Search Results (148)

The extensive use of pesticides has significant implications for public health and the environment. Breeding crop plants is the most effective and environmentally friendly approach to improve the plants’ resistance. However, it is time-consuming and costly, and it is sometimes difficult to achieve satisfactory results. Plants induce defense responses to natural elicitors by interpreting multiple genes that encode proteins, including enzymes, secondary metabolites, and pathogenesis-related (PR) proteins. These responses characterize systemic acquired resistance. Humic substances trigger positive local and systemic physiological responses through a complex network of hormone-like signaling pathways and can be used to induce biotic and abiotic stress resistance. This study aimed to assess the effect of humic substances on the activity of phenylalanine ammonia-lyase (PAL), peroxidase (POX), and β-1,3-glucanase (GLU) used as a resistance marker in various plant species, including orange, coffee, sugarcane, soybeans, maize, and tomato. Seedlings were treated with a dilute aqueous suspension of humic substances (4 mM C L⁻¹) as a foliar spray or left untreated (control). Leaf tissues were collected for enzyme assessment two days later. Humic substances significantly promoted the systemic acquired resistance marker activities compared to the control in all independent assays. Overall, all enzymes studied in this work, PAL, GLUC, and POX, showed an increase in activity by 133%, 181%, and 149%, respectively. Among the crops studied, citrus and coffee achieved the highest activity increase in all enzymes, except for POX in coffee, which showed a decrease of 29% compared to the control. GLUC exhibited the highest response to HS treatment, the enzyme most prominently involved in increasing enzymatic activity in all crops. Plants can improve their resistance to pathogens through the exogenous application of HSs as this promotes the activity of enzymes related to plant resistance. Finally, we consider the potential use of humic substances as a natural chemical priming agent to boost plant resistance in agriculture Full article

Glutathione peroxidase (GPX) is crucial in mediating plant responses to abiotic stresses. In this study, bioinformatics methods were used to identify the GPX gene family in quinoa. A total of 15 CqGPX genes were identified at the quinoa genome level and conducted preliminary analysis on their protein characteristics, chromosome distribution, gene structure, conserved domain structure, cis-acting elements, and expression patterns. Phylogenetic analysis showed that the GPX genes of quinoa, Arabidopsis, soybean, rice, and maize were divided into three groups. Most of the CqGPXs had the three characteristic conserved motifs and other conserved sequences and amino acid residues. Six types of cis-acting elements were identified in the CqGPX gene promoter, with stress and hormone response-related cis-acting elements constituting the two main categories. Additionally, the expression patterns of CqGPX genes across various tissues and their responses to treatments with NaCl, PEG, CdCl₂, and H₂O₂ were also investigated. The qRT-PCR results showed significant differences in the expression levels of the CqGPX genes under stress treatment at different time points. Consistently, the activity of glutathione peroxidase enzymes increased under stresses. Heterologous expression of CqGPX4 and CqGPX15 conferred stress tolerance to E. coli. This study will provide a reference for exploring the function of CqGPX genes. Full article

Cadmium (Cd) is a highly toxic heavy metal that can greatly affect crops and pose a threat to food security. Plant growth-promoting rhizobacteria (PGPR) are capable of alleviating the harm of Cd to crops. In this research, a Cd-tolerant PGPR strain was isolated and screened from the root nodules of semi-wild soybeans. The strain was identified as Pseudomonas sp. strain KM25 by 16S rRNA. Strain KM25 has strong Cd tolerance and can produce indole-3-acetic acid (IAA) and siderophores, dissolve organic and inorganic phosphorus, and has 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Under Cd stress, all growth indicators of soybean seedlings were significantly inhibited. After inoculation with strain KM25, the heavy metal stress of soybeans was effectively alleviated. Compared with the non-inoculated group, its shoot height, shoot and root dry weight, fresh weight, and chlorophyll content were significantly increased. Strain KM25 increased the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities of soybean seedlings, reduced the malondialdehyde (MDA) content, increased the Cd content in the roots of soybeans, and decreased the Cd content in the shoot parts. In addition, inoculation treatment can affect the community structure of endophytic bacteria in the roots of soybeans under Cd stress, increasing the relative abundance of Proteobacteria, Bacteroidetes, Sphingomonas, Rhizobium, and Pseudomonas. This study demonstrates that strain KM25 is capable of significantly reducing the adverse effects of Cd on soybean plants while enhancing their growth. Full article

