Search Results (185)

Phytoalexins are antimicrobial compounds of diverse chemical classes whose production is triggered in plants in response to pathogen infection. This study demonstrated that spraying with a celery flavonoid-rich extract (CFRE) or a spinach flavonoid-rich extract (SFRE) enhanced the production of phytoalexins in cucumber leaves artificially infected with powdery mildew incited by Podosphaera fusca. High-performance liquid chromatographic (HPLC) analysis revealed a noticeable increase in the content of phenolic acids, including caffeic acid, ellagic acid, ferulic acid, gallic acid, p-coumaric acid, and syringic acid, as well as the flavonoid rutin in both non-inoculated and inoculated leaves of cucumber seedlings treated with CFRE and SFRE, compared to healthy untreated leaves used as a control. Fluorescence microscopy revealed the accumulation of phenolic acid compounds in chloroplasts and at the periphery of epidermal cells. Overall, results suggest the reduced severity of P. fusca infection following the application of CFRE and SFRE in cucumber leaves could be due, at least in part, to the production of phytoalexins of polyphenolic nature. These findings provide insights into the mechanisms of systemic resistance induced by CFRE and SFRE. Moreover, they confirm these two natural flavonoid-rich products could be promising alternatives to synthetic chemical fungicides for the safe and ecofriendly control of cucumber powdery mildew. Full article

Microbial contamination of food can lead to faster spoilage and infections. Therefore, disinfection processes are required that have a low detrimental effect on the nutritional content. Concerning radiation disinfection, two spectral ranges have recently become important. The Far-UVC spectral range, with a wavelength below 230 nm and visible violet light. In this study, leaf spinach was used to investigate the extent to which these radiations inactivate Escherichia coli, but also to determine if the vitamin C or chlorophyll content was reduced. Frozen spinach leaves (Spinacia oleracea) were contaminated with E. coli × pGLO and irradiated with either a 222 nm krypton chloride lamp or 405 nm LEDs. The achieved bacterial reduction was determined by plating the irradiated samples on agar plates and subsequent colony counting. The vitamin C concentration was determined by means of redox titration, and the concentrations of chlorophyll a and chlorophyll b were determined using spectrometry. Both irradiations exhibited a strong antimicrobial impact on E. coli. The average log reduction doses were about 19 mJ/cm² (222 nm) and 87 J/cm² (405 nm), respectively. The vitamin C concentration decreased by 30% (222 nm) or 20% (405 nm), and the chlorophyll concentrations decreased by about 25%. Both irradiation approaches are able to substantially reduce microorganisms on spinach leaves by two orders of magnitude, but this is associated with a reduction in the nutrient content. Full article

Spinach (Spinacia oleracea L.) is an important leafy vegetable but is vulnerable to viral infections that significantly affect its quality and yield. In this study, we identified virus-infected spinach exhibiting typical symptoms with yellowing, wrinkling, and mottling in Beijing. But conventional RT-PCR screening for twelve common plant viruses yielded negative results. Then, using transcriptome sequencing along with a de novo assembly approach, we obtained the complete viral genome, which consists of RNA1 (5916 nucleotides) and RNA2 (3576 nucleotides). BLASTN analysis against the NCBI viral genome database revealed high homology with broad bean wilt virus 2 (BBWV2), leading us to designate this isolate as BBWV2-SP (GenBank accession numbers PV102464 and PV102465). Phylogenetic analysis indicated that BBWV2-SP shares 96.69% nucleotide sequence identity with a Liaoning isolate from Chenopodium album MN786955 and clusters within the Chinese evolutionary lineage. We developed primers targeting the conserved region of the RNA2 coat protein, amplifying a 478-base-pair product. All symptomatic spinach samples tested positive, while asymptomatic controls remained negative, confirming the causal relationship between BBWV2-SP and the observed disease symptoms. This study provides the complete genome assembly of the spinach isolate BBWV2-SP and establishes a molecular detection protocol for BBWV2 in spinach. These findings offer essential technical support for field monitoring, epidemiological surveillance, and disease control strategies, while also enhancing our understanding of BBWV2′s genetic diversity and mechanisms of pathogenicity. Full article

