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Ślesak I, Ślesak H. From cyanobacteria and cyanophages to chloroplasts: the fate of the genomes of oxyphototrophs and the genes encoding photosystem II proteins. THE NEW PHYTOLOGIST 2024; 242:1055-1067. [PMID: 38439684 DOI: 10.1111/nph.19633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 02/02/2024] [Indexed: 03/06/2024]
Abstract
Chloroplasts are the result of endosymbiosis of cyanobacterial organisms with proto-eukaryotes. The psbA, psbD and psbO genes are present in all oxyphototrophs and encode the D1/D2 proteins of photosystem II (PSII) and PsbO, respectively. PsbO is a peripheral protein that stabilizes the O2-evolving complex in PSII. Of these genes, psbA and psbD remained in the chloroplastic genome, while psbO was transferred to the nucleus. The genomes of selected cyanobacteria, chloroplasts and cyanophages carrying psbA and psbD, respectively, were analysed. The highest density of genes and coding sequences (CDSs) was estimated for the genomes of cyanophages, cyanobacteria and chloroplasts. The synonymous mutation rate (rS) of psbA and psbD in chloroplasts remained almost unchanged and is lower than that of psbO. The results indicate that the decreasing genome size in chloroplasts is more similar to the genome reduction observed in contemporary endosymbiotic organisms than in streamlined genomes of free-living cyanobacteria. The rS of atpA, which encodes the α-subunit of ATP synthase in chloroplasts, suggests that psbA and psbD, and to a lesser extent psbO, are ancient and conservative and arose early in the evolution of oxygenic photosynthesis. The role of cyanophages in the evolution of oxyphototrophs and chloroplastic genomes is discussed.
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Affiliation(s)
- Ireneusz Ślesak
- The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239, Kraków, Poland
| | - Halina Ślesak
- Institute of Botany, Faculty of Biology, Jagiellonian University, Gronostajowa 3, 30-387, Kraków, Poland
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2
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He J, Huang Y, Li L, Lin S, Ma M, Wang Y, Lin S. Novel Plastid Genome Characteristics in Fugacium kawagutii and the Trend of Accelerated Evolution of Plastid Proteins in Dinoflagellates. Genome Biol Evol 2024; 16:evad237. [PMID: 38155596 PMCID: PMC10781511 DOI: 10.1093/gbe/evad237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/19/2023] [Accepted: 12/22/2023] [Indexed: 12/30/2023] Open
Abstract
Typical (peridinin-containing) dinoflagellates possess plastid genomes composed of small plasmids named "minicircles". Despite the ecological importance of dinoflagellate photosynthesis in corals and marine ecosystems, the structural characteristics, replication dynamics, and evolutionary forcing of dinoflagellate plastid genomes remain poorly understood. Here, we sequenced the plastid genome of the symbiodiniacean species Fugacium kawagutii and conducted comparative analyses. We identified psbT-coding minicircles, features previously not found in Symbiodiniaceae. The copy number of F. kawagutii minicircles showed a strong diel dynamics, changing between 3.89 and 34.3 copies/cell and peaking in mid-light period. We found that F. kawagutii minicircles are the shortest among all dinoflagellates examined to date. Besides, the core regions of the minicircles are highly conserved within genus in Symbiodiniaceae. Furthermore, the codon usage bias of the plastid genomes in Heterocapsaceae, Amphidiniaceae, and Prorocentraceae species are greatly influenced by selection pressure, and in Pyrocystaceae, Symbiodiniaceae, Peridiniaceae, and Ceratiaceae species are influenced by both natural selection pressure and mutation pressure, indicating a family-level distinction in codon usage evolution in dinoflagellates. Phylogenetic analysis using 12 plastid-encoded proteins and five nucleus-encoded plastid proteins revealed accelerated evolution trend of both plastid- and nucleus-encoded plastid proteins in peridinin- and fucoxanthin-dinoflagellate plastids compared to plastid proteins of nondinoflagellate algae. These findings shed new light on the structure and evolution of plastid genomes in dinoflagellates, which will facilitate further studies on the evolutionary forcing and function of the diverse dinoflagellate plastids. The accelerated evolution documented here suggests plastid-encoded sequences are potentially useful for resolving closely related dinoflagellates.
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Affiliation(s)
- Jiamin He
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Yulin Huang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Ling Li
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Sitong Lin
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Minglei Ma
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Yujie Wang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
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3
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Amario M, Villela LB, Jardim-Messeder D, Silva-Lima AW, Rosado PM, de Moura RL, Sachetto-Martins G, Chaloub RM, Salomon PS. Physiological response of Symbiodiniaceae to thermal stress: Reactive oxygen species, photosynthesis, and relative cell size. PLoS One 2023; 18:e0284717. [PMID: 37535627 PMCID: PMC10399794 DOI: 10.1371/journal.pone.0284717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 04/06/2023] [Indexed: 08/05/2023] Open
Abstract
This study investigates the physiological response to heat stress of three genetically different Symbiodiniaceae strains isolated from the scleractinian coral Mussismilia braziliensis, endemic of the Abrolhos Bank, Brazil. Cultures of two Symbiodinium sp. and one Cladocopium sp. were exposed to a stepwise increase in temperature (2°C every second day) ranging from 26°C (modal temperature in Abrolhos) to 32°C (just above the maximum temperature registered in Abrolhos during the third global bleaching event-TGBE). After the cultures reached their final testing temperature, reactive oxygen species (ROS) production, single cell attributes (relative cell size and chlorophyll fluorescence), and photosynthetic efficiency (effective (Y(II)) and maximum (Fv/Fm) quantum yields) were measured within 4 h and 72 h. Non-photochemical coefficient (NPQ) was estimated based on fluorescence values. Population average ROS production was variable across strains and exposure times, reaching up a 2-fold increase at 32°C in one of the Symbiodinium sp. strains. A marked intrapopulation difference was observed in ROS production, with 5 to 25% of the cells producing up to 10 times more than the population average, highlighting the importance of single cell approaches to assess population physiology. Average cell size increases at higher temperatures, likely resulting from cell cycle arrest, whereas chlorophyll fluorescence decreased, especially in 4 h, indicating a photoacclimation response. The conditions tested do not seem to have elicited loss of photosynthetic efficiency nor the activation of non-photochemical mechanisms in the cells. Our results unveiled a generalized thermotolerance in three Symbiodiniaceae strains originated from Abrolhos' corals. Inter and intra-specific variability could be detected, likely reflecting the genetic differences among the strains.
