Researchers have tried hard to study the toxic effects of single pollutants like certain antibiotics and nanoplastic particles on plants. But we still know little about how these pollutants interact when they're together in the environment, and what combined toxic effects they have on plants. This study assessed the toxic effects of polystyrene nanoplastics (PS-NPs) and ciprofloxacin (CIP), both individually and in combination, on soybean (Glycine max L.) seedlings by various concentration gradients treatments of PS-NPs (0, 10, 100 mg/L) and CIP (0, 10 mg/L). The results indicated that high concentrations of PS-NPs significantly impeded soybean seedling growth, as evidenced by reductions in root length, plant height, and leaf area. CIP predominantly affected the physiological functions of leaves, resulting in a decrease in chlorophyll content. The combined exposure demonstrated synergistic effects, further intensifying the adverse impacts on the growth and physiological functions of soybean seedlings. Metabolomic analyses indicated that single and combined exposures markedly altered the metabolite expression profiles in soybean leaves, particularly related to amino acid and antioxidant defense metabolic pathways. These results indicate the comprehensive effects of NPs with antibiotics on plants and provide novel insights into toxic mechanisms.

BackgroundSoybean (Glycine max L. Merrill), a vital source of edible oil and protein, ranks seventh in global agricultural production, yet its productivity is significantly hindered by potential toxic metal/liods (PTM) stress. Arsenic (As), a highly toxic soil contaminant, poses substantial risks to both plants and humans, even at trace concentrations, particularly in China.ResultsThis research endeavor delves into the combined effect of arsenate (AsV), a common form of As in soil, and nano-selenium (nSe), on the transcriptional regulation of key genes and the modulation of signaling and metabolic cascades in young soybean seedlings. Our findings indicate that nSe mitigates AsV toxicity by modulating hormonal signaling cascades, particularly the phenylalanine and salicylic acid pathways, thereby augmenting antioxidant defenses and mitigating the damaging effects of reactive oxygen species (ROS) on soybean roots.ConclusionThis study offers valuable insights into the molecular mechanisms underlying metalloid tolerance in soybean, opening avenues for the development of strategies to bolster As resistance in contaminated soils. Nevertheless, further investigation is imperative to elucidate the intricate interplay of hormonal signaling in soybean roots during nSe supplementation under As stress conditions.

The green-belly stink bug is an early pest in the second crop of corn, following soybean. The dynamics of infestations by this pest in systems where corn is defoliated in the early stages is still unknown. Therefore, the objective was to evaluate the feeding of the stink bug on corn subjected to early defoliation. In a greenhouse, used a 2 x 4 factorial design, with two cultivars: BRS3042 VTPRO2 and 1F640PRO2, and four treatments: Without stink bug and with plant cutting (WSB-C); With stink bug before cutting (SB-BC); With stink bug after cutting (SB-AC); With stink bug and without cutting (SB-WC), with ten repetitions. Cutting of the plants was performed at the V3 stage, at a height of five centimeters above the soil. Infestation with stink bugs was carried out five days after emergence and/or after cutting, with two stink bugs per pot. The following were evaluated: injury score, height, stem diameter, fresh and dry plant weight. The plants that were not cut (SB-WC) presented the highest values in height and diameter, resulting in injury scores around 1 compared to those that were infested after the cut (SB-AC), which had scores varying between 3 and 4 and had smaller height and diameter. It was concluded that removing the leaf surface impairs the establishment of the corn plant, and with the infestation of the green-belly stink bug, the severity of the damage increases.

Green soybean (edamame), an early-harvested soybean, is a popular vegetable in Asia and is recognised as a healthy vegetable in the other parts of the world. In Japan, edamame yield has gradually decreased over the last 30 years, despite similar cultivation areas. Damage caused by the soybean cyst nematode (SCN), Heterodera glycines, is one of the main causes. We surveyed the distribution of SCN in different locations and found a wide distribution of SCN across Japan. Different control measures are available, such as chemical control using fumigants or a granular type of nematicide, solarisation, and rotation with non-host crops. We are developing a new type of biological control method, which comprises short-term field cultivation and soil incorporation of mung bean. This method not only decreases the SCN density in soil but also mitigates soil erosion and nitrate leaching. For future SCN control it is essential to establish an environmentally friendly management strategy.

