Accumulation of dehydrofusaric acid and its conversion to fusaric and 10-hydroxyfusaric acids in cultures of Gibberella fujikuroi

Gibberella fujikuroi (Saw.) Wr. strain 917 produced dehydrofusaric acid in high yield when cultured in a defined medium containing adequate nitrogen. The metabolite was separated by partition chromatography from the small amount of fusaric acid present. Fusaric and dehydrofusaric acids can be interconverted by the culture since radioactivity administered as either 14C-labeled fusaric acid or 14C-labeled dehydrofusaric acid was distributed into both metabolites. Radioactivity also accumulated in more polar substances. These were isolated from cultures administered acetate-2-14C and the main radioactive product was identified as 10-hydroxyfusaric acid. 11-Chloro-10-hydroxyfusaric acid was tentatively identified in the culture extract, but may be an artifact.