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Keywords = ASA–GSH cycle

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21 pages, 2600 KB  
Article
Bamboo Biochar and Sodium Silicate Alleviate Oxybenzone-Induced Phytotoxicity via Distinct Mechanisms for Sustainable Plant Protection
by Chuantong Cui, Wenhai Yang, Weiru Dang, Ruiya Chen, Pedro García-Caparrós, Guoqun Yang, Jianhua Huang and Li-Jun Huang
Plants 2025, 14(15), 2382; https://doi.org/10.3390/plants14152382 - 2 Aug 2025
Viewed by 2813
Abstract
Oxybenzone (OBZ), an organic ultraviolet filter, is an emerging contaminant posing severe threats to ecosystem health. Using tobacco (Nicotiana tabacum) as a model plant, this study investigated the alleviation mechanisms of exogenous silicon (Na2SiO3, Si) and bamboo-based [...] Read more.
Oxybenzone (OBZ), an organic ultraviolet filter, is an emerging contaminant posing severe threats to ecosystem health. Using tobacco (Nicotiana tabacum) as a model plant, this study investigated the alleviation mechanisms of exogenous silicon (Na2SiO3, Si) and bamboo-based biochar (Bc) under OBZ stress. We systematically analyzed physiological and biochemical responses, including phenotypic parameters, reactive oxygen species metabolism, photosynthetic function, chlorophyll synthesis, and endogenous hormone levels. Results reveal that OBZ significantly inhibited tobacco growth and triggered a reactive oxygen species (ROS) burst. Additionally, OBZ disrupted antioxidant enzyme activities and hormonal balance. Exogenous Bc mitigated OBZ toxicity by adsorbing OBZ, directly scavenging ROS, and restoring the ascorbate-glutathione (AsA-GSH) cycle, thereby enhancing photosynthetic efficiency, while Si alleviated stress via cell wall silicification, preferential regulation of root development and hormonal signaling, and repair of chlorophyll biosynthesis precursor metabolism and PSII function. The mechanisms of the two stress mitigators were complementary, Bc primarily relied on physical adsorption and ROS scavenging, whereas Si emphasized metabolic regulation and structural reinforcement. These findings provide practical strategies for simultaneously mitigating organic UV filter pollution and enhancing plant resilience in contaminated soils. Full article
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28 pages, 7191 KB  
Article
Selenium Alleviates Cadmium Toxicity by Regulating Carbon Metabolism, AsA-GSH Cycle, and Cadmium Transport in Glycyrrhiza uralensis Fisch. Seedlings
by Xuerong Zheng, Jiafen Luo, Xin Li, Chaoyue Zhang, Guigui Wan, Caixia Xia and Jiahui Lu
Plants 2025, 14(12), 1736; https://doi.org/10.3390/plants14121736 - 6 Jun 2025
Viewed by 910
Abstract
Cadmium (Cd) accumulation in plants hinders their growth and development while posing significant risks to human health through food chain transmission. Glycyrrhiza uralensis Fisch. (G. uralensis) is a medicinal plant valued for its roots and plays a crucial role in harmonizing [...] Read more.
Cadmium (Cd) accumulation in plants hinders their growth and development while posing significant risks to human health through food chain transmission. Glycyrrhiza uralensis Fisch. (G. uralensis) is a medicinal plant valued for its roots and plays a crucial role in harmonizing various herbs in traditional Chinese medicine prescriptions. However, widespread Cd contamination in soil limits safe cultivation and application. Selenium (Se), a beneficial element in plants, can regulate plant growth by enhancing carbon metabolism and reducing heavy metal uptake. This study aimed to elucidate the protective mechanisms of Se application in licorice plants exposed to 20 μM Cd. Experiments with 1 and 5 μM of Se revealed that 1 μM of Se provided the best protective effects. This concentration reduced the Cd2+ content in the roots of G. uralensis, while significantly increasing plant biomass, root length, SPAD value, and contents of K+, Ca2+, and S2−. Additionally, the treatment reduced the malondialdehyde (MDA) content by 30.71% and 58.91% at 12 h and 30 d, respectively. The transcriptome analysis results suggest that Se mitigated Cd toxicity by enhancing carbon metabolism, regulating the AsA-GSH cycle, reducing Cd absorption, promoting Cd transport and compartmentalization, and modulating Cd resistance-associated transcription factors. These findings clarify the mechanisms by which Se alleviates Cd toxicity in G. uralensis and offer a promising strategy for the safe cultivation and quality control of medicinal herbs in Cd-contaminated soils. Full article
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20 pages, 2275 KB  
Article
The Regulatory Role of Exogenous Carnitine Applications in Lipid Metabolism, Mitochondrial Respiration, and Germination in Maize Seeds (Zea mays L.)
by Hulya Turk, Mucip Genisel and Rahmi Dumlupinar
Life 2025, 15(4), 631; https://doi.org/10.3390/life15040631 - 9 Apr 2025
Viewed by 794
Abstract
The present study aimed to investigate the effects of exogenous carnitine treatments on maize seed germination by stimulating lipid metabolism and regulating the mitochondrial respiratory pathway. Maize seeds were grown as control, 5, 7.5, and 10 μM carnitine treatment groups in a germination [...] Read more.
