Updating algal evolutionary relationships through plastid genome sequencing: did alveolate plastids emerge through endosymbiosis of an ochrophyte?

0451323 - BC 2016 RIV GB eng J - Journal Article
Ševčíková, T. - Horák, Aleš - Klimeš, V. - Zbránková, V. - Demir-Hilton, E. - Sudek, S. - Jenkis, J. - Schmutz, J. - Přibyl, Pavel - Fousek, Jan - Vlček, Čestmír - Lang, B.F. - Oborník, Miroslav - Worden, A.Z. - Eliáš, M.
Updating algal evolutionary relationships through plastid genome sequencing: did alveolate plastids emerge through endosymbiosis of an ochrophyte?
Scientific Reports. Roč. 5, MAY 28 2015 (2015), s. 10134. ISSN 2045-2322. E-ISSN 2045-2322
R&D Projects: GA ČR(CZ) GA13-33039S; GA ČR GPP506/12/P931
Grant - others:GA MŠk(CZ) LO1208; GA MŠk(CZ) ED2.1.00/03.0100
Institutional support: RVO:60077344 ; RVO:67985939 ; RVO:68378050
Keywords : phylogenetic position * Chromera velia * Dinoflagellate
Subject RIV: EG - Zoology; EF - Botanics (UMG-J); EF - Botanics (BU-J)
Impact factor: 5.228, year: 2015

Algae with secondary plastids of a red algal origin, such as ochrophytes (photosynthetic stramenopiles), are diverse and ecologically important, yet their evolutionary history remains controversial. We sequenced plastid genomes of two ochrophytes, Ochromonas sp. CCMP1393 (Chrysophyceae) and Trachydiscus minutus (Eustigmatophyceae). A shared split of the clpC gene as well as phylogenomic analyses of concatenated protein sequences demonstrated that chrysophytes and eustigmatophytes form a clade, the Limnista, exhibiting an unexpectedly elevated rate of plastid gene evolution. Our analyses also indicate that the root of the ochrophyte phylogeny falls between the recently redefined Khakista and Phaeista assemblages. Taking advantage of the expanded sampling of plastid genome sequences, we revisited the phylogenetic position of the plastid of Vitrella brassicaformis, a member of Alveolata with the least derived plastid genome known for the whole group. The results varied depending on the dataset and phylogenetic method employed, but suggested that the Vitrella plastids emerged from a deep ochrophyte lineage rather than being derived vertically from a hypothetical plastid-bearing common ancestor of alveolates and stramenopiles. Thus, we hypothesize that the plastid in Vitrella, and potentially in other alveolates, may have been acquired by an endosymbiosis of an early ochrophyte.
Permanent Link: http://hdl.handle.net/11104/0252506