The important role of antibiotics cannot be overestimated, as human health relies heavily on them for the treatment of infectious diseases. In this study, the antimicrobial susceptibility profiles of pathogens isolated from spinach (Spinacia oleracea) and cabbage (Brassica oleracea) collected from Free State Province were investigated. A total of 38 isolates representing 10 species, Enterobacter cloacae (5.3%), Staphylococcus aureus (13.2%), Micrococcus luteus (5.3%), Staphylococcus sciuri (5.3%), Acinetobacter haemolyticus (5.3%), Burkholderia cepacia (15.8%), Pseudomonas luteola (15.8%), Escherichia coli (18.4%), Citrobacter freundii (5.3%), and Serratia marcescens (10.5%), were confirmed by the Analytical Profile Index (API). We evaluated antibiotic resistance patterns of 38 unduplicated isolates using the disk diffusion method. As a result, E. coli (18.4%), B. cepacia (15.8%), P. luteola (15.8%), S. aureus (13.2%), and S. marcescens (10.5%), as well as 5.3% each for E. cloacae, M. luteus, S. sciuri, A. haemolyticus, and C. freundii, showed resistance to tested antibiotics. The majority (84%) of the isolates showed resistance to tetracycline, and penicillin had a value of 71%. A total of 79% of the antibiotic-resistant isolates demonstrated multidrug resistance (MDR) to several classes such as β-lactams, chloramphenicol, tetracycline, aminoglycosides, and macrolides. The results highlight the importance of monitoring the microbiological quality of leafy greens as they contain antibiotic-resistant bacteria that could affect human health when consumed. Full article

Spinach (Spinacia oleracea L.), a globally consumed, nutrient-dense vegetable, contains diverse vitamins and minerals. However, elevated temperatures can constrain yield by interrupting leaf development and photosynthetic efficiency. The mitochondrial transcription termination factor (mTERF) family, which regulates organellar gene expression, plays crucial roles in plant growth and photosynthetic regulation. Thus, characterization of the spinach mTERF (SomTERF) family is critical for elucidating thermotolerance mechanisms in this crop. In this study, we systematically identified 31 SomTERF genes from the spinach genome, which are distributed across five chromosomes and nine unassembled genomic scaffolds. Subcellular localization predictions indicated that these proteins predominantly target chloroplasts and mitochondria. Conserved domain analyses confirmed that all SomTERF proteins possess canonical mTERF domains and ten conserved motifs. Phylogenetic clustering segregated these proteins into nine distinct subgroups (I–IX), with significant divergence observed in gene copy numbers among subgroups. Cis-element screening identified an abundance of heat-, cold-, and hormone-responsive motifs within SomTERF promoter regions. Notably, seven members (including SomTERF5) exhibited pronounced enrichment of heat shock elements (HSEs). Organ-specific expression profiling revealed preferential leaf expression of these seven genes. Comparative RT-qPCR in heat-sensitive (Sp73) and heat-tolerant (Sp75) cultivars under thermal stress demonstrated genotype-dependent expression dynamics. Functional validation of SomTERF5 was achieved through cloning, and transgenic Arabidopsis overexpressing SomTERF5 showed significantly enhanced thermotolerance, as evidenced by improved survival rates following heat treatment. Yeast two-hybrid (Y2H) assays further revealed physical interaction between SomTERF5 and SopTAC2. This study provides a comprehensive foundation for understanding mTERF-mediated developmental regulation and advanced molecular breeding strategies for developing heat-resilient spinach varieties. Full article

