Combined Bioremediation of Bensulfuron-Methyl Contaminated Soils With Arbuscular Mycorrhizal Fungus and Hansschlegelia zhihuaiae S113

Advancing crop resilience through nucleic acid innovations: rhizosphere engineering for food security and climate adaptation

Rhizosphere engineering has emerged as a transformative strategy to address the pressing challenges of climate change, food security, and environmental sustainability. By harnessing the dynamic interactions between plants and microbes, and environmental processes, this approach offers innovative solutions for enhancing crop production, protecting against pests and diseases, and remediating contaminated environments. This review explores how rhizosphere engineering, both plant-based and microbe-based, can be leveraged to enhance crop productivity, manage pests and diseases, and remediate contaminated environments under shifting climate conditions. We examine the effects of climate change drivers such as elevated CO2, increased N deposition, rising temperatures, and altered precipitation patterns, on plant-microbe interactions and rhizosphere processes. We show that climate change impacts key functions, including respiration, decomposition and stabilization of soil organic matter, nutrient cycling, greenhouse gas emissions, and microbial community dynamics. Despite these challenges, engineered rhizospheres can mitigate adverse effects of climate change by improving rhizodeposition, nitrogen fixation, root architecture modification, selective microbe recruitment, and pathogen control, while enhancing carbon allocation and stabilization in soil. However, the deployment of these technologies is not without challenges. Ecological risks, such as unintended gene transfer and disruption of native microbial communities, as well as socioeconomic barriers, must be carefully addressed to ensure safe and scalable implementation. We identify critical research gaps such as the limited understanding of multi-taxon cooperation and scalability in engineered rhizosphere systems, and how mechanistic understanding of designer plants and microbes can advance crop production, protection, and environmental remediation in agriculture and agroforestry under global changes.

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) derived from cobalt/iron solid complex as peroxymonosulfate (PMS) activator for efficient bensulfuron-methyl degradation

Cobalt/iron bimetallic oxide coated with graphitized nitrogen-doped carbon (Fe2O3-CoO@NC) was synthesized by convenient solid phase coordination combined with calcination method to activate PMS for the degradation of BSM. A series of Co/Fe bimetallic oxides with different metal ratios were designed and prepared to select the most efficient catalyst and Fe2O3-CoO@NC(Co:Fe = 1:1) demonstrated the highest catalytic activity and the lowest ions leaching. The reasons for high catalytic activity of Fe2O3-CoO@NC(Co:Fe = 1:1) were evaluated by a range of characterization techniques and the results showed it stemmed from higher mental content and larger current density. Complete (100%) degradation of 10 g L-1 BSM was achieved within 10 min under the conditions of 0.05 g L-1 catalyst and 0.3 mmol/L PMS dosage at 25 °C. Moreover, Fe2O3-CoO@NC(Co:Fe = 1:1) showed more excellent catalytic activity and lower ions leaching than Fe2O3, CoO and Fe2O3-CoO, indicating superior bimetallic synergy and carbon encapsulation effect. Furtherly, radical experiments and XPS analysis revealed the main active species and catalytic mechanism of the Fe2O3-CoO@NC/PMS system, respectively. Finally, the degradation pathway of BSM by Fe2O3-CoO@NC/PMS system was deduced by LC-TOF-MS. This paper is aimed to provide a new insight into the convenient preparation method for the construction of catalysts which could reach efficient removal of complex organic pollutants.

MgO anchored N-doping biochar enhances the bensulfuron-methyl biodegradation by Acinetobacter YH0317: Higher reactive oxygen species level and bacterial viability

Bensulfuron-methyl (BSM) is a typical broad-spectrum sulfonylurea herbicide and the runoff of BSM residues from agricultural regions poses a significant threat to the ecosystem. Here we develop a bacteria-material hybrid system constructed by Acinetobacter YH0317 and Mg(NO3)2 modified biochar (MBC) for efficiently degrading BSM under various conditions including pH and temperature. Results showed that BSM biodegradation efficiency by YH0317&MBC (96.7 %) was significantly higher than YH0317&BC (79.5 %) and YH0317 (43.9 %) at 15 °C after 7 d of incubation. The addition of MBC significantly increased the reactive oxygen species (ROS) level, which was significantly higher than group YH0317. Moreover, the bacterial viability, extracellular polymeric substances (EPS) production, and membrane permeability of YH0317 were also enhanced with the addition of MBC. The electron paramagnetic resonance (EPR) and quenching experiments revealed that singlet oxygen (1O2) was the dominant active substance produced by MBC. The YH0317&MBC could effectively remove the BSM, and reduce the oxidative stress to soybean, which was beneficial to the growth of soybean through hydroponic experiment. This study establishes a microorganism-material system that efficiently removes BSM in aquatic environments and emphasizes the importance of ROS in pollution removal by the hybrid system.

