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Updated: May 18, 2026

Generation of Transgenic Hydra by Embryo Microinjection
Published on: September 11, 2014
What hydra has to say about the role and origin of symbiotic interactions
1Zoologisches Institut der Christian-Albrechts-Universität zu Kiel, Germany. tbosch@zoologie.uni-kiel.de
Abstract:
The Hydra holobiont involves at least three types of organisms that all share a long coevolutionary history and appear to depend on each other. Here I review how symbiotic algae and stably associated bacteria interact with the Hydra host and where in the tissue they are located. In particular I discuss the role of Toll-like receptor (TLR) signaling in maintaining Hydra's species-specific microbiota. I also discuss studies in Hydra viridis and its symbiotic Chlorella algae which indicate that the symbiotic algae are critically involved in the control of sexual differentiation in green Hydra. Finally, I review the state of "omics" in this tripartite association and the fact that the functioning of this holobiont is also a tale of several genomes.
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