Effects of UV-B radiation on the isoflavone accumulation and physiological-biochemical changes of soybean during germination: Physiological-biochemical change of germinated soybean induced by UV-B

Insight into the effect of wheatgrass powder on steamed bread properties: Impacts on gluten polymerization and starch gelatinization behavior

This study investigates the use of wheatgrass powder (WGP) as a functional ingredient in steamed bread, focusing on its effects on the nutritional composition and key biological macromolecules, specifically gluten and starch. Wheatgrass harvested at 8 days demonstrated optimal bioactive content, enhancing steamed bread quality. The incorporation of WGP (2.5 % and 5 %) reduced loaf volume and increased firmness and chewiness while improving flavor and taste. WGP also suppressed starch gelatinization, decreased thermal stability, and altered gluten polymerization by reducing the polymerization of α- and γ-gliadin into glutenin. Scanning electron microscopy (SEM) analysis revealed that WGP disrupted the gluten-starch matrix, leading to a fragmented gluten network and reduced starch gelatinization, which contributed to the increased firmness and chewiness of steamed bread. These findings highlight the potential of WGP as a functional ingredient for wheat-based products and fill the gap by providing WGP insights into the optimization of dough properties and the underlying molecular interactions involving proteins and starch.

Optimization of Ultraviolet-B Treatment for Enrichment of Total Flavonoids in Buckwheat Sprouts Using Response Surface Methodology and Study on Its Metabolic Mechanism

Buckwheat possesses significant nutritional content and contains different bioactive compounds, such as total flavonoids, which enhance its appeal to consumers. This study employed single-factor experiments and the response surface methodology to identify the optimal germination conditions for enhancing the total flavonoid content in buckwheat sprouts through ultraviolet-B treatment. The research showed that buckwheat sprouts germinated for 3 days at a temperature of 28.7 °C while being exposed to ultraviolet-B radiation at an intensity of 30.0 μmol·m-2·s-1 for 7.6 h per day during the germination period resulted in the highest total flavonoid content of 1872.84 μg/g fresh weight. Under these specified conditions, ultraviolet-B treatment significantly elevated the activity and gene expression levels of enzymes related to the phenylpropanoid metabolic pathway, including phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, 4-coumarate coenzyme A ligase, and chalcone isomerase. Ultraviolet-B treatment caused oxidative damage to buckwheat sprouts and inhibited their growth, but ultraviolet-B treatment also enhanced the activity of key enzymes in the antioxidant system, such as catalase, peroxidase, superoxide dismutase, and ascorbate peroxidase. This research provided a technical reference and theoretical support for enhancing the isoflavone content in buckwheat sprouts through ultraviolet-B treatment.

UV-B Radiation Exhibited Tissue-Specific Regulation of Isoflavone Biosynthesis in Soybean Cell Suspension Cultures

Isoflavones, a class of substances with high biological activity, are abundant in soybeans. This study investigated isoflavone biosynthesis in soybean cell suspension cultures under UV-B radiation. UV-B radiation enhanced the transcription level and activity of key enzymes involved in isoflavone synthesis in cell suspension cultures. As a result, the isoflavone contents significantly increased by 19.80% and 91.21% in hypocotyl and cotyledon suspension cultures compared with the control, respectively. Meanwhile, a significant difference was observed in the composition of isoflavones between soybean hypocotyl and cotyledon suspension cultures. Genistin was only detected in hypocotyl suspension cultures, whereas glycitin, daidzein, and genistein accumulated in cotyledon suspension cultures. Therefore, UV-B radiation exhibited tissue-specific regulation of isoflavone biosynthesis in soybean cell suspension cultures. The combination of suspension cultures and abiotic stress provides a novel technological approach to isoflavone accumulation.

The effect of different LED wavelengths on the components and biosynthesis of isoflavonoid in sprout Astragalus membranaceus

An artificial light source is the optimal element for studying the usability of the medicinal plant Astragalus membranaceus as a sprout vegetable. Based on artificial light source conditions, formononetin (FO) level was the highest (2.6 mg/L) in A. membranaceus exposed to white light emitting diode (LED) light, and calycosin (CA) level was the highest (3.09 mg/L) in the plant exposed to red LED light. According to the publicly available transcriptome data of LED-exposed sprout A. membranaceus LED, reference genes related to the content enhancement of FO, an isoflavone compound, and those related to the content enhancement of CA were selected. The expression patterns of these genes were assayed using qPCR. Among the genes related to FO enhancement, Gene-225190T showed the highest mRNA levels in cells of LED-white light-exposed sprout A. membranaceus; among the genes related to CA enhancement, Gene_042770T showed the highest expression under red LED light. Most genes related to the overall biosynthesis regulation of flavonoids of the upper concept of isoflavone were highly expressed in response to red LED light, and the transcriptional level of 4CL in response to red LED light was the highest. Based on these results, the artificial light sources that regulated the FO and CA contents in sprouts A. membranaceus were white and red LED lights, and the selected reference genes were capable of regulating isoflavone biosynthesis.

Combined analysis of inorganic elements and flavonoid metabolites reveals the relationship between flower quality and maturity of Sophora japonica L

Flos Sophorae (FS), or the dried flower buds of Sophora japonica L., is widely used as a food and medicinal material in China. The quality of S. japonica flowers varies with the developmental stages (S1-S5) of the plant. However, the relationship between FS quality and maturity remains unclear. Inductively coupled plasma optical emission spectrometry (ICP-OES) and ultra-high performance liquid chromatography coupled with electrospray ionization-triple quadrupole-linear ion trap mass spectrometry (UPLC-ESI-Q TRAP-MS/MS) were used to analyze inorganic elements and flavonoid metabolites, respectively. A combined analysis of the inorganic elements and flavonoid metabolites in FS was conducted to determine the patterns of FS quality formation. Sixteen inorganic elements and 173 flavonoid metabolites that accumulated at different developmental stages were identified. Notably, 54 flavonoid metabolites associated with the amelioration of major human diseases were identified, and Ca, P, K, Fe, and Cu were postulated to influence flavonoid metabolism and synthesis. This study offers a novel perspective and foundation for the further exploration of the rules governing the quality of plant materials.

