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.

Here, we investigate how the oxidation state of Cr adsorbed to solid surfaces can change during XPS analysis. Experiments are performed to test how Fe(III) solid surfaces, aqueous chemistry, and XPS vacuum conditions affected the measured Cr oxidation state. While oxidized Cr(VI) adsorbs onto nonreducing solid surfaces in the experiments, reduced Cr(III) is primarily measured by XPS. The reduction of adsorbed Cr(VI) occurs under the vacuum conditions of the XPS as CO2, O-2, and H2O are removed from the sample surface. These results suggest that Fe(III) solid surfaces exposed to high-vacuum conditions and/or X-rays can cause the reduction of Cr or other elements with a high redox potential contained on that surface.

Soil salinization is increasingly recognized as a critical environmental challenge that significantly threatens plant survival and agricultural productivity. To elucidate the mechanism of salt resistance in poplar, physiological and transcriptomic analyses were conducted on 84K poplar (Populus alba x Populus glandulosa) under varying salt concentrations (0, 100, 200 and 300 mM NaCl). As salt levels increased, observable damage to poplar progressively intensified. Differentially expressed genes under salt stress were primarily enriched in photosynthesis, redox activity and glutathione metabolism pathways. Salt stress reduced chlorophyll content and net photosynthetic rate, accompanied by the downregulation of photosynthesis-related genes. NaCl (300 mM) significantly inhibited the photochemical activity of photosystems. The higher photochemical activity under 100 and 200 mM NaCl was attributed to the activated PGR5-cyclic electron flow photoprotective mechanism. However, the NAD(P)H dehydrogenase-like (NDH)-cyclic electron flow was inhibited under all salt levels. Salt stress led to reactive oxygen species accumulation, activating the ASA-GSH cycle and antioxidant enzymes to mitigate oxidative damage. Weighted gene co-expression network analysis showed that five photosynthesis-related hub genes (e.g., FNR and TPI) were down-regulated and nine antioxidant-related hub genes (e.g., GRX, GPX and GST) were up-regulated under salt stress conditions. PagGRXC9 encodes glutaredoxin and was found to be differentially expressed during the salt stress condition. Functional studies showed that overexpressing PagGRXC9 enhanced salt tolerance in yeast, and in poplar, it improved growth, FV/FM, non-photochemical quenching values and resistance to H2O2-induced oxidative stress under salt stress. This study constructed the photosynthetic and antioxidant response network for salt stress in poplar, revealing that PagGRXC9 enhances salt tolerance by reducing photoinhibition and increasing antioxidant capacity. These findings provide valuable insights for breeding salt-tolerant forest trees.

Anthropogenic activities enhance the concentration of trace elements in environment like highly carcinogenic Cadmium (Cd), which adversely affect the plant growth and development. They deliberately accumulate defense compounds e.g., flavonoids, terpenoids, and alkaloids to ensure resilience in such adverse conditions. Current study explores the adaptive evolution, structural complexity, and functional roles of Flavin Adenine Dinucleotide (FAD)-linked oxidase genes in widespread leading cash crop cotton. As a non-edible, hyperaccumulator halophyte crop, cotton is an excellent candidate for phytoremediation of Cd-polluted soils by manipulating stress resistant genetic material. They utilize FAD as a cofactor to drive oxidative reactions, including benzylisoquinoline alkaloid biosynthesis, which plays a critical role in cellular signaling pathways, stress responses and metabolic processes. A total of 387 FADs retrieved from four cotton species were distributed into seven families and twelve subfamilies. They underwent large scale expansion under intense purifying selection with lineagespecific gene loss and retention, reflecting their ongoing evolution for functional advancements to adopt altering environment. High throughput transcriptomic, functional enrichment and qRT-PCR validation revealed their multifaceted roles in growth, development and stress responses. Overexpression of GhBBE59 (BBE7) in Arabidopsis enhanced Cd tolerance by 25 % marked by a 20% reduction in malondiadehyde (MDA) and 25 % higher superoxide dismutase (SOD) activity compared to wild type plants. While its knockdown in cotton, reduced Proline accumulation by 60 % and increased electrolyte leakage by 2 fold, rendering plants hypersensitity to Cd stress. Transcriptomic and biochemical analyses demonstrated that BBE7 modulates redox homeostasis via 25% higher glutathione accumulation and hormonal crosstalk, mitigating oxidative damage. Functional analyses further revealed the pivotal role of BBE7 in regulation of oxidative stress, antioxidant production, epigenetic modifications and proline accumulation, thereby enhancing stress resilience. These findings hold substantial promise for reducing cadmium accumulation in soils, thereby mitigating its entry into the food chain and associated health risks. The implications of current study extend beyond fundamental research, addressing real-world challenges associated with environmental stresses and sustainable agriculture practices by enabling safer cultivation in polluted environments.

