Search Results (1,262)

Phosphorus (P) deficiency is a major constraint on crop productivity, and rapeseed (Brassica napus L.) is particularly sensitive to low phosphorus (LP) stress, yet the role of salicylic acid (SA) in alleviating LP stress in this crop remains poorly understood. Here, we investigated how exogenous SA alleviates LP stress in rapeseed seedlings. SA was applied at 0.1 mM and 0.2 mM under LP conditions, and its effects on plant growth, physiological traits, and transcriptomic responses were evaluated. SA treatment significantly ameliorated LP-induced growth inhibition, increased chlorophyll content and peroxidase activity, and reduced superoxide anion accumulation. RNA-seq analysis revealed that SA up-regulated the expression of phosphate transporter (PHT) family genes and activated genes involved in nitric oxide biosynthesis, flavonoid biosynthesis, glutathione metabolism, and nitrogen metabolism. These findings indicate that SA enhances LP tolerance in rapeseed through coordinated regulation of phosphorus acquisition, antioxidant defense, and key metabolic pathways, highlighting the potential of exogenous SA as an approach that could be further explored to improve phosphorus use efficiency under phosphorus-limited conditions in controlled environments, with field validation still needed. Full article

Salt stress is one of the main abiotic stress factors affecting plant growth and development. Acetylcholine (ACh) is a potential signaling molecule involved in plant stress resistance and growth, but its role in grapevine stress tolerance remains poorly understood, largely because its exogenous application has not been investigated in grapevines. In this study, we found that 40 μmol/L ACh significantly alleviated salt stress induced by 200 mM NaCl in the Vitis hybrid ‘Summer Black’ (V. vinifera × V. labrusca). Exogenous application of ACh significantly improved plant growth under salt stress, including plant height, stem diameter, root fresh weight, and dry weight, while also increasing chlorophyll content and enhancing photosynthetic efficiency. Additionally, exogenous ACh substantially increased antioxidant enzyme activity and considerably reduced the accumulation of reactive oxygen species and malondialdehyde. Moreover, exogenous application of ACh decreased Na⁺ uptake and dramatically lowered relative electrical conductivity. Comparative transcriptomic analysis revealed that although salt stress repressed genes involved in photosynthesis and carbon fixation, ACh application effectively reversed this suppression by up-regulating transcriptional programs associated with photosystem, carbon metabolism, peroxisome and hormone signal transduction. Collectively, exogenous ACh enhances salt tolerance in grapevines, providing preliminary insights into ACh-mediated stress tolerance signaling in woody plants. Full article

The objective of this study was to investigate the effect of exogenous selenium on selenium enrichment and antioxidant activity of germinated chestnuts. We treated ‘Zaofeng’ chestnuts with Na₂SeO₃ at concentration of 0, 20, 40, 60 and 80 mg/L, and analyzed, during germination, the level of total Se, SeCys₂, MeSecys, Se^IV, SeMet, Se^VI, γ-aminobutyric acid (GABA), antioxidant enzyme (phenylalanine ammonialyase (PAL), glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT)) activity, non-enzymatic antioxidant substances (total polyphenols and flavonoids) content and antioxidant capacity (DPPH, ABTS). The results indicated that low concentrations of selenium (20–40 mg/L) significantly promoted the organic transformation of selenium, with a Se-enrichment rate over 74%. Antioxidant enzyme (PAL, SOD, CAT) activities and total phenol content were enhanced by 1.1 to 1.9-fold compared with the control, leading to a 12.2–29.2% improvement in antioxidant capacity (DPPH and ABTS). In contrast, the high concentration of selenium (80 mg/L) induced oxidative stress, inhibiting enzyme (PAL, SOD, CAT) activities (reduced by 14.1–20.5%) and decreasing antioxidant capacity (DPPH) by approximately 19.0%. During chestnut germination, selenite was absorbed by the embryo and subsequently transformed into organic Se in vivo, ultimately being stored mainly as SeCys₂. The selenium enrichment rate decreased significantly with increasing Na₂SeO₃ treatment concentration: from 86.4% at 20 mg/L to 62.2% at 80 mg/L. Furthermore, treatment with 40 mg/L Na₂SeO₃ led to a significant increase in GABA content of germinated chestnuts, reaching 1.3 times that of the control group. Overall, germination with 20–40 mg/L Na₂SeO₃ is an effective condition for producing Se-enriched chestnut sprouts with enhanced GABA and antioxidant capacity, offering a potential functional food ingredient. Full article