The Effect of Illumination Patterns during Mung Bean Seed Germination on the Metabolite Composition of the Sprouts

Mung bean (Vigna radiata (L.) Wilczek) sprouts are popular over the world because of their taste, nutritional value, well-balanced biochemical composition, and other properties beneficial for human health. Germination conditions affect the composition of metabolites in mung bean sprouts, so a detailed study into its variability is required. This article presents the results of a comparison of the metabolite composition in the leaves of mung bean sprouts germinated first in the dark (DS) and then in the light (LS). Gas chromatography with mass spectrometry (GC-MS) made it possible to identify more than 100 compounds representing various groups of phytochemicals. Alcohols, amino acids, and saccharides predominated in the total amount of compounds. The analysis of metabolomic profiles exposed a fairly high intra- and intervarietal variability in the metabolite content. DS and LS differed in the qualitative and quantitative content of the identified compounds. The intravarietal variability was more pronounced in DS than in LS. DS demonstrated higher levels of saccharides, fatty acids, acylglycerols, and phenolic compounds, while amino acids were higher in LS. Changes were recorded in the quantitative content of metabolites participating in the response of plants to stressors-ornithine, proline, GABA, inositol derivatives, etc. The changes were probably induced by the stress experienced by the sprouts when they were transferred from shade to light. The analysis of variance and principal factor analysis showed the statistically significant effect of germination conditions on the content of individual compounds in leaves. The identified features of metabolite variability in mung bean genotypes grown under different conditions will contribute to more accurate selection of an illumination pattern to obtain sprouts with desirable biochemical compositions for use in various diets and products with high nutritional value.

Multi-Omic Analysis Reveals the Molecular Mechanism of UV-B Stress Resistance in Acetylated RcMYB44 in Rhododendron chrysanthum

Ultraviolet-B (UV-B) radiation is a significant environmental factor influencing the growth and development of plants. MYBs play an essential role in the processes of plant responses to abiotic stresses. In the last few years, the development of transcriptome and acetylated proteome technologies have resulted in further and more reliable data for understanding the UV-B response mechanism in plants. In this research, the transcriptome and acetylated proteome were used to analyze Rhododendron chrysanthum Pall. (R. chrysanthum) leaves under UV-B stress. In total, 2348 differentially expressed genes (DEGs) and 685 differentially expressed acetylated proteins (DAPs) were found. The transcriptome analysis revealed 232 MYB TFs; we analyzed the transcriptome together with the acetylated proteome, and screened 4 MYB TFs. Among them, only RcMYB44 had a complete MYB structural domain. To investigate the role of RcMYB44 under UV-B stress, a homology tree was constructed between RcMYB44 and Arabidopsis MYBs, and it was determined that RcMYB44 shares the same function with ATMYB44. We further constructed the hormone signaling pathway involved in RcMYB44, revealing the molecular mechanism of resistance to UV-B stress in R. chrysanthum. Finally, by comparing the transcriptome and the proteome, it was found that the expression levels of proteins and genes were inconsistent, which is related to post-translational modifications of proteins. In conclusion, RcMYB44 of R. chrysanthum is involved in mediating the growth hormone, salicylic acid, jasmonic acid, and abscisic acid signaling pathways to resist UV-B stress.

Red and blue light-specific metabolic changes in soybean seedlings

Red and blue artificial light sources are commonly used as photosynthetic lighting in smart farm facilities, and they can affect the metabolisms of various primary and secondary metabolites. Although the soybean plant contains major flavonoids such as isoflavone and flavonol, using light factors to produce specific flavonoids from this plant remains difficult because the regulation of light-responded flavonoids is poorly understood. In this study, metabolic profiling of soybean seedlings in response to red and blue lights was evaluated, and the isoflavone-flavonol regulatory mechanism under different light irradiation periods was elucidated. Profiling of metabolites, including flavonoids, phenolic acids, amino acids, organic acids, free sugars, alcohol sugars, and sugar acids, revealed that specific flavonol, isoflavone, and phenolic acid showed irradiation time-dependent accumulation. Therefore, the metabolic gene expression level and accumulation of isoflavone and flavonol were further investigated. The light irradiation period regulated kaempferol glycoside, the predominant flavonol in soybeans, with longer light irradiation resulting in higher kaempferol glycoside content, regardless of photosynthetic lights. Notably, blue light stimulated kaempferol-3-O-(2,6-dirhamnosyl)-galactoside accumulation more than red light. Meanwhile, isoflavones were controlled differently based on isoflavone types. Malonyl daidzin and malonyl genistin, the predominant isoflavones in soybeans, were significantly increased by short-term red light irradiation (12 and 36 h) with higher expressions of flavonoid biosynthetic genes, which contributed to the increased total isoflavone level. Although most isoflavones increased in response to red and blue lights, daidzein increased in response only to red light. In addition, prolonged red light irradiation downregulated the accumulation of glycitin types, suggesting that isoflavone's structural specificity results in different accumulation in response to light. Overall, these findings suggest that the application of specific wavelength and irradiation periods of light factors enables the regulation and acquisition of specialized metabolites from soybean seedlings.

