unraveling nanomaterial-induced effects via multi-omics integration

The growing use of nanomaterials in industry and medicine raises significant concerns about their safety, particularly regarding their interactions with biological systems. Traditional toxicological methods, with limited throughput and mechanistic understanding, are increasingly being complemented by omics technologies. Genomics, transcriptomics, proteomics, and metabolomics provide comprehensive insights into the molecular mechanisms of nanomaterial toxicity and enable the identification of potential biomarkers. In addition, single-cell and spatial omics approaches are emerging as powerful tools to assess toxicity at the cellular and tissue levels, revealing heterogeneous responses and spatial distribution of nanomaterials. Despite their advantages, omics technologies face challenges in nanotoxicology, including large, complex data sets, integration difficulties, and a lack of standardized protocols. To address these challenges, we propose the development of new bioinformatics tools, multi-omics integration platforms, and standardized analysis processes to enhance research efficiency and accuracy. These efforts can provide a practical roadmap for integrating the application of omics technologies, including single-cell and spatial approaches, in the study of nanomaterial toxicity studies.

Cerium oxide nanoparticles: biogenic synthesis, characterization, and effects of foliar application on photosynthetic and antioxidant performance on Brassica juncea L

The term "green synthesis" refers to the use of sustainable and environmentally friendly methods to produce materials, chemicals, or nanoparticles (NPs). This approach emphasizes the use of renewable resources, energy-efficient processes, and non-toxic chemicals to minimize environmental impact. In our study, we synthesized cerium oxide NPs (CeO₂ NPs) of varying crystal sizes using leaf extract from the Moringa oleifera plant and evaluated their effects on the photosynthetic and antioxidant properties of mustard (Brassica juncea L.). X-ray diffraction (XRD) analysis confirmed the successful synthesis of CeO₂ NPs, with average crystal sizes determined using the Debye-Scherrer equation as 4.5 nm, 8.5 nm, and 15.4 nm (designated as A, B, and C respectively). Fourier transform infrared spectroscopy (FTIR) analysis revealed stretching frequencies at 550 cm⁻1, confirming the presence of Ce-O stretching bands and the use of natural compounds in the synthesis process. Scanning electron microscopy (SEM) analysis showed that the CeO₂ NPs were irregularly shaped and agglomerated, while transmission electron microscopy (TEM) analysis confirmed that the particles were spherical and polydisperse. Dynamic light scattering (DLS) and zeta potential analysis further confirmed the polydispersity and stability of synthesized NPs in solution. Following synthesis, the CeO₂ NPs were applied foliarly to mustard crops at concentrations of 50, 100, and 150 ppm. The results demonstrated that all concentrations of NPs enhanced growth, photosynthetic efficiency, and gaseous exchange parameters in mustard. Additionally, the NPs regulated balance between oxidation and reduction (redox) reactions in cell. It helps maintain cellular function by controlling reactive oxygen species (ROS) and antioxidants, preventing damage and ensuring normal metabolism. Notably, the 4.5 nm-sized NP (A) at a concentration of 100 ppm was the most effective in improving these parameters. CeO₂ NPs show promise as a sustainable alternative to traditional fertilizers and pesticides, contributing to more sustainable agricultural practices. This pioneering research highlights the potential of biogenically synthesized CeO₂ NPs in boosting crop performance, marking a significant advancement in agricultural nanotechnology.

Natural Biogenic Templates for Nanomaterial Synthesis: Advances, Applications, and Environmental Perspectives

This review explores the use of biogenic templates in nanomaterial synthesis, emphasizing their role in promoting environmentally sustainable nanotechnology. It categorizes various biogenic templates, including agricultural byproducts and microorganisms, stating their suitability for forming nanostructures due to their distinct properties. A comparative analysis of monostep and multistep synthesis methods is provided, focusing on their efficiencies and outcomes when using biogenic templates. Further, this review also highlights how these templates can generate complex nanostructures and hybrid materials with enhanced functionalities. Applications of biogenic templates across biomedicine, biotechnology, environmental science, and energy are discussed along with their utilization scope in agriculture and electronics. Benefits from nanostructures from biotemplates include sustainability, low cost, and reduced toxicity, but challenges like scalability, reproducibility, and regulatory compliance persist. Future research focuses on improving synthesis techniques, discovering new templates, and evaluating environmental and cytotoxic impacts, especially for biomedical uses. In conclusion, the review reaffirms the potential of biogenic templates in sustainable nanomaterial synthesis while highlighting the ongoing challenges that need to be addressed for broader adoption.

Metabolomics reveals that phosphatidylethanolamine can alleviate the toxicity of silica nanoparticles in human lung A549 cells

Silica nanoparticles (SiNPs) are widely utilized in occupational settings where they can cause lung damage through inhalation. The objective of this research was to explore the metabolic markers of SiNPs-induced toxicity on A549 cells by metabolomics and provide a foundation for studying nanoparticle-induced lung toxicity. Metabolomics analysis was employed to analyze the metabolites of SiNPs-treated A549 cells. LASSO regression was applied for selection, and protective measure experiments were conducted to validate the efficacy of selected potential toxicity mitigators. After SiNPs treatment, 23 differential metabolites were identified, including lipids, nucleotides, and organic oxidants. Pathway analysis revealed involvement in various biological processes. LASSO regression further identified six metabolites significantly associated with SiNPs toxicity. Notably, phosphatidylethanolamine (PE (14:1(9Z)/14:0)) showed enrichment in six significant metabolic pathways and with an AUC of 1 in the ROC curve. Protective measure experiments verified its protective effect on A549 cells and demonstrated its considerable inhibition of SiNPs-induced cytotoxicity. This study elucidated SiNPs-induced cytotoxicity on A549 cells and identified PE as a potential toxicity mitigator. These findings contribute to understanding the mechanisms of nanoparticle-induced lung toxicity and inform occupational health preventive strategies.

Nanoparticles: a promising tool against environmental stress in plants

With a focus on plant tolerance to environmental challenges, nanotechnology has emerged as a potent instrument for assisting crops and boosting agricultural production in the face of a growing worldwide population. Nanoparticles (NPs) and plant systems may interact molecularly to change stress response, growth, and development. NPs may feed nutrients to plants, prevent plant diseases and pathogens, and detect and monitor trace components in soil by absorbing their signals. More excellent knowledge of the processes of NPs that help plants survive various stressors would aid in creating more long-term strategies to combat these challenges. Despite the many studies on NPs' use in agriculture, we reviewed the various types of NPs and their anticipated molecular and metabolic effects upon entering plant cells. In addition, we discussed different applications of NPs against all environmental stresses. Lastly, we introduced agricultural NPs' risks, difficulties, and prospects.

Optimization of exogenous CeO2 nanoparticles on Pak choi (Brassica rapa L. var. chinensis) to alleviate arsenic stress

Arsenic (As) is a regulated hazardous substance that persists in the environment, causing issues related to environmental health, agriculture, and food safety. Cerium oxide nanoparticles (CeO2 NPs) are emerging sustainable solutions for alleviating heavy metal stress. However, their effectiveness and optimization for foliar application in reducing As stress, especially in Pak choi, has not been reported yet. Hence, this study aims to examine the effects of foliar application of CeO2 NPs (75,000,000, 150,000,000, and 300,000,000 ng/L) on the growth, nutrient availability, and antioxidant enzymatic activities of Pak choi plants under As stress. The findings showed that foliar application of 75,000,000 ng/L CeO2 NPs significantly increased shoot length (77.32%), root length (80.98%), and number of leaves (80.23%) as compared to control without NPs. The lowest dose of CeO2 NPs (75,000,000 ng/L) increased antioxidant enzyme activities such as peroxidase (86.10%), superoxide dismutase (81.48%), and catalase (52.07%), while significantly reducing malondialdehyde (44.02%), hydrogen peroxide (34.20%), and electrolyte leakage (43.53%). Furthermore, foliar application of 75,000,000 ng/L CeO2 NPs significantly increased the content of zinc (81.02%), copper (56.99%), iron (88.04%), manganese (68.37%), magnesium (76.83%), calcium (61.16%), and potassium (84.91%) in leaves when compared to control without NPs. The same trend was observed for shoot and root nutrient concentrations. Most importantly, 75,000,000 ng/L CeO2 NPs foliar application significantly reduced shoot As (45.11%) and root As (20.89%) concentration compared to control, providing a reassuring indication of their potential to reduce As concentration in plants. Our study's findings are of utmost importance as they indicate that lower concentrations of foliar-applied CeO2 NPs can be more effective in enhancing crop nutrition and reducing heavy metals than higher concentrations. This article is intended to present critical issues of As contamination in agricultural soils, which imposes substantial risks to crop productivity and food security.