The present study aimed to investigate the effects of exogenous carnitine treatments on maize seed germination by stimulating lipid metabolism and regulating the mitochondrial respiratory pathway. Maize seeds were grown as control, 5, 7.5, and 10 μM carnitine treatment groups in a germination chamber at 25 °C under dark conditions for 5 d. It was determined that carnitine treatments increased the germination rate (GR), germination index (GI), germination potential (GP), vigor index (VI), root and hypocotyl length, fresh weight (FW), and content of total soluble protein but decreased the total carbohydrate content. It was also found that it increased the activities of α-amylase, isocitrate lyase (ICL), and malate synthase (MS) enzymes, which are critical in the germination process, and upregulated the expression of ICL and MS genes. To clarify the potential of carnitine treatments to promote the participation of lipids in respiration in roots and hypocotyls, lipase, carnitine acyltransferases (CATI and CATII), and citrate synthase (CS) enzyme activities were examined, and significant increases in these activities were detected. It was also found that gene levels of respiratory enzymes cytochrome oxidase (COX), pyruvate dehydrogenase (PDH), and Atp synthase, lipase, and CS proteins were upregulated by carnitine treatment. In support of the enzyme and gene change findings, significant changes were determined in fatty acid contents, free carnitine, and long-chain acylcarnitine levels in seeds, roots, and hypocotyls depending on carnitine application. In roots and hypocotyls, carnitine treatments significantly increased glutamine synthase (GS) and glutamate dehydrogenase (NADH-GDH) activities and gene expression levels, which are closely related to the tricarboxylic acid cycle (TCA). It was also noted that all proteins analyzed at the gene expression level were upregulated by carnitine applications in seeds. In addition, significant increases were recorded in antioxidant enzyme ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities and total ascorbate (AsA) and glutathione (GSH) contents in roots and hypocotyls, while decreases were determined in guaiacol peroxidase (GPX) and catalase activities. Significant changes were recorded in all parameters examined, especially with 7.5 µM carnitine application. The findings suggest that carnitine may promote the transport of fatty acids to mitochondrial respiration by accelerating lipid catabolism in five-day-old maize and contribute to seed germination and growth and development processes by activating other metabolic pathways associated with respiration in this process. Full article
(This article belongs to the Section Plant Science)
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21 pages, 3555 KB  
Article
Physiological and Transcriptomic Analysis of Two Types of Hami Melons in Low-Temperature Storage
by Wanqin Liao, Linlu Xiao, Xiangshuai Hao, Chunhui Shan, Zhongkai Zhou, Ming Ning and Fengxian Tang
Plants 2025, 14(8), 1153; https://doi.org/10.3390/plants14081153 - 8 Apr 2025
Viewed by 758
Abstract
The Hami melon is a characteristic economic crop in Xinjiang. Long-term storage at low temperatures can cause cold damage and significantly impact the storage quality of Hami melon fruits. This study investigated the cold resistance of two Hami melon varieties under low temperatures, [...] Read more.
The Hami melon is a characteristic economic crop in Xinjiang. Long-term storage at low temperatures can cause cold damage and significantly impact the storage quality of Hami melon fruits. This study investigated the cold resistance of two Hami melon varieties under low temperatures, screened key genes, and further explored their resistance mechanisms. By comparing and analyzing the relationship between phenotypic morphology, physiological indicators, and storage time, it was found that the symptoms of cold damage in Hami melons are related to both storage time and variety. To analyze the response mechanisms of Hami melons to cold stress at the molecular level, we conducted transcriptome sequencing analysis on the cold-sensitive Hami melon variety Gold Queen and the cold-resistant variety Jia Shi. The analysis shows that cold stress induces the expression of these differentially expressed genes, which participate in the AsA-GSH cycling system, form the NADPH-P450 pathway, and establish the ERF-WRKY cold resistance pathway. This, in turn, increases the content of free proline in the fruits, clears denatured proteins within the fruit, maintains the stability of the redox system, and inhibits certain differentially expressed genes that regulate cell wall metabolism, thereby alleviating fruit softening and improving cold resistance. Full article
(This article belongs to the Section Plant Physiology and Metabolism)
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17 pages, 2185 KB  
Article
Hydrogen Sulfide Mitigates Manganese-Induced Toxicity in Malus hupehensis Plants by Regulating Osmoregulation, Antioxidant Defense, Mineral Homeostasis, and Glutathione Ascorbate Cycle
by Bowen Liu, Baozhu Wang, Tianlnog Chen and Manrang Zhang
Horticulturae 2025, 11(2), 133; https://doi.org/10.3390/horticulturae11020133 - 26 Jan 2025
Cited by 2 | Viewed by 858
Abstract
Manganese (Mn) is a toxic metal element that adversely affects plant growth. Hydrogen sulfide (H2S) is considered an important signaling molecule with significant potential in alleviating various abiotic stresses. However, there is limited information available on the role of H2 [...] Read more.
