The plastid ancestor originated among one of the major cyanobacterial lineages

Alda, Jesús A. G. Ochoa de; Esteban, Rocío; Diago, María Luz; Houmard, Jean

doi:10.1038/ncomms5937

Cited by 76 publications

(89 citation statements)

References 59 publications

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“…To determine whether dnaA is universally required for DNA replication, we constructed dnaA deletion Diversification of cyanobacterial DNA replication R Ohbayashi et al mutants in model cyanobacteria Synechocystis and Anabaena that are more closely related to chloroplasts than S. elongatus, as shown in a phylogenetic tree (Turner et al, 1999;Falcon et al, 2010;Shih et al, 2013;Ochoa de Alda et al, 2014) (Figure 5a and Supplementary Figure S6). We readily obtained dnaA deletion mutants using Synechocystis and Anabaena, in contrast to S. elongatus.…”

Section: Dnaa Is Not Essential For Dna Replication and Cell Growth Inmentioning

confidence: 99%

“…PCC 7120 (filamentous) (hereafter S. elongatus, Synechocystis and Anabaena), have been used as model organisms for the study of cyanobacterial physiology such as photosynthesis, circadian rhythm, nitrate fixation and development (Herrero and Flores, 2008). Molecular phylogenetic analysis of DNA sequence converge to a monophyletic origin for plastid (Criscuolo and Gribaldo, 2011;Shih et al, 2013;Li et al, 2014;Ochoa de Alda et al, 2014), meaning that the plastid originated from a single primary endosymbiosis in which a heterotrophic protist engulfed and retained a cyanobacterium in its cytoplasm. However, the identification of the nearest current cyanobacterial species remains controversial (Deusch et al, 2008;Criscuolo and Gribaldo, 2011;Shih et al, 2013;Li et al, 2014;Ochoa de Alda et al, 2014) and then characteristics of the ancestral cyanobacterium are largely unclear.…”

Section: Introductionmentioning

confidence: 99%

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Diversification of DnaA dependency for DNA replication in cyanobacterial evolution

et al. 2015

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Regulating DNA replication is essential for all living cells. The DNA replication initiation factor DnaA is highly conserved in prokaryotes and is required for accurate initiation of chromosomal replication at oriC. DnaA-independent free-living bacteria have not been identified. The dnaA gene is absent in plastids and some symbiotic bacteria, although it is not known when or how DnaA-independent mechanisms were acquired. Here, we show that the degree of dependency of DNA replication on DnaA varies among cyanobacterial species. Deletion of the dnaA gene in Synechococcus elongatus PCC 7942 shifted DNA replication from oriC to a different site as a result of the integration of an episomal plasmid. Moreover, viability during the stationary phase was higher in dnaA disruptants than in wild-type cells. Deletion of dnaA did not affect DNA replication or cell growth in Synechocystis sp. PCC 6803 or Anabaena sp. PCC 7120, indicating that functional dependency on DnaA was already lost in some nonsymbiotic cyanobacterial lineages during diversification. Therefore, we proposed that cyanobacteria acquired DnaA-independent replication mechanisms before symbiosis and such an ancestral cyanobacterium was the sole primary endosymbiont to form a plastid precursor.

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Section: Dnaa Is Not Essential For Dna Replication and Cell Growth Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Diversification of DnaA dependency for DNA replication in cyanobacterial evolution

et al. 2015

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“…It is widely accepted that the mitochondria found across eukaryotes are related back to a single common α-proteobacterial ancestor (68) and that the plastids resulted from a single cyanobacterial infection (69). What is less clear is what happened before these endosymbiont lineages were fixed into organelles.…”

Section: Diversity Of Intra-tremblaya Symbiont Genomes Suggests Multiplementioning

confidence: 99%

Repeated replacement of an intrabacterial symbiont in the tripartite nested mealybug symbiosis

Husník

McCutcheon

2016

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

232

279

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Stable endosymbiosis of a bacterium into a host cell promotes cellular and genomic complexity. The mealybug Planococcus citri has two bacterial endosymbionts with an unusual nested arrangement: the γ-proteobacterium Moranella endobia lives in the cytoplasm of the β-proteobacterium Tremblaya princeps. These two bacteria, along with genes horizontally transferred from other bacteria to the P. citri genome, encode gene sets that form an interdependent metabolic patchwork. Here, we test the stability of this three-way symbiosis by sequencing host and symbiont genomes for five diverse mealybug species and find marked fluidity over evolutionary time. Although Tremblaya is the result of a single infection in the ancestor of mealybugs, the γ-proteobacterial symbionts result from multiple replacements of inferred different ages from related but distinct bacterial lineages. Our data show that symbiont replacement can happen even in the most intricate symbiotic arrangements and that preexisting horizontally transferred genes can remain stable on genomes in the face of extensive symbiont turnover.Sodalis | organelle | horizontal gene transfer | scale insect

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“…The gene for Tic21 is also absent from two studied Gleobacter species, which often take basal position to the rest cyanobacteria in phylogenetic trees [36][37][38], suggesting that lack of this gene might have characterised the ancestor of all cyanobacteria. Because no homolog to the crucial outer membrane translocon Toc75 was found in the two chromatophore genomes and the Paulinella nuclear genome [16], the discovery of homologs to its two receptors, Toc34 and Toc159, was much unexpected (Fig.…”

Section: ≤10mentioning

confidence: 99%

Protein translocons in photosynthetic organelles of Paulinella chromatophora

Gagat

Mackiewicz

2014

Acta Soc Bot Pol

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The rhizarian amoeba Paulinella chromatophora harbors two photosynthetic cyanobacterial endosymbionts (chromatophores), acquired independently of primary plastids of glaucophytes, red algae and green plants. These endosymbionts have lost many essential genes, and transferred substantial number of genes to the host nuclear genome via endosymbiotic gene transfer (EGT), including those involved in photosynthesis. This indicates that, similar to primary plastids, Paulinella endosymbionts must have evolved a transport system to import their EGT-derived proteins. This system involves vesicular trafficking to the outer chromatophore membrane and presumably a simplified Tic-like complex at the inner chromatophore membrane. Since both sequenced Paulinella strains have been shown to undergo differential plastid gene losses, they do not have to possess the same set of Toc and Tic homologs. We searched the genome of Paulinella FK01 strain for potential Toc and Tic homologs, and compared the results with the data obtained for Paulinella CCAC 0185 strain, and 72 cyanobacteria, eight Archaeplastida as well as some other bacteria. Our studies revealed that chromatophore genomes from both Paulinella strains encode the same set of translocons that could potentially create a simplified but fully-functional Tic-like complex at the inner chromatophore membranes. The common maintenance of the same set of translocon proteins in two Paulinella strains suggests a similar import mechanism and/or supports the proposed model of protein import. Moreover, we have discovered a new putative Tic component, Tic62, a redox sensor protein not identified in previous comparative studies of Paulinella translocons.

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The plastid ancestor originated among one of the major cyanobacterial lineages

Cited by 76 publications

References 59 publications

Diversification of DnaA dependency for DNA replication in cyanobacterial evolution

Diversification of DnaA dependency for DNA replication in cyanobacterial evolution

Repeated replacement of an intrabacterial symbiont in the tripartite nested mealybug symbiosis

Protein translocons in photosynthetic organelles of Paulinella chromatophora

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