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Lookup NU author(s): George Giannakopoulos,
Professor Robert Edwards
This is the authors' accepted manuscript of an article that has been published in its final definitive form by John Wiley and Sons Ltd, 2020.
For re-use rights please refer to the publisher's terms and conditions.
© 2020 Society of Chemical Industry. BACKGROUND: Safeners extend the application of existing herbicides by selectively enhancing tolerance in large-grained cereal crops. While their activity is linked to enhanced herbicide metabolism, their exact mode of action and reasons for their crop specificity have yet to be determined. In this study, we investigated the selectivity of the recently developed sulfonamide safener cyprosulfamide (CSA) in maize (Zea mays L.) and wheat (Triticum aestivum), focusing on its uptake, distribution and metabolism in the two species. RESULTS: CSA protected maize, but not wheat, from injury by thiencarbazone-methyl (TCM). This correlated with the selective enhanced detoxification of the herbicide in maize. CSA underwent more rapid metabolism in maize than in wheat, with the formation of a specific hydroxylated metabolite correlating with safening. Studies with the nsf1 mutant sweetcorn line showed that the hydroxylation of CSA was partly mediated by the cytochrome P450 CYP81A9. However, primary metabolites of CSA were chemically synthesised and tested for their ability to safen TCM in maize but when tested were inactive as safeners. CONCLUSION: The results of this study suggest that the protection against TCM injury by CSA is linked to enhanced herbicide metabolism. This selective activity is due to the specific recognition of parent CSA in maize but not in wheat. Subsequent rapid oxidative metabolism of CSA led to its inactivation, demonstrating that cytochrome P450s regulate the activity of safeners as well as herbicides. © 2020 Society of Chemical Industry.
Author(s): Giannakopoulos G, Dittgen J, Schulte W, Zoellner P, Helmke H, Lagojda A, Edwards R
Publication type: Article
Publication status: Published
Journal: Pest Management Science
Print publication date: 01/10/2020
Online publication date: 21/02/2020
Acceptance date: 21/02/2020
Date deposited: 08/04/2020
ISSN (print): 1526-498X
ISSN (electronic): 1526-4998
Publisher: John Wiley and Sons Ltd
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