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Affiliation(s)
- Michelle Amario
- Laboratório de Fitoplâncton Marinho, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Genética, Rio de Janeiro, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lívia Bonetti Villela
- Laboratório de Fitoplâncton Marinho, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
- Programa de Pós-Graduação em Genética, Rio de Janeiro, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Douglas Jardim-Messeder
- Laboratório de Genômica Funcional e Transdução de Sinal, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Instituto de Biologia, Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biologia Molecular de Plantas, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Arthur Weiss Silva-Lima
- Laboratório de Fitoplâncton Marinho, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Rodrigo Leão de Moura
- Laboratório de Monitoramento da Biodiversidade, Instituto de Biologia SAGE-COPPE, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Gilberto Sachetto-Martins
- Laboratório de Genômica Funcional e Transdução de Sinal, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Instituto de Biologia, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ricardo Moreira Chaloub
- Laboratório de Estudos Aplicados em Fotossíntese, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paulo Sergio Salomon
- Laboratório de Fitoplâncton Marinho, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
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Camus MF, Alexander-Lawrie B, Sharbrough J, Hurst GDD. Inheritance through the cytoplasm. Heredity (Edinb) 2022; 129:31-43. [PMID: 35525886 PMCID: PMC9273588 DOI: 10.1038/s41437-022-00540-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/11/2022] Open
Abstract
Most heritable information in eukaryotic cells is encoded in the nuclear genome, with inheritance patterns following classic Mendelian segregation. Genomes residing in the cytoplasm, however, prove to be a peculiar exception to this rule. Cytoplasmic genetic elements are generally maternally inherited, although there are several exceptions where these are paternally, biparentally or doubly-uniparentally inherited. In this review, we examine the diversity and peculiarities of cytoplasmically inherited genomes, and the broad evolutionary consequences that non-Mendelian inheritance brings. We first explore the origins of vertical transmission and uniparental inheritance, before detailing the vast diversity of cytoplasmic inheritance systems across Eukaryota. We then describe the evolution of genomic organisation across lineages, how this process has been shaped by interactions with the nuclear genome and population genetics dynamics. Finally, we discuss how both nuclear and cytoplasmic genomes have evolved to co-inhabit the same host cell via one of the longest symbiotic processes, and all the opportunities for intergenomic conflict that arise due to divergence in inheritance patterns. In sum, we cannot understand the evolution of eukaryotes without understanding hereditary symbiosis.
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Affiliation(s)
- M Florencia Camus
- Department of Genetics, Evolution and Environment, University College London, London, UK.
| | | | - Joel Sharbrough
- Biology Department, New Mexico Institute of Mining and Technology, Socorro, NM, USA
| | - Gregory D D Hurst
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, England
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5
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González-Pech RA, Stephens TG, Chen Y, Mohamed AR, Cheng Y, Shah S, Dougan KE, Fortuin MDA, Lagorce R, Burt DW, Bhattacharya D, Ragan MA, Chan CX. Comparison of 15 dinoflagellate genomes reveals extensive sequence and structural divergence in family Symbiodiniaceae and genus Symbiodinium. BMC Biol 2021; 19:73. [PMID: 33849527 PMCID: PMC8045281 DOI: 10.1186/s12915-021-00994-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/25/2021] [Indexed: 02/07/2023] Open
Abstract
Background Dinoflagellates in the family Symbiodiniaceae are important photosynthetic symbionts in cnidarians (such as corals) and other coral reef organisms. Breakdown of the coral-dinoflagellate symbiosis due to environmental stress (i.e. coral bleaching) can lead to coral death and the potential collapse of reef ecosystems. However, evolution of Symbiodiniaceae genomes, and its implications for the coral, is little understood. Genome sequences of Symbiodiniaceae remain scarce due in part to their large genome sizes (1–5 Gbp) and idiosyncratic genome features. Results Here, we present de novo genome assemblies of seven members of the genus Symbiodinium, of which two are free-living, one is an opportunistic symbiont, and the remainder are mutualistic symbionts. Integrating other available data, we compare 15 dinoflagellate genomes revealing high sequence and structural divergence. Divergence among some Symbiodinium isolates is comparable to that among distinct genera of Symbiodiniaceae. We also recovered hundreds of gene families specific to each lineage, many of which encode unknown functions. An in-depth comparison between the genomes of the symbiotic Symbiodinium tridacnidorum (isolated from a coral) and the free-living Symbiodinium natans reveals a greater prevalence of transposable elements, genetic duplication, structural rearrangements, and pseudogenisation in the symbiotic species. Conclusions Our results underscore the potential impact of lifestyle on lineage-specific gene-function innovation, genome divergence, and the diversification of Symbiodinium and Symbiodiniaceae. The divergent features we report, and their putative causes, may also apply to other microbial eukaryotes that have undergone symbiotic phases in their evolutionary history. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-00994-6.
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Affiliation(s)
- Raúl A González-Pech
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,Present address: Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA.
| | - Timothy G Stephens
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Present address: Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Yibi Chen
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Amin R Mohamed
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Queensland Bioscience Precinct, St Lucia, QLD, 4072, Australia.,Present address: Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Yuanyuan Cheng
- UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia.,Present address: School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Sarah Shah
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Katherine E Dougan
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Michael D A Fortuin
- Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Rémi Lagorce
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,École Polytechnique Universitaire de l'Université de Nice, Université Nice-Sophia-Antipolis, 06410, Nice, Provence-Alpes-Côte d'Azur, France
| | - David W Burt
- UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Mark A Ragan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia. .,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
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6
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Occurrence, Evolution and Specificities of Iron-Sulfur Proteins and Maturation Factors in Chloroplasts from Algae. Int J Mol Sci 2021; 22:ijms22063175. [PMID: 33804694 PMCID: PMC8003979 DOI: 10.3390/ijms22063175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/25/2021] [Accepted: 03/17/2021] [Indexed: 01/08/2023] Open
Abstract
Iron-containing proteins, including iron-sulfur (Fe-S) proteins, are essential for numerous electron transfer and metabolic reactions. They are present in most subcellular compartments. In plastids, in addition to sustaining the linear and cyclic photosynthetic electron transfer chains, Fe-S proteins participate in carbon, nitrogen, and sulfur assimilation, tetrapyrrole and isoprenoid metabolism, and lipoic acid and thiamine synthesis. The synthesis of Fe-S clusters, their trafficking, and their insertion into chloroplastic proteins necessitate the so-called sulfur mobilization (SUF) protein machinery. In the first part, we describe the molecular mechanisms that allow Fe-S cluster synthesis and insertion into acceptor proteins by the SUF machinery and analyze the occurrence of the SUF components in microalgae, focusing in particular on the green alga Chlamydomonas reinhardtii. In the second part, we describe chloroplastic Fe-S protein-dependent pathways that are specific to Chlamydomonas or for which Chlamydomonas presents specificities compared to terrestrial plants, putting notable emphasis on the contribution of Fe-S proteins to chlorophyll synthesis in the dark and to the fermentative metabolism. The occurrence and evolutionary conservation of these enzymes and pathways have been analyzed in all supergroups of microalgae performing oxygenic photosynthesis.
