Search Results (917)

Thai eggplant (Solanum melongena L. cv. Chao Phraya), a widely cultivated vegetable with increasing global demand, is highly susceptible to salinity stress, which can severely impair seed germination and early seedling development. This study investigated the effects of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on seed germination and seedling growth under salt stress conditions. Seeds were pre-treated with SNP at concentrations of 0, 0.05, 0.1, and 0.2 mM for 24 h and subsequently germinated under saline conditions with NaCl solutions (0, 100, and 200 mM). SNP pre-treatment, particularly at 0.05 and 0.1 mM, significantly improved germination percentage and germination rate in seeds exposed to 200 mM NaCl compared to untreated controls. Increased NaCl concentrations induced oxidative stress in seedlings, as evidenced by elevated hydrogen peroxide (H₂O₂) accumulation, which in turn caused lipid peroxidation, reflected by higher malondialdehyde (MDA) levels. Salt stress significantly increased ascorbate peroxidase (APX) activity, whereas catalase (CAT) activity showed no significant change across treatments. Correlation analysis revealed that APX activity was positively correlated with oxidative stress markers (H₂O₂) and delayed germination (T₅₀/MGT), whereas CAT activity showed no significant correlation with these parameters. In contrast, elevated APX activity was strongly and negatively correlated with overall seedling growth and vigor (SVI/GI), indicating that the underlying stress condition had a detrimental effect on plant performance. Overall, SNP pre-treatment, particularly at 0.05 and 0.1 mM, significantly enhanced salt tolerance by promoting germination (increasing GP and reducing T₅₀/MGT) and improving seedling growth (SL and RL). This protective effect is associated with improved redox regulation and partial mitigation of oxidative damage, as reflected by changes in H₂O₂, MDA, and APX; however, excessive SNP concentrations may exert phytotoxic effects, highlighting the importance of optimal dosing. Full article

This study aimed to evaluate the effect of stress attenuators on the tolerance and antioxidant activity of watermelon cultivars under water deficit. The experiment was conducted in two stages, Stage I corresponding to water deficit levels (N1 = 0; N2 = −0.1; N3 = −0.2 MPa) and six watermelon cultivars. Stage II comprises two cultivars selected in Stage I (one sensitive and one tolerant) and the combination of water restriction with attenuators (T1 = 0.0 MPa (control), T2 = −0.2 MPa (water deficit), T3 = −0.2 MPa + hydropriming, T4 = −0.2 MPa + gibberellic acid, T5 = −0.2 MPa + salicylic acid, and T6 = −0.2 MPa + hydrogen peroxide). The concentration and exposure times of the attenuators were determined through preliminary tests. In Stage I, physiological and biochemical analyses were performed. In Stage II, in addition to these tests, hydrogen peroxide content, malondialdehyde levels, and the activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) were assessed. Water deficit impaired germination and seedling vigor of watermelon, with Crimson Sweet, Omaru, Charleston Gray, and Congo being the most sensitive cultivars, while Fairfax was the most tolerant. For Crimson Sweet, pre-germination treatments reduced oxidative stress and enhanced tolerance by stimulating antioxidant enzyme activity, with GA and H₂O₂ providing the most effective results. For Fairfax, greater tolerance was associated with osmotic adjustment through the accumulation of compatible solutes, a mechanism further enhanced by the use of attenuators. Full article

