Search Results (1,872)

Green husks, which are the fleshy pericarp of Juglans regia L. fruit, are an abundant yet under-utilized source of bioactive compounds. They are useful for plant defense and have potential for valorization to multiple commercial products. This study characterized total phenolic content (TPC) and individual phenolics in green husks of four Hungarian-bred cultivars (Milotai 10, Milotai intenzív, Milotai kései, Esterhazy kései) and one U.S. cultivar (Chandler). Phenolic compounds were extracted with aqueous organic solvents, quantified by HPLC-DAD and qualitatively identified by HPLC-MS. Linear mixed-effects models were used to assess the effects of cultivar, year, sampling time, and cumulative growing degree days (GDDs) on TPC and compound profiles. Mean TPC ranged from 34.9 to 57.2 mg GAE g⁻¹ DW, with significantly higher values in the warmest year, 2024, and in cultivar Esterhazy kései compared with Chandler. Across cultivars and years, phenolic levels were generally elevated at early lignification (S1, BBCH 73–75) and at full maturity (S5–S6, BBCH 87–88), with depressed concentrations during mid-fruit development (S2–S4, BBCH 77–86). Several hydroxycinnamic acids, flavonoids, and naphthoquinones showed cultivar-specific and year-dependent patterns. Thermal conditions (cumulative GDDs) explained a substantial proportion of residual variation in TPC. These results highlight the combined roles of genotype, seasonal climate, and developmental stage dependencies in biosynthetic processes of phenolics in walnut green husks despite the diversity in factor effects. Full article

Salicylic acid (SA) is involved in plant defense responses to environmental stressors by modulating gene expression and specialized metabolites production, enhancing plant adaptive resilience through systemic signaling pathways. This study investigates the impact of exogenous application of SA on the metabolism of iridoids and phenolic compounds—characteristic specialized metabolites of the Nepeta species, associated with diverse biological activities. Nepetalactone (NL) is a characteristic monoterpene iridoid, while rosmarinic acid (RA) represents the most abundant phenolic compound within the genus. We explored the effects of varying SA concentrations (2 µM, 5 µM, 10 µM, and 20 µM) on iridoid and phenolic metabolism in in vitro-grown Nepeta nuda, following 7 days and 28 days of elicitation. A significant increase in trans,trans-NL content was observed after 7-day exposure to 2 µM SA, while prolonged exposure led to a decrease in its levels, particularly at higher SA concentrations. Gene expression analysis revealed that 7 days of exposure to lower concentrations of SA upregulated genes coding for NAD-dependent nepetalactol-related short-chain dehydrogenase/reductases (NEPSs), key regulatory enzymes catalyzing the final steps of NL biosynthesis. In contrast, prolonged exposure to 20 µM SA downregulated genes coding for geraniol 8-hydroxylase (NnG8H) and 8-hydroxygeraniol oxidoreductase (Nn8HGO), which resulted in reduced iridoid content. Conversely, SA treatment notably increased RA content after prolonged exposure to 20 µM SA, which is a result of the enhanced expression of all analyzed RA biosynthesis-related genes. These findings demonstrate that both concentration and duration of SA treatment are critical determinants of elicitation outcomes in N. nuda. Strategic manipulation of these parameters can redirect metabolic flux toward either iridoid or phenolic compounds production, and enhance biotechnological production of specialized metabolites in N. nuda. Full article