Background: Equally with other indigenous green leafy vegetables, Solunum nigrum L. has been widely consumed by the VhaVenda tribe found in the Limpopo Province of South Africa since ancient times as a source of food diversification due to its higher-quality nutritional value, sustainability, food security, and medicinal benefits. It is mostly cultivated from seeds in seedling trays and transplanted in the open field, and at the maturity stage, marketing and distribution are mainly conducting through informal markets (i.e., street vendors). However, recently, it can be found in selected supermarkets and commercial grocery stores in South Africa. The leaves and young shoots of S. nigrum are cooked solely and/or as a supplementary vegetable with Brassica rapa L. subsp. chinensis (Chinese cabbage), Spinacia oleracea L. (spinach), Amaranthus graecizans L. (green amaranth), Solanum lycopersicum L. (tomato), and/or cooking oil for flavor. Objective: Contrary to other green leafy vegetables, few studies have been conducted on the metabolites released by S. nigrum and the influence of growing conditions on the metabolites thereof. Method: A ¹H-nuclear magnetic resonance tool was used to identify the untargeted metabolites released by S. nigrum, and spectra were phase-corrected and binned with MestReNova and statistically analyzed with SIMCA 18.0.2. Results: The findings showed that a total of 12 metabolites were detected between the growing conditions. Eleven similar metabolites, such as glycocholate, chlorogenate (human health benefits), caffeine for its bitter taste, choline, 3-Chlorotyrosine (antidiabetic, blood pressure), etc., and a few vital soluble sugars, were detected in S. nigrum samples grown in the open field and greenhouse-cultivated. Glucose was exclusively detected in the S. nigrum grown under greenhouse conditions. Full article

The interaction between advanced glycation end products (AGEs) and their RAGE receptor (AGEs/RAGE axis) triggers several signaling pathways that lead to the development of diabetic nephropathy (DN). One of the most studied AGEs is Nε-(1-Carboxymethyl)-L-lysine (CML). Spinacia oleracea is an edible plant with beneficial health properties, but its effect on the AGE/RAGE axis in kidney damage is unknown. Objective: We aimed to investigate the functional role of spinach methanolic extract (SME) on kidney damage in diabetic rats associated with the CML/RAGE axis. Methods: Forty adult male Wistar rats were used in this study and divided into four groups: control rats (CTRL), SME-administered CTRL (400 mg/kg; SME), streptozotocin-induced diabetic nephropathy rats (STZ), and SME-treated STZ (STZ-SME); treatments were administered daily. After 12 weeks, serum AGEs, creatinine in urine, and lipid peroxidation in kidneys were measured. The distribution and expression levels of inflammatory and fibrotic mediators and RAGE signaling were evaluated through immunohistochemistry (NOX4, CML, RAGE, nuclear NF-κB, TNF-α, IL-1β, TGF-β1, SMAD2/3, CTGF, and a-SMA) and immunolocalization of CML/RAGE. Results: Glycoside flavonoid derivatives, such as patuletin and spinacetin, were primarily identified in the extract. Kidneys from the STZ group showed altered morphology, dead cells in the proximal tubules, and increased oxidative stress markers; notably, these effects were improved by SME treatment (STZ-SME). The STZ-SME group showed a lower staining intensity for CML and RAGE, which was associated with a decrease in the expression of inflammatory and fibrotic factors compared with the STZ group. In all groups, the distribution of these markers varied among proximal tubule, glomerular, and interstitial cells. Conclusions: SME treatment may help to prevent or delay kidney damage in diabetic rats by regulating inflammatory and fibrotic processes associated with the AGEs/RAGE pathway, a mechanism involved in the development of nephropathy. Full article

