Plant Antioxidant Research Articles

Effect of habitat variation on physiological response, chemical compositions and antioxidants, of Ephedra alata (stapf) Andr

Ephedra alata is a widespread shrub found in various countries that originates from Southwestern North America, Southern Europe, and North Africa. This medicinal plant is part of the Ephedra genus, family Ephedraceae. The plant was collected from Wadi Arar, Northern Regions, and Wadi Hagul, Cairo/Suez Road, to investigate how the plant's chemical composition and antioxidant capacities are affected by habitat variation. The findings revealed notable variations in the total phenolic, total flavonoid, antioxidant activity, and soil analysis aspects between the two regions under investigation. The reducing ability of ferric ion of the plant extracts is present as 858.0 ± 38.95 μMTE/mg extract of plant growing in Arar region, while the reducing ability of E. alata growing in Egypt has Ec50 (650.0 ± 29.85) by FRAB methods. The plants extract of E. alata quench both ABTS and DPPH free radical. The sample showed higher ABTS scavenging activity (228± 195 μMTE / mg for the plant growing in Arar region while the plant ephedra growing in Wadi Hagul showed lower scavenging activity 185± 285 Umte/MG) in addition the two-plant showed high antioxidant activity when evaluated by DPPH radical scavenging test with IC50 (458.0 ± 38.95 ug/mL and 425± 28.9/mL). Total phenolic was determined by Folin-Ciocalteau method, However, the aluminum chloride consider was additionally employed to estimate the total flavonoid., the results showed high phenolic content (62.177 mg GAE), and high flavonoid content (39.6148± 3.816mg/g extract) for plant growing in Arar region than plant growing in Wadi Hagul, which have (45.60 mg GAE and 29.615 mg rutin/ mg Extract). Finally, the study reflects high variation between two habitats, this corresponding to two variations in climate change and different environmental conditions.

Effect of coexisting nutrient divalent cations on cadmium transport in soil-herbal crop systems

Cadmium (Cd) pollution in Chinese herbal medicines poses a serious risk to medication safety. Regulating Cd uptake, transport, and accumulation in plants through ion-ion interactions offers a novel, environmentally sustainable, and practical approach to address this issue. However, the effects and underlying mechanisms of coexisting divalent cations zinc (Zn), magnesium (Mg), and manganese (Mn) on Cd uptake by Ligusticum sinense cv. Chuanxiong (L. chuanxiong) have not been comprehensively studied or well understood. In this study, the application of coexisting these cations (Zn, Mg, Mn) could significantly promote the growth of L. chuanxiong (21.11%–36.04%) and change the mobility of Cd in the soil-crop system. Specifically, adding Zn decreased Cd content in soil and plants by 18.23% and 20.62%, respectively, while Mg increased it by 10.99% and 62.27%. Mn addition, however, had no significant effect. Similar trends in soil enzyme activity were also observed with Zn, Mg, and Mn treatments. Simultaneously, the findings explore how coexisting divalent cations influence plant physiological responses, including photosynthesis and antioxidant capacities, enabling L. chuanxiong to better manage Cd stress. This study underscores the potential of ion-to-ion interactions as an effective approach to mitigate Cd accumulation, offering a practical and sustainable solution for enhancing the safety of Chinese herbal medicines. Additionally, the effects of mixed cation applications on Cd dynamics are complex, shaped by interactions between ion types, dosages, and their specific properties. These insights provide a foundation for developing more effective remediation strategies for Cd-contaminated soils, particularly in the cultivation of medicinal plants.

