Metabolic co-dependence drives the evolutionarily ancient Hydra-Chlorella symbiosis
- Okinawa Institute of Science and Technology Graduate University (OIST), Japan
- Kiel University, Germany
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.
Data availability
Microarray information and the data series are accessible at NCBI GEO under accession number GPL23280 and GSE97633 respectively. All the results of microarray analysis are included in Supplementary Table 1.The Whole Genome Shotgun project of Chlorella sp. A99 has been deposited at DDBJ/ENA/GenBank under the accession PCFQ00000000 (BioProject ID: PRJNA412448). Genome sequences and gene models are also accessible at the website of OIST Marine Genomics Unit Genome Project (http://marinegenomics.oist.jp/chlorellaA99/viewer/info?project_id=65).All data generated by qPCR are included in Source Data: Figure2, Figure2 - Figure supplement 1, Source Data: Figure3, Source Data: Figure3 - Figure Supplement 2 and Source Data: Table 2, Table 4
Article and author information
Author details
Konstantin Khalturin
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
Version 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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Metabolic co-dependence drives the evolutionarily ancient Hydra-Chlorella symbiosis
eLife 7:e35122.
https://doi.org/10.7554/eLife.35122
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