Innovative approach to sunlight activated biofungicides for strawberry crop protection: ZnO nanoparticles

The polysaccharide-based nanoemulsions: Preparation, mechanism, and application in food preservation-A review

The stability and bioavailability of antioxidant, antibacterial, and other bioactive substances could be improved through nanoemulsion systems, as a result, nanoemulsion technology has become popular in food preservation. Polysaccharides are green polymers, their renewability, richness, safety, and functionality determine broad application prospects. Polysaccharide-based nanoemulsion coatings with good waterproofness, and mechanical and biological properties are found to effectively prevent or delay water loss, respiration, gas exchange, and microbial corruption of fruits, vegetables, and meat products, and they will be an important innovative technology for sustainable development in the future. The structural and functional properties of polysaccharides that could stabilize nanoemulsions have been discussed, and the preparation methods, physicochemical properties, stability, and formation mechanism of nanoemulsions have been summarized in this review. In addition, the preparation methods of polysaccharide-based nanoemulsion coatings are summarized, the application and preservation mechanisms in fruits, vegetables, and meat products have been introduced, and future perspectives have been discussed. At present, the related researches mainly focus on the bactericidal activity and the sensory quality of food products, while the in-depth research is unclear, this review provides ideas for the subsequent research on polysaccharide-based nanoemulsions for food preservation.

Enhancing postharvest food safety: the essential role of non-thermal technologies in combating fungal contamination and mycotoxins

During the production and storage of agricultural products, molds frequently occur as contaminants that can produce a wide range of secondary metabolites, the most important of which are mycotoxins. To solve these problems, the industry uses various methods, products and processes. This review examines the latest advances in novel non-thermal technologies for post-harvest inactivation of filamentous fungi and reduction of mycotoxins. These technologies include high pressure processes (HPP), ozone treatment, UV light, blue light, pulsed light, pulsed electric fields (PEF), cold atmospheric plasma (CAP), electron beams, ultrasound (US) and nanoparticles. Using data from previous studies, this review provides an overview of the primary mechanisms of action and recent results obtained using these technologies and emphasizes the limitations and challenges associated with each technology. The innovative non-thermal methods discussed here have been shown to be safe and efficient tools for reducing food mold contamination and infection. However, the effectiveness of these technologies is highly dependent on the fungal species and the structural characteristics of the mycotoxins. New findings related to the inactivation of fungi and mycotoxins underline that for a successful application it is essential to carefully determine and optimize certain key parameters in order to achieve satisfactory results. Finally, this review highlights and discusses future directions for non-thermal technologies. It emphasizes that they meet consumer demand for clean and safe food without compromising nutritional and sensory qualities.

Nano-sized metal oxide fertilizers for sustainable agriculture: balancing benefits, risks, and risk management strategies

This critical review comprehensively analyses nano-sized metal oxide fertilizers (NMOFs) and their transformative potential in sustainable agriculture. It examines the characteristics and benefits of different NMOFs, such as zinc, copper, iron, magnesium, manganese, nickel, calcium, titanium, cerium, and silicon oxide nanoparticles. NMOFs offer unique advantages such as increased reactivity, controlled-release mechanisms, and targeted nutrient delivery to address micronutrient deficiencies, enhance crop resilience, and improve nutrient efficiency. The review underscores the essential role of micronutrients in plant metabolism, crop growth, and ecosystem health, highlighting their importance alongside macronutrients. NMOFs present significant benefits over traditional fertilizers, including enhanced plant uptake, reduced nutrient losses, and decreased environmental impact. However, the review also critically examines potential risks associated with NMOFs, such as nanoparticle toxicity and environmental persistence. A comparative analysis of different metal types used in nanofertilizers is provided, detailing their primary advantages and potential drawbacks. The review emphasizes the need for cautious management of NMOFs to ensure their safe and effective use in agriculture. It calls for comprehensive research to understand the long-term effects of NMOFs on plant health, soil ecosystems, and human health. By integrating insights from material science, plant biology, and environmental science, this review offers a holistic perspective on the potential of NMOFs to address global food security challenges amid resource constraints and climate change. The study concludes by outlining future research directions and advocating for interdisciplinary collaboration to advance sustainable agricultural practices and optimize the benefits of NMOFs.

Determination of antifungal efficacy and phytotoxicity of a unique silica coated porous zinc oxide nanocomposite medium for slow-release agrochemicals

AIMS

In this study, the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) were analyzed as this nanocomposite was observed to be a suitable platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well.

