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Herbicide residuals have posed severe threat to food safety and public health; thus, the development of smart, portable, efficient, and accurate on‐site detection system is in urgent demand. Here, a multi‐emitting fluorescent system‐assisted lab‐in‐a‐syringe (LIS) device was developed for the on‐site and background‐free determination of 2,4‐dichlorophenoxyacetic acid (2,4‐D). 2,4‐D‐responsive cascade reactions were constructed: 2,4‐D could specifically suppress alkaline phosphatase (ALP) activity and restrain the generation of ascorbic acid (AA), MnO 2 nanosheets would oxidize AA into dehydroascorbic acid that subsequently reacts with o ‐phenylenediamine (OPD) to generate blue‐emission product ( λ em , 435 nm), whereas remained MnO 2 nanosheets and OPD further produced yellow‐emission product ( λ em , 570 nm). Red‐emission carbon dots (RCDs, λ em , 680 nm), synthesized via the solvothermal treatment of cilantro, were introduced to construct a multi‐emitting fluorescent system. Then, four paper pads, respectively, dropped with ALP, sodium l ‐ascorbyl‐2‐phosphate, MnO 2 nanosheets + RCDs, and OPD were held into reusable plastic filters and assembled paper‐based LIS device to trigger cascade reactions (total analysis time, 65 min) and eliminate background interference. As a result, with the support of color recognizer application in smartphone, fluorescent color on detection pads from blue–purple to red to yellow was achieved for the sensitive and visual detection of 2,4‐D with LOD of 5.0 μg L −1 , recoveries of 94.6%–106.8%, and relative standard deviations of 2.3%–6.8%. Obviously, this strategy provides a robust, visual, and background‐free platform for 2,4‐D detection, which expands application prospects in the field of herbicide analysis.

Synthetic chemical elicitors of plant defense have been touted as a powerful means for sustainable crop protection. Yet, they have never been successfully applied to control insect pests in the field. We developed a high-throughput chemical genetics screening system based on a herbivore-induced linalool synthase promoter fused to a β-glucuronidase (GUS) reporter construct to test synthetic compounds for their potential to induce rice defenses. We identified 2,4-dichlorophenoxyacetic acid (2,4-D), an auxin homolog and widely used herbicide in monocotyledonous crops, as a potent elicitor of rice defenses. Low doses of 2,4-D induced a strong defensive reaction upstream of the jasmonic acid and ethylene pathways, resulting in a marked increase in trypsin proteinase inhibitor activity and volatile production. Induced plants were more resistant to the striped stem borer Chilo suppressalis, but became highly attractive to the brown planthopper Nilaparvata lugens and its main egg parasitoid Anagrus nilaparvatae. In a field experiment, 2,4-D application turned rice plants into living traps for N. lugens by attracting parasitoids. Our findings demonstrate the potential of auxin homologs as defensive signals and show the potential of the herbicide to turn rice into a selective catch crop for an economically important pest.

* A new pulsed switching peroxi-coagulation (PSPC) system was developed. * The EC T for 2,4-D removal in the PSPC was lower than that in the EF. * The iron consumption for 2,4-D removal in the PSPC was lower than that in the PC. The aim of this study was to develop a new pulsed switching peroxi-coagulation system to control hydroxyl radical (∙OH) production and to enhance 2,4-Dichlorophenoxyacetic acid (2,4-D) degradation. The system was constructed with a sacrifice iron anode, a Pt anode, and a gas diffusion cathode. Production of H 2O 2 and Fe 2+ was controlled separately by time delayers with different pulsed switching frequencies. Under current densities of 5.0 mA/cm 2 (H 2O 2) and 0.5 mA/cm 2 (Fe 2+), the ∙OH production was optimized with the pulsed switching frequency of 1.0 s (H 2O 2):0.3 s (Fe 2+) and the ratio of H 2O 2 to Fe 2+ molar concentrations of 6.6. Under the optimal condition, 2,4-D with an initial concentration of 500 mg/L was completely removed in the system within 240 min. The energy consumption for the 2,4-D removal in the system was much lower than that in the electro-Fenton process (68±6 vs. 136±10 kWh/kg TOC). The iron consumption in the system was ~20 times as low as that in the peroxi-coagulation process (196±20 vs. 3940±400 mg/L) within 240 min. The system should be a promising peroxi-coagulation method for organic pollutants removal in wastewater.

Abstract This work studied the ability of Comamonas koreensis CY01 to reduce Fe(III) (hydr)oxides by coupling the oxidation of electron donors and the enhanced biodegradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by the presence of Fe(III) (hydr)oxides. The experimental results suggested that strain CY01 can utilize ferrihydrite, goethite, lepidocrocite or hematite as the terminal electron acceptor and citrate, glycerol, glucose or sucrose as the electron donor. Strain CY01 could transform 2,4-D to 4-chlorophenol through reductive side-chain removal and dechlorination. Under the anaerobic conditions, Fe(III) reduction and 2,4-D biodegradation by strain CY01 occurred simultaneously. The presence of Fe(III) (hydr)oxides would significantly enhance 2,4-D biodegradation, probably due to the fact that the reactive mineral-bound Fe(II) species generated from Fe(III) reduction can abiotically reduce 2,4-D. This is the first report of a strain of C. koreensis capable of reducing Fe(III) (hydr)oxides and 2,4-D, which extends the diversity of iron-reducing bacteria associated with dechlorination.