Contamination of vegetables with heavy metals and microplastics is a major environmental and human health concern. This study investigated the role of taurine (TAE) in alleviating arsenic (As) and polyvinyl chloride microplastic (MP) toxicity in broccoli plants. The experiment followed a completely randomized design with four replicates per treatment. Plants were grown in soil spiked with MP (200 mg kg-1), As (42.8 mg kg-1), and their combination (As + MP) with or without taurine (TAE; 100 mg L-1) foliar supplementation. Results demonstrated that MP, As, and As + MP toxicity markedly decreased growth, chlorophyll content, photosynthesis, and nutrient uptake in broccoli plants. Exposure to individual or combined MP and As increased oxidative damage, indicated by elevated methylglyoxal (MG), superoxide radical (O2 & sdot;-), hydrogen peroxide (H2O2), hydroxyl radical (& sdot;OH), and malondialdehyde (MDA) levels alongside intensified lipoxygenase (LOX) activity and leaf relative membrane permeability (RMP). Histochemical analyses revealed higher lipid peroxidation, membrane damage as well as increased H2O2 and O2 center dot- levels in the leaves of stressed plants. Micropalstic and As toxicity deteriorated anatomical structures, with diminished leaf and root epidermal thickness, cortex thickness, and vascular bundle area. However, TAE improved the antioxidant enzyme activities, endogenous ascorbate-glutathione pools, hydrogen sulfide and nitric oxide levels that reduced H2O2, O2 & sdot;-, & sdot;OH, RMP, MDA, and activity of LOX. Taurine elevated osmolyte accumulation that protected membrane integrity, resulting in increased leaf relative water content and plant biomass. Plants supplemented with TAE demonstrated improved anatomical structures, resulting in diminished As uptake and its associated phytotoxicity. These findings highlight that TAE improved redox balance, osmoregulation, ion homeostasis, and anatomical structures, augmenting tolerance to As and MP toxicity in broccoli.

Ferromanganese nodules (FMNs), simultaneously termed as manganese nodules, are metallic concretions typically found in the B horizon of iron and manganese-rich soils. These nodules are primarily formed through the biomineralization process driven by favorable redox reactions and microbial activity. The formation of FMNs in the soil is governed by complex geochemical interactions and influenced by both biotic and abiotic factors, such as temperature, pH, organic matter, redox potential (Eh), wet/dry cycles, and nucleation sites. FMNs typically vary in size, ranging from a few microns to several centimeters, and exhibit diverse shapes, from spherical to irregular. These nodules play a crucial role in nutrient cycling and the adsorption of heavy metals, including phosphorus, lead, copper, zinc, cobalt, and nickel, thereby improving soil quality and preventing metal leaching into aquatic environments. The ion exchange during redox reactions, complexation, occlusion, and adsorption are the key mechanisms through which heavy metals can become immobilized in soil FMNs. The formation of FMNs involves Mn-oxidizing bacteria, such as Bacillus, Pedomicrobium, Erythrobacter, Pseudomonas putida, Geobacter, and Leptothrix discophora, which use specific functional genes such as mnxG, moxA, mopA, CumA, ombB, omaB, OmcB, and mofA to facilitate manganese oxidation. This process reacts with geological material, resulting in the precipitation of metal leachates and the development of metal oxide coatings that serve as nucleation sites for FMNs. Such microbial activities are not only essential for FMNs formation but also for trapping heavy metals in soil, highlighting their importance in soil biogeochemical cycling and ecological functions. However, further research is needed to unravel the complex biogeochemical interactions that influence FMNs growth and composition, as well as to understand the stabilization and release dynamics of nutrients and heavy metals, and the roles of microbial communities and functional genes involved in these processes, particularly in relation to soil fertility and plant nutrition.

