Effects of arbuscular mycorrhizal fungi on frond antimony enrichment, morphology, and proteomics in Pteris cretica var. nervosa during antimony phytoremediation

Recent Advances in Transcriptome Analysis Within the Realm of Low Arsenic Rice Breeding

Arsenic (As), a toxic element, is widely distributed in soil and irrigation water. Rice (Oryza sativa L.), the staple food in Southern China, exhibits a greater propensity for As uptake compared to other crops. Arsenic pollution in paddy fields not only impairs rice growth but also poses a serious threat to food security and human health. Nevertheless, the molecular mechanism underlying the response to As toxicity has not been completely revealed until now. Transcriptome analysis represents a powerful tool for revealing the mechanisms conferring phenotype formation and is widely employed in crop breeding. Consequently, this review focuses on the recent advances in transcriptome analysis within the realm of low As breeding in rice. It particularly highlights the applications of transcriptome analysis in identifying genes responsive to As toxicity, revealing gene interaction regulatory modules and analyzing secondary metabolite biosynthesis pathways. Furthermore, the molecular mechanisms underlying rice As tolerance are updated, and the recent outcomes in low As breeding are summarized. Finally, the challenges associated with applying transcriptome analysis to low-As breeding are deliberated upon, and future research directions are envisioned, with the aim of providing references to expedite high-yield and low-arsenic breeding in rice.

Exploring the benefits of AMF colonization for improving wheat growth, physiology and metabolism, and antimicrobial activity under biotic stress from aphid infection

BACKGROUND

This study examines the effectiveness of arbuscular mycorrhizal fungi (AMF, Rhizophagus irregularis) as a bioprotection strategy to improve wheat's physiological and biochemical responses. This study utilized soil inoculation with AMF and plant-controlled infestation with aphids, conducted over four weeks with three replicates per treatment.

RESULTS

Although aphid infestation reduced root colonization by 26.8% and hyphal length by 30.7%, with no effect on arbuscular numbers (p < 0.05), AMF treatment improved growth, physiology, and metabolism of AMF-treated plants, especially under aphid infestation. AMF-treated plants showed a 51% increase in fresh weight and a 38% improvement in photosynthetic rates under infestation, indicating enhanced photosynthetic efficiency compared to controls. At the metabolism level, AMF application, particularly in infested plants, increased the levels of several amino acids, such as asparagine and glutamine, which increased by 23% and 20%, respectively. AMF treatment significantly boosted nitrogen metabolism enzymes, with activity increasing up to 4.8-fold in infested plants and arginase activity rising by 49% in infested and 290% in non-infested conditions. This metabolic shift elevated antioxidant levels, increasing flavonoids by 40% and polyphenols by 95% under aphid infestation. Additionally, antimicrobial efficacy improved, with AMF-treated plant extracts showing 30-67% larger inhibition zones against pathogens like Staphylococcus epidermidis and Salmonella typhimurium than untreated plants (p < 0.05).

CONCLUSIONS

This research examined the potential of AMF as a sustainable pest management tool, specifically focusing on its ability to enhance crop health and boost defenses against biotic stress. The study further highlights how AMF treatment improves antimicrobial efficacy, which can be integrated into farming practices to maintain plant growth while offering distinct advantages over conventional pest management strategies.

Removal of Antimony(V) from aqueous solutions by electrodeionization

This study investigates the removal efficiency of the toxic element antimony (Sb(V)) using a combined system incorporating ion exchange resins and ion exchange membranes to form an Electrodeionization (EDI) cell. The impact of various operational parameters, including applied potential, flow rate, Na₂SO₄ concentration in the electrode compartment, and the presence of interfering ions, on Sb(V) removal was systematically examined. Results indicate that increasing the applied potential significantly enhances Sb(V) removal, achieving a maximum removal rate of 99% at 40 V and 50 V, with the residual Sb(V) concentrations reducing to 60 μg/L and 9 μg/L, respectively. Variation in flow rate from 1 L/h to 3 L/h showed that removal efficiency peaks at 99% for flow rates of 2 L/h and above. Adjusting the Na₂SO₄ concentration from 0.005 M to 0.05 M in the electrode compartment also improves removal efficiency, maintaining a rate of 99%. Furthermore, the presence of low concentrations of Cl⁻, SO₄2⁻, NO₃⁻, and PO₄³⁻ ions resulted in achieving a 99% removal efficiency of Sb(V). These findings demonstrate the system's robustness and potential for effective Sb(V) removal from aqueous solutions under varying operational conditions.

