 Fusicoccin was and is extensively used in research regarding the plant hormone auxin and its mechanisms.Fusicoccin is a member of a diterpenoid class which shares a 5-8-5 ring structure and is called fusicoccane.In fungi, fusicoccin is biosynthesized via "Phomopsis amygdali" fusicoccadiene synthase (PaFS) from universal C5 isoprene units dimethylallyl diphosphate (DMAPP) and isopentenyl diphosphate (IPP).