Enhanced UV-B Radiation Induced the Proanthocyanidins Accumulation in Red Rice Grain of Traditional Rice Cultivars and Increased Antioxidant Capacity in Aging Mice

Proanthocyanidins are major UV-absorbing compounds. To clarify the effect of enhanced UV-B radiation on the proanthocyanidin synthesis and antioxidant capacity of traditional rice varieties in Yuanyang terraced fields, we studied the effects of enhanced UV-B radiation (0, 2.5, 5.0, 7.5 kJ·m^-2·d^-1) on the rice grain morphology, proanthocyanidins content, and synthesis. The effects of UV-B radiation on the antioxidant capacity of rice were evaluated by feeding aging model mice. The results showed that UV-B radiation significantly affected the grain morphology of red rice and increased the compactness of starch grains in the starch storage cells of central endosperm. The content of proanthocyanidin B2 and C1 in the grains was significantly increased by 2.5 and 5.0 kJ·m^-2·d^-1 UV-B radiation. The activity of leucoanthocyanidin reductase was higher in rice treated by 5.0 kJ·m^-2·d^-1 than other treatments. The number of neurons in the hippocampus CA1 of mice brain fed red rice increased. After 5.0 kJ·m^-2·d^-1 treatment, red rice has the best antioxidant effect on aging model mice. UV-B radiation induces the synthesis of rice proanthocyanidins B2 and C1, and the antioxidant capacity of rice is related to the content of proanthocyanidins.

Widely targeted metabolomics analysis characterizes the phenolic compounds profiles in mung bean sprouts under sucrose treatment

Phenolic compounds are one of the wholesome substances of mung bean sprouts, showing numerous health-promoting functions. Here, effects of sucrose on phenolic compounds profiles of mung bean sprouts were investigated. Results showed that the content and composition of phenolic compounds were significantly altered by 1‰ and 5‰ sucrose, respectively. The antioxidant capacity was significantly improved by sucrose. Based on metabolomics, 251 metabolites were detected, of which 106 were phenolic compounds. Correlation analysis showed 21 phenolics were positively correlated with antioxidant capacity. The changes in phenolic composition and antioxidant capacity after sucrose treatment were mainly due to the enrichment of phenolic biosynthesis pathways. Moreover, the gene expression and enzyme activity analysis of key phenolic biosynthetic genes contributed to elucidate the phenolic profile under sucrose treatment. In summary, mung bean sprouts are promising sources of dietary phenolic compounds and sucrose treatment is a good process to produce phenolic-rich mung bean sprouts.

Effect of enhanced UV-B radiation on growth and photosynthetic physiology of Iris tectorum maxim

Iris tectorum Maxim. is an important plant that plays a very crucial role in the ecological welfare of wetlands. In this study, the effects of different intensities of UV-B radiation on the growth, photosynthetic pigment content, chlorophyll fluorescence characteristics, chloroplast ultrastructure, and gas exchange parameters of Iris tectorum Maxim. were studied. The results showed that enhanced UV-B radiation had a significant influence on the above-mentioned parameters of iris. Compared with the control, enhanced UV-B radiation caused certain damage to the leaf appearance. With the increasing intensity of radiation, the apparent damage degree became more serious. Enhanced UV-B radiation significantly decreased leaf chlorophyll contents, and the effect accumulated with the exposure time. Enhanced UV-B radiation increased Fo, significantly increased the non-photochemical quenching coefficient NPQ, reduced PSII and Qp, and significantly decreased the Fm, Fv/Fm, and Fv/Fo in leaves. The effect of UV-B radiation on PSII destruction of Iris tectorum Maxim. increased as the radiation intensity increased and the exposure time prolonged. The chloroplast structure was damaged under the enhanced UV-B radiation. More specifically, thylakoid lamellae were distorted, swelling and even blurred, and a large number of starch granules appeared. The effect of the high intensity of radiation on chloroplast ultrastructure was greater than that of lower intensity. Enhanced UV-B radiation reduced significantly the net photosynthetic rate, stomatal conductance, and transpiration rate, and the degree of degradation increased with the increasing irradiation intensity. However, the intercellular CO₂ content increased, which suggests that the main reason for the decrease of photosynthetic rate was the non-stomatal factors.

Appraisal of kinetin spraying strategy to alleviate the harmful effects of UVC stress on tomato plants

Increasing ultraviolet (UV) radiation is causing oxidative stress that accounts for growth and yield losses in the present era of climate change. Plant hormones are useful tools for minimizing UV-induced oxidative stress in plants, but their putative roles in protecting tomato development under UVC remain unknown. Therefore, we investigated the underlying mechanism of pre-and post-kinetin (Kn) treatments on tomato plants under UVC stress. The best dose of Kn was screened in the preliminary experiments, and this dose was tested in further experiments. UVC significantly decreases growth traits, photosynthetic pigments, protein content, and primary metabolites (proteins, carbohydrates, amino acids) but increases oxidative stress biomarkers (lipid peroxidation, lipoxygenase activity, superoxide anion, hydroxyl radical, and hydrogen peroxide) and proline content. Treatment of pre-and post-kinetin spraying to tomato plants decreases UVC-induced oxidative stress by restoring the primary and secondary metabolites' (phenolic compounds, flavonoids, and anthocyanins) status and upregulating the antioxidant defense systems (non-enzymatic antioxidants as ascorbate, reduced glutathione, α-tocopherol as well as enzymatic antioxidants as superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase, glutathione-S-transferase, and phenylalanine ammonia-lyase). Thus, the application of Kn in optimum doses and through different modes can be used to alleviate UVC-induced negative impacts in tomato plants.

UV-B- triggered H2O2 production mediates isoflavones synthesis in germinated soybean

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UV-B up-regulated the activity, gene and protein expression of NADPH oxidase.