METHODS AND RESULTS

Loading and release kinetics of tricyclazole, a potent fungicide, were analyzed by measuring surface area (SBET) using Brunauer-Emmett-Teller (BET) isotherm and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy. Nanoparticle mediated elevation of reactive oxygen species (ROS) in fungal samples was detected by analyzing the levels of superoxide dismutase, catalase, thiol content, lipid peroxidation, and by 2,7-dichlorofluorescin diacetate assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of fluorescein isothiocyanate tagged SZNP within the plant tissue.

CONCLUSIONS

ZNP had superior antifungal efficacy than SZNP and caused the generation of more ROS in the fungal samples. Even then, SZNP was preferred as an agrochemical delivery vehicle because, unlike ZNP alone, it was not toxic to plant system. Moreover, as silica in nanoform is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.

Metal-Organic Framework-Enabled Sustainable Agrotechnologies: An Overview of Fundamentals and Agricultural Applications

With aggravated abiotic and biotic stresses from increasing climate change, metal-organic frameworks (MOFs) have emerged as versatile toolboxes for developing environmentally friendly agrotechnologies aligned with agricultural practices and safety. Herein, we have explored MOF-based agrotechnologies, focusing on their intrinsic properties, such as structural and catalytic characteristics. Briefly, MOFs possess a sponge-like porous structure that can be easily stimulated by the external environment, facilitating the controlled release of agrochemicals, thus enabling precise delivery of agrochemicals. Additionally, MOFs offer the ability to remove or degrade certain pollutants by capturing them within their pores, facilitating the development of MOF-based remediation technologies for agricultural environments. Furthermore, the metal-organic hybrid nature of MOFs grants them abundant catalytic activities, encompassing photocatalysis, enzyme-mimicking catalysis, and electrocatalysis, allowing for the integration of MOFs into degradation and sensing agrotechnologies. Finally, the future challenges that MOFs face in agrotechnologies were proposed to promote the development of sustainable agriculture practices.

Bacillus safensis filtrate-based ZnO nanoparticles control black heart rot disease of apricot fruits by maintaining its soluble sugars and carotenoids

Black heart rot is a serious disease of apricot and it has been reported to be caused by Alternaria solani, around the world. The present research was designed to control this disastrous disease using zinc oxide nanoparticles (b-ZnO NPs). These NPs were synthesized in the filtrate of a useful bacterium (Bacillus safensis) and applied to control black heart rot of apricot. After synthesis, the reduction of b-ZnO NPs was confirmed by UV-visible spectroscopy, at 330 nm. Fourier transform infrared (FTIR) spectra ensured the presence of multiple functional groups (alcohols, phenols, carboxylic acids, nitro compounds and amines) on the surface of b-ZnO NPs. X-Ray diffraction (XRD) analysis elucidated their average size (18 nm) while scanning electron microscopy (SEM) micrograph described the spherical shape of b-ZnO NPs. The synthesized b-ZnO NPs were applied in four different concentrations (0.25 mg/ml, 0.50 mg/ml, 0.75 mg/ml, 1.0 mg/ml) under both in vitro and in vivo conditions. These NPs were very efficient in inhibiting mycelial growth (85.1%) of A. solani at 0.75 mg/ml concentration of NPs, in vitro. Same concentration also performed best, in vivo, and significantly reduced disease incidence (by 67%) on self-inoculated apricot fruit. Apart from this, application of b-ZnO NPs helped apricot fruit to maintain its quality under fungal-stress conditions. The decay of apricot fruit was reduced and they maintained greater firmness and higher weight. Moreover, b-ZnO NPs treated fruits controlled black heart rot disease by maintaining higher contents of ascorbic acid, soluble sugars and carotenoids. These b-ZnO NPs were produced in powder form for their easy carriage to the farmers' fields.

Improving RNA-based crop protection through nanotechnology and insights from cross-kingdom RNA trafficking

Spray-induced gene silencing (SIGS) is a powerful and eco-friendly method for crop protection. Based off the discovery of RNA uptake ability in many fungal pathogens, the application of exogenous RNAs targeting pathogen/pest genes results in gene silencing and infection inhibition. However, SIGS remains hindered by the rapid degradation of RNA in the environment. As extracellular vesicles are used by plants, animals, and microbes in nature to transport RNAs for cross-kingdom/species RNA interference between hosts and microbes/pests, nanovesicles and other nanoparticles have been used to prevent RNA degradation. Efforts examining the effect of nanoparticles on RNA stability and internalization have identified key attributes that can inform better nanocarrier designs for SIGS. Understanding sRNA biogenesis, cross-kingdom/species RNAi, and how plants and pathogens/pests naturally interact are paramount for the design of SIGS strategies. Here, we focus on nanotechnology advancements for the engineering of innovative RNA-based disease control strategies against eukaryotic pathogens and pests.