Growing spinach year-round via greenhouse hydroponics in warm climates can be challenging because of the intolerance of many spinach cultivars to heat. Root-zone cooling in hydroponic systems in warm climates may be a promising cooling method to alleviate heat stress; however, its effectiveness is still unknown in spinach plants. This study aimed to investigate the impact of root-zone cooling on the growth and physiological responses of four spinach cultivars (‘Lakeside’, ‘Hammerhead’, ‘Mandolin’, and ‘SV2157’) grown in deep water culture hydroponic systems in a greenhouse during the summer season in two growing cycles. The experiment consisted of the following three root-zone temperatures (RZTs): Control (ambient water temperature), RZT24 (24 °C), and RZT21 (21 °C). Among the four cultivars, ‘SV2157’ performed equally regardless of the treatment, demonstrating superior heat tolerance versus the other three cultivars. ‘Mandolin’ exhibited the greatest benefit from root-zone cooling, with increases in shoot dry weights of 87% and 94% under RZT24 and RZT21, respectively, compared to those under control treatment. Additionally, total leaf areas significantly increased under the two root-zone cooling treatments. ‘Lakeside’ and ‘Hammerhead’ generally benefited from root-zone cooling, although the magnitude of growth increases was small or statistically insignificant. However, ‘Lakeside’ and ‘Hammerhead’ were highly responsive to lower ambient air temperatures, as evidenced by increases of 121% and 90%, respectively, in shoot fresh weights across the treatments in Cycle 2 (average air temperature of 24.7 °C) compared to those in Cycle 1 (29.3 °C). Physiological responses to root-zone cooling varied among cultivars, with ‘SV2157’ exhibiting the highest chlorophyll, carotenoid, and anthocyanin levels. Higher total phenolic contents under control treatment in Cycle 1 in all three cultivars except for ‘SV2157’ suggested greater reactive oxygen species production, indicating oxidative stress. Root-zone cooling reduced oxidative stress indicators, including mortality (%), hydrogen peroxide content, and malondialdehyde content, and minimized cell leakage. Based on plant growth, physiological and biochemical traits, and electricity consumption, cooling the root zone to 24 °C rather than 21 °C is recommended for hot summers with high air temperatures. Full article

This study evaluates the effects of ultraviolet (UV) radiation (UVA, UVB, and UVC) on the postharvest quality and nutritional stability of fresh-cut spinach during cold storage. Spinach samples were exposed to UV treatments for 0, 5, or 10 min and stored at 4 ± 1 °C with 85 ± 5% relative humidity for up to 10 days. Weight loss, dry matter content, total soluble solids, electrical conductivity, pH, respiration rate, color parameters, ash content, and mineral composition were assessed. The results showed that UVB-treated spinach had the lowest weight loss (0.52%), compared to UVC-treated (0.75%) and control (0.82%) samples. The dry matter content was highest in UVB-treated samples (9.56%) and lowest in UVC-treated samples (8.62%). UVC exposure increased electrical conductivity (112 µS cm⁻¹), indicating greater ion leakage. UVA and UVB treatments preserved the chlorophyll content (SPAD values of 34.5 and 37.0, respectively) and reduced the respiration rates. These physiological responses are indicative of delayed senescence and improved storage potential. UVB-treated samples retained higher potassium (4040 mg 100 g⁻¹), calcium (1445 mg 100 g⁻¹), and phosphorus (375 mg 100 g⁻¹), while UVC-treated samples showed greater mineral loss. Hierarchical clustering analysis revealed distinct metabolic responses among UV treatments. This study provides a novel comparative assessment of UVA, UVB, and UVC effects on fresh-cut spinach, demonstrating UVB as the most effective non-chemical method for enhancing shelf life while preserving nutritional quality. Full article

This is a pioneering study on the main drainage system in Gujranwala District, where untreated mixed wastewater is discharged and subsequently used for vegetable irrigation, leading to potential health and environmental risks. This study seeks to develop the spatial pattern of toxic metal accumulation in soil across an 11 km stretch of land used for vegetable cultivation. By using 90 samples of mixed wastewater and sludge, as well as 10 quadruplicate samples of rhizospheric soils and crops from ten vegetable fields, it was observed that the concentrations of Cr, Cu, Cd, Zn, Fe, Pb, Mg, and Ni in cauliflower (Brassica oleracea var. botrytis L.), coriander (Coriandrum sativum L.), radish (Raphanus sativus L.), mustard (Brassica juncea L.), spinach (Spinacia oleracea L.), meadow clover (Trifolium sp. L.), sorghum (Sorghum bicolour L.), garlic (Allium sativum L.), brinjal (Solanum melongena L.), and mint (Mentha L.) were beyond the permissible limits set by the FAO/WHO, 2001. The declining trend of the toxic metal concentrations in the effluent was Mg > Cr > Ni > Zn > Pb > Cd > Cu > Fe, and in sludge, soil, and plants, it varied in the order of Mg > Fe > Cr > Ni > Zn > Pb > Cd > Cu. Radish, mint, and brinjal had the highest quantities of toxic metals. The spatial pattern of toxic metals was determined by using proximity interpolation, Inverse Distance Weighted (IDW), the fine tuning of the interpolation characteristics, and the kriging of selected sample variograms. Toxic metals were found in the following order: plants > soil > sludge > effluents. The most prevalent cause of metal pollution was soil irrigation with polluted water. This study provides crucial information about the extent of contamination, which could help in the identification of public health risk, the assessment of environmental impacts, and also sustainable water management. Full article