Human agricultural activities can impact the soil microbial ecosystem, but the future implications of such changes remain largely unknown. This study aimed to explore how soil microbes survive and reproduce under the pressure of human agricultural cultivation and whether they resist or adapt. A 10-year continuous experiment was conducted, planting a maize and soybean rotation (control group), alfalfa (legume), and wheat (poaceae) to study the impact of different crop planting on soil microbial communities. During the experiment, the physical and chemical properties of the soil samples were measured, and the rhizosphere microbial communities were analyzed. Different crop plantings had varying effects on soil microbial species diversity, but these differences were relatively limited. The relative abundance of Cyanobacteriales (order) was higher in wheat than in alfalfa. Moreover, Cyanobacteriales were positively correlated with soil peroxidase, thereby promoting wheat growth. In addition, nutrition for fungi is mainly derived from decaying straw and plant roots. This study divided soil microbes under agricultural cultivation conditions into three categories: adaptive microbes, neutral microbes, and resistant microbes. At the ecological level of plant rhizosphere microbes, the plant rhizosphere soil microbial community showed a coevolutionary relationship with human cultivation activities. Future research needs to pay more attention to the adaptability of soil microbial communities to agricultural cultivation and the potential impact of this adaptability on the global ecosystem. Full article

Soybean is one of the main agricultural commodities, and its productivity is limited by several diseases, such as anthracnose, which is caused by a complex of fungal species, with Colletotrichum truncatum being the most prevalent. Management is mainly carried out through chemical seed treatment. However, a reduction in the sensitivity of C. truncatum to fungicides was observed. Therefore, it is extremely important to search for products that are effective in controlling the disease. The objectives of this study were to evaluate the efficacy of commercial formulations of copper, potassium, manganese, and zinc phosphites in the treatment of soybean seeds infected by C. truncatum, as well as their direct fungitoxicity and ability to induce soybean defense mechanisms. For this purpose, seeds inoculated with C. truncatum were subjected to phosphites and a fungicide (carbendazim + thiram). The seeds were exposed to germination, health, and vigor tests. Fungal toxicity and the ability of phosphites to induce defense through the activities of catalase, peroxidase, and superoxide dismutase enzymes, as well as the levels of lignin and total soluble phenols, were also evaluated. Mn and Zn phosphites showed direct toxicity to C. truncatum and were as effective as the fungicide (carbendazim + thiram) in treating soybean seeds infected by the fungus. Mn phosphite induced the production of catalase (CAT), peroxidase (POX) and lignin, while Zn phosphite increased the production of CAT and POX. These results demonstrate the efficacy of Mn and Zn phosphites in controlling C. truncatum in infected soybean seeds, their direct toxic action, and their ability to induce resistance. Full article

In a previous Arabidopsis investigation, three ovule-specific cell-wall peroxidases decreased seed abortion rates. These peroxidases were expressed in soybean plants. Because cell wall peroxidases alter extensibility, possible effects on seed size and plant yield were evaluated. Since the effects of these peroxidases in Arabidopsis were dependent on environmental stress, soybean plants were grown in controlled environment greenhouse rooms under four temperature treatments; the daily temperature averages were 26, 30, 34, and 38 °C. In this experiment in vivo oxygen levels during seed growth were 25-fold below ambient, which could affect peroxidase activities. Consequently, soybeans were grown at atmospheric (21%) and elevated (32%) O₂ to evaluate peroxidase activities at higher O₂. Chambers were maintained at 700 ppm CO₂ in an attempt to minimize photorespiration in elevated O_2. Individual seed weight decreased with increasing temperature to zero at 38 °C. In elevated O₂ rooms, the oxygen concentration in developing seeds increased, but, due to leaf photorespiration, plant biomass and seed yield decreased. Seed size and shelling percentage declined equally with temperature at both O₂ concentrations. Expression of all three cell-wall peroxidases reduced seed abortion; however, that did not increase yields at ambient or elevated O₂. While O₂ concentration is less than 1% in developing seeds, increased O₂ levels in seeds were not beneficial for soybean reproduction. Full article