To explore the seasonal variation patterns of the skin microecology of Altay sheep under transhumant grazing conditions, skin swabs were collected from 60 free-grazing Altay sheep at seasonal transition nodes in the Altay region. Metagenomic sequencing combined with untargeted metabolomics was used to characterize their bacterial community structure, functional pathways, and metabolite profiles. The results showed that the skin microecology of Altay sheep presented obvious seasonal variation patterns. In spring, 35 of the 39 highly abundant bacteria were environmentally derived, five proliferation-related pathways were significantly enriched, and the levels of five metabolites associated with microbial community regulation and skin barrier defense were elevated. In summer, the abundance of three skin symbiotic bacteria increased, the activities of eight pathways mainly related to biofilm formation were significantly enhanced, and the contents of five metabolites primarily associated with membrane lipid homeostasis and selective bacteriostasis increased. In autumn, the abundances of nine radiation-resistant and cold-tolerant strains increased, together with the elevated abundance of two opportunistic pathogens; five repair-related pathways were active, and the levels of four anti-inflammatory and repair-associated metabolites were synchronously increased. In winter, the abundance of two cold-tolerant strains increased, the activities of pathways related to nitrogen metabolism and energy synthesis were enhanced, and one lignan compound was identified as the key metabolite. These findings elucidate the seasonal dynamic patterns of the skin microecology of Altay sheep and provide a theoretical basis for research on the adaptive mechanisms and seasonal health management of Altay sheep and other sheep in alpine regions. Full article

Cadmium (Cd) accumulation in plant tissues causes several damages, including disturbances in anatomical structures, negative impacts on photochemical reactions, and reducing the efficiency of the photosynthetic apparatus. 24-Epibrassinolide (EBR) is a plant steroid that regulates multiple physiological and biochemical processes to counteract the harmful effects of metal stress. The aim of this research was to investigate whether exogenous EBR application affects leaf and root anatomical structures, including stomatal responses, redox-metabolism-related biochemical responses intrinsically related to photosynthetic apparatus, and nutritional status in soybean plants under Cd excess. The experiment was randomized with four treatments: two cadmium concentrations (0 and 500 µM Cd, described as −Cd and +Cd, respectively) and two EBR levels (0 and 100 nM EBR, described as −EBR and +EBR, respectively). Results demonstrated that EBR positively regulated root and leaf structures and stomatal performance, with significant increases in epidermis and cortex (root) and benefits for spongy parenchyma and stomatal density (leaf), clearly protecting the photosynthetic apparatus against Cd excess. Simultaneously, this steroid mitigated Cd-induced oxidative stress by stimulating the activities of superoxide dismutase (25%), catalase (28%), ascorbate peroxidase (30%) and peroxidase (48%), while simultaneously reducing the content of oxidative compounds, including superoxide (16%), hydrogen peroxide (8%), malondialdehyde (12%) and electrolyte leakage (14%). The dual mechanism modulated by EBR protected anatomical structures and stimulated antioxidant defense. Therefore, the results prove that exogenous EBR application effectively attenuates the adverse effects of Cd excess in soybean plants. Full article

Traditional disease management, which is based on the application of synthetic chemical products, has negatively affected human health and the environment. A sustainable approach based on the application of natural compounds and microorganisms is potentially better for consumer health. Thus, the aim of this study was to evaluate the efficacy of plant-based and/or organic products against soilborne fungal pathogens of tomato. A preliminary in vitro experiment was performed to select potential putative inhibitory products (PIPs) and fungal pathogens that were then used in an in vivo experiment conducted inside a greenhouse that mimics real-world field conditions. For the greenhouse experiment, bergamot and pomegranate wastes and the commercial product EP5 were selected as the PIPs to control Agroathelia rolfsii, Fusarium oxysporum and Sclerotinia sclerotiorum growth. Each pot was artificially inoculated three days before the low-dose treatment, and one tomato seedling was transplanted into each pot four days after the treatment. Data regarding the phytosanitary status of the plants and roots, as well as their length and weight, were collected after 45 days, and the results obtained demonstrate that plant-derived products were able to mitigate fungal diseases, with pomegranate waste being the most effective. Also, the EP5 product, as a resistant inducer, was able to significantly improve the natural defense of tomato plants, resulting in it being the best PIP used. Mycological analyses were performed on the roots to assess the presence of inoculated fungal pathogens after natural product treatment. Overall, the results confirm that the PIPs are suitable for crop management, but the outcomes are variable. In general, pomegranate waste and EP5 significantly protected the roots against fungal attacks, while bergamot waste showed lower efficacy. This trend was not observed for plant length and weight, as the treated plants showed results similar to those of the untreated controls. In conclusion, natural products are a valid alternative to chemicals, as they demonstrate both efficacy and safety, but their potential should be further investigated in field trials. Full article

