Grass-Shaped Zinc Oxide Nanoparticles Synthesized by the Sol-Gel Process and Their Antagonistic Properties towards the Biotrophic Parasite, Meloidogyne incognita.

The presence of Meloidogyne spp., also known as root-knot nematodes, presents a significant danger to global agricultural progress. Since chemical nematicides have high levels of toxicity, it is imperative to develop environmentally friendly methods to manage root-knot nematodes. Nanotechnology is now the most progressive way to attract researchers due to its innovative quality in combating plant diseases. Our study focused on the sol-gel process to synthesize grass-shaped zinc oxide nanoparticles (G-ZnO NPs) and assess its nematicidal behavior against Meloidogyne incognita. Various concentrations (250, 500, 750, and 1000 ppm) of G-ZnO NPs were utilized to expose both the infectious stage (J2s) and egg masses of M. incognita. Laboratory results revealed that G-ZnO NPs showed toxicity to J2s with LC50 values of 1352.96, 969.64, and 621.53 ppm at 12, 24, and 36 hours, respectively, and the result was the inhibition of egg hatching in M. incognita. All three exposure periods were reported linked with the concentration strength of G-ZnO NPs. The pot experiment results exhibited that G-ZnO NPs significantly reduced the root-gall infection of chickpea plants under M. incognita attack. Compared with the untreated control, there was a significant improvement in plant growth attributes and physiological parameters as well, when distinct G-ZnO NP doses (250, 500, 750, and 1000 ppm) were applied. In the pot study, we noticed a reduction in the root-gall index with an increase in the concentration of G-ZnO NPs. The results confirmed that G-ZnO NPs have enormous potential in sustainable agriculture for controlling the root-knot nematode, M. incognita, in chickpea production.

Purpureocillium lilacinum for plant growth promotion and biocontrol against root-knot nematodes infecting eggplant.

Purpureocillium lilacinum is a biocontrol Ascomycota fungus against various plant pathogens. In the present study, the efficacy of P. lilacinum was evaluated against a root-knot nematode, Meloidogyne incognita that infects eggplants. We performed an in vitro experiment in which the direct effects of P. lilacinum on the second-stage juvenile survival and egg hatching of M. incognita were tested at different exposure times. The results showed that P. lilacinum significantly reduced the rates of egg hatching and juvenile survival in a dose-dependent manner. Microscopic observation demonstrated that P. lilacinum directly penetrated the eggs and contacted the juveniles, indicating how P. lilacinum parasitizes M. incognita. We also performed a pot assay in which soil-grown eggplants were treated with P. lilacinum followed by inoculation with M. incognita. The results indicated that P. lilacinum effectively reduced the nematode population and the number of galls in plant roots. Interestingly, application of P. lilacinum resulted in significant enhancements in plant growth and biomass, even under nematode infection, while it improved plant photosynthetic pigments, i.e., chlorophyll and carotenoids. Taken together, our study suggested that P. lilacinum can be used as a plant growth-promoting fungus and a biological nematicide for disease management of root-knot nematodes in eggplants.

Effect of Phyto-Assisted Synthesis of Magnesium Oxide Nanoparticles (MgO-NPs) on Bacteria and the Root-Knot Nematode.

The root-knot nematode was examined using magnesium oxide nanoparticles (MgO-NPs) made from strawberries. The biologically synthesized MgO-NPs were characterized by UV, SEM, FTIR, EDS, TEM, and dynamic light scattering (DLS). Nanoparticles (NPs) were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and shown to be spherical to hexagonal nanoparticles with an average size of 100 nm. MgO-NPs were tested on the root-knot nematode M. incognita (Meloidogynidae) and the plant pathogenic bacteria Ralstonia solanacearum. The synthesized MgO-NPs showed a significant inhibition of R. solanacearum and the root-knot nematode. MgO-NPs cause mortality and inhibit egg hatching of second-stage juveniles (J2) of M. incognita under the in vitro assay. This study aims to examine the biological activity of biogenic MgO-NPs. The findings marked that MgO-NPs may be utilized to manage R. solanacearum and M. incognita and develop effective nematicides. In addition, the antioxidant capacity of MgO-NPs was determined by using 2, 2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH).

Screening of biosynthesized zinc oxide nanoparticles for their effect on Daucus carota pathogen and molecular docking.