Proteomic Analysis Reveals Differentially Expressed Proteins in Cordyceps militaris Cultured with Different Media

Cordyceps militaris is rich in high quality protein, which is an excellent protein supplement. In this study, proteins were extracted from C. militaris cultured with tussah pupa and C. militaris cultured with wheat and analyzed by liquid chromatography coupled with mass spectrometer. Results showed that a total of 83 differentially expressed proteins (DEPs) were identified. KEGG analysis showed that the number of DEPs involved in amino sugar and nucleotide sugar metabolism and metabolic pathways was the largest. The expression levels of chitinase, tubulin alpha chain and heat shock 70 kDa protein were upregulated in C. militaris cultured with tussah pupa, and these key DEPs were mainly related to immune modulation and disease resistance. The results revealed the nutritional and functional differences in the fruiting bodies of C. militaris cultured with tussah pupa and wheat, respectively. The findings provide a theoretical basis for further studies on the biological function of proteins in C. militaris.

Influence of rhizospheric symbiotic microorganisms on the behavioural effects of antimony in soil-plant system: Insights from a proteomic perspective

Antimony (Sb) pollution in soil-rice systems can affect human health by enriching of food chains. Currently, the mechanism of the negative role underlying microorganisms in plant responses to Sb stress remains clear. The results of this study showed that the presence of arbuscular mycorrhizal (AM) fungi, a common symbiotic microorganism in rhizosphere soil, significantly enhanced Sb uptake by upland rice and inhibited its growth. Furthermore, we explained the reasons for the adverse effects of AM fungi mediation on upland rice growth under Sb stress from a molecular perspective. The results also showed that AM fungi affect the biological processes of the response of upland rice to oxidative stress and the functions of its antioxidant active molecules throughout the vegetative growth phase of upland rice, and that the phenylpropanoid biosynthesis pathway is significantly downregulated. At the same time, phenylalanine/tyrosine ammonia-lyase (PTAL) in the pathway was significantly expressed in the middle and late stages of vegetative growth of upland rice. Therefore, PTAL can act as a potential reference protein to investigate the response of upland rice to Sb stress mediated by AM fungi. These findings enrich our understanding of the impact of Sb pollution on soil-plant systems in real soil environments.

Migration, transformation of arsenic, and pollution controlling strategies in paddy soil-rice system: A comprehensive review

Arsenic pollution in paddy fields has become a public concern by seriously threatening rice growth, food security and human health. In this review, we delve into the biogeochemical behaviors of arsenic in paddy soil-rice system, systemically revealing the complexity of its migration and transformation processes, including the release of arsenic from soil to porewater, uptake and translocation of arsenic by rice plants, as well as transformation of arsenic species mediated by microorganism. Especially, microbial processes like reduction, oxidation and methylation of arsenic, and the coupling of arsenic with carbon, iron, sulfur, nitrogen cycling through microbes and related mechanisms were highlighted. Environmental factors like pH, redox potential, organic matter, minerals, nutrient elements, microorganisms and periphyton significantly influence these processes through different pathways, which are discussed in this review. Furthermore, the current progress in remediation strategies, including agricultural interventions, passivation, phytoremediation and microbial remediation is explored, and their potential and limitations are analyzed to address the gaps. This review offers comprehensive perspectives on the complicated behaviors of arsenic and influence factors in paddy soil-rice system, and provides a scientific basis for developing effective arsenic pollution control strategies.