Arbuscular mycorrhizal fungi enhance drought resistance and alter microbial communities in maize rhizosphere soil

Although the benefits of inoculation with arbuscular mycorrhizal fungi (AMF) for mitigating drought stress and enhancing plant growth of host are well‐studied, our understanding of their interactions with soil attributes and rhizosphere microbial communities remains limited. In the present study, we conducted a pot experiment to explore how AMF affects maize growth, antioxidant activity, soil properties, and the rhizosphere microbial communities under drought stress. The results showed that AMF inoculation during drought stress resulted in improved maize seedling growth, significantly increasing plant biomass (42.7%), chlorophyll content (13.4%), and antioxidant capacity. It also enhanced soil nutrient availability and microbial biomass. We observed significant shifts in the structure and composition of the rhizosphere microbial community with AMF inoculation under drought conditions when compared to those under well-watered conditions. Significantly, bacterial diversity and composition showed greater sensitivity to drought stress than fungal communities. This was attributed to plants preferentially reducing the supply of carbon sources to bacterial rather than to fungal communities under drought conditions. AMF inoculation also enhanced the complexity (e.g., degree) and stability of the rhizosphere microbial ecological network, suggesting closer ecological interactions within the soil microbial community. Furthermore, bacterial diversity and richness played a more important role in soil function than those of fungal communities under drought stress, particularly with AMF inoculation. Overall, our findings suggest that AMF inoculation alters soil microbial diversity and interactions, highlighting their key roles in enhancing plant stress tolerance and mitigating the negative effects of drought on agricultural ecosystems.

The Application of Conventional and Organic Fertilizers During Wild Edible Species Cultivation: A Case Study of Purslane and Common Sowthistle

The introduction of alternative crops, including wild edible and medicinal plants, in organic cultivation systems presents an attractive approach to producing healthy and high-quality products due to their content in beneficial compounds and increased nutritional value. The current study evaluated the impact of organic and conventional fertilization on the growth, quality, nutrient status and stress response of the two wild edible species, e.g., purslane (Portulaca oleracea L.) and common sowthistle (Sonchus oleraceus L.), under field conditions. The fertilization treatments included the following: a control (NoFert) treatment with no fertilizers added, base dressing with conventional fertilization (CoFert), base dressing with organic fertilization (OrFert), base dressing and side dressing with conventional fertilization (OrFert + SCoFert) and base dressing and side dressing with organic fertilization (CoFert + SCoFert). Organic fertilization was carried out using a commercial vinasse-based organic fertilizer. In both purslane and common sowthistle, the application of organic fertilizers provided comparable or even enhanced plant growth traits, macronutrient content (i.e., P and K for purslane, and N for sowthistle) and quality (i.e., total soluble solids) compared to the application of conventional fertilizers. On the other hand, conventional fertilization with supplementary fertilization positively influenced the plant growth of purslane (i.e., plant height and stems biomass), as well as its physiological parameters (i.e., chlorophylls content), total phenolics content and antioxidant capacity (i.e., DPPH and FRAP). Similarly, conventional fertilization led to increased total phenolics and antioxidants in common sowthistle, while variable effects were observed regarding plant physiology, stress response and antioxidant capacity indices. In conclusion, the use of organic fertilization in both purslane and common sowthistle exhibited a performance similar to that of conventional fertilization, although further optimization of fertilization regimes is needed to improve the quality of the edible products.

Metabolomic and transcriptomic analyses reveal the regulation mechanism of postharvest light-induced phenolics accumulation in mango peel

Phenolics are important secondary metabolites and antioxidants in plants. Mango fruit accumulate abundant phenolic compounds, while the effect of light on the accumulation of different phenolic components in mango peel and the relevant molecular mechanism are still unknown. In this study, mature ‘Guifei’ mango fruit was subjected to postharvest UV-B/white light treatment, fruit peel was sampled for metabolomic and transcriptomic analyses. The results showed that light induced the accumulation of anthocyanins, flavonoids, and phenolics, thus increasing the antioxidant capacity in mango peel. A total of 1223 phenolic metabolites were detected in mango peel, 36 phenolic compounds were defined as key differentially accumulated metabolites (DAMs) regulated by light. Among the DAMs, the accumulation of 33 compounds was promoted by light, and 30 of these were flavonoids. Light up-regulated most phenolics biosynthesis and light signaling pathway genes and also regulated expression of plant hormone signaling pathway genes. Transcription factors (TFs) such as MYB, C2H2 and HSF were identified as candidates regulating phenolics biosynthesis in mango. Our findings not only provide information for commercial application of light in promoting mango fruit appearance and increasing phenolics content and antioxidant capacity, but also reveal important aspects of the molecular regulation of light-induced phenolics accumulation in mango peel.

