Search Results (5,906)

Light availability is a key environmental factor regulating nitrogen assimilation, carbon metabolism, and nutritional quality in leafy vegetables grown in controlled environments. However, how practical lighting regimes used in plant factories with artificial lighting (PFALs) influence the coordination between nitrogen assimilation and central carbon metabolism across different lettuce cultivar types remains insufficiently understood. This study investigated how moderate differences in photosynthetic photon flux density (PPFD) influence nitrogen metabolism and metabolic coordination in hydroponically cultivated lettuce. Two cultivars representing contrasting morphological types, iceberg lettuce (‘Celebration’) and leaf lettuce (‘Sunny’), were grown under LED light intensities of 150 and 200 µmol·m⁻²·s⁻¹. Nitrate, nitrite, and ammonium concentrations were measured together with the activities of nitrate reductase (NRA) and nitrite reductase (NiRA), as well as ascorbic acid content. Metabolomic profiling was additionally performed to characterize broader metabolic responses. Higher light intensity enhanced nitrate reduction capacity in both cultivars, but the resulting patterns of nitrogen accumulation were strongly genotype-dependent. The leaf lettuce cultivar ‘Sunny’ exhibited increased NRA and reduced nitrate accumulation under higher light intensity, whereas the iceberg lettuce cultivar ‘Celebration’ accumulated more nitrate under the same conditions. Ammonium responses further suggested differences in downstream nitrogen assimilation processes. Elevated light intensity also increased ascorbic acid levels in both cultivars. Metabolomic analysis revealed contrasting cultivar-specific shifts in central carbon metabolism, particularly involving soluble sugars and tricarboxylic acid cycle intermediates, indicating differential coordination between carbon metabolism and nitrogen utilization. Overall, these findings demonstrate that moderate changes in light intensity within the practical PFAL cultivation range can significantly influence the integration of carbon and nitrogen metabolism in lettuce. Importantly, cultivar-specific physiological traits determine how these metabolic responses translate into nitrate accumulation and nutritional quality in controlled-environment production systems. Full article

Tomato landraces possess distinct flavors, colors, textures and aromas, making them suitable for traditional cuisine. Tomato landraces contain a wide range of genes, including those involved in fruit quality, that can be isolated and used in local breeding programs. In regions recognized as centers of origin, domestication and diversification, traditional farmers play an important role in the preservation of tomato landraces adapted to local conditions and agricultural practices, on the whole maintaining high genetic diversity. This work aimed to evaluate the effects of the crop cycle (C), genotype (G) and C × G interactions on the contents of soluble solids, reducing sugars, lycopene, total polyphenols, flavonoids, and vitamin C, as well as the pH and antioxidant activity, in fifteen tomato landraces (genotypes) undergoing phenotypic selection and a commercial tomato variety (control). All the varieties were grown in two crop cycles under uniform greenhouse management using a randomized block design with four repetitions. Fruit composition was analyzed with AOAC and spectrophotometric methods. Significant differences (p ≤ 0.01) were detected in the soluble solid content, pH, flavor and maturity indices, polyphenol and flavonoid contents, and antioxidant activity between C, G and C × G interactions. In contrast, titratable acidity, reducing sugars, lycopene and vitamin C did not differ between cycles. Coefficients of phenotypic and genotypic variation and broad-sense heritability (H²) ranged from 4.3 to 33.7, 2.0 to 19.0, and 3.2 to 63.5%, respectively. H² for bioactive compounds ranged from moderate to slightly high (16.3–38.8%). These findings, supported by laboratory analyses, suggest that genotypes under agronomic selection have potential as parents to enhance fruit quality in current and future breeding programs. Full article