Nitrogen and magnesium codoped biochar activates periodate to remediate bensulfuron methyl-contaminated water at low temperature: Performance, mechanisms, and phytotoxicity

Bensulfuron methyl (BSM), a typical sulfonylurea herbicide, has been widely used worldwide for weed suppression and crop protection. Nevertheless, the long-term and prolonged usage led to residues in environment, resulting in the reduction of crop yields and even threatening food security. In this study, the nitrogen/magnesium codoped biochar (NMg-BC) was prepared via two-step pyrolysis method to activate periodate (PI) for BSM degradation. The results demonstrated BSM degradation rate was 87.9 % within 10 min by NMg-BC/PI system at 15 ℃. The system exhibited the favorable tolerance to environmental changes (pH, temperature, anions, and humic acids), presenting high removal efficiency of BSM. Radicals (IO3•) and non-radicals (1O2 and electron transfer) pathways contributed to the degradation of BSM, while the latter performed a crucial role in BSM degradation. Theoretical calculations further confirmed doped of N and Mg changed the electron configuration and electrostatic potential (ESP) distribution of biochar, which was beneficial to provide more active sites for PI activation. Hydroponic experiments showed that NMg-BC/PI system could effectively degrade BSM, and its residue had no significant effect on the length and weight of soybean. The study provides a promising approach for the pollutant remediation in cold regions.

Simultaneous achievement of removing bensulfuron-methyl and reducing CO2 emission in paddy soil by Acinetobacter YH0317 immobilized boron-doping biochar

Herbicide residue and greenhouse gas (GHG) emission are two main problems in the paddy rice field, which have barely been considered simultaneously. Herein, a bensulfuron-methyl (BSM)-degrading bacterium named Acinetobacter YH0317 was successfully immobilized on two kinds of biochars and subsequently applied in the paddy soil. The BSM removal rate of Acinetobacter YH0317 immobilized boron-doping biochar (BBC) was 80.42% after 30 d, which was significantly higher than that of BBC (39.05%) and Acinetobacter YH0317 (49.10%) applied alone. BBC acting as an immobilized carrier could enable Acinetobacter YH0317 to work in harsh and complex environment and thus improve the BSM removal efficiency. The addition of Acinetobacter YH0317 immobilized BBC (TP5) significantly improved the soil physicochemical properties (pH, SOC, and NH4+-N) and increased the diversity of soil microbial community compared to control group (CG). Meanwhile, Acinetobacter YH0317 immobilized BBC reduced the CO2-equivalent emission by 41.0%. Metagenomic sequencing results revealed that the decreasing CO2 emission in TP5 was correlated with carbon fixation gene (fhs), indicating that fhs gene may play an important role in reducing CO2 emission. The work presents a practical and supportive technique for the simultaneous achievement on the soil purification and GHG emission reduction in paddy soil.

Trophic relationships between protists and bacteria and fungi drive the biogeography of rhizosphere soil microbial community and impact plant physiological and ecological functions

Rhizosphere microorganisms play a vital role in enhancing plant health, productivity, and the accumulation of secondary metabolites. Currently, there is a limited understanding of the ecological processes that control the assembly of community. To address the role of microbial interactions in assembly and for functioning of the rhizosphere soil microbiota, we collected rhizosphere soil samples from Anisodus tanguticus on the Tibetan Plateau spanning 1500 kilometers, and sequenced the bacteria, fungi, archaea, and protist communities. We observed a significant but weak distance-decay relationship in the microbial communities of rhizosphere soil. Our comprehensive analysis of spatial, abiotic, and biotic factors showed that trophic relationships between protists and bacteria and fungi predominantly influenced the alpha and beta diversity of bacterial, fungal, and protistan communities, while abiotic factors had a greater impact on archaeal communities, including soil pH, available phosphorus, total phosphorus and mean annual temperature. Importantly, microbial interactions had a more significant influence on Anisodus tanguticus physiological and ecological functions compared to individual microorganisms. Network analyses revealed that bacteria occupy a central position of the co-occurrence network and play a crucial role of connector within this community. The addition of protists increased the stability of bacterial, fungal, and archaeal networks. Overall, our findings indicate that trophic relationships play an important role in assembly and for functioning of the rhizosphere soil microbiota. Bacterial communities serve as a crucial link between different kingdoms of microorganisms in the rhizosphere community. These findings help us to fully harness the beneficial functions of rhizosphere microorganisms for plants and achieve sustainable use of biological resources.