Addition of polyphenolic extracts of Myrtus communis and Arbutus unedo fruits to whey: valorization of a common dairy waste product as a functional food.

Whey, a nutrient-rich byproduct of the dairy sector, possesses high potential for creating novel nutraceutical products. The present study investigates a potential new functional food by incorporating polyphenolic extracts from Myrtus communis and Arbutus unedo fruits into whey in both liquid (LA) and powder (PA) addition forms. Chemical, microbiological, physical stability and antioxidant activity were monitored for 60 days (from T0 to T60). Both LA and PA of fruit extracts remained chemically stable for the whole period, except for A. unedo PA, which showed a decline in polyphenols after T45. Enriched whey samples showed higher antioxidant activity than pure whey. Microbiological analysis revealed the presence of lactic acid bacteria, indicating potential prebiotic effects. However, the high tannin concentration of A. unedo extracts partially modified the casein micelle structure. Whey enriched with Mediterranean fruit extracts shows great potential as a functional food, combining the benefits of plant antioxidants, probiotic bacteria and good stability. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Assessing light spectrum impact on growth and antioxidant properties of basil family microgreens

Understanding the influence of light spectra on plant growth and antioxidant activities is crucial for optimizing cultivation practices and enhancing crop quality. In this study, we investigated the effects of different light treatments on growth parameters and antioxidant activities in five plant species: peppermint, Thai basil, cumin, lemon basil, and green holy basil. Our results revealed distinct responses to varying light spectra, with green light consistently promoting taller plant heights across all species. Additionally, blue light induced notable increases in plant width for certain species. Analysis of antioxidant activities demonstrated dynamic fluctuations in Total Phenolic Content (TPC) and Flavonoid Content (TFC) among different light treatments and plant species. While white and red light generally promoted higher TPC levels, blue light unexpectedly exhibited the highest TPC levels at specific time points. Moreover, investigation into DPPH Radical Scavenging activity revealed diverse temporal responses to light spectra, with blue light demonstrating exceptional activity at early stages and white and red light showing heightened activity at later time points. These findings underscore the importance of tailored light regimes in optimizing growth parameters and enhancing antioxidant activities in cultivated plants, thereby offering promising avenues for sustainable agriculture and food production practices.

Mycorrhization and chemical seed priming boost tomato stress tolerance by shifts of primary and defence metabolic pathways.

Priming modulates plant stress responses before the stress appears, increasing the ability of the primed plant to endure adverse conditions and thrive. In this context, we investigated the effect of biological (i.e., arbuscular mycorrhizal fungi, AMF) agents and natural compounds (i.e., salicylic acid applied alone or combined with chitosan) against water deficit and salinity on a commercial tomato genotype (cv. Moneymaker). Effects of seed treatments on AMF colonization were evaluated, demonstrating the possibility of using them in combination. Responses to water and salt stresses were analysed on primed plants alone or in combination with the AMF inoculum in soil. Trials were conducted on potted plants by subjecting them to water deficit or salt stress. The effectiveness of chemical seed treatments, both alone and in combination with post-germination AM fungal inoculation, was investigated using a multidisciplinary approach that included eco-physiology, biochemistry, transcriptomics, and untargeted metabolomics. Results showed that chemical seed treatment and AM symbiosis modified the tomato response to water deficit and salinity triggering a remodelling of both transcriptome and metabolome, which ultimately elicited the plant antioxidant and osmoprotective machinery. The plant physiological adaptation to both stress conditions improved, confirming the success of the adopted approaches in enhancing stress tolerance.

