Antifungal mechanisms of silver nanoparticles on mycotoxin producing rice false smut fungus

A review on accessible techniques for the management of rice false smut: recent research and future outlook

MAIN CONCLUSION

Rice false smut is an emerging threat to rice cultivation. Raising awareness about disease management strategies among scientists and rice growers is crucial to mitigating its impact. Modern advancements, including omics-based approaches such as genome assisted breeding, genetic engineering, genome editing, and nanotechnology, play a crucial role in developing effective management strategies to combat false smut. The world's rice supply is at risk from the fungal disease Ustilaginoidea virens, which causes rice false smut (RFS), can lead to significant production losses and quality degradation. In the past few decades, numerous strategies have been developed to combat this pervasive sickness, ranging from advanced biotechnology interventions to traditional farming practices. The development of nanotechnology has opened up new avenues for combating RFS by offering innovative ways to increase the precision and effectiveness of disease control tactics. This paper provides a comprehensive review of the long term strategies for managing rice fake smut, focusing on using multi-omics approaches combined with nanotechnology. Over the years, various strategies, from advanced biotechnology to traditional farming, have been developed to combat this disease. Nanotechnology offers innovative and efficient solutions for RFS management. We examined the past background of RFS management while assessing the merits and drawbacks of traditional techniques. Then, we explored the most recent developments in nano-technological applications like nano-pesticides, nanosensors, and nanoformulations, diagnostics developments, genome editing, molecular breeding along with metabolic engineering emphasizing how they could transform RFS control in different rice-growing areas globally. The current review is scrutinizes the foremost obstacles and applying sophisticated techniques for the management of RFS. The goal of this review is to close the gap between conventional wisdom and contemporary advancements by providing a comprehensive analysis of the diverse strategies needed to lessen the negative effects of RFS on the world's food security.

Endophytic fungi-bioinspired nanoparticles potential to control infectious disease

The growing demand for nanomedicine and its potentially diverse biological function required the investigation of raw materials for fabricating the nanomaterial. Current developments have emphasized the implementation of green chemistry to develop metal-oxide and metal nanoparticles. Endophytic fungi have emerged as a potential reservoir of bioactive compounds exemplified by unique structures and influential antibacterial properties. Over the past decade, substantial progress has been achieved in uncovering and profiling these valuable antibacterial compounds. These endophytic fungi-derived bioactive chemicals have diverse applications in various biological properties. Nanoparticle synthesis from materials derived from endophytic fungi, be it whole extracts or pure components, owing to their accessibility, cost-effectiveness in fabrication, material-tissue compatibility, and modest cytotoxicity toward higher organism cells. Nanoparticles from endophytic fungi have been utilized to treat various diseases, including those caused by bacterial, viral, and fungal pathogens. The present review provides a comprehensive discussion of the mechanistic insight into the synthesis and application of endophytic fungi-bioinspired nanoparticles as potential therapeutic agents to control microbial infection. The underlying action mechanism involved in the antimicrobial action of the nanoparticles has also been discussed. The discussion highlights various attributes of nanoparticles that may significantly benefit future researchers as potential therapeutic agents to control microbial infection.

Phytofabricated silver nanoparticles unlock new potential in tomato plants by combating wilt infection and enhancing plant growth

The environment faces serious threats from climate change, food security challenges, and a growing population. The UN Global Goals emphasize the urgent need for sustainable agriculture to secure food production. We must adopt innovative solutions to bolster agroecological resilience and increase food output with minimal environmental impact. Here, we investigate the antimycotic properties of silver nanoparticles (PP-AgNPs) at various concentrations in controlling Fusarium wilt for tomato crop improvement under laboratory, greenhouse, and field conditions. Various instruments were utilized to characterize the green-synthesized PP-AgNPs. The results indicated a broad UV peak at 428 nm and a spherical morphology with sizes ranging from 1 to 3.5 nm, as confirmed by SEM and TEM. Analyses indicate that the antifungal potency of PP-AgNPs (150 µg/mL) against Fusarium oxysporum was found to be 80.9% (Colony diameter: DA) and 95.4% (Measured area -MA), respectively, in contrast to the control treatment. Notably, the concentration of PP-AgNPs at 100 µg/mL signified the best effect under greenhouse and field trials, reducing disease severity by 34.5% (greenhouse) and 21.8% (Field: average of both years). PP-AgNPs also render other benefits, including improved plant growth parameters, fruit weight, number, and bioactive compounds. After exposure to PP-AgNPs, there was a significant increase in the expression of pathogenicity-related (PR), and defense genes at the molecular level. The physiological and molecular data are in-line induced antioxidative and defense responses after treatment with PP-AgNPs. Furthermore, the Ag content in various parts of tomato plants reveals no adverse effect on plant yield. Current research indicates that PP-AgNPs may be an effective and sustainable product for managing diseases and increasing crop yields in agriculture.