Distinct accumulation patterns, translocation efficiencies, and impacts of nano-fertilizer and nano-pesticide in wheat through foliar versus soil application

The use of nano-chemicals in agriculture has been shown to enhance crop production through soil additions or foliar sprays. However, the accumulation pattern, translocation efficiency, mode of action of nanomaterials (NMs) via different application methods remain unclear. In this study, wheat was treated with CuO-NPs/CeO2-NPs (50 and 100 nm) for 21 days using soil and foliar application separately. Foliar spray resulted in higher accumulation and more efficient translocation of NMs compared to soil addition. Smaller NMs exhibited higher accumulation and transfer capabilities under the same application method. The accumulation of CuO-NPs was approximately 20 times greater than that of CeO2-NPs, particularly under the soil addition treatment. Scanning electron microscopy analysis demonstrated that NMs could directly enter wheat leaves via stomata during foliar application. Wheat growth was inhibited by roughly 15 % following CuO-NPs exposure, whereas no significant effects on growth were observed with CeO2-NPs. By integrating nontargeted metabolomics analysis with targeted physiological characteristics assessments, it was revealed that CuO-NPs mainly disturbed nitrogen metabolism pathways and induced oxidative damage. In contrast, CeO2-NPs enhanced carbohydrates related biological processes such as starch and sucrose metabolism, glycolysis, and TCA cycle, which are crucial for carbon metabolism. These findings suggest that the type of nanomaterial is a crucial factor to consider when evaluating their foliar or soil application in agriculture.

Uptake, Translocation, Toxicity, and Impact of Nanoparticles on Plant Physiological Processes

The application of nanotechnology in agriculture has increased rapidly. However, the fate and effects of various nanoparticles on the soil, plants, and humans are not fully understood. Reports indicate that nanoparticles exhibit positive and negative impacts on biota due to their size, surface property, concentration within the system, and species or cell type under test. In plants, nanoparticles are translocated either by apoplast or symplast pathway or both. Also, it is not clear whether the nanoparticles entering the plant system remain as nanoparticles or are biotransformed into ionic forms or other organic compounds. Controversial results on the toxicity effects of nanomaterials on the plant system are available. In general, the nanomaterial toxicity was exerted by producing reactive oxygen species, leading to damage or denaturation of various biomolecules. The intensity of cyto- and geno-toxicity depends on the physical and chemical properties of nanoparticles. Based on the literature survey, it is observed that the effects of nanoparticles on the growth, photosynthesis, and primary and secondary metabolism of plants are both positive and negative; the response of these processes to the nanoparticle was associated with the type of nanoparticle, the concentration within the tissue, crop species, and stage of growth. Future studies should focus on addressing the key knowledge gaps in understanding the responses of plants to nanoparticles at all levels through global transcriptome, proteome, and metabolome assays and evaluating nanoparticles under field conditions at realistic exposure concentrations to determine the level of entry of nanoparticles into the food chain and assess the impact of nanoparticles on the ecosystem.

Morphophysiological, biochemical, and nutrient response of spinach (Spinacia oleracea L.) by foliar CeO2 nanoparticles under elevated CO2

Nanomaterials offer considerable benefits in improving plant growth and nutritional status owing to their inherent stability, and efficiency in essential nutrient absorption and delivery. Cerium oxide nanoparticles (CeO2 NPs) at optimum concentration could significantly influence plant morpho-physiology and nutritional status. However, it remains unclear how elevated CO2 and CeO2 NPs interactively affect plant growth and quality. Accordingly, the ultimate goal was to reveal whether CeO2 NPs could alter the impact of elevated CO2 on the nutrient composition of spinach. For this purpose, spinach plant morpho-physiological, biochemical traits, and nutritional contents were evaluated. Spinach was exposed to different foliar concentrations of CeO2 NPs (0, 25, 50, 100 mg/L) in open-top chambers (400 and 600 CO2 μmol/mol). Results showed that elevated CO2 enhanced spinach growth by increasing photosynthetic pigments, as evidenced by a higher photosynthetic rate (Pn). However, the maximum growth and photosynthetic pigments were observed at the highest concentration of CeO2 NPs (100 mg/L) under elevated CO2. Elevated CO2 resulted in a decreased stomatal conductance (gs) and transpiration rate (Tr), whereas CeO2 NPs enhanced these parameters. No significant changes were observed in any of the measured biochemical parameters due to increased levels of CO2. However, an increase in antioxidant enzymes, particularly in catalase (CAT; 14.37%) and ascorbate peroxidase (APX; 10.66%) activities, was observed in high CeO2 NPs (100 mg/L) treatment under elevated CO2 levels. Regarding plant nutrient content, elevated CO2 significantly decreases spinach roots and leaves macro and micronutrients as compared to ambient CO2 levels. CeO2 NPs, in a dose-dependent manner, with the highest increase observed in 100 mg/L CeO2 NPs treatment and increased roots and shoots magnesium (211.62-215.49%), iron (256.68-322.77%), zinc (225.89-181.49%), copper (21.99-138.09%), potassium (121.46-138.89%), calcium (118.22-91.32%), manganese (133.15-195.02%) under elevated CO2. Overall, CeO2 NPs improved spinach growth and biomass and reverted the adverse effects of elevated CO2 on its nutritional quality. These findings indicated that CeO2 NPs could be used as an effective approach to increase vegetable growth and nutritional values to ensure food security under future climatic conditions.

GC-MS metabolomics of French lettuce (Lactuca Sativa L. var capitata) leaves exposed to bisphenol A via the hydroponic media

INTRODUCTION

Bisphenol A (BPA), an organic compound used to produce polycarbonate plastics and epoxy resins, has become a ubiquitous contaminant due to its high-volume production and constant release to the environment. Plant metabolomics can trace the stress effects induced by environmental contaminants to the variation of specific metabolites, making it an alternative way to study pollutants toxicity to plants. Nevertheless, there is an important knowledge gap in metabolomics applications in this area.

OBJECTIVE

Evaluate the influence of BPA in French lettuce (Lactuca Sativa L. var capitata) leaves metabolic profile by gas chromatography coupled to mass spectrometry (GC-MS) using a hydroponic system.

METHODS

Lettuces were cultivated in the laboratory to minimize biological variation and were analyzed 55 days after sowing (considered the plant's adult stage). Hexanoic and methanolic extracts with and without derivatization were prepared for each sample and analyzed by GC-MS.

RESULTS

The highest number of metabolites was obtained from the hexanoic extract, followed by the derivatized methanolic extract. Although no physical differences were observed between control and contaminated lettuce leaves, the multivariate analysis determined a statistically significant difference between their metabolic profiles. Pathway analysis of the most affected metabolites showed that galactose metabolism, starch and fructose metabolism and steroid biosynthesis were significantly affected by BPA exposure.

CONCLUSIONS

The preparation of different extracts from the same sample permitted the determination of metabolites with different physicochemical properties. BPA alters the leaves energy and membrane metabolism, plant growth could be affected at higher concentrations and exposition times.

Effect of biochar amendment on bacterial community and their role in nutrient acquisition in spinach (Spinacia oleracea L.) grown under elevated CO2

Global climate change is anticipated to shift the soil bacterial community structure and plant nutrient utilization. The use of biochar amendment can positively influence soil bacterial community structure, soil properties, and nutrient use efficiency of crops. However, little is known about the underlying mechanism and response of bacterial community structure to biochar amendment, and its role in nutrient enhancement in soil and plants under elevated CO2. Herein, the effect of biochar amendment (0, 0.5, 1.5%) on soil bacterial community structure, spinach growth, physiology, and soil and plant nutrient status were investigated under two CO2 concentrations (400 and 600 μmol mol-1). Findings showed that biochar application 1.5% (B.2.E) significantly increased the abundance of the bacterial community responsible for growth and nutrient uptake i.e. Firmicutes (42.25%) Bacteroidetes (10.46%), and Gemmatimonadetes (125.75%) as compared to respective control (CK.E) but interestingly abundance of proteobacteria decreased (9.18%) under elevated CO2. Furthermore, the soil available N, P, and K showed a significant increase in higher biochar-amended treatments under elevated CO2. Spinach plants exhibited a notable enhancement in growth and photosynthetic pigments when exposed to elevated CO2 levels and biochar, as compared to ambient CO2 conditions. However, there was variability observed in the leaf gas exchange attributes. Elevated CO2 reduced spinach roots and leaves nutrient concentration. In contrast, the biochar amendment (B2.E) enhanced root and shoot Zinc (494.99%-155.33%), magnesium (261.15%-183.37%), manganese (80.04%-152.86%), potassium (576.24%-355.17%), calcium (261.88%-165.65%), copper (325.42%-282.53%) and iron (717.63%-177.90%) concentration by influencing plant physiology and bacterial community. These findings provide insights into the interaction between plant and bacterial community under future agroecosystems in response to the addition of biochar contributing to a deeper understanding of ecological dynamics.

Nanotechnology in Agriculture: Manganese Ferrite Nanoparticles as a Micronutrient Fertilizer for Wheat

Limited research has focused on nanoparticle (NP) applications' impact on edible wheat parts in a field environment. Here, we studied the nutritional quality of edible parts of wheat (Triticum aestivum L.) with a field experiment by spraying MnFe2O4 nanoparticles. Wheat was foliar sprayed with 0, 25, 50, and 100 mg/L composite manganese ferrite (MnFe2O4) NPs during 220 d of a growth period. Ionic controls were prepared using the conventional counterparts (MnSO4·H2O and FeSO4·7H2O) to compare with the 100 mg/L MnFe2O4 NPs. After three consecutive foliar applications, nanoparticles demonstrated a substantial elevation in grain yield and harvest index, exhibiting a noteworthy increase to 5.0 ± 0.12 t/ha and 0.46 ± 0.001 in the 100 mg/L NP dose, respectively, concomitant with a 14% enhancement in the grain number per spike. Fe, Mn, and Ca content in grain increased to 77 ± 2.7 mg/kg, 119 ± 2.8 mg/kg, and 0.32 ± 7.9 g/kg in the 100 mg/L NPs, respectively. Compared to the ion treatment, the 100 mg/L NP treatments notably boosts wheat grain crude protein content (from 13 ± 0.79% to 15 ± 0.58%) and effectively lowers PA/Fe levels (from 11 ± 0.7 to 9.3 ± 0.5), thereby improving Fe bioavailability. The VSM results exhibited a slight superparamagnetic behavior, whereas the grains and stems exhibited diamagnetic behavior. The results indicate that the nanomaterial did not accumulate in the grains, suggesting its suitability as an Fe and Mn-rich fertilizer in agriculture. Above all, the foliar application of nanocomposites increased the concentrations of Fe, Mn, and Ca in wheat grains, accompanied by a significant enhancement in grain yield. Therefore, the research results indicate that the foliar application of MnFe2O4 NPs can positively regulate wheat grains' nutritional quality and yield.

