PubMed · 13512367
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R FABRE. 1957. Phytotoxicology.. https://pubmed.ncbi.nlm.nih.gov/13512367/
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BACKGROUND: Continuous use of glyphosate followed by glufosinate-ammonium has selected for multiple resistance to both herbicides in Eleusine indica worldwide. Managing such resistant weeds requires fast, accurate molecular detection assay. To address this critical need, we developed a robust multiplex TaqMan quantitative (q)PCR assay that simultaneously detects five well-characterized target-site resistance markers in E. indica: EPSPS copy number variation; T102I in EPSPS; P106A and P106S in EPSPS; and S59G in GS1-1. RESULTS: The multiplex qPCR assay showed analytical specificity when tested on genomic DNA from nine reference accessions: three susceptible, three glyphosate-resistant (with EPSPS CNV) and three multiple-resistant. Subsequent analysis of 56 field-collected samples demonstrated 98.2% concordance (55 of 56) with Sanger sequencing across all five resistance-associated markers: EPSPS CNV, T102I, P106A, P106S and GS1-1 S59G, confirming the reliability and practical value of the multiplex qPCR assay. Only samples 7-8 showed discordance at EPSPS position 102, where Sanger chromatograms showed overlapping peaks at this position, which is likely to be a result of heterozygous mutation distribution among amplified EPSPS gene copies. This case further underscores the advantages of the multiplex qPCR assay over Sanger sequencing in detection sensitivity and accuracy. Moreover, a strong correlation (R2 = 0.8935) in gene copy number estimation between the two methods across all samples further supports the reliability of the qPCR assay. CONCLUSIONS: In summary, this study delivers a simple, robust and high-throughput diagnostic tool for the rapid, simultaneous identification of dual herbicide target-site resistance in goosegrass, offering superior sensitivity, quantitative resolution and throughput compared with Sanger sequencing. © 2026 Society of Chemical Industry.
The extensive use of sulfonylurea herbicides has raised major concerns regarding their long-term soil residues and agroecological risks despite their role in agricultural protection. Microbial degradation is an important approach to remove sulfonylureas, whereas understanding the associated biodegradation mechanisms, enzymes, and physiological responses remains incomplete. Based on the rapid biodegradation of nicosulfuron by typical fungal isolate Talaromyces flavus LZM1, the dependency on cellular accumulation and environmental conditions, e.g. pH and nutrient supplies, was shown in the study. The biodegradation of nicosulfuron occurred intracellularly and followed the cascade of reactions including hydrolysis, Smile contraction rearrangement, hydroxylation, and opening of the pyrimidine ring. Besides 2-amino-4,6-dimethoxypyrimidine (ADMP) and 2-aminosulfonyl-N,N-dimethylnicotinamide (ASDM), numerous products and intermediates were newly identified and the structural forms of methoxypyrimidine and sulfonylurea bridge contraction rearrangement are predicted to be more toxic than nicosulfuron. The biodegradation should be enzymatically regulated by glycosylphosphatidylinositol transaminase (GPI-T) and P450s, which were manifested with the significant upregulation in proteomics. It is the first time that the hydrolysis of nicosulfuron into ADMP and ASDM have been associated with GPI-T. The integrated pathways of biodegradation were further elucidated through the involvement of various active enzymes. Except for the enzymatic catalysis, the physiological responses verified by metabolo-proteomics were critical not only to regulate material synthesis, uptake, utilization, and energy transfer but also to maintain antioxidant homeostasis, biodegradability, and tolerance of nicosulfuron by the differentially expressed metabolites, such as acetolactate synthase and 3-isopropylmalate dehydratase. The obtained results would help understand the biodegradation mechanism of sulfonylurea from chemicobiology and enzymology and promote the use of fungal biodegradation in pollution rehabilitation.
Uniformly-sized, molecularly imprinted polymers (MIPs) for atrazine, ametryn and irgarol were prepared by a multi-step swelling and polymerization method using ethylene glycol dimethacrylate as a cross-linker and methacrylic acid (MAA), 2-(trifluoromethyl) acrylic acid (TFMAA) or 4-vinylpyridine either as a functional monomer or not. The MIP for atrazine prepared using MAA showed good molecular recognition abilities for chlorotriazine herbicides, while the MIPs for ametryn and irgarol prepared using TFMAA showed excellent molecular recognition abilities for methylthiotriazine herbicides. A restricted access media-molecularly imprinted polymer (RAM-MIP) for irgarol was prepared followed by in situ hydrophilic surface modification using glycerol dimethacrylate and glycerol monomethacrylate as hydrophilic monomers. The RAM-MIP was applied to selective pretreatment and enrichment of methylthiotriazine herbicides, simetryn, ametryn and prometryn, in river water, followed by their separation and UV detection via column-switching HPLC. The calibration graphs of these compounds showed good linearity in the range of 50-500 pg/mL (r > 0.999) with a 100 mL loading of a river water sample. The quantitation limits of simetryn, ametryn and prometryn were 50 pg/mL, and the detection limits were 25 pg/mL. The recoveries of simetryn, ametryn and prometryn at 50 pg/mL were 101%, 95.6% and 95.1%, respectively. This method was successfully applied for the simultaneous determination of simetryn, ametryn and prometryn in river water.