Biosynthesis of (+)-abscisic acid in Cercospora cruenta.

Abstract

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