Excessive accumulation of reactive oxygen species from exogenous and endogenous stressors can cause cellular damage. Chlorella contains diverse bioactive compounds, and violaxanthin, a major carotenoid pigment found in Chlorella sp. HS-V, has been reported to possess anti-inflammatory, anticancer, and antioxidant properties. We investigated the effect of violaxanthin on hydrogen peroxide (H₂O₂)-induced oxidative stress in human keratinocytes. Chlorella sp. HS-V extract significantly restored the H₂O₂-induced decrease in cell viability. Similarly, violaxanthin reduced H₂O₂-induced cytotoxicity and intracellular reactive oxygen species levels, which was associated with the upregulation of antioxidant enzyme expression. Under H₂O₂-induced oxidative stress conditions, violaxanthin may enhance cellular antioxidant defense by promoting nuclear factor erythroid 2-related factor 2 (NRF2) translocation through the phosphoinositide 3-kinase/protein kinase B/glycogen synthase kinase 3β (PI3K/AKT/GSK3β) signaling pathway. Additionally, violaxanthin improved H₂O₂-impaired wound healing in HaCaT human keratinocyte cells and reduced senescence-associated beta-galactosidase-positive normal human epidermal keratinocytes. Overall, these findings suggest that violaxanthin may serve as a potential therapeutic agent for mitigating oxidative stress-induced cellular dysfunction. Full article

Soybean (Glycine max (L.) Merr.) is a globally crucial food crop and a model plant for studying symbiotic nitrogen fixation in legumes. Triacontanol (TRIA) is a natural plant growth regulator that enhances photosynthetic efficiency, stress tolerance, antioxidant enzyme activities and yield in crops. However, its regulatory role in nodulation and nitrogen fixation in legumes remains unclear. In this study, soybean seedlings inoculated with Bradyrhizobium japonicum strain USDA110 were treated with different concentrations of TRIA (0, 0.33, 0.5, 1 and 2 μg/mL). Then, oxidative stress indicators and comparative transcriptomic analysis were performed to check the oxidative status and screen the candidate genes under TRIA treatment. Our results showed that the 0.5 μg/mL TRIA treatment produced the greatest nodule number. TRIA treatment significantly induced antioxidant responses in soybean roots. Comparative transcriptome identified 867 differentially expressed genes (DEGs), Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses of DEGs revealed that a large number of genes were enriched in pathways related to oxidative activity. Combined with the expression pattern, we identified a Glutathione S-Transferase family gene, GmHSP26 (Glyma.07G139700), whose expression was induced by both TRIA and rhizobial infection, with its promoter activity was activated throughout the entire process of nodule development. Further function study using overexpression and gene editing proved that GmHSP26 was a positive regulator of soybean nodulation. Collectively, this study identifies the optimal TRIA concentration for promoting soybean nodulation, reveals the function and mechanism of GmHSP26 in response to TRIA-regulated nodulation, and provides a theoretical basis and genetic resource for enhancing nodulation and nitrogen fixation in leguminous crops through exogenous growth regulators. Full article

Light availability is a primary determinant of plant growth and a key factor influencing the success of alien plant invasions. Although the phytohormone abscisic acid (ABA) is a known master regulator of abiotic stress responses, its specific role in the shade tolerance and competitive advantage of invasive species remains poorly understood. In this study, we conducted a comparative experiment using the highly invasive Wedelia trilobata and its native congener, Wedelia chinensis. We investigated their eco-physiological responses to normal (100%) and low-light (30%) intensities, coupled with the application of exogenous ABA (A1) and the biosynthesis inhibitor sodium tungstate (S1). Our results showed that low light significantly inhibited the growth and photosynthetic capacity of both species, reducing biomass and net photosynthetic rate P_n. However, exogenous ABA application specifically enhanced the P_n and biomass of the invasive W. trilobata under low-light stress, while reducing malondialdehyde (MDA) content and optimizing antioxidant enzyme activities (SOD, POD, and CAT). Conversely, the inhibition of endogenous ABA by sodium tungstate exacerbated oxidative damage and photosynthetic decline in both species, with a more pronounced negative impact on W. trilobata. Correlation analysis further revealed that W. trilobata maintains a superior capacity to coordinate stomatal regulation and antioxidant defense through ABA signaling. These findings suggest that the invasive success of W. trilobata in fluctuating light environments is significantly driven by its high sensitivity and efficiency in ABA-mediated physiological plasticity, providing a potential target for managing its spread through hormonal or metabolic interference. Full article