Herein, we investigate the phytogenic synthesis of zinc oxide nanoparticles (ZnO-NPs) by using aqueous extract of seed coat of almond as a novel resource which can acts as a stabilizing and reducing agents. Successful biosynthesis of ZnO-NPs was observed by Ultraviolet-visible spectroscopy (UV-vis) showing peak at ~272 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the circular shape with an average size of ~20 nm. Applications of ZnO-NPs were observed on carrot (Daucus carota) plant infected with pathogenic fungus Rhizoctonia solani. Spray with 50 ppm and 100 ppm ZnO-NPs caused significant increase in plant growth attributes and photosynthetic pigments of carrot plants. It has been reported that the synthesized ZnO-NPs demonstrated an inhibitory activity against plant pathogenic fungus R. solani and reduces disease in carrot plants. Scanning electron microscopy and confocal microscopy indicated adverse effect of ZnO-NPs on pathogens. Antifungal efficiency of ZnO-NPs was further explained with help of molecular docking analysis. Conformation with highest negative binding energy was used to predict binding site of receptor with NPs to know mechanistic approach. ZnO-NPs are likely to interact with the pathogens by mechanical enfolding which may be one of the major toxicity actions against R. solani by ZnO-NPs. RESEARCH HIGHLIGHTS: ZnO nanoparticles were synthesized using waste material from the coat of almond seeds. Images from SEM, TEM, and related techniques like EDS and SAED revealed the irregularity of the ZnO NPs as well as their atom composition. FTIR and XRD analyses confirmed the formation and the presence of crystalline ZnO NPs in nature. Biogenic ZnONPs were found to be effective against the plant pathogenic fungus R. solani. A spray of 50 ppm and 100 ppm ZnO-NPs significantly increased carrot plant growth characteristics and photosynthetic pigments.

Search for Effective Approaches to Fight Microorganisms Causing High Losses in Agriculture: Application of P. lilacinum Metabolites and Mycosynthesised Silver Nanoparticles.

The manuscript presents the first report to produce silver nanoparticles (AgNPs) using soil-inhabiting Purpureocillium lilacinum fungus cell filtrate as a promising fungicide and nematicide on two microorganisms causing high economic losses in agriculture. METHODS: A fungus biomass was used as a reducing and stabilising agent in the process of NPs synthesis and then characterisation done by SEM, TEM, UV-Vis. Finally, the antimicrobial activity of the synthesised AgNPs was determined. RESULTS: Synthesised AgNPs with a spherical and quasi-spherical shape with an average diameter of 50 nm were effective to inhibit A. flavus fungi and M. incognita root knot nematode, which are extremely pathogenic for plants. Application of the AgNPs led to 85% reduction of proliferation of A. flavus, to a 4-fold decrease of hatching of M. incognita plant-parasite juveniles from eggs, and to a 9-fold increase of M. incognita nematode mortality. CONCLUSIONS: Biosynthesised AgNPs can be used as an effective fungicide and nematicide for food safety and security and improvement of agricultural production, but further agricultural field trials are required to observe their effect on environment and other factors.

Effects of Silicon and Silicon-Based Nanoparticles on Rhizosphere Microbiome, Plant Stress and Growth.

Silicon (Si) is considered a non-essential element similar to cadmium, arsenic, lead, etc., for plants, yet Si is beneficial to plant growth, so it is also referred to as a quasi-essential element (similar to aluminum, cobalt, sodium and selenium). An element is considered quasi-essential if it is not required by plants but its absence results in significant negative consequences or anomalies in plant growth, reproduction and development. Si is reported to reduce the negative impacts of different stresses in plants. The significant accumulation of Si on the plant tissue surface is primarily responsible for these positive influences in plants, such as increasing antioxidant activity while reducing soil pollutant absorption. Because of these advantageous properties, the application of Si-based nanoparticles (Si-NPs) in agricultural and food production has received a great deal of interest. Furthermore, conventional Si fertilizers are reported to have low bioavailability; therefore, the development and implementation of nano-Si fertilizers with high bioavailability could be crucial for viable agricultural production. Thus, in this context, the objectives of this review are to summarize the effects of both Si and Si-NPs on soil microbes, soil properties, plant growth and various plant pathogens and diseases. Si-NPs and Si are reported to change the microbial colonies and biomass, could influence rhizospheric microbes and biomass content and are able to improve soil fertility.

Antibacterial and Antifungal Studies of Biosynthesized Silver Nanoparticles against Plant Parasitic Nematode Meloidogyne incognita, Plant Pathogens Ralstonia solanacearum and Fusarium oxysporum.