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide, with oxidative stress playing a major role in disease pathogenesis by promoting endothelial dysfunction, vascular inflammation, and tissue damage. Oxidative stress results from an imbalance between antioxidant defenses and reactive oxygen species (ROS) in favor of ROS. Excessive ROS damage macromolecules and may trigger a chain reaction of lipid peroxidation, protein modification, and DNA damage. Phytochemicals are naturally occurring compounds in fruits and vegetables that may modulate redox homeostasis and positively impact cardiovascular health. The flavonoid Quercetin, Resveratrol, Curcuminoids, Coenzyme Q10, Hydroxysafflor yellow A, and Vitamins C and E have shown promise in human studies for improving endothelial function, lipid profile and markers of oxidative stress and inflammation. Among the key mechanisms of protection are their antioxidant role, anti-inflammatory role or modulation of nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, all of which contribute to cardiovascular protection. However, there are challenges associated with their use for health, such as the complexity of their quality and quantity, which require standardization, as well as their mechanisms of effects. Moreover, their systemic availability and bioactivity largely depend on metabolic transformation by the host gut microbiota. This review analyzed relevant publications in PubMed, Scopus, and Web of Science, up to February 2026, and summarizes current knowledge on phyto–chemical-mediated modulation of oxidative stress and its implications for cardiovascular protection in humans. The evidence suggests that phytochemicals hold promise for CVD prevention and treatment, but more work is needed to achieve standardization in quality and quantity. Full article

Actinidia arguta is a valuable plant resource known for its diverse bioactive constituents. However, organ-dependent metabolic variation remains insufficiently explored. In this study, an integrated approach combining LC–QTOF–MS-based metabolomic profiling, multivariate analysis, and phytochemical isolation was employed to investigate metabolic differences among fruits, leaves, and roots of A. arguta. Comparative LC–QTOF–MS profiling and principal component analysis (PCA) revealed clear organ-specific metabolic differentiation. The root extract formed a distinct cluster, primarily characterized by flavan-3-ol oligomers, including procyanidin dimers and a trimer. Targeted isolation and spectroscopic analysis identified these compounds as major constituents of the root. Quantitative analysis showed that the root exhibited the highest antioxidant activity (60.8 ± 6.2%) and total phenolic content (10.8 ± 0.7 mg GAE/g dried weight), followed by leaves and fruits, indicating significant organ-dependent variation. The enhanced antioxidant activity observed in the root extract was consistent with the enrichment of oligomeric procyanidins, which are known for their strong radical-scavenging capacity. These findings demonstrate pronounced organ-specific metabolic specialization in A. arguta, with the root characterized by a condensed tannin–dominant chemical profile. This study highlights the potential of root-derived procyanidins as bioactive natural products and provides a basis for their utilization in functional and phytochemical applications, as well as insights into plant defense-related metabolism. Full article

