TACK Superphylum and Lokiarchaeota Evolution: Dissecting the Ecology and Evolution of Archaea to Elucidate the Prokaryote to Eukaryote Transition

Informations projet

TACKLE

N° de convention de subvention: 695192

DOI

10.3030/695192

Projet clôturé

Date de signature de la CE 28 Juillet 2016

Date de début 1 Août 2016

Date de fin 31 Juillet 2022

Financé au titre de

• EXCELLENT SCIENCE - European Research Council (ERC)

Coût total

€ 2 500 000,00

Contribution de l’UE

€ 2 500 000,00

Coordonné par

UNIVERSITAT WIEN
Austria

Periodic Reporting for period 4 - TACKLE (TACK Superphylum and Lokiarchaeota Evolution: Dissecting the Ecology and Evolution of Archaea to Elucidate the Prokaryote to Eukaryote Transition)

Période du rapport: 2021-02-01 au 2022-07-31

Résumé du contexte et des objectifs généraux du projet

Archaea arose as one of the earliest life forms on Earth probably at about the same time as Bacteria. They have unique cell membranes and many of their cellular machineries are primordial versions of those in complex multicellular life forms (Eukaryotes). This project investigated two lineages of Archaea that can give clues to some of the most fundamental questions in biology: how did organisms expand from hot into moderate and cold environments on the early Earth and what kind of archaeon led to the evolution of Eukaryotes by incorporating a bacterium (which later evolved into mitochondria) into its cell. Without this event, no complex life forms would exist on Earth.
To address these questions it was a major objective of this project to cultivate and study organisms of two crucial lineages: Lokiarchaea of the new phylum Asgardarchaeota that are the closest known living relatives to Eukaryotes and thermophilic Thaumarchaeota from hot springs whose descendants have radiated into moderate environments on Earth.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

Novel habitats of Asgardarchaeota were discovered and well and stably growing enrichments of the lineage Lokiarchaeia were obtained. Their cells revealed an unprecedented cellular and cell wall complexity that shows the evolutionary emergence of actin-based cytoskeleton long before the emergence of Eukaryotes and a unusual and diverse cell wall that might particularly well interact with its biotic and abiotic environment. A thermophilic ammonia oxidizing Thaumarchaeote was obtained in pure culture and together with 38 further Thaumarchaeota genomes was used to reconstruct the evolution and ecological adaptations of this group into moderate environments. This revealed an enormous repertoire of proteins to cope with oxygen stress, apparently to alleviate the elevated amounts of oxygen in environments of decreasing temperature.
Our work was published in 15 peer-reviewed publications and presented on 3 conferences. At least 6 further publications are currently in preparation and more are expected to come.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

The collaboration with a group at ETH Zurich experienced in cryo-EM and other imaging techniques has allowed to get unprecedented insights into features of the cultivated Lokiarchaeote that have never been seen before. Since this enrichment is the first of its kind that reaches high cell densities, it representes a tractable organism for many investigations to come, including metabolic reconstructions, identification of cell wall components, cell division machinery and other components that will shed light on the early evolution of machineries which led to the emergence of eukaryotes.

Sampling on top of the volcano in Vulcano island, Liparic islands

Researchers walking by a volcano crater in Etna, Sicily