Amide herbicides: Analysis of their environmental fate, combined plant-microorganism soil remediation scheme, and risk prevention and control strategies for sensitive populations

In this study, we predicted the environmental fate of amide herbicides (AHs) using the EQC (EQuilibrium Criterion) model. We found that the soil phase is the main reservoir of AHs in the environment. Second, a toxicokinetic prediction indicated that butachlor have a low human health risk, while the alachlor, acetochlor, metolachlor, napropamide, and propanil are all uncertain. To address the environmental and human-health-related threats posed by AHs, 27 new proteins/enzymes that easily absorb, degrade, and mineralize AHs were designed. Compared with the target protein/enzyme, the comprehensive evaluation value of the new proteins/enzymes increased significantly: the absorption protein increased by 20.29-113.49%; the degradation enzyme increased by 151.26-425.22%; and the mineralization enzyme increased by 23.70-52.16%. Further experiments revealed that the remediating effect of 13 new proteins/enzymes could be significantly enhanced to facilitate their applicability under real environmental conditions. The hydrophobic interactions, van der Waals forces, and polar solvation are the key factors influencing plant-microorganism remediation. Finally, the simulations revealed that appropriate consumption of kiwifruit or simultaneous consumption of ginseng, carrot, and spinach, and avoiding the simultaneous consumption of maize and carrot/spinach are the most effective means reduce the risk of exhibiting AH-linked toxicity.

Enhanced removal efficiency of bensulfuron-methyl by a novel boron doping biochar-based Acinetobacter YH0317 at a lower temperature

Biochar-based bacteria are regarded as an efficient strategy for remediating organic pollutants in aquatic environments. Herein, a strain named Acinetobacter YH0317 that could degrade bensulfuron-methyl (BSM) at a lower temperature (15 °C) was isolated from a paddy rice field with long-term BSM application. Then Acinetobacter YH0317 was loaded on unmodified biochar (BC) and boron doping biochar (BBC). Results showed that BBC-based YH0317 significantly enhanced the removal efficiency of BSM (71.8-99.1%) compared with BC-based YH0317 (41.9-44.0%) and YH0317 alone (18.1-20.7%) in 24 h. BBC promoted the growth of YH0317 and secretion of extracellular secretions by providing a carrier and shelter for YH0317. The electrochemical analysis suggested BBC improved the electron transfer rate, which ultimately facilitated the removal of BSM. Hydroponic experiments indicated that BBC-based YH0317 effectively improved the growth of soybean. This work reports a novel BBC-based Acinetobacter YH0317 that could effectively remediate BSM contamination in the water environment.

Current insights into the microbial degradation of nicosulfuron: Strains, metabolic pathways, and molecular mechanisms

Nicosulfuron is among the sulfonylurea herbicides that are widely used to control annual and perennial grass weeds in cornfields. However, nicosulfuron residues in the environment are likely to cause long-lasting harmful environmental and biological effects. Nicosulfuron degrades via photo-degradation, chemical hydrolysis, and microbial degradation. The latter is crucial for pesticide degradation and has become an essential strategy to remove nicosulfuron residues from the environment. Most previous studies have focused on the screening, degradation characteristics, and degradation pathways of biodegrader microorganisms. The isolated nicosulfuron-degrading strains include Bacillus, Pseudomonas, Klebsiella, Alcaligenes, Rhodopseudomonas, Ochrobactrum, Micrococcus, Serratia, Penicillium, Aspergillus, among others, all of which have good degradation efficiency. Two main intermediates, 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), are produced during microbial degradation and are derived from the C-N, C-S, and S-N bond breaks on the sulfonylurea bridge, covering almost every bacterial degradation pathway. In addition, enzymes related to the degradation of nicosulfuron have been identified successively, including the manganese ABC transporter (hydrolase), Flavin-containing monooxygenase (oxidase), and E3 (esterase). Further in-depth studies based on molecular biology and genetics are needed to elaborate on their role in the evolution of novel catabolic pathways and the microbial degradation of nicosulfuron. To date, few reviews have focused on the microbial degradation and degradation mechanisms of nicosulfuron. This review summarizes recent advances in nicosulfuron degradation and comprehensively discusses the potential of nicosulfuron-degrading microorganisms for bioremediating contaminated environments, providing a reference for further research development on nicosulfuron biodegradation in the future.