Evaluation of the effect of nanoparticles on the cultivation of edible plants by ICP-MS: a review

Nanoparticle (NP) applications aiming to boost plant biomass production and enhance the nutritional quality of crops hae proven to be a valuable ally in enhancing agricultural output. They contribute to greater food accessibility for a growing and vulnerable population. These nanoscale particles are commonly used in agriculture as fertilizers, pesticides, plant growth promoters, seed treatments, opportune plant disease detection, monitoring soil and water quality, identification and detection of toxic agrochemicals, and soil and water remediation. In addition to the countless NP applications in food and agriculture, it is possible to highlight many others, such as medicine and electronics. However, it is crucial to emphasize the imperative need for thorough NP characterization beyond these applications. Therefore, analytical methods are proposed to determine NPs' physicochemical properties, such as composition, crystal structure, size, shape, surface charge, morphology, and specific surface area, detaching the inductively coupled plasma mass spectrometry (ICP-MS) that allows the reliable elemental composition quantification mainly in metallic NPs. As a result, this review highlights studies involving NPs in agriculture and their consequential effects on plants, with a specific focus on analyses conducted through ICP-MS. Given the numerous applications of NPs in this field, it is essential to address their presence and increase in the environment and humans since biomagnification and biotransformation effects are studies that should be further developed. In light of this, the demand for rapid, innovative, and sensitive analytical methods for the characterization of NPs remains paramount.

Exogenous titanium dioxide nanoparticles alleviate cadmium toxicity by enhancing the antioxidative capacity of Tetrastigma hemsleyanum

Nanotechnology is one of the most recent approaches employed to defend plants against both biotic and abiotic stress including heavy metals such as Cadmium (Cd). In this study, we evaluated the effects of titanium dioxide (TiO2) nanoparticles (TiO2 NPs) in alleviating Cd stress in Tetrastigma hemsleyanum Diels et Gilg. Compared with Cd treatment, TiO2 NPs decreased leaf Cd concentration, restored Cd exposure-related reduction in the biomass to about 69% of control and decreased activities of antioxidative enzymes. Integrative analysis of transcriptome and metabolome revealed 325 differentially expressed genes associated with TiO2 NP treatment, most of which were enriched in biosynthesis of secondary metabolites. Among them, the flavonoid and phenylpropanoid biosynthetic pathways were significantly regulated to improve the growth of T. hemsleyanum when treated with Cd. In the KEGG Markup Language (KGML) network analysis, we found some commonly regulated pathways between Cd and Cd+TiO2 NP treatment, including phenylpropanoid biosynthesis, ABC transporters, and isoflavonoid biosynthesis, indicating their potential core network positions in controlling T. hemsleyanum response to Cd stress. Overall, our findings revealed a complex response system for tolerating Cd, encompassing the transportation, reactive oxygen species scavenging, regulation of gene expression, and metabolite accumulation in T. hemsleyanum. Our results indicate that TiO2 NP can be used to reduce Cd toxicity in T. hemsleyanum.

Proteomic insights to decipher nanoparticle uptake, translocation, and intercellular mechanisms in plants

Advent of proteomic techniques has made it possible to identify a broad spectrum of proteins in living systems. Studying the impact of nanoparticle (NP)-mediated plant protein responses is an emerging field. NPs are continuously being released into the environment and directly or indirectly affect plant's biochemistry. Exposure of plants to NPs, especially crops, poses a significant risk to the food chain, leading to changes in underlying metabolic processes. Once absorbed by plants, NPs interact with cellular proteins, thereby inducing changes in plant protein patterns. Based on the reactivity, properties, and translocation of nanoparticles, NPs can interfere with proteins involved in various cellular processes in plants such as energy regulation, redox metabolism, and cytotoxicity. Such interactions of NPs at the subcellular level enhance ROS scavenging activity, especially under stress conditions. Although higher concentrations of NPs induce ROS production and hinder oxidative mechanisms under stress conditions, NPs also mediate metabolic changes from fermentation to normal cellular processes. Although there has been lots of work conducted to understand the different effects of NPs on plants, the knowledge of proteomic responses of plants toward NPs is still very limited. This review has focused on the multi-omic analysis of NP interaction mechanisms with crop plants mainly centering on the proteomic perspective in response to both stress and non-stressed conditions. Furthermore, NP-specific interaction mechanisms with the biological pathways are discussed in detail.

Assessing the Impacts of Cu and Mo Engineered Nanomaterials on Crop Plant Growth Using a Targeted Proteomics Approach

In this study, we investigated the effects of molybdenum (Mo)-based nanofertilizer and copper (Cu)-based nanopesticide exposure on wheat through a multifaceted approach, including physiological measurements, metal uptake and translocation analysis, and targeted proteomics analysis. Wheat plants were grown under a 16 h photoperiod (light intensity 150 μmol·m-2·s-1) for 4 weeks at 22 °C and 60% humidity with 6 different treatments, including control, Mo, and Cu exposure through root and leaf. The exposure dose was 6.25 mg of element per plant through either root or leaf. An additional low-dose (0.6 mg Mo/plant) treatment of Mo through root was added after phytotoxicity was observed. Using targeted proteomics approach, 24 proteins involved in 12 metabolomic pathways were quantitated to understand the regulation at the protein level. Mo exposure, particularly through root uptake, induced significant upregulation of 16 proteins associated with 11 metabolic pathways, with the fold change (FC) ranging from 1.28 to 2.81. Notably, a dose-dependent response of Mo exposure through the roots highlighted the delicate balance between nutrient stimulation and toxicity as a high Mo dose led to robust protein upregulation but also resulted in depressed physiological measurements, while a low Mo dose resulted in no depression of physiological measurements but downregulations of proteins, especially in the first leaf (0.23 < FC < 0.68) and stem (0.13 < FC < 0.68) tissues. Conversely, Cu exposure exhibited tissue-specific effects, with pronounced downregulation (18 proteins involved in 11 metabolic pathways) particularly in the first leaf tissues (root exposure: 0.35 < FC < 0.74; leaf exposure: 0.49 < FC < 0.72), which indicated the quick response of plants to Cu-induced stress in the early stage of exposure. By revealing the complexities of plants' response to engineered nanomaterials at both physiological and molecular levels, this study provides insights for optimizing nutrient management practices in crop production and advancing toward sustainable agriculture.

Integrated microbiome and multi-omics analysis reveal the molecular mechanisms of Eisenia fetida in response to biochar-derived dissolved and particulate matters

At present, most ecotoxicological studies are still confined to focusing on the harmful effects of biochar itself on soil fauna. However, the potential ecotoxicity of different components separated from biochar to terrestrial invertebrates remains poorly understood. In this study, the dissolved matter (DM) and particulate matter (PM) were separated from biochar (BC) and then introduced into the soil-earthworm system to investigate the response mechanism of earthworms at the molecular level. The results showed that BC and DM exposure caused an increase in the abundance of Proteobacteria in the cast bacterial community, suggesting the dysbiosis of intestinal microbiota. It was also observed that the cast bacterial communities were more sensitive to DM exposure than PM exposure. Transcriptomic analysis showed that BC and DM exposure induced significant enrichment of functional pathways related to infectious and neuropathic diseases. Metabolomic profiling manifested that DM exposure caused metabolic dysfunction, antioxidant and detoxification abilities recession. Furthermore, significant differences in the responses of earthworms at transcriptomic and metabolic levels confirmed that DM exhibited greater ecotoxicity than PM. This study highlighted the significant contributions of dissolved matter to the ecotoxicity of biochar from the perspective of transcriptomic and metabolomic profiles.

Synthesis and characterization of CeO2 and SiO2 nanoparticles and their effect on growth parameters and the antioxidant defense system in Vigna mungo L. Hepper

Engineered nanoparticles (NPs) have recently attracted a lot of attention after being tested in various agricultural plants. This paper reports the green synthesis of CeO2 NPs and SiO2 NPs from leaf extracts of Nyctanthes arbor-tristis. The physical characteristics of the produced nanoparticles were then determined using UV-visible spectroscopy, transmission electron microscopy (TEM), fluorescence spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Furthermore, the interaction effects of cerium oxide NPs (C1, C2, and C3) and silicon dioxide NPs (S1, S2, and S3) at 10 mg/L on blackgram (Vigna mungo L.) were evaluated. CeO2 and SiO2 NPs treatments enhanced the growth performance of the plants by causing a decrease in superoxide radical (SOR) and H2O2 via improving antioxidant enzymes. These findings imply that the size and shape of CeO2 and SiO2 NPs provide defense against oxidative damage to the blackgram.