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7
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Provorov NA. Symbiotic Models for Reconstruction of Organellogenesis. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421010117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Schön ME, Eme L, Ettema TJG. PhyloMagnet: fast and accurate screening of short-read meta-omics data using gene-centric phylogenetics. Bioinformatics 2020; 36:1718-1724. [PMID: 31647547 PMCID: PMC7703773 DOI: 10.1093/bioinformatics/btz799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/20/2019] [Accepted: 10/23/2019] [Indexed: 11/18/2022] Open
Abstract
Motivation Metagenomic and metatranscriptomic sequencing have become increasingly popular tools for producing massive amounts of short-read data, often used for the reconstruction of draft genomes or the detection of (active) genes in microbial communities. Unfortunately, sequence assemblies of such datasets generally remain a computationally challenging task. Frequently, researchers are only interested in a specific group of organisms or genes; yet, the assembly of multiple datasets only to identify candidate sequences for a specific question is sometimes prohibitively slow, forcing researchers to select a subset of available datasets to address their question. Here, we present PhyloMagnet, a workflow to screen meta-omics datasets for taxa and genes of interest using gene-centric assembly and phylogenetic placement of sequences. Results Using PhyloMagnet, we could identify up to 87% of the genera in an in vitro mock community with variable abundances, while the false positive predictions per single gene tree ranged from 0 to 23%. When applied to a group of metagenomes for which a set of metagenome assembled genomes (MAGs) have been published, we could detect the majority of the taxonomic labels that the MAGs had been annotated with. In a metatranscriptomic setting, the phylogenetic placement of assembled contigs corresponds to that of transcripts obtained from transcriptome assembly. Availability and implementation PhyloMagnet is built using Nextflow, available at github.com/maxemil/PhyloMagnet and is developed and tested on Linux. It is released under the open source GNU GPL licence and documentation is available at phylomagnet.readthedocs.io. Version 0.5 of PhyloMagnet was used for all benchmarking experiments. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Max E Schön
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, SE 75123, Sweden
| | - Laura Eme
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, SE 75123, Sweden.,Ecology, Systematics and Evolution, CNRS, Paris-Sud University, 91400 Orsay, France
| | - Thijs J G Ettema
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Uppsala, SE 75123, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen 6708 WE, The Netherlands
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9
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Stephens TG, González-Pech RA, Cheng Y, Mohamed AR, Burt DW, Bhattacharya D, Ragan MA, Chan CX. Genomes of the dinoflagellate Polarella glacialis encode tandemly repeated single-exon genes with adaptive functions. BMC Biol 2020; 18:56. [PMID: 32448240 PMCID: PMC7245778 DOI: 10.1186/s12915-020-00782-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 04/20/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Dinoflagellates are taxonomically diverse and ecologically important phytoplankton that are ubiquitously present in marine and freshwater environments. Mostly photosynthetic, dinoflagellates provide the basis of aquatic primary production; most taxa are free-living, while some can form symbiotic and parasitic associations with other organisms. However, knowledge of the molecular mechanisms that underpin the adaptation of these organisms to diverse ecological niches is limited by the scarce availability of genomic data, partly due to their large genome sizes estimated up to 250 Gbp. Currently available dinoflagellate genome data are restricted to Symbiodiniaceae (particularly symbionts of reef-building corals) and parasitic lineages, from taxa that have smaller genome size ranges, while genomic information from more diverse free-living species is still lacking. RESULTS Here, we present two draft diploid genome assemblies of the free-living dinoflagellate Polarella glacialis, isolated from the Arctic and Antarctica. We found that about 68% of the genomes are composed of repetitive sequence, with long terminal repeats likely contributing to intra-species structural divergence and distinct genome sizes (3.0 and 2.7 Gbp). For each genome, guided using full-length transcriptome data, we predicted > 50,000 high-quality protein-coding genes, of which ~40% are in unidirectional gene clusters and ~25% comprise single exons. Multi-genome comparison unveiled genes specific to P. glacialis and a common, putatively bacterial origin of ice-binding domains in cold-adapted dinoflagellates. CONCLUSIONS Our results elucidate how selection acts within the context of a complex genome structure to facilitate local adaptation. Because most dinoflagellate genes are constitutively expressed, Polarella glacialis has enhanced transcriptional responses via unidirectional, tandem duplication of single-exon genes that encode functions critical to survival in cold, low-light polar environments. These genomes provide a foundational reference for future research on dinoflagellate evolution.
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Affiliation(s)
- Timothy G Stephens
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Present Address: Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Raúl A González-Pech
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Present address: Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Yuanyuan Cheng
- UQ Genomics Initiative, The University of Queensland, Brisbane, QLD, 4072, Australia.,Present Address: Faculty of Science, School of Life and Environmental Sciences, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - Amin R Mohamed
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Queensland Bioscience Precinct, Brisbane, QLD, 4067, Australia
| | - David W Burt
- UQ Genomics, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Mark A Ragan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia. .,Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD, 4072, Australia.
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10
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Insights on the genetic repertoire of the coral Mussismilia braziliensis endosymbiont Symbiodinium. Symbiosis 2020. [DOI: 10.1007/s13199-020-00664-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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11
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There Is Treasure Everywhere: Reductive Plastid Evolution in Apicomplexa in Light of Their Close Relatives. Biomolecules 2019; 9:biom9080378. [PMID: 31430853 PMCID: PMC6722601 DOI: 10.3390/biom9080378] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 02/05/2023] Open
Abstract
The phylum Apicomplexa (Alveolates) comprises a group of host-associated protists, predominately intracellular parasites, including devastating parasites like Plasmodium falciparum, the causative agent of malaria. One of the more fascinating characteristics of Apicomplexa is their highly reduced (and occasionally lost) remnant plastid, termed the apicoplast. Four core metabolic pathways are retained in the apicoplast: heme synthesis, iron–sulfur cluster synthesis, isoprenoid synthesis, and fatty acid synthesis. It has been suggested that one or more of these pathways are essential for plastid and plastid genome retention. The past decade has witnessed the discovery of several apicomplexan relatives, and next-generation sequencing efforts are revealing that they retain variable plastid metabolic capacities. These data are providing clues about the core genes and pathways of reduced plastids, while at the same time further confounding our view on the evolutionary history of the apicoplast. Here, we examine the evolutionary history of the apicoplast, explore plastid metabolism in Apicomplexa and their close relatives, and propose that the differences among reduced plastids result from a game of endosymbiotic roulette. Continued exploration of the Apicomplexa and their relatives is sure to provide new insights into the evolution of the apicoplast and apicomplexans as a whole.