Betaphycus gelatinus, a member of the Eucheumatoideae, serves as the primary source for carrageenan extraction and has significant economic value. The growth and reproduction of B. gelatinus are significantly impacted by seasonal fluctuations in seawater temperature. To explore its adaptive mechanisms under temperature stress, we cultured the algae at 15 °C (Low temperature, LT), 27 °C (Medium temperature, MT), and 36 °C (High temperature, HT) for 2 h and conducted subsequent physiological, transcriptomics, and metabolomics analyses. The photosynthetic performance of B. gelatinus significantly declined under both LT and HT stress conditions. Carotenoid content increased significantly under LT conditions, while chlorophyll a showed no significant change. Phycocyanin and phycoerythrin decreased significantly under LT conditions, but there was no significant difference under HT conditions. Under LT stress, glutathione (GSH) levels, ascorbate peroxidase (APX) activity, and catalase (CAT) activity all increased significantly. Under HT stress, APX and CAT activities increased significantly, while superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels remained unchanged. Transcriptomics and metabolomics analyses suggested that photosynthesis, carbohydrate metabolism, amino acid biosynthesis, porphyrin metabolism, and vitamin B6 metabolism are involved in the acute temperature stress response of B. gelatinus. Under both HT and LT, most genes in the targeted metabolic pathways were significantly downregulated (p < 0.05), while only a few were upregulated. Specifically, in carbohydrate metabolism, only nine genes were upregulated, while all others were downregulated. Moreover, all the genes involved in photosynthesis, photosynthetic carbon fixation, arginine biosynthesis, and porphyrin metabolism were downregulated. In contrast, only four genes involved in GSH metabolism, alanine, aspartate, and glutamate metabolism, and glycine, serine, and threonine metabolism were upregulated. These results suggest that temperature stress markedly suppresses the transcription of key genes in these pathways and that the few upregulated genes in these pathways may contribute to compensatory mechanisms or regulatory network reprogramming during stress responses. These findings help clarify how B. gelatinus adapts to different temperature stresses and provide a basis for developing improved germplasm to support stable production under climate variability. Full article

While cold storage is essential to extend the postharvest preservation of litchi fruit, the abrupt transfer to ambient temperature during supply chain transitions may trigger rapid quality degradation. However, the comprehensive mechanisms and critical threshold of post-transfer quality deterioration remain insufficiently characterized. In this study, litchi fruits were stored at 4 °C for 10, 20, and 30 days, followed by simulated shelf life at 25 °C. Key indicators, including appearance quality, antioxidant capacity, lipid peroxidation, and enzymatic oxidation, were monitored, and principal component analysis (PCA) was used to determine quality deterioration thresholds. Litchi subjected to 30 d of cold storage exhibited significantly accelerated pericarp browning compared to those stored for 20 d and 10 d, with the browning index increasing by 25.7% (vs. 20 d) and 41.9% (vs. 10 d), respectively, after 24 h of ambient exposure. This was accompanied by a significant impairment of the antioxidant system. Compared to the fruits stored for 10 d and 20 d, the activities of key antioxidant enzymes (SOD, CAT, and APX) were substantially decreased in the 30 d group, with reductions ranging from approximately 9% to 28%. Concurrently, the non-enzymatic antioxidant capacity also declined. Meanwhile, 30 d of storage activated the browning-related enzymes: anthocyanase and peroxidase (POD) activities increased by 1.2- to 3.6-fold, and poly-phenol oxidase (PPO) activity increased by 11% to 37%, compared to the 10 d and 20 d groups, respectively. In contrast, phenylalanine ammonia lyase (PAL) activity was inhibited by 56.9%. It also enhanced membrane lipid metabolism disorders, which aggravated cell structure damage and oxidative stress. For practical application, PCA identified 10 d (4 °C) + 6 h (25 °C), and 20 d (4 °C) + 12 h (25 °C) as the optimal and critical quality thresholds, respectively. This study reveals the interactive regulatory relationship between cold storage duration and ambient exposure time mediated by oxidative stress, enzymatic browning, and membrane lipid metabolism, providing a theoretical basis for developing time-temperature-quality models to reduce postharvest losses in litchi. Full article

Chilling injury (CI) is a major constraint to the postharvest shelf-life of tomato fruit (Solanum lycopersicum L.), leading to severe quality deterioration, which is closely linked to cell membrane damage. While individual postharvest treatments with the elicitors, such as methyl salicylate (MeSA), methyl jasmonate (MeJA), and the nitric oxide donor sodium nitroprusside (SNP), alleviate cold stress, their synergistic potential in combination has not been systematically explored. The present study evaluated the postharvest efficacy of 1 mM MeSA, MeJA, SNP, and their combinations (MeSA + MeJA, MeSA + SNP, MeJA + SNP) on ‘Vivalto RZ’ tomato fruits stored for 20 days at 2 °C, followed by a 2-day shelf-life period at 20 °C. All treatments effectively mitigated quality loss and CI incidence compared to the control. Notably, the MeSA + SNP and MeJA + SNP combinations demonstrated the highest efficacy, resulting in the lowest CI indices (1.2–1.4 vs. 3.4 in control) and the best preservation of firmness and titratable acidity. This enhanced tolerance was correlated with improved membrane integrity (lower malondialdehyde content and ion leakage) and the strongest upregulation of the antioxidant system, specifically achieving the highest ascorbate peroxidase (APX) activity. The combined application of MeSA or MeJA with SNP exerts a synergistic effect that provides superior chilling tolerance, representing a highly effective and commercially viable strategy to extend the postharvest shelf-life of tomato fruit. Full article

