Aranzazu Gomez-Garay

Seed germination is a critical developmental transition regulated by coordinated physiological and biochemical processes during the triphasic imbibition process. Water uptake is followed by membrane repair, restoration of mitochondrial respiration, ATP production and activation of hydrolytic enzymes involved in reserve mobilization. In this context, silver nanoparticle (AgNP) seed priming has emerged as a promising strategy to enhance germination by modulating early biochemical events through controlled redox signalling, although its effects vary among species and experimental conditions. This review integrates physiological, biochemical and molecular evidence to propose a seed-centred mechanistic framework explaining how AgNPs regulate germination through redox-dependent signalling networks. During imbibition, low AgNP concentrations can induce transient reactive oxygen species production through the combined effects of nanoparticles and released Ag⁺ ions, together with moderate thiol-based redox shifts acting as developmental signals. These signals activate antioxidant systems, mitogen-activated protein kinase cascades and hormone-dependent pathways coordinating metabolic activation and membrane repair. Controlled redox modulation may also establish a primed physiological state that improves tolerance to abiotic stress during early seedling establishment. In contrast, excessive AgNP or Ag⁺ exposure disrupts glutathione-based redox buffering, causing oxidative damage, mitochondrial dysfunction and inhibition of germination. The magnitude and direction of these responses depend on intrinsic seed traits, including seed coat permeability, imbibition kinetics and antioxidant capacity, as well as nanoparticle properties such as size, surface chemistry and ion release dynamics. Distinguishing nanoparticle-specific effects from Ag⁺-mediated toxicity is therefore essential for interpreting nanopriming outcomes and developing safe, species-specific crop applications.

Agriculture faces escalating challenges from pests, diseases, and climatic stresses that threaten global food security. Green nanotechnology offers a sustainable approach to enhance crop protection and productivity by using plant-based methods to synthesize metallic nanoparticles (NPs), reducing chemical inputs and environmental impacts. This review presents the framework of green nanotechnology in agriculture, focusing on biogenic sources of nanoparticle synthesis (especially plant extracts), mechanisms of nanoparticle formation and stabilization by phytochemicals, and characterization techniques for green-synthesized NPs. We examine the application of plant-derived metallic nanoparticles as nanofertilizers to improve nutrient use efficiency and crop yields, as nanopesticides to manage plant pathogens and pests, and as nano-enabled agents to enhance tolerance to abiotic stresses such as salinity and drought. Recent studies demonstrate that green-synthesized NPs can increase wheat and rice yields by 13–55%, improve nutrient-use efficiency by up to 80–90% compared to conventional fertilizers, and provide effective pathogen control at reduced active ingredient doses, while reducing dependence on conventional agrochemicals. The review also discusses key challenges limiting large-scale adoption, including production scalability, biological variability in synthesis, potential phytotoxicity at high concentrations, regulatory uncertainties, and gaps in knowledge regarding nanoparticle fate and safety. Overall, green-synthesized metallic nanoparticles emerge as promising tools for improving crop productivity and protection in an eco-friendly manner, supporting the transition toward more sustainable agricultural systems.

Grapevine trunk diseases, particularly those caused by Neofusicoccum parvum, represent a major threat to vineyard productivity and are increasingly difficult to control with conventional fungicides. Green synthesis of silver nanoparticles (AgNPs) using biocontrol fungi offers a promising alternative, but the factors governing the efficiency and bioactivity of biogenic nanoparticles remain poorly understood. Here, three Trichoderma species (T. harzianum, T. asperellum and T. virens) were evaluated as biological nanofactories for AgNP production. Cell-free fungal filtrates were used to synthesize AgNPs, which were characterized by UV–visible spectrophotometry, Dynamic Light Scattering (DLS) and transmission electron microscopy, while fungal redox metabolism was assessed using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays and HPLC profiling of extracellular metabolites. AgNPs were tested against two isolates of N. parvum in vitro. The Trichoderma strains differed markedly in nanoparticle yield, size and antifungal activity, with T. harzianum T0 producing the highest amounts of small, well-dispersed AgNPs that exerted a strong fungistatic effect on N. parvum. Nanoparticle production correlated with antioxidant capacity and the abundance of redox-active metabolites. Integration of these parameters into a Fungal Nanofactory Efficiency Index (FNEI) revealed that nanoparticle bioactivity depends on both dose and biological origin. These results demonstrate that fungal metabolism is a key determinant of biogenic nanoparticle performance and identify Trichoderma as a platform for sustainable nanotechnology-based control of grapevine trunk pathogens.

