Biosynthesis of (+)-Abscisic Acid in Cercospora cruenta

Abstract

(R)-[2-¹⁴C]-Mevalonic acid (MVA) lactone was incorporated into (-)-4'-hydroxy-γ-ionylideneacetic acid (4'-hydroxy-γ-acid), which was first isolated from the culture broth of Cercospora cruenta. 4'-Hydroxy-γ-was then metabolized to (+)-(2Z, 4E)-4'-oxo-α-ionylideneacetic acid and (+)-(2Z, 4E)-1', 4'-dihydroxy-γ-ionylideneacetic acid. The latter was converted to (+)-abscisic acid (ABA) with a high incorporation ratio by the fungus.