The protection of leaves from photoinhibition and berries from dehydration and sunburn has become an increasingly important objective in response to the rising frequency and intensity of heat waves worldwide. This research investigated the effect of a white nonwoven geotextile sheet (TNT) installed in the fruiting zone in the white cultivar ‘Verdicchio’ (Vitis vinifera L.) during critical summer periods with the aim of protecting leaves and berries from extreme heat. The study was conducted over two seasons (2020–2021) in a rainfed vineyard in central Italy using a randomized block design. Physiological and yield parameters were recorded. Vines protected with TNT did not show any changes in net photosynthesis, stomatal conductance, and water use efficiency, compared to unshielded vines. However, TNT reduced leaf temperature and increased berry total acidity and malic acid concentration while reducing sugar content, leading to wines with higher freshness and reduced alcohol levels. The use of TNTs shows significant potential as a practical tool for viticulturists to mitigate the effects of excessive heat, allowing for better management of berry ripening and ultimately improving final wine characteristics. Additionally, TNT is economically feasible, especially if applied only to the afternoon-exposed side of the canopy, and its cost can be amortized, especially in vineyards affected by frequent heat waves and/or dedicated to the production of premium wines. Full article

Seasonal drought constitutes a major abiotic stress limiting the growth and yield of pineapple, a globally important Crassulacean acid metabolism (CAM) crop. The sucrose catabolism mediated by cell wall invertase (CWIN) plays a vital role in regulating plant growth and development, as well as adaptive responses to abiotic stresses. Invertase inhibitors (INHs) serve as specific post-translational regulators that modulate CWIN enzymatic activity. However, the INH family has not been systematically characterized in pineapple, and its functional roles in mediating sucrose metabolism and drought resistance remain elusive. In this study, three AcINHs were identified from the pineapple genome, followed by comprehensive analyses of their gene structures, phylogenetic relationships, homology characteristics and protein structures. Structural analysis revealed that all AcINH members harbor conserved motifs 1, 2, 3, 5 and 9, whereas only AcINH3 possesses motif 7. Expression analysis showed that only AcINH3 was significantly transcriptionally induced by drought stress among all family members. Functional validation demonstrated that AcINH3 knockout markedly elevated CWIN activity in pineapple seedling leaves, facilitating hexose accumulation and promoting plant growth and development. Moreover, AcINH3-edited lines exhibited enhanced drought resistance, accompanied by increased accumulation of soluble sugars (sucrose, glucose, fructose), abscisic acid (ABA), and proline (PRO), reduced malondialdehyde (MDA) content, and enhanced peroxidase (POD) activity. Biochemical assays further verified a direct physical interaction between AcINH3 and AcCWIN1, which mediates sucrose metabolism and drought stress responses. Collectively, this study identifies a novel AcINH3–AcCWIN1 post-translational module that modulates sugar metabolism and drought tolerance in pineapple, providing critical mechanistic insights for CAM plants. Our findings highlight AcINH3 as a promising target for genome-editing breeding to enhance drought resistance in CAM crops. Full article

In arid and semi-arid regions, the cultivation of artificial grasslands commonly suffers from low productivity due to insufficient water supply. The rational application of water-retaining agents is an important approach to alleviating production constraints in artificial grasslands facing resource-based water scarcity. This study investigated two types of water-retaining agents [starch-grafted acrylate water-retaining agent (B1) and polyacrylamide water-retaining agent (B2)] and four application rates [0 kg·hm⁻² (CK), 30 kg·hm⁻² (T1), 60 kg·hm⁻² (T2), 90 kg·hm⁻² (T3)], systematically analyzing their effects on the growth, osmotic adjustment substances, antioxidant enzyme activities, and yield of alfalfa. The results showed that alfalfa plant height, stem diameter, leaf area, branch number, soluble sugar (SS), soluble protein (SP), and proline (Pro) all exhibited a decreasing trend with increasing cutting times. The activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in alfalfa leaves initially increased and then decreased with increasing application rates of water-retaining agents, while malondialdehyde (MDA) content showed a decreasing trend. Under the B2T2 treatment, both alfalfa yield and water-use efficiency (WUE) reached their highest values, recorded as 4931.97 kg·hm⁻² (2022), 6021.44 kg·hm⁻² (2023) and 2.19 kg·m⁻³ (2022), 2.39 kg·m⁻³ (2023), respectively. Based on the principal component analysis for comprehensive evaluation, the B2T2 treatment (polyacrylamide water-retaining agent applied at 60 kg·hm⁻²) achieved the highest comprehensive score in both years and could synergistically improve alfalfa yield and water-use efficiency. However, its applicability in the Yellow River irrigation region of Gansu Province and similar ecological areas still requires further verification through field trials. Full article

