Biology and evolution of the intracellular lifestyle in protists

Current projects

Bacteria infecting protists are diverse and often share conserved virulence mechanisms. Yet, they may differ fundamentally with respect to their intracellular niche and strategies for host-interaction. These symbionts often share a common ancestry with bacterial pathogens of humans, suggesting an environmental origin of the intracellular lifestyle in eukaryotes.

Aim: This project will characterize common themes and differences of microbe-host interaction among known bacterial symbionts in protists. Molecular mechanisms of host-interaction will be investigated for novel, yet uncharacterized symbionts.

Approach: Comprehensive genomics and phylogenomics analyses will provide the basis for an evolutionary framework of known bacteria-protist associations. Novel cultivation and screening approaches will be used to obtain novel protist isolates and their symbionts. Symbiont-host interactions will be characterized by a systems biology approach including transcriptomics, proteomics, and metabolomics.

Relevance: Understanding the diversity of microbe-host interactions in single-cell eukaryotes provides an important framework for understanding how microbe-host interactions evolved and function in multicellular eukaryotes, including humans.

Student: Artur Zaduryan

Faculty: Horn (PI), Rattei, Petersen, Wagner

Funding: FWF project MAINTAIN

Selected Publications:

König L, Wentrup C, Schulz F, Wascher F, Swanson MS, Buchrieser C, Horn M (2019). Symbiont-mediated defense against Legionella pneumophila in amoebae. mBio 10(3): e00333-19. doi: 10.1128/mBio.00333-19.

Collingro A, Köstlbacher S, Mussmann M, Stepanauskas R, Hallam SJ, Horn M (2017). Unexpected genomic features in widespread intracellular bacteria: evidence for motility of marine chlamydiae. ISME J 10: 2334-2344. doi: 10.1038/ismej.2017.95.

Böck D, Medeiros JM, Tsao HF, Penz T, Weiss GL, Aistleitner K, Horn M, Pilhofer M. (2017). In situ architecture, function, and evolution of a contractile injection system. Science 6352: 713-717. doi: 10.1126/science.aan7904.

Domman D, Horn M, Embley TM, Williams TA (2015). Plastid establishment did not require a chlamydial partner. Nature Commun 6: 6421. doi: 10.1038/ncomms7421.