Eucalyptus spp. are the most important timber and pulpwood species in southern China. This tree species is frequently and severely damaged by the leaf-eating pest Buzura suppressaria, which significantly impairs photosynthesis and hinders the healthy and sustainable development of the Eucalyptus industry. To investigate the defensive responses of Eucalyptus urophylla × Eucalyptus grandis to pest (B. suppressaria)-feeding and leaf-clipping stress, this study measured the temporal changes in defense enzyme activities and defense compounds in Eucalyptus under conditions of pest-feeding and leaf-clipping stresses, aiming to provide a theoretical basis for resistance breeding in Eucalyptus. The results show that pest-feeding and leaf-clipping stress groups significantly affected the peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) activities in Eucalyptus leaves. Within a short period after stress (3 h), POD activity was significantly reached 444.83 U by leaf-clipping stress, whereas it was significantly inhibited (34.83 U) by pest-feeding stress. PPO activity was significantly enhanced to 95.25 U under pest-feeding stress within 3 h, while leaf clipping induced a lower level of PPO activity (58.75 U). PAL activity was significantly induced to 474.38 U by leaf-clipping stress at 3 h, whereas pest-feeding stress resulted in a moderate increase to 238.00 U. Both pest-feeding and leaf-clipping stresses had significant effects on the contents of defense compounds in Eucalyptus leaves. Within a short period (3 h), both leaf-clipping and pest-feeding stresses significantly induced the accumulation of salicylic acid (0.226 μg/g and 0.326 μg/g, respectively), jasmonic acid (0.239 μg/g and 0.278 μg/g, respectively), and tannin (0.581 μg/g and 0.657 μg/g, respectively). The POD activity and salicylic acid content were identified as the primary factors in Eucalyptus responses to pest-feeding and leaf-clipping stresses. In conclusion, biotic (pest-feeding) and abiotic (leaf-clipping) stresses can induce higher activities of related defense enzymes while also promoting the synthesis of greater quantities of defensive chemical compounds, thereby enhancing the resilience to biotic and abiotic stresses in Eucalyptus. This study provides important practical guidance for insect-resistant Eucalyptus breeding and implementing integrated pest management strategies. Full article

Castanopsis hystrix (C. hystrix) is one of the most dominant and ecologically important species in subtropical evergreen broad-leaved forests of China. Interactions between its root and rhizosphere microorganisms play a pivotal role in nutrient acquisition and in mediating plant response s to environmental stresses. In this study, high-throughput 16S ribosomal RNA (16S rRNA) sequencing combined with untargeted metabolomics was employed to systematically characterize the rhizosphere microbial community and root exudates in C. hystrix. The results showed that, compared with non-rhizosphere soil, bacterial diversity in the rhizosphere of C. hystrix was significantly reduced, while several specialized and potentially efficient taxa were selectively enriched, particularly Candidatus_Solibacter, Candidatus_Xiphinematobacter, and Candidatus_Koribacter, thereby reshaping a distinct rhizosphere-specific community structure. Metabolomic analyses further revealed that 129 metabolites were significantly enriched in the rhizosphere, including four major classes of compounds associated with plant stress resistance: lipids and lipid-like molecules, organoheterocyclic compounds, organic acids and derivatives, and phenylpropanoids and polyketides. The enrichment of these metabolites likely contributes substantially to stress tolerance in C. hystrix. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis identified six defense-related metabolic pathways, including pyrimidine metabolism, steroid biosynthesis, nucleotide metabolism, plant hormone signal transduction, ATP-binding cassette transporter (ABC transporters), and the biosynthesis of various plant secondary metabolites. Further correlation analysis and co-occurrence network analysis suggested that C. hystrix may potentially influence the enrichment of beneficial microorganisms through rhizosphere metabolites selectively, which could reduce the reliance on external nutrient acquisition and enhance the stress resilience of C. hystrix. Our study provides a comprehensive perspective for elucidating rhizosphere interaction networks and their ecological functions in C. hystrix, thereby enhancing our understanding of the environmental adaptability of dominant tree species in subtropical forests. Full article