Nanotoxicity assessment in plants: an updated overview

Nanotechnology is rapidly emerging and innovative interdisciplinary field of science. The application of nanomaterials in agricultural biotechnology has been exponentially increased over the years that could be attributed to their uniqueness, versatility, and flexibility. The overuse of nanomaterials makes it crucial to determine their fate and distribution in the in vitro (in cell and tissue cultures) and in vivo (in living species) biological environments by investigating the nano-biointerface. The literature states that the beneficial effects of nanoparticles come along with their adverse effects, subsequently leading to an array of short-term and long-term toxicities. It has been evident that the interplay of nanoparticles with abiotic and biotic communities produces several eco-toxicological effects, and the physiology and biochemistry of crops are greatly influenced by the metabolic alterations taking place at cellular, sub-cellular, and molecular levels. Numerous risk factors affect nanoparticle's accumulation, translocation, and associated cytogenotoxicity. This review article summarizes the contributing factors, possible mechanisms, and risk assessment of hazardous effects of various types of nanoparticles to plant health. The methods for evaluating the plant nanotoxicity parameters have been elaborated. Conclusively, few recommendations are put forward for designing safer, high-quality nanomaterials to protect and maintain environmental safety for smarter agriculture demanded by researchers and industrialists.

Foliar cadmium uptake, transfer, and redistribution in Chili: A comparison of foliar and root uptake, metabolomic, and contribution

Atmospheric deposition is an essential cadmium (Cd) pollution source in agricultural ecosystems, entering crops via roots and leaves. In this study, atmospherically deposited Cd was simulated using cadmium sulfide nanoparticles (CdS_N), and chili (Capsicum frutescens L.) was used to conduct a comparative foliar and root experiment. Root and foliar uptake significantly increased the Cd content of chili tissues as well as the subcellular Cd content. Scanning electron microscopy and high-resolution secondary ion mass spectrometry showed that Cd that entered the leaves via stomata was fixed in leaf cells, and the rest was mainly through phloem transport to the other organs. In leaf, stem, and root cell walls, Cd signal intensities were 47.4%, 72.2%, and 90.0%, respectively. Foliar Cd uptake significantly downregulated purine metabolism in leaves, whereas root Cd uptake inhibited stilbenoid, diarylheptanoid, and gingerol biosynthesis in roots. Root uptake contributed 90.4% Cd in fruits under simultaneous root and foliar uptake conditions attributed to xylem and phloem involvement in Cd translocation. Moreover, root uptake had a more significant effect on fruit metabolic pathways than foliar uptake. These findings are critical for choosing pollution control technologies and ensuring food security.

Optimization of Targeted Plant Proteomics Using Liquid Chromatography with Tandem Mass Spectrometry (LC-MS/MS)

This study was conducted to optimize a targeted plant proteomics approach from signature peptide selection and liquid chromatography with tandem mass spectrometry (LC-MS/MS) analytical method development and optimization to sample preparation method optimization. Three typical protein extraction and precipitation methods, including trichloroacetic acid (TCA)/acetone method, phenol method, and TCA/acetone/phenol method, and two digestion methods, including trypsin digestion and LysC/trypsin digestion, were evaluated for selected proteins related to the impact of engineered nanomaterials (ENMs) on wheat (Triticum aestivum) plant growth. In addition, we compared two plant tissue homogenization methods: grinding freeze-dried tissue and fresh tissue into a fine powder using a mortar and pestle aided with liquid nitrogen. Wheat plants were grown under a 16 h photoperiod (light intensity 150 μmol·m^-2·s^-1) for 4 weeks at 22 °C with a relative humidity of 60% and were watered daily to maintain a 70-90% water content in the soil. Processed samples were analyzed with an optimized LC-MS/MS method. The concentration of selected signature peptides for the wheat proteins of interest indicated that the phenol extraction method using fresh plant tissue, coupled with trypsin digestion, was the best sample preparation method for the targeted proteomics study. Overall, the optimized approach yielded the highest total peptide concentration (68,831 ng/g, 2.4 times the lowest concentration) as well as higher signature peptide concentrations for most peptides (19 out of 28). In addition, three of the signature peptides could only be detected using the optimized approach. This study provides a workflow for optimizing targeted proteomics studies.

A comparative study of the accumulation and detoxification of copper and zinc in Chlamydomonas reinhardtii: The role of extracellular polymeric substances

Extracellular polymeric substances (EPS) form an interface between microalgae and the surrounding water environment. Copper (Cu) and zinc (Zn) are essential micronutrients but may negatively affect microbial growth when their concentrations reach toxic thresholds. However, how EPS affect the accumulation and resistance of Cu and Zn in microalgae remains largely unknown. Here, we investigated EPS production upon Cu/Zn exposure and compared the tolerance strategies to the two metals by Chlamydomonas reinhardtii with and without EPS. Microalgal EPS synthesis was induced by Cu/Zn treatments, and the functional groups of polysaccharides and proteins were involved in complexation with metal ions. The extraction of EPS aggravated the toxicity and reduced the removal of metals from solution, but the effect was more pronounced for Cu than for Zn. Copper bound on the cell surface accounted for 54.6 ± 2.0 % of the Cu accumulated by C. reinhardtii, whose EPS components strongly correlated with Cu adsorption. In contrast, 74.3 ± 3.0 % of accumulated Zn was absorbed in cells, and glutathione synthesis was significantly induced. Redundancy and linear correlation analyses showed that the polysaccharide, protein and DNA contents in EPS were significantly correlated with Cu accumulation, absorption and adsorption but not with Zn. Data fitted to a Michaelis-Menten model further showed that the EPS-intact cells had higher binding capacity for Cu²⁺ but not for Zn²⁺. These differential impacts of EPS on Cu/Zn sorption and detoxification contribute to a more comprehensive understanding of the roles of microalgal EPS in the biogeochemical cycle of metals.

Engineered nanoparticles in plant growth: Phytotoxicity concerns and the strategies for their attenuation

In the agricultural sector, the use of engineered nanoparticles (ENPs) has been acclaimed as the next big thing for sustaining and increasing crop productivity. A vast amount of literature is available regarding the growth-promoting attributes of different ENPs. In this context, it has been emphasized that the ENPs can bolster vegetative growth, leaf development, and seed setting and also help in mitigating the effects of abiotic and biotic stresses. At the same time, there have been a lot of speculations and concerns regarding the phytotoxicity of ENPs off-late. In this connection, many research articles have presented the negative effects of ENPs on plant systems. These studies have highlighted that almost all the ENPs impart a certain degree of phytotoxicity in terms of reduction in growth, biomass, impairment of photosynthesis, oxidative status of plant cells, etc. Mostly, the ENPs based on metal or metal oxides (Cd, Cr, Pb, Ag, Ce, etc.) and nonmetals (C) that are introduced into the environment are known to incite inhibitory effects. However, the phytotoxicity of ENPs are known to be determined mostly by the chemical nature of the element, size, surface charge, coating molecules, and abiotic factors like pH and light. This review article, therefore, elucidates the phytotoxic properties of different ENPs and the plant responses induced at the molecular level subjected to nanoparticle exposure. Moreover, the article highlights the probable strategies that may be adopted for the suppression of the phytotoxicity of ENPs to ensure the safe and sustainable application of ENPs in crop fields.

Foliar application of nanoceria attenuated cadmium stress in okra (Abelmoschus esculentus L.)

Foliar application of nanoparticles (NPs) as a means for ameliorating abiotic stress is increasingly employed in crop production. In this study, the potential of CeO₂-NPs as stress suppressants for cadmium (Cd)-stressed okra (Abelmoschus esculentus) plants was investigated, using two cycles of foliar application of CeO₂-NPs at 200, 400, and 600 mg/l. Compared to untreated stressed plants, Cd-stressed plants treated with CeO₂-NPs presented higher pigments (chlorophyll a and carotenoids). In contrast, foliar applications did not alter Cd root uptake and leaf bioaccumulation. Foliar CeO₂-NPs application modulated stress enzymes (APX, SOD, and GPx) in both roots and leaves of Cd-stressed plants, and led to decreases in Cd toxicity in plant's tissues. In addition, foliar application of CeO₂-NPs in Cd-stressed okra plants decreased fruit Cd contents, and improved fruit mineral elements and bioactive compounds. The infrared spectroscopic analysis of fruit tissues showed that foliar-applied CeO₂-NPs treatments did not induce chemical changes but induced conformational changes in fruit macromolecules. Additionally, CeO₂-NPs applications did not alter the eating quality indicator (Mg/K ratio) of okra fruits. Conclusively, the present study demonstrated that foliar application of CeO₂-NPs has the potential to ameliorate Cd toxicity in tissues and improve fruits of okra plants.