As a coastal brush, Atalantia buxifolia is a good rootstock of citrus plants around sea shores, but its salt tolerance has not been studied. In order to explore the salt tolerance of A. buxifolia, its seeds and seedlings were subjected to NaCl stress treatment, followed by phenotypic observation and biochemical and transcriptome analysis. Results showed that the increase in NaCl concentrations resulted in the decrease in germination rates, germination potential, germination index, and vigor index of A. buxifolia seeds, as well as growth of epicotyl and radicle, and biomass of A. buxifolia seedlings. However, the seeds of A. buxifolia could adapt to the growth of 100 mM NaCl concentration to a certain extent. The levels of malondialdehyde (MDA) and relative electrolyte leakage increased with the increase in NaCl concentrations. However, under treatment of 100 mM NaCl, the biomass, POD, CAT, APX, GSH, AsA, H₂O₂, MDA, and relative electrolyte leakage of A. buxifolia seedlings did not show significant changes compared with the control treatment. Transcriptome analysis showed that expression of differential genes increased with the increase in NaCl concentrations. GO enrichment showed that the most annotated genes were metabolic process, cell and cell composition, and binding. The KEGG pathway annotation shows that differential genes were mainly enriched in some pathways, such as photosynthesis antenna proteins, plant hormone signal transduction, glutathione metabolism, and starch and sucrose metabolism. In addition, differentially expressed genes had been annotated into 45 transcription factor families, including the largest number of bHLH, NAC, WRKY, MYB, and bZIP families. The results provide a basis for further understanding the salt tolerance mechanism and exploring related salt tolerance genes of A. buxifolia. Full article

Spring frost poses a major threat to grape-producing regions, severely reducing grape yield and quality. Grafting rootstocks is an effective strategy for enhancing scion resistance to spring frost and mitigating damage. In this study, the two wine grape cultivars (‘Cabernet Sauvignon’ and ‘Chardonnay’) grafted onto three rootstocks (‘Beta’, ‘Kober 5BB’, and ‘3309 Couderc’) were evaluated for their spring frost resistance on one-year-old vines. The scion–rootstock combinations exhibited significantly less photosynthetic impairment under frost stress compared with own-rooted vines. Rootstock also showed lower levels of proline accumulation in the roots and APX activities in the leaves under frost conditions. Compared with own-rooted vines, VvCBF1 gene expression were significantly upregulated in the grafted combinations under frost stress conditions. Among the tested rootstocks, ‘Kober 5BB’ markedly improved the spring frost resistance of both cultivars. CH/5BB exhibited the highest activities of POD and APX activity and the greatest induction of VvCBF genes, along with the lowest relative electrical conductivity and H₂O₂ content. These results highlight the critical role of rootstocks in improving scion spring frost resistance and provide important guidance for selecting suitable rootstocks to mitigate the impact of late frosts. Full article