Isolation and Identification of Highly Sb-Resistant Rhodotorula glutinis Strain J5 and its Mechanism of Resistance to Sb(III)

Sb-resistant strains can detoxify antimony through metabolic mechanisms such as oxidation and affect the migration, transformation, and ultimate fate of antimony in the environment. In this study, a strain of Sb-resistant fungi, Rhodotorula glutinis sp. Strain J5, was isolated from Xikuangshan mine and its growth characteristics, gene expression differences, and functional annotation under Sb(III) stress were further investigated to reveal the mechanism of resistance to Sb(III). We identified strain J5 as belonging to the Rhodotorula glutinis species optimally growing at pH 5.0 and at 28 °C of temperature. According to gene annotation and differential expression, the resistance mechanism of Strain J5 includes: reducing the endocytosis of antimony by aquaporin AQP8 and transmembrane transporter pst, enhancing the efflux of Sb(III) by the gene expression of acr2, acr3 and ABC, improving the oxidation of Sb(III) by iron-sulfur protein and Superoxide dismutase (SOD), glutathione (GSH) and cysteine (Cys) chelation, methylation of methyltransferase and N-methyltransferase, accelerating cell damage repair and EPS synthesis and other biochemical reaction mechanisms. FT-IR analysis shows that the -OH, -COOH, -NH, -PO, C-O, and other active groups of Strain J5 can be complexed with Sb(III), resulting in chemical adsorption. Strain J5 displays significant resistance to Sb(III) with the MIC of 1300 mg/L, playing a crucial role in the global biochemical transformation of antimony and its potential application in soil microbial remediation.

Managing antimony pollution: Insights into Soil-Plant system dynamics and remediation Strategies

Researchers are increasingly concerned about antimony (Sb) in ecosystems and the environment. Sb primarily enters the environment through anthropogenic (urbanization, industries, coal mining, cars, and biosolid wastes) and geological (natural and chemical weathering of parent material, leaching, and wet deposition) processes. Sb is a hazardous metal that can potentially harm human health. However, no comprehensive information is available on its sources, how it behaves in soil, and its bioaccumulation. Thus, this study reviews more than 160 peer-reviewed studies examining Sb's origins, geochemical distribution and speciation in soil, biogeochemical mechanisms regulating Sb mobilization, bioavailability, and plant phytotoxicity. In addition, Sb exposure effects plant physio-morphological and biochemical attributes were investigated. The toxicity of Sb has a pronounced impact on various aspects of plant life, including a reduction in seed germination and impeding plant growth and development, resulting from restricted essential nutrient uptake, oxidative damages, disruption of photosynthetic system, and amino acid and protein synthesis. Various widely employed methods for Sb remediation, such as organic manure and compost, coal fly ash, biochar, phytoremediation, microbial-based bioremediation, micronutrients, clay minerals, and nanoremediation, are reviewed with a critical assessment of their effectiveness, cost-efficiency, and suitability for use in agricultural soils. This review shows how plants deal with Sb stress, providing insights into lowering Sb levels in the environment and lessening risks to ecosystems and human health along the food chain. Examining different methods like bioaccumulation, bio-sorption, electrostatic attraction, and complexation actively works to reduce toxicity in contaminated agricultural soil caused by Sb. In the end, the exploration of recent advancements in genetics and molecular biology techniques are highlighted, which offers valuable insights into combating Sb toxicity. In conclusion, the findings of this comprehensive review should help develop innovative and useful strategies for minimizing Sb absorption and contamination and thus successfully managing Sb-polluted soil and plants to reduce environmental and public health risks.

Microbial mediated remediation of heavy metals toxicity: mechanisms and future prospects

Heavy metal pollution has become a serious concern across the globe due to their persistent nature, higher toxicity, and recalcitrance. These toxic metals threaten the stability of the environment and the health of all living beings. Heavy metals also enter the human food chain by eating contaminated foods and cause toxic effects on human health. Thus, remediation of HMs polluted soils is mandatory and it needs to be addressed at higher priority. The use of microbes is considered as a promising approach to combat the adverse impacts of HMs. Microbes aided in the restoration of deteriorated environments to their natural condition, with long-term environmental effects. Microbial remediation prevents the leaching and mobilization of HMs and they also make the extraction of HMs simple. Therefore, in this context recent technological advancement allowed to use of bioremediation as an imperative approach to remediate polluted soils. Microbes use different mechanisms including bio-sorption, bioaccumulation, bioleaching, bio-transformation, bio-volatilization and bio-mineralization to mitigate toxic the effects of HMs. Thus, keeping in the view toxic HMs here in this review explores the role of bacteria, fungi and algae in bioremediation of polluted soils. This review also discusses the various approaches that can be used to improve the efficiency of microbes to remediate HMs polluted soils. It also highlights different research gaps that must be solved in future study programs to improve bioremediation efficency.

