Search Results (949)

Carotenoids contribute to photoprotection and abiotic stress adaptation in plants, and lycopene cyclases (LCYs) occupy a key branch point in carotenoid biosynthesis. However, the composition and stress-responsive divergence of LCY genes in pepper remain insufficiently characterized. In this study, we identified six CaLCY genes in Capsicum annuum and analyzed their structural features and expression patterns under drought and salt stress. CaLCYB1 showed the strongest and most consistent induction under both drought and salt stresses and was positively correlated with carotenoid accumulation, whereas the other CaLCY members exhibited distinct or negligible expression patterns. Transient overexpression of CaLCYB1 significantly increased β-carotene and total carotenoid contents by 117.6% and 45.1%, respectively, relative to the empty-vector control, and also augmented ABTS^•+ radical scavenging activity as well as ascorbate peroxidase (APX) activity. Conversely, virus-induced gene silencing (VIGS) of CaLCYB1 led to marked reductions in all of these parameters. Correlation analysis, together with gain- and loss-of-function assays, supports an important role of CaLCYB1 in carotenoid accumulation and β,β-branch-related antioxidant responses under stress. Yeast two-hybrid screening identified three potential interactors of CaLCYB1, namely CaUBQ, CaLHP1, and CaLARP6B. This study provides a family-level characterization of LCY genes in pepper and identifies CaLCYB1 as a major stress-responsive member that directs carotenoid flux and enhances antioxidant capacity under abiotic stress. Full article

The common bean (Phaseolus vulgaris L.cv. BR-104) is the most widely cultivated legume crop and serves as a major dietary protein source worldwide. However, climate change-induced drought poses a severe threat to its productivity by disrupting key physiological and biochemical processes. Therefore, identifying effective strategies to enhance drought resilience in the common bean is of considerable importance. The present study investigates the regulatory role of hydrogen sulfide (H₂S) in improving drought tolerance. Polyethylene glycol (15% PEG) induced drought stress markedly reduced phenotypic changes (leaf area (LA), plant dry weight (PDW), root length (RL), and shoot length (SL) by 18.6, 20.5, 30.3 and 17.5% respectively), photosynthetic efficiency (Fv/Fm by 28.4%), and photosynthetic pigment concentrations (chlorophyll and carotenoids by 25.6 and 36%, respectively), while significantly elevating oxidative stress markers (H₂O₂ and TBARS by 137.1% and 169.8%, respectively), leading to impaired stomatal movement and damaged chloroplast structure. Exogenous H₂S application as sodium hydrogen sulfide (200 µM NaHS; H₂S donor) effectively alleviated drought-induced oxidative damage by boosting endogenous H₂S and GSH levels, upregulating activity of antioxidative enzymes, SOD, APX, and GR, thereby promoting reactive oxygen species (ROS) scavenging, and minimizing lipid peroxidation. Moreover, H₂S maintained photosynthetic efficiency via improved stomatal openings and chloroplast structure, thus sustaining chlorophyll levels and stabilizing photosystem-II functionality. Enhanced proline accumulation following NaHS application led to improved osmotic adjustment, thereby contributing to overall stress tolerance. The use of a H₂S scavenger at 100 µM HT (Hypotaurine) suppressed the mitigating effects of H₂S, confirming the role of H₂S in enhancing drought tolerance in the common bean. Collectively, these findings highlight the potential effect of H₂S as a regulatory signaling molecule to enhance drought resilience in the common bean under drought stress conditions. Further research should explore integrating H₂S-based treatments with breeding programs and agronomic practices to develop sustainable strategies to improve drought resilience in legumes and other staple crops under changing climatic conditions. Full article

