Search Results (499)

Plants are frequently exposed to a range of abiotic stresses, including drought, salinity, extreme temperatures, and heavy metals, that severely impair their growth and productivity. Among the adaptive mechanisms that plants have evolved, the accumulation of glycine betaine (GB), a naturally occurring, zwitterionic, and chemically stable osmoprotectant, has been widely recognized as a key strategy for stress tolerance. In higher plants, GB is primarily synthesized via the two-step oxidation of choline, catalyzed by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). GB contributes to cellular homeostasis by modulating osmotic balance, regulating ion flux, scavenging reactive oxygen species (ROS), enhancing antioxidant defense systems, and stabilizing proteins and membrane structures. Both exogenous application of GB and genetic engineering approaches aimed at enhancing endogenous GB biosynthesis have been shown to significantly improve plant tolerance to a variety of abiotic stresses. In this review, we provide a comprehensive overview of recent advances in the understanding of GB biosynthesis, its regulatory mechanisms, and its multifaceted roles in plant stress responses. We also highlight emerging prospects for leveraging GB-centered strategies to enhance crop resilience in challenging environmental conditions. Full article

As chemical messengers, phytohormones can enhance the tolerance of plants to stress caused by toxic elements (TEs) such as cadmium (Cd), lead (Pb), and zinc (Zn). This study investigated the combined toxicity of Cd, Pb, and Zn, and its impact on stress phytohormones (jasmonates, salicylic acid, and abscisic acid), in oat (Avena sativa L.) using anthropogenically contaminated soil in a 4-week pot experiment. The uptake of TEs by the roots increased in the multi-contaminated soil, while Zn was the only TE to be translocated to the leaves. The toxic effect of the TEs was assessed in terms of plant growth, revealing a decline in leaf dry biomass, whereas the impact on the roots was insignificant. These findings align with the levels of stress phytohormones. An increase in bioactive forms of stress phytohormones in leaves due to TEs indicates TE toxicity and leaf sensitivity. Conversely, low levels of these phytohormones, along with crosstalk between them, suggest reduced defense against TEs in the roots. The abundance of stress phytohormones declined in the following order: salicylic acid > jasmonates > abscisic acid. These results help to understand the mechanism by which plants respond to TEs, particularly their combined toxicity. Full article

Disease caused by Plasmodiophora brassicae severely disrupts cruciferous crops by altering root physiology and rhizosphere ecology. While pathogen-induced shifts in rhizosphere microbiomes are documented, the mechanisms linking root exudate reprogramming to microbial community remodeling remain poorly understood. Here, we integrated untargeted metabolomics and 16S rRNA sequencing to investigate how root exudates reshape the rhizosphere microbiome of tumorous stem mustard (Brassica juncea var. tumida) through P. brassicae infection. Metabolomic profiling identified 1718 root exudate metabolites, with flavones (e.g., apigenin 7-O-β-D-rutinoside, VIP > 1.5) and phenolic derivatives (e.g., gastrodin) being selectively enriched in infected plants. P. brassicae infection significantly increased rhizobacterial richness (ACE index, p < 0.05) and restructured the community composition, marked by enrichment of Paenibacillus (LDA score > 3.0). Procrustes analysis revealed tight coupling between microbial community shifts and metabolic reprogramming (M² = 0.446, p = 0.005), while Spearman correlations implicated pathogen-induced metabolites like geniposidic acid in recruiting beneficial Paenibacillus. Our results reveal that plant hosts dynamically secrete defense-related root metabolites to remodel the rhizosphere microbiome in response to P. brassicae infection. This dual-omics approach elucidates a chemical dialogue mediating plant–microbe–pathogen interactions, offering novel insights for engineering disease-suppressive microbiomes through root exudate manipulation. Full article