Enhancing plant resilience: arbuscular mycorrhizal fungi's role in alleviating drought stress in vegetation concrete

Introduction

Drought stress usually inhibits plant growth, which may increase the difficulty of greening slopes.

Methods

In this study, we systematically investigated the effects of arbuscular mycorrhizal (AM) fungi on the growth and drought tolerance of two plant species, Festuca elata and Cassia glauca, in a vegetation concrete environment by exogenously inoculating AM fungi and setting three drought levels: well water, moderate drought and severe drought. The results showed that plant growth was significantly inhibited under drought stress; however, AM fungi inoculation significantly promoted plant height, root length, and above- and belowground biomass in these two plant species.

Results

Compared with, those in the CK treatment, the greatest increases in the net photosynthesis rate, stomatal conductance and transpiration rate in the AM treatment group were 36.72%, 210.08%, and 66.41%, respectively. Moreover, inoculation with AM fungi increased plant superoxide dismutase and catalase activities by 4.70-150.73% and 9.10-95.70%, respectively, and reduced leaf malondialdehyde content by 2.79-55.01%, which alleviated the damage caused by oxidative stress. These effects alleviated the damage caused by oxidative stress and increased the content of soluble sugars and soluble proteins in plant leaves by 1.52-65.44% and 4.67-97.54%, respectively, which further increased the drought adaptability of plants. However, inoculation with AM fungi had different effects on different plants.

Conclusion

In summary, this study demonstrated that the inoculation of AM fungi in vegetation concrete environments can significantly increase plant growth and drought tolerance. The plants that formed a symbiotic structure with AM fungi had a larger root uptake area, greater water uptake capacity, and greater photosynthesis and gas exchange efficiency. In addition, AM fungi inoculation further increased the drought adaptability of the plants by increasing their antioxidant enzyme activity and regulating their metabolite content. These findings are highly important for promoting plant growth and increasing drought tolerance under drought conditions, especially for potential practical applications in areas such as slope protection, and provide useful references for future ecological engineering and sustainable development.

Improving plant adaptation to soil antimony contamination: the synergistic contribution of arbuscular mycorrhizal fungus and olive mill waste

BACKGROUND

This study aimed to investigate the alterations in biochemical and physiological responses of oat plants exposed to antimony (Sb) contamination in soil. Specifically, we evaluated the effectiveness of an arbuscular mycorrhizal fungus (AMF) and olive mill waste (OMW) in mitigating the effects of Sb contamination. The soil was treated with a commercial strain of AMF (Rhizophagus irregularis) and OMW (4% w/w) under two different levels of Sb (0 and 1500 mg kg-1 soil).

RESULTS

The combined treatment (OMW + AMF) enhanced the photosynthetic rate (+ 40%) and chlorophyll a (+ 91%) and chlorophyll b (+ 50%) content under Sb condition, which in turn induced more biomass production (+ 67-78%) compared to the contaminated control plants. More photosynthesis in OMW + AMF-treated plants gives a route for phenylalanine amino acid synthesis (+ 69%), which is used as a precursor for the biosynthesis of secondary metabolites, including flavonoids (+ 110%), polyphenols (+ 26%), and anthocyanins (+ 63%) compared to control plants. More activation of phenylalanine ammonia-lyase (+ 38%) and chalcone synthase (+ 26%) enzymes in OMW + AMF-treated plants under Sb stress indicated the activation of phenylpropanoid pathways in antioxidant metabolites biosynthesis. There was also improved shifting of antioxidant enzyme activities in the ASC/GSH and catalytic pathways in plants in response to OMW + AMF and Sb contamination, remarkably reducing oxidative damage markers.

CONCLUSIONS

While individual applications of OMW and AMF also demonstrated some degree of plant tolerance induction, the combined presence of AMF with OMW supplementation significantly enhanced plant biomass production and adaptability to oxidative stress induced by soil Sb contamination.

