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Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales

A characteristic feature of the order Rhodobacterales is the presence of a large number of photoautotrophic and photoheterotrophic species containing bacteriochlorophyll. Interestingly, these phototrophic species are phylogenetically mixed with chemotrophs. To better understand the origin of such va...

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Autores principales: Kopejtka, Karel, Tomasch, Jürgen, Zeng, Yonghui, Tichý, Martin, Sorokin, Dimitry Y., Koblížek, Michal
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5553392/
https://www.ncbi.nlm.nih.gov/pubmed/28810712
http://dx.doi.org/10.1093/gbe/evx141
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author Kopejtka, Karel
Tomasch, Jürgen
Zeng, Yonghui
Tichý, Martin
Sorokin, Dimitry Y.
Koblížek, Michal
author_facet Kopejtka, Karel
Tomasch, Jürgen
Zeng, Yonghui
Tichý, Martin
Sorokin, Dimitry Y.
Koblížek, Michal
author_sort Kopejtka, Karel
collection PubMed
description A characteristic feature of the order Rhodobacterales is the presence of a large number of photoautotrophic and photoheterotrophic species containing bacteriochlorophyll. Interestingly, these phototrophic species are phylogenetically mixed with chemotrophs. To better understand the origin of such variability, we sequenced the genomes of three closely related haloalkaliphilic species, differing in their phototrophic capacity and oxygen preference: the photoheterotrophic and facultatively anaerobic bacterium Rhodobaca barguzinensis, aerobic photoheterotroph Roseinatronobacter thiooxidans, and aerobic heterotrophic bacterium Natronohydrobacter thiooxidans. These three haloalcaliphilic species are phylogenetically related and share many common characteristics with the Rhodobacter species, forming together the Rhodobacter-Rhodobaca (RR) group. A comparative genomic analysis showed close homology of photosynthetic proteins and similarity in photosynthesis gene organization among the investigated phototrophic RR species. On the other hand, Rhodobaca barguzinensis and Roseinatronobacter thiooxidans lack an inorganic carbon fixation pathway and outer light-harvesting genes. This documents the reduction of their photosynthetic machinery towards a mostly photoheterotrophic lifestyle. Moreover, both phototrophic species contain 5-aminolevulinate synthase (encoded by the hemA gene) incorporated into their photosynthesis gene clusters, which seems to be a common feature of all aerobic anoxygenic phototrophic Alphaproteobacteria. Interestingly, the chrR-rpoE (sigma24) operon, which is part of singlet oxygen defense in phototrophic species, was found in the heterotrophic strain Natronohydrobacter thiooxidans. This suggests that this organism evolved from a photoheterotrophic ancestor through the loss of its photosynthesis genes. The overall evolution of phototrophy among the haloalkaliphilic members of the RR group is discussed.
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spelling pubmed-55533922017-08-29 Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales Kopejtka, Karel Tomasch, Jürgen Zeng, Yonghui Tichý, Martin Sorokin, Dimitry Y. Koblížek, Michal Genome Biol Evol Research Article A characteristic feature of the order Rhodobacterales is the presence of a large number of photoautotrophic and photoheterotrophic species containing bacteriochlorophyll. Interestingly, these phototrophic species are phylogenetically mixed with chemotrophs. To better understand the origin of such variability, we sequenced the genomes of three closely related haloalkaliphilic species, differing in their phototrophic capacity and oxygen preference: the photoheterotrophic and facultatively anaerobic bacterium Rhodobaca barguzinensis, aerobic photoheterotroph Roseinatronobacter thiooxidans, and aerobic heterotrophic bacterium Natronohydrobacter thiooxidans. These three haloalcaliphilic species are phylogenetically related and share many common characteristics with the Rhodobacter species, forming together the Rhodobacter-Rhodobaca (RR) group. A comparative genomic analysis showed close homology of photosynthetic proteins and similarity in photosynthesis gene organization among the investigated phototrophic RR species. On the other hand, Rhodobaca barguzinensis and Roseinatronobacter thiooxidans lack an inorganic carbon fixation pathway and outer light-harvesting genes. This documents the reduction of their photosynthetic machinery towards a mostly photoheterotrophic lifestyle. Moreover, both phototrophic species contain 5-aminolevulinate synthase (encoded by the hemA gene) incorporated into their photosynthesis gene clusters, which seems to be a common feature of all aerobic anoxygenic phototrophic Alphaproteobacteria. Interestingly, the chrR-rpoE (sigma24) operon, which is part of singlet oxygen defense in phototrophic species, was found in the heterotrophic strain Natronohydrobacter thiooxidans. This suggests that this organism evolved from a photoheterotrophic ancestor through the loss of its photosynthesis genes. The overall evolution of phototrophy among the haloalkaliphilic members of the RR group is discussed. Oxford University Press 2017-07-27 /pmc/articles/PMC5553392/ /pubmed/28810712 http://dx.doi.org/10.1093/gbe/evx141 Text en © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com
spellingShingle Research Article
Kopejtka, Karel
Tomasch, Jürgen
Zeng, Yonghui
Tichý, Martin
Sorokin, Dimitry Y.
Koblížek, Michal
Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title_full Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title_fullStr Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title_full_unstemmed Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title_short Genomic Analysis of the Evolution of Phototrophy among Haloalkaliphilic Rhodobacterales
title_sort genomic analysis of the evolution of phototrophy among haloalkaliphilic rhodobacterales
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5553392/
https://www.ncbi.nlm.nih.gov/pubmed/28810712
http://dx.doi.org/10.1093/gbe/evx141
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