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12
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Dorrell RG, Nisbet RER, Barbrook AC, Rowden SJL, Howe CJ. Integrated Genomic and Transcriptomic Analysis of the Peridinin Dinoflagellate Amphidinium carterae Plastid. Protist 2019; 170:358-373. [PMID: 31415953 DOI: 10.1016/j.protis.2019.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 01/17/2023]
Abstract
The plastid genomes of peridinin-containing dinoflagellates are highly unusual, possessing very few genes, which are located on small chromosomal elements termed "minicircles". These minicircles may contain genes, or no recognisable coding information. Transcripts produced from minicircles may undergo unusual processing events, such as the addition of a 3' poly(U) tail. To date, little is known about the genetic or transcriptional diversity of non-coding sequences in peridinin dinoflagellate plastids. These sequences include empty minicircles, and regions of non-coding DNA in coding minicircles. Here, we present an integrated plastid genome and transcriptome for the model peridinin dinoflagellate Amphidinium carterae, identifying a previously undescribed minicircle. We also profile transcripts covering non-coding regions of the psbA and petB/atpA minicircles. We present evidence that antisense transcripts are produced within the A. carterae plastid, but show that these transcripts undergo different end cleavage events from sense transcripts, and do not receive 3' poly(U) tails. The difference in processing events between sense and antisense transcripts may enable the removal of non-coding transcripts from peridinin dinoflagellate plastid transcript pools.
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Affiliation(s)
| | - R Ellen R Nisbet
- Department of Biochemistry, University of Cambridge, United Kingdom
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13
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Nimmo IC, Barbrook AC, Lassadi I, Chen JE, Geisler K, Smith AG, Aranda M, Purton S, Waller RF, Nisbet RER, Howe CJ. Genetic transformation of the dinoflagellate chloroplast. eLife 2019; 8:45292. [PMID: 31317866 PMCID: PMC6639071 DOI: 10.7554/elife.45292] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 07/06/2019] [Indexed: 01/02/2023] Open
Abstract
Coral reefs are some of the most important and ecologically diverse marine environments. At the base of the reef ecosystem are dinoflagellate algae, which live symbiotically within coral cells. Efforts to understand the relationship between alga and coral have been greatly hampered by the lack of an appropriate dinoflagellate genetic transformation technology. By making use of the plasmid-like fragmented chloroplast genome, we have introduced novel genetic material into the dinoflagellate chloroplast genome. We have shown that the introduced genes are expressed and confer the expected phenotypes. Genetically modified cultures have been grown for 1 year with subculturing, maintaining the introduced genes and phenotypes. This indicates that cells continue to divide after transformation and that the transformation is stable. This is the first report of stable chloroplast transformation in dinoflagellate algae.
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Affiliation(s)
- Isabel C Nimmo
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Adrian C Barbrook
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Imen Lassadi
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Jit Ern Chen
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.,Jeffrey Sachs Center on Sustainable Development, Sunway University, Bandar Sunway, Malaysia
| | - Katrin Geisler
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Manuel Aranda
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Saul Purton
- Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Ross F Waller
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - R Ellen R Nisbet
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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14
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Kwong WK, Del Campo J, Mathur V, Vermeij MJA, Keeling PJ. A widespread coral-infecting apicomplexan with chlorophyll biosynthesis genes. Nature 2019; 568:103-107. [PMID: 30944491 DOI: 10.1038/s41586-019-1072-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 03/06/2019] [Indexed: 12/22/2022]
Abstract
Apicomplexa is a group of obligate intracellular parasites that includes the causative agents of human diseases such as malaria and toxoplasmosis. Apicomplexans evolved from free-living phototrophic ancestors, but how this transition to parasitism occurred remains unknown. One potential clue lies in coral reefs, of which environmental DNA surveys have uncovered several lineages of uncharacterized basally branching apicomplexans1,2. Reef-building corals have a well-studied symbiotic relationship with photosynthetic Symbiodiniaceae dinoflagellates (for example, Symbiodinium3), but the identification of other key microbial symbionts of corals has proven to be challenging4,5. Here we use community surveys, genomics and microscopy analyses to identify an apicomplexan lineage-which we informally name 'corallicolids'-that was found at a high prevalence (over 80% of samples, 70% of genera) across all major groups of corals. Corallicolids were the second most abundant coral-associated microeukaryotes after the Symbiodiniaceae, and are therefore core members of the coral microbiome. In situ fluorescence and electron microscopy confirmed that corallicolids live intracellularly within the tissues of the coral gastric cavity, and that they possess apicomplexan ultrastructural features. We sequenced the genome of the corallicolid plastid, which lacked all genes for photosystem proteins; this indicates that corallicolids probably contain a non-photosynthetic plastid (an apicoplast6). However, the corallicolid plastid differs from all other known apicoplasts because it retains the four ancestral genes that are involved in chlorophyll biosynthesis. Corallicolids thus share characteristics with both their parasitic and their free-living relatives, which suggests that they are evolutionary intermediates and implies the existence of a unique biochemistry during the transition from phototrophy to parasitism.
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Affiliation(s)
- Waldan K Kwong
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Javier Del Campo
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Varsha Mathur
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mark J A Vermeij
- Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands.,CARMABI Foundation, Willemstad, Curaçao, The Netherlands
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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15
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Su HJ, Barkman TJ, Hao W, Jones SS, Naumann J, Skippington E, Wafula EK, Hu JM, Palmer JD, dePamphilis CW. Novel genetic code and record-setting AT-richness in the highly reduced plastid genome of the holoparasitic plant Balanophora. Proc Natl Acad Sci U S A 2019; 116:934-943. [PMID: 30598433 PMCID: PMC6338844 DOI: 10.1073/pnas.1816822116] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plastid genomes (plastomes) vary enormously in size and gene content among the many lineages of nonphotosynthetic plants, but key lineages remain unexplored. We therefore investigated plastome sequence and expression in the holoparasitic and morphologically bizarre Balanophoraceae. The two Balanophora plastomes examined are remarkable, exhibiting features rarely if ever seen before in plastomes or in any other genomes. At 15.5 kb in size and with only 19 genes, they are among the most reduced plastomes known. They have no tRNA genes for protein synthesis, a trait found in only three other plastid lineages, and thus Balanophora plastids must import all tRNAs needed for translation. Balanophora plastomes are exceptionally compact, with numerous overlapping genes, highly reduced spacers, loss of all cis-spliced introns, and shrunken protein genes. With A+T contents of 87.8% and 88.4%, the Balanophora genomes are the most AT-rich genomes known save for a single mitochondrial genome that is merely bloated with AT-rich spacer DNA. Most plastid protein genes in Balanophora consist of ≥90% AT, with several between 95% and 98% AT, resulting in the most biased codon usage in any genome described to date. A potential consequence of its radical compositional evolution is the novel genetic code used by Balanophora plastids, in which TAG has been reassigned from stop to tryptophan. Despite its many exceptional properties, the Balanophora plastome must be functional because all examined genes are transcribed, its only intron is correctly trans-spliced, and its protein genes, although highly divergent, are evolving under various degrees of selective constraint.
