title: Enzymatic basis for fungicide removal by Elodea canadensis.
abstract: OBJECTIVE
  Plants can absorb a diversity of natural and man-made toxic compounds for which they have developed diverse detoxification mechanisms. Plants are able to metabolize and detoxify a wide array of xenobiotics by oxidation, sugar conjugation, glutathione conjugation, and more complex reactions. In this study, detoxification mechanisms of dimethomorph, a fungicide currently found in aquatic media were investigated in Elodea canadensis.
  
  
  METHODS
  Cytochrome P450 (P450) activity was measured by an oxygen biosensor system, glucosyltransferases (GTs) by HPLC, glutathione S-transferases (GSTs), and ascorbate peroxidase (APOX) were assayed spectrophotometrically.
  
  
  RESULTS
  Incubation of Elodea with dimethomorph induced an increase of the P450 activity. GST activity was not stimulated by dimethomorph suggesting that GST does not participate in dimethomorph detoxification. In plants exposed to dimethomorph, comparable responses were observed for GST and APOX activities showing that the GST was more likely to play a role in response to oxidative stress. Preincubation with dimethomorph induced a high activity of O- and N-GT, it is therefore likely that both enzymes participate in the phase II (conjugation) of dimethomorph detoxification process.
  
  
  CONCLUSIONS
  For the first time in aquatic plants, P450 activity was shown to be induced by a fungicide suggesting a role in the metabolization of dimethomorph. Moreover, our finding is the first evidence of dimethomorph and isoproturon activation of cytochrome P450 multienzyme family in an aquatic plant, i.e., Elodea (isoproturon was taken here as a reference molecule). The detoxification of dimetomorph seems to proceed via hydroxylation, and subsequent glucosylation, and might yield soluble as well as cell wall bound residues.
authors.affiliation: Laboratoire Plantes, Pesticides et Développement Durable (PPDD), URVVC-SE EA 2069, Université de Reims Champagne-Ardenne, BP 1039, 51687 Reims Cedex 2, France. rachel.olette@gmail.com
authors.forename: Rachel
authors.initials: R
authors.lastname: Dosnon-Olette
authors.forename: Peter
authors.initials: P
authors.lastname: Schröder
authors.forename: Bernadett
authors.initials: B
authors.lastname: Bartha
authors.forename: Aziz
authors.initials: A
authors.lastname: Aziz
authors.forename: Michel
authors.initials: M
authors.lastname: Couderchet
authors.forename: Philippe
authors.initials: P
authors.lastname: Eullaffroy
mesh_terms: D060387:Ascorbate Peroxidases; D001673:Biodegradation, Environmental; D015374:Biosensing Techniques; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000378:metabolism; D005659:Fungicides, Industrial / Q000032:analysis*; D005964:Glucosyltransferases / Q000032:analysis / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000032:analysis / Q000378:metabolism; D031321:Hydrocharitaceae / Q000201:enzymology* / Q000254:growth & development; D009025:Morpholines / Q000302:isolation & purification* / Q000378:metabolism; D018384:Oxidative Stress; D010544:Peroxidases / Q000032:analysis / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000302:isolation & purification* / Q000378:metabolism; D015262:Xenobiotics / Q000493:pharmacokinetics*
chemical_list: D005659:Fungicides, Industrial; D009025:Morpholines; D014874:Water Pollutants, Chemical; D015262:Xenobiotics; C076154:dimethomorph; D003577:Cytochrome P-450 Enzyme System; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D005964:Glucosyltransferases; D005982:Glutathione Transferase; D005978:Glutathione