Phytophthora root and stem rot is a disease caused by the oomycete Phytophthora sojae that can lead to severe damage in soybean. Disease management involves the use of resistant soybean varieties, which can have either complete resistance through Rps genes or partial resistance. The pathogen population has rapid evolution and constant changes in pathogenicity, thus, new pathotypes of the pathogen capable of overcoming Rps genes are frequently reported. In addition to genetic resistance, other control methods of Phytophthora root and stem rot of soybean include seed treatment with oomycides/fungicides, use of biological and alternative products, and cultural practices that promote soil drainage and avoid compaction. This review provides detailed and up-to-date information on P. sojae, its interaction with soybean, the diversity of the pathogen population, and control methods of Phytophthora root and stem rot focused on host genetic resistance.

Rotylenchulus reniformis poses a significant threat to cotton crops in the Brazilian Cerrado, particularly when grown consecutively with soybeans. This nematode has not only become a concern for cotton but has also led to considerable damage in soybean crops, emphasizing the need for effective nematode control in both agricultural settings. The aim of this study was to combine genetic control with the application of biological nematicides, as seed treatment, to manage R. reniformis under greenhouse conditions. Two soybean cultivars, TMG 4182 and Fibra, resistant and susceptible, were used and the biological nematicides used included Purpureocillium lilacinum, Trichoderma harzianum + T. asperellum + Bacillus amyloliquefaciens, B. subtilis + B. licheniformis, and B. firmus. Inoculation with 800 R. reniformis occurred in the cotyledonary stage, with evaluations conducted at 72 and 76 days after inoculation for Experiments 1 and 2, respectively. Nematodes were extracted from the soil and roots, calculating the reproduction factor (RF). The combination of biological nematicides with resistant cultivars did not yield substantial benefits in controlling reniform nematodes in soybean but safeguarding resistant cultivars through the application of chemical or biological nematicides is important to mitigate inoculum pressure on resistance genes. In addition, biological nematicides evaluated in this study did not improve soybean plant development and we concluded that managing reniform nematodes in soybean necessitates the integration of diverse control measures to effectively address the challenges posed by this nematode's impact on crops.

Myochrous armatus Baly, 1865 (Coleoptera: Chrysomelidae) has expanded its occurrence significantly into soybean-growing areas of Brazilian Cerrado and became an important early-season soil pest. Experiments were performed under field conditions from 2020 to 2023 to assess several aspects: (1) population behaviour over crop season and offseason; (2) day/night behaviour during the early stages of soybean plants and (3) injury to plants and potential damage to soybean yield to establish the Economic Injury Level (EIL). Adults of the M. armatus population presented a season-long abundance during the specific period from late October to January, with major captures in November and December (end of Spring), either inside or on the edge of soybean fields. Weeds and volunteer plants of corn and cotton hosts adults and eggs. These findings suggest an univoltine life cycle. Behavioural assessments revealed that M. armatus does not exhibit a specific day, night or crepuscular behaviour, performing deeds at any time. The majority of insects (40% to 70%) were found in the soil throughout the day and night. Adults feed on soybean plants by scraping or cutting the stem, cotyledon, petiole and apical sprouting. Their preference is initially for the stem and cotyledon (up to 14 days after emergence), and later for the petiole (after 21 days of emergence). After 7 days of coexistence at V1-V3 soybean stages, we observed a potential yield reduction of 35% for each insect per plant. Dynamic EIL estimations are between 0.4 and 1.9 adults per row metre, depending on the grower productivity expectation, control costs and soybean market value. Our results are fundamental for establishing Integrated Pest Management for M. armatus in soybean and other crop systems.

