Article

Plant cholesterol biosynthetic pathway overlaps with phytosterol metabolism

  • Nature Plants 3, Article number: 16205 (2016)
  • doi:10.1038/nplants.2016.205
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Abstract

The amount of cholesterol made by many plants is not negligible. Whereas cholesterogenesis in animals was elucidated decades ago, the plant pathway has remained enigmatic. Among other roles, cholesterol is a key precursor for thousands of bioactive plant metabolites, including the well-known Solanum steroidal glycoalkaloids. Integrating tomato transcript and protein co-expression data revealed candidate genes putatively associated with cholesterol biosynthesis. A combination of functional assays including gene silencing, examination of recombinant enzyme activity and yeast mutant complementation suggests the cholesterol pathway comprises 12 enzymes acting in 10 steps. It appears that half of the cholesterogenesis-specific enzymes evolved through gene duplication and divergence from phytosterol biosynthetic enzymes, whereas others act reciprocally in both cholesterol and phytosterol metabolism. Our findings provide a unique example of nature's capacity to exploit existing protein folds and catalytic machineries from primary metabolism to assemble a new, multi-step metabolic pathway. Finally, the engineering of a ‘high-cholesterol’ model plant underscores the future value of our gene toolbox to produce high-value steroidal compounds via synthetic biology.

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Acknowledgements

We are grateful to D. Twafik for useful suggestions in phylogenetic analysis. A.A. is the incumbent of the Peter J. Cohn Professorial Chair. We thank the Adelis Foundation, the Leona M. and Harry B. Helmsley Charitable Trust, the Jeanne and Joseph Nissim Foundation for Life Sciences, Tom and Sondra Rykoff Family Foundation Research and the Raymond Burton Plant Genome Research Fund for supporting the laboratory activity of A.A. The work was supported by the Israel Science Foundation (ISF Grant No. 1805/15) and the European Research Council (ERC; SAMIT-FP7) personal grants to A.A. P.D.S. is grateful to the Planning and Budgeting Committee of the Council for Higher Education, Israel for the VATAT fellowship. The research in the laboratory of A.G. was financially supported by the VIB International PhD Fellowship Program (fellowship to P.A.) and the Research Foundation Flanders (postdoctoral fellowships to J.P. and L.P.). A.K was supported by a short-term EMBO fellowship (EMBO-ASTF-146-2014). The research in the laboratories of A.A. and A.G. was supported by the European Union Seventh Framework Program FP7/2007–2013 under grant agreement no. 613692–TriForC.

Author information

Affiliations

  1. Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel

    • Prashant D. Sonawane
    • , Sayantan Panda
    • , Jedrzej Szymanski
    • , Hassan Massalha
    • , Sergey Malitsky
    • , Efrat Almekias-Siegl
    • , Ilana Rogachev
    • , Sagit Meir
    • , Pablo D. Cárdenas
    • , Athar Masri
    •  & Asaph Aharoni
  2. Department of Plant Systems Biology, VIB, B-9052 Gent, Belgium

    • Jacob Pollier
    • , Philipp Arendt
    • , Laurens Pauwels
    •  & Alain Goossens
  3. Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium

    • Jacob Pollier
    • , Philipp Arendt
    • , Laurens Pauwels
    •  & Alain Goossens
  4. Department of Botany, Savitribai Phule Pune University, Ganeshkhind, Pune 411007, India

    • Sayantan Panda
    •  & Avinash Kamble
  5. School of Computer Sciences and Sackler School of Medicine, Tel Aviv University, Tel-Aviv 69978, Israel

    • Jedrzej Szymanski
  6. Israel Structural Proteomics Centre, Weizmann Institute of Science, Rehovot 7610001, Israel

    • Meital Yona
    •  & Tamar Unger
  7. Department of Biochemistry and Microbiology, Ghent University, B-9000 Gent, Belgium

    • Philipp Arendt
  8. VIB Medical Biotechnology Center, B-9000 Gent, Belgium

    • Philipp Arendt
  9. Department of Vegetable Research, ARO-Volcani Center, Bet Dagan 50250, Israel

    • Marina Petrikov
    •  & Arthur A. Schaffer
  10. Institut de Biologie Moléculaire des Plantes du CNRS & Université de Strasbourg, Institut de Botanique, Strasbourg, France

    • Hubert Schaller
  11. Plant Molecular Biology Unit, Division of Biochemical Sciences, Council of Scientific and Industrial Research–National Chemical Laboratory, Pune 411008, Maharashtra, India

    • Ashok P. Giri

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Contributions

P.D.S. designed experiments, performed the research and wrote the paper. J.P., P.A., L.P. and A.G. designed part of the experiments and performed all yeast complementation assays and wrote the paper. S.P. assisted in the VIGS experiments. J.S. and E.S. assisted in the co-expression data analysis. H.M. performed the confocal imaging experiments for localization studies. I.R. and S. Meir assisted with metabolomics data analysis and operated the LCMS. S. Malitsky assisted with GC-S metabolomics data analysis and operated the GCMS. M.Y. and T.U. performed recombinant protein expression in insect cells and isolated microsomes fractions. P.D.C. assisted in wild tomato accessions RNA sequencing. A.M. assisted in sterol extractions and tissue culture work. A.K. and A.P.G. designed part of the research and wrote the paper. H.S. assisted in data analysis and manuscript preparation. A.A. designed the research and wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Asaph Aharoni.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information.

  2. 2.

    Supplementary Data 2

    Amino acid sequences.

Excel files

  1. 1.

    Supplementary Data 1

    Detailed list of genes.