Poor seed germination severely limits the propagation and conservation of Zelkova schneideriana (Chinese zelkova). However, the comparative effects of different exogenous phytohormones on seed germination of this species and the associated molecular responses remain insufficiently understood. To evaluate the effects of exogenous phytohormones on seed germination and to explore the underlying molecular basis, a germination experiment was conducted from January to March 2024 at Central South University of Forestry and Technology, Changsha, Hunan, China, in which seeds were treated with different concentrations of 6-benzylaminopurine (6-BA; 20, 40, and 80 mg/L), gibberellic acid (GA₃; 125, 250, and 500 mg/L), indole-3-acetic acid (IAA; 100, 200, and 300 mg/L), brassinolide (BR; 10, 20, and 30 mg/L), and abscisic acid (ABA; 50, 100, and 150 mg/L). Germination traits were assessed, and transcriptome sequencing was performed for the BR treatment showing the strongest promotive effect. The results demonstrate that exogenous hormones exerted distinct regulatory effects on seed germination, among which BR at 10 mg/L showed the strongest promotive effect, increasing the final germination rate at 40 d from 50% in the control to 68%, whereas higher concentrations caused inhibitory effects. Transcriptome analysis identified 169 differentially expressed genes between BR-treated seeds and the control, mainly associated with reactive oxygen species (ROS) metabolism, redox regulation, energy and carbohydrate metabolism, and plant hormone- and MAPK-related signaling pathways. Antioxidant enzyme assays showed that BR10 increased POD activity but decreased SOD, CAT, APX, and GR activities. Endogenous hormone-related analysis further revealed marked BL accumulation and significant decreases in ACC, GA₃, GA₄, IAA, JA, and SA. Overall, exogenous BR promotes seed germination of Z. schneideriana through coordinated physiological and molecular regulation, providing a useful basis for seed pretreatment and seedling propagation. Full article

In the context of the circular economy, the valorization of natural biomolecules from by-products has recently represented a major goal in health promotion. From this perspective, this study examined the antioxidant potential of Sicilian white grape pomace from the Pinot Gris variety, using subcritical water extraction as an eco-friendly and innovative method to recover bioactive compounds. Different extraction parameters allowed for comparing the potential of various fractions. Among these, the Subcritical Water Extract obtained after 5 min at 160 °C (SWE^160.1) was rich in gallic acid and protocatechuic acid, as evidenced by characterization with UHPLC-Q Exactive Orbitrap-HRMS system. SWE^160.1 showed efficacious antioxidant activity, as confirmed by DPPH assay and total polyphenol and flavonoid content. Interestingly, SWE^160.1 displayed cytotoxic activity in tumor cell lines, while preserving the viability of non-tumor bronchial epithelial cells. Specifically, SWE^160.1 protected these cells from exogenous oxidative stress, reducing the ROS levels and activating Nrf2-mediated antioxidant response. Surprisingly, upregulation of antioxidant enzymes (HO-1 and SOD-2) induced by SWE^160.1 was maintained in the presence of lipopolysaccharide, indicating a specific involvement of SWE^160.1 in the anti-inflammatory response. Finally, SWE^160.1 was also able to limit the formation of stress granules following acute stress, thereby supporting its potential to maintain cellular homeostasis. Overall, this study highlights the potential of grape pomace as a source of active molecules to prevent oxidative stress and inflammation. Full article

