Metabolic Engineering-Based Rapid Characterization of a Sesquiterpene Cyclase and the Skeletons of Fusariumdiene and Fusagramineol from Fusarium graminearum

The potential power of sesquiterpene synthase FgJ03939 from Fusarium graminearum was fully exploited in a farnesyl diphosphate-overexpressing Saccharomyces cerevisiae chassis to produce the novel sesquiterpenes fusariumdiene (1), epi-fusagramineol (2), and fusagramineol (3) with 5/7 bicyclic and 5/6/3 tricyclic ring systems, respectively, as well as five known sesquiterpenes (4–8). The structure of the unusual skeletons was characterized, and an absolute configuration was proposed. A mechanism for the biosynthesis of 1–8 was also proposed.