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UV-B induced H2O2 signal pathway activation.

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H₂O₂ is an essential signaling molecule mediating UV-B-induced isoflavone production.

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H₂O₂ up-regulated activities, gene and protein expression of PAL, CHS, IFS under UV-B.

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The inhibition of DPI on endogenous H2O2 signal pathway reduced isoflavone synthesis.

In this study, the functions of Hydrogen peroxide (H₂O₂) on the synthesis of isoflavones in germinated soybean under UV-B radiation were investigated. Results showed that the activity, gene, and protein expression of NADPH oxidase were up-regulated by 1.46, 6.92, and 1.34 times with UV-B radiation, while endogenous H₂O₂ content was also significantly increased. UV-B radiation and exogenous H₂O₂ treatment significantly increased the activities, gene and protein expression of phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), and isoflavone synthase (IFS) involved in isoflavones synthesis, and there was a synergistic effect with combining treatment. However, these up-regulation effects were suppressed by the supplementary diphenylene iodonium (DPI), which is the inhibitor of NADPH oxidase. Interestingly, the inhibition effect was largely reversed by exogenous H₂O₂, indicating that H₂O₂ was indispensable in regulating the isoflavones synthesis in germinated soybeans under UV-B radiation. Overall, H₂O₂ is an essential signaling molecule, mediating UV-B-induced isoflavone accumulation.

Health-Promoting Phenolic Compound Accumulation, Antioxidant Response, Endogenous Salicylic Acid Generation, and Biosynthesis Gene Expression in Germinated Pigeon Pea Seeds Treated with UV-B Radiation

Germinated pigeon pea seeds (GPPSs) are good dietary supplements with satisfactory nutritional and medicinal values. In this study, UV-B treatment was used to promote the accumulation of health-promoting phenolic compounds (10 flavonoids and 1 stilbene) in GPPS. The total yield of 11 phenolic compounds (235 839.76 ± 17 118.24 ng/g DW) significantly improved (2.53-fold increase) in GPPSs exposed to UV-B radiation (3 W/m2) for 8 h, whereas free amino acid and reducing sugar contents exhibited a decreasing tendency during UV-B exposure. Meanwhile, the positive response in the antioxidant activities of enzymes and nonenzymatic extracts was noticed in UV-B-treated GPPSs. Moreover, UV-B radiation could cause tissue damages in hypocotyls and cotyledons of the GPPSs and enhance the generation of endogenous salicylic acid, thus activating the expression of biosynthesis genes (especially CHS and STS1). Overall, the simple UV-B supplementation strategy makes GPPSs more attractive as functional foods/nutraceuticals in diet for promoting human health.

Occurrence of isoflavones in soybean sprouts and strategies to enhance their content: A review

Sprouting is a common strategy to enhance the nutritional value of seeds. Here, all the reports regarding the occurrence of isoflavones in soybean sprouts have been covered for the first time. Isoflavones were detected with concentrations ranging from 1 × 10-2 to 1 × 101  g/kg in soybean sprouts. Isoflavone concentration depends on the cultivar, germination time, part of the sprout, light, and temperature. Aglycon isoflavones increased during germination, especially in the hypocotyl, while 6″-O-malonyl-7-O-β-glucoside isoflavones decreased in the hypocotyl and increased in the cotyledon and root. Cooking reduced total isoflavone content. Regarding the strategies to enhance isoflavone contents, fermentation with Aspergillus sojae and external irradiation with UV-A or far-infrared were the methods that caused the greatest increases in aglycon, 7-O-β-glucoside, and total isoflavones. However, the largest increases in 6″-O-malonyl-7-O-β-glucoside and 6″-O-acetyl-7-O-β-glucosides isoflavones were detected after treatment with chitohexaose and calcium chloride, respectively. PRACTICAL APPLICATION: Soybean sprouts are widely consumed and provide essential proteins, antioxidants, and minerals. They are rich in isoflavones, which exhibit numerous health benefits, and have been studied as alternative therapies for a range of hormone-dependent conditions, such as cancer, menopausal symptoms, cardiovascular disease, and osteoporosis. Despite numerous reports being published to date regarding the occurrence of isoflavones in soybean sprouts, the publications in this field are highly dispersed, and a review has not yet been published. This review aims to (1) highlight the particular isoflavones that have been detected in soybean sprouts and their concentrations, (2) compared the effects of temperature, light, cooking and soybean cultivar affect the isoflavone levels on the different parts of the sprout, and (3) discuss the efficacy of the methods to enhance isoflavone contents. This review will provide a better understanding of the current state of this field of research by comparing the general trends and the different treatments for soybean sprouts.

Evolution of Physicochemical Properties, Phenolic Acid Accumulation, and Dough-Making Quality of Whole Wheat Flour During Germination Under UV-B Radiation

The effects of ultraviolet-B (UV-B) radiation on the physiological properties, phenolic acid accumulation, and dough-making quality of wheat during germination were investigated. UV-B radiation inhibited the wheat sprout length and reduced the dry matter loss. As phenolic acids were principally present in the kernels' bran, UV-B radiation could promote their accumulation in the interior of germinated wheat (GW). The total phenolic compounds, ascorbic acid, and antioxidant activity were also enhanced significantly during germination with UV-B. UV-B improved the development time, stability time, rheological properties, and viscosity of GW, and inhibited the α-amylase activity, the destruction of the amorphous region of starch particles, and the proteins degradation process during germination, and thus the deterioration of dough-making quality caused by germination was inhibited. Therefore, UV-B radiation could be a potential approach to enhance the nutritional and dough-making quality of germinated whole wheat flour.

