Homeostasis of Isoprenoids in Plants: understanding compartmentalization, flux and transport of isoprenoids in glandular trichomes for non-crop and crop species
Plant Physiology
Final Report Abstract
Plants possess two pathways for the production of isoprenoid precursors, the mainly cytosolic mevalonate (MEV) pathway and the plastidial methylerythritol-phosphate (MEP) pathway. Both are essential because they are required for the synthesis of isoprenoids involved in respiration (ubiquinones), in photosynthesis (chlorophyll phytyl chain, plastoquinones, carotenoids), as hormones (brassinosteroids, gibberellins, strigolactones, abscisic acid), or membrane components (sterols). In addition, plants produce a variety of secondary isoprenoid metabolites, especially in dedicated organs such as oil glands, resin canals or glandular trichomes, where they can amount to very large quantities. Given the number of compounds produced from these pathways and the potential crosstalk between the MEP and MEV pathways, one major objective of the HIP project was to systematically localize the enzymes of these pathways, identify protein-protein interactions both within and outside the pathways, identify novel regulatory components of these pathways, and potential intracellular transporters to better understand the general regulation of these pathways and how isoprenoid homeostasis can be achieved to face these diverse needs. We chose tomato and tobacco as model systems since they are well-established plant models and also because they have glandular trichomes in which large quantities of terpenoid metabolites, either from the MEV or MEP pathway, are produced. All cDNAs of the MEV and MEP pathways from both plants were cloned and used to generate fusions with fluorescent proteins for subcellular localization, which was determined for all enzymes of the pathway. One notable discovery is the specific localization of DXS, the first step of the MEP pathway, to a distinct compartment of the plastids. The significance of this is unknown, but the fact that DXS was shown to be a key regulatory point of the MEP pathway could be connected to this. Protein-protein interaction studies revealed that mevalonate kinase (MVK), an enzyme of the MEV pathway forms dimers. Significant transcriptomics and proteomics data was produced from tomato and tobacco, including form leaves and trichomes, providing a rich dataset that can be mined for further studies. A tobacco line was generated which does not produce diterpenes in its trichomes any longer. This revealed a feedback mechanism at the transcript level both in the MEV and MEP pathway. Transcriptomics of this line provides leads for the identification of transcription factors that activate or repress specific genes of the MEP and MEV pathways.
Publications
- (2014). Comparative proteomics of short and tall glandular trichomes of Nicotiana tabacum reveals differential metabolic activities. Journal of Proteome Research 13, 3386–3396
Sallets A., Beyaert M., Boutry M. & Champagne A.
(See online at https://doi.org/10.1021/pr5002548) - Large-Scale Evolutionary Analysis of Genes and Supergene Clusters from Terpenoid Modular Pathways Provides Insights into Metabolic Diversification in Flowering Plants. PlosOne. (2015). 10 (6):e0128808
Johannes A. Hofberger, Aldana M. Ramirez, Erik van der Bergh, Xinguang Zhu, Harro J. Bouwmeester, Robert C. Schuurink, and M. Eric Schranz
(See online at https://doi.org/10.1371/journal.pone.0128808) - (2016) Proteomics of terpenoid biosynthesis and secretion in trichomes of higher plant species. Biochimica et Biophysica Acta 1864: 1039–1049
Champagne A, Boutry M
(See online at https://doi.org/10.1016/j.bbapap.2016.02.010) - (2016): Plant surface reactions: an opportunistic ozone defence mechanism impacting atmospheric chemistry.In: Atmospheric Chemistry and Physics 16/1, pp. 277 - 292
Jud, W.; Fischer, L.; Canaval, E.; Wohlfahrt, G.; Tissier, A.; Hansel, A.
(See online at https://doi.org/10.5194/acp-16-277-2016) - Engineering of Tomato Glandular Trichomes for the Production of Specialized Metabolites. Methods of Enzymology. (2016). 576:305-331
R.W.J. Kortbeek, J. Xu, A. Ramirez, E. Spyropoulou, P. Diergaarde, I. Otten-Bruggeman, M. de Both, R. Nagel, A. Schmidt, R.C. Schuurink, and P.M. Bleeker
(See online at https://doi.org/10.1016/bs.mie.2016.02.014) - (2017) A comprehensive proteome map of glandular trichomes of hop (Humulus lupulus L.) female cones: Identification of biosynthetic pathways of the major terpenoid-related compounds and possible transport proteins Proteomics 17
Champagne A, Boutry M
(See online at https://doi.org/10.1002/pmic.201600411) - (2017) Plant glandular trichomes: natural cell factories of high biotechnological interest. Plant Physiology175: 6-22
Huchelmann A, Boutry M, Hachez C
(See online at https://doi.org/10.1104/pp.17.00727)
