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Reversing resistance to tembotrione in an Amaranthus tuberculatus (var. rudis) population from Nebraska, USA with cytochrome P450 inhibitors

Oliveira, Maxwel C, Gaines, Todd A, Dayan, Franck E, Patterson, Eric L, Jhala, Amit J, Knezevic, Stevan Z
Pest management science 2018 v.74 no.10 pp. 2296-2305
4-hydroxyphenylpyruvate dioxygenase, Amaranthus tuberculatus, amitrole, corn, cytochrome P-450, genes, malathion, mesotrione, metabolism, piperonyl butoxide, soybeans, tembotrione, topramezone, weed control, Nebraska
BACKGROUND: A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4‐hydroxyphenylpyruvate dioxygenase (HPPD)‐inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non‐target‐site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors in restoring the efficacy of HPPD‐inhibitor herbicides on the HPPD‐inhibitor resistant A. tuberculatus population from Nebraska, USA (HPPD‐R). RESULTS: Enhanced metabolism via cytochrome P450 enzymes is the mechanism of resistance in HPPD‐R. Amitrole partially restored the activity of mesotrione, whereas malathion, amitrole, and piperonyl butoxide restored the activity of tembotrione and topramezone in HPPD‐R. Although corn was injured through malathion followed by mesotrione application a week after treatment, the injury was transient, and the crop recovered. CONCLUSION: The use of cytochrome P450 inhibitors with tembotrione may provide a new way of controlling HPPD‐inhibitor resistant A. tuberculatus, but further research is needed to identify the cytochrome P450 candidate gene(s) conferring metabolism‐based resistance. The results presented here aid to gain an insight into non‐target‐site resistance weed management strategies. © 2017 Society of Chemical Industry