Manganese (Mn) is a toxic metal element that adversely affects plant growth. Hydrogen sulfide (H2S) is considered an important signaling molecule with significant potential in alleviating various abiotic stresses. However, there is limited information available on the role of H2S in alleviating manganese stress in plants. In this study, the effects of exogenous H2S and its scavenger, homocysteine thiolactone (HT), on the physiological and biochemical parameters of Malus hupehensis var. pingyiensis seedlings were evaluated. Our results show that H2S treatment significantly alleviates growth inhibition and oxidative damage induced by manganese stress in Malus hupehensis seedlings, primarily by enhancing antioxidant enzyme activity and up-regulating the ascorbate-glutathione (ASA-GSH) cycle. H2S treatment increased photosynthetic pigment content and helped maintain osmotic balance in leaves, thereby enhancing key gas exchange parameters and mitigating manganese-induced suppression of photosynthesis. H2S treatment enhanced the absorption of Ca, Mg, Fe and Zn under manganese stress, significantly reduced manganese accumulation in Malus hupehensis seedlings, and modulated the transcriptional expression of MTPs, facilitating the transfer of manganese to the leaves. Thus, H2S reduces oxidative damage and promotes growth under Mn stress, highlighting its important role in plant stress tolerance. Full article
(This article belongs to the Special Issue Tolerance and Response of Ornamental Plants to Abiotic Stress)
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28 pages, 8594 KB  
Article
Nano-Zinc Oxide Can Enhance the Tolerance of Apple Rootstock M9-T337 Seedlings to Saline Alkali Stress by Initiating a Variety of Physiological and Biochemical Pathways
by Jietao Zhai, Xulin Xian, Zhongxing Zhang and Yanxiu Wang
Plants 2025, 14(2), 233; https://doi.org/10.3390/plants14020233 - 15 Jan 2025
Cited by 6 | Viewed by 1621
Abstract
Soil salinization severely restricts the growth and development of crops globally, especially in the northwest Loess Plateau, where apples constitute a pillar industry. Nanomaterials, leveraging their unique properties, can facilitate the transport of nutrients to crops, thereby enhancing plant growth and development under [...] Read more.
Soil salinization severely restricts the growth and development of crops globally, especially in the northwest Loess Plateau, where apples constitute a pillar industry. Nanomaterials, leveraging their unique properties, can facilitate the transport of nutrients to crops, thereby enhancing plant growth and development under stress conditions. To investigate the effects of nano zinc oxide (ZnO NP) on the growth and physiological characteristics of apple self-rooted rootstock M9-T337 seedlings under saline alkali stress, one-year-old M9-T337 seedlings were used as experimental materials and ZnO NPs were used as donors for pot experiment. Six treatments were set up: CK (normal growth), SA (saline alkali stress,100 mmol/L NaCl + NaHCO3), T1 (saline alkali stress + 50 mg/L ZnO NPs), T2 (saline alkali stress + 100 mg/L ZnO NPs), T3 (saline alkali stress + 150 mg/L ZnO NPs) and T4 (saline alkali stress + 200 mg/L ZnO NPs). The results were found to show that saline alkali stress could significantly inhibit the growth and development of M9-T337 seedlings, reduce photosynthetic characteristics, and cause ion accumulation to trigger osmotic regulation system, endogenous hormone and antioxidant system imbalances. However, the biomass, plant height, stem diameter, total leaf area and leaf perimeter of M9-T337 seedlings were significantly increased after ZnO NP treatment. Specifically speaking, ZnO NPs can improve the photosynthetic capacity of M9-T337 by increasing the content of photosynthetic pigment, regulating photosynthetic intensity and chlorophyll fluorescence parameters. ZnO NPs can balance the osmotic adjustment system by increasing the contents of soluble protein (SP), soluble sugar (SS), proline (Pro) and starch, and can also enhance the activities of enzymatic (SOD, POD, and CAT) and non-enzymatic antioxidant enzymes (APX, AAO, GR, and MDHAR) to enhance the scavenging ability of reactive oxygen species (H2O2, O2•−), ultimately reducing oxidative damage; ZnO NPs promoted the growth of M9-T337 seedlings under saline alkali stress by synergistically responding to auxin (IAA), gibberellin (GA3), zeatin (ZT) and abscisic acid (ABA). Additionally, the Na+/K+ ratio was reduced by upregulating the expression of Na+ transporter genes (MdCAX5, MdCHX15, MdSOS1, and MdALT1) and downregulating the expression of K+ transporter genes (MdSKOR and MdNHX4). After comprehensive analysis of principal components and correlation, T3 (150 mg/L ZnO NPs) treatment possessed the best mitigation effect. In summary, 150 mg/L ZnO NPs(T3) can effectively maintain the hormone balance, osmotic balance and ion balance of plant cells by promoting the photosynthetic capacity of M9-T337 seedlings, and enhance the antioxidant defense mechanism, thereby improving the saline alkaline tolerance of M9-T337 seedlings. Full article