Rice (Oryza sativa L.) is a staple crop for over half of the global population; however, pathogenic infections pose significant threats to its sustainable production. Although chemical pesticides are commonly employed for disease control, their prolonged usage has led to pathogen resistance, reduced effectiveness, and non-target toxicity, rendering them unsustainable for agricultural practices. Nanomaterials (NMs) present a promising alternative due to their small size, tunable release properties, and diverse mechanisms for disease resistance. This review examines how NMs can enhance rice disease management through (1) direct pathogen suppression; (2) the activation of plant defense pathways; (3) the formation of nanoscale barriers on leaves to obstruct pathogens; (4) targeted delivery and controlled release of fungicides; and (5) modulation of the microbiome to bolster resilience. Moreover, we critically analyze the agricultural potential and environmental implications of NMs, develop optimized application strategies, and, for the first time, propose the innovative ‘NMs-Rice-Soil’ Ternary System framework. This groundbreaking approach integrates nanotechnology, plant physiology, and soil ecology. The pioneering framework offers transformative solutions for sustainable crop protection, illustrating how strategically engineered NMs can synergistically enhance rice productivity, grain quality, and global food security through science-based risk management and interdisciplinary innovation. Full article

Antipredator behaviors in animals often vary with developmental stage, microhabitat, and social context, yet few studies examine how these factors interact in species that undergo ontogenetic shifts in chemical defense. The spotted lanternfly (Lycorma delicatula) is an invasive planthopper whose nymphs transition from cryptically colored early instars to aposematically colored fourth instars that feed primarily on chemically defended host plants. We conducted 1460 simulated predator attacks on nymphs across four developmental stages to examine how antipredator behavior varies with instar, plant location (leaf vs. stem), host plant species, and local conspecific density. Nymphs exhibited three primary responses: hiding, sidestepping, or jumping. We found that location on the plant had the strongest effect, with nymphs on stems more likely to hide than those on leaves. Older instars were significantly less likely to hide and more likely to sidestep, particularly on stems, suggesting reduced reliance on energetically costly escape behaviors as chemical defenses accumulate. First instars were less likely to jump from their preferred host plant (tree of heaven) compared to other plant species. Higher local conspecific density reduced hiding probability, likely due to the dilution effect. These results demonstrate that antipredator strategies in L. delicatula are flexibly deployed based on developmental stage, microhabitat structure, and social context, with implications for understanding evolution of antipredator behavior in chemically protected species. Full article

The extensive use of pesticides has significant implications for public health and the environment. Breeding crop plants is the most effective and environmentally friendly approach to improve the plants’ resistance. However, it is time-consuming and costly, and it is sometimes difficult to achieve satisfactory results. Plants induce defense responses to natural elicitors by interpreting multiple genes that encode proteins, including enzymes, secondary metabolites, and pathogenesis-related (PR) proteins. These responses characterize systemic acquired resistance. Humic substances trigger positive local and systemic physiological responses through a complex network of hormone-like signaling pathways and can be used to induce biotic and abiotic stress resistance. This study aimed to assess the effect of humic substances on the activity of phenylalanine ammonia-lyase (PAL), peroxidase (POX), and β-1,3-glucanase (GLU) used as a resistance marker in various plant species, including orange, coffee, sugarcane, soybeans, maize, and tomato. Seedlings were treated with a dilute aqueous suspension of humic substances (4 mM C L⁻¹) as a foliar spray or left untreated (control). Leaf tissues were collected for enzyme assessment two days later. Humic substances significantly promoted the systemic acquired resistance marker activities compared to the control in all independent assays. Overall, all enzymes studied in this work, PAL, GLUC, and POX, showed an increase in activity by 133%, 181%, and 149%, respectively. Among the crops studied, citrus and coffee achieved the highest activity increase in all enzymes, except for POX in coffee, which showed a decrease of 29% compared to the control. GLUC exhibited the highest response to HS treatment, the enzyme most prominently involved in increasing enzymatic activity in all crops. Plants can improve their resistance to pathogens through the exogenous application of HSs as this promotes the activity of enzymes related to plant resistance. Finally, we consider the potential use of humic substances as a natural chemical priming agent to boost plant resistance in agriculture Full article