How plants respond to heavy metal contamination: a narrative review of proteomic studies and phytoremediation applications

MAIN CONCLUSION

Heavy metal pollution caused by human activities is a serious threat to the environment and human health. Plants have evolved sophisticated defence systems to deal with heavy metal stress, with proteins and enzymes serving as critical intercepting agents for heavy metal toxicity reduction. Proteomics continues to be effective in identifying markers associated with stress response and metabolic processes. This review explores the complex interactions between heavy metal pollution and plant physiology, with an emphasis on proteomic and biotechnological perspectives. Over the last century, accelerated industrialization, agriculture activities, energy production, and urbanization have established a constant need for natural resources, resulting in environmental degradation. The widespread buildup of heavy metals in ecosystems as a result of human activity is especially concerning. Although some heavy metals are required by organisms in trace amounts, high concentrations pose serious risks to the ecosystem and human health. As immobile organisms, plants are directly exposed to heavy metal contamination, prompting the development of robust defence mechanisms. Proteomics has been used to understand how plants react to heavy metal stress. The development of proteomic techniques offers promising opportunities to improve plant tolerance to toxicity from heavy metals. Additionally, there is substantial scope for phytoremediation, a sustainable method that uses plants to extract, sequester, or eliminate contaminants in the context of changes in protein expression and total protein behaviour. Changes in proteins and enzymatic activities have been highlighted to illuminate the complex effects of heavy metal pollution on plant metabolism, and how proteomic research has revealed the plant's ability to mitigate heavy metal toxicity by intercepting vital nutrients, organic substances, and/or microorganisms.

Characterization of an antimony-resistant fungus Sarocladium kiliense ZJ-1 and its potential as an antimony bio-remediator

Antimony (Sb) is a toxic metalloid widely distributed in the natural environments. Microorganisms, especially fungi, could serve as ideal biomaterials for bioremediation of Sb-polluted soils and waters. In this study, we isolated an antimony-resistant fungus, Sarocladium kiliense ZJ-1, from a slag sample collected in Xikuangshan Sb mine in P. R. China. ZJ-1 showed an extremely high resistance to Sb, with a MIC level of > 175 mM for arsenite [Sb(Ⅲ)] and 40 mM for arsenate [Sb(V)]. Whole genomic analysis identified multiple Sb (Ⅲ)- and/or As(Ⅲ)-resistant genes on ZJ-1's genome, which may partially explain its hyper-resistance to Sb. The potential of ZJ-1 in removing Sb from Sb(Ⅲ) or Sb(V) solutions was also quantified. The average biosorption capacity of ZJ-1 for Sb(Ⅲ) and Sb(V) is 635.14 mg/g and 149.65 mg/g, respectively, in Sb aqueous solutions with an initial concentration of 2000 mg/L (16.43 mM). Besides, almost 99% of Sb(Ⅲ) in the growing system was removed with an initial concentration of 500 mg/L (4.11 mM). Furthermore, Fourier transformation infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) were used to probe the Sb adsorption mechanism on ZJ-1, and -OH, -NH2, -COOH, C-O and C-O-C were found to be the main surface functional groups of ZJ-1 cells to adsorb Sb.

Proteomics-based analysis on the stress response mechanism of Bidens pilosa L. under cadmium exposure

Bidens pilosa L. (B. pilosa) has great potential for the phytoremediation of cadmium (Cd)-contaminated soils. However, the molecular mechanism underlying Cd tolerance and detoxification in B. pilosa is still unclear. In the present study, a 4D label-free quantification technique combined with liquid chromatography-parallel reaction monitoring mass spectrometry was used to explore the stress response mechanism of B. pilosa. Proteomic analysis revealed 213 and 319 differentially expressed proteins (DEPs) in the roots and leaves of B. pilosa, respectively, and 12 target proteins were selected for further analysis. SWISS-MODEL was used to predict the 3D structures of the target proteins. The cation-ATPase-N structural domain and an ATPase-E1-E2 motif, which help to regulate ATPase function, were detected in the TR10519_c0_g1_ORF protein. In addition, the TR6620_c0_g1_ORF_1 and TR611_c1_g1_ORF proteins contained peroxidase-1 and peroxidase-2 motifs. The TR11239_c0_g1_ORF protein was found to belong to the Fe-SOD family, to have a dimeric structure and to contain a relatively high proportion of α-helices but few β-sheets, which play important roles in reactive oxygen intermediate scavenging. Thus, the current study provides an overview of the proteomic response of B. pilosa in scavenging of Cd-induced reactive oxygen intermediates and reveals key proteins involved in the stress response of B. pilosa under Cd exposure.