Molecular characterization of a novel narnavirus from the plant-pathogenic fungus Ustilaginoidea virens

Mycoviruses are viruses that infect fungi, yeasts, and oomycetes and can replicate and multiply within them. They are widely distributed in plant- and animal-pathogenic fungi. In this study, we identified a novel positive-sense single-stranded RNA (+ ssRNA) mycovirus from Ustilaginoidea virens strain Uv339, the causal agent of rice false smut (RSF), and this virus was named "Ustilaginoidea virens narnavirus 5" (UvNV5). Sequence analysis revealed that UvNV5 has a complete genome length of 2091 nt and contains a single open reading frame (ORF) (nt 131-2038) encoding a 635-amino-acid (aa) RNA-dependent RNA polymerase (RdRp) with a molecular mass of 71.8 kDa. BLASTp analysis revealed that the RdRp of UvNV5 shares only 38.22% amino acid sequence identity with that of Ustilaginoidea virens narnavirus virus 13, its closest relative. Phylogenetic analysis indicated that UvNV5 clustered within a branch alongside members of the class Amabiliviricetes. In summary, UvNV5 is a novel mycovirus of the class Amabiliviricetes that infects U. virens.

Multifaceted impacts of nanoparticles on plant nutrient absorption and soil microbial communities

With the growth of the global population and the increasing scarcity of resources, the sustainability and efficiency improvement of agricultural production have become urgent needs. The rapid development of nanotechnology provides new solutions to this challenge, especially the application of nanoparticles in agriculture, which is gradually demonstrating its unique advantages and broad prospects. Nonetheless, various nanoparticles can influence plant growth in diverse manners, often through distinct mechanisms of action. Beyond their direct effects on the plant itself, they frequently alter the physicochemical properties of the soil and modulate the structure of microbial communities in the rhizosphere. This review focuses intently on the diverse methods through which nanoparticles can modulate plant growth, delving deeply into the interactions between nanoparticles and plants, as well as nanoparticles with soil and microbial communities. The aim is to offer a comprehensive reference for the utilization of functionalized nanoparticles in the agricultural sector.

Selective biotic stressors' action on seed germination: A review

In the realm of plant biology and agriculture, seed germination serves as a fundamental process with far-reaching implications for crop production and environmental health. This comprehensive review seeks to unravel the intricate web of interactions between some biotic stressors and seed germination, addressing the pertinent issue of how these stressors influence seed germination. Different chemicals produced by interacting plants (different parts), fungi, bacteria, or insects can either promote or inhibit seed germination. Releasing chemicals that modulate signaling pathways and cellular processes significantly disrupt essential cellular functions. This disruption leads to diverse germination outcomes, introducing additional layers of complexity to this regulatory landscape. The chemicals perturb enzyme activity and membrane integrity, imposing unique challenges on the germination process. Understanding the mechanisms- how allelochemicals, mycotoxins, or bacterial toxins affect seed germination or the modes of action holds promise for more sustainable agricultural practices, enhanced pest control, and improved environmental outcomes. In sum, this review contributes to a fundamental exposition of the pivotal role of biotic stressors in shaping the germination of seeds.

Antifungal mechanism of nanosilver biosynthesized with Trichoderma longibrachiatum and its potential to control muskmelon Fusarium wilt

