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Pütter KM, van Deenen N, Müller B, Fuchs L, Vorwerk K, Unland K, Bröker JN, Scherer E, Huber C, Eisenreich W, Prüfer D, Schulze Gronover C. The enzymes OSC1 and CYP716A263 produce a high variety of triterpenoids in the latex of Taraxacum koksaghyz. Sci Rep 2019; 9:5942. [PMID: 30976052 PMCID: PMC6459903 DOI: 10.1038/s41598-019-42381-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 03/28/2019] [Indexed: 01/01/2023] Open
Abstract
Only very little is known about the resin composition of natural rubber from the dandelion species Taraxacum koksaghyz, thus its full characterization could provide new insights into how the isoprenoid end-products influence the physical properties of natural rubber, and this resin might be a good source of highly diverse triterpenoids. Here, we present a comprehensive analysis of the triterpenoid composition in an acetone extract and identified 13 triterpenes and triterpenoids also including the so far unknown pentacyclic compounds lup-19(21)-en-3-ol (1) and its ketone lup-19(21)-en-3-one (2). We purified single triterpenes from the acetone extract by developing a two-step HPLC system that is adapted to the structural differences of the described triterpenoids. Furthermore, we isolated six different oxidosqualene cyclases (OSCs) and two P450 enzymes, and we functionally characterized TkOSC1 and CYP716A263 in Nicotiana benthamiana and Saccharomyces cerevisiae in detail. TkOSC1 is a multifunctional OSC that was capable of synthesizing at least four of the latex-predominant pentacyclic triterpenes (taraxasterol, α-, β-amyrin and lup-19(21)-en-3-ol) while CYP716A263 oxidized pentacyclic triterpenes at the C-3 position. The identified enzymes responsible for biosynthesis and modification of pentacyclic triterpenes in T. koksaghyz latex may represent excellent tools for bioengineering approaches to produce pentacyclic triterpenes heterologously.
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Affiliation(s)
- Katharina M Pütter
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
| | - Nicole van Deenen
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
| | - Boje Müller
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143, Muenster, Germany
| | - Lea Fuchs
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
| | - Kirsten Vorwerk
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
| | - Kristina Unland
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143, Muenster, Germany
| | - Jan Niklas Bröker
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
| | - Emely Scherer
- Technische Universität München, Chair of Biochemistry, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Claudia Huber
- Technische Universität München, Chair of Biochemistry, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Wolfgang Eisenreich
- Technische Universität München, Chair of Biochemistry, Lichtenbergstraße 4, 85747, Garching, Germany
| | - Dirk Prüfer
- University of Muenster, Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143, Muenster, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143, Muenster, Germany
| | - Christian Schulze Gronover
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Schlossplatz 8, 48143, Muenster, Germany.
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Unland K, Pütter KM, Vorwerk K, van Deenen N, Twyman RM, Prüfer D, Schulze Gronover C. Functional characterization of squalene synthase and squalene epoxidase in Taraxacum koksaghyz. Plant Direct 2018; 2:e00063. [PMID: 31245726 PMCID: PMC6508512 DOI: 10.1002/pld3.63] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/12/2018] [Accepted: 05/15/2018] [Indexed: 05/05/2023]
Abstract
The Russian dandelion Taraxacum koksaghyz produces high-value isoprenoids such as pentacyclic triterpenes and natural rubber in the latex of specialized cells known as laticifers. Squalene synthase (SQS) and squalene epoxidase (SQE) catalyze key steps in the biosynthesis of cyclic terpenoids, but neither enzyme has yet been characterized in T. koksaghyz. Genomic analysis revealed the presence of two genes (TkSQS1 and TkSQS2) encoding isoforms of SQS, and four genes (TkSQE1-4) encoding isoforms of SQE. Spatial expression analysis in different T. koksaghyz tissues confirmed that TkSQS1 and TkSQE1 are the latex-predominant isoforms, with highly similar mRNA expression profiles. The TkSQS1 and TkSQE1 proteins colocalized in the endoplasmic reticulum membrane and their enzymatic functions were confirmed by in vitro activity assays and yeast complementation studies, respectively. The functions of TkSQS1 and TkSQE1 were further characterized in the latex of T. koksaghyz plants with depleted TkSQS1 or TkSQE1 mRNA levels, produced by RNA interference. Comprehensive expression analysis revealed the coregulation of TkSQS1 and TkSQE1, along with a downstream gene in the triterpene biosynthesis pathway encoding the oxidosqualene cyclase TkOSC1. This indicates that the coregulation of TkSQS1, TkSQE1, and TkOSC1 could be used to optimize the flux toward specific terpenoids during development.