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Affiliation(s)
- Huei-Jiun Su
- Department of Earth and Life Sciences, University of Taipei, 100 Taipei, Taiwan
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | - Todd J Barkman
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008
| | - Weilong Hao
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
| | - Samuel S Jones
- Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802
| | - Julia Naumann
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | | | - Eric K Wafula
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | - Jer-Ming Hu
- Institute of Ecology and Evolutionary Biology, National Taiwan University, 106 Taipei, Taiwan
| | - Jeffrey D Palmer
- Department of Biology, Indiana University, Bloomington, IN 47405;
| | - Claude W dePamphilis
- Department of Biology, Pennsylvania State University, University Park, PA 16802;
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
- Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802
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16
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Sloan DB, Warren JM, Williams AM, Wu Z, Abdel-Ghany SE, Chicco AJ, Havird JC. Cytonuclear integration and co-evolution. Nat Rev Genet 2018; 19:635-648. [PMID: 30018367 PMCID: PMC6469396 DOI: 10.1038/s41576-018-0035-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The partitioning of genetic material between the nucleus and cytoplasmic (mitochondrial and plastid) genomes within eukaryotic cells necessitates coordinated integration between these genomic compartments, with important evolutionary and biomedical implications. Classic questions persist about the pervasive reduction of cytoplasmic genomes via a combination of gene loss, transfer and functional replacement - and yet why they are almost always retained in some minimal form. One striking consequence of cytonuclear integration is the existence of 'chimeric' enzyme complexes composed of subunits encoded in two different genomes. Advances in structural biology and comparative genomics are yielding important insights into the evolution of such complexes, including correlated sequence changes and recruitment of novel subunits. Thus, chimeric cytonuclear complexes provide a powerful window into the mechanisms of molecular co-evolution.
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Affiliation(s)
- Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins, CO, USA.
| | - Jessica M Warren
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Alissa M Williams
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Zhiqiang Wu
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | | | - Adam J Chicco
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Justin C Havird
- Department of Biology, Colorado State University, Fort Collins, CO, USA
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17
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Liu H, Stephens TG, González-Pech RA, Beltran VH, Lapeyre B, Bongaerts P, Cooke I, Aranda M, Bourne DG, Forêt S, Miller DJ, van Oppen MJH, Voolstra CR, Ragan MA, Chan CX. Symbiodinium genomes reveal adaptive evolution of functions related to coral-dinoflagellate symbiosis. Commun Biol 2018; 1:95. [PMID: 30271976 PMCID: PMC6123633 DOI: 10.1038/s42003-018-0098-3] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/21/2018] [Indexed: 12/20/2022] Open
Abstract
Symbiosis between dinoflagellates of the genus Symbiodinium and reef-building corals forms the trophic foundation of the world’s coral reef ecosystems. Here we present the first draft genome of Symbiodinium goreaui (Clade C, type C1: 1.03 Gbp), one of the most ubiquitous endosymbionts associated with corals, and an improved draft genome of Symbiodinium kawagutii (Clade F, strain CS-156: 1.05 Gbp) to further elucidate genomic signatures of this symbiosis. Comparative analysis of four available Symbiodinium genomes against other dinoflagellate genomes led to the identification of 2460 nuclear gene families (containing 5% of Symbiodinium genes) that show evidence of positive selection, including genes involved in photosynthesis, transmembrane ion transport, synthesis and modification of amino acids and glycoproteins, and stress response. Further, we identify extensive sets of genes for meiosis and response to light stress. These draft genomes provide a foundational resource for advancing our understanding of Symbiodinium biology and the coral-algal symbiosis. Huanle Liu et al. report draft genomes of two Symbiodinium species, one from the most dominant type of symbionts in reef-building corals. They find evidence of positive selection in genes related to stress response, meiosis and other traits required for forming successful symbiotic relationships.
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Affiliation(s)
- Huanle Liu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Timothy G Stephens
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Raúl A González-Pech
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Victor H Beltran
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia
| | - Bruno Lapeyre
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.,Department of Molecular and Cell Biology, James Cook University, Townsville, QLD, 4811, Australia.,Laboratoire d'excellence CORAIL, Centre de Recherches Insulaires et Observatoire de l'Environnement, Moorea, 98729, French Polynesia
| | - Pim Bongaerts
- Global Change Institute, The University of Queensland, Brisbane, QLD, 4072, Australia.,Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA, 94118, USA
| | - Ira Cooke
- Department of Molecular and Cell Biology, James Cook University, Townsville, QLD, 4811, Australia
| | - Manuel Aranda
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - David G Bourne
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia.,College of Science and Engineering, James Cook University, Townsville, QLD, 4811, Australia
| | - Sylvain Forêt
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.,Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - David J Miller
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.,Department of Molecular and Cell Biology, James Cook University, Townsville, QLD, 4811, Australia
| | - Madeleine J H van Oppen
- Australian Institute of Marine Science, Townsville, QLD, 4810, Australia.,School of BioSciences, The University of Melbourne, VIC, 3010, Australia
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Mark A Ragan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia. .,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
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18
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19
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Del Cortona A, Leliaert F, Bogaert KA, Turmel M, Boedeker C, Janouškovec J, Lopez-Bautista JM, Verbruggen H, Vandepoele K, De Clerck O. The Plastid Genome in Cladophorales Green Algae Is Encoded by Hairpin Chromosomes. Curr Biol 2017; 27:3771-3782.e6. [PMID: 29199074 DOI: 10.1016/j.cub.2017.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/28/2022]
Abstract
Virtually all plastid (chloroplast) genomes are circular double-stranded DNA molecules, typically between 100 and 200 kb in size and encoding circa 80-250 genes. Exceptions to this universal plastid genome architecture are very few and include the dinoflagellates, where genes are located on DNA minicircles. Here we report on the highly deviant chloroplast genome of Cladophorales green algae, which is entirely fragmented into hairpin chromosomes. Short- and long-read high-throughput sequencing of DNA and RNA demonstrated that the chloroplast genes of Boodlea composita are encoded on 1- to 7-kb DNA contigs with an exceptionally high GC content, each containing a long inverted repeat with one or two protein-coding genes and conserved non-coding regions putatively involved in replication and/or expression. We propose that these contigs correspond to linear single-stranded DNA molecules that fold onto themselves to form hairpin chromosomes. The Boodlea chloroplast genes are highly divergent from their corresponding orthologs, and display an alternative genetic code. The origin of this highly deviant chloroplast genome most likely occurred before the emergence of the Cladophorales, and coincided with an elevated transfer of chloroplast genes to the nucleus. A chloroplast genome that is composed only of linear DNA molecules is unprecedented among eukaryotes, and highlights unexpected variation in plastid genome architecture.