Impact of bioinoculants on growth enhancement, physicochemical characteristics, biochemical profiles, and enzymatic defense mechanisms in tomato (Lycopersicum esculentum)

The excessive use of fungicides in agriculture causes challenges like pathogen resistance, soil and water contamination, and potential health risks. Sustainable options like Pseudomonas spp. and yeast are being explored as bioinoculants to promote plant growth and inhibit fungal proliferation. 87 isolates, comprising 36 fluorescent Pseudomonas spp. and 51 yeast isolates were obtained from healthy fruits and vegetables. Yeast (YFSL) and Pseudomonas (PFSL) isolates significantly (p < 0.05) inhibited the in-vitro growth of Fusarium solani and Drechslera sp. Experiments in a screen house for 90 days used a randomized block design to study the effects of bioinoculants on plant and fruit health. Moreover, plants and fruits treated with these bioinoculants showed increased levels of salicylic acid (66.14%), total phenolic content (59.67%), chlorophyll (24.31%), carbohydrates (40.38%), phosphorus (0.24%), and antioxidant activity (90%). The treatments displayed higher levels of plant defensive enzymes, chitinase (0.09 mg/h/protein) and β-1-3-glucanase (0.093 mg/h/protein). The increased concentrations of antioxidant enzymes like SOD (0.07 U/L), POD (0.23 U/L), and APX (0.24 U/L) were also observed in the fruits of bio-inoculated plants. However., the difference in results was non-significant (P ≤ 0.05). This study demonstrates the Efficacy of bioinoculants in improving plant growth, compositional characteristics, and antioxidant activities while reducing losses in tomato plants and fruits.

Foliar Methyl Jasmonate Application Activates Antioxidant Mechanisms to Counteract Water Deficits and Aluminum Stress in Vaccinium corymbosum L.

Due to climate change, water deficits (WDs) and aluminum (Al) toxicity are increasing, affecting plants, especially crops such as blueberries (Vaccinium corymbosum L.). The application of methyl jasmonate (MeJA) could mitigate these effects. This work aimed to evaluate the effective MeJA dose to overcome oxidative stress provoked by combined WD+Al stress in blueberries. Plants of Al-sensitive (Star) and Al-resistant (Legacy) cultivars were exposed to control (Al at 65 mg/Kg, 80% field capacity), WD+Al (50% field capacity; Al at 1665 mg/Kg), and WD+Al treatment with different foliar MeJA doses (10, 50, and 100 μM) during 7 and 21 days. Data revealed that plants exposed to WD+Al and treated with 50 µM MeJA reduced Al up to 3.2-fold in roots and 2.7-fold in leaves and improved water potential (Ψw) up to 2.5-fold. The sensitive cultivar decreased the relative growth rate under WD+Al, increasing by 1.9-fold with 50 µM MeJA. Under WD+Al stress, all MeJA doses mitigated the decrease in relative water content in Al-resistant cultivars, restoring values like control plants. In the sensitive cultivar, 50 µM MeJA increased photosynthesis (1.5-fold) and stomatal conductance (1.4-fold), without changes in transpiration. Lipid peroxidation decreased (1.2-fold) and increased antioxidant activity (1.8-fold), total phenols (1.6-fold), and superoxide dismutase activity (3.3-fold) under WD+Al and 50 µM-MeJA. It was concluded that the most effective dose to alleviate the WD+Al stress was 50 µM MeJA due to the activation of antioxidants in blueberry plants. Therefore, the MeJA application could be a potential strategy for enhancing the resilience of V. corynbosum exposed to WD+Al stress.