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Affiliation(s)
- Kristina Unland
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME)MuensterGermany
| | - Katharina M. Pütter
- Institute of Plant Biology and BiotechnologyUniversity of MuensterMuensterGermany
| | - Kirsten Vorwerk
- Institute of Plant Biology and BiotechnologyUniversity of MuensterMuensterGermany
| | - Nicole van Deenen
- Institute of Plant Biology and BiotechnologyUniversity of MuensterMuensterGermany
| | | | - Dirk Prüfer
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME)MuensterGermany
- Institute of Plant Biology and BiotechnologyUniversity of MuensterMuensterGermany
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Pütter KM, van Deenen N, Unland K, Prüfer D, Schulze Gronover C. Isoprenoid biosynthesis in dandelion latex is enhanced by the overexpression of three key enzymes involved in the mevalonate pathway. BMC Plant Biol 2017; 17:88. [PMID: 28532507 PMCID: PMC5441070 DOI: 10.1186/s12870-017-1036-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 05/10/2017] [Indexed: 05/21/2023]
Abstract
BACKGROUND Latex from the dandelion species Taraxacum brevicorniculatum contains many high-value isoprenoid end products, e.g. triterpenes and polyisoprenes such as natural rubber. The isopentenyl pyrophosphate units required as precursors for these isoprenoids are provided by the mevalonate (MVA) pathway. The key enzyme in this pathway is 3-hydroxy-methyl-glutaryl-CoA reductase (HMGR) and its activity has been thoroughly characterized in many plant species including dandelion. However, two enzymes acting upstream of HMGR have not been characterized in dandelion latex: ATP citrate lyase (ACL), which provides the acetyl-CoA utilized in the MVA pathway, and acetoacetyl-CoA thiolase (AACT), which catalyzes the first step in the pathway to produce acetoacetyl-CoA. Here we isolated ACL and AACT genes from T. brevicorniculatum latex and characterized their expression profiles. We also overexpressed the well-characterized HMGR, ACL and AACT genes from Arabidopsis thaliana in T. brevicorniculatum to determine their impact on isoprenoid end products in the latex. RESULTS The spatial and temporal expression profiles of T. brevicorniculatum ACL and AACT revealed their pivotal role in the synthesis of precursors necessary for isoprenoid biosynthesis in latex. The overexpression of A. thaliana ACL and AACT and HMGR in T. brevicorniculatum latex resulted in the accumulation of all three enzymes, increased the corresponding enzymatic activities and ultimately increased sterol levels by ~5-fold and pentacyclic triterpene and cis-1,4-isoprene levels by ~2-fold. Remarkably high levels of the triterpene precursor squalene were also detected in the triple-transgenic lines (up to 32 mg/g root dry weight) leading to the formation of numerous lipid droplets which were observed in root cross-sections. CONCLUSIONS We could show the effective expression of up to three transgenes in T. brevicorniculatum latex which led to increased enzymatic activity and resulted in high level squalene accumulation in the dandelion roots up to an industrially relevant amount. Our data provide insight into the regulation of the MVA pathway in dandelion latex and can be used as a basis for metabolic engineering to enhance the production of isoprenoid end products in this specialized tissue.
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Affiliation(s)
- Katharina M. Pütter
- Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Muenster, Germany
| | - Nicole van Deenen
- Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Muenster, Germany
| | - Kristina Unland
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Muenster, Germany
| | - Dirk Prüfer
- Institute of Plant Biology and Biotechnology, Schlossplatz 8, 48143 Muenster, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Muenster, Germany
| | - Christian Schulze Gronover
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Schlossplatz 8, 48143 Muenster, Germany
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