Ancestral chloroplast genome in Mesostigma viride reveals an early branch of green plant evolution

Lemieux, Claude; Otis, Christian; Turmel, Monique

doi:10.1038/35001059

Cited by 245 publications

(202 citation statements)

References 20 publications

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“…LD always found T1, except when constant sites were down-weighted by 90% and 100%, where it found T8. The prasinophyte Mesostigma branched basal to land plants but above Chlorella and Nephroselmis in all analyses, in contrast to the position inferred previously by using 53 genes and fewer outgroups (32), but compatible with other recent findings (56). T1-T8 all indicate independent secondary symbioses (plastid origins from eukaryotic symbionts; refs.…”

Section: Resultscontrasting

confidence: 56%

Evolutionary analysis ofArabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus

Martin

Rujan²,

Richly

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

1,068

796

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Chloroplasts were once free-living cyanobacteria that became endosymbionts, but the genomes of contemporary plastids encode only Ϸ5-10% as many genes as those of their free-living cousins, indicating that many genes were either lost from plastids or transferred to the nucleus during the course of plant evolution. Previous estimates have suggested that between 800 and perhaps as many as 2,000 genes in the Arabidopsis genome might come from cyanobacteria, but genome-wide phylogenetic surveys that could provide direct estimates of this number are lacking. We compared 24,990 proteins encoded in the Arabidopsis genome to the proteins from three cyanobacterial genomes, 16 other prokaryotic reference genomes, and yeast. Of 9,368 Arabidopsis proteins sufficiently conserved for primary sequence comparison, 866 detected homologues only among cyanobacteria and 834 other branched with cyanobacterial homologues in phylogenetic trees. Extrapolating from these conserved proteins to the whole genome, the data suggest that Ϸ4,500 of Arabidopsis protein-coding genes (Ϸ18% of the total) were acquired from the cyanobacterial ancestor of plastids. These proteins encompass all functional classes, and the majority of them are targeted to cell compartments other than the chloroplast. Analysis of 15 sequenced chloroplast genomes revealed 117 nuclear-encoded proteins that are also still present in at least one chloroplast genome. A phylogeny of chloroplast genomes inferred from 41 proteins and 8,303 amino acids sites indicates that at least two independent secondary endosymbiotic events have occurred involving red algae and that amino acid composition bias in chloroplast proteins strongly affects plastid genome phylogeny.

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Section: Resultscontrasting

confidence: 56%

Evolutionary analysis ofArabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus

Martin

Rujan²,

Richly

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

1,068

796

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“…It is conceivable that mitochondria and chloroplasts contain export and import systems for biotin, respectively. It was interesting to note in this context that the chloroplast genome of Mesostigma viride, a member of the earliest lineage of green plants (17), encodes a BioY homolog (YCX1-MESVI).…”

Section: Discussionmentioning

confidence: 99%

Biotin uptake in prokaryotes by solute transporters with an optional ATP-binding cassette-containing module

Hebbeln

Rodionov

Alfandega

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

132

190

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BioMNY proteins are considered to constitute tripartite biotin transporters in prokaryotes. Recent comparative genomic and experimental analyses pointed to the similarity of BioMN to homologous modules of prokaryotic transporters mediating uptake of metals, amino acids, and vitamins. These systems resemble ATP-binding cassette-containing transporters and include typical ATPases (e.g., BioM). Absence of extracytoplasmic solute-binding proteins among the members of this group, however, is a distinctive feature. Genome context analyses uncovered that only onethird of the widespread bioY genes are linked to bioMN. Many bioY genes are located at loci encoding biotin biosynthesis, and others are unlinked to biotin metabolic or transport genes. Heterologous expression of the bioMNY operon and of the single bioY of the ␣-proteobacterium Rhodobacter capsulatus conferred biotin-transport activity on recombinant Escherichia coli cells. Kinetic analyses identified BioY as a high-capacity transporter that was converted into a high-affinity system in the presence of BioMN. BioMNY- Biotin is synthesized by many bacteria, certain archaea, fungi, and plants (reviewed in ref. 2). Several metabolic routes seem to exist for the synthesis of the intermediate pimeloyl-CoA, which then is converted into biotin in a four-step path encoded by the universal genes bioF, bioA, bioD, and bioB (3, 4). In plants, the pathway is distributed between the cytosol and the mitochondria. At least the final step, catalyzed by biotin synthase, occurs in mitochondria. This enzyme, a member of the radical SAM enzyme family, inserts a sulfur atom into dethiobiotin in a complex reaction that is linked to mitochondrial iron/sulfur metabolism (2).Biotin uptake has been analyzed in eukaryotes. In mammalian cells, the vitamin is transported across the plasma membrane by a sodium-dependent multivitamin transporter and, at least in certain tissues, by monocarboxylate transporter 1 (1). In the naturally biotin-auxotrophic yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, biotin uptake is mediated by unrelated proton symporters (5). Surprisingly little is known on the mechanisms behind biotin transport into prokaryotic cells, and multiple systems seem to exist. Active transport was observed for Escherichia coli K-12 Ͼ30 years ago (6). Despite extensive experimental work, knowledge of the complete genome sequence, and assignment of the biotin-transport locus to the 75-min genomic region, the gene(s) for the biotin transporter has not yet been identified. Recent studies by Walker and Altman (7) suggest that this system in E. coli and related Gram-negative bacteria not only transports the small vitamin, but in addition facilitates the uptake of biotinylated peptides with chain lengths up to 31 amino acid residues.In 2002, Entcheva et al. (8) reported that mutations in bioM and bioN lead to reduced biotin uptake in Sinorhizobium meliloti. Because the products of these two genes share distinct similarity with CbiO and CbiQ, which are components of prokary...

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“…The unicellular ancestor of Streptophytes was a freshwater biflagellate whose most similar extant relative is in the genus Mesostigma (Bhattacharya et al 1998;Marin and Melkonian 1999;Lemieux et al 2000Lemieux et al , 2007Rodriguez-Ezpeleta et al 2006). Mesotigma does not produce cellulose or any type of cell wall, but instead has calcified scales.…”

Section: The Closest Unicellular Relative Of Land Plantsmentioning

confidence: 99%

Green Algae and the Origins of Multicellularity in the Plant Kingdom

Umen

2014

Cold Spring Harbor Perspectives in Biology

121

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The green lineage of chlorophyte algae and streptophytes form a large and diverse clade with multiple independent transitions to produce multicellular and/or macroscopically complex organization. In this review, I focus on two of the best-studied multicellular groups of green algae: charophytes and volvocines. Charophyte algae are the closest relatives of land plants and encompass the transition from unicellularity to simple multicellularity. Many of the innovations present in land plants have their roots in the cell and developmental biology of charophyte algae. Volvocine algae evolved an independent route to multicellularity that is captured by a graded series of increasing cell-type specialization and developmental complexity. The study of volvocine algae has provided unprecedented insights into the innovations required to achieve multicellularity.

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Ancestral chloroplast genome in Mesostigma viride reveals an early branch of green plant evolution

Cited by 245 publications

References 20 publications

Evolutionary analysis ofArabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus

Evolutionary analysis ofArabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus

Biotin uptake in prokaryotes by solute transporters with an optional ATP-binding cassette-containing module

Green Algae and the Origins of Multicellularity in the Plant Kingdom

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