Labeling Patterns of Chloroplastidic Isoprenoids in Cultured Cells of Liverwort Ptychanthus striatus

Abstract

Incorporation studies administering ²H- and ¹³C- labeled mevalonate (MVA) and ¹³C-labeled glucose to suspension cultured cells of the liverwort, Ptychanthus striatus, were carried out in order to examine the biosynthesis of the phytyl side-chain of chlorophyll a. Administration of ¹³C- and ²H-labeled MVA provided evidence for the involvement of the MVA pathway in the phytyl side-chain biosynthesis and preferential labeling of the farnesyl diphosphate (FPP)-derived portion. An alternate labeling pattern in the phytyl side-chain was observed which was slightly different to the nonequivalent labeling in other liverworts, such as Heteroscyphus planus and Lophocolea heterophylla and in the hornwort, Anthoceros punctatus. The labeling pattern observed after the administration of ¹³C-labeled glucose revealed the simultaneous involvement of the non-MVA pathway in the phytol biosynthesis of P. striatus cells.