Pharmaceuticals are a class of emerging contaminants that have been widely detected in wastewater treatment facilities’ influent and effluent. They threaten the environment and non-target life. Thus, a promising treatment method, soybean peroxidase (SBP; EC 1.11.1.7), which catalyzes the oxidation of phenolic and anilino donors in the presence of hydrogen peroxide, was investigated as a treatment method. The aim was to remove two non-steroidal anti-inflammatory drugs, diclofenac (DCF) and aceclofenac (ACF), from synthetic wastewater via enzymatic oxidation, oligomerization, and precipitation. SBP can be extracted from soybean hulls, a byproduct of the soybean industry. DCF (0.10 mM) and ACF (0.10 mM) were amenable to SBP-catalyzed removal under the optimal operational parameters of pH 5 and 4; hydrogen peroxide: 0.40 and 0.45 mM; and minimum effective enzyme concentration: 0.15 and 0.60 U/mL, respectively. The initial first-order rate constant and half-life of each substrate were also determined under the established optimum conditions. Under these optimum conditions, the half-lives for DCF and ACF were 1.43 ± 0.01 and 0.84 ± 0.05 min, respectively. The results demonstrated that SBP is a robust enzyme that can achieve more than 95% removal for both compounds. Mass spectrometric analysis of the enzymatic treatment products of DCF revealed the formation of an oxidative tetramer. The SBP-catalyzed reaction is a highly effective method for removing DCF and ACF from synthetic wastewater, highlighting its potential for environmental cleanup of pharmaceutical contaminants. Full article

Ultraviolet B (UVB) radiation is a key factor contributing to photodamage in epidermal cells. This study investigated the protective effects of Thua Nao, a Thai fermented soybean product, against UVB-induced damage in human epidermal keratinocytes (HaCaT) and the underlying mechanisms. Thua Nao extract fractions were prepared using a solvent partition method. We found that the dichloromethane fraction (TN-DC), along with its isoflavones daidzein and glycitein, significantly protected against UVB-induced HaCaT cell death. This protection involved inhibiting caspase-9 and caspase-3 activation, thus preventing apoptosis. Additionally, treatment with TN-DC, daidzein, and glycitein suppressed the UVB-induced production of inflammatory mediators, including interleukin-6 (IL-6), IL-8, inducible nitric oxide synthase, and cyclooxygenase-2. These protective effects were associated with reduced intracellular reactive oxygen species and enhanced the levels of antioxidant enzymes, including superoxide dismutase and glutathione peroxidase 4. Signaling pathway analysis revealed that TN-DC activated the pro-survival ERK1/2 and Akt pathways while decreased the phosphorylation of JNK in UVB-exposed cells. On the other hand, daidzein and glycitein enhanced ERK1/2 activation and reduced the phosphorylation of JNK and p38 MAPKs. The involvement of ERK1/2 and Akt activation in cell survival was confirmed using specific inhibitors. Thus, TN-DC and its isoflavones protects keratinocytes from UVB-induced oxidative damage and inflammation by modulating MAPKs and Akt signaling. Full article

The role of a simulated microgravity environment on soybean growth was investigated. The root grew more under simulated microgravity conditions than in the presence of gravity. However, root shortening due to salt stress did not occur in simulated microgravity conditions. To reveal these mechanisms by simulated microgravity environment on soybean root, a proteomic analysis was conducted. Proteomic analysis revealed that among 1547 proteins, the abundances of proteins related to phytohormone, oxidative stress, ubiquitin/proteasome system, cell organization, and cell wall organization were altered under stimulated microgravity compared with gravity. Membrane-localized proteins and redox-related proteins were inversely correlated in protein numbers due to salt stress under gravity and the simulated microgravity condition. Proteins identified by proteomics were validated for protein accumulation by immunoblot analysis. Superoxide dismutase and ascorbate peroxidases, which are reactive oxygen species-scavenging proteins, increased in soybean root under salt stress but not in the simulated microgravity conditions even under stress. The accumulation of 45 kDa aquaporin and 70 kDa calnexin in soybean root under salt stress were increased in the simulated microgravity conditions compared to gravity. These findings suggest that soybean growth under salt stress may be regulated through improved water permeability, mitigation of reactive oxygen species production, and restoration of protein folding under simulated microgravity conditions. Full article