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21 pages, 5403 KB  
Article
Exogenous 2,4-Epibrassinolide Alleviates Alkaline Stress in Cucumber by Modulating Photosynthetic Performance
by Wenjing Nie, Qinghai He, Jinzhao Ma, Hongen Guo and Qinghua Shi
Plants 2025, 14(1), 54; https://doi.org/10.3390/plants14010054 - 27 Dec 2024
Cited by 6 | Viewed by 1170
Abstract
Brassinosteroids (BRs) are recognized for their ability to enhance plant salt tolerance. While considerable research has focused on their effects under neutral salt conditions, the mechanisms through which BRs regulate photosynthesis under alkaline salt stress are less well understood. This study investigates these [...] Read more.
Brassinosteroids (BRs) are recognized for their ability to enhance plant salt tolerance. While considerable research has focused on their effects under neutral salt conditions, the mechanisms through which BRs regulate photosynthesis under alkaline salt stress are less well understood. This study investigates these mechanisms, examining plant growth, photosynthetic electron transport, gas exchange parameters, Calvin cycle dynamics, and the expression of key antioxidant and Calvin cycle genes under alkaline stress conditions induced by NaHCO3. The findings indicate that NaHCO3 stress substantially impairs cucumber growth and photosynthesis, significantly reducing chlorophyll content, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), maximum photochemical efficiency (Fv/Fm), actual photochemical efficiency (ΦPSII), antenna conversion efficiency (Fv′/Fm′), and photochemical quenching coefficient (qP). This disruption suggests a severe dysregulation of the photosynthetic electron transport system, impairing electron transfer from photosystem II (PSII) to photosystem I (PSI) and subsequently the Calvin cycle. Application of exogenous 24-epibrassinolide (EBR) alleviated these effects, reducing leaf chlorosis and growth inhibition and significantly enhancing the expression of key genes within the antioxidant system (AsA-GSH cycle) and the Calvin cycle. This intervention also led to a reduction in reactive oxygen species (ROS) accumulation and improved photosynthetic performance, as evidenced by enhancements in Pn, Gs, E, Fv/Fm, ΦPSII, Fv′/Fm′, and qP. Moreover, NaHCO3 stress hindered chlorophyll synthesis, primarily by blocking the conversion from porphobilinogen (PBG) to uroporphyrinogen III (UroIII) and by increasing chlorophyllase (Chlase) and decreasing porphobilinogen deaminase (PBGD) activity. Exogenous EBR countered these effects by enhancing PBGD activity and reducing Chlase activity, thereby increasing chlorophyll content under stress conditions. In summary, EBR markedly mitigated the adverse effects of alkaline stress on cucumber leaf photosynthesis by stabilizing the photosynthetic electron transport system, accelerating photosynthetic electron transport, and promoting the Calvin cycle. This study provides valuable insights into the regulatory roles of BRs in enhancing plant resilience to alkaline stress. Full article
(This article belongs to the Special Issue Advances in Biostimulant Use on Horticultural Crops)
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13 pages, 2375 KB  
Article
Phytic Acid Delays the Senescence of Rosa roxburghii Fruit by Regulating Antioxidant Capacity and the Ascorbate–Glutathione Cycle
by Boyu Dong, Yulong Chen, Chengyue Kuang, Fangfang Da and Xiaochun Ding
Int. J. Mol. Sci. 2025, 26(1), 98; https://doi.org/10.3390/ijms26010098 - 26 Dec 2024
Cited by 3 | Viewed by 1235
Abstract
Rosa roxburghii fruit has a short postharvest shelf life, with rapid declines in quality and antioxidant capacity. This research assessed how phytic acid affects the antioxidant capacity and quality of R. roxburghii fruit while in the postharvest storage period and reveals its potential [...] Read more.