The comparative effects of manganese nanoparticles and their counterparts (bulk and ionic) in Artemisia annua plants via seed priming and foliar application

The world has experienced an unprecedented boom in nanotechnology. Nanoparticles (NPs) are likely to act as biostimulants in various plants due to having high surface/volume value. However, understanding the actual effect of NPs is essential to discriminate them from other counterparts in terms of being applicable, safe and cost-effective. This study aimed to assay the impact of manganese(III) oxide (Mn₂O₃)-NPs via seed-priming (SP) and a combination of SP and foliar application (SP+F) on Artemisia. annua performance at several times intervals and comparison with other available manganese (Mn) forms. Our findings indicate that SP with MnSO₄ and Mn₂O₃-NPs stimulates the processes that occur prior to germination and thus reduces the time for radicle emergence. In both applications (i.e., SP and +F), none of the Mn treatments did show adverse phytotoxic on A. annua growth at morpho-physio and biochemical levels except for Mn₂O_3, which delayed germination and further plant growth, subsequently. Besides, from physio-biochemical data, it can be inferred that the general mechanism mode of action of Mn is mainly attributed to induce the photosynthetic processes, stimulate the superoxide dismutase (SOD) activity, and up-regulation of proline and phenolic compounds. Therefore, our results showed that both enzymatic and non-enzymatic antioxidants could be influenced by the application of Mn treatments in a type-dependent manner. In general, this study revealed that Mn₂O₃-NPs at the tested condition could be used as biostimulants to improve germination, seedling development and further plant growth. However, they are not as effective as MnSO₄ treatments. Nonetheless, these findings can be used to consider and develop Mn₂O₃-NPs priming in future studies to improve seed germination and seedling quality in plants.

Selenium nanoparticles reduce Ce accumulation in grains and ameliorate yield attributes in mung bean (Vigna radiata) exposed to CeO2

Exposure of crops to CeO₂ nanoparticles (nCeO₂) in agricultural environments impact crop quality and human health. In this regard, the effects of selenium nanoparticles (nSe) on the yield and quality of Vigna radiata (L.) exposed to nCeO₂ were investigated. The experiment was carried out as a factorial with two factors: NPs (nCeO₂, and nSe) as factor one and concentrations as factor two [(0, 250, 500 and 1000 mg/L nCeO₂; 0, 25, 50 and 75 mg/L nSe)]. Nanoparticles were foliar applied to 45-day old mung bean shoot in two steps and one-week interval. At 250-1000 mg/L, nCeO₂ increased P, protein and Ce accumulation in grain. Additionally, at 1000 mg/L, the nCeO_2, significantly decreased seed number, yield, Fe, and Zn storage in seeds. Conversely, at 25 and 50 mg/L, nSe stimulated the growth and yield of mung bean, and significantly increased P, Fe, Zn, and Se in seeds, but reduced the protein content in seeds. The Se₂₅+Ce₂₅₀ and Se₅₀+Ce₂₅₀ significantly increased pod number, seed number, grain weight, yield, Fe, Zn and Se storage in grains. In contrast, the Ce accumulation in seeds decreased in all combination treatments (nCeO₂ + nSe) compared to their respective single nCeO₂ treatments. Moreover, in the plants exposed to high nCeO₂ concentrations, nSe application resulted in undamaged vacuoles, less starch granules' accumulation, significant yield improvement, and elevated Fe, Se, and Zn in seeds. Data suggest that selenium nanoparticles prevent nCeO₂ stress in mung bean and improve grain production and quality.

Role of foliar biostimulants (of plant origin) on grapevine adaptation to climate change

Heat waves and drought stress are typical aspects of current climate change, significantly affecting the grapevine physiology in many world growing areas. Biostimulants can play an important role in reducing the negative effects of climate change; that’s why this experiment was set up in order to test two new foliar biostimulants (protein hydrolysates of plant origin). The field experiment was carried out in 2017 and 2018 in Oltrepo pavese area (Lombardia region, northwest Italy, 270 m asl), on a six-year-old vineyard of V. vinifera L. cv. Merlot clone 181 grafted on Gravesac, Guyot trellis, 4,000 vines/ha and not irrigated. Two new protein hydrolysates of plant origin were sprayed twice, just after fruit set and 15 days later, by using 2.5 L/ha. Leaf proteomics and metabolomics were studied in 2017, while productive and qualitative data were recorded in both years at harvest (September 1st, 2017 and August 28th 2018). The most significant findings were: (a) the treatments slowed down the grape ripening, by stimulating vegetative activity and reducing sugar accumulation; (b) less heat and drought stress symptoms were observed in the canopies of treated vines, as compared to the control ones.

Effect of foliar and root exposure to polymethyl methacrylate microplastics on biochemistry, ultrastructure, and arsenic accumulation in Brassica campestris L

Despite the serious risk of microplastic pollution in the roots and leaves of crops, the phytotoxicity of microplastics (introduced via different exposure routes) in leafy vegetables remain insufficiently understood. Here, the effects of the root and foliar exposure of polymethyl methacrylate microplastic (PMMAMPs) on phytotoxicity, As accumulation, and subcellular distribution were investigated in rapeseed (Brassica campestris L). The relative chlorophyll content under PMMAMPs treatment decreased with time, and the 0.05 g L^-1 root exposure decreased it significantly (by 9.97-20.48%, P < 0.05). In addition, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX) activities in rapeseed were more sensitive to PMMAMPs introduced through root exposure than through foliar exposure. There was dose-dependent ultrastructural damage, and root exposure had a greater impact than foliar exposure on root tip cells and chloroplasts. PMMAMPs entered the shoots and roots of rapeseed through root exposure. Under foliar exposure, PMMAMPs promoted As accumulation in rapeseed by up to 75.6% in shoots and 68.2% in roots compared to that under control (CK). As content in cell wall under PMMAMP treatments was 3.6-5.3 times higher than that of CK, as indicated by subcellular component results. In general, root exposure to PMMAMPs resulted in a stronger physiological impact and foliar exposure led to increased As accumulation in rapeseed.

Proteomic evaluation of nanotoxicity in aquatic organisms: A review

The alteration of organisms protein functions by engineered nanoparticles (ENPs) is dependent on the complex interplay between their inherent physicochemical properties (e.g., size, surface coating, shape) and environmental conditions (e.g., pH, organic matter). To date, there is increasing interest on the use of 'omics' approaches, such as proteomics, genomics, and others, to study ENPs-biomolecules interactions in aquatic organisms. However, although proteomics has recently been applied to investigate effects of ENPs and associated mechanisms in aquatic organisms, its use remain limited. Herein, proteomics techniques widely applied to investigate ENPs-protein interactions in aquatic organisms are reviewed. Data demonstrates that 2DE and mass spectrometry and/or their combination, thereof, are the most suitable techniques to elucidate ENPs-protein interactions. Furthermore, current status on ENPs and protein interactions, and possible mechanisms of nanotoxicity with emphasis on those that exert influence at protein expression levels, and key influencing factors on ENPs-proteins interactions are outlined. Most reported studies were done using synthetic media and essay protocols and had wide variability (not standardized); this may consequently limit data application in actual environmental systems. Therefore, there is a need for studies using realistic environmental concentrations of ENPs, and actual environmental matrixes (e.g., surface water) to aid better model development of ENPs-proteins interactions in aquatic systems.

Transcriptome analysis of lipid metabolism in response to cerium stress in the oleaginous microalga Nannochloropsis oculata

Nannochloropsis oculata can accumulate large amounts of lipids under rare earth element (REE) conditions. However, the lipid accumulation mechanism responsible for REE stress has not been elucidated. In this study, the effects of cerium (the most abundant REE) on the growth and lipid accumulation of N. oculata were investigated. The de novo transcriptome data of N. oculata under cerium conditions were subsequently collected and analyzed. The results showed that N. oculata exhibited good cerium-resistance ability, showed slightly decrease in biomass but significantly increase in lipid content (55.8 % dry cell weight) under 6.0 mg/L cerium condition. Meanwhile, about 83.4 % cerium was biological fixated. Through transcriptome analysis, we found that the inhibited photosynthesis and carbon fixation pathways coupled with the stress-sensitive expression of ribosome biogenesis genes acclimatized the cells to REE stress. The active glycolysis pathway accelerated carbon flux to pyruvate and acetyl-CoA, and the upregulation of glycerol kinase and phosphatidate cytidylyltransferase genes further induced lipid accumulation. In addition, cerium downregulated the acyl-CoA oxidase and triacylglycerol lipase genes, which inhibited the degradation of lipids. Therefore, different responses to cerium demonstrate how N. oculata cells adapt to REE stress, and this knowledge may be used to extend our understanding of triacylglycerol (TAG) and the synthesis of other important metabolites.

Nanoparticle-based toxicity in perishable vegetable crops: Molecular insights, impact on human health and mitigation strategies for sustainable cultivation

With the advancement of nanotechnology, the use of nanoparticles (NPs) and nanomaterials (NMs) in agriculture including perishable vegetable crops cultivation has been increased significantly. NPs/NMs positively affect plant growth and development, seed germination, plant stress management, and postharvest handling of fruits and vegetables. However, these NPs sometimes cause toxicity in plants by oxidative stress and excess reactive oxygen species production that affect cellular biomolecules resulting in imbalanced biological and metabolic processes in plants. Therefore, information about the mechanism underlying interactions of NPs with plants is important for the understanding of various physiological and biochemical responses of plants, evaluating phytotoxicity, and developing mitigation strategies for vegetable crops cultivation. To address this, recent morpho-physiological, biochemical and molecular insights of nanotoxicity in the vegetable crops have been discussed in this review. Further, factors affecting the nanotoxicity in vegetables and mitigation strategies for sustainable cultivation have been reviewed. Moreover, the bioaccumulation and biomagnification of NPs and associated phytotoxicity can cause serious effects on human health which has also been summarized. The review also highlights the use of advanced omics approaches and interdisciplinary tools for understanding the nanotoxicity and their possible use for mitigating phytotoxicity.

