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Proc Natl Acad Sci U S A. 2016 Oct 25;113(43):12132-12137. Epub 2016 Oct 7.

Terpene synthase genes in eukaryotes beyond plants and fungi: Occurrence in social amoebae.

Author information

1
Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996.
2
Department of Biochemistry, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany.
3
Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996.
4
Graduate Program in Structural Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, TX 77030; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030.
5
Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, 53121 Bonn, Germany.
6
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030.
7
Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996; Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996; fengc@utk.edu.

Abstract

Terpenes are structurally diverse natural products involved in many ecological interactions. The pivotal enzymes for terpene biosynthesis, terpene synthases (TPSs), had been described only in plants and fungi in the eukaryotic domain. In this report, we systematically analyzed the genome sequences of a broad range of nonplant/nonfungus eukaryotes and identified putative TPS genes in six species of amoebae, five of which are multicellular social amoebae from the order of Dictyosteliida. A phylogenetic analysis revealed that amoebal TPSs are evolutionarily more closely related to fungal TPSs than to bacterial TPSs. The social amoeba Dictyostelium discoideum was selected for functional study of the identified TPSs. D. discoideum grows as a unicellular organism when food is abundant and switches from vegetative growth to multicellular development upon starvation. We found that expression of most D. discoideum TPS genes was induced during development. Upon heterologous expression, all nine TPSs from D. discoideum showed sesquiterpene synthase activities. Some also exhibited monoterpene and/or diterpene synthase activities. Direct measurement of volatile terpenes in cultures of D. discoideum revealed essentially no emission at an early stage of development. In contrast, a bouquet of terpenes, dominated by sesquiterpenes including β-barbatene and (E,E)-α-farnesene, was detected at the middle and late stages of development, suggesting a development-specific function of volatile terpenes in D. discoideum. The patchy distribution of TPS genes in the eukaryotic domain and the evidence for TPS function in D. discoideum indicate that the TPS genes mediate lineage-specific adaptations.

KEYWORDS:

amoebae; chemical ecology; evolution; terpene synthases; volatiles

PMID:
27790999
PMCID:
PMC5087028
DOI:
10.1073/pnas.1610379113
[Indexed for MEDLINE]
Free PMC Article

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