Edible Grass (EG) is a hybrid vegetable variety valued for its high biomass and protein content, garnering significant interest in recent years for its potential in food, feed, and health product applications. However, in subtropical climates, intense light and high temperatures severely affect the growth and development of Edible Grass (EG), leading to substantial reductions in yield and quality. This study was conducted in the subtropical humid monsoon climate zone of Changsha, Hunan, China, comparing two growth conditions: natural light (CK) and shading treatment (ST). High light-aggravated heat damage under CK significantly reduced EG yield and quality (p < 0.05), with severe cases leading to plant death. and could even lead to plant death in severe cases. Specifically, maximum air and leaf temperatures under CK reached 38.85 °C and 38.14 °C, respectively, well exceeding the plant’s optimal growth range. Shading treatment (ST) effectively alleviated this damage, significantly increasing the net photosynthetic rate, stomatal conductance, and intercellular CO₂ concentration, while decreasing leaf temperature and transpiration rate (p < 0.001). The analysis of physiological and biochemical indicators indicates that after ST, the activities of SOD, CAT, and POD in the leaves decreased, while the contents of MDA and H₂O₂ were significantly lower compared to the CK group (p < 0.001). The transcriptome sequencing results indicate that a total of 8004 DEGs were identified under shading treatment (ST) relative to natural light (CK), with 3197 genes upregulated and 4807 genes downregulated. Significantly enriched Gene Ontology (GO) terms include ‘cell membrane’, ‘extracellular region’, and ‘protein kinase activity’, while significantly enriched KEGG metabolic pathways include ‘plant hormone signal transduction’, ‘photosynthesis–antenna proteins’, and ‘glutathione metabolism’. Compared to CK, the expression of genes associated with oxidative stress (e.g., CAT1, OXR1, APX, GPX) was significantly downregulated in ST, indicating a relief from light-aggravated heat stress. This transcriptional reprogramming was corroborated by metabolomic data, which showed reduced accumulation of key flavonoid compounds, aligning with the downregulation of their biosynthetic genes as well as genes encoding heat shock proteins (e.g., Hsp40, Hsp70, Hsp90). It indicated that plants switch from a ‘ROS stress–high energy defense’ mode to a ‘low oxidative pressure–resource-saving’ mode. Collectively, ST significantly alleviated the physiological damage of forage grasses under heat stress by modulating the processing of endoplasmic reticulum heat stress proteins, plant hormones, and related genes and metabolic pathways, thereby improving photosynthetic efficiency and yield. The findings provide a theoretical basis for optimizing the cultivation management of EG, particularly in subtropical regions, where shade treatment serves as an effective agronomic strategy to significantly enhance the stress resistance and yield of EG. Full article

Drought is a major problem affecting upland rice growth worldwide, including in northeast Thailand, with insufficient irrigation, where drought stress leads to reduced yields and may affect the functional compound content of rice grains. This research aimed to study the efficacy of arbuscular mycorrhizal fungi (AMF) Rhizophagus variabilis KS-02 and endophytic fungi (EPF) Trichoderma zelobreve PBMP16 on promoting the growth and accumulation of functional substances in upland black rice under drought conditions. Factorial experiments in a randomized complete block design (RCBD) were conducted by cultivating rice inoculated with AMF and EPF as well as co-inoculated with AMF+EPF under three watering conditions: 100% field capacity (FC), 66% FC, and 33% FC. The results show that both AMF, EPF improved some plant growth parameters and physiological performance under both well-watered and water-limited conditions. Inoculating plants with fungi increased the production of enzymes APX, CAT, and GR, as well as proline, which helps plants tolerate water deficit stress. Functional grain quality, including phenolic compounds, anthocyanins, and antioxidant activity, was also increased by fungal inoculation. While co-inoculation provided advantages for certain parameters, particularly antioxidant activity and biomass, single inoculation with AMF or EPF was equally effective or superior for specific traits depending on the level of water stress. Overall, this report shows that both AMF and EPF contribute to improving the productivity and functional quality of upland black rice under drought conditions, with treatment effects varying according to fungal type and water availability. Full article

Zearalenone (ZEN) poses serious risks to human and animal health. Compared with physical and chemical methods, microbial transformation offers a safer and more sustainable strategy for ZEN detoxification. The yeast Hannaella zeae, isolated from the Qinghai–Tibet Plateau, showed the highest ZEN removal efficiency among 11 strains, achieving an 85.87% transformation rate within 36 h. Optimal conditions for ZEN transformation were determined by varying culture time, temperature, and pH. The products were putatively identified as zearalenone-14-β-D-glucopyranoside (C₂₄H₃₂O₁₀) and zearalenone-16-β-D-glucopyranoside (C₂₄H₃₂O₁₀) by UHPLC-Q-Orbitrap-HRMS. The safety of the mixed culture medium extract was further evaluated using a Caenorhabditis elegans model, showing significantly lower toxicity than untreated ZEN. H. zeae maintained high transformation efficiency under low temperature (57.48%) and acidic stress (47.10%), supported by active antioxidant enzymes (SOD, CAT, APX, GPx) and stress metabolites (trehalose, proline). Overall, this study identifies H. zeae as a promising, stress-tolerant biocontrol agent and elucidates its glycosylation-based detoxification mechanism, providing a foundation for future application in real food and feed systems. Full article