Melatonin mediates isoflavone accumulation in germinated soybeans (Glycine max L.) under ultraviolet-B stress

Soybean germination under ultraviolet-B (UV-B) radiation stress is a common and effective way to enrich the isoflavone content of sprouts. However, the growth and biomass of germinated soybeans are significantly suppressed using this method. Melatonin (MT), a novel plant biostimulant, not only plays a vital protective role in responses to various abiotic stresses but also regulates the accumulation of secondary metabolites. In the present study, the effects of exogenous MT on the growth and isoflavone metabolism of germinating soybeans exposed to UV-B stress were investigated. Compared to UV-B stress, the application of exogenous MT (25 μM) significantly increased sprout length, fresh weight, Ca2+ influx, and peroxidase activity; markedly decreased the content of malondialdehyde and H2O2 and the fluorescence intensity of H2O2 and O2•-; but had no noticeable effect on the activity of superoxide dismutase and catalase during germination. Moreover, the content of total flavonoids and isoflavone monomers (including daidzein, genistein, daidzin, glycitin and genistin) in 4-day-old germinated soybeans was significantly enhanced by MT application under UV-B stress and was not only companied by dramatically increased phenylalanine ammonia lyase activity, but also by markedly increased relative expression levels of phenylalanine ammonia lyase1, chalcone synthase, isoflavone reductase and flavanone 3-hydroxylase that are involved in the isoflavone biosynthesis pathway. The inhibitory effects of UV-B stress on the growth and biomass of germinated soybeans were alleviated with exogenous MT. MT enhanced the content of total flavonoids and isoflavone monomers under UV-B stress by increasing the activity and relative gene expression level of critical isoflavone biosynthesis-related enzymes.

Red light enhances folate accumulation in wheat seedlings

Red, white, blue, green, and yellow lights were applied to investigate their effects on folate accumulation in wheat seedlings. The different lights, especially red light, significantly increased the total folate content. Total folate showed maximum accumulation under 30 μmol/(m²·s) of red light, with an increase of 24% compared with the control (darkness). 5-Methyl-tetrahydrofolate (5-CH₃-THF) was the dominant folate component, and was significantly increased by red light irradiation. In addition, under red light, the folate content of leaves was higher and more sensitive to light than that of endosperm or roots. Red light up-regulated the expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GCH1) and aminodeoxychorismate synthase(ADCS), enhanced the activity of GCH1 and ADCS, and increased the content of precursors of folate synthesis, including pterin and p-aminobenzoic acid (pABA). Hence, the increased folate accumulation promoted by light could be attributed to the increased content of folate synthesis precursors, the activity of key enzymes, and related gene expression.

Metabolomic analysis reveals dose-dependent alteration of maize (Zea mays L.) metabolites and mineral nutrient profiles upon exposure to zerovalent iron nanoparticles

Nanoscale zero-valent iron (nZVI) has been widely applied in the environmental field to degrade organic pollutants. The potential risk posed from nZVI on crop species is not well understood and is critical for sustainable application in the future. In this study, maize (Zea mays L.) plants were cultivated in field soils mixed with nZVI at 0, 50, and 500 mg/kg soil for four weeks. Upon exposure to 500 mg/kg nZVI, ICP-MS results showed that Fe accumulated by roots and translocated to leaves was increased by 36% relative to untreated controls. At 50 mg/kg, root elongation was enhanced by 150-200%; at 500 mg/kg, pigments, lipid peroxidation, and polyphenolic levels in leaves were increased by 12, 87 and 23%, respectively, whereas the accumulation of Al, Ca, and P were decreased by 62.2%, 19.7%, and 13.3%, respectively. A gas chromatography-mass spectrometry (GC-MS) based metabolomics analysis of maize roots revealed that antioxidants and stress signaling-associated metabolites were downregulated at 50 mg/kg, but were upregulated at 500 mg/kg. At 50 mg/kg, the content of glutamate was increased by 11-fold, whereas glutamine was decreased by 99% with respect to controls. Interestingly, eight metabolic pathways were disturbed at 50 mg/kg, but none at 500 mg/kg. This metabolic reprogramming at the lower dose represented potential risks to the health of exposed plants, which could be particularly important although no phenotypic impacts were noted. Overall, metabolites analysis provides a deeper understanding at the molecular level of plant response to nZVI and is a powerful tool for full characterization of risk posed to crop species as part of food safety assessment.

Effects of UV-A radiation on organ-specific accumulation and gene expression of isoflavones and flavonols in soybean sprout

Organ-specific flavonoid destination in soybean sprouts following UV irradiation is still unclear although the metabolic pathway of flavonoid synthesis and UV responded flavonoid accumulation have been well investigated. We report the identification of organ-specific localization and specific gene expression of isoflavones and kaempferol glycosides in the soybean sprouts responded to UV-A irradiation. UV-A irradiation stimulated only root isoflavones, especially increase of genistein types. The daidzein types predominated in non-UV-A treated roots. Kaempferol glycosides were not increased in roots by UV-A, but distinctly increased in aerial organs, especially in the cotyledons. These results demonstrate that UV-A upregulates the naringenin pathway synthesizing genistin and kaempferol rather than the liquiritigenin pathway synthesizing daidzin and glycitin. High GmUGT9 and other gene expression related to isoflavone synthesis in roots clearly demonstrate the UV-A-induced isoflavone accumulation. Aerial organ specific increase of GmF3H, GmFLS1, and GmDFR1 expression by UV-A distinctly demonstrates the flavonol increase in aerial organs.