The use of nanoparticles (NPs) synthesized from plant extracts is an alternative to conventional pesticides for the control of agricultural pests. This study aimed to optimize the conditions of synthesis of silver–zinc nanoparticles (Ag-ZnNPs) using extracts of Ocimum basilicum L. and Crotalaria longirostrata Hook. & Arn. and to evaluate their phytotoxic impact on maize seedlings. The Ag-ZnNPs (Ag-Zn nanoparticles) were synthesized by redox reaction between metal ions and reducing metabolites present in the extracts. A response surface methodology (RSM) with three factors (extract concentration, heating time and pressure) was applied to determine the optimal synthesis conditions. The phytotoxicity of nanoparticles (NPs) on maize seedlings was subsequently evaluated on root growth, oxidative stress enzymes (CAT, POD, and APX), and physiology of seedlings. Nanoparticles synthesized from C. longirostrata extract demonstrated superior properties, with an optimization of synthesis (R² = 95.3%) where the extract concentration (1:4 v/v; p < 0.01) was the critical factor influencing the reduction of metallic ions to nanoparticles. These NPs exhibited superior stability, smaller size (<100 nm), and zeta potential greater than 30 mV compared with O. basilicum extracts. Their NPs exhibited poorer optimization of synthesis (R² = 43.8%) without the effect of any of the variables evaluated. Essentially, C. longirostrata NPs showed no phytotoxic effects on maize seedlings’ physiological parameters and enhanced root growth (117.2 mm) without negatively affecting photosynthesis (PSII 70-81 FvFm). Ag-ZnNPs synthesized with C. longirostrata exhibited optimal stability and size, along with no observed possible phytotoxicity effects, unlike O. basilicum NPs, which cause stress on maize seedlings. Therefore, Crotalaria longirostrata NPs could represent a promising material for agricultural pest control, with no apparent adverse effect on maize crops. Full article

Saline-alkaline (SA) soils pose a serious threat to soybean production worldwide. Although severe saline-alkaline stress can reduce yield by up to 30%, the mechanisms underlying saline-alkaline-induced inhibition of root growth remain unclear. In this study, two soybean cultivars with contrasting tolerance, Chang Nong 26 (CN26) and Jiyu 441 (JY441), were exposed to saline-alkaline stress induced by NaHCO₃ and Na₂CO₃ at Na⁺ concentrations of 0, 21, and 45 mmol·L⁻¹. The effects on seed germination, early seedling growth, antioxidant responses, and root DNA damage were systematically examined. High-level saline-alkaline stress significantly inhibited germination and root elongation in both cultivars. Superoxide dismutase (SOD) and peroxidase (POD) activities increased markedly under stress, indicating activation of antioxidant defenses. Catalase (CAT) and ascorbate peroxidase (APX) to scavenge ROS and maintain cellular redox balance. Nevertheless, oxygen-free radicals (OFRs) accumulated to a significantly greater extent in the root tips of CN 26 than in JY441, suggesting lower tolerance in CN 26. Random amplified polymorphic DNA (RAPD) analysis revealed pronounced DNA damage in root tips under saline-alkaline stress, with more polymorphic bands detected in CN 26 than in JY441. Furthermore, qRT-PCR analysis demonstrated that the expression of DNA damage repair-related genes (RAD51, OGG1, RAD4, and ATM) was downregulated in CN 26 roots under stress, whereas E2FA and WEE1 expression was upregulated. In contrast, these DNA repair genes in JY441 were significantly induced during the early stage of stress exposure and subsequently declined. Collectively, this study demonstrates that saline-alkaline stress inhibits soybean growth through the induction of oxidative DNA damage and cell cycle arrest in roots. The reduced capacity for DNA repair in CN 26 likely contributes to its greater sensitivity to saline-alkaline stress. This study provides mechanistic insights into saline-alkaline stress-induced growth inhibition in soybean and offers a theoretical basis for breeding stress-tolerant cultivars. Full article

