Diterpene synthesis in Stevia rebaudiana: recruitment and up‐regulation of key enzymes from the gibberellin biosynthetic pathway

摘要: Stevia rebaudiana Bertoni leaves accumulate a mixture of at least eight different glycosides derived from the tetracyclic diterpene steviol. These natural products taste intensely sweet and have similar biosynthetic origins to those gibberellic acid (GA). The initial steps leading formation GA result two-step cyclization geranylgeranyl diphosphate (GGDP) (-)-kaurene via action two terpene cyclases (-)-copalyl synthase (CPS) (KS). Steviol biosynthesis probably uses same mechanism although genes enzymes S. that are involved in GGDP not been characterized. We isolated both CPS KS found recombinant were catalytically active, suggesting participate steviol biosynthesis. coding for usually present single copies most plant species their expression is normally low limited rapidly growing tissues. gene has duplicated genome highly expressed mature leaves, pattern opposite with This may, part, lead temporal spatial separation helps prevent over-expression interfering normal metabolism. Our results show part glycoside pathway recruited secondary metabolism regulated hormone