A review on sources of soil antimony pollution and recent progress on remediation of antimony polluted soils

Antimony (Sb) is a serious toxic and non-essential metalloid for animals, humans, and plants. The rapid increase in anthropogenic inputs from mining and industrial activities, vehicle emissions, and shoot activity increased the Sb concentration in the environment, which has become a serious concern across the globe. Hence, remediation of Sb-contaminated soils needs serious attention to provide safe and healthy foods to humans. Different techniques, including biochar (BC), compost, manures, plant additives, phyto-hormones, nano-particles (NPs), organic acids (OA), silicon (Si), microbial remediation techniques, and phytoremediation are being used globally to remediate the Sb polluted soils. In the present review, we described sources of soil Sb pollution, the environmental impact of antimony pollution, the multi-faceted nature of antimony pollution, recent progress in remediation techniques, and recommendations for the remediation of soil Sb-pollution. We also discussed the success stories and potential of different practices to remediate Sb-polluted soils. In particular, we discussed the various mechanisms, including bio-sorption, bio-accumulation, complexation, and electrostatic attraction, that can reduce the toxicity of Sb by converting Sb-V into Sb-III. Additionally, we also identified the research gaps that need to be filled in future studies. Therefore, the current review will help to develop appropriate and innovative strategies to limit Sb bioavailability and toxicity and sustainably manage Sb polluted soils hence reducing the toxic effects of Sb on the environment and human health.

Effects of Arbuscular Mycorrhizal Fungi on Robinia pseudoacacia L. Growing on Soils Contaminated with Heavy Metals

Arbuscular mycorrhizal fungi (AMF) have been shown to assist plants in increasing metal tolerance and accumulation in heavy metal (HM)-contaminated soils. Herein, a greenhouse pot experiment was conducted to assess the interactions of growth substrates (S1, S2, and S3, respectively) with various HM contamination and nutrient status sampling from a typical contaminated soil and tailings in Shuikoushan lead/zinc mining in Hunan province, China, and AMF inoculation obtained from plants in uncontaminated areas (Glomus mosseae, Glomus intraradices, and uninoculated, respectively) on the biomass and uptake of HMs and phosphorus (P) by the black locust plant (Robinia pseudoacacia L.). The results indicated that the inoculation with AMF significantly enhanced the mycorrhizal colonization of plant roots compared with the uninoculated treatments, and the colonization rates were found to be higher in S1 and S2 compared with S3, which were characterized with a higher nutrient availability and lead concentration. The biomass and heights of R. pseudoacacia were significantly increased by AMF inoculation in S1 and S2. Furthermore, AMF significantly increased the HM concentrations of the roots in S1 and S2 but decreased the HM concentrations in S3. Shoot HM concentrations varied in response to different AMF species and substrate types. Mycorrhizal colonization was found to be highly correlated with plant P concentrations and biomass in S1 and S2, but not in S3. Moreover, plant biomass was also significantly correlated with plant P concentrations in S1 and S2. Overall, these findings demonstrate the interactions of AMF inoculation and growth substrates on the phytoremediation potential of R. pseudoacacia and highlights the need to select optimal AMF isolates for their use in specific substrates for the remediation of HM-contaminated soil.

Arbuscular mycorrhizal fungi community analysis revealed the significant impact of arsenic in antimony- and arsenic-contaminated soil in three Guizhou regions

Introduction

The lack of systematic investigations of arbuscular mycorrhizal fungi (AMF) community composition is an obstacle to AMF biotechnological applications in antimony (Sb)- and arsenic (As)-polluted soil.

Methods

Morphological and molecular identification were applied to study the AMF community composition in Sb- and As-contaminated areas, and the main influencing factors of AMF community composition in Sb- and As-contaminated areas were explored.

