Silver Nanoparticles in Phytopathogen Management

Silver nanoparticles (AgNPs) have emerged as versatile agents in the control of plant diseases, combining potent antifungal and antibacterial properties with the potential for eco-friendly production. Their efficacy arises from nanoscale dimensions and high surface-to-volume ratios, which facilitate interactions with microbial cells, induce generation of reactive oxygen species, disrupt membrane integrity and impair vital enzymes. A range of synthesis approaches—chemical reduction, physical methods and, increasingly, green or biosynthetic routes using plant extracts, algae or microbial cultures—allow fine tuning of particle size, shape and surface chemistry. In both laboratory and field trials, AgNPs have been applied as seed treatments, foliar sprays and post-harvest coatings to suppress a spectrum of phytopathogens, including Fusarium, Alternaria and Penicillium species. Demonstrated benefits include delayed symptom onset, reduced spoilage, enhanced plant defence responses and improved crop quality. To realise widespread adoption, current research is addressing challenges in large-scale production, environmental fate, phytotoxicity thresholds and integration with existing plant-protection strategies. By offering a sustainable alternative to conventional fungicides, silver nanoparticle technology holds global significance for food security and the reduction of chemical residues in agroecosystems.

Research from Nature Portfolio

Recent studies have demonstrated that the surface chemistry of AgNPs critically influences antifungal performance. By comparing citrate-stabilised, negatively charged particles with cysteamine-capped, positively charged ones, researchers revealed that the latter exhibited enhanced silver ion release, stronger adhesion to Fusarium cell walls, membrane penetration and superior inhibition of both mycelial growth and spore viability. These findings underline the importance of surface charge engineering in designing nanofungicides with tunable activity.

Work on biosynthesis of AgNPs using a soil bacterium has shown that spherical nanoparticles of around 12 nm can be produced in a single step and deployed against soil-borne and foliar pathogens. In vitro assays confirmed complete inhibition of sclerotia germination in Sclerotium rolfsii, and greenhouse trials on chickpea demonstrated reduced collar rot severity. Mechanistic studies pointed to induction of lignification, elevated hydrogen peroxide production and modulation of phenolic acids as key plant defence-priming events.

Silver Nanoparticles in Phytopathogen Management publication trend

The graph below shows the total number of articles in silver nanoparticles in phytopathogen management across all publications each year (not limited to Nature Index journals).

Technical terms

Silver nanoparticle: A particle of metallic silver with dimensions typically below 100 nm, exhibiting unique surface-mediated antimicrobial properties.

Phytopathogen: A microorganism—most often a fungus, bacterium or virus—that causes disease in plants.

Biosynthesis (green synthesis): Production of nanoparticles using biological agents (e.g. plant extracts, algae or microbes) that act as reducing and stabilising agents.

Reactive oxygen species (ROS): Highly reactive molecules containing oxygen, such as superoxide or hydrogen peroxide, which can damage cellular components.

Mycelial growth: The expansion of fungal hyphae, often measured as the increase in colony diameter or biomass over time.

Surface plasmon resonance (SPR): The collective oscillation of conduction electrons on the surface of metal nanoparticles, observable as a distinct absorbance peak in UV–visible spectra.

References

1. Antifungal Activities of Biogenic Silver Nanoparticles Mediated by Marine Algae: In Vitro and In Vivo Insights of Coating Tomato Fruit to Protect against Penicillium italicum Blue Mold. Marine Drugs (2024).
2. Antifungal Properties of Bio-AgNPs against D. pinodes and F. avenaceum Infection of Pea (Pisum sativum L.) Seedlings. International Journal of Molecular Sciences (2024).
3. Potential of biosynthesized silver nanoparticles using Stenotrophomonas sp. BHU-S7 (MTCC 5978) for management of soil-borne and foliar phytopathogens. Scientific Reports (2017).
4. Surface properties-dependent antifungal activity of silver nanoparticles. Scientific Reports (2022).
5. The antifungal activity and mechanism of silver nanoparticles against four pathogens causing kiwifruit post-harvest rot. Frontiers in Microbiology (2022).