Gene Analysis of Genetically Modified Soybean Lectin Based on Fluorescence Quantitative PCR

Considering that the genetically modified soybean lectin gene is affected by the gene type, to improve the stability of the genetically modified soybean lectin gene, a method based on fluorescence quantitative PCR to analyze the genetic characteristics of the genetically modified soybean lectin was proposed. The common soybean varieties, Wangshuibai and Huangdou No. 3 were selected as materials for tissue-specific expression analysis. Under the background conditions of analyzing the genetically modified soybean lectin genes, fluorescent quantitative PCR was applied to the analysis of genetic characteristics. The characteristics of the genetically modified soybean lectin gene were analyzed in terms of location characteristics and expression characteristics. The results showed that the soybean lectin gene has a complex functional mechanism and may participate in a variety of stress-related regulatory or signal transduction pathways in different ways; Lectin2.1 transcripts are expressed in abundance in glume and lemma in seedling tips, Lectin2.2 was mainly expressed in the roots, and a small amount was expressed in leaves and lemma; Lectin2.1 and Lectin2.2 are highly similar in nucleic acid and amino acid composition, and have similar subcellular localization characteristics.

Comparation of the phytotoxicity between chemically and green synthesized silver nanoparticles

Green synthesis of silver nanoparticles (Ag NPs) by using plants extracts has provided an eco-friendly alternation for industry and agriculture application. Here, we prepared Ag NPs by using the cucumber leaves and rice husk extracts, and further assessed the antimicrobial activity and phytotoxicity of green synthesized Ag NPs (g-Ag NPs) comparing with chemically synthesized Ag NPs (chem-Ag NPs). The chem-Ag NPs had strong antibacterial activity on the growth of Escherichia coli, while g-Ag NPs by rice husks (gr-Ag NPs) exhibited long-term antibacterial effects. In terms of phytotoxicity, the chem-Ag NPs induced over-generation of ROS and activated plant antioxidant defense systems, thus resulting in the upregulation of MDA and Zn contents and downregulation of antioxidant capacity, carotenoid, globulin and Mo contents. However, g-Ag NPs significantly promoted cucumber photosynthesis by increasing chlorophyll contents. Besides, the green synthesized Ag NPs by cucumber extracts (gc-Ag NPs) increased protein contents and gr-Ag NPs stimulated the upregulation of Mn and the downregulation of Al, which were all positive effects. Overall, compared with chem-Ag NPs, g-Ag NPs exhibited long-tern antimicrobial properties and attenuated toxicity to plants, which could be used as potential nanopesticide or nanoscale growth regulator in agriculture.

Nitroso-hemoglobin-ginger conjugates effects on bacterial growth and color stability in a minced beef model

This study aims to enhance the color and microbiological qualities of a raw beef using natural ingredients. Nitroso-hemoglobin (NO-Hb) integrated with vitamin C (VC), calcium lactate, and ginger complexation were used as natural inhibitors against the growth of aerobic and pathogenic bacteria, namely (Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Salmonella. NO-Hb inhibited E. coli, S. aureus, and Salmonella, and enhanced the color stability more than nitrite in the minced beef model. After the multiexponential analysis of relaxation decays, the water component (T2b) was analyzed using the low-field NMR. The results indicated that, at the 7th d of cold-storage the third component (T2) was detected. Significant correlations were observed between T21 and T22 relaxation times and water-holding capacity in minced beef, implying that the LF-NMR measurements could be an efficient method for the determination and prediction of beef freshness. NO-Hb- ginger mixture, as a novel ingredient, could be used instead of nitrite in terms of meat safety.

Light and Low Relative Humidity Increase Antioxidants Content in Mung Bean (Vigna radiata L.) Sprouts

In the last decades, there has been a growing interest in the production of sprouts, since they are a highly nutritious food, particularly suitable for indoor farming in urban areas. Achieving sprout production in indoor systems requires an understanding of possible alterations induced by the microclimate. The aim of this study was to analyze the combined effect of presence/absence of light and high/low air relative humidity (RH) on mung bean sprouts. Morpho-anatomical development and functional anatomical traits in hypocotyl were quantified. The content of antioxidants, soluble sugars, and starch were measured for nutritional and functional purposes. Different RH regimes mainly induced morpho-anatomical modifications, while the presence/absence of light changed the content of antioxidant compounds. Increments in stele diameter at high RH suggest a higher water uptake and conductivity, compared to the low RH treatment; low RH and light induced anatomical traits improving plant water transport (reduced number of cortical layers) and increased the production of antioxidants. The overall results suggested that RH and light, already at the early stages of development, affect the plant's nutritional value. Therefore, the combination of light and low RH allows the production of antioxidant-rich mung bean sprouts to be used as a food supplement.

Physiological and metabolic responses of maize (Zea mays) plants to Fe3O4 nanoparticles

Fe₃O₄ nanoparticles (NPs), as representative magnetic materials, have been widely used in the industrial and biomedical sectors, and their environmental impacts must be evaluated for their sustainable use. In this study, the interactions between Fe₃O₄ NPs and maize plants were investigated by a combination of phenotypic and metabolic approaches. Maize plants (Zea mays) were grown in soil treated with Fe₃O₄ NPs at 0, 50 and 500 mg/kg for 4 weeks. Fe₃O₄ NPs had no impact on plant biomass or photosynthesis. However, root length of maize plant significantly increased, with decreased malondialdehyde (MDA) level, indicating the positive effects on root development and membrane integrity. Inductively coupled plasma optical emission spectrometry (ICP-OES) revealed that Fe₃O₄ NPs resulted in a significant Fe accumulation in roots, instead of leaves. In addition, 500 mg/kg Fe₃O₄ NPs significantly promoted dehydrogenase enzyme activity by 84.9%. Metabolomics revealed that maize root metabolomes were re-programmed by Fe₃O₄ NPs exposure. Metabolic pathways associated with antioxidant and defence were inactivated by Fe₃O₄ NPs, indicating the protective role of Fe₃O₄ NPs for microbes and plant roots. Taken together, the results indicate a limited impact of environmental Fe₃O₄ NPs on plant growth. Taken together, the results of this study offer new insights into the molecular mechanisms by which maize responds to Fe₃O₄ NP exposure.