Seed germination of celery (Apium graveolens L.) is notoriously slow and asynchronous, which severely constrains uniform seedling establishment and crop yield. Seed priming is an effective technique to improve germination, and acidic electrolyzed water, characterized by low pH and high oxidation–reduction potential, has emerged as a novel priming agent. However, the effect of acid electrolyzed water priming (EWP) on celery seed germination and the underlying mechanisms still need to be explored. The present study aimed to investigate the physiological and molecular mechanisms by which EWP promotes celery seed germination, with a focus on the roles of the phenylpropane metabolism and the antioxidant enzyme system. Celery seeds were treated with EWP, hydro-priming (HYD), and untreated (CK). It was found that the EWP treatment significantly enhanced germination characteristics compared to both CK and HYD. Transcriptome analysis revealed that EWP triggered more extensive transcriptional reprogramming than HYD, and EWP specifically enriched “Phenylpropanoid biosynthesis” and “Flavonoid biosynthesis” pathways, downregulating upstream genes (PAL, 4CL) while upregulating downstream genes (CCR, CHI, F3H) in the phenylpropane pathway. Physiologically, EWP significantly increased CHI activity and the contents of total phenols and flavonoids at all sampling time points, and enhanced the activities of SOD, POD, CAT, and APX. Consequently, the DPPH and FRAP free radical scavenging capacities were significantly strengthened in EWP-treated seeds. In conclusion, it is believed that EWP activation promotes celery seed germination by coordinating the phenylpropane pathway and antioxidant enzyme system, ensuring effective radical scavenging activities and cell protection. These findings provide a theoretical basis for the application of EWP and highlight the potential as a novel priming technology for celery and other horticultural crops. Full article

Induced resistance in plants is a promising strategy for pest management, helping to reduce dependence on synthetic pesticides. However, no study has yet examined the interaction between Tetranychus urticae and Aronia melanocarpa, including host acceptance, performance, and antioxidant defence mechanisms. In this study, host acceptance of T. urticae was evaluated using two A. melanocarpa ecotypes: a non-cultivar (AMe) and the cultivated variety ‘Galicjanka’ (AGe). Leaf morphological traits (trichome density and length) and key life-history parameters of the mite (fecundity, egg development time, and larval duration) were assessed. Mite feeding effects on oxidative stress markers (hydrogen peroxide—H₂O₂; thiobarbituric acid reactive substances—TBARS) and antioxidant enzyme activity (guaiacol peroxidase—GPX ascorbate peroxidase—APX) were analysed by ecotype and infestation duration. Results showed low fecundity and prolonged development, indicating that neither ecotype is a preferred host for T. urticae. Ecotype-dependent differences in acceptance and mite performance suggest that variation in trichome density and biochemical traits may influence susceptibility. Baseline differences in H₂O₂ and TBARS imply a role in constitutive resistance, while their induction, accompanied by increased GPX and APX activity, highlights oxidative stress and antioxidant defences as key components of A. melanocarpa responses to mite attack. Full article

Modern agriculture relies heavily on chemical inputs to sustain productivity, yet their intensive use poses environmental and health risks. Sustainable strategies based on biostimulants have emerged as promising alternatives to reduce agrochemical dependence. Among these compounds, humic substances (HS) stand out for their ability to modulate plant growth and activate defense responses. This study aimed to evaluate the effects of HS from different sources—vermicompost (Vc) and peat (Pt)—on the salicylic acid (SA)-mediated defense pathway in tomato plants (Solanum lycopersicum cv. Micro-Tom) infected with Oidium sp. The HS were characterized by solid-state ¹³C CPMAS NMR to determine the relative distribution of carbon functional groups and structural domains, including alkyl, O-alkyl, aromatic, and carbonyl carbon fractions, as well as hydrophobicity-related indices. Enzymatic activities of lipoxygenase, peroxidase, phenylalanine ammonia lyase, and beta 1,3-glucanase were determined spectrophotometrically, and RT-qPCR quantified gene transcription levels involved in SA signaling and defense (MED25, MED16, MED14, NPR1, ICS, PAL, LOX1.1, MYC2, JAZ, jar1, CAT, POX, SOD, APX, ERF, PR-1, PR-2, PR-4 e PR-5). Both HS significantly reduced disease severity and activated key SA-related defense genes, including the regulatory gene NPR1 and the effector genes PR1, PR2 and PR5, with Pt providing greater protection. Notably, HS amplified defense-related gene expression and enzymatic activities specifically under infection, showing a stronger induction than in non-infected plants. These results demonstrate that structural differences among HS drive distinct and enhanced defense responses under pathogen challenge, highlighting their potential as sustainable tools for improving plant immunity in agricultural systems. Full article