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (Fon), severely restricts the sustainable development of the global watermelon industry. While conventional chemical fungicides of this disease have triggered prominent ecological issues, Bacillus-based microbial biocontrol, which combines inherent environmental compatibility with stable control efficacy, has emerged as a key green alternative to chemical management. However, the biocontrol potential of Bacillus sonorensis against this disease has not yet been fully investigated. In this study, we isolated 56 bacterial strains from healthy watermelon rhizosphere soil, and obtained a Fon-antagonistic strain A-5 with the strongest activity (70.15% mycelial inhibition rate), which was identified as B. sonorensis via polyphasic taxonomic analysis. In vitro assays showed that the sterile fermentation filtrate of strain A-5 had a maximum 81.05% inhibition rate against Fon, and its volatile organic compounds also significantly suppressed Fon growth, with broad-spectrum antifungal activity against four common phytopathogenic fungi. Functional tests confirmed that strain A-5 could secrete cell wall-degrading enzymes, produce siderophores and synthesize indole-3-acetic acid, and 17 antimicrobial secondary metabolite biosynthetic gene clusters were identified in its genome. Pot experiments verified that strain A-5 had a 78.04% relative control efficacy against watermelon Fusarium wilt, which significantly reduced seedling disease incidence and upregulated defense-related antioxidant enzyme activities in watermelon leaves. In general, B. sonorensis A-5 is a promising novel biocontrol agent for green management of watermelon Fusarium wilt. Full article

The purpose of this study was to assess the effectiveness of two nanostructures (MgO and Zn/MgO) against Sclerotinia sclerotiorum, which causes white mold disease in peas, as direct antifungal agents or resistance inducers in pea plants. The direct antifungal activity of these nanostructures was evaluated by assessing their ability to inhibit S. sclerotiorum growth in vitro and reduce white mold severity in the greenhouse. The induction of resistance in pea plants was examined by assessing the expression of three defense-related genes using quantitative real-time PCR and measuring the phenolic compounds content in treated pea plants relative to untreated controls. The effect of the tested control agents on the growth and yield of pea plants was investigated. In comparison to the untreated control, S. sclerotiorum growth was markedly suppressed following treatment with the investigated compounds. The complete suppression (100%) of S. sclerotiorum growth was achieved with concentration levels of 100 mg/L for both MgO and Zn/MgO nanostructures. In greenhouse conditions, pea plants treated with the investigated chemicals showed a considerable reduction in the severity of white mold disease when compared to the untreated control plants. The transcript levels of 12-oxophytodienoate reductase 11 (OPR1), antioxidant peroxide (PsOXII), and chlorophyll a-b binding protein genes increased significantly in treated plants with MgO (3.1, 2.7, and 3.5-fold), fungicide (3.2, 2.8, and 2.8-fold), and Zn/MgO (3.5, 3, and 5-fold) compared to control, respectively. Pea plants treated with the tested nanoparticles generated more phenolic content than untreated controls. The application of fungicide and tested nanoparticles to peas greatly enhanced their growth properties. In light of our results, the application of these nanoparticles may represent a novel approach for controlling this pathogen. Full article

The aroma quality of grape fruit is a crucial trait for table grapes, yet its relationship with plant disease resistance remains unclear. Using ‘Shine Muscat’ grapes as material, this study employed HS-SPME-GC-MS combined with odor activity value (OAV) and PLS-DA analysis to investigate the regulatory effects of different rootstocks and GA₃/MeJA treatments on volatile aroma compounds. Linalool and α-terpineol were selected as representative compounds for antibacterial experiments and gene expression analysis of terpenoid synthesis. Results indicate that the Lot rootstock and 15.25 mg·L⁻¹ GA₃ treatment significantly promoted the accumulation of terpenoid aroma compounds. Linalool exhibited significant inhibitory effects on the mycelial growth of Colletotrichum fructicola and induced upregulation of DXS, TPS56, and TPS gene expression. This study reveals a potential link between aroma metabolism and defense responses, providing a theoretical basis for synergistic optimization of grape aroma quality improvement and disease-resistant cultivation. Full article

