GC-MS total ion chromatogram (TIC) and MS spectra of major and minor pathway products from overexpression of HMGR, cytGGPPS, cytOsCPS4, cytOsKSL4, and CYP76M8 in N. benthamiana. Representative TICs are shown for the experimental sample and the no diterpene synthase control. Three total products with m/z corresponding to diterpene derived scaffolds were observed only upon expression of pathway genes. The major product identified corresponded to syn-pimaradien-6-ol and putative structures for two minor products were hypothesized (For syn-copalyl alcohol see Supplemental Figure 9, for *, corresponding to an endogenous metabolite, see Extended Data Figure 2). Putative ion structures for the major product were assigned as reference. Putative structures are preliminary and based on predicted chemical formulas combined with analysis of the fragment ions observed in the MS spectra.