Fig. 1: Proposed pathway for the biosynthesis of tropanol-derived alkaloids.

TRI tropine-forming reductase or tropinone reductase I, TRII pseudotropine-forming reductase or tropinone reductase II, LS littorine synthase, TS tigloidine synthase, the key finding of this study. The 3β-tropane alkaloid biosynthetic pathway is marked in blue, and the 3α-tropane alkaloid biosynthetic pathway is marked in green. P450-5021, 3β-tigloyloxytropane demethylase. P450-116623, tigloyl norpseudotropine hydroxylase.