Alleviation of salinity stress in zinc oxide nanoparticle-treated Lagenaria siceraria L. by modulation of physiochemical attributes, enzymatic and non-enzymatic antioxidative system

Salt stress is a major abiotic stress that affects the world's agricultural soils and crop yield, the system that ensures food production. In the present study, three different concentrations of zinc oxide nanoparticles (250, 500 and 750ZnONPsmg L-1 ) were applied by soil drenching. The treatments aimed to improve the phytochemical characteristics of Lagenaria siceraria L. (bottle gourd) by lowering the oxidative stress brought on by salinity stress (200ppm NaF). Green synthesised ZnO NPs were prepared, having hexagonal and spherical shapes and sizes 16-35nm. Salt stress reduced fresh and dry biomass of plants and improved production of proline. ZnO NPs improved antioxidant response by enhancing catalase, ascorbate peroxidase, superoxide dismutase and peroxidase activities, and protecting cellular structures by eliminating free radicals and reactive oxygen species. The 500mg L-1 ZnO NPs treatment improved total chlorophyll (31%), total soluble sugars (23%) and maintained the gas exchange parameters under salt stress. This treatment also enhanced the biosynthesis of osmotic regulators (proline) by 19%, Na+ by 22% and Zn2+ by 17%, assisting mitigation of salt stress-mediated toxicity in plants. This study demonstrates that ZnO NP-treated seedlings show improved growth attributes, suggesting that ZnO NPs could be advantageous for L. siceraria cultivation in salt polluted areas and could be utilised in place of conventional Zn fertiliser for better crop yield.

Eco-sustainable coatings based on chitosan, pectin, and lemon essential oil nanoemulsion and their effect on strawberry preservation

Films and coatings manufactured with bio-based renewable materials, such as biopolymers and essential oils, could be a sustainable and eco-friendly alternative for protecting and preserving agricultural products. In this work, we developed films and coatings from pectin and chitosan to protect strawberries (Fragaria x ananassa Duch.) from spoilage and microbial contamination. We developed three coatings containing equal amounts of glycerol and Sicilian lemon essential oil (LEO) nanoemulsion. We identified seventeen chemicals from LEO by GC-MS chromatogram, including d-limonene, α-Pinene, β-Pinene, and γ-Terpinene. The pectin and chitosan coatings were further characterized using different physicochemical, mechanical, and biological methods. The films demonstrated satisfactory results in strength and elongation at the perforation as fruit packaging. In addition, the coatings did not influence the weight and firmness of the strawberry pulps. We observed that 100 % essential oil was released in 1440 min resulting from the erosion process. Also, the oil preserved the chemical stability of the films. Antioxidant activity (AA), measured by Electron Paramagnetic Resonance (EPR), showed that the coatings loaded with 2 % LEO nanoemulsion (PC + oil) showed that almost 50 % of AA from LEO nanoemulsion was preserved. The chitosan and the pectin-chitosan coatings (PC + oil) inhibited filamentous fungi and yeast contaminations in strawberries for at least 14 days, showing a relationship between the AA and antimicrobial results.

Deciphering the fertilizing and disease suppression potential of phytofabricated zinc oxide nanoparticles on Brassicajuncea

Every year 30-50% of crops suffer from fungal and bacterial diseases. Use of various chemically synthesized fungicides and bactericides make the soil environment more toxic and harmful to the plant health. Therefore, there is need to find non-toxic and cost effective alternative against plant pathogen. In recent years, nanotechnology has got attention because of its wide application in different areas of agriculture. Various nanoparticles have been used in agriculture for their fertilizing and antimicrobial potential. Among them zinc oxide nanoparticles (ZnO NPs) have gained the attention of agriculturists as zinc is an essential micronutrient for plants. Antifungal activity of Tb-ZnO NPs (Terminalia bellerica synthesized zinc oxide nanoparticles) against Alternaria brassicae causative agent of blight disease in Brassica juncea has been reported in our previous study. To use Tb-ZnO NPs as nanofungicides and simultaneously as nanofertilizers, the doses of Tb-ZnO NPs beneficial to the Brassica juncea crop is need to be known. Therefore, experiment has been designed to see the protective and curative potential of Tb-ZnO NPs in alluvial and calcareous soil. Biochemical constituents and stress enzymes analysis has shown significant potential of Tb-ZnO NPs at 200 ppm concentration in alleviating the stress caused by A. brassicae by modulating the photosynthetic, biochemical and enzymatic characteristics. Growth parameter analysis confirmed the role of Tb-ZnO NPs in increasing root and shoot length of B. juncea. Yield component such as seed number, seed weight and oil content of B. juncea crop also has been increased. There was one-fold increase in oil content of B. juncea as compared to control. Maximum percent disease control was found to be 70% in alluvial soil (protective method) grown plants. Therefore, present study supports the hypothesis of a relationship between nutrients and disease suppression.

