Erschienen in:Proceedings of the National Academy of Sciences of the United States of America
Sprache:
Englisch
ISSN:
0027-8424;
1091-6490
Entstehung:
Anmerkungen:
Beschreibung:
<p>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 <italic>TPS</italic> 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 <italic>Dictyostelium discoideum</italic> was selected for functional study of the identified TPSs. <italic>D. discoideum</italic> 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 <italic>D. discoideum TPS</italic> genes was induced during development. Upon heterologous expression, all nine TPSs from <italic>D. discoideum</italic> showed sesquiterpene synthase activities. Some also exhibited monoterpene and/or diterpene synthase activities. Direct measurement of volatile terpenes in cultures of <italic>D. discoideum</italic> revealed essentially no emission at an early stage of development. In contrast, a bouquet of terpenes, dominated by sesquiterpenes including β-barbatene and (<italic>E,E</italic>)-α-farnesene, was detected at the middle and late stages of development, suggesting a development-specific function of volatile terpenes in <italic>D. discoideum.</italic> The patchy distribution of <italic>TPS</italic> genes in the eukaryotic domain and the evidence for <italic>TPS</italic> function in <italic>D. discoideum</italic> indicate that the <italic>TPS</italic> genes mediate lineage-specific adaptations.</p>