γ-Aminobutyric acid (GABA), a major inhibitory neurotransmitter, is known for its physiological functions in alleviating anxiety and improving sleep. Currently, high-yielding GABA food products are mainly obtained through screening wild-type high-producing strains (e.g., Saccharomyces cerevisiae isolated from Sichuan pickles yielding 0.67 g/L) or employing co-culture systems (e.g., Enterococcus faecium and Lactiplantibacillus plantarum reaching 6.35 g/L). While effective, these methods often rely on natural screening strains or multi-microbial interactions. This study employed CRISPR-Cas9 technology to knockout the UGA1 gene in Saccharomyces cerevisiae, a key gene responsible for GABA degradation. Starting from the low higher alcohol Saccharomyces cerevisiae SY-LH, we successfully constructed the recombinant strain SY-LHU. Remarkably, this study discovered a significant upregulation of GAD1 gene expression following UGA1 knockout, which further enhanced GABA synthesis capacity. Under optimal fermentation conditions (inoculum size 4 × 10⁷ cells/mL, wort concentration 10 °P, sugar addition 60 g/L, 30 °C for 10 days, and mixing the malt broth every 48 h), the validation fermentation was performed and the GABA content in the wort beverage reached 280.36 mg/L, representing a 385.4% increase compared to the pre-optimization level. Furthermore, sensory evaluation by a trained panel yielded a mean score of 88, with no significant off-flavors detected, demonstrating the product’s high consumer acceptance. This pioneering work provides a novel and feasible technical pathway for developing functional alcoholic beverages with sleep-aiding properties. Full article

Fruit flesh thickness is one of the key factors affecting the yield and quality of bitter melon, and its regulatory mechanisms remain unclear. One thick-flesh germplasm (KF) and one thin-flesh germplasm (NF) with significantly different flesh thicknesses were screened from 70 bitter melon germplasms. Through phenotypic surveys, combined metabolomic and transcriptomic analyses, and exogenous sugar treatments, the regulatory mechanisms on flesh thickness were preliminary investigated. The results showed that flesh thickness of the two germplasms remained stable during different years and seasons. Metabolomic and transcriptomic analyses revealed that fructose and mannose metabolism pathway significantly enriched in both omics datasets. The expression of key enzyme encoding genes from this pathway exhibited various expression patterns. In KF, most genes showed significantly higher expression levels than NF, with synergistic expression predominating among genes. Soluble sugar content was positively correlated with gene expression, while HXK, SDH, and TPI activities were negatively correlated with most genes, and FBP activity was positively correlated with most genes. Genes affect carbon source metabolic flux distribution by promoting sugar synthesis and inhibiting sugar respiration consumption. Exogenous sugar treatment exhibited germplasm-specific and concentration-dependent influence of gene expression, with KF primarily showing negative feedback and NF predominantly activating expression. Fruit flesh thickness was significantly positively correlated with the synergistic high expression of sugar metabolism genes and soluble sugar accumulation. This study provides a theoretical basis for molecular improvement of bitter melon fruit flesh thickness. Full article

Drought stress severely restricts agricultural productivity. Effective drought mitigation requires both improved rhizosphere water retention and enhanced nutrient availability. Poly-γ-glutamic acid (PGA) was expected to enhance water retention, while residue after evaporation (RAE) of 2-keto-L-gulonic acid fermentation was expected to supply labile carbon and promote nutrient mobilization. We hypothesized that their combined application would synergistically optimize the rhizosphere environment and enhance maize seedlings’ resistance to drought. A pot experiment was conducted to evaluate the growth of maize under simulated drought conditions, containing four treatments: control (C), RAE alone (R), PGA alone (P), and their combination (M). Results demonstrated that the M treatment synergistically promoted maize seedling growth, increasing the seedling growth index by 125% compared to the control. Co-application also synergistically enhanced the accumulation of osmotic adjustment substances (proline, soluble proteins, and soluble sugars) and ascorbic acid content, while reducing malondialdehyde (MDA) level. Furthermore, the M treatment markedly increased soil ammonium nitrogen and total organic carbon, thereby improving soil moisture and optimizing the rhizosphere conditions. Mantel analysis revealed that the M treatment restructured soil bacterial communities and enzyme activities by enhancing nutrient and organic carbon availability, which subsequently improved overall soil properties. These findings suggest that co-application of PGA and RAE improves maize seedling drought resilience and soil nutrient supply, offering a promising and economically viable strategy for sustainable agriculture in drought-prone regions by valorizing industrial by-products. Full article