Fungal small RNAs ride in extracellular vesicles to enter plant cells through clathrin-mediated endocytosis

Small RNAs (sRNAs) of the fungal pathogen Botrytis cinerea can enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate that B. cinerea utilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). The B. cinerea tetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerous Arabidopsis clathrin-coated vesicles (CCVs) around B. cinerea infection sites and the colocalization of B. cinerea EV marker BcPLS1 and Arabidopsis CLATHRIN LIGHT CHAIN 1, one of the core components of CCV. Meanwhile, BcPLS1 and the B. cinerea-secreted sRNAs are detected in purified CCVs after infection. Arabidopsis knockout mutants and inducible dominant-negative mutants of key components of the CME pathway exhibit increased resistance to B. cinerea infection. Furthermore, Bc-sRNA loading into Arabidopsis AGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME.

Fungal small RNAs ride in extracellular vesicles to enter plant cells through clathrin-mediated endocytosis

Small RNAs (sRNAs) of the fungal pathogen Botrytis cinerea can enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate that B. cinerea utilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). The B. cinerea tetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerous Arabidopsis clathrin-coated vesicles (CCVs) around B. cinerea infection sites and the colocalization of B. cinerea EV marker BcPLS1 and Arabidopsis CLATHRIN LIGHT CHAIN 1, one of the core components of CCV. Meanwhile, BcPLS1 and the B. cinerea-secreted sRNAs are detected in purified CCVs after infection. Arabidopsis knockout mutants and inducible dominant-negative mutants of key components of CME pathway exhibit increased resistance to B. cinerea infection. Furthermore, Bc-sRNA loading into Arabidopsis AGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME.

Engineered Metal Oxide Nanoparticles as Fungicides for Plant Disease Control

Metal oxide nanoparticles are considered to be good alternatives as fungicides for plant disease control. To date, numerous metal oxide nanoparticles have been produced and evaluated as promising antifungal agents. Consequently, a detailed and critical review on the use of mono-, bi-, and tri-metal oxide nanoparticles for controlling phytopathogenic fungi is presented. Among the studied metal oxide nanoparticles, mono-metal oxide nanoparticles-particularly ZnO nanoparticles, followed by CuO nanoparticles -are the most investigated for controlling phytopathogenic fungi. Limited studies have investigated the use of bi- and tri-metal oxide nanoparticles for controlling phytopathogenic fungi. Therefore, more studies on these nanoparticles are required. Most of the evaluations have been carried out under in vitro conditions. Thus, it is necessary to develop more detailed studies under in vivo conditions. Interestingly, biological synthesis of nanoparticles has been established as a good alternative to produce metal oxide nanoparticles for controlling phytopathogenic fungi. Although there have been great advances in the use of metal oxide nanoparticles as novel antifungal agents for sustainable agriculture, there are still areas that require further improvement.

Plant-ZnO nanoparticles interaction: An approach to improve guinea grass (Panicum maximum) productivity and evaluation of the impacts of its ingestion by freshwater teleost fish

We aimed to evaluate the possible effects of the application of zinc oxide nanoparticles [ZnO NPs; 68.96 ± 33.71 nm; at 100 and 500 mg/kg in a soil mixture of the Typic Dystrophic Red Latosol type and sand (2:1 ratio)] in the cultivation of Panicum maximum (until 125 days), using different biomarkers in addition to evaluating the uptake of Zn by the plants. Furthermore, we assessed the possible transfer of ZnO NPs from P. maximum leaves to zebrafish and their potential. Plants cultivated in substrates with ZnO NPs at 500 mg/kg showed reduced germination rate and growth. However, at 100 mg/kg, plants showed higher biomass and productivity, associated with higher Zn uptake, without inducing oxidative and nitrosative stress. Zinc content in zebrafish was not associated with ingesting leaves of P. maximum cultivated in substrate containing ZnCl₂ or ZnO NPs or with genotoxic, mutagenic, and biochemical effects. In conclusion, ZnO NPs (at 100 mg/kg) are promising in the cultivation of P. maximum, and their ingestion by zebrafish did not cause changes in the evaluated biomarkers. However, we recommend that studies with other animal models be conducted to comprehensively assess the ecotoxicological hazard associated with applying ZnO NPs in soil.