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Affiliation(s)
- Andrea Del Cortona
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium; VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Zwijnaarde, Belgium; Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium
| | - Frederik Leliaert
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium; Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
| | - Kenny A Bogaert
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium
| | - Monique Turmel
- Institut de Biologie Intégrative et des Systèmes, Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, Pavillon Charles-Eugène-Marchand 1030, Avenue de la Médecine, Québec City, QC G1V 0A6, Canada
| | - Christian Boedeker
- School of Biological Sciences, Victoria University of Wellington, New Kirk Building, Kelburn Parade, P.O. Box 600, Wellington 6012, New Zealand
| | - Jan Janouškovec
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Juan M Lopez-Bautista
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35484-0345, USA
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Professors Walk, Melbourne, VIC 3010, Australia
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium; VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Zwijnaarde, Belgium; Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium
| | - Olivier De Clerck
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium.
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20
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Mies M, Sumida PYG, Rädecker N, Voolstra CR. Marine Invertebrate Larvae Associated with Symbiodinium: A Mutualism from the Start? Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00056] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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21
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Gierz SL, Forêt S, Leggat W. Transcriptomic Analysis of Thermally Stressed Symbiodinium Reveals Differential Expression of Stress and Metabolism Genes. FRONTIERS IN PLANT SCIENCE 2017; 8:271. [PMID: 28293249 PMCID: PMC5328969 DOI: 10.3389/fpls.2017.00271] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 02/14/2017] [Indexed: 05/29/2023]
Abstract
Endosymbioses between dinoflagellate algae (Symbiodinium sp.) and scleractinian coral species form the foundation of coral reef ecosystems. The coral symbiosis is highly susceptible to elevated temperatures, resulting in coral bleaching, where the algal symbiont is released from host cells. This experiment aimed to determine the transcriptional changes in cultured Symbiodinium, to better understand the response of cellular mechanisms under future temperature conditions. Cultures were exposed to elevated temperatures (average 31°C) or control conditions (24.5°C) for a period of 28 days. Whole transcriptome sequencing of Symbiodinium cells on days 4, 19, and 28 were used to identify differentially expressed genes under thermal stress. A large number of genes representing 37.01% of the transcriptome (∼23,654 unique genes, FDR < 0.05) with differential expression were detected at no less than one of the time points. Consistent with previous studies of Symbiodinium gene expression, fold changes across the transcriptome were low, with 92.49% differentially expressed genes at ≤2-fold change. The transcriptional response included differential expression of genes encoding stress response components such as the antioxidant network and molecular chaperones, cellular components such as core photosynthesis machinery, integral light-harvesting protein complexes and enzymes such as fatty acid desaturases. Differential expression of genes encoding glyoxylate cycle enzymes were also found, representing the first report of this in Symbiodinium. As photosynthate transfer from Symbiodinium to coral hosts provides up to 90% of a coral's daily energy requirements, the implications of altered metabolic processes from exposure to thermal stress found in this study on coral-Symbiodinium associations are unknown and should be considered when assessing the stability of the symbiotic relationship under future climate conditions.
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Affiliation(s)
- Sarah L. Gierz
- College of Public Health, Medical and Veterinary Sciences, James Cook University, TownsvilleQLD, Australia
- Comparative Genomics Centre, James Cook University, TownsvilleQLD, Australia
| | - Sylvain Forêt
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, TownsvilleQLD, Australia
- Evolution, Ecology and Genetics, Research School of Biology, Australian National University, CanberraACT, Australia
| | - William Leggat
- College of Public Health, Medical and Veterinary Sciences, James Cook University, TownsvilleQLD, Australia
- Comparative Genomics Centre, James Cook University, TownsvilleQLD, Australia
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, TownsvilleQLD, Australia
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22
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Rouzé H, Lecellier GJ, Saulnier D, Planes S, Gueguen Y, Wirshing HH, Berteaux-Lecellier V. An updated assessment of Symbiodinium spp. that associate with common scleractinian corals from Moorea (French Polynesia) reveals high diversity among background symbionts and a novel finding of clade B. PeerJ 2017; 5:e2856. [PMID: 28168100 PMCID: PMC5289445 DOI: 10.7717/peerj.2856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 12/02/2016] [Indexed: 12/27/2022] Open
Abstract
The adaptative bleaching hypothesis (ABH) states that, depending on the symbiotic flexibility of coral hosts (i.e., the ability of corals to “switch” or “shuffle” their algal symbionts), coral bleaching can lead to a change in the composition of their associated Symbiodinium community and, thus, contribute to the coral’s overall survival. In order to determine the flexibility of corals, molecular tools are required to provide accurate species delineations and to detect low levels of coral-associated Symbiodinium. Here, we used highly sensitive quantitative (real-time) PCR (qPCR) technology to analyse five common coral species from Moorea (French Polynesia), previously screened using only traditional molecular methods, to assess the presence of low-abundance (background) Symbiodinium spp. Similar to other studies, each coral species exhibited a strong specificity to a particular clade, irrespective of the environment. In addition, however, each of the five species harboured at least one additional Symbiodinium clade, among clades A–D, at background levels. Unexpectedly, and for the first time in French Polynesia, clade B was detected as a coral symbiont. These results increase the number of known coral-Symbiodinium associations from corals found in French Polynesia, and likely indicate an underestimation of the ability of the corals in this region to associate with and/or “shuffle” different Symbiodinium clades. Altogether our data suggest that corals from French Polynesia may favor a trade-off between optimizing symbioses with a specific Symbiodinium clade(s), maintaining associations with particular background clades that may play a role in the ability of corals to respond to environmental change.
