1. Cell Biology
  2. Plant Biology
Download icon

Photosynthetic sea slugs induce protective changes to the light reactions of the chloroplasts they steal from algae

  1. Vesa Havurinne
  2. Esa Tyystjärvi  Is a corresponding author
  1. University of Turku, Finland
Research Article
  • Cited 2
  • Views 4,922
  • Annotations
Cite this article as: eLife 2020;9:e57389 doi: 10.7554/eLife.57389


Sacoglossan sea slugs are able to maintain functional chloroplasts inside their own cells, and mechanisms that allow preservation of the chloroplasts are unknown. We found that the slug Elysia timida induces changes to the photosynthetic light reactions of the chloroplasts it steals from the alga Acetabularia acetabulum. Working with a large continuous laboratory culture of both the slugs (>500 individuals) and their prey algae, we show that the plastoquinone pool of slug chloroplasts remains oxidized, which can suppress reactive oxygen species formation. Slug chloroplasts also rapidly build up a strong proton motive force upon a dark-to-light transition, which helps them to rapidly switch on photoprotective non-photochemical quenching of excitation energy. Finally, our results suggest that chloroplasts inside E. timida rely on oxygen-dependent electron sinks during rapid changes in light intensity. These photoprotective mechanisms are expected to contribute to the long-term functionality of the chloroplasts inside the slugs.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 2, 3, 4, Figure 4-figure supplement 1 and Figures 5, 6, 7B-E and 8.

Article and author information

Author details

  1. Vesa Havurinne

    Biochemistry, University of Turku, Turku, Finland
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5213-0905
  2. Esa Tyystjärvi

    Biochemistry, University of Turku, Turku, Finland
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6808-7470


Academy of Finland (307335)

  • Esa Tyystjärvi

Suomen Kulttuurirahasto (Graduate student grant)

  • Vesa Havurinne

Suomalainen Tiedeakatemia (Graduate student grant)

  • Vesa Havurinne

University of Turku graduate school, DPMLS (Graduate student grant)

  • Vesa Havurinne

Academy of Finland (333421)

  • Esa Tyystjärvi

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.


Animal experimentation: This study was performed in accordance with EU legislation and directives concerning scientific research on non-cephalopod invertebrates.

Reviewing Editor

  1. Christian S Hardtke, University of Lausanne, Switzerland

Publication history

  1. Received: March 30, 2020
  2. Accepted: October 7, 2020
  3. Accepted Manuscript published: October 20, 2020 (version 1)
  4. Version of Record published: November 20, 2020 (version 2)


© 2020, Havurinne & Tyystjärvi

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.


  • 4,922
    Page views
  • 382
  • 2

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

  1. Further reading

Further reading

  1. Sea slugs steal from algae to harvest energy from sunlight

    1. Cell Biology
    Jennifer M Kunselman et al.
    Research Article Updated

    Many signal transduction systems have an apparent redundancy built into them, where multiple physiological agonists activate the same receptors. Whether this is true redundancy, or whether this provides an as-yet unrecognized specificity in downstream signaling, is not well understood. We address this question using the kappa opioid receptor (KOR), a physiologically relevant G protein-coupled receptor (GPCR) that is activated by multiple members of the Dynorphin family of opioid peptides. We show that two related peptides, Dynorphin A and Dynorphin B, bind and activate KOR to similar extents in mammalian neuroendocrine cells and rat striatal neurons, but localize KOR to distinct intracellular compartments and drive different post-endocytic fates of the receptor. Strikingly, localization of KOR to the degradative pathway by Dynorphin A induces sustained KOR signaling from these compartments. Our results suggest that seemingly redundant endogenous peptides can fine-tune signaling by regulating the spatiotemporal profile of KOR signaling.