Plants are constantly exposed to a wide range of abiotic stresses that have significant negative impacts on growth and yield. Plant acclimation to these stresses is governed by integrated classical phytohormone and plant peptide hormone signalling networks that control the ability of a plant to survive and adapt to extreme environments. Classical phytohormones, including abscisic acid, auxins, gibberellins, cytokinins, jasmonates, salicylic acid, brassinosteroids, and the recently recognised phytomelatonin, act in concert with peptide-based plant hormones, among which C-terminally encoded peptides (CEPs) play prominent roles in coordinating stress perception, signal transduction, and adaptive responses throughout the plant. These integrated networks control stomatal behaviour, photosynthesis, osmolyte and antioxidant levels, root architecture, and energy metabolism, thereby helping plants maintain homeostasis and optimise survival while sustaining minimal growth under unfavourable conditions. Under stressful conditions, these networks do not operate in isolation but form highly dynamic, context-dependent regulatory circuits in which each physiological process is simultaneously regulated by multiple hormones acting through convergent and overlapping signalling pathways. Phytomelatonin has emerged as a particularly important integrative node within these networks, functioning both as a potent direct antioxidant through sequential ROS-scavenging catabolite cascades and as a bidirectional regulator of classical phytohormone signalling under diverse abiotic stresses. New technologies in the fields of transcriptomics, proteomics, phosphoproteomics, metabolomics, and systems biology have provided new information on the dynamic relationships between classical phytohormones and plant peptide hormones, revealing candidate regulatory nodes and transcription factor networks that mediate stress adaptation at molecular, biochemical, and physiological levels. However, it is important to distinguish between correlative associations identified through omics profiling and causal regulatory relationships validated through rigorous genetic and biochemical experimentation, as most omics-derived candidates remain to be functionally established. Empirical studies demonstrate how these networks can be used to improve crops by increasing stress tolerance through modulating classical phytohormone and plant peptide hormone signalling, including through exogenous phytomelatonin application, CRISPR-mediated hormone pathway editing, and CEP pathway manipulation, to produce resilient cultivars without reducing yields. Although these advances represent significant progress, challenges remain, including the inherent complexity and redundancy of the networks, context-dependence and severity-dependence of hormonal responses, the persistence of a significant translational gap between laboratory findings and field application, and incomplete mechanistic understanding of peptide hormone roles under combined stress conditions. Addressing these challenges will require integrative multi-omics approaches, higher-order computational modelling, and rigorous field-based functional validation alongside emerging tools such as synthetic biology and precision breeding. Full article

Low temperature severely constrains the growth and ecological application of submerged macrophytes in aquatic ecosystem restoration. Although brassinolide (BR) has been shown to alleviate abiotic stress in terrestrial plants, its role in submerged macrophytes remains poorly understood. This study investigated the effects of different BR concentrations (0, 0.05, 0.1, and 0.5 mg L⁻¹) on growth, photosynthesis, antioxidant defense, and osmotic adjustment in Hydrilla verticillata under low-temperature stress (2 °C) over 15 days. Exogenous BR significantly alleviated low-temperature-induced damage in H. verticillata in a concentration-dependent manner. Among all treatments, 0.05 mg L⁻¹ BR showed the strongest overall effect, increasing fresh weight, dry weight, and plant height by 16.22%, 22.67%, and 9.52%, respectively, compared with the control. It also promoted photosynthetic performance, with Fv/Fm and Y(II) increasing by 251.93% and 262.83%, respectively, on day 10, and enhanced stress resistance, as reflected by a 32.44% increase in SOD activity and a 112.59% increase in soluble sugar content on day 15. In contrast, higher BR concentrations (0.1 and 0.5 mg L⁻¹) were less effective overall. Membership function analysis ranked the treatments as 0.05 mg L⁻¹ (0.95) > 0.1 mg L⁻¹ (0.47) > 0.5 mg L⁻¹ (0.19) > 0 mg L⁻¹ (0.09). These results indicate that BR enhances low-temperature tolerance in H. verticillata through coordinated regulation of photosynthetic performance, antioxidant defense, and osmotic adjustment, providing a physiological basis for its application in submerged macrophyte restoration under low-temperature conditions. Full article