Effect of germination environment on the biochemical compounds and anti-inflammatory properties of soybean cultivars

In this study, we investigated changes in the isoflavone content, total phenolic content (TPC), total flavonoid content (TFC), antioxidant activities (DPPH, ABTS), and anti-inflammatory activities of small-seeded and large-seeded soybean cultivars during germination (light/dark conditions). Total isoflavone content was higher at the seed stage in large-seeded soybeans, while it increased after 7 days of germination in small-seeded soybeans, particularly in response to light conditions, under which they had high TPC, TFC, and antioxidant activities. In large-seeded soybeans, the germination environment did not significantly affect TFC or DPPH inhibition, whereas TPC and ABTS inhibition were high under dark germination conditions. Extracts of sprouts exhibited superior anti-inflammatory activities. Nitric oxide production was slightly lower in small-seeded and large-seeded soybeans germinated under light and dark conditions, respectively. Our findings indicate that germinated soybeans improved nutritionally, and that enhancement of bioactivity under different germination environments could contribute to the selection of appropriate soybean cultivars.

Isoflavone accumulation and the metabolic gene expression in response to persistent UV-B irradiation in soybean sprouts

This study investigated the effects of persistent ultraviolet B (UV-B) irradiation on isoflavone accumulation in soybean sprouts. Three malonyl isoflavones were increased by UV-B. Malonylgenistin specifically accumulated upon UV-B exposure, whereas the other isoflavones were significantly increased under both dark conditions and UV-B exposure. The results of isoflavone accumulation to UV-B irradiation time were observed as following: acetyl glycitin rapidly increased and then gradually decreased; malonyl daidzin and malonyl genistin were highly accumulated within an intermediate period; genistein and daidzin were gradually maximized; daidzin, glycitin, genistein, and malonyl glycitin did not increase; and glycitin, acetyl daidzin, and acetyl genistin exhibited trace amounts. Transcriptional analysis of isoflavonoid biosynthetic genes demonstrated that most metabolic genes were highly activated in response to UV-B 24 and UV-B 36 treatments. In particular, it was found that GmCHS6, GmCHS7, and GmCHS8 genes among the eight known genes encoding chalcone synthase were specifically related to UV-B response.

Comparative Analysis of Phenolic Compound Profiles, Antioxidant Capacities, and Expressions of Phenolic Biosynthesis-Related Genes in Soybean Microgreens Grown under Different Light Spectra

Light-emitting diode (LED) based light sources, which can selectively and quantitatively provide different spectra, have been frequently applied to manipulate plant growth and development. In this study, the effects of different LED light spectra on the growth, phenolic compounds profile, antioxidant capacity, and transcriptional changes in genes regulating phenolic biosynthesis in soybean microgreens were investigated. The results showed that light illumination decreased the seedling length and yield but increased phenolic compound content. Blue light and ultraviolet-A (UV-A) induced significant increases in total phenolic and total flavonoid content, as compared with the white light control. Sixty-six phenolic compounds were identified in the soybean samples, of which isoflavone, phenolic acid, and flavonol were the main components. Ten phenolic compounds obtained from the orthogonal partial least-squares discriminant analysis (OPLS-DA) were reflecting the effect of light spectra. The antioxidant capacity was consistent with the phenolic metabolite levels, which showed higher levels under blue light and UV-A compared with the control. The highest transcript levels of phenolic biosynthesis-related genes were observed under blue light and UV-A. The transcript levels of GmCHI, GmFLS, and GmIOMT were also upregulated under far-red and red light. Taken together, our findings suggested that the application of LED light could pave a green and effective way to produce phenolic compound-enriched soybean microgreens with high nutritional quality, which could stimulate further investigations for improving plant nutritional value and should have a wide impact on maintaining human health.

Lower levels of UV-B light trigger the adaptive responses by inducing plant antioxidant metabolism and flavonoid biosynthesis in Medicago sativa seedlings

Ultraviolet-B (UV-B) light, as an intrinsic part of sunlight, has more significant effects on plant growth and photomorphogenesis than other organisms due to plant's sessile growth pattern. In our studies, we have observed that alfalfa (Medicago sativa L.) seedlings are very sensitive to UV-B performance. Seedlings have grown better at lower levels of UV-B light (UV-B irradiation dosage <17.35 μW cm-2 day-1), and have higher UV-resistance. However, the higher levels of UV-B light (UV-B irradiation dosage >17.35 μW cm-2 day-1) has caused severe stress injuries to alfalfa seedlings, and seriously inhibited its growth and development. Chlorophyll biosynthesis and chlorophyll fluorescence have been suppressed under all different dosage of UV-B light conditions. Plant antioxidant enzymes were induced by lower levels of UV-B, but greatly inhibited under higher levels of UV-B light. The contents of flavonoid compounds significantly increased under UV-B light compared with controls, and that was more significant under lower levels of UV-B than higher levels of UV-B. Therefore, we have assumed that the significant induction of plant antioxidant capacity and flavonoid excessive accumulation play a central role in alfalfa UV-B tolerance to lower levels of UV-B irradiation.

