Main content area

Hydroxylation of Longiborneol by a Clm2-Encoded CYP450 Monooxygenase to Produce Culmorin in Fusarium graminearum

Bahadoor, Adilah, Schneiderman, Danielle, Gemmill, Larissa, Bosnich, Whynn, Blackwell, Barbara, Melanson, Jeremy E., McRae, Garnet, Harris, Linda J.
Journal of natural products 2016 v.79 no.1 pp. 81-88
Fusarium graminearum, X-ray diffraction, biosynthesis, cytochrome P-450, hydroxylation, light scattering, mutants, nuclear magnetic resonance spectroscopy, plant pathogens, secondary metabolites, stereochemistry, structural genes
A second structural gene required for culmorin biosynthesis in the plant pathogen Fusarium graminearum is described. Clm2 encodes a regio- and stereoselective cytochrome P450 monooxygenase for C-11 of longiborneol (1). Clm2 gene disruptants were grown in liquid culture and assessed for culmorin production via HPLC-evaporative light scattering detection. The analysis indicated a complete loss of culmorin (2) from the liquid culture of the ΔClm2 mutants. Culmorin production resumed in a ΔClm2 complementation experiment. A detailed analysis of the secondary metabolites extracted from the large-scale liquid culture of disruptant ΔClm2D20 revealed five new natural products: 3-hydroxylongiborneol (3), 5-hydroxylongiborneol (4), 12-hydroxylongiborneol (5), 15-hydroxylongiborneol (6), and 11-epi-acetylculmorin (7). The structures of the new compounds were elucidated by a combination of HRMS, 1D and 2D NMR, and X-ray crystallography.