Global trends in health, climate, and population growth drive the demand for high-nutrient plants like spinach, which thrive under controlled conditions with minimal resources. Despite technological advances in agriculture, current systems often rely on traditional methods and need robust computational models for precise plant growth forecasting. Optimizing vegetable growth using advanced agricultural and computational techniques, addressing challenges in food security, and obtaining efficient resource utilization within urban agriculture systems are open problems for humanity. Considering the above, this paper presents an enclosed agriculture system for growth and modeling spinach of the Viroflay (Spinacia oleracea L.) species. It encompasses a methodology combining data science, machine learning, and mathematical modeling. The growth system was built using LED lighting, automated irrigation, temperature control with fans, and sensors to monitor environmental variables. Data were collected over 60 days, recording temperature, humidity, substrate moisture, and light spectra information. The experimental results demonstrate the effectiveness of polynomial regression models in predicting spinach growth patterns. The best-fitting polynomial models for leaf length achieved a minimum Mean Squared Error (MSE) of 0.158, while the highest MSE observed was 1.2153, highlighting variability across different leaf pairs. Leaf width models exhibited improved predictability, with MSE values ranging from 0.0741 to 0.822. Similarly, leaf stem length models showed high accuracy, with the lowest MSE recorded at 0.0312 and the highest at 0.3907. Full article

Using beneficial microorganisms as biostimulants is a promising strategy to enhance crop growth and productivity in hydroponic systems. Trichoderma asperellum has demonstrated plant growth-promoting effects in soil cultivation; however, its efficacy in hydroponic Deep-Water Culture (DWC) systems remains underexplored. This research evaluated the effect of T. asperellum strains TaMFP1 and TaMFP2 on the growth, nutrient uptake, and visual quality of hydroponically grown spinach cv. Stella Plus F-1 (Spinacia oleracea L.). A randomized complete design was used, comparing inoculated plants with a control and a commercial Trichoderma harzianum product. After 28 days, the results showed that T. asperellum significantly increased plant height (23.1%), collar diameter (21.8%), root length (39.6%), leaf area (22.0%), number of leaves (18.05), and fresh biomass accumulation (23.5%) compared to non-inoculated plants. Furthermore, inoculation with TaMFP1 improved spinach yield by 34.5%, while nutrient analysis indicated enhanced phosphorus and calcium uptake. No significant changes were observed in photosynthetic pigment concentrations, and the visual quality of the harvested spinach was unaffected. These findings highlight the potential of T. asperellum as a sustainable biostimulant in hydroponic spinach production. These results contribute to developing beneficial microorganism-based strategies to enhance the sustainability of hydroponic agriculture. Full article