Results

(1) A total of 513,546 sequences were obtained, and the majority belonged to Glomeraceae [88.27%, 193 operational taxonomic units (OTUs)], followed by Diversisporaceae, Paraglomeraceae, Acaulosporaceae, Gigasporaceae, and Archaeosporaceae; (2) the affinity between AMF and plants was mainly related to plant species (F = 3.488, p = 0.022 < 0.050), which was not significantly correlated with the total Sb (TSb) and total As (TAs) in soil; (3) the AMF spore density was mainly related to the available nitrogen, available potassium, and total organic carbon; (4) The effect of soil nutrients on AMF community composition (total explanation: 15.36%) was greater than that of soil Sb and As content (total explanation: 5.80%); (5) the effect of TAs on AMF community composition (λ = -0.96) was more drastic than that of TSb (λ = -0.21), and the effect of As on AMF community composition was exacerbated by the interaction between As and phosphorus in the soil; and (6) Diversisporaceae was positively correlated with the TSb and TAs.

Discussion

The potential impact of As on the effective application of mycorrhizal technology should be further considered when applied to the ecological restoration of Sb- and As-contaminated areas.

Uptake, tolerance, and detoxification mechanisms of antimonite and antimonate in Boehmeria nivea L

Boehmeria nivea L. (ramie) is a promising phytoremediation plant for antimony (Sb)-contaminated soils. However, the uptake, tolerance, and detoxification mechanisms of ramie to Sb, which are the basis for finding efficient phytoremediation strategies, remain unclear. In the present study, ramie was exposed to 0, 1, 10, 50, 100, and 200 mg/L of antimonite (Sb(III)) or antimonate (Sb(V)) for 14 days in hydroponic culture. The Sb concentration, speciation, subcellular distribution, and antioxidant and ionomic responses in ramie were investigated. The results illustrated that ramie was more effective in the uptake of Sb(III) than Sb(V). Most of the Sb accumulated in ramie roots, with the highest level reaching 7883.58 mg/kg. Sb(V) was the predominant species in leaves, with 80.77-96.38% and 100% in the Sb(III) and Sb(V) treatments, respectively. Immobilization of Sb on the cell wall and leaf cytosol was the primary mechanism of accumulation. Superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) contributed significantly to root defense against Sb(III), while CAT and glutathione peroxidase (GPX) were the major antioxidants in leaves. CAT and POD played crucial roles in the defense against Sb(V). B, Ca, K, Mg, and Mn in Sb(V)-treated leaves and K and Cu in Sb(III)-treated leaves may be related to the biological processes of Sb toxicity mitigation. This study is the first to investigate the ionomic responses of plants toward Sb and could provide valuable information for the phytoremediation of Sb-polluted soils.

Alleviation of metal stress in rape seedlings (Brassica napus L.) using the antimony-resistant plant growth-promoting rhizobacteria Cupriavidus sp. S-8-2

This study investigated an effective strategy for remediating antimony (Sb)-contaminated soil using the bacterial strain screened from Sb-contaminated fern rhizospheres due to its superior growth-promoting, heavy-metal(loid) resistant, and antibiotic-tolerant characteristics. The strain that belongs to Cupriavidus sp. was determined by 16S rRNA sequencing and showed no morphological changes when grown with high concentrations of Sb (608.8 mg/L). The strain showed prominent indole acetic acid (IAA), phosphate-solubilizing abilities, and ACC deaminase activity under Sb stress. Moreover, IAA and soluble phosphate levels increased in the presence of 608.8 mg/L Sb. Inoculation of rape seedlings with Cupriavidus sp. S-8-2 enhanced several morphological and biochemical growth features compared to untreated seedlings grown under Sb stress. Inoculation of Cupriavidus sp. S-8-2 increased root weight by more than four-fold for fresh weight and over two-fold for dry weight, despite high environmental Sb. The strain also reduced Sb-mediated oxidative stress and malondialdehyde contents by reducing Sb absorption, thus alleviating Sb-induced toxicity. Environmental Scanning Electron Microscope (ESEM) imaging and dilution plating technique revealed Cupriavidus sp. S-8-2 is localized on the surface of roots. Identifying the Sb-resistant plant growth-promoting bacterium suggested its usefulness in the remediation of contaminated agricultural soil and for the promotion of crop growth. We highly recommend the strain for further implementation in field experiments.