Drought significantly reduces global crop yields and agricultural productivity. This study aims to isolate drought-tolerant PGPR strains and evaluate their effects, both individually and in combination with salicylic acid (SA), on cowpea plants growth, physiological traits, antioxidant enzymes, and mineral content under both drought stress and non-stress conditions. Among fifteen bacterial isolates, AO7, identified as Streptomyces diastaticus subsp. ardesiacus PX459854 through 16S rRNA sequencing, demonstrated significant plant growth promotion in cowpea under gnotobiotic conditions. On the other hand, varying salicylic acid concentrations (0.5, 1.0, and 2.0 mM) was exposed to assess the plant growth of cowpea plants in a gnotobiotic system. A pot experiment in 2023 used a split-plot design with treatments for irrigation (unstressed and stressed) and different soaking treatments (control, S. diastaticus, salicylic acid (2 mM), and a combination). After 60 days, the combination treatment enhanced growth metrics, outpacing the control under stress. The microbial community in the T4 treatment exhibited the highest counts, while T8 (combination, stressed) showed lower counts but the highest chlorophyll content at 6.32 mg g⁻¹ FW. Notable increases in proline and significant changes in enzyme activities (PO, PPO, CAT, and APX) were observed, particularly in treatment T8 under stress, indicating a positive response to both treatments. Mineral content of cowpea leaves varied with soaking treatments of S. diastaticus and SA (2.0%) especially under drought stress which the highest values were 1.72% N, 0.16% P, and 2.66% K with treatment T8. Therefore, T8 (combination, stressed) > T6 (S. diastaticus, stressed) > T7 (salicylic acid, stressed) > T5 (control, stressed) for different applications under stressed conditions and T4 (combination, unstressed) > T2 (S. diastaticus, unstressed) > T3 (salicylic acid, unstressed) > T1 (control, unstressed) for the other applications under normal conditions. Thus, using S. diastaticus and SA (2.0%) in combination greatly enhanced the growth dynamics of cowpea plants under drought stress conditions. Full article

Solanum lycopersicum plants were grown in pots amended with biochar and PGPMs (plant growth-promoting microorganisms: Pseudomonas fluorescens and Azotobacter chroococcum), applied singularly and in combination, for three months, after which plants and soils were collected, divided into treatment groups based on organs, and analyzed. The following biochemical markers were studied: cellular respiration, shoot fresh and dry weight, root fresh weight, photosynthetic pigments (chlorophyll a, chlorophyll b, and carotenoids), membrane lipid peroxidation, proline content, total antioxidant capacity (DPPH and ABTS assay), hydrogen peroxide, ascorbic acid, total phenolic content, enzymatic activity (SOD, POD, CAT, and APX), total soluble sugar content, and total protein content. Also, soil parameters, such as pH, EC, total enzymatic activity, active carbon, and respiration, were measured. While biochar alone induced root H₂O₂ accumulation, its co-application with PGPMs turned this signal into a systemic trigger for defense, enhancing the antioxidant capacity and the production of proline, phenolics, and ascorbic acid without causing oxidative damage. At the soil level, microorganisms counteracted biochar’s inhibitory effects on enzymatic activity and intensified labile carbon use, indicating a more dynamic rhizosphere. Multivariate analysis confirmed that the combined treatment remodulated the plant–soil system, converting a stress factor into a resilience enhancer. This synergy underscores the role of biochar as an effective microbial carrier and PGPM consortia as bioactivators, together providing a powerful tool to prime crops against climate stress while preserving soil health. Full article