Cadmium (Cd) is a toxic, non-essential heavy metal, with significant stress to plants such as soybean (Glycine max). High Cd concentration in the soil inhibits various stages of soybean growth, including seed germination, vegetative growth, and the reproduction stage. Phosphate, a vital macronutrient, has been shown to alleviate Cd-induced stress; however, the molecular mechanisms remain poorly understood. This study aimed to explore the interactive effects of Cd and phosphate on soybeans at the physiological, transcriptomic, and metabolic levels using a multi-omics approach. Experiments were conducted where soybean plants were treated with different concentrations of Cd and phosphate. The results indicated that Cd stress significantly reduced plant height, photosynthetic rate, and transpiration rate, while phosphorus application mitigated these effects, reducing Cd absorption in both roots and shoots. Furthermore, antioxidant enzyme activities (superoxide dismutase, catalase, and peroxidase) were significantly enhanced by phosphate under Cd stress, which scavenged reactive oxygen species (ROS) generated by cadmium, thereby protecting cells from oxidative stress damage. Transcriptome and metabolome analyses revealed substantial changes in gene expression and metabolite profiles in response to Cd and phosphate treatments. Notably, phosphorus treatment induced the up-regulation of genes involved in stress response, root development, and metal transport, while altering metabolic pathways related to phenolic acids, flavonoids, and lipids. This research provided new insights into the molecular mechanism by which phosphorus enhanced the activity of antioxidant enzymes, thereby improving the plant’s antioxidant defense capacity and reducing the toxic effects of cadmium in soybeans, offering potential strategies for enhancing crop resilience against heavy metal contamination. Full article

Zanthoxylum planispinum var. Dingtanensis (hereafter Z. planispinum) has excellent characteristics, including Ca and drought tolerance. It can flourish in stony soils, and it is used as a pioneer plant in karst rocky desertification control. However, soil degradation, coupled with the removal of nutrients absorbed from the soil by Z. planispinum’s fruit harvesting, exacerbates nutrient deficiency. The effects of fertilization on soil nutrient utilization and microbial limiting factors remain unclear. Here, we established a long-term (3 year) field experiment of no fertilization (CK), organic fertilizer + chemical fertilizer + sprinkler irrigation (T1), chemical fertilizer + sprinkler irrigation (T2), chemical fertilizer treatment (T3), and leguminous (soybean) + chemical fertilizer + sprinkler irrigation (T4). Our findings indicate that fertilization significantly improved the nutrient uptake efficiency of Z. planispinum, and it also enhanced urease activity compared with CK. T1 increased soil respiration and improved water transport, and the soil nutrient content retained in T1 was relatively high. It delayed the mineralization rate of organic matter, promoted nutrient balance, and enhanced enzyme activity related to the carbon and nitrogen cycle. T4 caused soil acidification, reducing the activity of peroxidase (POD) and polyphenol oxidase (PPO). The soil microbial community in the Z. planispinum plantation was limited by carbon and phosphorus, and T1 mitigated this limitation. This study indicated that soil nutrient content regulated enzymatic activity by influencing microbial resource limitation, with organic carbon being the dominant factor. Overall, we recommend T1 as the optimal fertilization strategy for Z. planispinum plantations. Full article

Corn (Zea mays L.) productivity is often compromised by phytosanitary challenges, with fungal disease like Curvularia leaf spot being particularly significant. While synthetic fungicides are commonly used, there is growing interest in exploring alternative compounds that are effective against pathogens, ensure food safety, and have low toxicity to non-target organisms. In this study, we examined the biochemical changes in corn plants treated with Lippia sidoides essential oil and its major compound, thymol. Both treatments serve as preventive measures for inoculated plants and induced resistance. We tested five concentrations of each product in in vivo experiments. After evaluating the area under the disease progress curve, we analyzed leaf samples for enzymatic activities, including superoxide dismutase, catalase, ascorbate peroxidase, and chitinase. Phytoalexin induction was assessed using soybean cotyledons and sorghum mesocotyls. Cytotoxicity tests revealed lower toxicity at concentrations below 50 µL/mL. Both essential oil and thymol stimulated the production of reactive oxygen species, with thymol primarily activating catalase and L. sidoides oil increasing ascorbate peroxidase levels. Both thymol and L. sidoides were also key activators of chitinase. These findings suggest that L. sidoides essential oil and thymol are promising candidates for developing biological control products to enhance plant defense against pathogens. Full article