Tobacco (Nicotiana tabacum L.) is an economically important crop in China. The risk of cadmium (Cd) pollution is increasing, making the mitigation of Cd stress critical for the safe production of tobacco. Silicon (Si) has been demonstrated to enhance plant growth under heavy metal stress. To elucidate the physiological and biochemical mechanisms by which Si alleviates Cd stress in tobacco, this study conducted a hydroponic experiment with three replicates using tobacco variety Yunyan 87 and employed one-way analysis of variance (ANOVA) for statistical analysis. The effects of Si on tobacco growth and the antioxidant defense system under Cd stress were investigated. The results showed that Cd stress significantly inhibited tobacco growth, increased Cd accumulation, and induced oxidative damage. Si treatment alleviated Cd stress in tobacco, increased biomass, reduced Cd concentration in different plant organs, and decreased the Cd translocation factor and bioconcentration factor. Meanwhile, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in tobacco roots and leaves were significantly enhanced, while the activities of ascorbate peroxidase (APX) and glutathione reductase (GR) were also elevated. The accumulation of ascorbic acid (AsA) and glutathione (GSH) increased, and malondialdehyde (MDA) concentration decreased. Overall, these results demonstrate that Si mitigates Cd stress in tobacco by limiting Cd accumulation and transport and by coordinately activating both enzymatic and non-enzymatic antioxidant systems. Full article

Idesia polycarpa Maxim. is an important woody oilseed species and is dioecious; however, systematic evidence for sex-specific differences in leaf physico-chemical traits and their spectral responses remains limited. In this study, mature female and male trees were investigated. Leaves were sampled throughout the growing season (May–October), and FTIR-ATR spectra were acquired to derive peak height and peak area metrics for diagnostic bands. In parallel, leaf antioxidant enzyme activities (SOD, CAT, POD, and APX), biomass-related traits, leaf nutrient concentrations, and rhizosphere soil nutrient indices were measured. Differences between sexes, seasonal dynamics, and spectrum–trait coupling were evaluated using repeated-measures analysis and correlation analyses. The results showed that the positions of major absorption bands were largely consistent between sexes, indicating broadly similar chemical composition, whereas the male plants lacked an obvious band near 1671 cm⁻¹ in May. Several spectral peak parameters were significantly correlated with leaf pH, leaf dry matter content, total phosphorus, and APX activity. Female and male plants exhibited month-dependent differences in enzyme activities, dry matter content, and leaf N and K, and leaf–soil nutrient linkages were also detected, suggesting sex-specific resource allocation patterns. Overall, FTIR-ATR peak metrics provide a rapid means to characterize seasonal variation in leaf physico-chemical properties of I. polycarpa and offer supporting evidence for studies of sexual dimorphism. Full article

It is estimated that at least 16.1% of croplands in China are polluted with heavy metals, and cadmium (Cd) is a typical toxic element inhibiting plant growth. Sorghum bicolor × S. sudanense, a C4 plant with high biomass and stress tolerance, has potential for phytoremediation, but its Cd tolerance mechanism remains unclear. In this study, physiological and transcriptomic responses of Cd-tolerant (S6) and sensitive (2190A/201900131) cultivars were analyzed under 25 mg/L Cd stress. The results showed that S6 exhibited milder phenotypic inhibition (leaf yellowing, growth retardation) than the sensitive cultivar. Cd was mainly accumulated in roots (S6: 4988.37 mg/kg; sensitive: 7030.06 mg/kg at 7 d), with S6 having a lower translocation factor. Physiologically, S6 maintained higher chlorophyll content, stable photosynthetic efficiency (Fv/Fm, PI), and lower malondialdehyde (MDA) accumulation, while antioxidant enzyme (SOD, CAT, APX) genes were significantly upregulated. Transcriptomic analysis identified 47,797 differentially expressed genes (DEGs), enriched in glutathione metabolism, ABC transporter-mediated transport, metal chelation, and antioxidant defense pathways. Genes related to cell wall biosynthesis, metal transporters (ZIP, HMA), and transcription factors (MYB, WRKY) were synergistically upregulated in S6, enhancing Cd sequestration and detoxification. These findings clarify the physiological and molecular mechanisms of Cd tolerance in Sorghum bicolor × S. sudanense, providing a basis for its application in Cd-contaminated soil phytoremediation. Full article

