Biosynthesis of chloroplastidic and extrachloroplastidic terpenoids in liverwort cultured cells:: 13C serine as a probe of terpene biosynthesis via mevalonate and non-mevalonate pathways

Two terpenoid biosynthetic pathways, the inevalonate and non-mevalonate (glyceraldehyde phosphate-pyruvate) routes, were examined by feeding C-13-labeled serines ([1-C-13]- and [3-C-13]-) to the cultured cells of the liverwort, Heteroscyphus planus. The labeling patterns observed in the isoprenoid unit of the biosynthetically C-13-labeled stigmasterol corresponded to those expected from the mevalonate pathway, while those of the phytyl side chain corresponded to those from the non-mevalonate pathway. Thus, serine is a potential probe to determine the origin of terpenoid biosynthesis, in either the inevalonate or noninevalonate pathway.