Unraveling the Triterpenoid Saponin Biosynthesis of the African Shrub Maesa lanceolata

Maesasaponins produced by the African shrub Maesa lanceolata are oleanane-type saponins with diverse biological activities. Through a combination of transcript profiling of methyl jasmonate-elicited M. lanceolata shoot cultures, functional analysis in transgenic M. lanceolata plants and the heterologous hosts Medicago truncatula and Saccharomyces cerevisiae, we identified three maesaponin biosynthesis genes. These include a beta-amyrin synthase and two cytochrome P450s, CYP716A75 and CYP87D16, which catalyze the C-28 and C-16 alpha oxidations of b-amyrin, respectively.