Salinity and drought are major constraints to wheat productivity, affecting growth, photosynthesis, and cellular homeostasis. While many studies have examined responses to these stresses individually, comparative evaluation of genotypes under both stresses using an integrated physiological, biochemical, and multivariate framework remains limited. Here, six wheat genotypes were evaluated at the seedling stage under controlled salinity and drought treatments to identify key morphological and physio-biochemical markers associated with stress resilience. Both stresses reduced shoot and root growth, biomass, gas exchange, and photosynthetic pigments, with drought causing stronger inhibition. Among genotypes, Akbar-2019 exhibited the greatest tolerance, maintaining higher growth, pigment stability, photosynthetic performance, and membrane integrity, whereas Subhani-2021 was the most sensitive. Stress-induced osmotic adjustment was evident from increased proline, soluble sugars, and free amino acids, particularly in Akbar-2019. Antioxidant enzymes (SOD, POD, CAT, APX) were elevated under both stresses; Akbar-2019 combined stronger antioxidant activity with lower malondialdehyde and hydrogen peroxide levels, indicating effective mitigation of oxidative damage. Multivariate analyses (PCA, heatmap clustering, and MGIDI) consistently ranked Akbar-2019 as the most resilient genotype. These findings provide a novel, integrative framework for screening wheat under multiple abiotic stresses, identify promising genotypes for breeding and cultivation in stress-prone environments, and highlight combined morpho-physiological stability, osmolyte accumulation, and antioxidant capacity as informative markers for stress tolerance. Full article

Ascorbate peroxidase (APX) plays a crucial role in both the removal of hydrogen peroxide and chloroplast development in response to light. To clarify the function of the APX gene family in oat (Avena sativa L.), we identified the family members and systematically analyzed their characteristics, phylogenetic relationships, promoter cis-elements, and expression patterns. Overall, 27 oat APX (AsAPX) members were identified in oat, and all encoded products had a peroxidase or peroxidase-like heptapeptide structure and motif. The genes were distributed unevenly across 15 chromosomes, with amino acid sequences ranging from 112 to 510 and molecular weights varying between 11.83 and 55.45 kDa. A phylogenetic analysis revealed that AsAPXs can be categorized into five branches, while an intra-group syntenic analysis identified 17 pairs of duplicate segments. Furthermore, 41 cis-element recognition sites were identified in the promoter regions of AsAPX genes, primarily comprising light-responsive and phytohormone-responsive elements. Moreover, qRT-PCR results indicated that AsAPX genes respond to light. Based on these results, our research establishes a foundation for exploration of AsAPX gene functionality and offers light-inducible candidate genes for chloroplast development to enhance A. sativa and improve crop production. Full article

Abiotic stresses disrupt redox homeostasis and reduce crop productivity. Antioxidant networks support resilience by limiting excess reactive oxygen species (ROS) and maintaining redox signalling for stress perception, gene expression, and metabolic reprogramming. We summarize advances (2000–2025) in ROS generation, detoxification mechanisms, and signalling across organelles, including chloroplasts, mitochondria, peroxisomes, and the apoplast. This includes compartmentalized enzymes—superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), and glutathione reductase (GR)—as well as the peroxiredoxin–thioredoxin system and non-enzymatic buffers like ascorbate, glutathione, tocopherols, carotenoids, and flavonoids. We uniquely synthesize these findings in a compartment-resolved “redox rheostat” model, linking ROS concentration–time windows (signaling vs. damage) to antioxidant network design (kinetic tiers, compartmentation, and trade-offs) and identifying intervention points for breeding, genome editing, and field-scale priming. We emphasize constraints, such as NADPH supply and antioxidant recycling capacity, that lead to context-dependent outcomes. We evaluate omics, transgenic strategies, genome editing (CRISPR and Cas systems), exogenous applications, and plant–microbe associations. This synthesis clarifies how antioxidant systems protect photosynthetic and respiratory machinery while supporting signalling, thus outlining routes to climate-resilient, yield-stable crops across varied environments and stresses. Full article

