Metabolic Pathways forS-Metolachlor Detoxification Differ Between Tolerant Corn and Multiple-Resistant Waterhemp
| Autor: | Nicholas J Seiter, Seth A. Strom, Aaron G. Hager, Jeanaflor Crystal T. Concepcion, Shiv S. Kaundun, James Morris, Adam S. Davis, Dean E. Riechers |
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| Rok vydání: | 2021 |
| Předmět: |
Physiology
Metabolite Weed resistance Plant Weeds Cytochrome P450 Plant Science AcademicSubjects/SCI01180 Zea mays chemistry.chemical_compound Xenobiotic detoxification Acetamides Regular Paper chemistry.chemical_classification Amaranthus biology AcademicSubjects/SCI01210 Herbicide metabolism Herbicides Cell Biology General Medicine Monooxygenase biology.organism_classification Enzyme assay Glutathione S-transferase Metabolic pathway Enzyme chemistry Biochemistry biology.protein Amaranthus tuberculatus Metabolic Networks and Pathways Herbicide Resistance |
| Zdroj: | Plant and Cell Physiology |
| ISSN: | 1471-9053 0032-0781 |
| Popis: | Herbicide resistance in weeds can be conferred by target-site and/or non-target-site mechanisms, such as rapid metabolic detoxification. Resistance to the very-long-chain fatty acid–inhibiting herbicide, S-metolachlor, in multiple herbicide-resistant populations (CHR and SIR) of waterhemp (Amaranthus tuberculatus) is conferred by rapid metabolism compared with sensitive populations. However, enzymatic pathways for S-metolachlor metabolism in waterhemp are unknown. Enzyme assays using S-metolachlor were developed to determine the specific activities of glutathione S-transferases (GSTs) and cytochrome P450 monooxygenases (P450s) from CHR and SIR seedlings to compare with tolerant corn and sensitive waterhemp (WUS). GST activities were greater (∼2-fold) in CHR and SIR compared to WUS but much less than corn. In contrast, P450s in microsomal extracts from CHR and SIR formed O-demethylated S-metolachlor, and their NADPH-dependent specific activities were greater (>20-fold) than corn or WUS. Metabolite profiles of S-metolachlor generated via untargeted and targeted liquid chromatography–mass spectrometry from CHR and SIR differed from WUS, with greater relative abundances of O-demethylated S-metolachlor and O-demethylated S-metolachlor-glutathione conjugates formed by CHR and SIR. In summary, our results demonstrate that S-metolachlor metabolism in resistant waterhemp involves Phase I and Phase II metabolic activities acting in concert, but the initial O-demethylation reaction confers resistance. |
| Databáze: | OpenAIRE |
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