Integrative proteomics and metabolomics approach to elucidate metabolic dysfunction induced by silica nanoparticles in hepatocytes

Silica nanoparticles (SiNPs) are derived from manufactured materials and the natural environment, and they cause detrimental effects on human health via various exposure routes. The liver is proven to be a key target organ for SiNP toxicity; however, the mechanisms causing toxicity remain largely uncertain. Here, we investigated the effects of SiNPs on the metabolic spectrum in hepatocytes via integrative analyses of proteomics and metabolomics. First, a proteomic analysis was used to screen for critical proteins (including RPL3, HSP90AA1, SOD, PGK1, GOT1, and PNP), indicating that abnormal protein synthesis, protein misfolding, oxidative stress, and metabolic dysfunction may contribute to SiNP-induced hepatotoxicity. Next, metabolomic data demonstrated that SiNPs caused metabolic dysfunction by altering vital metabolites (including glucose, alanine, GSH, CTP, and ATP). Finally, a systematic bioinformatic analysis of protein-metabolite interactions showed that SiNPs disturbed glucose metabolism (glycolysis and pentose phosphate pathways, amino acid metabolism (alanine, aspartate, and glutamate), and ribonucleotide metabolism (purine and pyrimidine). These metabolic dysfunctions could exacerbate oxidative stress and lead to liver injury. Moreover, SOD, TKT, PGM1, GOT1, PNP, and NME2 may be key proteins for SiNP-induced hepatotoxicity. This study revealed the metabolic mechanisms underlying SiNP-induced hepatotoxicity and illustrated that integrative omics analyses can be a powerful approach for toxicity evaluations and risk assessments of nanoparticles.

A comprehensive study of selenium and cerium oxide nanoparticles on mung bean: Individual and synergistic effect on photosynthesis pigments, antioxidants, and dry matter accumulation

In this study, the interaction effects of CeO₂ NPs (250, 500 and 1000 mg L^-1) and Se NPs (25, 50 and 75 mg L^-1) were evaluated in mung bean (Vigna radiata). Single NPs and their combinations were foliar applied to 45-day old mung bean plants under greenhouse conditions. In each pot, a total volume of 100 mL of NPs suspension was sprayed on the plants shoot in two steps and one-week interval. After 94 days of growth, membrane degradation, antioxidant activity, photosynthetic pigments, and dry matter accumulation were assessed. At 250 and 500 mg CeO₂-NPs L^-1, there was partial increase of dry matter, stimulated activity of antioxidant enzymes (p ≤ 0.05), and reactive oxygen species (ROS). However, at 1000 mg L^-1, CeO₂-NPs caused strong accumulation of ROS (p ≤ 0.05), enlargement of starch granules and swelling of chloroplasts. In addition, at such concentration, there was accumulation of starch granules, reduction of photosynthetic pigments, biological nitrogen fixation, chlorosis, and a significant retardation in plant growth, compared with control, (p ≤ 0.05). Combination of Se-NPs (25 and 50 mg L^-1) with 250 mg L^-1 of CeO₂ NPs decreased hydrogen peroxide, improved CAT, Chla, Chlb, and increased dry matter (p ≤ 0.05). At 1000 mg CeO₂ NPs L^-1, foliar spray of Se-NPs led to Ce accumulation in the cell wall and increased levels of SOD and proline (p ≤ 0.05). Results showed that 25 and 50 mg Se NPs L^-1 ameliorate the stress of CeO₂ NPs by upregulating photosynthesis pigments, antioxidants, and dry matter accumulation. Therefore, depending on the CeO₂ NPs concentration, the mechanisms of Se NPs in modulating CeO₂ NPs stress varied; low concentrations of Se NPs may strengthen the metabolism of legumes, and protect them against foliar toxicity of CeO₂ NPs in semi-arid ecosystems.

Recent Advances in Metal-Based Nanoparticle-Mediated Biological Effects in Arabidopsis thaliana: A Mini Review

The widespread application of metal-based nanoparticles (MNPs) has prompted great interest in nano-biosafety. Consequently, as more and more MNPs are released into the environment and eventually sink into the soil, plants, as an essential component of the ecosystem, are at greater risk of exposure and response to these MNPs. Therefore, to understand the potential impact of nanoparticles on the environment, their effects should be thoroughly investigated. Arabidopsis (Arabidopsis thaliana L.) is an ideal model plant for studying the impact of environmental stress on plants’ growth and development because the ways in which Arabidopsis adapt to these stresses resemble those of many plants, and therefore, conclusions obtained from these scientific studies have often been used as the universal reference for other plants. This study reviewed the main findings of present-day interactions between MNPs and Arabidopsis thaliana from plant internalization to phytotoxic effects to reveal the mechanisms by which nanomaterials affect plant growth and development. We also analyzed the remaining unsolved problems in this field and provide a perspective for future research directions.

Foliar Application of Cerium Oxide-Salicylic Acid Nanoparticles (CeO2:SA Nanoparticles) Influences the Growth and Physiological Responses of Portulaca oleracea L. under Salinity

In the present study, the effects of foliar application of salicylic acid (100 μM), cerium oxide (50 mg L⁻¹), and cerium oxide:salicylic acid nanoparticles (CeO₂: SA-nanoparticles, 50 mg L⁻¹ + 100 μM) on the growth and physiological responses of purslane (Portulaca oleracea L.) were examined in non-saline and saline conditions (50 and 100 mM NaCl salinity). Foliar applications mitigated salinity-induced adverse effects, and the highest plant height and N, P, Mg, and Mn content were recorded in the variant with non-saline × foliar use of CeO₂: SA-nanoparticles. The highest values of fresh and dry weight were noted in the treatment with no-salinity × foliar use of CeO₂:SA-nanoparticles. The highest number of sub-branches was observed in the foliar treatments with CeO₂-nanoparticles and CeO₂:SA-nanoparticles without salinity stress, while the lowest number was noted in the 100 mM NaCl treatment. Moreover, the foliar application of CeO₂:SA-nanoparticles and cerium-oxide nanoparticles improved the total soluble solid content, K, Fe, Zn, Ca, chlorophyll a, and oil yield in the plants. The salinity of 0 and 50 mM increased the K content, 1000-seed weight, total soluble solid content, and chlorophyll b content. The use of 100 mM NaCl with no-foliar spray increased the malondialdehyde, Na, and H₂O₂ content and the Na⁺/K⁺ ratio. No-salinity and 50 mM NaCl × CeO₂: SA-nanoparticle interactions improved the anthocyanin content in plants. The phenolic content was influenced by NaCl₁₀₀ and the foliar use of CeO₂:SA-nanoparticles. The study revealed that the foliar treatment with CeO₂:SA-nanoparticles alleviated the side effects of salinity by improving the physiological responses and growth-related traits of purslane plants.

Soil and foliar exposure of soybean (Glycine max) to Cu: Nanoparticle coating-dependent plant responses

In this study, we investigated the effects of citric acid (CA) coated copper oxide nanoparticles (CuO NPs) and their application method (foliar or soil exposure) on the growth and physiology of soybean (Glycine max). After nanomaterials exposure via foliar or soil application, Cu concentration was elevated in the roots, leaves, stem, pod, and seeds; distribution varied by plant organ and surface coating. Foliar application of CuO NPs at 300 mg/L and CuO-CA NPs at 75 mg/L increased soybean yield by 169.5% and 170.1%, respectively. In contrast, foliar and soil exposure to ionic Cu with all treatments (75 and 300 mg/L) had no impact on yield. Additionally, CuO-CA NPs at 300 mg/L significantly decreased Cu concentration in seeds by 46.7%, compared to control, and by 44.7%, compared to equivalent concentration of CuO NPs. Based on the total Cu concentration, CuO NPs appeared to be more accessible for plant uptake, compared to CuO-CA NPs, inducing a decrease in protein content by 56.3% and inhibiting plant height by 27.9% at 300 mg/kg under soil exposure. The translocation of Cu from leaf to root and from the root to leaf through the xylem was imaged by two-photon microscopy. The findings indicate that citric acid coating reduced CuO NPs toxicity in soybean, demonstrating that surface modification may change the toxic properties of NPs. This research provides direct evidence for the positive effects of CuO-CA NPs on soybean, including accumulation and in planta transfer of the particles, and provides important information when assessing the risk and the benefits of NP use in food safety and security.

Integrated proteome and lipidome analysis of naturally aged safflower seeds varying in vitality

Seed ageing has an important effect on germination and productivity. During natural ageing, seed vigour decreases rapidly but, to date, the molecular mechanisms underlying this decrease have not been fully elucidated. Using omics, some of the details regarding seed vigour decline during natural ageing might be elucidated through integrated analysis. Safflower seed germination and physio-biochemical changes during natural ageing (stored for 4, 16 and 28 months) were determined. Proteome and lipidome profiling during natural seed ageing was performed, and the differentially expressed proteins and lipid metabolite species analysed. The surface and internal structures of cotyledons were observed. An integrating analysis of the proteome and lipidome was also carried out. Natural seed ageing significantly decreased safflower seed germination and vigour. 4,184 proteins and 1,193 lipids were quantified, both of which show huge differences among the different naturally aged seeds. The surface of the cotyledons collapsed and cracked, and the oil bodies become looser during natural ageing. The total content of DAG and PA increased, while the content of TAG and PL (PC, PE, PS, PI and PL) significantly decreased during seeds ageing. Two lipase genes (HH-026818-RA and HH-025320) likely participated in this degradation of lipids. We conclude that the enzymes that participate in glycerolipid metabolism and fatty acid degradation probably lead to the degradation of oil bodies (TAG) and membrane lipids (PC, PE, PS, PI, PG) and, ultimately, destroy the structure, causing a decline in seed vigour during natural seed ageing.

