Fig. 3. Discovery of a diaboline, strychnine and brucine biosynthesis pathway.
a, The complete biosynthetic pathway leading to the production of diaboline 8, strychnine 10 and brucine 15. Diamonds represent intermediates detected in S. nux-vomica (Extended Data Fig. 10). b, The liquid chromatography–mass spectrometry peak area of products produced in N. benthamiana after expression of the indicated enzymes and geissoschizine 1 infiltration. Date are mean ± s.e.m.; n = 3 biological replicates. c, The liquid chromatography–mass spectrometry peak area of products produced in N. benthamiana after expression of the indicated enzymes and strychnine 10 infiltration. Date are mean ± s.e.m.; n = 3 biological replicates. Work-up: manipulation after expression of the indicated enzymes and substrate infiltration. d, Extracted ion chromatograms (EIC) for strychnine 10, isostrychnine 11, β-colubrine 13 and brucine 15 in N. benthamiana leaves expressing all nine enzymes with the infiltration of geissoschizine 1 and disodium malonate. All intermediates were validated by comparison to synthetic authentic standards (see Supplementary Information for synthetic procedures).