Potential ecotoxicity of substrate-enriched zinc oxide nanoparticles to Physalaemus cuvieri tadpoles

Although the ecotoxicological effects of ZnO nanoparticles (ZnO NPs) have already been reported in different taxa, little is known about their impacts on amphibians. Thus, we aimed to evaluate the potential effects of exposure of Physalaemus cuvieri tadpoles to substrates enriched with ZnO NPs (and with its ionic counterpart, Zn+2, ZnCl2 - both at 100 mg/kg) previously used in the cultivation of Panicum maximum (Guinea grass). We showed that although exposure for 21 days did not impact the survival, growth, and development of tadpoles, we noted an increase in the frequency of erythrocyte nuclear abnormalities in the "ZnCl2" and "ZnONP" groups, which was associated with suppression of antioxidant activity in the animals (inferred by SOD and CAT activity and DPPH free radical scavenging capacity). In the tadpoles of the "ZnONP" group, we also noticed a reduction in creatinine and bilirubin levels, alpha-amylase activity, and an increase in alkaline phosphatase activity. But the treatments did not alter the activity of the enzymes lactate dehydrogenase and gamma-glutamyl-transferase and total protein and carbohydrate levels. On the other hand, we report a cholinesterase and hypotriglyceridemic effect in the "ZnCl2" and "ZnONP" groups. Zn bioaccumulation in animals, from ZnO NPs, from Zn+2 released from them, or both, has been associated with causing these changes. Finally, principal component analysis (PCA) and the values of the "Integrated Biomarker Response" index revealed that the exposure of animals to substrates enriched with ZnO NPs caused more pronounced effects than those attributed to its ionic counterpart. Therefore, our study reinforces the need to consider the environmental risks of using these nanomaterials for agricultural purposes for amphibians.

Nanoparticles as a Promising Strategy to Mitigate Biotic Stress in Agriculture

Nanoparticles are recognized due to their particular physical and chemical properties, which are conferred due to their size, in the range of nanometers. Nanoparticles are recognized for their application in medicine, electronics, and the textile industry, among others, but also in agriculture. The application of nanoparticles as nanofertilizers and biostimulants can help improve growth and crop productivity, and it has therefore been mentioned as an essential tool to control the adverse effects of abiotic stress. However, nanoparticles have also been noted for their exceptional antimicrobial properties. Therefore, this work reviews the state of the art of different nanoparticles that have shown the capacity to control biotic stress in plants. In this regard, metal and metal oxide nanoparticles, polymeric nanoparticles, and others, such as silica nanoparticles, have been described. Moreover, uptake and translocation are covered. Finally, future remarks about the studies on nanoparticles and their beneficial role in biotic stress management are made.

Strawberry Biostimulation: From Mechanisms of Action to Plant Growth and Fruit Quality

The objective of this review is to present a compilation of the application of various biostimulants in strawberry plants. Strawberry cultivation is of great importance worldwide, and, there is currently no review on this topic in the literature. Plant biostimulation consists of using or applying physical, chemical, or biological stimuli that trigger a response-called induction or elicitation-with a positive effect on crop growth, development, and quality. Biostimulation provides tolerance to biotic and abiotic stress, and more absorption and accumulation of nutrients, favoring the metabolism of the plants. The strawberry is a highly appreciated fruit for its high organoleptic and nutraceutical qualities since it is rich in phenolic compounds, vitamins, and minerals, in addition to being a product with high commercial value. This review aims to present an overview of the information on using different biostimulation techniques in strawberries. The information obtained from publications from 2000-2022 is organized according to the biostimulant's physical, chemical, or biological nature. The biochemical or physiological impact on plant productivity, yield, fruit quality, and postharvest life is described for each class of biostimulant. Information gaps are also pointed out, highlighting the topics in which more significant research effort is necessary.

Metallic and non-metallic nanoparticles from plant, animal, and fisheries wastes: potential and valorization for application in agriculture

Global agriculture is facing tremendous challenges due to climate change. The most predominant amongst these challenges are abiotic and biotic stresses caused by increased incidences of temperature extremes, drought, unseasonal flooding, and pathogens. These threats, mostly due to anthropogenic activities, resulted in severe challenges to crop and livestock production leading to substantial economic losses. It is essential to develop environmentally viable and cost-effective green processes to alleviate these stresses in the crops, livestock, and fisheries. The application of nanomaterials in farming practice to minimize nutrient losses, pest management, and enhance stress resistance capacity is of supreme importance. This paper explores innovative methods for synthesizing metallic and non-metallic nanoparticles using plants, animals, and fisheries wastes and their valorization to mitigate abiotic and biotic stresses and input use efficiency in climate-smart and stress-resilient agriculture including crop plants, livestock, and fisheries.

