Research article summary (published 14 Oct 2009):

Plastid genomes of two brown algae, Ectocarpus siliculosus and Fucus vesiculosus: further insights on the evolution of red-algal derived plastids.

Full Abstract

BACKGROUND: Heterokont algae, together with cryptophytes, haptophytes and some alveolates, possess red-algal derived plastids. The chromalveolate hypothesis proposes that the red-algal derived plastids of all four groups have a monophyletic origin resulting from a single secondary endosymbiotic event. However, due to incongruence between nuclear and plastid phylogenies, this controversial hypothesis remains under debate. Large-scale genomic analyses have shown to be a powerful tool for phylogenetic reconstruction but insufficient sequence data have been available for red-algal derived plastid genomes. RESULTS: The chloroplast genomes of two brown algae, Ectocarpus siliculosus and Fucus vesiculosus, have been fully sequenced. These species represent two distinct orders of the Phaeophyceae, which is a major group within the heterokont lineage. The sizes of the circular plastid genomes are 139,954 and 124,986 base pairs, respectively, the size difference being due principally to the presence of longer inverted repeat and intergenic regions in E. siliculosus. Gene contents of the two plastids are similar with 139-148 protein-coding genes, 28-31 tRNA genes, and 3 ribosomal RNA genes. The two genomes also exhibit very similar rearrangements compared to other sequenced plastid genomes. The tRNA-Leu gene of E. siliculosus lacks an intron, in contrast to the F. vesiculosus and other heterokont plastid homologues, suggesting its recent loss in the Ectocarpales. Most of the brown algal plastid genes are shared with other red-algal derived plastid genomes, but a few are absent from raphidophyte or diatom plastid genomes. One of these regions is most similar to an apicomplexan nuclear sequence. The phylogenetic relationship between heterokonts, cryptophytes and haptophytes (collectively referred to as chromists) plastids was investigated using several datasets of concatenated proteins from two cyanobacterial genomes and 18 plastid genomes, including most of the available red algal and chromist plastid genomes. CONCLUSION: The phylogenetic studies using concatenated plastid proteins still do not resolve the question of the monophyly of all chromist plastids. However, these results support both the monophyly of heterokont plastids and that of cryptophyte and haptophyte plastids, in agreement with nuclear phylogenies.

Author information

Author/s: Le Corguillé, Gildas (G); Pearson, Gareth (G); Valente, Marta (M); Viegas, Carla (C); Gschloessl, Bernhard (B); Corre, Erwan (E); Bailly, Xavier (X); Peters, Akira F (AF); Jubin, Claire (C); Vacherie, Benoit (B); Cock, J Mark (JM); Leblanc, Catherine (C);

Affiliation: CNRS, UMR7139, Marine Plants and Biomolecules, Station Biologique, Roscoff, France. lecorguille(-atsign-)sb-roscoff.fr

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: BMC evolutionary biology (BMC Evol Biol), published in England. (Language: eng)

Reference: 2009-; vol 9 (issue ) : pp 253

Dates: Created 2009/10/23; Completed 2009/11/13;

PMID: 19835607, status: MEDLINE (last retrieved date: 11/15/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MeSH Headings (categories) shown below.

Algae, Brown - genetics Base Sequence Chromosome Mapping DNA, Algal - genetics Evolution, Molecular Fucus - genetics

Fucus - genetics Genome, Chloroplast - genetics Molecular Sequence Data Phylogeny Plastids - genetics Sequence Analysis, DNA

Note: Bold headings indicate primary MeSH headings or qualifiers.

Associated Chemicals: DNA, Algal (0)

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