Comparison between Biosynthesis of ent-Kaurene in Germinating Tomato Seeds and Cell Suspension Cultures of Tomato and Tobacco

Abstract

Biosynthesis of ent-kaurene was investigated in extracts of cell suspension cultures derived from tobacco callus (Nicotiana tabacum L.), tomato callus (Solanum lycopersicum L.), and in germinating tomato seeds. Incubation of extracts derived from the two cell cultures with either isopentenyl pyrophosphate-¹⁴C or with ¹⁴C-labeled mevalonate, followed by alkaline phosphatase hydrolysis, resulted in the formation of trans-geranylgeraniol-¹⁴C and trans-farnesol-¹⁴C. The corresponding pyrophosphates of trans-geranyl-geraniol-¹⁴C and trans-farnesol-¹⁴C were also detected. No detectable amount of ent-kaurene-¹⁴C was produced by these enzymatic preparations when trans-geranylgeranyl-¹⁴C pyrophosphate served as substrate. However, copalyl-¹⁴C pyrophosphate served as a substrate for the production of ent-kaurene. Cell-free extracts derived from germinating tomato seeds catalyzed the formation of ent-kaurene-¹⁴C from mevalonate-¹⁴C, isopentenyl-¹⁴C pyrophosphate, trans-geranylgeranyl-¹⁴C pyrophosphate, and copalyl-¹⁴C pyrophosphate.