Interaction of the Nanoparticles and Plants in Selective Growth Stages—Usual Effects and Resulting Impact on Usage Perspectives

Nanotechnologies have received tremendous attention since their discovery. The current studies show a high application potential of nanoparticles for plant treatments, where the general properties of nanoparticles such as their lower concentrations for an appropriate effects, the gradual release of nanoparticle-based nutrients or their antimicrobial effect are especially useful. The presented review, after the general introduction, analyzes the mechanisms that are described so far in the uptake and movement of nanoparticles in plants. The following part evaluates the available literature on the application of nanoparticles in the selective growth stage, namely, it compares the observed effect that they have when they are applied to seeds (nanopriming), to seedlings or adult plants. Based on the research that has been carried out, it is evident that the most common beneficial effects of nanopriming are the improved parameters for seed germination, the reduced contamination by plant pathogens and the higher stress tolerance that they generate. In the case of plant treatments, the most common applications are for the purpose of generating protection against plant pathogens, but better growth and better tolerance to stresses are also frequently observed. Hypotheses explaining these observed effects were also mapped, where, e.g., the influence that they have on photosynthesis parameters is described as a frequent growth-improving factor. From the consortium of the used nanoparticles, those that were most frequently applied included the principal components that were derived from zinc, iron, copper and silver. This observation implies that the beneficial effect that nanoparticles have is not necessarily based on the nutritional supply that comes from the used metal ions, as they can induce these beneficial physiological changes in the treated cells by other means. Finally, a critical evaluation of the strengths and weaknesses of the wider use of nanoparticles in practice is presented.

Plants and rhizospheric environment: Affected by zinc oxide nanoparticles (ZnO NPs). A review

Nowadays, there are many critical concerns in the agricultural sector, including reduced productivity of plants due to various environmental factors. Hence, a continuous innovation of existing technologies is necessary. Among the available technologies for sustainable agriculture, nanotechnology is one of the more promising technologies and has a great scope for development in agriculture. Zinc oxide nanoparticles (ZnO NPs) have attracted much attention due to their good properties and can be put into agriculture as nano-fertilizers, nano-growth regulators and nano-pesticides, although much remains to be explored about their mechanisms. Here, we review the literature on the interaction of ZnO NPs with plants through (i) uptake and transport pathways of ZnO NPs in plants. (ii) The mechanisms involved in improving growth, development and resistance. (iii) their effects on the rhizospheric environment. (iv) The toxic effects and mechanisms in plants. Our major conclusions are as follows: (1) they can be absorbed by the plant through the roots and leaves, with subsequent transformation. (2) moderate application can promote plant growth and mitigate stress, while excessive application can produce toxic effects. (3) the effects of them on the rhizospheric environment cannot be ignored. This study may provide a reference for the safe and effective use of ZnO NPs in agricultural production.

Nanotechnological Interventions in Agriculture

Agriculture is an important sector that plays an important role in providing food to both humans and animals. In addition, this sector plays an important role in the world economy. Changes in climatic conditions and biotic and abiotic stresses cause significant damage to agricultural production around the world. Therefore, the development of sustainable agricultural techniques is becoming increasingly important keeping in view the growing population and its demands. Nanotechnology provides important tools to different industrial sectors, and nowadays, the use of nanotechnology is focused on achieving a sustainable agricultural system. Great attention has been given to the development and optimization of nanomaterials and their application in the agriculture sector to improve plant growth and development, plant health and protection and overall performance in terms of morphological and physiological activities. The present communication provides up-to-date information on nanotechnological interventions in the agriculture sector. The present review deals with nanoparticles, their types and the role of nanotechnology in plant growth, development, pathogen detection and crop protection, its role in the delivery of genetic material, plant growth regulators and agrochemicals and its role in genetic engineering. Moreover, the role of nanotechnology in stress management is also discussed. Our aim in this review is to aid researchers to learn quickly how to use plant nanotechnology for improving agricultural production.

Evaluation of the Abilities of Three Kinds of Copper-Based Nanoparticles to Control Kiwifruit Bacterial Canker

Kiwifruit bacterial canker caused by Pseudomonas syringae pv. actinidiae reduces kiwifruit crop yield and quality, leading to economic losses. Unfortunately, few agents for its control are available. We prepared three kinds of copper-based nanoparticles and applied them to control kiwifruit bacterial canker. The successful synthesis of Cu(OH)2 nanowires, Cu3(PO4)2 nanosheets, and Cu4(OH)6Cl2 nanoparticles were confirmed by transmission and scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The minimum bactericidal concentrations (MBCs) of the three nanoparticles were 1.56 μg/mL, which exceeded that of the commercial agent thiodiazole copper (MBC > 100 μg/mL). The imaging results indicate that the nanoparticles could interact with bacterial surfaces and kill bacteria by inducing reactive oxygen species’ accumulation and disrupting cell walls. The protective activities of Cu(OH)2 nanowires and Cu3(PO4)2 nanosheets were 59.8% and 63.2%, respectively, similar to thiodiazole copper (64.4%) and better than the Cu4(OH)6Cl2 nanoparticles (40.2%). The therapeutic activity of Cu4(OH)6Cl2 nanoparticles (67.1%) bested that of Cu(OH)2 nanowires (43.9%), Cu3(PO4)2 nanosheets (56.1%), and thiodiazole copper (53.7%). Their therapeutic and protective activities for control of kiwifruit bacterial canker differed in vivo, which was related to their sizes and morphologies. This study suggests these copper-based nanoparticles as alternatives to conventional bactericides for controlling kiwifruit diseases.