Cross-examination of engineered nanomaterials in crop production: Application and related implications

The review presents the current knowledge on the development and implementation of nanotechnology in crop production, giving particular attention to potential opportunities and challenges of the use of nano-sensors, nano-pesticides, and nano-fertilizers. Due to the size-dependent properties, e.g. high reactivity, targeted and controlled delivery of active ingredients, engineered nanomaterials (ENMs) are expected to be more efficient agrochemicals than conventional agents. Growing production and usage of ENMs result in the spread of ENMs in the environment. Because plants constitute an important component of the agri-ecosystem, they are subjected to the ENMs activity. A number of studies have confirmed the uptake and translocation of ENMs by plants as well as their positive/negative effects on plants. Here, these endpoints are briefly summarized to show the diversity of plant responses to ENMs. The review includes a detailed molecular analysis of ENMs-plant interactions. The transcriptomics, proteomics and metabolomics tools have been very recently employed to explore ENMs-induced effects in planta. The omics approach allows a comprehensive understanding of the specific machinery of ENMs occurring at the molecular level. The summary of data will be valuable in defining future studies on the ENMs-plant system, which is crucial for developing a suitable strategy for the ENMs usage.

Effects of Metal Nanoparticles and Other Preparative Materials in the Environment on Plants: From the Perspective of Improving Secondary Metabolites

The influence of preparation material residues in wastewater and soil on plants has been paid more and more attention by researchers. Secondary metabolites play an important role in the application of plants. It was found that nanomaterials can increase the content of plant secondary metabolites in addition to their role in pharmaceutical preparations. For example, 800 mg/kg copper oxide nanoparticles (NPs) increased the content of p-coumaric acid in cucumber by 225 times. Nanoparticles can cause oxidative stress in plants, increase signal molecule, and upregulate the synthase gene expression, increasing the content of secondary metabolites. The increase of components such as polyphenols and total flavonoids may be related to oxidative stress. This paper reviews the application and mechanism of metal nanomaterials (Ag-NP, ZnO-NP, CeO₂-NP, Cds-NP, Mn-NP, CuO-NP) in promoting the synthesis of secondary metabolites from plants. In addition, the effects of some other preparative materials (cyclodextrins and immobilized molds) on plant secondary metabolites are also involved. Finally, possible future research is discussed.

Aerially Applied Zinc Oxide Nanoparticle Affects Reproductive Components and Seed Quality in Fully Grown Bean Plants (Phaseolus vulgaris L.)

The development of reproductive components in plant species is susceptible to environmental stresses. The extensive application of zinc oxide nanoparticles (nZnO) in various agro-industrial processes has jeopardized the performance and functionality of plants. To understand the response of the developmental (gametogenesis and sporogenesis) processes to nanoparticles (NPs) exposure, the aerial application of nZnO and their ionic counterpart of ZnSO₄ at four different levels were examined on bean plants (Phaseolus vulgaris) before the flowering stage. To evaluate the mentioned processes, briefly, flowers in multiple sizes were fixed in paraffin, followed by sectioning and optical analysis. The possibility of alteration in reproductive cells was thoroughly analyzed using both light and electron microscopes. Overall, our results revealed the histological defects in male and female reproductive systems of mature plants depend on NPs levels. Furthermore, NPs caused tapetum abnormalities, aberrations in carbohydrate accumulation, and apoptosis. The nZnO induced abnormal alterations right after meiosis and partly hindered the microspore development, leading to infertile pollens. The seed yield and dry weight were reduced to 70 and 82% at 2,000 mg L^-1 nZnO foliar exposure, respectively. The sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis pattern showed the increased expression of two proteins at the molecular weight of 28 and 42 kDa at various concentrations of nZnO and ZnSO₄. Overall, our results provided novel insights into the negative effect of nano-scaled Zn on the differential mechanism involved in the reproductive stage of the plants compared with salt form.

Graphene-triphenyl phosphate (TPP) co-exposure in the marine environment: Interference with metabolism and immune regulation in mussel Mytilus galloprovincialis

Both immune regulation and endocrine systems are great challenges to marine organisms, and effective protocols for determining these adverse outcome pathways are limited, especially in vivo. The increasing usage of graphene nanomaterials can lead to the frequent exposure to marine organisms. Triphenyl phosphate (TPP), an organophosphate flame retardant, is frequently detected in natural environments. In this study, the combined toxic effects of co-exposure to graphene and TPP was investigated in Mytilus galloprovincialis using computational toxicology and multi-omics technology. Noticeably, graphene could disturb the membrane stability and increase the tissue accumulation of TPP. The adsorption behavior of TPP on graphene could inhibit the surface activity of graphene. In the digestive gland, transcriptomics analysis revealed the down-regulated genes in graphene + TPP treatment, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH), sorbitol dehydrogenase (SORD), glutathione s-transferase mu 3 (GSTM3) and 4-aminobutyrate aminotransferase (ABAT), were mainly associated with oxidative stress and energy metabolism. Moreover, metabolic responses indicated that graphene + TPP could cause disturbances in energy metabolism and osmotic regulation marked by differentially altered ATP, glucose and taurine in mussels. These data underline the need for further knowledge on the potential interactions of nanomaterials with existing contaminants in marine organisms.

Metabolomic Response of Early-Stage Wheat (Triticum aestivum) to Surfactant-Aided Foliar Application of Copper Hydroxide and Molybdenum Trioxide Nanoparticles

Surfactants are commonly used in foliar applications to enhance interactions of active ingredients with plant leaves. We employed metabolomics to understand the effects of TritonTM X-100 surfactant (SA) and nanomaterials (NMs) on wheat (Triticum aestivum) at the molecular level. Leaves of three-week-old wheat seedlings were exposed to deionized water (DI), surfactant solution (SA), NMs-surfactant suspensions (Cu(OH)2 NMs and MoO3 NMs), and ionic-surfactant solutions (Cu IONs and Mo IONs). Wheat leaves and roots were evaluated via physiological, nutrient distribution, and targeted metabolomics analyses. SA had no impact on plant physiological parameters, however, 30+ dysregulated metabolites and 15+ perturbed metabolomic pathways were identified in wheat leaves and roots. Cu(OH)2 NMs resulted in an accumulation of 649.8 μg/g Cu in leaves; even with minimal Cu translocation, levels of 27 metabolites were significantly changed in roots. Due to the low dissolution of Cu(OH)2 NMs in SA, the low concentration of Cu IONs induced minimal plant response. In contrast, given the substantial dissolution of MoO3 NMs (35.8%), the corresponding high levels of Mo IONs resulted in significant metabolite reprogramming (30+ metabolites dysregulated). Aspartic acid, proline, chlorogenic acid, adenosine, ascorbic acid, phenylalanine, and lysine were significantly upregulated for MoO3 NMs, yet downregulated under Mo IONs condition. Surprisingly, Cu(OH)2 NMs stimulated wheat plant tissues more than MoO3 NMs. The glyoxylate/dicarboxylate metabolism (in leaves) and valine/leucine/isoleucine biosynthesis (in roots) uniquely responded to Cu(OH)2 NMs. Findings from this study provide novel insights on the use of surfactants to enhance the foliar application of nanoagrochemicals.

The Differences between the Effects of a Nanoformulation and a Conventional Form of Atrazine to Lettuce: Physiological Responses, Defense Mechanisms, and Nutrient Displacement

The rapid development of nanotechnology influences the developments within the agro-sector. An example is provided by the production of nanoenabled pesticides with the intention to optimize the efficiency of the pesticides. At the same time, it is important to collect information on the unintended and unwanted adverse effects of emerging nanopesticides on nontarget plants. Currently, this information is limited. In the present study, we compared the effects of a nanoformulation of atrazine (NPATZ) and the nonencapsulated atrazine formulation (ATZ) on physiological responses, defense mechanisms, and nutrient displacement in lettuce over time with the applied concentrations ranging from 0.3 to 3 mg atrazine per kg soil. Our results revealed that both NPATZ and ATZ induced significant decreases in plant biomass, chlorophyll content, and protein content. Additionally, exposure to NPATZ and ATZ caused oxidative stress to the lettuce plant and significantly elevated the activities of the tested ROS scavenger enzymes in plant tissues. These results indicate that NPATZ and ATZ cause distinct adverse impacts on lettuce plants. When comparing the adverse effects in plants after exposure to NPATZ and ATZ, no obvious differences in plant biomass and chlorophyll content were observed between NPATZ and ATZ treatments at the same exposure concentration regardless of exposure duration. An enhanced efficiency of the active ingredient of the nanopesticide as compared to the conventional formulation was observed after long-term exposure to the high concentration of NPATZ, as it induced higher impacts on plants in terms of the end points of the contents of protein, superoxide anion (O2̇-), and MDA, and the activities of stress-related enzymes as compared to the same concentration of ATZ. Furthermore, exposure to both NPATZ and ATZ disrupted the uptake of mineral nutrients in plants, and the differences in the displacement of nutrients between the NPATZ and ATZ treatments depended on the element type, plant organ, exposure concentration, and time. Overall, the application dose of a nanopesticide should balance their increased herbicidal efficiency with the long-term adverse effects in order to maximize the desired impact while minimizing adverse impacts; only then will we be able to understand the potential impact of nanopesticides on the environment.

