Abstract
Many multicellular organisms rely on symbiotic associations for support of metabolic activity, protection, or energy. Understanding the mechanisms involved in controlling such interactions remains a major challenge. In an unbiased approach we identified key players that control the symbiosis between Hydra viridissima and its photosynthetic symbiont Chlorella sp. A99. We discovered significant up-regulation of Hydra genes encoding a phosphate transporter and glutamine synthetase suggesting regulated nutrition supply between host and symbionts. Interestingly, supplementing the medium with glutamine temporarily supports in vitro growth of the otherwise obligate symbiotic Chlorella, indicating loss of autonomy and dependence on the host. Genome sequencing of Chlorella sp. A99 revealed a large number of amino acid transporters and a degenerated nitrate assimilation pathway, presumably as consequence of the adaptation to the host environment. Our observations portray ancient symbiotic interactions as a codependent partnership in which exchange of nutrients appears to be the primary driving force.
Article and author information
Author details
Funding
Japan Society for the Promotion of Science (Young Scientists (B) 25840132)
- Mayuko Hamada
Japan Society for the Promotion of Science (Scientific Research (C) 15K07173)
- Mayuko Hamada
Deutsche Forschungsgemeinschaft (CRC1182)
- Thomas C G Bosch
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Paul G Falkowski, Rutgers University, United States
Publication history
- Received: January 16, 2018
- Accepted: May 26, 2018
- Accepted Manuscript published: May 31, 2018 (version 1)
- Version of Record published: June 26, 2018 (version 2)
Copyright
© 2018, Hamada et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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