Drought frequently threatens the yield and quality of Carya cathayensis Sarg. cultivated in mountainous regions. To search for effective drought-resistant regulators is of great significance for alleviating short-term seasonal drought in C. cathayensis during dry seasons, thereby stabilizing its yield and quality. Silicon dioxide nanoparticles (SiO₂ NPs) mitigate abiotic stress in plants. To give insight into the regulatory role of SiO₂ NPs in mitigating drought stress, polyethylene glycol 6000 (PEG-6000) was used to simulate varying degrees of drought conditions, and the growth phenotype, photosynthetic physiological characteristics, antioxidant defense system, and cellular ultrastructure of C. cathayensis leaves were analyzed to evaluate the impacts of foliar-applied exogenous SiO₂ NPs. The results indicated that, compared with severe drought, 200 mg/L SiO₂ NP application to plants under severe drought treatment significantly increased superoxide dismutase and peroxidase activities and chlorophyll and nitrogen contents, while malondialdehyde levels decreased. Furthermore, SiO₂ NP application notably enhanced the net photosynthetic rate, stomatal conductance, and electron transport efficiency. This effectively alleviated both stomatal and non-stomatal limitations, thereby mitigating drought-induced photosynthetic inhibition. Additionally, Transmission electron microscopy revealed that SiO₂ NPs effectively preserved the structural integrity of chloroplasts, mitochondria, and nuclei, reducing drought-induced ultrastructural damage. In conclusion, exogenous SiO₂ NPs enhance drought tolerance in C. cathayensis by synergistically modulating photosynthesis, antioxidant defense, and cellular structural stability. Full article

Soil acidity is a major constraint in many agricultural regions, where increased aluminum (Al³⁺) solubility at low pH severely affects plant health by inhibiting root elongation, disrupting nutrient uptake, and inducing oxidative stress. Recent studies have highlighted melatonin, a widely occurring indoleamine with strong antioxidant and stress-modulating properties, which alleviates Al-induced damage in crops. This review synthesizes current physiological, biochemical, and agronomic evidence demonstrating that exogenous melatonin enhances plant tolerance to aluminum toxicity. Across multiple model and crop species, melatonin application has been shown to improve root elongation by 20–45%, reduce lipid peroxidation by 30–60%, and enhance key antioxidant enzymes such as SOD, POD, and CAT by 25–70% under Al stress. Case studies in soybean, wheat, maize, and rice further indicate that melatonin protects root meristems from oxidative damage, stabilizes photosynthetic machinery, and improves nutrient acquisition. In acidic soils (pH 4.5), melatonin-treated soybean exhibited 28% greater biomass and 15–22% higher N and P uptake, while wheat plants demonstrated 10–18% higher grain filling under field-simulated Al stress. Emerging long-term studies show that melatonin also benefits soil health. Multi season experiments reveal that melatonin enhances root exudates that support beneficial rhizosphere microbes, increases soil enzymatic activities (urease, phosphatase) by 20–35%, and lowers exchangeable Al by 12–18%. These improvements contribute to cumulative yield gains of 10–18% over successive cropping cycles. Additionally, genetic approaches aimed at increasing endogenous melatonin levels in plants have demonstrated 12–30% yield improvement in acid soil conditions. This review highlights the need for multi-year, multi-location studies to further clarify how melatonin can support sustainable agricultural practices, enhance soil fertility, and mitigate aluminum toxicity in acid-affected regions. Full article

(1) Background: Nitric oxide (NO) serves as a crucial signaling molecule in plant abiotic stress responses. Although its role in enhancing drought resistance in cotton has been recognized, the specific mechanisms underlying this physiological and molecular regulation remain largely unexplored. This study aims to elucidate the multi-layered mechanisms by which NO modulates drought resistance in cotton; (2) Methods: Cotton seedlings were subjected to drought stress with the application of the NO donor sodium nitroprusside (SNP). A combination of confocal laser scanning microscopy, transcriptional expression analysis, biochemical assay of enzyme activity, virus-induced gene silencing (VIGS), and in vitro protein modification assays was applied to characterize the effects of NO on the drought stress response in cotton; (3) Results: Exogenous NO significantly reinforced drought resistance in cotton seedlings by improving leaf water retention capacity and photosynthetic efficiency, eliminating excessive drought-induced reactive oxygen species (ROS), upregulating the transcription and enzymatic activity of antioxidant enzymes, and promoting stomatal closure. Mechanistically, NO triggered S-nitrosylation of the plasma membrane H⁺-ATPase isoform GhHA2, thereby enhancing its protein stability; (4) Conclusions: These findings reveal that exogenous NO orchestrates cotton drought tolerance via multiple interconnected physiological and molecular pathways, in which the activation of the antioxidant defense system and the modulation of stomatal closure serve as central regulatory mechanisms. Full article

