Resistance to a nonselective 4-hydroxyphenylpyruvate dioxygenase-inhibiting herbicide via novel reduction-dehydration-glutathione conjugation in Amaranthus tuberculatus.
New Phytol
; 232(5): 2089-2105, 2021 12.
Article
em En
| MEDLINE
| ID: mdl-34480751
ABSTRACT
Metabolic resistance to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides is a threat in controlling waterhemp (Amaranthus tuberculatus) in the USA. We investigated resistance mechanisms to syncarpic acid-3 (SA3), a nonselective, noncommercial HPPD-inhibiting herbicide metabolically robust to Phase I oxidation, in multiple-herbicide-resistant (MHR) waterhemp populations (SIR and NEB) and HPPD inhibitor-sensitive populations (ACR and SEN). Dose-response experiments with SA3 provided ED50 -based resistant sensitive ratios of at least 18-fold. Metabolism experiments quantifying parent SA3 remaining in excised leaves during a time course indicated MHR populations displayed faster rates of SA3 metabolism compared to HPPD inhibitor-sensitive populations. SA3 metabolites were identified via LC-MS-based untargeted metabolomics in whole plants. A Phase I metabolite, likely generated by cytochrome P450-mediated alkyl hydroxylation, was detected but was not associated with resistance. A Phase I metabolite consistent with ketone reduction followed by water elimination was detected, creating a putative α,ß-unsaturated carbonyl resembling a Michael acceptor site. A Phase II glutathione-SA3 conjugate was associated with resistance. Our results revealed a novel reduction-dehydration-GSH conjugation detoxification mechanism. SA3 metabolism in MHR waterhemp is thus atypical compared to commercial HPPD-inhibiting herbicides. This previously uncharacterized detoxification mechanism presents a unique opportunity for future biorational design by blocking known sites of herbicide metabolism in weeds.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Amaranthus
/
Dioxigenases
/
Herbicidas
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4-Hidroxifenilpiruvato Dioxigenase
Idioma:
En
Revista:
New Phytol
Assunto da revista:
BOTANICA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Estados Unidos