Fusarium oxysporum (Schl.) f.sp. melonis, which causes muskmelon wilt disease, is a destructive filamentous fungal pathogen, attracting more attention to the search for effective fungicides against this pathogen. In particular, Silver nanoparticles (AgNPs) have strong antimicrobial properties and they are not easy to develop drug resistance, which provides new ideas for the prevention and control of muskmelon Fusarium wilt (MFW). This paper studied the effects of AgNPs on the growth and development of muskmelon, the control efficacy on Fusarium wilt of muskmelon and the antifungal mechanism of AgNPs to F. oxysporum. The results showed that AgNPs could inhibit the growth of F. oxysporum on the PDA and in the PDB medium at 100-200 mg/L and the low concentration of 25 mg/L AgNPs could promote the seed germination and growth of muskmelon seedlings and reduce the incidence of muskmelon Fusarium wilt. Further studies on the antifungal mechanism showed that AgNPs could impair the development, damage cell structure, and interrupt cellular metabolism pathways of this fungus. TEM observation revealed that AgNPs treatment led to damage to the cell wall and membrane and accumulation of vacuoles and vessels, causing the leakage of intracellular contents. AgNPs treatment significantly hampered the growth of mycelia in the PDB medium, even causing a decrease in biomass. Biochemical properties showed that AgNPs treatment stimulated the generation of reactive oxygen species (ROS) in 6 h, subsequently producing malondialdehyde (MDA) and increasing protective enzyme activity. After 6 h, the protective enzyme activity decreased. These results indicated that AgNPs destroy the cell structure and affect the metabolisms, eventually leading to the death of fungus.

Co-infection of Four Novel Mycoviruses from Three Lineages Confers Hypovirulence on Phytopathogenic Fungus Ustilaginoidea virens

Rice false smut caused by Ustilaginoidea virens has become one of the most important diseases of rice. Mycoviruses are viruses that can infect fungi with the potential to control fungal diseases. However, little is known about the biocontrol role of hypoviruses in U. virens. In this study, we revealed that the hypovirulence-associated U. virens strain Uv325 was co-infected by four novel mycoviruses from three lineages, designated Ustilaginoidea virens RNA virus 16 (UvRV16), Ustilaginoidea virens botourmiavirus virus 8 (UvBV8), Ustilaginoidea virens botourmiavirus virus 9 (UvBV9), and Ustilaginoidea virens narnavirus virus 13 (UvNV13), respectively. The U. virens strain co-infected by four mycoviruses showed slower growth rates, reduced conidial yield, and attenuated pigmentation. We demonstrated that UvRV16 was not only the major factor responsible for the hypovirulent phenotype in U. vriens, but also able to prevent U. virens to accumulate more mycotoxin, thereby weakening the inhibitory effects on rice seed germination and seedling growth. Additionally, we indicated that UvRV16 can disrupt the antiviral response of U. virens by suppressing the transcriptional expression of multiple genes involved in autophagy and RNA silencing. In conclusion, our study provided new insights into the biological control of rice false smut.

"Therapeutic advancements in nanomedicine: The multifaceted roles of silver nanoparticles"

Nanotechnology has the advantages of enhanced bioactivity, reduced toxicity, target specificity, and sustained release and NPs can penetrate cell membranes. The small size of silver nanoparticles, AgNPs, large surface area, and unique physicochemical properties contribute to cell lysis and increased permeability of cell membranes used in the field of biomedicine. Functional precursors integrate with phytochemicals to create distinctive therapeutic properties and the stability of the nanoparticles can be enhanced by Surface coatings and encapsulation methods, The current study explores the various synthesis methods and characterization techniques of silver nanoparticles (AgNPs) and highlights their intrinsic activity in therapeutic applications, Anti-cancer activity noted at a concentration range of 5-50 μg/ml and angiogenesis is mitigated at a dosage range of 10-50 μg/ml, Diabetes is controlled within the same concentration. Wound healing is improved at concentrations of 10-50 μg/ml and with a typical range of 10-08 μg/ml for bacteria with antimicrobial capabilities. Advancement of silver nanoparticles with a focus on the future use of AgNPs-coated wound dressings and medical devices to decrease the risk of infection. Chemotherapeutic drugs can be administered by AgNPs, which reduces adverse effects and an improvement in treatment outcomes. AgNPs have been found to improve cell proliferation and differentiation, making them beneficial for tissue engineering and regenerative medicine. Our study highlights emerging patterns and developments in the field of medicine, inferring potential future paths.