Titanium and Zinc Based Nanomaterials in Agriculture: A Promising Approach to Deal with (A)biotic Stresses?

Abiotic stresses, such as those induced by climatic factors or contaminants, and biotic stresses prompted by phytopathogens and pests inflict tremendous losses in agriculture and are major threats to worldwide food security. In addition, climate changes will exacerbate these factors as well as their negative impact on crops. Drought, salinity, heavy metals, pesticides, and drugs are major environmental problems that need deep attention, and effective and sustainable strategies to mitigate their effects on the environment need to be developed. Besides, sustainable solutions for agrocontrol must be developed as alternatives to conventional agrochemicals. In this sense, nanotechnology offers promising solutions to mitigate environmental stress effects on plants, increasing plant tolerance to the stressor, for the remediation of environmental contaminants, and to protect plants against pathogens. In this review, nano-sized TiO₂ (nTiO₂) and ZnO (nZnO) are scrutinized, and their potential to ameliorate drought, salinity, and xenobiotics effects in plants are emphasized, in addition to their antimicrobial potential for plant disease management. Understanding the level of stress alleviation in plants by these nanomaterials (NM) and relating them with the application conditions/methods is imperative to define the most sustainable and effective approaches to be adopted. Although broad-spectrum reviews exist, this article provides focused information on nTiO₂ and nZnO for improving our understanding of the ameliorative potential that these NM show, addressing the gaps in the literature.

Reduction of Fusarium proliferatum growth and fumonisin accumulation by ZnO nanoparticles both on a maize based medium and irradiated maize grains

This study evaluated the antifungal effect of ZnO nanoparticles (ZnO-NPs) on Fusarium proliferatum growth and fumonisin accumulation both on a maize-based medium (in vitro) and on irradiated maize grains (in situ). The ZnO-NPs were obtained by drop-by-drop synthesis without further thermal treatment and characterized by scanning electronic microscopy/ energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD). SEM analysis showed them as thin flakes of 200 × 200 nm, ~30 nm thickness and its purity were confirmed by XRD. During the in vitro assay ZnO-NPs (0, 0.8; 4, 8 g L^-1) were evaluated at 25 °C during 21 days under darkness or photoperiod incubation (12/12 h light (cold white and black fluorescent lamps)/darkness) to determine its possible photocatalytic influence. Fumonisins were detected by high performance liquid chromatography coupled to mass spectrometry (HPLC- MS/MS). All ZnO-NPs concentrations significantly affected growth rates and FB₁ accumulation by F. proliferatum RCFP 5033 (p < 0.05). Similar reduction of growth and FB₁ (%) was observed at 0.8 and 8 g L^-1 ZnO-NPs under photoperiod or darkness incubation. FB₁ reduction was observed after 14 and 21 days, although the highest reduction occurred after 14 days under photoperiod incubation (84-98%). No clear light enhancing effect on the antifungal and anti-mycotoxin capability of the ZnO-NPs was observed. Morphological alterations in mycelia and conidia were observed by SEM. Under the in situ assay, the effect of the ZnO-NPs (0, 0.4, 0.8, 2 g kg^-1) on growth rates and fumonisin B₁, B₂ and B₃ accumulation by two F. proliferatum strains was evaluated on irradiated maize grains adjusted to 0.995, 0.98 and 0.97 a_W in darkness at 25 °C during 21 days. Also, zinc acetate at 0.8 g kg^-1 was included to compare their antifungal effect against the same ZnO-NPs concentration. Growth rates decreased significantly as ZnO-NPs concentrations increased. Higher than 60% of growth reduction was observed for both F. proliferatum strains. Zinc acetate significantly reduced growth, although it was less efficient that the same ZnO-NPs concentration. ZnO-NPs reduced total fumonisins accumulation by 71-99% at 0.8-2 g kg^-1 ZnO-NPs and 0.98-0.995 a_W. Moreover, 0.4 g kg^-1 ZnO-NPs also produced significant reduction of the 3 fumonisins. This study showed the application of ZnO-NPs in maize grains could be a low cost and environmental impact strategy to control phytopathogen and toxigenic fungi such as F. proliferatum and to reduce fumonisins accumulation, both during crop development at preharvest stage and during maize storage.

