Biosynthesis of the trichothecene 3-acetyldeoxynivalenol. Is isotrichodermin a biosynthetic precursor?
3-Acetyldeoxynivalenol is the major trichothecene produced by the fungus Fusarium culmorum. The first proven tricyclic intermediate in the biosynthesis of 3-acetyldeoxynivalenol has been shown by in vivo studies to be isotrichodermin, a natural metabolite of F. culmorum. Indeed, the feeding of ring-deuterated isotrichodermin resulted in ring-deuterated 3-acetyldeoxynivalenol as shown by NMR studies. In this work, we have shown that the 3-acetyl group of isotrichodermin is mostly lost in its metabolism to 3-acetyldeoxynivalenol. We have shown by two different approaches that the deacetylation occurs at an early step after the first oxygenation step at C-15. Derivatives of isotrichodermin lacking the 3-acetyl such as 3-deacetyl isotrichodermin or 3-oxo-12,13-epoxytrichothec-9-ene are not precursors to 3-acetyldeoxynivalenol. The role of this acetyl exchange mechanism is not clear presently.
Centre de Recherche en Microbiologie Appliquée, Université du Québec, Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7.
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Zamir
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Nikolakakis
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Devor
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Sauriol
D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D003903:Deuterium; D005670:Fusarium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011865:Radioisotope Dilution Technique; D014255:Trichothecenes / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
D002250:Carbon Radioisotopes; D014255:Trichothecenes; C043247:3-acetyldeoxynivalenol; C063750:isotrichodermin; D003903:Deuterium