Cadmium (Cd) stress constitutes a significant issue in agricultural soil, inflicts lethal damages to plants and posing a serious risk to public health as it enters the food chain. This review addresses the cause of Cd toxicity, its numerous forms and absorption mechanism via various transporters and their detrimental impacts on plants. At high level, Cd interacts with cellular molecules leading to overproduction of reactive oxygen species. Under Cd stress, plants naturally synthesize various compatible solutes to enhance the plant's stress tolerance and glycine betaine (GB) is one of such solutes which act as osmoprotectant in plants. The Cd causes oxidative damage to the cells, resulted in changes in morphological attributes, physiological processes etc. and it is indispensable to alleviate Cd toxicity. To mitigate the harmful impacts of Cd, plants adapt self-regulating tolerance mechanism by producing naturally occurring osmolytes and phytochelatins (PCs). Biosynthetic pathway of GB and GB-mediated tolerance mechanism via redox homeostasis, osmotic adjustment, and mechanism of compartmentalization of Cd into the vacuole, the role of genetic engineering in GB biosynthesis in crop plants through which plants can improve their stress tolerance have been discussed. Amalgamation of this strategy must be implemented in the market with synchronization of farmers into cooperatives. This will be beneficial for the improvement in soil, plant and human health alongwith the reduction of Cd toxicity in environment. Further, this strategy must be used by government and non-government agencies, which is the most economical approach to apply at the farmer level.

BackgroundYellow lupine (Lupinus luteus L.) is a high-protein crop of considerable economic and ecological significance. It has the ability to fix atmospheric nitrogen in symbiosis with Rhizobium, enriching marginal soils with this essential nutrient and reducing the need for artificial fertilizers. Additionally, lupine produces seeds with a high protein content, making it valuable for animal feed production. However, drought negatively affects lupine development, its mutualistic relationship with bacteria, and overall yield. To understand how lupine responds to this stress, global transcriptome sequencing was conducted, along with in-depth biochemical, chromatography, and microscopy analyses of roots subjected to drought. The results presented here contribute to strategies aimed at mitigating the effects of water deficit on lupine growth and development.ResultsBased on RNA-seq, drought-specific genes were identified and annotated to biological pathways involved in phytohormone biosynthesis/signaling, lipid metabolism, and redox homeostasis. Our findings indicate that drought-induced disruption of redox balance characterized by the upregulation of reactive oxygen species (ROS) scavenging enzymes, coincided with the accumulation of lipid-metabolizing enzymes, such as phospholipase D (PLD) and lipoxygenase (LOX). This disruption also led to modifications in lipid homeostasis, including increased levels of triacylglycerols (TAG) and free fatty acids (FFA), along with a decrease in polar lipid content. Additionally, the stress response involved alterations in the transcriptional regulation of the linolenic acid metabolism network, resulting in changes in the composition of fatty acids containing 18 carbons.ConclusionThe first comprehensive global transcriptomic profiles of lupine roots, combined with the identification of key stress-responsive molecules, represent a significant advancement in understanding lupine's responses to abiotic stress. The increased expression of the Delta 12DESATURASE gene and enhanced PLD activity lead to higher level of linoleic acid (18:2), which is subsequently oxidized by LOX, resulting in membrane damage and malondialdehyde (MDA) accumulation. Oxidative stress elevates the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), while the conversion of FFAs into TAGs provides protection against ROS. This research offers valuable molecular and biochemical candidates with significant potential to enhance drought tolerance . It enables innovative strategies in lupine breeding and crop improvement to address critical agricultural challenges.