The possibility of using silver nanoparticles (AgNPs) to enhance the plants growth, crop production, and control of plant diseases is currently being researched. One of the most effective approaches for the production of AgNPs is green synthesis. Herein, we report a green and phytogenic synthesis of AgNPs by using aqueous extract of strawberry waste (solid waste after fruit juice extraction) as a novel bioresource, which is a non-hazardous and inexpensive that can act as a reducing, capping, and stabilizing agent. Successful biosynthesis of AgNPs was monitored by UV-visible spectroscopy showing a surface plasmon resonance (SPR) peak at ~415 nm. The X-ray diffraction studies confirm the face-centered cubic crystalline AgNPs. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the rectangular shape with an average size of ~55 nm. The antibacterial and antifungal efficacy and inhibitory impact of the biosynthesized AgNPs were tested against nematode, Meloidogyne incognita, plant pathogenic bacterium, Ralstonia solanacearum and fungus, Fusarium oxysporum. These results confirm that biosynthesized AgNPs can significantly control these plant pathogens.

Selected nanotechnologies and nanostructures for drug delivery, nanomedicine and cure.

The development of nanoparticle-based drugs has provided many opportunities to diagnose, treat and cure challenging diseases. Through the manipulation of size, morphology, surface modification, surface characteristics, and materials used, a variety of nanostructures can be developed into smart systems, encasing therapeutic and imaging agents with stealth properties. These nanostructures can deliver drugs to specific tissues or sites and provide controlled release therapy. This targeted and sustained drug delivery decreases the drug-related toxicity and increases the patient's compliance with less frequent dosing. Nanotechnology employing nanostructures as a tool has provided advances in the diagnostic testing of diseases and cure. This technology has proven beneficial in the treatment of cancer, AIDS, and many other diseases. This review article highlights the recent advances in nanostructures and nanotechnology for drug delivery, nanomedicine and cures.

Recent progress of algae and blue-green algae-assisted synthesis of gold nanoparticles for various applications.

The hazardous effects of current nanoparticle synthesis methods have steered researchers to focus on the development of newer environmentally friendly and green methods for synthesizing nanoparticles using nontoxic chemicals. The development of environmentally friendly methods of nanoparticle synthesis with different sizes and shapes is one of the pressing challenges for the current nanotechnology. Several novel green approaches for the synthesis of AuNPs have been explored using different natural sources, such as plants, algae, bacteria, and fungi. Among organisms, algae and blue-green algae are of particular interest for nanoparticle synthesis. Gold nanoparticles (AuNPs) have a range of applications in medicine, diagnostics, catalysis, and sensors because of their significant key roles in important fields. AuNPs have attracted a significant interest for use in a variety of applications. The widespread use of AuNPs can be accredited to a combination of optical, physical, and chemical properties as well as the miscellany of size, shape, and surface composition that has been adopted through green synthesis methods.

Fungi-assisted silver nanoparticle synthesis and their applications.

Nanotechnology is a rapidly developing field because of its wide range of applications in science, nanoscience and biotechnology. Nanobiotechnology deals with nanomaterials synthesised or modified using biotechnology. Fungi are used to synthesise metal nanoparticles and they have vast applications in wound healing, pathogen detection and control, food preservation, textiles, fabrics, etc. The present review describes the different types of fungi used for the biosyntheses of silver nanoparticles (AgNPs), along with their characterisation and possible biological applications. AgNPs synthesised by other physical and chemical methods are expensive and have toxic substances adsorbed onto them. Therefore, green, simple and effective approaches have been chosen for the biosynthesis of AgNPs, which are very important because of their lower toxicity and environmentally friendly behaviour. AgNPs synthesised using fungi have high monodispersity, specific composition and a narrow size range. In this regard, among the different biological methods used for metal nanoparticle synthesis, fungi are considered to be a superior biogenic method owing to their diversity and better size control. To further understand the biosynthesis of AgNPs using various fungi and evaluate their potential applications, this review discusses the antimicrobial, antibacterial, antifungal, antiviral, antidermatophytic, anti-inflammatory, antitumor, hepatoprotective, cytotoxic, hypotensive, and immunomodulatory activities of these AgNPs. The synthesis of AgNPs using fungi is a clean, green, inexpensive, eco-friendly, reliable, and safe method that can be used for a range of applications in real life for the benefit of human beings.