Agriculture faces escalating challenges from pests, diseases, and climatic stresses that threaten global food security [1,2]. Green nanotechnology offers a sustainable approach to enhance crop protection and productivity by using plant-based methods to synthesize metallic nanoparticles (NPs), reducing chemical inputs and environmental impacts [3,4]. This review presents the framework of green nanotechnology in agriculture, focusing on biogenic sources of nanoparticle synthesis (especially plant extracts), mechanisms of nanoparticle formation and stabilization by phytochemicals, and characterization techniques for green-synthesized NPs. We examine the application of plant-derived metallic nanoparticles as nanofertilizers to improve nutrient use efficiency and crop yields, as nanopesticides to manage plant pathogens and pests, and as nano-enabled agents to enhance tolerance to abiotic stresses such as salinity and drought. Recent studies demonstrate that green-synthesized NPs can significantly increase crop growth and productivity while reducing dependence on conventional agrochemicals [5]. The review also discusses key challenges limiting large-scale adoption, including production scalability, biological variability in synthesis, potential phytotoxicity at high concentrations, regulatory uncertainties, and gaps in knowledge regarding nanoparticle fate and safety [6,7]. Overall, green-synthesized metallic nanoparticles emerge as promising tools for improving crop productivity and protection in an eco-friendly manner, supporting the transition toward more sustainable agricultural systems.

Vitis vinifera is highly susceptible to grapevine trunk diseases, with Neofusicoccum parvum recognized as a highly destructive pathogen. This study investigates the biocontrol potential of five Trichoderma species (T. harzianum, T. viride, T. asperellum, and T. virens) against N. parvum, evaluating multiple biocontrol mechanisms (mycoparasitism, competition for nutrients, production of volatile organic compounds (VOCs), and antibiosis) as well as their compatibility with the fungicides copper oxychloride and sulfur. Results demonstrated that (1) Trichoderma harzianum effectively suppressed N. parvum through VOC production, mycoparasitism, and nutrient competition, significantly reducing pathogen growth in planta while showing compatibility with both fungicides, highlighting its suitability for integrated disease management; (2) Trichoderma viride showed high inhibition of N. parvum in vitro, but its phytotoxicity in planta limits its field application. These findings support T. harzianum as a promising agent within integrated disease management strategies, offering a sustainable alternative to reduce chemical fungicide reliance in controlling grapevine trunk pathogens.

This study presents a novel green synthesis method for aluminum phosphate (AlPO₄) nanoplates using extracts from Quercus suber somatic embryos. Traditionally, metallic nanoparticles are synthesized using harmful chemical reagents and solvents, but our approach leverages bioactive compounds, such as phytic acid (IP6) from plant extracts, offering a more sustainable alternative. We observed a high phosphate content of 23.6 μMol PO₄³⁻/mg dry weight (DW) in the extracts, which is significantly higher than in other Quercus species. Characterization through UV–VIS spectroscopy and XRD confirmed the formation of complex crystal nanoplates, where anisotropic aluminum phosphate with a triclinic crystal structure coexists with monoclinic structures, both forms of aluminum phosphate tridymite. Electron microscopy (TEM and SEM) revealed the hierarchical organization of these nanoplates, distinguishing them from the more commonly observed spherical nanoparticles. Fourier-transform infrared (FTIR) spectroscopy further validated the incorporation of phytic acid into the nanoplate structure. This innovative method not only advances sustainable nanomaterial synthesis but also demonstrates the potential for unique optical and structural properties in aluminum phosphate nanoplates, paving the way for future applications in specialized fields.