Mature-green tomatoes are prone to rapid ripening and quality deterioration during the postharvest stage, highlighting the urgent need for environmentally friendly and efficient preservation technologies. This study investigated the synergistic regulatory effects of nano-SiO₂ and light quality (white light, W; blue light, B; red/blue mixed light, RB, 1:1) on postharvest appearance, physiological processes, and quality attributes in ‘Yu Zhu’ (Solanum lycopersicum L.), a tasty tomato cultivar with light-yellow fruit color. Mature-green fruits were treated with light quality in combination with nano-SiO₂ (pre-immersion in 1 mL/L nano-SiO₂ for 1 h, followed by periodic spraying with 0.5 mL/L nano-SiO₂ every two days). Key indicators—including ripening traits, flavor attributes, antioxidant capacity, and endogenous hormone metabolites—were monitored on their respective sampling days. The results revealed distinct light quality-dependent responses: (1) B-Si (B + nano-SiO₂) significantly delayed the breaker stage compared to W, maintained the lowest water loss, and exhibited the slowest softening rate. W-Si showed a significantly higher dry weight-to-fresh weight ratio than W. (2) RB-Si achieved superior flavor quality, with 11.47% soluble solids, 1.62% titratable acidity, and a sugar-to-acid ratio of 7.2—values markedly higher than those in RB. (3) RB-Si increased total phenolic (TP), flavonoids, and ascorbic acid (AsA) levels relative to RB, while enhancing total antioxidant capacity (T-AOC) and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), with only slight suppression of ascorbate peroxidase (APX) activity. (4) Nano-SiO₂ differentially regulated hormonal metabolism depending on light quality: it activated the jasmonic acid (JA)–gibberellin (GA) pathway under W light, fine-tuned cytokinin (CK) metabolism under B light, and upregulated JA, GA, CK, and auxin under RB light. Moreover, RB-Si significantly reduced ACC accumulation compared to W, thereby delaying senescence. Collectively, RB-Si synergistically regulates endogenous hormone metabolism to simultaneously delay ripening, reduce water loss, maintain firmness, optimize flavor, and enhance antioxidant capacity. This study elucidates the interaction mechanism between nano-SiO₂ and light quality, providing theoretical and technical support for the green preservation of horticultural crops. Full article

Drought stress poses a serious threat to global agriculture, affecting plant growth, physiology, and biochemical processes, thereby impacting food security. Supplementation of phytohormones regulates plant physiological processes and improves tolerance to abiotic stress. In our study, we applied glycine betaine (GB), a non-toxic, highly soluble signaling molecule that plays an important role in protecting plants from environmental stress. To assess the role of with and without exogenous GB against fourteen days of prolonged drought stress (60% and 30% field capacity) on two high-yielding barley varieties, BARI barley-6 (sensitive) and BARI barley-9 (tolerant), with control plants were maintained at 90% field capacity. Results showed that both varieties exhibited a significant reduction in biomass, leaf relative water content, and photosynthetic activity under drought stress, while increasing the accumulation of proline and ROS, which indicates oxidative damage. In contrast, foliar application of GB improved growth, photosynthetic pigments, and net photosynthetic rate. It also helped to detoxify ROS by boosting the activities of antioxidant enzymes such as CAT, APX, POD, and GST while upregulating secondary metabolites like phenolic and flavonoid contents, maintaining membrane integrity, and regulating osmotic balance under water-deficient conditions. Overall, GB enhanced the drought tolerance of both barley varieties by modulating various physiological and biochemical processes. Our findings provide insights into GB-induced adaptation mechanisms in plants that combat water scarcity and may help to develop drought-resilient crops. Full article

Growing concern over soil degradation and the demand for sustainable solutions have driven research into remediation technologies. This study aimed to evaluate the morphological, physiological, and phytochemical responses of Larrea cuneifolia, Bulnesia retama, Plectrocarpa tetracantha, and Neltuma flexuosa seedlings exposed to mining waste contaminated soil during early developmental stages. Plants were cultivated for 90 days in soils amended with increasing concentrations of mining waste. Higher waste proportions resulted in a dose-dependent increase in metal(loid)s concentrations and soil acidification. All species survived in soils containing up to 1572.6 mg kg⁻¹ As, 25.6 mg kg⁻¹ Cu, 33.0 mg kg⁻¹ Cd, and 742.6 mg kg⁻¹ Zn. Metal(loid)s accumulation occurred predominantly in roots, reaching 1895.1 mg kg⁻¹ Zn in P. tetracantha and 2223.2 mg kg⁻¹ As in B. retama. The presence of metal(loid)s in leaf and stem tissues was confirmed by SEM-EDX analysis. Elevated MDA levels, combined with low POX and APX activities, indicated a limited antioxidant response. Additionally, the abundance of yeast and bacterial colonies increased across all soil treatments associated with the studied native species. These results demonstrate remarkable tolerance of native species to multi-metal contamination and underscore their potential for cost-effective, nature-based strategies to restore mining-impacted soils in arid regions. Full article

