Functional identification of a rice ent-kaurene oxidase, OsKO2, using the Pichia pastoris expression system

Abstract

Rice ent-kaurene oxidase 2 (OsKO2) perhaps functions in the early steps of gibberellin biosynthesis. We found that microsomes from the methylotropic yeast Pichia pastoris expressing both OsKO2 and a fungal cytochrome P450 monooxygenase (P450) reductase converted ent-kaurene to ent-kaurenoic acid. This is direct evidence that OsKO2 is involved in the sequential oxidation of ent-kaurene to ent-kaurenoic acid in gibberellin biosynthesis in rice.