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Affiliation(s)
- Héloïse Rouzé
- PSL CRIOBE USR3278 CNRS-EPHE-UPVD, Labex CORAIL , Papetoai , Moorea , French Polynesia
| | - Gaël J Lecellier
- PSL CRIOBE USR3278 CNRS-EPHE-UPVD, Labex CORAIL, Papetoai, Moorea, French Polynesia; Université de Paris Saclay, Departement de Biologie, Versailles-Saint Quentin, Paris, Versailles Cedex, France; Current affiliation: UMR250/9220 ENTROPIE IRD-CNRS-UR, Labex CORAIL, Promenade Roger-Laroque, Noumea cedex, New Caledonia, France
| | - Denis Saulnier
- UMR241 EIO Ifremer-ILM-IRD-UPF, Labex CORAIL , Taravao , French Polynesia
| | - Serge Planes
- PSL CRIOBE USR3278 CNRS-EPHE-UPVD, Labex CORAIL , Papetoai , Moorea , French Polynesia
| | - Yannick Gueguen
- UMR5244 IHPE, CNRS-Ifremer-UM-UPVD, Université de Montpellier , Montpellier , France
| | - Herman H Wirshing
- Department of Invertebrate Zoology, Smithsonian National Museum of Natural History , Washington, D.C. , USA
| | - Véronique Berteaux-Lecellier
- PSL CRIOBE USR3278 CNRS-EPHE-UPVD, Labex CORAIL, Papetoai, Moorea, French Polynesia; Current affiliation: UMR250/9220 ENTROPIE IRD-CNRS-UR, Labex CORAIL, Promenade Roger-Laroque, Noumea cedex, New Caledonia, France
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23
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Dorrell RG, Klinger CM, Newby RJ, Butterfield ER, Richardson E, Dacks JB, Howe CJ, Nisbet ER, Bowler C. Progressive and Biased Divergent Evolution Underpins the Origin and Diversification of Peridinin Dinoflagellate Plastids. Mol Biol Evol 2016; 34:361-379. [DOI: 10.1093/molbev/msw235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Coral community response to bleaching on a highly disturbed reef. Sci Rep 2016; 6:20717. [PMID: 26876092 PMCID: PMC4753424 DOI: 10.1038/srep20717] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 01/06/2016] [Indexed: 11/15/2022] Open
Abstract
While many studies of coral bleaching report on broad, regional scale responses, fewer examine variation in susceptibility among coral taxa and changes in community structure, before, during and after bleaching on individual reefs. Here we report in detail on the response to bleaching by a coral community on a highly disturbed reef site south of mainland Singapore before, during and after a major thermal anomaly in 2010. To estimate the capacity for resistance to thermal stress, we report on: a) overall bleaching severity during and after the event, b) differences in bleaching susceptibility among taxa during the event, and c) changes in coral community structure one year before and after bleaching. Approximately two thirds of colonies bleached, however, post-bleaching recovery was quite rapid and, importantly, coral taxa that are usually highly susceptible were relatively unaffected. Although total coral cover declined, there was no significant change in coral taxonomic community structure before and after bleaching. Several factors may have contributed to the overall high resistance of corals at this site including Symbiodinium affiliation, turbidity and heterotrophy. Our results suggest that, despite experiencing chronic anthropogenic disturbances, turbid shallow reef communities may be remarkably resilient to acute thermal stress.
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25
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Parkinson JE, Baumgarten S, Michell CT, Baums IB, LaJeunesse TC, Voolstra CR. Gene Expression Variation Resolves Species and Individual Strains among Coral-Associated Dinoflagellates within the Genus Symbiodinium. Genome Biol Evol 2016; 8:665-80. [PMID: 26868597 PMCID: PMC4824173 DOI: 10.1093/gbe/evw019] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Reef-building corals depend on symbiotic mutualisms with photosynthetic dinoflagellates in the genus Symbiodinium. This large microalgal group comprises many highly divergent lineages (“Clades A–I”) and hundreds of undescribed species. Given their ecological importance, efforts have turned to genomic approaches to characterize the functional ecology of Symbiodinium. To date, investigators have only compared gene expression between representatives from separate clades—the equivalent of contrasting genera or families in other dinoflagellate groups—making it impossible to distinguish between clade-level and species-level functional differences. Here, we examined the transcriptomes of four species within one Symbiodinium clade (Clade B) at ∼20,000 orthologous genes, as well as multiple isoclonal cell lines within species (i.e., cultured strains). These species span two major adaptive radiations within Clade B, each encompassing both host-specialized and ecologically cryptic taxa. Species-specific expression differences were consistently enriched for photosynthesis-related genes, likely reflecting selection pressures driving niche diversification. Transcriptional variation among strains involved fatty acid metabolism and biosynthesis pathways. Such differences among individuals are potentially a major source of physiological variation, contributing to the functional diversity of coral holobionts composed of unique host–symbiont genotype pairings. Our findings expand the genomic resources available for this important symbiont group and emphasize the power of comparative transcriptomics as a method for studying speciation processes and interindividual variation in nonmodel organisms.
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Affiliation(s)
| | - Sebastian Baumgarten
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Craig T Michell
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | | | | | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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Animal–Symbiodinium Symbioses: Foundations of Coral Reef Ecosystems. ADVANCES IN ENVIRONMENTAL MICROBIOLOGY 2016. [DOI: 10.1007/978-3-319-28068-4_10] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Xiang T, Nelson W, Rodriguez J, Tolleter D, Grossman AR. Symbiodinium transcriptome and global responses of cells to immediate changes in light intensity when grown under autotrophic or mixotrophic conditions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:67-80. [PMID: 25664570 DOI: 10.1111/tpj.12789] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/26/2015] [Accepted: 02/03/2015] [Indexed: 05/10/2023]
Abstract
Symbiosis between unicellular dinoflagellates (genus Symbiodinium) and their cnidarian hosts (e.g. corals, sea anemones) is the foundation of coral reef ecosystems. Dysfunction of this symbiosis under changing environmental conditions has led to global reef decline. Little information is known about Symbiodinium gene expression and mechanisms by which light impacts host-symbiont associations. To address these issues, we generated a transcriptome from axenic Symbiodinium strain SSB01. Here we report features of the transcriptome, including occurrence and length distribution of spliced leader sequences, the functional landscape of encoded proteins and the impact of light on gene expression. Expression of many Symbiodinium genes appears to be significantly impacted by light. Transcript encoding cryptochrome 2 declined in high light while some transcripts for Regulators of Chromatin Condensation (RCC1) declined in the dark. We also identified a transcript encoding a light harvesting AcpPC protein with homology to Chlamydomonas LHCSR2. The level of this transcript increased in high light autotrophic conditions, suggesting that it is involved in photo-protection and the dissipation of excess absorbed light energy. The most extensive changes in transcript abundances occurred when the algae were transferred from low light to darkness. Interestingly, transcripts encoding several cell adhesion proteins rapidly declined following movement of cultures to the dark, which correlated with a dramatic change in cell surface morphology, likely reflecting the complexity of the extracellular matrix. Thus, light-sensitive cell adhesion proteins may play a role in establishing surface architecture, which may in turn alter interactions between the endosymbiont and its host.
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Affiliation(s)
- Tingting Xiang
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, 94305, USA
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28
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Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes. Proc Natl Acad Sci U S A 2015; 112:10177-84. [PMID: 25814499 DOI: 10.1073/pnas.1422049112] [Citation(s) in RCA: 247] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial and plastid genomes show a wide array of architectures, varying immensely in size, structure, and content. Some organelle DNAs have even developed elaborate eccentricities, such as scrambled coding regions, nonstandard genetic codes, and convoluted modes of posttranscriptional modification and editing. Here, we compare and contrast the breadth of genomic complexity between mitochondrial and plastid chromosomes. Both organelle genomes have independently evolved many of the same features and taken on similar genomic embellishments, often within the same species or lineage. This trend is most likely because the nuclear-encoded proteins mediating these processes eventually leak from one organelle into the other, leading to a high likelihood of processes appearing in both compartments in parallel. However, the complexity and intensity of genomic embellishments are consistently more pronounced for mitochondria than for plastids, even when they are found in both compartments. We explore the evolutionary forces responsible for these patterns and argue that organelle DNA repair processes, mutation rates, and population genetic landscapes are all important factors leading to the observed convergence and divergence in organelle genome architecture.