CuZn and ZnO Nanoflowers as Nano-Fungicides against Botrytis cinerea and Sclerotinia sclerotiorum: Phytoprotection, Translocation, and Impact after Foliar Application

Inorganic nanoparticles (INPs) have dynamically emerged in plant protection. The uptake of INPs by plants mostly depends on the size, chemical composition, morphology, and the type of coating on their surface. Herein, hybrid ensembles of glycol-coated bimetallic CuZn and ZnO nanoparticles (NPs) have been solvothermally synthesized in the presence of DEG and PEG, physicochemically characterized, and tested as nano-fungicides. Particularly, nanoflowers (NFs) of CuZn@DEG and ZnO@PEG have been isolated with crystallite sizes 40 and 15 nm, respectively. Organic coating DEG and PEG (23% and 63%, respectively) was found to protect the NFs formation effectively. The CuZn@DEG and ZnO@PEG NFs revealed a growth inhibition of phytopathogenic fungi Botrytis cinerea and Sclerotinia sclerotiorum in a dose-dependent manner with CuZn@DEG NFs being more efficient against both fungi with EC50 values of 418 and 311 μg/mL respectively. Lettuce (Lactuca sativa) plants inoculated with S. sclerotiorum were treated with the NFs, and their antifungal effect was evaluated based on a disease index. Plants sprayed with ZnO@PEG NFs showed a relatively higher net photosynthetic (4.70 μmol CO2 m-2s-1) and quantum yield rate (0.72) than with CuZn@DEG NFs (3.00 μmol CO2 m-2s-1 and 0.68). Furthermore, the penetration of Alizarin Red S-labeled NFs in plants was investigated. The translocation from leaves to roots through the stem was evident, while ZnO@PEG NFs were mainly trapped on the leaves. In all cases, no phytotoxicity was observed in the lettuce plants after treatment with the NFs.

The Effect of Monochromatic LED Light Wavelengths and Photoperiods on Botrytis cinerea

Botrytis cinerea is a ubiquitous necrotrophic pathogen causing grey mould in economically important crops. Light effect in horticulture is undeniable and fungi also react to light. Selected specific light-emitting diodes (LEDs) and photoperiods can be used for fungal pathogen inhibition. This study aimed to evaluate how LED light wavelengths and photoperiods affect the growth parameters of B. cinerea. The morphological (mycelium appearance, sclerotia distribution) and phenotypic (conidia presence and size, mycelium growth rate, recovery) characteristics of the fungal pathogen B. cinerea were evaluated under royal blue 455 nm, blue 470 nm, cyan 505 nm, yellow 590 nm, and red 627 nm LED lights at various photoperiods (4, 8, 12, 16, 20, 24 h). The results revealed that the light conditions and photoperiods influenced the B. cinerea morphological and phenotypic characteristics. Overall, the highest B. cinerea inhibition was under yellow (590 nm) LED light at 4 and 8 h photoperiods. Conidia did not form under blue 455 nm at 8, 16, 20, and 24 h photoperiods. Therefore, it can be assumed that the phenotypic and morphological features of B. cinerea depend on the specific photoperiod and LED light wavelength. The results allowed an exploration of original research approaches, raised new scientific questions for further investigation, and suggested new green plant protection solutions.

Visible light-activated ZnO nanoparticles for microbial control of wheat crop

Every year 15-50% of cereals all around the world are lost due to fungal contamination and deterioration. In addition, 25% of crops, which are used for human and animal consumption, are contaminated with mycotoxins. It is obvious, that more effective and sustainable technologies for better microbial control of crops are required. For this purpose we evaluated antibacterial and antifungal activity of ZnO nanoparticles (NPs) (10^-3-5 × 10^-3M) activated with visible light (405 nm, 18-30 J/cm²). Obtained data indicated that this treatment can inactivate human pathogen E. coli B by 6 log CFU without any possibility to regrowth after treatment. Wheat pathogen Fusarium oxysporum was inactivated by 51.7%. Results indicated that reactive oxygen species took place in the mechanisms of inactivation. Moreover, visible light activated ZnO NPs reduced the population of mesophiles on the surface of grains by 2.5 log CFU/g, inoculated E. coli- by 2.0 log CFU/g and naturally distributed fungi-by 2.1 log CFU/g. This treatment had no impact on visual quality of grains, did not inhibit grain germination rate and slightly promoted grain seedling growth. Concluding, the use of visible light driven photocatalysis in ZnO nanoparticles has huge potential to control plant pathogens, reduce food-borne diseases and subsequently enhance the sustainability in agriculture, meeting the increasing demands of a growing world population.