Transcriptomic evidence that longevity of acquired plastids in the photosynthetic slugs Elysia timida and Plakobrachus ocellatus does not entail lateral transfer of algal nuclear genes

  • Sacoglossan sea slugs are unique in the animal kingdom in that they sequester and maintain active plastids that they acquire from the siphonaceous algae upon which they feed, making the animals photosynthetic. While most sacoglossan species digest their freshly ingested plastids within hours, four species from the family Plakobranchidae retain their stolen plastids (kleptoplasts) in a photosynthetically active state on time scales of weeks to months. The molecular basis of plastid maintenance within the cytosol of digestive gland cells in these photosynthetic metazoans is yet unknown, but is widely thought to involve gene transfer from the algal food source to the slugs based upon previous investigations of single genes. Indeed, normal plastid development requires hundreds of nuclear-encoded proteins, with protein turnover in photosystem II in particular known to be rapid under various conditions. Moreover, only algal plastids, not the algal nuclei, are sequestered by the animals during feeding. If algal nuclear genes are transferred to the animal either during feeding or in the germ line, and if they are expressed, then they should be readily detectable with deep-sequencing methods. We have sequenced expressed mRNAs from actively photosynthesizing, starved individuals of two photosynthetic sea slug species, Plakobranchus ocellatus Van Hasselt, 1824 and Elysia timida Risso, 1818. We find that nuclear-encoded, algal-derived genes specific to photosynthetic function are expressed neither in P. ocellatus nor in E. timida. Despite their dramatic plastid longevity, these photosynthetic sacoglossan slugs do not express genes acquired from algal nuclei in order to maintain plastid function.

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Author:Heike WägeleORCiDGND, Oliver DeuschORCiD, Katharina HändelerGND, Rainer Martin, Valerie SchmittGND, Gregor ChristaORCiDGND, Britta Pinzger, Sven B. GouldORCiDGND, Tal DaganORCiDGND, Annette Klussmann-KolbGND, William Martin
Parent Title (German):Molecular biology and evolution
Document Type:Article
Date of Publication (online):2010/09/24
Year of first Publication:2010
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2010/09/24
First Page:699
Last Page:706
©The Author(s) 2010. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Source:In: Molecular biology and evolution , doi:10.1093/molbev/msq239 ,
Institutes:Biowissenschaften / Institut für Ökologie, Evolution und Diversität
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlung Biologie / Sondersammelgebiets-Volltexte
Licence (German):License LogoDeutsches Urheberrecht