Induction of isoflavonoid biosynthesis in Lotus japonicus after UV-B irradiation

Enhanced ultraviolet radiation (UV) is an important environmental factor that may cause reductions in the growth and productivity of plants. In the present work we studied the response to UV-B radiation in leaves of the model legume Lotus japonicus. After UV-B treatment, induction of phenyalanine-ammonia lyase gene expression and enzyme activity was detected. Among the ten genes encoding for PAL found in the L. japonicus genome, LjPAL1 was both the most expressed and the most induced. All the genes encoding for enzymes of the isoflavonoid pathway were also strongly induced; this was paralleled by a marked accumulation of vestitol and isoliquiritigenin. Moreover, accumulation of several other isoflavonoids was also detected. In vitro measurements of the free radical scavenging capacity of vestitol indicated that this compound can be an appropriate free radical scavenger, suggesting a possible role for this molecule in the response to abiotic stress. On the other hand, an increase of flavonol levels was not observed while the expression of the key enzymes for flavonol biosynthesis flavanone-3-hydroxylase and flavonol synthase was decreased. Taken together, these results indicate that L. japonicus follows a peculiar strategy in its response to UV radiation by accumulating isoflavonoids as an possible alternative to accumulation of flavonols as observed in other plant species.

Chloroplast proteomic analysis of Triticum aestivum L. seedlings responses to low levels of UV-B stress reveals novel molecular mechanism associated with UV-B tolerance

In this study, we have investigated UV-B-induced alterations including chloroplast ultrastructure, chlorophyll fluorescence parameters, physiological metabolism, and chloroplast proteome profile. Comparison of seedling phenotypic characterization and physiological status revealed that the low level of 1.08 KJ m^-2 of UV-B irradiation had no obvious effects on seedling phenotype and growth and maintained better chloroplast ultrastructure and higher photosynthetic efficiency. Nevertheless, the high dose of 12.6 KJ m^-2 of UV-B stress caused significant inhibitory effects on the growth and development of wheat seedlings. Proteomic analysis of chloroplasts with or without 1.08 KJ m^-2 of UV-B irradiation identified 50 differentially expressed protein spots, of which 35 were further analyzed by MALDI-TOF/TOF mass spectrometry. These proteins were found to be involved in multiple cellular metabolic processes including ATP synthesis, light reaction, Calvin cycle, detoxifying and antioxidant reactions, protein metabolism, malate and tetrapyrrole biosynthesis, and signal transduction pathway. We also identified 3 novel UV-B-responsive proteins, spots 8801, 8802, and 9201, and predicted three new proteins might be UV-B protective proteins. Our results imply chloroplasts play a central protective role in UV-B resistance of wheat seedlings and also provide novel evidences that UV-B stress directly affects on the structure and function of chloroplasts and explore molecular mechanisms associated with plant UV-B tolerance from chloroplast perspective.

UV-B mediates isoflavone accumulation and oxidative-antioxidant system responses in germinating soybean

This study investigated the relationships among UV-B radiation dose, isoflavone monomers and the oxidative-antioxidant system in germinating soybean. Results showed that the isoflavone monomers content showed a good fit to the quadratic model with UV-B radiation dose, except for aglycones. UV-B decreased phenylalanine content and up-regulated the key enzymes activities in isoflavone biosynthesis. H2O2, electrolyte leakage, malondialdehyde, T22 and M22 were increased, while T23 and M23 decreased. Microscopic analysis showed excess UV-B radiation resulted in the reduced cell volume, irregular cell shape, and increased cell space. The antioxidant enzymes activities were enhanced by UV-B. These results demonstrated that UV-B could trigger the formation of H2O2, resulting in the oxidative stress. Thus, the antioxidant system, including the enzymatic (enhanced the antioxidant enzymes activities) and nonenzymatic (accumulated isoflavones) were activated to minimize oxidative damage. This study provides theoretical basis for enhancing isoflavone monomer accumulation in plant-source foods by UV-B.

Single particle ICP-MS and GC-MS provide a new insight into the formation mechanisms during the green synthesis of AgNPs

For the first time, the formation kinetics and responsible metabolites during the green synthesis of AgNPs were elucidated by sp-ICP-MS and GC-MS.

Soybean leaves transcriptomic data dissects the phenylpropanoid pathway genes as a defence response against Phakopsora pachyrhizi

Asian soybean rust (ASR), caused by the obligate biotrophic fungus Phakopsora pachyrhizi, is responsible for severe yield losses of up to 90% in all soybean producing countries. Till today, eight resistance to Phakopsora pachyrhizi (Rpp) loci have been mapped in soybean. Their resistance mechanism is race specific but largely unknown. The transcriptomes of susceptible BRS184 and Rpp3 with ASR isolates T1-2 at 24 h after inoculation (hai) and without ASR inoculation (mock) were annotated by similarity searching with different databases. A total of 4518 differentially expressed genes were identified. We found 70.89%, 56.61%, 32.13%, and 56.04% genes in the protein family databases (PFAM), Gene Ontology (GO), Eukaryotic clusters of Orthologous Groups (KOG), and Kyoto Encyclopedia of Genes and Genomes Pathway (KEGG), respectively. KEGG disclosed that 52% of the phenylpropanoid pathway related genes were up-regulated. The relative gene expression study for selected genes of that pathway was conducted by RT-qPCR using Rpp1-Rpp4 carrying lines with T1-2 infection. The RT-qPCR results revealed that the Rpp lines utilized these genes in a rate limiting manner as a defence response. With the exception of glycinol 4-dimethylallyltransferase (G4DT) and chalcone reductase (CHR), all the genes showed the greatest expression at 12 hai, but the gene expressions which occur between 24 and 96 hai make these Rpp lines unique to their respective ASR isolates. Moreover, functional coordination of arogenate dehydratase 6 (ADT6) and 4-hydroxy-3-methylbut-2-enyl diphosphate synthase (ispG), chalcone synthase (CHS) and CHR, and G4DT and phytyltransferase 3 (PT3) may have a great impact on soybean resistance against ASR.