Studies of clomazone mode of action

Yurdagul Ferhatoglu, Michael Barrett

Research output: Contribution to journalArticlepeer-review

93 Scopus citations


Intact spinach chloroplasts were used to determine if clomazone, 5-OH clomazone, and/or 5-keto clomazone inhibited the chloroplastic isoprenoid pathway. When isopentenyl pyrophosphate was used as a precursor, neither clomazone nor the clomazone metabolites (5-OH clomazone and 5-keto clomazone) inhibited the formation of products separated by HPLC in the organic phase. However, when pyruvate, a substrate for the first committed step of the pathway, was used as a precursor, both 5-keto clomazone and fosmidomycin reduced the formation of a non-polar product and increased the formation of a polar product in the organic phase. Only 5-keto clomazone, not 5-OH clomazone or clomazone, inhibited the formation of an additional product other than fosmidomycin in the aqueous phase from pyruvate incorporation. In an in vitro assay, 5-keto clomazone inhibited DXP synthase, the enzyme catalyzing the first committed step of the chloroplastic isoprenoid pathway. Therefore, our studies show that neither clomazone nor 5-OH clomazone inhibits the chloroplastic isoprenoid pathway, only 5-keto clomazone does.

Original languageEnglish
Pages (from-to)7-14
Number of pages8
JournalPesticide Biochemistry and Physiology
Issue number1
StatePublished - May 2006

Bibliographical note

Funding Information:
The authors thank Dr. Marc Clastre from the Laboratoire de Biologie Moleculaire et Biochimie Vegetale, Faculte de Pharmacie for providing the construct expressing C. roseus DXP synthase (XL1-blue/TCRDXS). This work was supported by the Higher Education Council of Turkey (YOK) fellowship to Y. Ferhatoglu and FMC Corp. grant.


  • 5-Keto clomazone
  • 5-OH clomazone
  • Carotenoid
  • Chlorophyll
  • Chloroplast
  • Clomazone
  • DXP synthase
  • IPP
  • MEP pathway

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Health, Toxicology and Mutagenesis


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