Currently, pJP4 is one of the best-known plasmids for the biodegradation of xenobiotics that mediate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D), which is associated with serious health and environmental risks. Although the sequencing and proposed theory of pJP4 formation occurred almost 20 years ago (2004), pJP4 is still the model object of many studies focused on the biodegradation of 2,4-D. The uniqueness of this plasmid is due to the presence of two evolutionarily distinct gene clusters, tfd [sub.I] and tfd [sub.II] , controlling the degradation of 2,4-D. Recent advances in plasmid biology, especially those concerning the characterization of new IncP-1 plasmids and the systematization of tfd gene cluster findings, serve as a basis for proposing new insights into the formation of the clusters’ architecture of the canonical plasmid, pJP4, and their distribution among other plasmids. In the present work, a comparative genomic and phylogenetic in silico study of plasmids with tfd [sub.I] and tfd [sub.II] clusters was carried out. The possible initial distribution patterns of tfd [sub.I] clusters among plasmids of different incompatibility groups (non-IncP-1) and tfd [sub.II] clusters among IncP-1 plasmids using the IS1071 -based composite transposon were revealed. A new theory on the formation of the architecture of the tfd [sub.I] and tfd [sub.II] clusters of pJP4 through sequential internal rearrangements, recombination, and ISJP4 insertion, is proposed. In addition, small gene clusters resulting from internal rearrangements of pJP4 (tfd [sub.II] SA and ORF31/32) served as fingerprints for exploring the distribution of tfd [sub.I] and tfd [sub.II] clusters. The revealed patterns and formulated theory extend the frontiers of plasmid biology and will be beneficial for understanding the role of plasmids in bacterial adaptation to xenobiotic-contaminated environments.

The development of artificial small-scale robotic swarms with nature-mimicking collective behaviors represents the frontier of research in robotics. While microrobot swarming under magnetic manipulation has been extensively explored, light-induced self-organization of micro- and nanorobots is still challenging. This study demonstrates the interaction-controlled, reconfigurable, reversible, and active self-assembly of TiO 2 /α-Fe 2 O 3 microrobots, consisting of peanut-shaped α-Fe 2 O 3 (hematite) microparticles synthesized by a hydrothermal method and covered with a thin layer of TiO 2 by atomic layer deposition (ALD). Due to their photocatalytic and ferromagnetic properties, microrobots autonomously move in water under light irradiation, while a magnetic field precisely controls their direction. In the presence of H 2 O 2 fuel, concentration gradients around the illuminated microrobots result in mutual attraction by phoretic interactions, inducing their spontaneous organization into self-propelled clusters. In the dark, clusters reversibly reconfigure into microchains where microrobots are aligned due to magnetic dipole-dipole interactions. Microrobots’ active motion and photocatalytic properties were investigated for water remediation from pesticides, obtaining the rapid degradation of the extensively used, persistent, and hazardous herbicide 2,4-Dichlorophenoxyacetic acid (2,4D). This study potentially impacts the realization of future intelligent adaptive metamachines and the application of light-powered self-propelled micro- and nanomotors toward the degradation of persistent organic pollutants (POPs) or micro- and nanoplastics. Microrobot collectives promise new functions beyond individuals’ capability. Here, nature-inspired reconfigurable self-assembly of microrobots was created, driven by their photocatalytic and magnetic properties, showing potential application in water purification.

The understanding and mitigation of the appearance of herbicide-resistant weeds have come to the forefront of study in the past decade, as the number of weed species that are resistant to one or more herbicide modes of action is on the increase. Historically, weed resistance to auxin herbicides has been rare, but examples, such as Kochia scoparia L. Schrad (kochia), have appeared, posing a challenge to conventional agricultural practices. Reports of dicamba-resistant kochia populations began in the early 1990s in areas where auxin herbicides were heavily utilized for weed control in corn and wheat cropping systems, and some biotypes are resistant to other auxin herbicides as well. We have further characterized the auxin responses of one previously reported dicamba-resistant biotype isolated from western Nebraska and found that it is additionally cross-resistant to other auxin herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D) and fluroxypyr. We have utilized transcriptome sequencing and comparison to identify a 2-nt base change in this biotype, which results in a glycine to asparagine amino acid change within a highly conserved region of an AUX/indole-3-acetic acid (IAA) protein, KsIAA16. Through yeast two-hybrid analysis, characterization of F2 segregation, and heterologous expression and characterization of the gene in Arabidopsis thaliana, we show that that the single dominant KsIAA16R resistance allele is the causal basis for dicamba resistance in this population. Furthermore, we report the development of a molecular marker to identify this allele in populations and facilitate inheritance studies. We also report that the resistance allele confers a fitness penalty in greenhouse studies.

