Host-microbe cross talk in the early metazoan taxa Porifera and anthozoan Cnidaria

The term “metaorganism” was coined in recognition of the fact that in the environment, all multicellular hosts (animals, plants) associate with microorganisms. The concept has profound impacts on our understanding of ecology which seeks to understand the interactions between organisms and between organisms and their environment. There is a growing awareness that such microbial communities may fulfill many essential functions, from nutrition to development and defense against pathogens.

This proposal B1 seeks to investigate host-microbe interactions in two early-branching metazoans, sponges and cnidarians. It was shown that sponges and cnidarians are colonized by specific bacterial communities, which is suggestive of highly selective pressures by the host animal. Recent genome projects of sponges and cnidarians have identified potential receptors, signal transduction cascades, and effector molecules involved in epithelial defence. In this proposal, we hypothesize that there is an intimate interaction between bacterial community and the host immune system and that the bacterial colonizers will contribute to host fitness. Neither aspect has been investigated in detail in the proposed experimental models. To elucidate these interactions, we will focus on two main aims in Nematostella and two selected sponge species in a comparative approach:
1. Host mechanisms involved in recognition and establishment of specific bacterial colonization.
2. Bacterial function and localization during development.

Together, these insights, which will be derived from in vitro and in vivo studies, will unveil ancient mechanisms controlling host-microbe recognition, function and homeostasis during development. Because these phyla have preserved much of the genetic complexity of the common metazoan ancestor it promises to be highly informative to discover evolutionarily conserved mechanisms controlling host-microbe interactions.


Dr. Anna Roik

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

Martin T. Jahn

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

Laura Baldassarre

PhD Candidate, Associated Junior Researcher
Kiel University Zoological Institute



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