The paramount objectives of this study were to analyze the beneficial role of the circadian clock in alleviating drought stress in an essential green leafy horticultural crop, spinach (Spinacia oleracea), and to attain knowledge on drought-stress adaptation for crop productivity. From dawn to dusk, a circadian core oscillator-based defense mechanism was noticed in relation to the strength of the chloroplast proteome and transcriptome, and the defense hormone fused it along with the molecular physiology using genotypes “Malav Jyoti” and “Delhi Green”. A photo-periodic rhythmicity containing a 4 h time interval (morning–evening loop) for 12 h in spinach was exhibited under drought-stressed (day-5) and drought re-irrigated (day-10) conditions. The circadian oscillator controlled 70% of the major part of growth and physiological measures such as the biomass, plant height, leaf-relative water content, and the shoot–root ratio under drought stress. Contrarily, drought stress resulted in the upregulation of antioxidative activities and stress markers, whereas it was diversified and maintained in the case of the re-irrigated state at certain rhythmic time intervals of the circadian clock. The physiological parameters we examined, such as net photosynthesis, transpiration, stomatal conductance, and antioxidative enzymes, exhibited the role of the circadian clock in drought stress by showing 80–90% improvements found in plants when they were re-watered after drought stress based on their circadian oscillations. Based on the physiological results, 10 a.m. and 2 p.m. were disclosed to be the rhythmic times for controlling drought stress. Moreover, an extensive study on a gene expression analysis of circadian clock-based genes (CCA1, LHY, TOC1, PRR3, PRR5, PRR7, PRR9, and RVE8) and drought-responsive genes (DREB1, DREB2, and PIP1) depicted the necessity of a circadian oscillator in alleviating drought stress. Hence, the findings of our study allowed for an intense understanding of photo-periodic rhythms in terms of the morning–evening loop, which is in line with the survival rate of spinach plants and occurs by altering cellular ROS-scavenging mechanisms, chloroplast protein profiles, gene regulation, and metabolite concentrations. Full article

The utilization of red and blue light-emitting diode (LED) lights for cultivating leafy vegetables in closed plant factories has increased in recent years. This study examined the growth and biosynthesis of functional compounds in twelve Spinacia accessions, including cultivars and wild relatives, under the irradiation of fluorescent light and three different red-to-blue LED light combinations (red:blue = 1:1, 1:3, and 3:1). Results showed that, except for the three examined Japanese cultivars, the fresh weight of most spinach accessions increased when red light comprised 50–75% of the light’s spectral composition. This indicated the vital role of the red-light photoreceptor phytochrome in inducing plant growth. The contribution of blue-light photoreceptors was also notable. Significant variations in the accumulation of amino acids and sugars were observed in specific accessions. The effects of spectral photons on the primary metabolite pathways were probably the leading causes of these variations. Some critical enzymes in the Gamma-aminobutyric acid (GABA) shunt cycle and the asparagine and glycolysis pathways were suggested as rate-limiting enzymes, which determined the biosynthesis of functional compounds. Among the examined Spinacia accessions, ‘CGN09429’, ‘CGN09511’, and the wild S. turkestanica ‘CGN25013’ were identified as potential breeding materials, while red:blue = 1:1 was determined as the optimal red-to-blue ratio for spinach growth in a closed-cultivation system. Full article

Due to an increased demand for natural food additives, clove oil was assessed as a natural alternative to chemical disinfectants in produce washing. This study assessed the antimicrobial activity of 5 and 10% (v/v) clove oil-amended wash liquid (CO) using a zone of inhibition (ZIB) test and determined the time required to completely inactivate pathogenic bacteria using bacterial death curve analysis. A washing experiment was used to evaluate CO’s ability to inhibit bacterial growth on inoculated RTE spinach and in the wash water. The findings showed that Shigella flexneri, Salmonella Typhimurium, and Salmonella enterica recovery were completely inhibited within 5 min. Escherichia coli and Staphylococcus aureus recovery were completely inhibited at 10 and 30 min, respectively. The ZIB test showed that 5% CO had the highest inhibitory effect on both Salmonella strains and E. coli with approximately 10 mm ZIB diameter. Additionally, 5% CO completely inactivated all bacterial strains on spinach samples and in the wash water except for S. aureus. A total of 80 mg/L peracetic acid (PAA) resulted in >2log CFU/mL recovery on experimental washed samples. These findings suggest that 5% CO was highly effective in inhibiting microbial growth on RTE spinach, potentially contributing to sustainable food safety and shelf-life extension strategies. Full article