Inhibition profile of trifludimoxazin towards PPO2 target site mutations

Aimone Porri, Michael Betz, Kathryn Seebruck, Michael Knapp, Philipp Johnen, Matthias Witschel, Raphael Aponte, Rex Liebl, Patrick J. Tranel, Jens Lerchl

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Target site resistance to herbicides that inhibit protoporphyrinogen IX oxidase (PPO; EC 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.

Original languageEnglish (US)
Pages (from-to)507-519
Number of pages13
JournalPest Management Science
Issue number2
StatePublished - Feb 2023


  • PPO
  • efficacy
  • herbicide
  • herbicide resistance
  • mutations
  • target site
  • trifludimoxazin

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Insect Science


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