In the context of global climate change, the co-occurrence of salt and heat stress represents a major constraint to rice production, resulting in greater yield penalties than either stress alone. This study aimed to assess the effects of salt and heat stress on oxidative homeostasis, photosynthetic performance, carbon (C)–nitrogen (N) metabolism, and rice yield. The experiment comprised four treatments, i.e., control (CK), salt (irrigation with 3.9 dS m⁻¹ NaCl solution), heat (exposure to 36 °C/30 °C day/night for 5 days at panicle initiation), and combined salt + heat stress. Results showed that combined stress enhanced reactive oxygen species (ROS) accumulation (i.e., H₂O₂ content and O₂⁻ contents were 1.3 and 1.5 times higher than CK), and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were increased by 64.6%, 69.5%, and 74.8% higher than CK. At the molecular level, salt + heat stress upregulated antioxidant defense-related genes, i.e., OsAPX2, OsSODCC1, and OsAPX1, while significantly downregulated ion homeostasis-related genes, i.e., OsSOSs, OsHKT1;3, OsHKT1;5, and OsNHX4, and photosynthesis-related genes, i.e., Ospsbo, OsRbcS2, and OsRbcS3, compared with CK. Furthermore, salt + heat stress reduced the activities of C-metabolism enzymes (sucrose phosphate synthase, sucrose synthase, and starch synthase) and N-metabolism enzymes (nitrate reductase, glutamine synthetase, and glutamate synthase), leading to 34.3% and 18.6% lower stem-sheath non-structural carbohydrate accumulation in stem sheath and its translocation rate, respectively, while total N accumulation decreased by 42.9%, as compared with CK. Ultimately, these cascading effects inhibited panicle development and reduced yield. The findings provide a theoretical basis for improving rice tolerance to combined abiotic stresses by targeting oxidative stress mitigation, photosynthetic protection, and key stress-responsive gene regulation. Full article

Ascorbate peroxidase (APX) is a heme-containing enzyme involved in hydrogen peroxide (H₂O₂) detoxification within the ascorbate–glutathione (AsA–GSH) cycle. In this study, the full-length genomic DNA and cDNA of an APX1 gene (VsAPX1) were cloned and characterized from Vicia sativa. The genomic sequence of VsAPX1 is 2425 bp in length and comprises 10 exons separated by nine introns, with the first intron located within the 5′ untranslated region (5′UTR). The corresponding cDNA is 1010 bp long and includes a 61 bp 5′UTR, a 753 bp open reading frame, and a 196 bp 3′UTR. VsAPX1 encodes a predicted cytosolic APX protein of 250 amino acids, with a molecular weight of 27.1 kDa and a theoretical isoelectric point (pI) of 5.60. Bioinformatics analysis revealed that the deduced VsAPX1 protein shares high sequence similarity with cytosolic APX1 proteins from other plant species, contains conserved APX domains, and clusters within the cytosolic APX clade in phylogenetic analysis. Quantitative real-time PCR analysis showed that VsAPX1 expression exhibits transient and moderate changes in response to abiotic stress and phytohormone treatments. Transcript levels increased at early time points following heat stress (42 °C), abscisic acid, and salicylic acid treatments, and after 4 h of jasmonic acid exposure, whereas hydrogen peroxide treatment resulted in a gradual down-regulation of expression. Overall, this study provides the first molecular and expression characterization of a cytosolic APX1 gene from Vicia sativa and establishes a foundation for future functional analyses of antioxidant genes in this species. Full article