Integrative transcriptomic and metabolomic analyses reveals the toxicity and mechanistic insights of bioformulated chitosan nanoparticles against Magnaporthe oryzae

Rice blast, an extremely destructive disease caused by the filamentous fungal pathogen Magnaporthe oryzae, poses a global threat to the production of rice (Oryza sativa L.). The emerging trend of reducing dependence on chemical fungicides for crop protection has increased interest in exploring bioformulated nanomaterials as a sustainable alternative antimicrobial strategy for effectively managing plant diseases. Herein, we used physiomorphological, transcriptomic, and metabolomic methods to investigate the toxicity and molecular action mechanisms of moringa-chitosan nanoparticles (M-CNPs) against M. oryzae. Our results demonstrate that M-CNPs exhibit direct antifungal properties by impeding the growth and conidia formation of M. oryzae in a concentration-dependent manner. Propidium iodide staining indicated concentration-dependent significant apoptosis (91.33%) in the fungus. Ultrastructural observations revealed complete structural damage in fungal cells treated with 200 mg/L M-CNPs, including disruption of the cell wall and destruction of internal organelles. Transcriptomic and metabolomic analyses revealed the intricate mechanism underlying the toxicity of M-CNPs against M. oryzae. The transcriptomics data indicated that exposure to M-CNPs disrupted various processes integral to cell membrane biosynthesis, aflatoxin biosynthesis, transcriptional regulation, and nuclear integrity in M. oryzae., emphasizing the interaction between M-CNPs and fungal cells. Similarly, metabolomic profiling demonstrated that exposure to M-CNPs significantly altered the levels of several key metabolites involved in the integral components of metabolic pathways, microbial metabolism, histidine metabolism, citrate cycle, and lipid and protein metabolism in M. oryzae. Overall, these findings demonstrated the potent antifungal action of M-CNPs, with a remarkable impact at the physiological and molecular level, culminating in substantial apoptotic-like fungal cell death. This research provides a novel perspective on investigating bioformulated nanomaterials as antifungal agents for plant disease control.

Ashikuzzaman, Md. Shamim Reja, Rahman MM, Khaton A, Tang MAK, Rahman MS, Hossain Md. Faruquee, Lee SJ, Rahman AM. Optimization of green silver nanoparticles as nanofungicides for management of rice bakanae disease

Rice bakanae, a devastating seed-borne disease caused by Fusarium species requires a more attractive and eco-friendly management strategy. The optimization of plant-mediated silver nanoparticles (AgNPs) as nanofungicides by targeting Fusarium species may be a rational approach. In this study, Azadirachta indica leaf aqueous extract-based AgNPs (AiLAE-AgNPs) were synthesized through the optimization of three reaction parameters: A. indica leaf amount, plant extract-to-AgNO3 ratio (reactant ratio), and incubation time. The optimized green AgNPs were characterized using ultraviolet-visible light (UV-Vis) spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and powder X-ray diffraction (XRD) techniques. The optimal conditions for producing spherical, unique, and diminutive-sized AgNPs ranging from 4 to 27 nm, with an average size of 15 nm, were 2 g AiLAE at a 1:19 ratio (extract-to-AgNO3) and incubated for 4 h. Fusarium isolates collected from infected soils and identified as F. fujikuroi (40) and F. proliferatum (58 and 65) by PCR were used for seed infestation. The AgNPs exhibited concentration-dependent mycelial growth inhibition with EC50 values ranging from 2.95 to 5.50 μg/mL. The AgNPs displayed exposure time-dependent seed disinfectant potential (complete CFU reduction in F. fujikuroi (40) and F. proliferatum (58) was observed at a concentration of 17.24 μg/mL). The optimized green AgNPs were non-toxic to germinating seeds, and completely cured bakanae under net-house conditions, suggesting their great nano-fungicidal potency for food security and sustainable agriculture.

Genome characterization of a novel narnavirus infecting the plant-pathogenic fungus Ustilaginoidea virens

Mycoviruses are viruses that infect fungi and oomycetes. They are widespread in all major groups of plant-pathogenic fungi and oomycetes. To date, only the full genome of dsRNA mycoviruses and the contigs of positive-sense single-stranded RNA (+ssRNA) mycoviruses have been reported in Ustilaginoidea virens, which is the notorious causal agent of rice false smut (RFS). Here, we report the molecular characterization of a novel +ssRNA mycovirus, Ustilaginoidea virens narnavirus 4 (UvNV4), isolated from U. virens strain Uv418. UvNV4 has a genome of 3,131 nucleotides (nt) and possesses an open reading frame (ORF) predicted to encode an RNA-dependent RNA polymerase (RdRp) of 1,017 amino acids (aa) sequence with a molecular mass of 116.6 kDa. BLASTp analysis revealed that the RdRp showed 50.34% aa sequence identity to that of the previously described Zhangzhou Narna tick virus 1. Phylogenetic analysis indicated that UvNV4 is closely related to members of the family Narnaviridae. Taken together, these results clearly demonstrate that UvNV4 is a novel +ssRNA virus infecting U. virens.