This study investigates the enhanced production of key therapeutic metabolites (ellagic acid, serotonin, and chlorogenic acid) in response to abiotic stress in in vitro cultures of Quercus suber somatic embryos. Findings indicate significant increases in metabolite levels under various stress conditions, highlighting the potential for commercial-scale production of these compounds, known for their antioxidant, anticancer, and anti-COVID-19 properties. Under osmotic/saline stress, ellagic acid production significantly increased, representing an 80% increase compared to control conditions. In embryos exposed to different stressors, serotonin accumulation showed a six-fold increase under osmotic/saline stress. Although the elicitors used did not increase chlorogenic acid levels, exploring alternative stress types may enhance its production. This research paves the way for sustainable, large-scale production of health-beneficial metabolites, addressing global health challenges and promoting resource sustainability.

Nanopriming, a technique that involves treating seeds with nanoparticles, is gaining attention for enhancing seed germination and seedling growth. This study explored the effects of silver nanoparticles (AgNPs), synthesized using Ascorbic acid, Caffeic acid, and Gallic acid, on cucumber seedling development. The nanoparticles, characterized by spherical morphology and distinct optical properties, showed varying effects based on the type and concentration of the reducing agents used. AgNP treatments generally led to higher germination rates and improved shoot and root growth compared to controls. Biochemical analyses revealed that these treatments influenced plant physiology, affecting reactive oxygen species (ROS) production, oxidative stress markers, and the content of amino acids, phenolic compounds, flavonoids, and soluble sugars. Specifically, certain AgNP treatments reduced oxidative stress, while others increased oxidative damage. Additionally, variations in free amino acids and phenolic and flavonoid contents were noted, suggesting complex interactions between nanoparticles and plant biochemical pathways. These findings highlight the potential of nanopriming in agriculture and underscore the need for further research to optimize nanoparticle formulations for different plant species.

This study aims to evaluate the biocontrol potential of Meyerozyma guilliermondii (CECT13190), an endophytic yeast, and its role in mitigating the adverse effects of abiotic and biotic stress in cucumber plants. The relevance of this study lies in addressing the threat of Fusarium wilt, a major fungal disease that impacts cucumber crop productivity, as well as the exacerbation of food scarcity caused by climate change-induced abiotic stress factors such as high temperatures and drought. The study was conducted in a greenhouse environment where Cucumis sativus seedlings were exposed to biotic (F. oxysporum inoculation) and abiotic stress conditions (heat and water deficit). The impact of M. guilliermondii on treated plants’ physiology, growth, development, and flowering was assessed. The study confirmed the biocontrol activity of M. guilliermondii against F. oxysporum and highlighted its positive effects as a plant growth promoter. It enhanced overall plant health, activated natural defense mechanisms against F. oxysporum, and alleviated the detrimental impacts of abiotic stress. Notably, M. guilliermondii also induced early flowering in cucumber plants. This research underscores the potential of M. guilliermondii as a biocontrol agent for managing Fusarium wilt, enhancing stress tolerance, promoting early flowering, and offering promising prospects for sustainable crop production amidst fungal diseases and climate change-induced stressors. The findings emphasize the importance of utilizing M. guilliermondii to improve cucumber crop productivity and address food scarcity challenges.

This article emphasizes the crucial importance of yeast Meyerozyma guilliermondii (Patent CECT13190) as a biological control agent (BCA) in eliciting defensive responses in vine plants, and is supported by comprehensive physiological, proteomic, and transcriptomic analyses. The results demonstrate that the BCA M. guilliermondii can induce enhanced defensive responses, as reflected in the regulation of key proteins. Notably, the upregulated expression of calmodulin and pathogenesis-related protein 10 (PR-10) are indicative of a complex interplay between calcium signalling, salicylic acid accumulation, and the elicitation of plant defence responses against pathogens. Furthermore, changes in microtubule dynamics and proteins related to protein synthesis and folding are observed, confirming the elicitation of defence responses. The correspondence between proteomic and transcriptomic analyses for genes codifying pathogenesis-related proteins, such as Vcgns1, VviTL1, and Vcchit1b, reinforces the empirical robustness of our findings. Collectively, our research explores the modulation of plant defences by the BCA, opening promising avenues for innovative agricultural strategies that enhance crop resilience and productivity.