Cover crops are crucial in conservation agriculture for preventing soil erosion. For Citrus unshiu production, rattail fescue (Vulpia myuros (L.) C.C. Gmel) is a popular cover crop because its growth season differs from the citrus season, minimizing nutrient competition. However, no studies have examined its effects on the seasonal concentrations of flavonoids and monoterpenes in citrus peels, which are often used as medical ingredients. In this study, our aim is to determine the effects of cover crops on the sugar content and medicinal properties of unripe citrus fruit during the growing season. Samples collected in 2022 were examined for the effects of cover crops on the sugar concentration of fresh pulp. In addition, samples were taken from three randomly selected trees in each cover crop treatment (0, 50, and 100% area coverage) at the thinning (July, August, and September) of 2023 and 2024 to analyze hesperidin and d-limonene concentrations using standard methods. The results showed that cover crops reduced the sugar concentration of fresh pulp but had no impact on hesperidin concentrations across all thinning events and had inconsistent effects on the d-limonene concentration. Hence, while the use of rattail fescue might negatively affect the sugar concentration of mature Citrus unshiu, the use of premature fruits for medical ingredients could compensate for this loss. Full article

The field production of tomato faces challenges regarding abiotic stress factors, which unfavorably impact fruit quality traits. Hedgerows, a form of agroforestry, offer a climate-resilient strategy to buffer temperatures and reduce the impact of direct wind stress on crop production. This study assessed the impact of hedgerow microclimate modulation effects on open-field tomato fruit quality, employing three genotypes (Roma, Ace55, and Szentlőrinckáta). Key quality traits (Total Soluble Solids (TSS), Titratable Acidity (TA), Sugar–Acid Ratio (SAR), Ferric-Reducing Antioxidant Power (FRAP), Total Phenolic Content (TPC), Chroma (C*), and Hue (h^o)) were measured over two harvests per season, in two consecutive years (2023–2024). Plots were positioned at five distances (3, 6, 9, 12, and 15 m from the hedge) on both windy and protected sides (W1–W5 and P1–P5, respectively, with 1 showing the closest position). We observed that the microclimate of the protected side was consistently warmer, with an average deviation from the reference temperature of +3.54 °C at mid-distances and +0.38 °C higher overall across both growing seasons. Results show that mid-distance zones (P3–P4, W3–W4) consistently exhibited the highest C* (up to 39.44) at W4 and TSS values at W1 (7.00 °Bx). Protected sides favored higher TA at P3 (0.70%) and Hue (h^o) values at P3 with (53.06 ± 0.30) with Ace55 and SAR at P3 (16.35) with Szentlőrinckáta. Windy sides significantly enhanced FRAP and TPC, with the Szentlőrinckáta genotype exhibiting the highest antioxidant capacity at W1 (23.67 mg AAE 100 g⁻¹, FRAP) and TPC (244.17 mg GAE 100 g⁻¹). At W4, Roma showed a 9.4% increase in TPC in the second harvest, while Ace55 showed the highest FRAP values during late-season sampling, highlighting genotype-specific antioxidant resilience under contrasting microclimates. These findings suggest that mid-distance zones and microclimatic variation between windy and protected sides remarkably influence fruit quality traits and antioxidant profiles. Full article