Nano-enabled seed treatment: A new and sustainable approach to engineering climate-resilient crops

Under a changing climate, keeping the food supply steady for an ever-increasing population will require crop plants adapted to environmental fluctuations. Genetic engineering and genome-editing approaches have been used for developing climate-resilient crops. However, genetically modified crops have yet to be widely accepted, especially for small-scale farmers in low-income countries and some societies. Nano-priming (seed exposure to nanoparticles, NPs) has appeared as an alternative to the abovementioned techniques. This technique improves seed germination speed, promotes seedlings' vigor, and enhances plant tolerance to adverse conditions such as drought, salinity, temperature, and flooding, which may occur under extreme weather conditions. Moreover, nano-enabled seed treatment can increase the disease resistance of crops by boosting immunity, which will reduce the use of pesticides. This unsophisticated, farmer-available, cost-effective, and environment-friendly seed treatment approach may help crop plants fight climate change challenges. This review discusses the previous information about nano-enabled seed treatment for enhancing plant tolerance to abiotic stresses and increasing disease resistance. Current knowledge about the mechanisms underlying nanomaterial-seed interactions is discussed. To conclude, the review includes research questions to address before this technique reaches its full potential.

Bioinspired silver nanoparticle-based nanocomposites for effective control of plant pathogens: A review

Plant pathogens, including bacteria, fungi, and viruses, pose significant challenges to the farming community due to their extensive diversity, the rapidly evolving phenomenon of multi-drug resistance (MDR), and the limited availability of effective control measures. Amid mounting global pressure, particularly from the World Health Organization, to limit the use of antibiotics in agriculture and livestock management, there is increasing consideration of engineered nanomaterials (ENMs) as promising alternatives for antimicrobial applications. Studies focusing on the application of ENMs in the fight against MDR pathogens are receiving increasing attention, driven by significant losses in agriculture and critical knowledge gaps in this crucial field. In this review, we explore the potential contributions of silver nanoparticles (AgNPs) and their nanocomposites in combating plant diseases, within the emerging interdisciplinary arena of nano-phytopathology. AgNPs and their nanocomposites are increasingly acknowledged as promising countermeasures against plant pathogens, owing to their unique physicochemical characteristics and inherent antimicrobial properties. This review explores recent advancements in engineered nanocomposites, highlights their diverse mechanisms for pathogen control, and draws attention to their potential in antibacterial, antifungal, and antiviral applications. In the discussion, we briefly address three crucial dimensions of combating plant pathogens: green synthesis approaches, toxicity-environmental concerns, and factors influencing antimicrobial efficacy. Finally, we outline recent advancements, existing challenges, and prospects in scholarly research to facilitate the integration of nanotechnology across interdisciplinary fields for more effective treatment and prevention of plant diseases.

Antifungal Activity and Action Mechanisms of 2,4-Di-tert-butylphenol against Ustilaginoidea virens

Ustilaginoidea virens is a destructive phytopathogenic fungus that causes false smut disease in rice. In this study, the natural product 2,4-di-tert-butylphenol (2,4-DTBP) was found to be an environmentally friendly and effective agent for the first time, which exhibited strong antifungal activity against U. virens, with an EC50 value of 0.087 mmol/L. The scanning electron microscopy, fluorescence staining, and biochemical assays indicated that 2,4-DTBP could destroy the cell wall, cell membrane, and cellular redox homeostasis of U. virens, ultimately resulting in fungal cell death. Through the transcriptomic analysis, a total of 353 genes were significantly upregulated and 367 genes were significantly downregulated, focusing on the spindle microtubule assembly, cell wall and membrane, redox homeostasis, mycotoxin biosynthesis, and intracellular metabolism. These results enhanced the understanding of the antifungal activity and action mechanisms of 2,4-DTBP against U. virens, supporting it to be a potential antifungal agent for the control of false smut disease.

