Inhibition profile of trifludimoxazin towards PPO2 target site mutations

• Published in: Pest management science Vol. 79; no. 2; pp. 507 - 519
• Main Authors: Porri, Aimone, Betz, Michael, Seebruck, Kathryn, Knapp, Michael, Johnen, Philipp, Witschel, Matthias, Aponte, Raphael, Liebl, Rex, Tranel, Patrick J., Lerchl, Jens
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.02.2023; Wiley Subscription Services, Inc
• Subjects: Arabidopsis; Arabidopsis - genetics; Chemical pest control; Complementation; E coli; Ectopic expression; efficacy; Enzymes; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; herbicide; Herbicide resistance; Herbicide Resistance - genetics; Herbicides; Herbicides - pharmacology; Inhibitors; Microorganisms; Mutants; Mutation; mutations; Oxidase; Pest control; Pest resistance; Plant Weeds - genetics; PPO; Protoporphyrinogen IX oxidase; Protoporphyrinogen Oxidase; target site; trifludimoxazin; Weeds; target site; mutations; herbicide; trifludimoxazin; herbicide resistance; PPO; efficacy
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.7216

BACKGROUND Target site resistance to herbicides that inhibit protoporphyrinogen IX oxidase (PPO; EC 1.3.3.4) has been described mainly in broadleaf weeds based on mutations in the gene designated protoporphyrinogen oxidase 2 (PPO2) and in one monocot weed species in protoporphyrinogen oxidase 1 (PPO1). To control PPO target site resistant weeds in future it is important to design new PPO‐inhibiting herbicides that can control problematic weeds expressing mutant PPO enzymes. In this study, we assessed the efficacy of a new triazinone‐type inhibitor, trifludimoxazin, to inhibit PPO2 enzymes carrying target site mutations in comparison with three widely used PPO‐inhibiting herbicides. RESULTS Mutated Amaranthus spp. PPO2 enzymes were expressed in Escherichia coli, purified and measured biochemically for activity and inhibition kinetics, and used for complementation experiments in an E. coli hemG mutant that lacks the corresponding microbial PPO gene function. In addition, we used ectopic expression in Arabidopsis and structural PPO protein modeling to support the enzyme inhibition study. The generated data strongly suggest that trifludimoxazin is a strong inhibitor both at the enzyme level and in transgenics Arabidopsis ectopically expressing PPO2 target site mutations. CONCLUSION Trifludimoxazin is a potent PPO‐inhibiting herbicide that inhibits various PPO2 enzymes carrying target site mutations and could be used as a chemical‐based control strategy to mitigate the widespread occurrence of PPO target site resistance as well as weeds that have evolved resistance to other herbicide mode of actions. © 2022 BASF SE and The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. Protoporphyrinogen IX oxidase (PPO)‐inhibiting herbicide resistance is mainly endowed by target site mutations. Amaranthus plants may contain more than one PPO target site mutation. Trifludimoxazin is effective in controlling PPO enzymes carrying double mutations.