Phytophagous mites are herbivores that feed on various economically important plants, such as soybean [Glycine max (L.) Merril]. Thus, our objective is to evaluate the oxidative stress stage of soybean plants infested by Tetranychus ludeni Zacher. Leaflets from three trifoliate leaves were pooled to form composite samples for each exposure time and evaluated at the following evaluation times: 0 h, 20 min, 6 h, 12 h, 24 h, and 48 h. In the initial phase of infestation (20 min), an oxidative burst was observed, represented by prominent hydrogen peroxide accumulation rather than superoxide radicals. This oxidative burst occurred in parallel to a strong increase in the antioxidant activities of catalase, ascorbate peroxidase, and glutathione S-transferase, but not in that of superoxide dismutase. These changes likely reflected an enhanced activation of signaling pathways involved in the oxidative stress response. After this initial phase, from 20 min to 6 h, a prominent decrease occurred in catalase, ascorbate peroxidase, and glutathione S-transferases activities, despite the hydrogen peroxide levels remaining significantly elevated, along with a marked but transient increase in the reduced glutathione content and proline. Interestingly, superoxide dismutase activity increased significantly after 6 h in parallel to lipid peroxidation, whereas the content of hydrogen peroxide remained elevated until 12 h of infestation. By the final evaluation, after 48 h of infestation, some redox indicators remained altered in relation to control plants, but in a state of moderate redox stress. Thus, in an unprecedented way, our data suggest that T. ludeni infestation triggered a moderate oxidative stress response in soybean plants. These findings highlight that proper monitoring and management can reduce economic losses without resorting to aggressive chemical interventions. Full article

Peanut is a key cash crop worldwide, yet the limited availability of functional genes and markers for breeding hinders further progress, largely due to the lack of an efficient and user-friendly transformation system. This study aimed to comprehensively evaluate the effectiveness of nodal agroinjection, a novel transformation technique we developed for peanut, by introducing the soybean cold-tolerance gene SCTF-1. Putative transgenic seeds and seedlings were screened using genomic DNA PCR, while transgene expression was analyzed via qRT-PCR and phenotypic assessments. Southern blotting confirmed the stable integration of SCTF-1. The transgenic seedlings displayed enhanced chilling tolerance, characterized by increased proline accumulation, reduced malondialdehyde (MDA), and elevated peroxidase (POD) activity. These findings demonstrate that nodal agroinjection is an efficient and reliable approach for generating transgenic peanut and analyzing gene function. This method offers a promising alternative to conventional tissue culture-based transformation strategies. Full article

Salinity stress poses a major obstacle to agricultural productivity. Employing plant growth-promoting rhizobacteria (PGPR) has attracted significant attention due to its potential to improve plant development in challenging conditions. Yet, additional investigation is essential to fully understand the potential of PGPR in mitigating salinity stress, especially in field applications. Hence, this study investigated the resistance mechanisms of soybean (Glycine max (L.) Merr.) under salt stress with PGPR application through a field experiment with four treatments: normal soybean planting (NN), normal planting + PGPR (NP), salt stress planting (SN), and salt stress planting + PGPR (SP). This research investigated how applying PGPR under salt stress influences soybean photosynthetic traits, osmotic regulation, rhizosphere microbial communities, and yield quality. The results demonstrated that salt stress enhanced leaf temperature and significantly reduced the leaf area index, SPAD value, stomatal conductance, photosynthetic rate, and transpiration rate of soybeans. Compared to SN treatment, SP treatment significantly improved the stomatal conductance, photosynthetic rate, and transpiration rate by 10.98%, 16.28%, and 35.59%, respectively. Salt stress substantially increased sodium (Na⁺) concentration and Na⁺/K⁺ ratio in leaves, roots, and grains while reducing potassium (K⁺) concentration in roots and leaves. Under salinity stress, PGPR application significantly minimized Na⁺ concentration in leaves and enhanced K⁺ concentration in leaves, roots, and grains by 47.05%, 25.72%, and 14.48%, respectively. PGPR application boosted carbon assimilation (starch synthesis) by enhancing the activities of sucrose synthase, fructokinase, and ADP-glucose pyrophosphorylase. It improved physiological parameters and increased soybean yield by 32.57% compared to SN treatment. Additionally, PGPR enhanced antioxidant enzyme activities, including glutathione reductase, peroxidase, ascorbate peroxidase, and monodehydroascorbate reductase, reducing oxidative damage from salt stress. Analysis of rhizosphere microbial communities revealed that PGPR application enriched beneficial bacterial phyla such as Bacteroidetes, Firmicutes, Nitrospirae, and Patescibacteria and fungal genera like Metarhizium. These microbial shifts likely contributed to improved nutrient cycling and plant–microbe interactions, further enhancing soybean resilience to salinity. This study demonstrates that PGPR enhances soybean growth, microbial diversity, and salt tolerance under salinity stress, while future efforts should optimize formulations, explore synergies, and scale up for sustainable productivity. Full article