Enhanced adsorption performance of bensulfuron methyl with B doping biochar: Mechanism and density functional theory calculations

It is an urgent task to develop suitable adsorbents for the control of herbicide-bensulfuron methyl (BSM) in the paddy rice fields at cold regions. Herein, B doping biochar was synthesized via one-step method. Results showed that the adsorption capacity for BSM on 1.0BBC was significantly superior to BC at 15 °C. Besides, low temperature resistance, wide pH adaptability, stable adsorption performance and reusability test suggested that 1.0BBC have potential practical application. The mechanisms of BSM removal by 1.0BBC were mainly attributed to pore filling and π-π electron donor-acceptor (EDA) interaction. Theoretical calculations revealed that BCO₂ could enhance the adsorption capacity by π-π EDA between BSM and adsorbent. Meanwhile, hydroponic experiment demonstrated that the toxicity to soybean after adsorption of BSM by 1.0BBC was within the safe range. This study proves that 1.0BBC is an easy-to-prepare adsorbent with promising application in BSM removal in the rice paddy fields at lower temperature.

Immobilization of bacterial mixture of Klebsiella variicola FH-1 and Arthrobacter sp. NJ-1 enhances the bioremediation of atrazine-polluted soil environments

In this study, the effects of the immobilized bacterial mixture (IM-FN) of Arthrobacter sp. NJ-1 and Klebsiella variicola strain FH-1 using sodium alginate-CaCl2 on the degradation of atrazine were investigated. The results showed that the optimal ratio of three types of carrier materials (i.e., rice straw powder, rice husk, and wheat bran) was 1:1:1 with the highest adsorption capacity for atrazine (i.e., 3774.47 mg/kg) obtained at 30°C. On day 9, the degradation efficiency of atrazine (50 mg/L) reached 98.23% with cell concentration of 1.6 × 108  cfu/ml at pH 9 and 30°C. The Box-Behnken method was used to further optimize the culture conditions for the degradation of atrazine by the immobilized bacterial mixture. The IM-FN could be reused for 2-3 times with the degradation efficiency of atrazine maintained at 73.0% after being stored for 80 days at 25°C. The population dynamics of IM-FN was explored with the total soil DNA samples specifically analyzed by real-time PCR. In 7 days, the copy numbers of both PydC and estD genes in the IM-FN were significantly higher than those of bacterial suspensions in the soil. Compared with bacterial suspensions, the IM-FN significantly accelerated the degradation of atrazine (20 mg/kg) in soil with the half-life shortened from 19.80 to 7.96 days. The plant heights of two atrazine-sensitive crops (wheat and soybean) were increased by 14.99 and 64.74%, respectively, in the soil restored by immobilized bacterial mixture, indicating that the IM-FN significantly reduced the phytotoxicity of atrazine on the plants. Our study evidently demonstrated that the IM-FN could significantly increase the degradation of atrazine, providing a potentially effective bioremediation technique for the treatment of atrazine-polluted soil environment and providing experimental support for the wide application of immobilized microorganism technology in agriculture.

Development of solid agents of the diphenyl ether herbicide degrading bacterium Bacillus sp. Za based on a mixed organic fertilizer carrier

The long-term and widespread use of diphenyl ether herbicides has caused serious soil residue problems and threatens the agricultural ecological environment. The development of biodegrading agents using high-efficiency degrading strains as pesticide residue remediation materials has been widely recognized. In this study, the strain Bacillus sp. Za was used to prepare solid agents for the remediation of diphenyl ether herbicides-contaminated soil. The ratio of organic fertilizer was 1:3 (pig manure: cow dung), the inoculum amount of Za was 10%, the application amount of solid agents was 7%, and the application mode was mixed application, all of which were the most suitable conditions for solid agents. After the solid agents were stored for 120 days, the amount of Za remained above 10⁸ CFU/g. The degradation rates of the solid agents for lactofen, bifenox, fluoroglycofen, and fomesafen in soil reached 87.40, 82.40, 78.20, and 65.20%, respectively, on the 7th day. The application of solid agents alleviated the toxic effect of lactofen residues on maize seedlings. A confocal laser scanning microscope (CLSM) was used to observe the colonization of Za-gfp on the surface of maize roots treated in the solid agents, and Za-gfp mainly colonized the elongation zone and the mature area of maize root tips, and the colonization time exceeded 21 days. High-throughput sequencing analysis of soil community structural changes in CK, J (solid agents), Y (lactofen), and JY (solid agents + lactofen) groups showed that the addition of solid agents could restore the bacterial community structure in the rhizosphere soil of maize seedlings. The development of solid agents can facilitate the remediation of soil contaminated with diphenyl ether herbicide residues and improve the technical level of the microbial degradation of pesticide residues.