Background/Objectives: The valorization of bioactive compounds from food industry by-products aligns with sustainable development goals and represents a strategy for obtaining functional ingredients. Hazelnut (Corylus avellana L.) skins are a phenolic-rich residue with high antioxidant potential, but their extraction conditions and cellular mechanisms of action remain insufficiently explored. Methods: Ultrasound-assisted extraction was optimized using a 3³ Full Factorial Design (FFD) by investigating temperature (30–50–70 °C), extraction time (1–2–3 h), and solvent composition (water/ethanol). Antioxidant activity was evaluated using multiple in vitro assays, including Total Phenolic Content (TPC), DPPH, ABTS, FRAP, and β-carotene bleaching (BCB) assays. The optimized extract (OE) was chemically characterized by UHPLC–MS/MS and its activity was evaluated in HepG2 cells for biocompatibility, modulation of intracellular ROS levels, and antioxidant pathway activation. Results: Optimal extraction conditions were identified as 30 °C, 70.86 min (1.181 h), and 21.13% ethanol (v/v), yielding an extract with enhanced antioxidant capacity. UHPLC–MS/MS analysis revealed 25 bioactive compounds, mainly flavonoids and phenolic acids, relevant for oxidative stress modulation. The extract significantly reduced tert-butyl hydroperoxide (TBH)-induced intracellular ROS levels, restoring antioxidant proteins involved in the Nuclear Factor erythroid 2-related factor 2 (NRF-2)-mediated defense pathway. Conclusions: The optimized hazelnut skin extract combines strong antioxidant efficacy with cellular compatibility, supporting its potential application as a functional ingredient for nutraceutical and pharmaceutical strategies targeting oxidative stress-related conditions. Full article

The cultivation of asparagus (Asparagus officinalis L.) is plagued by two serious issues: “asparagus decline” and “asparagus replant problem”. The average lifespan of an asparagus plant is 15 to 20 years. However, its productivity decreases after a few years (asparagus decline). Even when these asparagus plants are replaced with new ones, the new plants remain unproductive (asparagus replant problem). The main causes of these problems are a Fusarium infection and asparagus autotoxicity. Several reviews have been conducted on Fusarium. Despite the accumulation of evidence on asparagus autotoxicity in the literature over the past four decades, no review has focused specifically on asparagus autotoxicity. It has been reported that asparagus growth is inhibited by asparagus root residues, leachates, root exudates, and rhizosphere soils. Several phenylpropanoids, including trans-cinnamic acid, p-coumaric acid, caffeic acid, and ferulic acid, have been identified as asparagus autotoxic substances in these root residues, root exudates, rhizosphere soils, growth media, and/or plant tissues. Tryptophan, 3,4-methylenedioxycinnamic acid, and iso-agatharesinol were also identified as asparagus autotoxic substances. These substances may cause autotoxicity by disrupting phytohormone levels, cellular metabolism, impairing membrane function, and by inducing oxidative stress. Although cinnamic, p-coumaric, caffeic, and ferulic acids have been reported to act as antibiotics, these compounds have also been shown to weaken the defense mechanisms of asparagus against pathogen infection, and enhance the Fusarium pathogenicity. The presence of these autotoxic substances, coupled with a Fusarium infection, may create a vicious cycle that worsens “asparagus decline” and “asparagus replant problem”. This is the first review to focus on the asparagus autotoxicity. Full article

Climate change is intensifying winters in temperate regions, posing a serious threat to Apis mellifera health. The gut microbiome, a distinct community of core bacterial species, is central to overwintering success by supporting immune function, nutrient assimilation, and pathogen resistance, but is highly sensitive to environmental stressors such as cold temperatures and dietary shifts. Stress-induced perturbations can reshape the composition and relative abundance of the gut microbiome in honey bees, leading to adverse effects on host health, physiological functions, and overwinter survival. Cold temperatures and additional stressors further destabilize the microbiome, compounding these effects. This review is the first to synthesize current knowledge on how extrinsic factors, such as diet, antibiotics, and pathogens, and intrinsic factors, including age and strain, influence the composition and function of the honey bee gut microbiota during the overwintering period. Given the increasing severity of winter conditions under climate change, a deeper understanding of microbiome–host–environment interactions is essential for improving honey bee resilience. By integrating evidence on the microbiome’s roles in nutrient utilization, immune modulation, and pathogen defense, this review outlines a framework to guide future research aimed at sustaining pollinator health and nutrition in a changing global climate. Full article