Virulence traits and novel drug delivery strategies for mucormycosis post-COVID-19: a comprehensive review

The outbreak of a fatal black fungus infection after the resurgence of the cadaverous COVID-19 has exhorted scientists worldwide to develop a nutshell by repurposing or designing new formulations to address the crisis. Patients expressing COVID-19 are more susceptible to Mucormycosis (MCR) and thus fall easy prey to decease accounting for this global threat. Their mortality rates range around 32-70% depending on the organs affected and grow even higher despite the treatment. The many contemporary recommendations strongly advise using liposomal amphotericin B and surgery as first-line therapy whenever practicable. MCR is a dangerous infection that requires an antifungal drug administration on appropriate prescription, typically one of the following: Amphotericin B, Posaconazole, or Isavuconazole since the fungi that cause MCR are resistant to other medications like fluconazole, voriconazole, and echinocandins. Amphotericin B and Posaconazole are administered through veins (intravenously), and isavuconazole by mouth (orally). From last several years so many compounds are developed against invasive fungal disease but only few of them are able to induce effective treatment against the micorals. Adjuvant medicines, more particularly, are difficult to assess without prospective randomized controlled investigations, which are challenging to conduct given the lower incidence and higher mortality from Mucormycosis. The present analysis provides insight into pathogenesis, epidemiology, clinical manifestations, underlying fungal virulence, and growth mechanisms. In addition, current therapy for MCR in Post Covid-19 individuals includes conventional and novel nano-based advanced management systems for procuring against deadly fungal infection. The study urges involving nanomedicine to prevent fungal growth at the commencement of infection, delay the progression, and mitigate fatality risk.

Metal Nanomaterials and Hydrolytic Enzyme-Based Formulations for Improved Antifungal Activity

Active research of metal-containing compounds and enzymes as effective antifungal agents is currently being conducted due to the growing antifungal resistance problem. Metals are attracting special attention due to the wide variety of ligands that can be used for them, including chemically synthesized and naturally obtained variants as a result of the so-called "green synthesis". The main mechanism of the antifungal action of metals is the triggering of the generation and accumulation of reactive oxygen species (ROS). Further action of ROS on various biomolecules is nonspecific. Various hydrolytic enzymes (glucanases and proteases), in turn, exhibit antifungal properties by affecting the structural elements of fungal cells (cell walls, membranes), fungal quorum sensing molecules, fungal own protective agents (mycotoxins and antibiotics), and proteins responsible for the adhesion and formation of stable, highly concentrated populations in the form of biofilms. A wide substrate range of enzymes allows the use of various mechanisms of their antifungal actions. In this review, we discuss the prospects of combining two different types of antifungal agents (metals and enzymes) against mycelial fungi and yeast cells. Special attention is paid to the possible influence of metals on the activity of the enzymes and the possible effects of proteins on the antifungal activity of metal-containing compounds.

Silver nanoparticles green synthesized with leaf extract of disease-resistant amaranthus genotypes effectively suppress leaf blight (Rhizoctonia solani Kühn) disease in a susceptible red amaranthus cultivar

Silver nanoparticles (AgNPs) were green synthesized using leaf extract of the leaf blight disease (Rhizoctonia solani) susceptible red amaranthus (Amaranthus tricolor L.) and the disease-resistant green (A. dubius) and the wild amaranthus (A. viridis) genotypes, physically characterized, and assessed for their anti-fungal effects against R. solani. The green synthesized nanostructures showed an absorption maximum typical of silver nanoparticles in spectroscopy, and face-centered cubic structures in X-ray diffraction. Field Emission Scanning Electron Microscopic analysis and High-Resolution Transmission Electron Microscopy revealed the size range to be 35-45 nm for all the samples. In vitro mycelial growth inhibition of the pathogen occurred with 500 and 750 ppm concentrations of the nanoparticles in a poisoned-food assay. Further, detached leaves of red amaranthus variety were sprayed with the nanoparticles, and then challenged with the pathogen. There was significant difference in lesion development on leaves sprayed with Ad-AgNPs and Av-AgNPs compared to those treated with At-AgNPs. In the in vivo assay, challenging with the pathogen after spraying the foliage of the leaf blight susceptible red amaranthus variety with Ad-AgNPs at 750 ppm concentration recorded the lowest disease index (7.40) followed by that received Av-AgNPs spray at the same concentration (17.69), five days after inoculation. At-AgNPs treated plants had a disease index of 49.38. Our findings suggest that application of AgNPs green synthesized with leaf extract of disease-resistant genotypes of amaranthus effectively suppressed leaf blight disease incidence in a susceptible amaranthus genotype. To our knowledge, this is the first report on the improved plant pathogen-suppressive activity of any metal nanoparticle when biogenically synthesized using extracts from a disease-resistant plant genotype.