Effect of In Vitro Pretreatment with Ag-Containing Amino Acid Nanofibers on Biometrics and Antioxidant Activity in Drought-Stressed Ex Vitro-Adapted Stevia rebaudiana Bertoni

Biotechnological methods prevent the destruction of natural populations of medicinal plants due to climate change and developing agriculture. This study evaluates the effects of in vitro pretreatment with two types of silver-containing amino acid nanofibers (NF-1%Ag and NF1-Ag salt) on the drought tolerance of ex vitro soil-adapted Steviia rebaudiana Bertoni. The duration of the drought was five days. The data suggested that the pretreatment with the studied nanofibers during plant propagation enhanced the plant tolerance to drought stress manifested in a smaller decrease in plant biomass accumulation and a smaller increase in sugar content. The pretreatment with the two tested nanoparticles of well-watered plants increased the leaf fresh biomass accumulation of the ex vitro-adapted S. rebaudiana compared to the untreated WW control plants. The highest values were reported at 10 mg L−1 NF1-Ag salt. Five days of drought led to a decrease in the leaf fresh biomass compared to the WW plants, with the recorded lowest reduction again at 10 mg L−1 NF1-Ag salt. These observations correlate with antioxidant activity improvement. The results show that adding 10 mg L−1 NF1-Ag salt to the MS medium led to higher ex vitro-adapted S. rebaudiana resistance to water deficit than 100 mg L−1. This paper discusses the impact of the selected nanofibers on parameters characterizing plant growth and antioxidant activity of drought-stressed ex vitro-adapted Stevia rebaudiana plants.

Seawater-induced Salinity Enhances Antioxidant Capacity by Modulating Morpho-physiological and Biochemical Responses in Catharanthus roseus

Salt stress impedes plant growth and development due to several factors, including the generation of cellular oxidative stressors. This study aimed to assess the impacts of seawater-induced salinity on the plant development, physio-biochemical responses, and antioxidant capacity of Catharanthus roseus grown in a variety of seawater (4, 8, and 12 dS/m) for varying durations (60, 90, and 120 days). The experiment was laid out in a randomized complete block design with five replications. The results demonstrated that C. roseus successfully endured moderate salinity (8 dS/m) by maintaining plant height, number of leaves, branches, relative water content, and chlorophyll content with a minimum drop in dry biomass (25%) in a time- and dose-dependent approach. Furthermore, greater proline and soluble sugar contents suggested that C. roseus possessed enhanced osmoprotective capabilities to counteract osmotic stress caused by salinity. Conversely, all growth indicators decreased significantly at high salinity (12 dS/m). Increased levels of antioxidant enzyme activity catalase and ascorbate peroxidase, phenol and flavonoid, 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid indicate a coordinated function for antioxidant components in regulating reactive oxygen species (ROS) at low (4 dS/m) and moderate (8 dS/m) salinities. In contrast, excessive salinity (12 dS/m) led to a burst of ROS, as seen by elevated levels of hydrogen peroxide, malondialdehyde, and electrolyte leakage that greatly reduced total dry matter (72%), especially on days 120. The ion studies on plants subjected to salinity revealed that most Na+ remained in the roots. In contrast, most K+, Ca2+, and Mg2+ are deposited more firmly in the leaves than in the roots. The findings imply that C. roseus may tolerate moderate salinity (8 dS/m) owing to its enhanced antioxidant defense system and osmolytes, which trigger antioxidant enzymes and maintain ionic balance.

Extraction and In Vitro and In Vivo Antioxidant Activity Evaluation of Polyphenols from Lychee Pericarp

Background Finding a new promising plant antioxidant to combat or prevent cardiovascular disease remains a major challenge for researchers. Lychee pericarp, which includes a variety of polyphenols, is a prospective source of botanical antioxidants. Purpose In response to this issue, we assessed the effect of lychee bark extract on oxygen radical scavenging capacity and separate vascular protective ability in vivo. Methods In the current study, the lychee pericarp enrichment product (RLP) was obtained by optimizing an extraction method and separated using modern separation methods. The structure of the isolated compounds was assessed using 1H-NMR, 13C-NMR, and electrospray ionization-mass spectrometry, and the content of polyphenols obtained from the extract was quantified using the area normalization method. In addition, the capacity of RLP to scavenge oxygen radicals in vitro was assessed using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and T-AOC (total antioxidant capacity) techniques. Furthermore, an isoprenaline hydrochloride (ISO)-induced rat model of acute myocardial ischemia was established, and four biochemical indicators were used to assess the effect of lychee bark extract on oxygen radical scavenging capacity and cardiovascular protective ability in vivo. Results RLP extraction produced 11 chemicals, 6 of which were structurally assessed. Quantitative analysis revealed that epicatechin, PC-C(epicatechin-(4β↓8,2β↓O↓7)-epicatechin-(4β↓8)-epicatechin), type A proanthocyanidin trimer, proanthocyanidin A2, and type B proanthocyanidin dimer were the most abundant polyphenols. The in vitro DPPH and T-AOC findings revealed that RLP exhibited strong free radical scavenging activity, approximately 1.5-fold that of vitamin C. The four biochemical indicators confirmed the antioxidant activity and cardiovascular protective ability of RLP in vivo. Conclusion RLP has good in vivo and in vitro antioxidant activity, confirming lychee pericarp as a prospective source of botanical antioxidants.