Herein, we report a simple procedure regarding the photodynamic therapy (PDT) treatment as a minimally invasive modality for treating superficial bladder cancer that utilizes a photosensitizer, light, and oxygen to generate cytotoxic reactive oxygen species (ROS). This study evaluates the histopathological and morphological changes induced by PDT in an ex vivo model of low-grade (LG) pTa non-muscle-invasive bladder cancer (NMIBC). We investigated the efficacy of exogenous protoporphyrin IX (PpIX) and Rose Bengal (RB) by incubating tissue samples (n = 30) with an oxygen-saturated solution of PpIX (1–3 mM) or RB (0.3–0.5 mM) for one hour. Since the criticism of using frozen tissue in research already exists, this framing explains how to mitigate those limitations. Thus, we use oxygen-saturated solutions PpIX and oxygen-saturated solutions of RB. We discussed a few aspects related to the use of frozen tissue in PDT. Frozen tissue preserves lipids critical for assessing membrane damage and maintains higher levels of metabolic markers like antioxidant molecules like glutathione and more likely lack factors such as metabolic activity, intact cell membranes, and oxygenation. It is critical to differentiate between “artifactual” changes and the “pathological” death of cells. Thus, we used histopathological microscopy observation typically used in daily clinical investigations to characterize cells before and after PDT. Following irradiation with the light dose of 72 J/cm² (410 nm or 532 nm at 300 mW for 15 min), hematoxylin–eosin staining revealed concentration-dependent apoptotic changes, including chromatin condensation, pyknosis, and nuclear fragmentation. While both agents induced cell death, RB demonstrated faster and more intense cytotoxicity than PpIX. These findings provide microscopic evidence of PDT-induced tumor destruction and suggest that RB is a potent candidate for further preclinical evaluation. At 410 nm (deep blue/violet), light penetration in biological tissue is very shallow, typically only around 0.3 to 1 mm; therefore, in a 2 mm thick tissue sample, most of the light would be absorbed within the first millimeter, with minimal light reaching the full depth of tissues. In this protocol, the generated ROS is used to destroy tumor tissue by attacking the cellular microenvironment directly. This led to immediate membrane disruption and lipid peroxidation. The proof-of-concept is an early-stage study designed to verify that a PDT treatment is feasible, safe, and biologically active in an ex vivo model of LG pTa NMIBC. Full article

Globba bicolor Gagnep., an ornamental ginger of cultural importance in Thailand’s “Tak Bat Dok Mai” festival, faces conservation challenges due to climate change and slow natural propagation. Limited understanding of its cultivation and chemical composition further constrains sustainable utilization. This study provides the first integrated investigation of micropropagation using rhizome-derived explants under various combinations of exogenous hormones, acclimatization strategies, and comparative phytochemical profiling between wild and in vitro-propagated plants. An optimized clonal regeneration system was established from plantlets, with Murashige and Skoog (MS) medium containing 2.0 mg/L 6-benzylaminopurine (BA) and 0.5 mg/L 1-naphthaleneacetic acid (NAA), yielding the highest multiplication (9.10 shoots/explant and 12.40 roots/explant) after eight weeks of cultivation. During acclimatization, sand substrate proved superior, facilitating a 90% survival rate and enhanced physiological vigor. Comparative analysis revealed that while wild plants possessed significantly higher total phenolic (TPC) and total flavonoid (TFC) contents and antioxidant activities (DPPH, ABTS, and FRAP) than their in vitro counterparts, both sources maintained a rich diversity of chemical constituents. HPLC analysis identified cinnamic acid, rutin, and quercetin as major metabolites, while GC–MS detected 90 volatile compounds, with β-caryophyllene and β-pinene as predominant constituents. Notably, rhizomes of wild plants exhibited particularly high-value detections. To provide a rapid and non-destructive approach for linking chemical composition with antioxidant activity, FTIR-based chemometric models were applied, demonstrating high predictive accuracy (R²–cv = 0.9712–0.9862). These results provide a scientific foundation for the conservation and sustainable commercial utilization of G. bicolor as a potential source of bioactive natural products. Full article