Increased incompatibility of heterologous algal symbionts under thermal stress in the cnidarian-dinoflagellate model Aiptasia

Abstract
Rising ocean temperatures are increasing the rate and intensity of coral mass bleaching events, leading to the collapse of coral reef ecosystems. To better understand the dynamics of coral-algae symbioses, it is critical to decipher the role each partner plays in the holobiont’s thermotolerance. Here, we investigated the role of the symbiont by comparing transcriptional heat stress responses of anemones from two thermally distinct locations, Florida (CC7) and Hawaii (H2) as well as a heterologous host-symbiont combination composed of CC7 host anemones inoculated with the symbiont Breviolum minutum (SSB01) from H2 anemones (CC7-B01). We find that oxidative stress and apoptosis responses are strongly influenced by symbiont type, as further confirmed by caspase-3 activation assays, but that the overall response to heat stress is dictated by the compatibility of both partners. Expression of genes essential to symbiosis revealed a shift from a nitrogen- to a carbon-limited state only in the heterologous combination CC7-B01, suggesting a bioenergetic disruption of symbiosis during stress. Our results indicate that symbiosis is highly fine-tuned towards particular partner combinations and that heterologous host-symbiont combinations are metabolically less compatible under stress. These results are essential for future strategies aiming at increasing coral resilience using heterologous thermotolerant symbionts.

Citation
Cziesielski, M. J., Liew, Y. J., Cui, G., & Aranda, M. (2022). Increased incompatibility of heterologous algal symbionts under thermal stress in the cnidarian-dinoflagellate model Aiptasia. Communications Biology, 5(1). https://doi.org/10.1038/s42003-022-03724-y

Acknowledgements
We thank Craig Michell for RNAseq library preparation, Alicia Schmidt-Roach for anemone husbandry and Jean-Baptiste Raina for feedback on the manuscript. Research reported in this publication was supported by baseline funding from KAUST to M.A.

Publisher
Springer Science and Business Media LLC

Journal
Communications Biology

DOI
10.1038/s42003-022-03724-y

PubMed ID
35902758

Additional Links
https://www.nature.com/articles/s42003-022-03724-y

Relations
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  • [Software]
    Title: lyijin/increased_incompatibility: Code and intermediate files to replicate analysis for a manuscript in review.. Publication Date: 2022-02-09. github: lyijin/increased_incompatibility Handle: 10754/680181

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