Removal of formaldehyde from indoor air by potted Sansevieria trifasciata plants: dynamic influence of physiological traits on the process.

Plant-based removal of indoor formaldehyde is a widely studied method, yet little is known about the dynamic changes in this process. In this study, potted Sansevieria trifasciata Prain plants were exposed to 5-ppm formaldehyde gas concentration for 7days. The results showed that formaldehyde exposure led to plant stress, affected photosynthesis, and damaged membrane lipids, as evidenced by a decrease in chlorophyll content, an increase in Chl a/b ratio and malondialdehyde content. However, the formaldehyde removal ability of the plants increased over the first 5days, peaking at 18.02mgh-1kg-1 dry weight on the 5th day. This trend was correlated with changes in various indicators in the plant roots, including phytohormone and antioxidant enzymes. Notably, catalase activity in the roots behaved differently from other indicators. The indicators in the leaves showed turning points around the 3rd day due to the direct exposure of the leaves to formaldehyde. The relative abundance of endophytes indicated an increase in plant growth-promoting bacteria, which helped the plant cope with formaldehyde stress. The study suggests that under formaldehyde stress, plants manage active oxygen content by increasing phytohormones and regulating redox reactions. This enhances their tolerances to formaldehyde, thereby improving their ability to remove formaldehyde and aiding recovery after formaldehyde exposure.

Effects of seed coating with (titanium dioxide and selenium) nanoparticles on fenugreek (Trigonella foenum graecum L.) plant growth and antioxidant activity

Background: The fenugreek plant is a kind of herbaceous plant that resembles a clover. It is extensively used as a spice and condiment, as well as a medicinal plant. Studying the effect of seed coating on fenugreek is an important step to learn about the effects it imprints on plant growth and its antioxidant activity when its seeds are coated by nanoparticles of titanium and selenium. Methods: To study the effects of seed coating with Nanoparticles of Titanium dioxide at concentrations of (0, 100, 200, 300, and 400) ppm and selenium at concentrations of (0, 20, 40, 60, and 80) ppm on shoot length, number of leaves per plant, carbohydrate %, protein %, and antioxidant activity peroxidase %, single and two way interaction on fenugreek’s growth is taken into account. Treatments are designed as a properly randomized factorial experiment (5×5×3), with three replicates in a totally randomized design.Results: It was revealed that a single application of the previously mentioned ingredients had a significant impact on fenugreek growth and antioxidant activity, especially at high concentrations.Conclusions: Plant physiological properties were favorably influenced by seed coating with (Titanium dioxide and Selenium) nanoparticles. Based on the results of TiO2 NPs’ effect on seed germination and early seedling growth, it is possible that NPs aided in seed water absorption, increased seed ability to absorb and utilize efficiently, and activated and promoted hydrolytic enzymes in the seed antioxidant system.Keywords: Titanium dioxide; Selenium; Nanoparticles; Antioxidant activity; Fenugreek

Evaluating the effects of rice husk derived nanosilica on growth, photosynthesis, and antioxidant activity in hybrid maize