Differential responses of maize (Zea mays) at the physiological, biomolecular, and nutrient levels when cultivated in the presence of nano or bulk ZnO or CuO or Zn2+ or Cu2+ ions

Expanding applications of metal-based nanoparticles (NPs) in industry and agriculture have influenced agro-ecosystems. However, relatively little is known about the bioaccumulation, distribution, and phytotoxicity of ZnO-NPs, CuO-NPs, ZnO-bulk, CuO-bulk, Zn²⁺, or Cu²⁺ in maize. Plants were exposed to 0.05-2 mg ml^-1 or g^-1 of six tested materials in agar (7 days) in hydroponic medium (20 days), or sandy-clay-loam soil (20 or 40 days). Seed germination, emergence and lengths of plumules, principal and seminal roots were significantly inhibited by ZnO-NPs, CuO-NPs, Zn²⁺, and Cu²⁺. Toxicity was more pronounced in hydroponic culture than in soil, and perceptible alterations in biomolecules were evident. ICP-MS analysis exhibited progressive uptake of metals while morphological, elemental, and surface/deeper scanning showed translocation and distribution of NPs in tissues. Tested materials induced enhanced superoxide radical production, lipid peroxidation, and antioxidant enzymes and proline levels. Exposure significantly reduced P-accumulation, photosynthesis, and protein production. Zn²⁺ and Cu²⁺ were found to be more toxic than NPs. Compared to 20 days exposure in soil, toxicity slightly increased after 40 days. ZnO-NPs and CuO-NPs increased apoptotic sub-G1 population by 22.4% and 38%, respectively. These results provide a better understanding of the mechanistic aspects responsible for the nanotoxicities of ZnO- and CuO-NPs in maize.

Recent insights into the impact, fate and transport of cerium oxide nanoparticles in the plant-soil continuum

The advent of the nanotechnology era offers a unique opportunity for sustainable agriculture provided that the exposure and toxicity are adequately assessed and properly controlled. The global production and application of cerium oxide nanoparticles (CeO₂-NPs) in various industrial sectors have tremendously increased. Most of the nanoparticles end up in water and soil where they interact with soil microorganisms and plants. Investigating the uptake, translocation and accumulation of CeO₂-NPs is critical for its safe application in agriculture. Plant uptake of CeO₂-NPs may lead to their accumulation in different plant tissues and interference with key metabolic processes of plants. Soil microbes can also be affected by increasing CeO₂-NPs in soil, leading to changes in the physiology and enzymatic activity of soil microorganisms. The interactions between CeO₂-NPs, microbes and plants in the agricultural system need systemic research in ecologically relevant conditions. In the present review, The uptake pathways and in-planta translocation of CeO₂-NPs,and their impact on plant morphology, nutritional values, antioxidant enzymes and molecular determinants are presented. The role of CeO₂-NPs in modifying soil microbial community in plant rhizosphere is also discussed. Overall, the review aims to provide a comprehensive account on the behaviour of CeO₂-NPs in soil-plant systems and their potential impacts on the soil microbial community and plant health.

Exogenous application of ZnO nanoparticles and ZnSO4 distinctly influence the metabolic response in Phaseolus vulgaris L

Nanomaterials-mediated contamination (including the highly reactive metal oxides ZnO nanoparticles) is becoming one of the most concerning issues worldwide. In this study, the toxic effects of two chemical species of Zn (ZnO nanoparticles and bulk ZnSO₄) were investigated in bean plants, following either foliar or soil application, at concentrations from 250 to 2000 mg L^-1 using biochemical assays, proteomics and metabolomics. The accumulation of Zn in plant tissues depended on the application type, zinc chemical form and concentration, in turn triggering distinctive morphological, physiological, and redox responses. Bean plants were more sensitive to the foliar than to the soil application, and high concentrations of ZnO NP and bulk ZnSO₄ determined the highest plant growth inhibition and stress symptoms. However, low dosages of ZnSO₄ induced a slight plant growth promotion and better physiological and antioxidative response. Low concentration of Zn leaded to increased activity of stress-related proteins and secondary metabolites with antioxidant capacity, while increasing concentration reached the exhausted phase of the plant stress response, reducing the antioxidant defense system. Such high concentrations increased lipids peroxidation, protein degradation and membranes integrity. Oxidative damage occurred at high concentrations of both chemical species of Zn. Foliar spraying impaired photosynthetic efficiency, while soil applications (especially ZnSO₄) elicited antioxidant metabolites and proteins, and impaired chloroplast-related proteins involved in the electron transport chain and ATP production. Taken together, the results highlighted distinctive and nanoparticles-related toxic effects of ZnO in bean, compared to ionic forms of Zn.

Assessment of Morpho-Physiological and Biochemical Responses of Mercury-Stressed Trigonella foenum-gracum L. to Silver Nanoparticles and Sphingobacterium ginsenosidiumtans Applications

Heavy metals are primarily generated and deposited in the environment, causing phytotoxicity. This work evaluated fenugreek plants’ morpho-physiological and biochemical responses under mercury stress conditions toward Ag nanoparticles and Sphingobacterium ginsenosidiumtans applications. The fabrication of Ag nanoparticles by Thymus vulgaris was monitored and described by UV/Vis analysis, FTIR, and SEM. The effect of mercury on vegetative growth was determined by measuring the root and shoots length, the number and area of leaves, the relative water content, and the weight of the green and dried plants; appraisal of photosynthetic pigments, proline, hydrogen peroxide, and total phenols content were also performed. In addition, the manipulation of Ag nanoparticles, S. ginsenosidiumtans, and their combination were tested for mercury stress. Here, Ag nanoparticles were formed at 420 nm with a uniform cuboid form and size of 85 nm. Interestingly, the gradual suppression of vegetal growth and photosynthetic pigments by mercury, Ag nanoparticles, and S. ginsenosidiumtans were detected; however, carotenoids and anthocyanins were significantly increased. In addition, proline, hydrogen peroxide, and total phenols content were significantly increased because mercury and S. ginsenosidiumtans enhance this increase. Ag nanoparticles achieve higher levels by the combination. Thus, S. ginsenosidiumtans and Ag nanoparticles could have the plausible ability to relieve and combat mercury’s dangerous effects in fenugreek.

Ingestion and effects of cerium oxide nanoparticles on Spodoptera frugiperda (Lepidoptera: Noctuidae)

The objective of this study was to evaluate the biological and nutritional characteristics of Spodoptera frugiperda (Lepidoptera: Noctuidae), an arthropod pest widely distributed in agricultural regions, after exposure to nano-CeO₂ via an artificial diet and to investigate the presence of cerium in the body of this insect through X-ray fluorescence mapping. Nano-CeO₂, micro-CeO₂, and Ce(NO₃)₃ were incorporated into the diet (0.1, 1, 10, and 100 mg of Ce L^-1). Cerium was detected in caterpillars fed with diets containing nano-CeO₂ (1, 10 and 100 mg of Ce L^-1), micro-CeO₂ and Ce(NO₃)₃, and in feces of caterpillars from the first generation fed diets with nano-CeO₂ at 100 mg of Ce L^-1 as well. The results indicate that nano-CeO₂ caused negative effects on S. frugiperda. After it was consumed by the caterpillars, the nano-CeO₂ reduced up to 4.8% of the pupal weight and 60% of egg viability. Unlike what occurred with micro-CeO₂ and Ce(NO₃)₃, nano-CeO₂ negatively affected nutritional parameters of this insect, as consumption rate two times higher, increase of up to 80.8% of relative metabolic rate, reduction of up to 42.3% efficiency of conversion of ingested and 47.2% of digested food, and increase of up to 1.7% of metabolic cost and 8.7% of apparent digestibility. Cerium caused 6.8-16.9% pupal weight reduction in second generation specimens, even without the caterpillars having contact with the cerium via artificial diet. The results show the importance of new ecotoxicological studies with nano-CeO₂ for S. frugiperda in semi-field and field conditions to confirm the toxicity.

Effect of nano cerium oxide on soybean (Glycine max L. Merrill) crop exposed to environmentally relevant concentrations

This study evaluated the uptake and translocation of cerium nanoparticles (CeO2 NPs) and soluble Ce(NO3)3 by soybean plants (Glycine max L. Merrill) under the whole plant life-cycle and relevant environmental concentrations, 0.062 and 0.933 mg kg-1, which represent maximal values for 2017 in agricultural soils and sludge treated soils, respectively. The experiments were carried out using a nutrient solution. Cerium was detected in the soybean roots epidermis and cortex, leaves, and grains, but it neither impaired plant development nor grain yield. The concentration of Ce in the shoot increased as a function of time for plants treated with Ce(NO3)3, while it remained constant for plants treated with CeO2 NPs. It means that CeO2 NPs were absorbed in the same rate as biomass production, which suggests that they are taken up and transported by water mass flow. Single-particle inductively coupled plasma mass spectrometry revealed clusters of CeO2 NPs in leaves of plants treated with 25 nm CeO2 NPs (ca. 30-45 nm). The reprecipitation of soluble cerium from Ce(NO3)3 within the plant was not confirmed. Finally, bioconcentration factors above one were found for the lowest concentrated treatments. Since soybean is a widespread source of protein for animals, we draw attention to the importance of evaluating the effects of Ce entrance in the food chain and its possible biomagnification.