Rosa roxburghii fruit has a short postharvest shelf life, with rapid declines in quality and antioxidant capacity. This research assessed how phytic acid affects the antioxidant capacity and quality of R. roxburghii fruit while in the postharvest storage period and reveals its potential mechanism of action. The findings suggested that phytic acid treatment inhibits the production of malondialdehyde (MDA) and enhances the activities and expressions of glutathione peroxidase (GPX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) while decreasing the generation of superoxide anions (O2•−) and hydrogen peroxide (H2O2). Phytic acid treatment activates the ascorbate–glutathione (AsA-GSH) cycle and enhances the activity and expression of key enzymes in the cycle: ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). It also increases the levels of non-enzymatic antioxidants, such as ascorbic acid (AsA) and glutathione (GSH), while reducing the production of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG). Moreover, phytic acid treatment enhances the ratios of AsA/DHA and GSH/GSSG, maintaining the reduced state of the fruit. In summary, phytic acid improves antioxidant defense system and activates the AsA-GSH cycle, alleviating oxidative damage and ensuring R. roxburghii fruit quality after harvest. Full article
(This article belongs to the Special Issue Signaling and Stress Adaptation in Plants)
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25 pages, 10517 KB  
Article
Glutathione and Ascorbic Acid Accumulation in Mango Pulp Under Enhanced UV-B Based on Transcriptome
by Hassam Tahir, Muhammad Sajjad, Minjie Qian, Muhammad Zeeshan Ul Haq, Ashar Tahir, Muhammad Aamir Farooq, Ling Wei, Shaopu Shi, Kaibing Zhou and Quansheng Yao
Antioxidants 2024, 13(11), 1429; https://doi.org/10.3390/antiox13111429 - 20 Nov 2024
Cited by 4 | Viewed by 1379
Abstract
Mango (Mangifera indica), a nutritionally rich tropical fruit, is significantly impacted by UV-B radiation, which induces oxidative stress and disrupts physiological processes. This study aimed to investigate mango pulp’s molecular and biochemical responses to UV-B stress (96 kJ/mol) from the unripe [...] Read more.
Mango (Mangifera indica), a nutritionally rich tropical fruit, is significantly impacted by UV-B radiation, which induces oxidative stress and disrupts physiological processes. This study aimed to investigate mango pulp’s molecular and biochemical responses to UV-B stress (96 kJ/mol) from the unripe to mature stages over three consecutive years, with samples collected at 10-day intervals. UV-B stress affected both non-enzymatic parameters, such as maturity index, reactive oxygen species (ROS) levels, membrane permeability, and key enzymatic components of the ascorbate-glutathione (AsA-GSH) cycle. These enzymes included glutathione reductase (GR), gamma-glutamyl transferase (GGT), glutathione S-transferases (GST), glutathione peroxidase (GPX), glucose-6-phosphate dehydrogenase (G6PDH), galactono-1,4-lactone dehydrogenase (GalLDH), ascorbate peroxidase (APX), ascorbate oxidase (AAO), and monodehydroascorbate reductase (MDHAR). Transcriptomic analysis revealed 18 differentially expressed genes (DEGs) related to the AsA-GSH cycle, including MiGR, MiGGT1, MiGGT2, MiGPX1, MiGPX2, MiGST1, MiGST2, MiGST3, MiG6PDH1, MiG6PDH2, MiGalLDH, MiAPX1, MiAPX2, MiAAO1, MiAAO2, MiAAO3, MiAAO4, and MiMDHAR, validated through qRT-PCR. The findings suggest that UV-B stress activates a complex regulatory network in mango pulp to optimize ROS detoxification and conserve antioxidants, offering insights for enhancing the resilience of tropical fruit trees to environmental stressors. Full article
(This article belongs to the Special Issue Non-Enzymatic Antioxidant Molecules and Their Defense Mechanisms)
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23 pages, 5876 KB  
Article
Identification of Key Enzymes and Genes Modulating L-Ascorbic Acid Metabolism During Fruit Development of Lycium chinense by Integrating Metabolome, Transcriptome, and Physiological Analysis
by Chongxin Yin, Huichun Xie, Guigong Geng, Zuxia Li, Jianxia Ma, Xiaozhuo Wu, Quan-Sheng Qiu and Feng Qiao
Int. J. Mol. Sci. 2024, 25(21), 11394; https://doi.org/10.3390/ijms252111394 - 23 Oct 2024
Cited by 3 | Viewed by 1462
Abstract
Lycium chinense is acknowledged for its substantial nutritional benefits, particularly attributed to the high levels of ascorbic acid (AsA) found in its fruits. The “Mengqi No.1” variety of L. chinense, which is cultivated in Qinghai, is known for its high yield and [...] Read more.
