Chimeric origins of ochrophytes and haptophytes revealed through an ancient plastid proteome

Richard G. Dorrell, Gillian Gile, Giselle McCallum, Raphaël Méheust, Eric P. Bapteste, Christen M. Klinger, Loraine Brillet-Guéguen, Katalina D. Freeman, Daniel J. Richter, Chris Bowler

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39 Scopus citations

Abstract

Plastids are supported by a wide range of proteins encoded within the nucleus and imported from the cytoplasm. These plastid-targeted proteins may originate from the endosymbiont, the host, or other sources entirely. Here, we identify and characterise 770 plastid- targeted proteins that are conserved across the ochrophytes, a major group of algae including diatoms, pelagophytes and kelps, that possess plastids derived from red algae. We show that the ancestral ochrophyte plastid proteome was an evolutionary chimera, with 25% of its phylogenetically tractable nucleus-encoded proteins deriving from green algae. We additionally show that functional mixing of host and plastid proteomes, such as through dual-targeting, is an ancestral feature of plastid evolution. Finally, we detect a clear phylogenetic signal from one ochrophyte subgroup, the lineage containing pelagophytes and dictyochophytes, in plastid- targeted proteins from another major algal lineage, the haptophytes. This may represent a possible serial endosymbiosis event deep in eukaryotic evolutionary history.

Original languageEnglish (US)
Article numbere23717
JournaleLife
Volume6
DOIs
StatePublished - May 12 2017

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Medicine(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Dorrell, R. G., Gile, G., McCallum, G., Méheust, R., Bapteste, E. P., Klinger, C. M., Brillet-Guéguen, L., Freeman, K. D., Richter, D. J., & Bowler, C. (2017). Chimeric origins of ochrophytes and haptophytes revealed through an ancient plastid proteome. eLife, 6, [e23717]. https://doi.org/10.7554/eLife.23717