FAD-dependent monooxygenase; part of the gene cluster that mediates the biosynthesis of diterpenoid pyrones. The first step of the pathway is the synthesis of the alpha-pyrone moiety by the polyketide synthase dpfgA via condensation of one acetyl-CoA starter unit with 3 malonyl-CoA units and 2 methylations (Probable). The alpha-pyrone is then combined with geranylgeranyl pyrophosphate (GGPP) formed by the GGPP synthase dpfgD through the action of the prenyltransferase dpfgC to yield a linear alpha-pyrone diterpenoid (Probable). Subsequent steps in the diterpenoid pyrone biosynthetic pathway involve the decalin core formation, which is initiated by the epoxidation of the C10-C11 olefin by the FAD-dependent oxidoreductase dpfgE, and is followed by a cyclization cascade catalyzed by the terpene cyclase dpfgB (Probable). The short chain dehydrogenase/reductase dpfgG then oxidizes the 8S hydroxy group to a ketone and the short chain dehydrogenase/reductase dpfgH reduces the ketone to the 8R hydroxy group to yield higginsianin B. Higginsianin B is further methylated by the methyltransferase dpfgI to produce the intermediate named FDDP B. The cytochrome P450 monooxygenase dfgpJ then catalyzes a three-step oxidation at C-27 to generate a carboxylic acid as well as C-26 hydroxylation. Finally, methyltransferase dpfgK methylates the carboxylic acid generated by dpfgJ, yielding the final diterpenoid pyrones from the pathway which were named FDDP D and FDDP E