Polyvinyl chloride (PVC) is commonly employed as mulch in agriculture to boost crop yields. However, its toxicity is often overlooked. Due to its chemical stability, resistance to degradation, and the inadequacy of the recycling system, PVC tends to persist in farm environments, where it can decompose into microplastics (MPs) or nanoplastics (NPs). The radish (Raphanus sativus L.) was chosen as the model plant for this study to evaluate the underlying toxic mechanisms of PVC NPs on seedling growth through the integration of multi-omics approaches with oxidative stress evaluations. The results indicated that, compared with the control group, the shoot lengths in the 5 mg/L and 150 mg/L treatment groups decreased by 33.7% and 18.0%, respectively, and the root lengths decreased by 28.3% and 11.3%, respectively. However, there was no observable effect on seed germination rates. Except for the peroxidase (POD) activity in the 150 mg/L group, all antioxidant enzyme activities and malondialdehyde (MDA) levels were higher in the treated root tips than in the control group. Both transcriptome and metabolomic analysis profiles showed 2075 and 4635 differentially expressed genes (DEGs) in the high- and low-concentration groups, respectively, and 1961 metabolites under each treatment. PVC NPs predominantly influenced seedling growth by interfering with plant hormone signaling pathways and phenylpropanoid production. Notably, the reported toxicity was more evident at lower concentrations. This can be accounted for by the plant’s “growth-defense trade-off” strategy and the manner in which nanoparticles aggregate. By clarifying how PVC NPs coordinately regulate plant stress responses via hormone signaling and phenylpropanoid biosynthesis pathways, this research offers a scientific basis for assessing environmental concerns related to nanoplastics in agricultural systems. Full article

Knowing the superior biochemical defense mechanisms of sessile organisms, it is not hard to believe the cure for any human sickness might be hidden in nature—we “just” have to identify it and make it safely available in the right dose to our organs and cells that are in need. For decades, green tea catechins (GTCs) have been a case in point. Because of their low redox potential and favorable positioning of hydroxyl groups, these flavonoid representatives (namely, catechin—C, epicatechin—EC, epicatechin gallate—ECG, epigallocatechin—EGC, epigallocatechin gallate—EGCG) are among the most potent plant-derived (and not only) antioxidants. The proven anti-inflammatory, neuroprotective, antimicrobial, and anticarcinogenic properties of these phytochemicals further contribute to their favorable pharmacological profile. Doubtlessly, GTCs hold the potential to “cope” with the majority of today‘s socially significant diseases, yet their mass use in clinical practice is still limited. Several factors related to the compounds’ membrane penetrability, chemical stability, and solubility overall determine their low bioavailability. Moreover, the antioxidant-to-pro-oxidant transitioning behavior of GTCs is highly conditional and, to a certain degree, unpredictable. The nanoparticulate delivery systems represent a logical approach to overcoming one or more of these therapeutic challenges. This review particularly focuses on the lipid-based nanotechnologies known to be a leading choice when it comes to drug permeation enhancement and not drug release modification nor drug stabilization solely. It is our goal to present the privileges of encapsulating green tea catechins in either vesicular or particulate lipid carriers with respect to the increasingly popular trends of advanced phytotherapy and functional nutrition. Full article

Microbial biofilms present a formidable challenge in ophthalmology. Their intrinsic resistance to antibiotics and evasion of host immune defenses significantly complicate treatments for ocular infections such as conjunctivitis, keratitis, blepharitis, and endophthalmitis. These infections are often caused by pathogens, including Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, particularly in patients using contact lenses or intraocular implants—devices that serve as surfaces for biofilm formation. The global rise in antimicrobial resistance has intensified the search for alternative treatment modalities. In this regard, plant-derived antimicrobials have emerged as promising candidates demonstrating broad-spectrum antimicrobial and antibiofilm activity through different mechanisms from those of conventional antibiotics. These mechanisms include inhibiting quorum sensing, disrupting established biofilm matrices, and interfering with microbial adhesion and communication. However, the clinical translation of phytochemicals faces significant barriers, including variability in chemical composition due to environmental and genetic factors, difficulties in standardization and reproducibility, poor water solubility and ocular bioavailability, and a lack of robust clinical trials evaluating their efficacy and safety in ophthalmic settings. Furthermore, regulatory uncertainties and the absence of unified guidelines for approving plant-derived formulations further hinder their integration into evidence-based ophthalmic practice. This review synthesizes the current knowledge on the pathogenesis and treatment of biofilm-associated ocular infections, critically evaluating plant-based antimicrobials as emerging therapeutic agents. Notably, resveratrol, curcumin, abietic acid, and selected essential oils demonstrated notable antibiofilm activity against S. aureus, P. aeruginosa, and C. albicans. These findings support the potential of phytochemicals as adjunctive or alternative agents in managing biofilm-associated ocular infections. By highlighting both their therapeutic promise and translational limitations, this review contributes to the ongoing discourse on sustainable, innovative approaches to managing antibiotic-resistant ocular infections. Full article

