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. 1991 Sep;97(1):197–203. doi: 10.1104/pp.97.1.197

Effect of Diphenyl Ether Herbicides on Oxidation of Protoporphyrinogen to Protoporphyrin in Organellar and Plasma Membrane Enriched Fractions of Barley 1

Judith M Jacobs 1,2, Nicholas J Jacobs 1,2, Timothy D Sherman 1,2, Stephen O Duke 1,2
PMCID: PMC1080984  PMID: 16668371

Abstract

In barley (Hordeum vulgare L.) root cells, activity for oxidizing protoporphyrinogen to protoporphyrin (protoporphyrinogen oxidase), a step in chlorophyll and heme synthesis, was found both in the crude mitochondrial fraction and in a plasma membrane enriched fraction separated by a sucrose gradient technique utilized for preparing plasma membranes. The specific activity (expressed as nanomoles of protoporphyrin formed per hour per milligram protein) in the mitochondrial fraction was 8 and in the plasma membrane enriched fraction was 4 to 6. The plasma membrane enriched fraction exhibited minimal cytochrome oxidase activity and no carotenoid content, indicating little contamination with mitochondrial or plastid membranes. Etioplasts from etiolated barley leaves exhibited a protoporphyrinogen oxidase specific activity of 7 to 12. Protoporphyrinogen oxidase activity in the barley root mitochondrial fraction and etioplast extracts was more than 90% inhibited by assay in the presence of the diphenyl ether herbicide acifluorfen methyl, but the activity in the plasma membrane enriched fraction exhibited much less inhibition by this herbicide (12 to 38% inhibition) under the same assay conditions. Acifluorfen-methyl inhibition of the organellar (mitochondrial or plastid) enzyme was maximal upon preincubation of the enzyme with 4 mm dithiothreitol, although a lesser degree of inhibition was noted if the organellar enzyme was preincubated in the presence of other reductants such as glutathione or ascorbate. Acifluorfen-methyl caused only 20% inhibition if the enzyme was preincubated in buffer without reductants. Incubation of barley etioplast extracts with the earlier tetrapyrrole precursor coproporphyrinogen and acifluorfen-methyl resulted in the accumulation of protoporphyrinogen, which could be converted to protoporphyrin even in the presence of the herbicide by the addition of the plasma membrane enriched fraction from barley roots. These findings have implications for the toxicity of diphenyl ether herbicides, whose light induced tissue damage is apparently caused by accumulation of the photoreactive porphyrin intermediate, protoporphyrin, when the organellar protoporphyrinogen oxidase enzyme is inhibited by herbicides. Our results suggest that the protoporphyrinogen that accumulates as a result of herbicide inhibition of the organellar enzyme can be oxidized to protoporphyrin by a protoporphyrinogen oxidizing activity that is located at sites such as the plasma membrane, which is much less sensitive to inhibition by diphenylether herbicides.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Becerril J. M., Duke S. O. Protoporphyrin IX Content Correlates with Activity of Photobleaching Herbicides. Plant Physiol. 1989 Jul;90(3):1175–1181. doi: 10.1104/pp.90.3.1175. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bowyer J. R., Hallahan B. J., Camilleri P., Howard J. Mode of Action Studies on Nitrodiphenyl Ether Herbicides : II. The Role of Photosynthetic Electron Transport in Scenedesmus obliquus. Plant Physiol. 1989 Feb;89(2):674–680. doi: 10.1104/pp.89.2.674. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Camadro J. M., Matringe M., Scalla R., Labbe P. Kinetic studies on protoporphyrinogen oxidase inhibition by diphenyl ether herbicides. Biochem J. 1991 Jul 1;277(Pt 1):17–21. doi: 10.1042/bj2770017. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Hodges T. K., Leonard R. T. Purification of a plasma membrane-bound adenosine triphosphatase from plant roots. Methods Enzymol. 1974;32:392–406. doi: 10.1016/0076-6879(74)32039-3. [DOI] [PubMed] [Google Scholar]
  5. Jacobs J. M., Jacobs N. J., Borotz S. E., Guerinot M. L. Effects of the photobleaching herbicide, acifluorfen-methyl, on protoporphyrinogen oxidation in barley organelles, soybean root mitochondria, soybean root nodules, and bacteria. Arch Biochem Biophys. 1990 Aug 1;280(2):369–375. doi: 10.1016/0003-9861(90)90344-x. [DOI] [PubMed] [Google Scholar]
  6. Jacobs J. M., Jacobs N. J., De Maggio A. E. Protoporphyrinogen oxidation in chloroplasts and plant mitochondria, a step in heme and chlorophyll synthesis. Arch Biochem Biophys. 1982 Oct 1;218(1):233–239. doi: 10.1016/0003-9861(82)90341-1. [DOI] [PubMed] [Google Scholar]
  7. Jacobs J. M., Jacobs N. J. Oxidation of protoporphyrinogen to protoporphyrin, a step in chlorophyll and haem biosynthesis. Purification and partial characterization of the enzyme from barley organelles. Biochem J. 1987 May 15;244(1):219–224. doi: 10.1042/bj2440219. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Jacobs N. J., Borotz S. E., Jacobs J. M. Characteristics of purified protoporphyrinogen oxidase from barley. Biochem Biophys Res Commun. 1989 Jun 15;161(2):790–796. doi: 10.1016/0006-291x(89)92669-7. [DOI] [PubMed] [Google Scholar]
  9. Jacobs N. J., Jacobs J. M. Assay for enzymatic protoporphyrinogen oxidation, a late step in heme synthesis. Enzyme. 1982;28(2-3):206–219. doi: 10.1159/000459103. [DOI] [PubMed] [Google Scholar]
  10. Little H. N., Jones O. T. The subcellular loclization and properties of the ferrochelatase of etiolated barley. Biochem J. 1976 May 15;156(2):309–314. doi: 10.1042/bj1560309. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Matringe M., Camadro J. M., Labbe P., Scalla R. Protoporphyrinogen oxidase as a molecular target for diphenyl ether herbicides. Biochem J. 1989 May 15;260(1):231–235. doi: 10.1042/bj2600231. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Matringe M., Camadro J. M., Labbe P., Scalla R. Protoporphyrinogen oxidase inhibition by three peroxidizing herbicides: oxadiazon, LS 82-556 and M&B 39279. FEBS Lett. 1989 Mar 13;245(1-2):35–38. doi: 10.1016/0014-5793(89)80186-3. [DOI] [PubMed] [Google Scholar]
  13. Matringe M., Scalla R. Studies on the mode of action of acifluorfen-methyl in nonchlorophyllous soybean cells : accumulation of tetrapyrroles. Plant Physiol. 1988 Feb;86(2):619–622. doi: 10.1104/pp.86.2.619. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Varsano R., Matringe M., Magnin N., Mornet R., Scalla R. Competitive interaction of three peroxidizing herbicides with the binding of [3H]acifluorfen to corn etioplast membranes. FEBS Lett. 1990 Oct 15;272(1-2):106–108. doi: 10.1016/0014-5793(90)80459-v. [DOI] [PubMed] [Google Scholar]
  15. Witkowski D. A., Halling B. P. Accumulation of photodynamic tetrapyrroles induced by acifluorfen-methyl. Plant Physiol. 1988 Jul;87(3):632–637. doi: 10.1104/pp.87.3.632. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Witkowski D. A., Halling B. P. Inhibition of plant protoporphyrinogen oxidase by the herbicide acifluorfen-methyl. Plant Physiol. 1989 Aug;90(4):1239–1242. doi: 10.1104/pp.90.4.1239. [DOI] [PMC free article] [PubMed] [Google Scholar]

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