The role of membrane vesicles for archaeal virus-host interactions

• Applicant: Professorin Dr. Susanne Erdmann
• Subject Area: Virology ; Microbial Ecology and Applied Microbiology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 465087098

Prokaryotic membrane vesicles (MVs), also described as extracellular vesicles (EVs) in the literature, are nano-sized (10-300nm) spherical structures, derived from the cell surface. By current understanding they are associated with various crucial functions mostly related to the communication of cells with their environment. Most importantly, they have also been shown to play significant roles for virus-host interactions. Recent studies revealed that bacterial MVs can both reduce infectivity of a virus, by virus adsorption to MVs instead of host cells, and increase infectivity of a virus, by spreading virus receptors from sensitive to resistant host cells. Almost nothing is known about the existence and the physiological role of MVs in the third domain of life, Archaea, in contrast to Bacteria, subject of most current studies on MVs. Archaea comprise globally abundant and diverse microorganisms, play a critical role for global environmental health and are phylogenetically closely related to Eukaryota. MVs of hyperthermophilic Archaea and specialized MVs (plasmid vesicles (PVs)) of halophilic Archaea (Haloarchaea) were shown to transfer plasmid DNA between cells, indicating that archaeal MVs can be important gene transferring agents. Additionally, we discovered recently that MVs produced by several haloarchaeal species are highly enriched in particular small RNAs (unpublished). This is the first time that small RNAs are found in archaeal MVs and we hypothesise, that these small RNAs are involved in cell-cell communication and could have an influence on virus-host interactions. The role of MVs for virus-host interactions has not yet been investigated for archaea. This project will focus on both, the influence of viruses on MV (and PV) production in halophilic archaea (haloarchaea) and the role of MVs (and PVs) produced by haloarchaea in virus-host interactions. We will test the MV production, MV morphology and MV composition (including RNA content) of different haloarchaeal strains under the influence of different viruses and other environmental stress factors. This will significantly increase our knowledge about haloarchaeal MV formation and in particular the influence of viruses on MV formation. Most importantly, we will test the direct influence (physical contact) and the indirect influence (cell-cell communication and transfer of viral information by MVs) of MVs isolated from virus resistant and virus susceptible strains on the infectivity of different types of viruses. Thereby, we expect to elucidate whether and to which extent MVs play a role for archaeal virus-host interactions and significantly enhance our understanding of virus-host interactions in prokaryotes.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2330: New concepts in prokaryotic virus-host interactions - from single cells to microbial communities
• Co-Investigator: Dr. Coraline Mercier