Essential oils are lipophilic secondary metabolites produced in various parts of aromatic plants and stored in specialized secretory structures. They play a vital role in plant defense, offering protection against microorganisms and herbivores. These oils are known for a wide range of biological activities, including antibacterial, anti-inflammatory, antitumor, analgesic, antioxidant, and immunomodulatory effects. Given the increasing interest in natural alternatives to synthetic drugs, this review explored the therapeutic relevance of Pinus-derived essential oils as promising candidates in modern phytotherapy. Species of the genus Pinus have been widely investigated for their phytochemical composition and biological potential, with a focus on their medicinal and pharmaceutical applications. This review aimed to assess the biological properties of Pinus species commonly used in traditional medicine. In this paper, thorough insight into the chemical composition, as well as into the antimicrobial and antioxidant activities of essential oils obtained from the different parts of Pinus species, was given. Although recognized for their antimicrobial activity against a wide range of bacterial strains, including both Gram-positive and Gram-negative bacteria, the practical application of Pinus essential oils is often limited by their physicochemical instability and volatility. Therefore, this review highlighted the advances in formulation strategies, particularly encapsulation techniques, as the possible direction of future research concerning essential oils. Full article

The application of non-thermal (cold) plasmas is considered an environmentally friendly method that could affect plant metabolism and cellular development or can be used for the commercial production of natural products that cannot be chemically synthesized. In the present study, the non-embryogenic callus of iris (Iris reichenbachii Heuff.) was treated with a Radio Frequency (RF) plasma needle device using He as a working gas. We investigated short-term (up to seven days) and long-term (up to one year) changes on morphological, physiological and biochemical levels. An increased production of O₂⁻ and H₂O₂ was observed in the callus tissue after plasma treatment. The enzymes SOD and CAT represented the frontline in the antioxidant defense against reactive oxygen species (ROS) produced during the first hour of treatment, while POX was the leading antioxidant enzyme seven days after plasma treatment. Significant long-term morphological changes were observed in the calli due to the increased mitotic activity of the plant cells. In addition, three flavonoids (naringenin, apigenin and acacetin) and two isoflavonoids (irisolidone and irilone) were detected only in the plasma-treated tissue even one year after plasma treatment. The present study emphasizes the application of the plasma technique to promote meristematic activity and stimulate the production of specialized metabolites in iris calli. Full article

Traditional medicinal plants are valued for their therapeutic potential, yet the full spectrum of their bioactive compounds often remains underexplored. Recent advances in multiomics technologies, including metabolomics, proteomics, and transcriptomics, combined with in vitro culture systems and elicitor-based strategies, have revolutionized our ability to characterize and enhance the production of valuable secondary metabolites. This review synthesizes current findings on the integration of these approaches to help us understand phytochemical pathways optimising bioactive compound yields. We explore how metabolomic profiling links chemical diversity with antioxidant and antimicrobial activities, how proteomic insights reveal regulatory mechanisms activated during elicitation, and how in vitro systems enable controlled manipulation of metabolic outputs. Both biotic and abiotic elicitors, such as methyl jasmonate and salicylic acid, are discussed as key triggers of phytochemical defense pathways. Further, we examine the potential of multiomics-informed metabolic engineering and synthetic biology to scale production and discover novel compounds. By aligning traditional ethnobotanical knowledge with modern biotechnology, this integrative framework offers a powerful avenue to unlock the pharmacological potential of medicinal plants for sustainable and innovative therapeutic development. Full article

