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.

In the present era, the global need for food is increasing rapidly; nanomaterials are a useful tool for improving crop production and yield. The application of nanomaterials can improve plant growth parameters. Biotic stress is induced by many microbes in crops and causes disease and high yield loss. Every year, approximately 20–40% of crop yield is lost due to plant diseases caused by various pests and pathogens. Current plant disease or biotic stress management mainly relies on toxic fungicides and pesticides that are potentially harmful to the environment. Nanotechnology emerged as an alternative for the sustainable and eco-friendly management of biotic stress induced by pests and pathogens on crops. In this review article, we assess the role and impact of different nanoparticles in plant disease management, and this review explores the direction in which nanoparticles can be utilized for improving plant growth and crop yield.

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.

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.

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.

Root-knot nematodes are a major global agricultural pest. They infiltrate plant roots, reducing the plants’ ability to absorb nutrients and water, which significantly affects agricultural productivity. Due to the restricted use of chemical nematicide, environmentally friendly alternatives have been explored. In this study, we developed a polymerase chain reaction (PCR) assay to detect Meloidogyne javanica, a root knot nematode specifically infectious to eggplant. Using this detection method, we assessed the nematicidal activity of the biocontrol agent Pochonia chlamydosporia against M. javanica infection. We also assessed the in vitro mortality of M. javanica J2 larvae and eggs hatching following treatment with P. chlamydosporia. Additionally, we performed assays for penetration, population, and reproduction in pots containing eggplants infected with M. javanica and treated or untreated with P. chlamydosporia. P. chlamydosporia at various doses significantly inhibited M. javanica egg hatching and second-stage juveniles. It effectively reduced the number of galls, egg masses, and the nematode population in the roots of pot-grown eggplants. Furthermore, P. chlamydosporia treatment improved the growth parameters and photosynthetic pigments of eggplants while decreasing infection. Thisstudy highlights the potential of P. Chlamydosporia in managing root knot disease in eggplant.