Developmental pattern of Ginkgo biloba levopimaradiene synthase (GbLPS) as probed by promoter analysis in Arabidopsis thaliana.

Levopimaradiene synthase (GbLPS) of Ginkgo biloba catalyzes the first committed step in ginkgolide biosynthesis by converting geranylgeranyl diphosphate into levopimaradiene, which subsequently undergoes complex oxidation step and rearrangement of carbon skeleton, leading to formation of ginkgolides. To assess the organ-specificity and developmental characteristics of GbLPS expression, the GbLPS promoter-driven GUS expression in transgenic Arabidopsis was studied. Histological analysis of the transgenic Arabidopsis plant showed that the GUS accumulation was mainly localized in the epidermis of leaves, phloem of the shoots, ovaries and stamens of flowers, and vasculature of roots. These observations correlate with the occurrence of LPS transcripts in roots and male strobili of G. biloba. Treatment of methyl jasmonate on the transformant exhibited significant upregulation of the reporter gene in the roots with little change in leaves and flowers. The present findings support biosynthesis of ginkgolide in the roots of Ginkgo plant and suggest translocation occurs through the phloem.