This study investigates the degradation characteristics, pathways, and mechanisms of ochratoxin A (OTA) by Weizmannia coagulans CGMCC 9951 (W. coagulans CGMCC 9951), as well as its detoxification effect on Cornus officinalis pulp through fermentation. The strain efficiently degraded 300 ng/mL of OTA within 72 h (98% degradation) under optimal conditions of 37 °C, pH 5.0, and 180 rpm. Active degradation substances were primarily localized in the cell-free supernatant (CF). The degradation activity was significantly inhibited by heat treatment, proteinase K, EDTA, Cu²⁺, and organic reagents, suggesting an enzymatic mechanism. UHPLC-MS and MS/MS analysis indicated that OTA appears to be degraded to a product consistent with ochratoxin α (OTα). Based on homology to known OTA-degrading carboxypeptidases, the gene encoding WGU28473.1 was selected, expressed in E. coli, and confirmed to possess OTA-degrading activity. Molecular docking suggested potential interactions between the enzyme and OTA. Under optimal conditions, co-fermentation with Cornus officinalis pulp contaminated with 300 ng/mL OTA for 96 h resulted in a 74% degradation of OTA. The fermentation process increased the pulp’s sugar content and ABTS⁺ free radical scavenging capacity, reduced acidity, and improved the safety of the pulp. These findings demonstrate that W. coagulans CGMCC 9951 efficiently degrades OTA and improves pulp quality, highlighting its potential as a starter culture for detoxifying OTA-contaminated food. Full article

Gold nanoparticles (AuNPs) have numerous applications in science and industry. Therefore, their potential phytotoxicity should be investigated. Garden cress (Lepidium sativum L.) is a useful model plant for assessing the effects of chemicals released into the environment. The aim of this study was to prepare alginate gels containing AuNPs for plant exposure experiments, evaluate their physicochemical properties, and determine their effects on selected biochemical parameters of garden cress seedlings. Gold nanoparticles were synthesized in sodium alginate at an initial concentration of 50 mg/L, using xylose and maltose as reducing agents. The gels were diluted with distilled water to obtain AuNP concentrations of 5 and 25 mg/L. Garden cress seeds were placed on filter paper soaked with the tested formulations, while distilled water and sodium alginate solutions without AuNPs served as controls. After 5 days of incubation at 20 °C under light conditions, the plant material was collected and selected bioactive compounds were determined. AuNP-containing gels significantly affected the biochemical status of the seedlings. In particular, AuNPs synthesized with xylose at 25 mg/L significantly increased the contents of photosynthetic pigments and total polyphenolic compounds. All tested AuNP formulations increased the antioxidant activity of seedlings, suggesting the activation of abiotic stress-related defense responses, however, direct markers of oxidative damage were not assessed in the present study. Overall, the results indicate that alginate-based AuNPs can modify selected biochemical parameters in garden cress seedlings, and these effects depend on nanoparticle concentration and reducing sugar used during synthesis, which may be relevant for the future development of plant-targeted nanomaterials for agricultural applications. Full article

Excessive nitrate accumulation in leafy vegetables presents significant health risks, requiring sustainable strategies to optimize yield while minimizing nitrogen-related anti-nutritional factors in controlled environments. This study investigated the effects of varying LED light intensities 236.9 µmol·m⁻²·s⁻¹ (high), 189.8 µmol·m⁻²·s⁻¹ (medium), and 117.6 µmol·m⁻²·s⁻¹ (low) on nitrates (NO₃⁻) dynamics, growth, and biochemical composition in two Lollo Rossa lettuce cultivars, Carmesi and Carnelian, grown in NFT hydroponic systems. Conducted under constant temperature (20/18 °C day/night) and CO₂ (625 µmol·mol⁻¹) to isolate light’s influence, the experiment used a replicated design with three replicates per treatment, each including two cultivars. Morphological traits (plant height, rosette diameter, leaf number, biomass, root development) and biochemical parameters (nitrate and sugar contents) were assessed via mean comparisons, trends, and correlations. Results demonstrated that higher light intensity significantly suppressed nitrate accumulation in lettuce through enhanced assimilation and dilution effects linked to increased growth. Nitrate levels dropped to 2091.67 mg kg⁻¹ from 2443.33 mg kg⁻¹ in Carmesi and 2013.33 mg kg⁻¹ from 2515.00 mg kg⁻¹ in Carnelian. Negative correlations were observed between nitrate content and growth parameters: nitrates vs. fresh biomass (r = −0.89); nitrates vs. plant height (r = −0.79). Concurrently, it boosted carbohydrate content (Carmesi: 3.03 °Brix; Carnelian: 3.08 °Brix) and promoted vigorous growth, with Carmesi achieving superior metrics under high light (height: 22.12 cm, rosette diameter: 29.87 cm, fresh biomass: 206.88 g, root biomass: 19.58 g) compared to low light (17.45 cm height, 183.42 g biomass). Carnelian exhibited similar trends but prioritized root elongation. These findings underscore light’s role in regulating nitrate transporters and assimilation enzymes (e.g., nitrate reductase), offering a low-cost approach to reduce nitrate risks, enhance nutritional quality, and improve yield in controlled horticultural systems (CHS). Full article