Drought stress was exacerbated by changing climatic conditions and impact the plant water relations from the cellular to whole plant level, thereby reducing the crop productivity and causing economic losses in agriculture. The present study was aimed to explore the potentials of nanosilica synthesized from rice husk in improving growth and drought stress tolerance in maize. Synthesized nanosilica from rice husk has spherical morphology, amorphous structure, siloxane bonding and higher purity (99.1 %). Soil application of varied levels of synthesized nanosilica (0, 5, 10, 15, 20, 30 and 40 mg kg−1) was tested with hybrid maize plants grown under irrigated and drought stress (100 and 50 % field capacity, respectively). The results of the study revealed that, drought stress has adverse effect on plant growth, biomass production and physiological parameters. However soil application of nanosilica has significantly improved growth, physiological and biochemical attributes of both irrigated and drought stressed plants. Nanosilica application at 20 mg kg−1 for irrigated and 30 mg kg−1 for drought stressed hybrid maize plants has recorded higher plant height, biomass, chlorophyll a, chlorophyll b, superoxide dismutase, peroxidase, phenols, soluble proteins and considerably decreased the proline, electrolyte leakage and melondialdehyde content in hybrid maize. In contrary, higher doses of nanosilica (>30 mg kg−1) caused a slight reduction in plant growth and antioxidant activity under both the water regimes. Hence, we conclude that, soil application of 20 and 30 mg kg−1 nanosilica synthesized from rice husk had a positive effect on plant growth and development besides aided in mitigating drought stress.

Microbiomes-Plant Interactions and K-Humate Application for Salinity Stress Mitigation and Yield Enhancement in Wheat and Faba Bean in Egypt’s Northeastern Delta

Salinity, resulting from climate change and excessive mineral fertilization, burdens farmers and negatively impacts soil and water ecosystems in the Northeastern Nile Delta. Organic and biological approaches are crucial for addressing these issues. This study examined the effects of individual and combined inoculations with cyanobacteria, yeast, and Arbuscular Mycorrhizal Fungi (AMF), with or without K-Humate and reducing Nitrogen, phosphorus and potassium (NPK) mineral fertilizers application rates to crop quality of wheat and faba bean. In preliminary laboratory experiments, the interactive effects of these microbiomes on plant antioxidant and soil enzyme production were examined under salinity stress. Results showed that co-inoculation, especially with K-Humate, yielded superior outcomes compared to individual inoculations. These findings were validated by a field trial conducted in saline-alkaline soil in the Northeastern Nile Delta region. All biological treatments 25% of recommended doses, and enhancing salinity tolerance, increasing yield, and improving enhanced rhizosphere microbial activity, including soil enzyme activity, AMF colonization, spore density, and the total numbers of bacteria, cyanobacteria, and yeast. These effects were further amplified by K-Humate and were more pronounced with combined inoculations than with individual ones, leading to improved soil fertility and significant increases in both crop quantity and quality compared to control treatments. The triple treatment, combining cyanobacteria, yeast, and mycorrhizae in the presence of K-Humate while reducing the mineral NPK rate by 75%, achieved superior increases in the productivity of wheat grains and faba bean seeds, reaching 54.72% and 128.92%, respectively, compared to the 100% NPK mineral control. This treatment also significantly improved crop quality, with notable increases in nitrogen, potassium, phosphorus, and protein percentages in wheat grains and faba bean seeds. Microbiomes-interaction increased potassium uptake over sodium, enhancing the plant’s potassium/sodium ratio and improving salt stress tolerance. This approach reduces reliance on costly mineral fertilizers, enabling bio-organic farming in marginal lands, optimizing resource utilization, and preserving natural resources.