Lycium chinense is acknowledged for its substantial nutritional benefits, particularly attributed to the high levels of ascorbic acid (AsA) found in its fruits. The “Mengqi No.1” variety of L. chinense, which is cultivated in Qinghai, is known for its high yield and exceptional quality. We utilized the “Mengqi No.1” variety as experimental materials and combined metabolomic, transcriptomic, and physiological analyses to investigate the metabolites, genes, and enzymes related to AsA metabolism in L. chinense fruits. The results revealed nine differential metabolites associated with AsA metabolism in L. chinense fruits across three stages, including 1D-Myo-Inositol-1,4-Bisphosphate, D-Fructose, L-(+)-Arabinose, I-Inositol, L-Arabinitol, D-Galactose-1-P, lactose, α-D-Glucose, and D-Glucose-6-P. Notably, the contents of D-Glucose-6-P, D-Galactose-1-P, and D-Fructose were increased as the fruit developed. Additionally, fresh weight, longitudinal length, and radial width were increased, while the contents of AsA and DHA were decreased. GalDH and DHAR are critical enzymes for the accumulation of AsA and DHA, exhibiting positive correlation coefficient. Furthermore, PMM1, PMM5, GME2, and GME3 were identified as key regulatory genes in the L-Galactose pathway of AsA synthesis, influencing D-Galactose-1-P, D-Glucose-6-P, α-D-Glucose, and D-Fructose. DHAR1 and DHAR2 are considered key positive regulator genes of AsA and DHA in the AsA-GSH cycle. However, the majority of genes (nine) act as negative regulators of AsA and DHA. These findings provide a foundation for the understanding of the regulatory mechanism of AsA metabolism in L. chinense fruits and offer insights into the utilization of AsA from L. chinense. Full article
(This article belongs to the Section Bioactives and Nutraceuticals)
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22 pages, 3701 KB  
Article
Physiological and Transcriptomic Analyses Reveal the Role of the Antioxidant System and Jasmonic Acid (JA) Signal Transduction in Mulberry (Morus alba L.) Response to Flooding Stress
by Xuejiao Bai, He Huang, Dan Li, Fei Yang, Xinyao Cong, Siqi Wu, Wenxu Zhu, Shengjin Qin and Yibo Wen
Horticulturae 2024, 10(10), 1100; https://doi.org/10.3390/horticulturae10101100 - 16 Oct 2024
Cited by 1 | Viewed by 1787
Abstract
In recent decades, the frequency of flooding has increased as a result of global climate change. Flooding has become one of the major abiotic stresses that seriously affect the growth and development of plants. Mulberry (Morus alba L.) is an important economic [...] Read more.
In recent decades, the frequency of flooding has increased as a result of global climate change. Flooding has become one of the major abiotic stresses that seriously affect the growth and development of plants. Mulberry (Morus alba L.) is an important economic tree in China. Flooding stress is among the most severe abiotic stresses that affect the production of mulberry. However, the physiological and molecular biological mechanisms of mulberry responses to flooding stress are still unclear. In the present study, reactive oxygen species (ROS) metabolism, antioxidant mechanism, and plant hormones in mulberry associated with the response to flooding stress were investigated using physiological and transcriptomic analysis methods. The results showed significant increases in the production rate of superoxide anion (O2•−) and the content of hydrogen peroxide (H2O2) in leaves on the 5th day of flooding stress. This led to membrane lipid peroxidation and elevated malondialdehyde (MDA) levels. Antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) exhibited enhanced activities initially, followed by fluctuations. The ascorbic acid–glutathione (AsA-GSH) cycle played a crucial role in scavenging ROS, promoting the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). Transcriptomic analysis revealed the up-regulation of the gene-encoding antioxidant enzymes (APX, MDHAR, GPX, GR, GST) involved in ROS scavenging and stress tolerance mechanisms. Jasmonic acid (JA) levels and the expression of JA synthesis-related genes increased significantly in mulberry leaves under flooding stress. This activation of the JA signaling pathway contributed to the plant’s adaptability to flooding conditions. Proline (Pro) and soluble sugar (SS) contents increased notably in response to flooding stress. Proline helped maintain cell turgor and protected enzymes and membranes from damage, while soluble sugars supported anaerobic respiration and energy supply. However, soluble protein (SP) content decreased, suggesting inhibition of protein synthesis. The study provides insights into mulberry’s flooding tolerance mechanisms, guiding future molecular breeding efforts. This summary captures the key findings and implications of the study on mulberry’s response to flooding stress, focusing on physiological and molecular mechanisms identified in the research. Full article
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20 pages, 3024 KB  
Article
Secondary Metabolites from Australian Lichens Ramalina celastri and Stereocaulon ramulosum Affect Growth and Metabolism of Photobiont Asterochloris erici through Allelopathy
by Martin Bačkor, Dajana Kecsey, Blažena Drábová, Dana Urminská, Martina Šemeláková and Michal Goga
Molecules 2024, 29(19), 4620; https://doi.org/10.3390/molecules29194620 - 29 Sep 2024
Viewed by 1356
Abstract
In the present work, the phytotoxic effects of secondary metabolites extracted from lichen Ramalina celastri (usnic acid) and lichen Stereocaulon ramulosum (a naturally occurring mixture of atranorin and perlatolic acid, approx. 3:1) on cultures of the aposymbiotically grown lichen photobiont Asterochloris erici were [...] Read more.