Conventional tomato production is widely threatened by environmental changes that impose increasingly frequent and severe conditions of soil salinization and water shortage. The assessment of the wild germplasm has become an appealing strategy for the stress-resilience improvement of crops. Tomato interspecific diversity encompasses wild species that are native to the dry shores and high-elevated deserts of the Andean countries, often thriving under circumstances of drought and salinity. The present work aimed to compare the effects of moderate salinity stress under different watering regimes on the ion distribution, redox homeostasis, osmoregulation, and antioxidant defenses between a domestic cultivar of tomato (Chico III) and the wild tomato species Solanum galapagense (LA1403), Solanum habrochaites (LA1223), and Solanum neorickii (LA2194). Results showed that although wild tomato plants grew slower than the cultivar, their growth was less affected by exposure to salt or to lower water availability. S. galapagense revealed a Na+ includer behavior under salt stress, increasing Na+ levels by 6-fold over control, reaching levels 4 times higher than in the cultivar. Nonetheless, H2O2-detoxifying enzymes were activated, and shoot elongation was sustained in this species, suggesting an efficient Na+ compartmentalization. On the other hand, the domestic cultivar had the highest accumulation of Na+ in roots and showed the lowest ability to sustain growth under combined stress. Leaves of S. habrochaites showed a huge proline buildup under salt stress, whereas S. neorickii and S. galapagense seemed to prevent proline accumulation. S. habrochaites also had high levels of antioxidant metabolites and superoxide dismutase activity under control conditions but downregulated further antioxidant defenses in response to stress exposure. No oxidative damages were noticed despite the almost 2-fold increase in ROS content in the leaves of S. neorickii under salt stress, which showed a negative correlation with growth traits, but an improvement in the antioxidant potential. A principal component analysis (PCA) revealed five PCs with eigenvalues >1, explaining 84 % of the total variability, and suggesting a separation of the evaluated samples mainly in accordance with the type of redox disturbances and antioxidant defenses employed, levels of photosynthetic pigments, balance between Na+ and K+ uptake and proline accumulation. These findings show that wild tomato plants respond differently than cultivated ones under moderate salinity and reduced water availability, suggesting interesting osmoregulatory and antioxidant mechanisms in S. galapagense and S. habrochaites.

Spikelet degeneration is a critical physiological issue that limits grain yield in rice (Oryza sativa L.), influenced by soil moisture conditions during meiosis. The study aimed to investigate the role and mechanism of moderate soil drying in spikelet degeneration and grain yield, as well as to establish a strategy and irrigation regime for suppressing spikelet degeneration to increase grain yield in rice. Field experiments were conducted involving two irrigation regimes: conventional well-watered (C-WW) and moderate soil drying (M-SD) during meiosis. Transgenic rice lines and chemical regulators were employed to elucidate the underlying partial biological mechanisms of this process. The results showed that M-SD regime effectively reduced spikelet degeneration rate and increased grain yield compared to C-WW. This improvement under M-SD regime was primarily attributed to the enhanced proline and aquaporin-mediated osmotic balance and redox homeostasis in young rice panicles, as well as the increased root activity during meiosis. The increased levels of brassinosteroids (BRs) and decreased levels of ethylene (ETH) in young panicles under the M-SD were closely associated with the enhanced proline and aquaporin-mediated osmotic balance and redox homeostasis, decreased oxidative damage, and reduced spikelet degeneration rate. The intrinsic relationship among key aquaporin genes expression and proline levels, osmotic balance and redox homeostasis, spikelet degeneration rate, as well as BRs and ETH levels, was further confirmed through the use of transgenic rice lines and chemical regulators. Collectively, an M-SD regime during meiosis can effectively suppress spikelet degeneration and thereby enhance grain yield, primarily through well-maintained osmotic balance and redox homeostasis in rice.