Integration of physiology, genomics and microbiomics analyses reveal the biodegradation mechanism of petroleum hydrocarbons by Medicago sativa L. and growth-promoting bacterium Rhodococcus erythropolis KB1

Despite the effectiveness of microbial-phytoremediation for remediating total petroleum hydrocarbons (TPH)-contaminated soil, the underlying mechanisms remain elusive. This study investigated the whole-genome and biological activity of Rhodococcus erythropolis KB1, revealing its plant growth promotion (PGP), TPH degradation, and stress resistance capabilities. Phytoremediation (using alfalfa) and plant-microbial remediation (using alfalfa and KB1) were employed to degrade TPH. The highest TPH degradation rate, reaching 95%, was observed with plant-microbial remediation. This is attributed to KB1′s ability to promote alfalfa growth, induce the release of signaling molecules to activate plant antioxidant enzymes, actively recruit TPH-degrading bacteria (e.g., Sphingomonas, Pseudomonas, C1-B045), and increase soil nitrogen and phosphorus levels, thereby accelerating TPH degradation by both plants and microorganisms. This study demonstrates that R. erythropolis KB1 holds great potential for enhancing the remediation of TPH-contaminated soil through its multifaceted mechanisms, particularly in plant-microbial remediation strategies, providing valuable theoretical support for the application of this technology.

Maize Endophytic Plant Growth-Promoting Bacteria Peribacillus simplex Can Alleviate Plant Saline and Alkaline Stress.

Soil salinization is currently one of the main abiotic stresses that restrict plant growth. Plant endophytic bacteria can alleviate abiotic stress. The aim of the current study was to isolate, characterize, and assess the plant growth-promoting and saline and alkaline stress-alleviating traits of Peribacillus simplex M1 (P. simplex M1) isolates from maize. One endophytic bacterial isolate, named P. simplex M1, was selected from the roots of maize grown in saline-alkali soil. The P. simplex M1 genome sequence analysis of the bacteria with a length of 5.8 Mbp includes about 700 genes that promote growth and 16 antioxidant activity genes that alleviate saline and alkaline stress. P. simplex M1 can grow below 400 mM NaHCO3 on the LB culture medium; The isolate displayed multiple plant growth-stimulating features, such as nitrogen fixation, produced indole-3-acetic acid (IAA), and siderophore production. This isolate had a positive effect on the resistance to salt of maize in addition to the growth. P. simplex M1 significantly promoted seed germination by enhancing seed vigor in maize whether under normal growth or NaHCO3 stress conditions. The seeds with NaHCO3 treatment exhibited higher reactive oxygen species (ROS) levels than the maize in P. simplex M1 inoculant on maize. P. simplex M1 can colonize the roots of maize. The P. simplex M1 inoculant plant increased chlorophyll in leaves, stimulated root and leaf growth, increased the number of lateral roots and root dry weight, increased the length and width of the blades, and dry weight of the blades. The application of inoculants can significantly reduce the content of malondialdehyde (MDA) and increase the activity of plant antioxidant enzymes (Catalase (CAT), Superoxide Dismutase (SOD), and Peroxidase (POD)), which may thereby improve maize resistance to saline and alkaline stress. Conclusion: P. simplex M1 isolate belongs to plant growth-promoting bacteria by having high nitrogen concentration, indoleacetic acid (IAA), and siderophore, and reducing the content of ROS through the antioxidant system to alleviate salt alkali stress. This study presents the potential application of P. simplex M1 as a biological inoculant to promote plant growth and mitigate the saline and alkaline effects of maize and other crops.

Antioxidant Function and Application of Plant-Derived Peptides.

With the development of society and the improvement of people's health consciousness, the demand for antioxidants is increasing. As a natural antioxidant with no toxic side effects, antioxidant peptides are widely used in food, cosmetics, medicine, and other fields because of their strong antioxidant capacity and easy absorption by the human body. Plant-derived antioxidant peptides have attracted more attention than animal-derived antioxidant peptides because plants are more diverse than animals and produce a large number of protein-rich by-products during the processing of their products, which are the main source of antioxidant peptides. In this review, we summarize the source, structure and activity, other biological functions, mechanism of action, and comprehensive applications of plant antioxidant peptides, and look forward to their future development trends, which will provide a reference for further research and development of plant antioxidant peptides.