B2

Microbiota-host interactions at the base of the metazoan tree

This project addresses in a comparative approach the presence, establishment and functional consequences of microbiota in two basal metazoan animals, the comb jelly Mnemiopsis leidyi (Ctenophora) and the cnidarian Aurelia aurita. Both occur in the same ocean habitat, and share the same food, facilitating an inter-phylum comparison by controlling for environment and bacterial colonizer pool.

The project aims to compare the role of environment, external disturbance and challenge by opportunistic pathogens for the specificity and functioning of associated microbiota. First, we will analyze and evaluate the relative effects of environment versus host genotypes on the establishment and the composition of the respective microbiota. Second, we will evaluate the role of the microbiota for host fitness correlated functions including successful invasion (Mnemiopsis) and life cycle decisions (Aurelia and Mnemiopsis). To this end, animals will be made germ-free, and experimentally controlled recolonization with defined microbial communities compared to controls will allow us to evaluate diverse fitness-correlated effects in the laboratory. A third key objective is to study the ways of inter-kingdom communication in establishing a specific microbiota in both hosts, including host immunity and bacterial communication. In particular, we address mechanisms of signal exchange between host and microbiota, including quorum quenching strategies (interference with bacterial cell-cell communication). Finally, we will assess how associated microbiota is involved in host defense targeting opportunistic pathogens.

The proposed comparative approach will allow insights into general and specific hostmicrobe interactions and (fitness-correlated) functions of the associated microbiota. Depending on the host gene and receptor repertoire we expect different mechanisms and end-points of host-microbe interaction among both phyla. The project will contribute to the CRC by broadening the comparative approach at the base of the metazoan tree, allowing deep evolutionary insight into ancient hostmicrobial interactions.

Researchers

Dr. Olivia Roth

Postdoctoral Researcher, Associated Junior Researcher
GEOMAR - Helmholtz Centre for Ocean Research Kiel

Dr. Simon Güllert

Postdoctoral Researcher, Associated Junior Researcher
Kiel University Institute for General Microbiology

Publications

2017

Microbial contributions to the persistence of coral reefs.

Webster N S, Reusch T B H (2017); ISME J., doi: 10.1038/ismej.2017.66