In the present work, the phytotoxic effects of secondary metabolites extracted from lichen Ramalina celastri (usnic acid) and lichen Stereocaulon ramulosum (a naturally occurring mixture of atranorin and perlatolic acid, approx. 3:1) on cultures of the aposymbiotically grown lichen photobiont Asterochloris erici were evaluated. Algae were cultivated on the surface of glass microfiber disks with applied crystals of lichen extracts for 14 days. The toxicity of each extract was tested at the two selected doses in quantities of 0.01 mg/disk and 0.1 mg/disk. Cytotoxicity of lichen extracts was assessed using selected physiological parameters, such as growth (biomass production) of photobiont cultures, content of soluble proteins, chlorophyll a fluorescence, chlorophyll a integrity, contents of chlorophylls and total carotenoids, hydrogen peroxide, superoxide anion, TBARS, ascorbic acid (AsA), reduced (GSH) and oxidized (GSSG) glutathione, and composition of selected organic acids of the Krebs cycle. The application of both tested metabolic extracts decreased the growth of photobiont cells in a dose-dependent manner; however, a mixture of atranorin and perlatolic acid was more effective when compared to usnic acid at the same dose tested. A higher degree of cytotoxicity of extracts from lichen S. ramulosum when compared to identical doses of extracts from lichen R. celastri was also confirmed by a more pronounced decrease in chlorophyll a fluorescence and chlorophyll a integrity, decreased content of chlorophylls and total carotenoids, increased production of hydrogen peroxide and superoxide anion, peroxidation of membrane lipids (assessed as TBARS), and a strong decrease in non-enzymatic antioxidants such as AsA, GSH, and GSSG. The cytotoxicity of lichen compounds was confirmed by a strong alteration in the composition of selected organic acids included in the Krebs cycle. The increased ratio between pyruvic acid and citric acid was a very sensitive parameter of phytotoxicity of lichen secondary metabolites to the algal partner of symbiosis. Secondary metabolites of lichens are potent allelochemicals and play significant roles in maintaining the balance between mycobionts and photobionts, forming lichen thallus. Full article
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20 pages, 18707 KB  
Article
Salicylic Acid and Melatonin Synergy Enhances Boron Toxicity Tolerance via AsA–GSH Cycle and Glyoxalase System Regulation in Fragrant Rice
by Muhammad Imran, Emilie Widemann, Sarfraz Shafiq, Ali Bakhsh, Xiaoyuan Chen and Xiangru Tang
Metabolites 2024, 14(10), 520; https://doi.org/10.3390/metabo14100520 - 26 Sep 2024
Cited by 2 | Viewed by 1521
Abstract
Background: Boron is an essential micronutrient for plant growth and productivity, yet excessive boron leads to toxicity, posing significant challenges for agriculture. Fragrant rice is popular among consumers, but the impact of boron toxicity on qualitative traits of fragrant rice, especially aroma, remains [...] Read more.
Background: Boron is an essential micronutrient for plant growth and productivity, yet excessive boron leads to toxicity, posing significant challenges for agriculture. Fragrant rice is popular among consumers, but the impact of boron toxicity on qualitative traits of fragrant rice, especially aroma, remains largely unexplored. The individual potentials of melatonin and salicylic acid in reducing boron toxicity are less known, while their synergistic effects and mechanisms in fragrant rice remain unclear. Methods: Thus, this study investigates the combined application of melatonin and salicylic acid on fragrant rice affected by boron toxicity. One-week-old seedlings were subjected to boron (0 and 800 µM) and then treated with melatonin and salicylic acid (0 and 100 µM, for 3 weeks). Results: Boron toxicity significantly impaired photosynthetic pigments, plant growth, and chloroplast integrity while increasing oxidative stress markers such as hydrogen peroxide, malondialdehyde, methylglyoxal, and betaine aldehyde dehydrogenase. Likewise, boron toxicity abridged the precursors involved in the 2-acetyl-1-pyrroline (2-AP) biosynthesis pathway. However, individual as well as combined application of melatonin and salicylic acid ameliorated boron toxicity by strengthening the antioxidant defense mechanisms—including the enzymes involved during the ascorbate–glutathione (AsA–GSH) cycle and glyoxalase system—and substantially improved 2-AP precursors including proline, P5C, Δ1-pyrroline, and GABA levels, thereby restoring the 2-AP content and aroma. These findings deduce that melatonin and salicylic acid synergistically alleviate boron toxicity-induced disruptions on the 2-AP biosynthesis pathway by improving the 2-AP precursors and enzymatic activities, as well as modulating the physio-biochemical processes and antioxidant defense system of fragrant rice plants. Conclusions: The findings of this study have the potential to enhance rice productivity and stress tolerance, offering solutions to improve food security and sustainability in agricultural practices, particularly in regions affected by environmental stressors. Full article
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16 pages, 6872 KB  
Article
Salicylic Acid Treatment Ameliorates Postharvest Quality Deterioration in ‘France’ Prune (Prunus domestica L. ‘Ximei’) Fruit by Modulating the Antioxidant System
by Xinling Zhang, Yuxing Liu, Weida Zhang, Wanting Yang, Shuaibing An, Minrui Guo and Guogang Chen
Foods 2024, 13(18), 2871; https://doi.org/10.3390/foods13182871 - 10 Sep 2024
Cited by 12 | Viewed by 2428
Abstract
The potential of salicylic acid (SA) in delaying postharvest fruit senescence has been extensively documented; nevertheless, its effect on antioxidant activity and quality of ‘France’ prune fruit is largely unknown. The study investigated the effects of SA (0.5 mM) on postharvest quality deterioration [...] Read more.