Soybean is the main oilseed cultivated worldwide. Even though Brazil is the world's largest producer and exporter of soybean, its production is severely limited by biotic factors. Soil borne diseases are the most damaging biotic stressors since they significantly reduce yield and are challenging to manage. In this context, the present study aimed to evaluate the potential of a bacterial strain (Ag109) as a biocontrol agent for different soil pathogens (nematodes and fungi) of soybean. In addition, the genome of Ag109 was wholly sequenced and genes related to secondary metabolite production and plant growth promotion were mined. Ag109 showed nematode control in soybean and controlled 69 and 45% of the populations of Meloidogyne javanica and Pratylenchus brachyurus, respectively. Regarding antifungal activity, these strains showed activity against Macrophomia phaseolina, Rhizoctonia solani, and Sclerotinia sclerotiorum. For S. sclerotiorum, this strain increased the number of healthy plants and root dry mass compared to the control (with inoculation). Based on the average nucleotide identity and digital DNA-DNA hybridization, this strain was identified as Bacillus velezensis. Diverse clusters of specific genes related to secondary metabolite biosynthesis and root growth promotion were identified, highlighting the potential of this strain to be used as a multifunctional microbial inoculant that acts as a biological control agent while promoting plant growth in soybean.

Methyl jasmonate (MeJA) is a phytohormone involved in plant defense against stress. However, its application as pretreatment in soybean seeds is limited. Here, we investigated whether seed pretreatment with MeJA mitigated the negative effects of water restriction (WR) and mechanical wounding (MW) in soybean seedlings at the V1 vegetative stage. Seeds of Glycine max (Monsoy 6410 variety) were pretreated with water or 12.5 mu M MeJA for 14 h. The obtained seedlings were transferred to pots containing substrate (soil and sand) kept in a greenhouse and subjected to different growth conditions: control (no stress), WR (40% water retention), and MW. The experiment was conducted in a 2 x 3 factorial scheme (2 seed pretreatments x 3 growth conditions). The variables analyzed were ethylene levels, hydrogen peroxide, lipid peroxidation, antioxidant system enzymes, sugars, amino acids, proteins, proline, and growth (root and shoot length). WR negatively affected seedling growth, regardless of seed pretreatment, but proline levels increased with MeJA application. In seedlings subjected to MW, MeJA increased ethylene release, which was related to reduced damage. It suggests that pretreatment of soybean seeds with MeJA is a promising tool to mitigate the deleterious effects of biotic and abiotic stresses during seedling establishment, inducing distinct tolerance strategies.

Soil salinization negatively affects the growth and yield of economically valuable crops such as soybeans. New technologies are being developed to minimize the damage caused by saline stress and improve crop performance. Therefore, the use of biostimulants in agriculture may offer an alternative method to mitigate the deleterious effects of salinity. Extracts of the seaweed,Ascophyllum nodosum and humic substances (fulvic acids) are commonly used. Therefore, this study aimed to evaluate the action of a biostimulant composed of A. nodosum seaweed extract and fulvic acid applied at different phenological stages on the biometric, biochemical, and physiological parameters of soybeans (Glycine max) subjected to irrigation with saline water. The experimental design used was completely randomized in a 3 x 2 + 2 factorial scheme, referring to three applications of the biostimulant at different soybean phenological stages: V3, V3R1, and V3R1R4, two levels of electrical conductivity of irrigation water (ECw): 0.5 (S0) and 5.0 dS m-1 (S1), two additional controls, one with a positive control (PC) and the other with a negative control (NC). The experiment had five replicates with one plant per plot. The results of this study suggest that the application of the biostimulant can mitigate the harmful effects of salt stress in soybeans. The results obtained with V3R1 application in the parameters stem diameter, leaf area, shoot dry mass, electrolyte leakage, and chlorophyll b represent greater efficiency in mitigating the harmful effects of salinity in soybean cultivation.