Heteromerization of Short-Chain trans-Prenyltransferase Controls Precursor Allocation within a Plastidial Terpenoid Network.

Terpenes are the largest and most diverse class of plant specialized metabolites. Sesterterpenes (C25), which are derived from the plastid methylerythritol phosphate (MEP) pathway, were recently characterized in plants. In Arabidopsis thaliana, four genes encoding GFPPS (AtGFPPS1 to 4) are responsible for the production of GFPP, which is the common precursor for sesterterpene biosynthesis. However, the interplay between sesterterpenes and other known terpenes remain elusive. Here, we first provide genetic evidence to demonstrate that GFPPSs are responsible for sesterterpene production in Arabidopsis. Blockage of the sesterterpene pathway at GFPPS step increased the production of GGPP-derived terpenes. Interestingly, coexpression of sesterTPSs in GFPPS-OE plants rescued the phenotypic changes of GFPPS-OE plants by restoring the endogenous GGPP. We further demonstrated that, in addition to precursor (DMAPP/IPP) competition by GFPPS and GGPPS in plastids, GFPPS directly decreased the activity of GGPPS through protein-protein interaction, ultimately leading to GGPP deficiency in planta. Our study provides a new regulatory mechanism of the plastidial terpenoid network in plant cells. This article is protected by copyright. All rights reserved.