The potential of salicylic acid (SA) in delaying postharvest fruit senescence has been extensively documented; nevertheless, its effect on antioxidant activity and quality of ‘France’ prune fruit is largely unknown. The study investigated the effects of SA (0.5 mM) on postharvest quality deterioration of ‘France’ prune fruit. Results indicated that SA impeded the increase in respiration rate and weight loss, and mitigated the decrease of soluble solids content (SSC), titratable acidity (TA) content, firmness, and hue angle. SA sustained the ascorbate-glutathione cycle by inducing the production of ascorbic acid (AsA) and glutathione (GSH) and attenuates flavonoids, total phenols, and anthocyanins degradation by inhibiting polyphenol oxidase (PPO) activity and PdPPO. Moreover, SA significantly improved superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), and glutathione reductase (GR) activities and gene expression levels, sustained higher 2,2′-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging capacity, ferric reducing antioxidant power (FRAP), and hydroxyl radical (·OH) inhibition capacity, and impeded the production of hydrogen peroxide (H2O2) and superoxide anion (O2•−). Overall, SA improved the antioxidant capacity by inducing the synthesis of defense response-related substances and promoting antioxidant enzyme activities to sustain the storage quality of ‘France’ prune fruit. Full article
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27 pages, 2997 KB  
Review
Drought Stress Tolerance in Rice: Physiological and Biochemical Insights
by Aysha Siddika Jarin, Md. Moshiul Islam, Al Rahat, Sujat Ahmed, Pallab Ghosh and Yoshiyuki Murata
Int. J. Plant Biol. 2024, 15(3), 692-718; https://doi.org/10.3390/ijpb15030051 - 21 Jul 2024
Cited by 22 | Viewed by 7816
Abstract
Rice (Oryza sativa L.), an important food crop, necessitates more water to complete its life cycle than other crops. Therefore, there is a serious risk to rice output due to water-related stress. Drought stress results in morphological changes, including the inhibition of [...] Read more.
Rice (Oryza sativa L.), an important food crop, necessitates more water to complete its life cycle than other crops. Therefore, there is a serious risk to rice output due to water-related stress. Drought stress results in morphological changes, including the inhibition of seed germination, reduced seeding growth, leaf area index, flag leaf area, increased leaf rolling, as well as the decrement of yield traits, such as plant height, plant biomass, number of tillers, and 1000-grain yield. Stress also causes the formation of reactive oxygen species (ROS) such as O2, H2O2, and OH, which promote oxidative stress in plants and cause oxidative damage. The process of oxidative degradation owing to water stress produces cell damage and a reduction in nutrient intake, photosynthetic rate, leaf area, RWC, WUE, and stomatal closure, which may be responsible for the decrement of the transpiration rate and plant dry matter under decreasing soil moisture. Plants have the ability to produce antioxidant species that can either be enzymatic (SOD, POD, CAT, GPX, APX) or non-enzymatic (AsA, GSH) in nature to overcome oxidative stress. During drought, several biochemical osmoprotectants, like proline, polyamines, and sugars, can be accumulated, which can enhance drought tolerance in rice. To meet the demands of an ever-growing population with diminishing water resources, it is necessary to have crop varieties that are highly adapted to dry environments, and it may also involve adopting some mitigation strategies. This study aims to assess the varying morphological, physiological, and biochemical responses of the rice plant to drought, and the various methods for alleviating drought stress. Full article
(This article belongs to the Section Plant Response to Stresses)
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