Biosynthesis of trichothecenes and apotrichothecenes.
Fusarium culmorum produces two major trichothecenes, 3-acetyldeoxynivalenol and sambucinol, and some minor apotrichothecenes. It was desired to investigate if during their biosynthesis a C-11-keto intermediate was involved. To verify this postulate, trichodiene, a known precursor to trichothecenes, was synthesized with two deuteriums at C-11 and one at C-15. It was then fed to F. culmorum cultures, and the derived metabolites were purified and analyzed. The results ruled out the involvement of an 11-keto intermediate but revealed two novel apotrichothecenes. The characterization of their structures suggested that one of the 2-hydroxy-11alpha-apotrichothecene stereoisomers (2alpha or 2beta) could be converted to sambucinol. These apotrichothecenes were therefore synthesized labeled specifically with two deuteriums at C-4 and C-15 and fed to F. culmorum cultures. Indeed, the result established for the first time that 2alpha-hydroxy-11alpha-apotrichothecene was a precursor to sambucinol. A biosynthetic scheme for the production of trichothecenes and apotrichothecenes is described.
Zamir
L O
LO
Centre de Recherche en Microbiologie Appliquée, Université du Québec, Institut Armand-Frappier, Laval, Québec, Canada. Lolita_Zamir@iaf.uquebec.ca
Nikolakakis
A
A
Sauriol
F
F
Mamer
O
O
D003903:Deuterium; D005670:Fusarium / Q000378:metabolism*; D008956:Models, Chemical; D009183:Mycotoxins / Q000096:biosynthesis / Q000737:chemistry; D011198:Solanum tuberosum; D014255:Trichothecenes / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
D009183:Mycotoxins; D014255:Trichothecenes; C043247:3-acetyldeoxynivalenol; C054183:sambucinol; D003903:Deuterium