Fig. 5

Substrate-specificity of CYP71AU87. Shown are total ion chromatograms (TIC) and extracted ion chromatograms (EIC, individual mass ions) of reaction products resulting from transient N. benthamiana co-expression assays of CYP71AU87 with different class II and class diTPSs that produce distinct diterpenoid scaffolds. Tested products included the gibberellin precursor ent-kaurene 9 formed by the maize (Zea mays) ent-CPP synthase ZmAN2 and the ent-kaurene synthase GrEKS from Grindelia robusta [45], manoyl oxide 10 produced by the LPP synthase GrLPPS from G. robusta [23] and MvELS, and miltiradiene 11 formed by the (+)-CPP synthase IrTPS3 from Isodon rubescens [44] and MvELS. Co-expression of MvCPS1, MvELS and CYP71AU87 was used as a positive control. Mass spectra and structures of the formed diterpenoids are given in Additional file 7: Figure S5