With the sustainable increase in agricultural productivity, the need for safer, environmentally friendly pesticide alternatives is also growing. Metabolites of microorganisms (bacteria, fungi, actinomycetes) are emerging as potential bioactive compounds for integrated pest and disease management. These compounds comprise amino acids, carbohydrates, lipids, organic acids, phenolics, peptides, alkaloids, polyketides, and volatile organic compounds. The majority of them have insecticidal, fungicidal, and nematicidal activities. In this review, the classifications, biosynthetic pathways, and ecological functions of primary and secondary metabolites produced by microorganisms are discussed, including their mechanisms of action, ranging from competition to systemic acquired resistance in host plants. The article highlights the importance of microbial genera (viz., Bacillus sp., Pseudomonas sp., Trichoderma sp., Streptomyces sp., etc.) in making chemicals and biopesticides for crop defense. We present the possible applications of microbial biosynthesis strategies and synthetic biology tools in bioprocess development, covering recent innovations in formulation, delivery, and pathway engineering to enhance metabolite production. This review emphasizes the significance of microbial metabolites in improving the plant immunity, yield performance, reduction in pesticide application, and the sustainability of an ecological, sustainable, and resilient agricultural system. Full article

The fungus Alternaria alternata, which causes tobacco brown spot disease, poses a serious threat to the tobacco industry. Beneficial microorganisms and their secondary metabolites have emerged as a promising green strategy for disease management. This study recovered 16 endophytic bacterial strains from Mentha haplocalyx Briq., a therapeutic herb. The study revealed that strain B5, with an inhibition rate of 82.76%, exhibited the highest antifungal activity against A. alternata. This strain exhibited broad-spectrum antifungal activity, with inhibition rates ranging from 66.34% to 87.23%. Phylogenetic analysis of 16S rDNA and gyrA gene sequences identified it as Bacillus velezensis (GenBank: PV168970 and PV173738). Further characterization revealed that strain B5 can secrete cell wall-degrading enzymes, produce IAA, and synthesize siderophores. The growth of mycelium in A. alternata was greatly reduced by both the ethyl acetate extract and the filtered liquid from the sterile fermentation, resulting in marked morphological abnormalities. Multiple antifungal active substances were identified through liquid LC-MS analysis. Greenhouse experiments demonstrated that the B5 fermentation broth effectively suppressed the occurrence of tobacco brown spot disease, achieving a relative control efficacy of 60.66%, comparable to that of 10% difenoconazole water dispersible granule (WDG). Additionally, strain B5 enhances plant disease resistance by activating the activities of key defense enzymes. B. velezensis B5 serves as a safe alternative to chemical fungicides and is highly effective at controlling tobacco brown spot disease. Full article

Blackleg disease poses a major threat to global canola production. The resistance gene Rlm1, corresponding to the avirulence gene AvrLm1 in the pathogen Leptosphaeria maculans, has been widely used to mitigate the impact of the disease. To investigate the biochemical basis of Rlm1-mediated resistance against blackleg, we conducted an LC-MS–based analysis of a susceptible Topas double haploid (DH) line and its isogenic Rlm1-carrying resistant counterpart for metabolomic profiles during the infection process. Samples were labeled with ¹²C- and ¹³C for LC-MS analyses to enhance both chemical and physical properties of metabolites for improved quantification and detection sensitivity. Resistant plants showed early and sustained accumulation of several defense metabolites, notably pipecolic acid (PA, up to 326-fold), salicylic acid (SA), and gentisic acid (GA) in L. maculans-inoculated Topas–Rlm1 plants compared to mock-inoculated Topas–Rlm1 controls (adjusted p < 0.05), indicating activation of lysine degradation and hormonal defense pathways. Elevated glucosinolates (GLS), γ-aminobutyric acid (GABA), and melatonin precursors may further contribute to antimicrobial defense and cell-wall reinforcement. In contrast, flavonoid and phenylpropanoid pathways were down-regulated, suggesting metabolic reallocation during resistance. Exogenous application of PA, SA, GA, ferulic acid, and piperonylic acid (a known inhibitor of the phenylpropanoid pathway in plants) significantly reduced infection in susceptible canola varieties, validating their defense roles against blackleg. These results offer new insights into Rlm1-mediated resistance and support metabolic targets for breeding durable blackleg resistance in canola. Full article