Consumer interest in low-SO₂ white wines is increasing; however, such approaches may reduce compositional and sensory predictability. This study evaluates how three fermentation strategies—SO₂ addition and Saccharomyces cerevisiae ES181 inoculation (SO₂Sc), spontaneous fermentation (NoSO₂-Spont), and inoculation with S. cerevisiae ES181 without SO₂ addition (NoSO₂Sc)—shape the chemical profile, polyphenolic composition, colour, microbiological status, and sensory perception of ‘Solaris’ wines relative to the must (reference). A single batch of ‘Solaris’ must (one press run) was split into three variants and fermented under identical temperature conditions (12 ± 0.5 °C), followed by cool ageing and natural sedimentation prior to bottling. Basic oenological parameters, selected fermentation by-products, viable yeast counts, CIE Lab colour, targeted polyphenolics (phenolic acids, flavonols, flavan-3-ols, and stilbenes), PCA of by-products, and blind sensory evaluation were assessed. The NoSO₂-Spont variant showed reduced fermentation completeness (higher residual sugars and lower ethanol) and the highest volatile acidity, together with elevated glycerol and several higher alcohols, and received the lowest sensory ratings. The SO₂Sc variant yielded the most controlled outcome, with the lowest volatile acidity, the brightest colour (higher L*, lower b*), and the highest sensory acceptance. The NoSO₂Sc variant produced intermediate sensory scores and a higher total phenolic content; however, volatile acidity remained high and viable yeast counts were the greatest, indicating increased susceptibility to microbiological activity during extended pre-bottling handling. Overall, the SO₂Sc strategy provides the greatest chemical stability and sensory acceptance, whereas low-SO₂ regimes require a hurdle approach (oxygen control, residual sugar management, hygiene, and stabilisation) to limit spoilage development and post-bottling refermentation. Full article

Drought stress critically impacts plant growth and productivity. The bZIP transcription factor family is crucial for abiotic stress responses, yet its role in larch drought tolerance remains unclear. This study identified 19 bZIP genes in Larix kaempferi (Lamb.) Carr. and characterized LkbZIP4. Bioinformatics analysis classified it into the A subgroup. Subcellular localization and yeast two-hybrid assays confirmed that it is a nucleus-localized transactivator. Expression pattern analysis revealed that LkbZIP4 was highly specifically expressed in roots and was significantly induced by drought stress. A series of transgenic overexpression lines was successfully established through Agrobacterium tumefaciens-mediated method, using embryogenic callus of hybrid larch (L. kaempferi × L. gmelinii). Under 7% PEG-induced drought stress, LkbZIP4-overexpressing transgenic calli displayed enhanced drought tolerance relative to wild-type. This was evidenced by better growth, higher biomass, and reduced membrane damage, indicated by lower malondialdehyde content and relative electrolyte leakage. Meanwhile, these transgenic calli accumulated higher levels of osmoregulatory substances, including proline and soluble sugars, along with enhanced activities of antioxidant enzymes including superoxide dismutase and peroxidase. Our results indicate that LkbZIP4 functions to promote drought tolerance in larch, likely through the enhancement of osmotic adjustment and oxidative defense mechanisms. Full article