Capacity of Nerium oleander to Phytoremediate Sb-Contaminated Soils Assisted by Organic Acids and Oxygen Nanobubbles

Antimony (Sb) is considered to be a toxic metalloid of increasing prevalence in the environment. Although several phytoremediation studies have been conducted, research regarding the mechanisms of Sb accumulation and translocation within plants remains limited. In this study, soil from a shooting range was collected and spiked with an initial Sb(III) concentration of 50 mg/kg. A pot experiment was conducted to investigate whether Nerium oleander could accumulate Sb in the root and further translocate it to the aboveground tissue. Biostimulation of the soil was performed by the addition of organic acids (OAs), consisting of citric, ascorbic, and oxalic acid at low (7 mmol/kg) or high (70 mmol/kg) concentrations. The impact of irrigation with water supplemented with oxygen nanobubbles (O2NBs) was also investigated. The results demonstrate that there was a loss in plant growth in all treatments and the presence of OAs and O2NBs assisted the plant to maintain the water content at the level close to the control. The plant was not affected with regards to chlorophyll content in all treatments, while the antioxidant enzyme activity of guaiacol peroxidase (GPOD) in the roots was found to be significantly higher in the presence of Sb. Results revealed that Sb accumulation was greater in the treatment with the highest OAs concentration, with a bioconcentration factor greater than 1.0. The translocation of Sb for every treatment was very low, confirming that N. oleander plant cannot transfer Sb from the root to the shoots. A higher amount of Sb was accumulated in the plants that were irrigated with the O2NBs, although the translocation of Sb was not increased. The present study provides evidence for the phytoremediation capacity of N. oleander to bioaccumulate Sb when assisted by biostimulation with OAs.

Toxic effects of antimony in plants: Reasons and remediation possibilities-A review and future prospects

Antimony (Sb) is a dangerous heavy metal (HM) that poses a serious threat to the health of plants, animals, and humans. Leaching from mining wastes and weathering of sulfide ores are the major ways of introducing Sb into our soils and aquatic environments. Crops grown on Sb-contaminated soils are a major reason of Sb entry into humans by eating Sb-contaminated foods. Sb toxicity in plants reduces seed germination and root and shoot growth, and causes substantial reduction in plant growth and final productions. Moreover, Sb also induces chlorosis, causes damage to the photosynthetic apparatus, reduces membrane stability and nutrient uptake, and increases oxidative stress by increasing reactive oxygen species, thereby reducing plant growth and development. The threats induced by Sb toxicity and Sb concentration in soils are increasing day by day, which would be a major risk to crop production and human health. Additionally, the lack of appropriate measures regarding the remediation of Sb-contaminated soils will further intensify the current situation. Therefore, future research must be aimed at devising appropriate measures to mitigate the hazardous impacts of Sb toxicity on plants, humans, and the environment and to prevent the entry of Sb into our ecosystem. We have also described the various strategies to remediate Sb-contaminated soils to prevent its entry into the human food chain. Additionally, we also identified the various research gaps that must be addressed in future research programs. We believe that this review will help readers to develop the appropriate measures to minimize the toxic effects of Sb and its entry into our ecosystem. This will ensure the proper food production on Sb-contaminated soils.

Effects of Antimony on Rice Growth and Its Existing Forms in Rice Under Arbuscular Mycorrhizal Fungi Environment

Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with most terrestrial plants and regulate the uptake and distribution of antimony (Sb) in rice. The effect of AMF on the uptake and transport of Sb in rice was observed using pot experiments in the greenhouse. The results showed that AMF inoculation increased the contact area between roots and metals by forming mycelium, and changed the pH and Eh of the root soil, leading to more Sb entering various parts of the rice, especially at an Sb concentration of 1,200 mg/kg. The increase in metal toxicity further led to a decrease in the rice chlorophyll content, which directly resulted in a 22.7% decrease in aboveground biomass, 21.7% in underground biomass, and 11.3% in grain biomass. In addition, the antioxidant enzyme results showed that inoculation of AMF decreased 22.3% in superoxide dismutase, 9.9% in catalase, and 20.7% in peroxidase compared to the non-inoculation groups, further verifying the negative synergistic effect of AMF inoculation on the uptake of Sb in rice. The present study demonstrated the effect of AMF on the uptake and transport of Sb in the soil–rice system, facilitating future research on the related mechanism in the soil–rice system under Sb stress.