• Auxin regulates almost every aspect of plant growth and development and is perceived by the TIR1/AFB auxin co-receptor proteins differentially acting in concert with specific Aux/IAA transcriptional repressors. Little is known about the diverse functions of TIR1/AFB family members in species other than Arabidopsis. • We created targeted OsTIR1 and OsAFB2–5 mutations in rice using CRISPR/Cas9 genome editing, and functionally characterized the roles of these five members in plant growth and development and auxinic herbicide resistance. • Our results demonstrated that functions of OsTIR1/AFB family members are partially redundant in grain yield, tillering, plant height, root system and germination. Ostir1, Osafb2 and Osafb4 mutants exhibited more severe phenotypes than Osafb3 and Osafb5. The Ostir1Osafb2 double mutant displays extremely severe defects in plant development. All five OsTIR1/AFB members interacted with OsIAA1 and OsIAA11 proteins in vivo. Root elongation assay showed that each Ostir1/afb2–5 mutant was resistant to 2,4-dichlorophenoxyacetic acid (2,4-D) treatment. Notably, only the Osafb4 mutants were strongly resistant to the herbicide picloram, suggesting that OsAFB4 is a unique auxin receptor in rice. • Our findings demonstrate similarities and specificities of auxin receptor TIR1/AFB proteins in rice, and could offer the opportunity to modify effective herbicide-resistant alleles in agronomically important crops.

Moso bamboo ( Phyllostachys edulis ) is the most important monopodial bamboo species worldwide. Without a genetic transformation system, it is difficult to verify the functions of genes controlling important traits and conduct molecular breeding in moso bamboo. Here, we established a plant regeneration system from immature embryos. Calli were induced on MS medium added 4–6 mg⋅L –1 2,4-dichlorophenoxyacetic acid (2,4-D) with high efficiency (>60%). A plant growth regulator combination of 0.5 mg⋅L –1 1-naphthylacetic acid (NAA), 2.0 mg⋅L –1 6-benzylaminopurine (BAP), and 3.0 mg⋅L –1 zeatin (ZT) was suitable for shoot differentiation, and the shoot induction frequency was increased to 43% after 0.5 mg⋅L –1 abscisic acid (ABA) pretreatment. An effective antibiotic screening concentration was determined by hygromycin sensitivity test. We further optimized the Agrobacterium concentration and added vacuum infiltration for infection, which improves the transient expression efficiency. A genetic transformation system was established for the first time in moso bamboo, with the transformation efficiency of approximately 5%. To optimize genome editing, two endogenous U3 small nuclear RNA (snRNA) promoters were isolated and used to drive small guide RNA (sgRNA) expression. The results showed that the PeU3.1 promoter exhibited higher efficiency, and it was used for subsequent genome editing. Finally, homozygous pds1pds2 mutants were obtained by an efficient CRISPR/Cas9 genome-editing system. These technical systems will be conducive to gene functional validation and accelerate the molecular breeding process of moso bamboo.

Herbicides are the most used class of pesticides worldwide, and insect repellents are widely used globally. Yet, there is a dearth of studies characterizing the associations between these chemical groups and human neurobehavior. Experimental studies suggest that glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) herbicides can affect neurobehavior and the cholinergic and glutamatergic pathways in the brain. We aim to assess whether herbicides and insect repellents are associated with neurobehavioral performance in adolescents. We assessed 519 participants (11-17 years of age) living in agricultural communities in Ecuador. We quantified urinary concentrations of glyphosate, 2,4-D, and two N,N-diethyl-meta-toluamide (DEET) insect repellent metabolites [3-(diethylcarbamoyl)benzoic acid (DCBA) and 3-(ethylcarbamoyl)benzoic acid (ECBA)] using isotope-dilution mass spectrometry. We assessed neurobehavioral performance using 9 subtests across 5 domains (attention/inhibitory control, memory/learning, language, visuospatial processing, and social perception). We characterized the associations using generalized estimating equations and multiple imputation for metabolites below detection limits. Models were adjusted for demographic and anthropometric characteristics, urinary creatinine, and sexual maturation. Mediation by salivary cortisol, dehydroepiandrosterone, , and testosterone was assessed using structural equation modeling. The mean of each neurobehavioral domain score was between 7.0 and 8.7 [standard deviation (SD) range: 2.0-2.3]. Glyphosate was detected in 98.3% of participants, 2,4-D in 66.2%, DCBA in 63.3%, and ECBA in 33.4%. 2,4-D was negatively associated with all neurobehavioral domains, but statistically significant associations were observed with attention/inhibition [score difference per 50% higher metabolite concentration 95% confidence interval (CI): , ], language [ (95% CI: , )], and memory/learning [ (95% CI: , 0.01)]. Glyphosate had a statistically significant negative association only with social perception [ (95% CI: , )]. DEET metabolites were not associated with neurobehavioral performance. Mediation by gender and adrenal hormones was not observed. This study describes worse neurobehavioral performance associated with herbicide exposures in adolescents, particularly with 2,4-D. Replication of these findings among other pediatric and adult populations is needed. https://doi.org/10.1289/EHP11383.