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29
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Pochon X, Forsman ZH, Spalding HL, Padilla-Gamiño JL, Smith CM, Gates RD. Depth specialization in mesophotic corals (Leptoseris spp.) and associated algal symbionts in Hawai'i. ROYAL SOCIETY OPEN SCIENCE 2015; 2:140351. [PMID: 26064599 PMCID: PMC4448807 DOI: 10.1098/rsos.140351] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/07/2015] [Indexed: 05/14/2023]
Abstract
Corals at the lower limits of mesophotic habitats are likely to have unique photosynthetic adaptations that allow them to persist and dominate in these extreme low light ecosystems. We examined the host-symbiont relationships from the dominant coral genus Leptoseris in mesophotic environments from Hawai'i collected by submersibles across a depth gradient of 65-125 m. Coral and Symbiodinium genotypes were compared with three distinct molecular markers including coral (COX1-1-rRNA intron) and Symbiodinium (COI) mitochondrial markers and nuclear ITS2. The phylogenetic reconstruction clearly resolved five Leptoseris species, including one species (Leptoseris hawaiiensis) exclusively found in deeper habitats (115-125 m). The Symbiodinium mitochondrial marker resolved three unambiguous haplotypes in clade C, which were found at significantly different frequencies between host species and depths, with one haplotype exclusively found at the lower mesophotic extremes (95-125 m). These patterns of host-symbiont depth specialization indicate that there are limits to connectivity between upper and lower mesophotic zones, suggesting that niche specialization plays a critical role in host-symbiont evolution at mesophotic extremes.
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Affiliation(s)
- X. Pochon
- Environmental Technologies, Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
- Institute of Marine Science, University of Auckland, Auckland, New Zealand
- Author for correspondence: X. Pochon e-mail:
| | - Z. H. Forsman
- Hawai'i Institute of Marine Biology, University of Hawai'i, Kaneohe, HI, USA
| | - H. L. Spalding
- Department of Botany, University of Hawai'i at Mnoa, Honolulu, HI, USA
| | - J. L. Padilla-Gamiño
- Department of Biology, California State University Dominguez Hills, Carson, CA, USA
| | - C. M. Smith
- Department of Botany, University of Hawai'i at Mnoa, Honolulu, HI, USA
| | - R. D. Gates
- Hawai'i Institute of Marine Biology, University of Hawai'i, Kaneohe, HI, USA
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30
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Schelkunov MI, Shtratnikova VY, Nuraliev MS, Selosse MA, Penin AA, Logacheva MD. Exploring the limits for reduction of plastid genomes: a case study of the mycoheterotrophic orchids Epipogium aphyllum and Epipogium roseum. Genome Biol Evol 2015; 7:1179-91. [PMID: 25635040 PMCID: PMC4419786 DOI: 10.1093/gbe/evv019] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The question on the patterns and limits of reduction of plastid genomes in nonphotosynthetic plants and the reasons of their conservation is one of the intriguing topics in plant genome evolution. Here, we report sequencing and analysis of plastid genome in nonphotosynthetic orchids Epipogium aphyllum and Epipogium roseum, which, with sizes of 31 and 19 kbp, respectively, represent the smallest plastid genomes characterized by now. Besides drastic reduction, which is expected, we found several unusual features of these “minimal” plastomes: Multiple rearrangements, highly biased nucleotide composition, and unprecedentedly high substitution rate. Only 27 and 29 genes remained intact in the plastomes of E. aphyllum and E. roseum—those encoding ribosomal components, transfer RNAs, and three additional housekeeping genes (infA, clpP, and accD). We found no signs of relaxed selection acting on these genes. We hypothesize that the main reason for retention of plastid genomes in Epipogium is the necessity to translate messenger RNAs (mRNAs) of accD and/or clpP proteins which are essential for cell metabolism. However, these genes are absent in plastomes of several plant species; their absence is compensated by the presence of a functional copy arisen by gene transfer from plastid to the nuclear genome. This suggests that there is no single set of plastid-encoded essential genes, but rather different sets for different species and that the retention of a gene in the plastome depends on the interaction between the nucleus and plastids.
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Affiliation(s)
| | | | - Maxim S Nuraliev
- M. V. Lomonosov Moscow State University, Moscow, Russia Joint Russian-Vietnamese Tropical Scientific and Technological Center, Cau Giay, Hanoi, Vietnam
| | - Marc-Andre Selosse
- Département Systématique et Evolution, Muséum National d'Histoire Naturelle, Paris, France
| | | | - Maria D Logacheva
- M. V. Lomonosov Moscow State University, Moscow, Russia Kazan Federal University, Kazan, Russia
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31
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Arif C, Daniels C, Bayer T, Banguera-Hinestroza E, Barbrook A, Howe CJ, LaJeunesse TC, Voolstra CR. Assessing Symbiodinium diversity in scleractinian corals via next-generation sequencing-based genotyping of the ITS2 rDNA region. Mol Ecol 2014; 23:4418-33. [PMID: 25052021 PMCID: PMC4285332 DOI: 10.1111/mec.12869] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/17/2014] [Accepted: 07/18/2014] [Indexed: 01/24/2023]
Abstract
The persistence of coral reef ecosystems relies on the symbiotic relationship between scleractinian corals and intracellular, photosynthetic dinoflagellates in the genus Symbiodinium. Genetic evidence indicates that these symbionts are biologically diverse and exhibit discrete patterns of environmental and host distribution. This makes the assessment of Symbiodinium diversity critical to understanding the symbiosis ecology of corals. Here, we applied pyrosequencing to the elucidation of Symbiodinium diversity via analysis of the internal transcribed spacer 2 (ITS2) region, a multicopy genetic marker commonly used to analyse Symbiodinium diversity. Replicated data generated from isoclonal Symbiodinium cultures showed that all genomes contained numerous, yet mostly rare, ITS2 sequence variants. Pyrosequencing data were consistent with more traditional denaturing gradient gel electrophoresis (DGGE) approaches to the screening of ITS2 PCR amplifications, where the most common sequences appeared as the most intense bands. Further, we developed an operational taxonomic unit (OTU)-based pipeline for Symbiodinium ITS2 diversity typing to provisionally resolve ecologically discrete entities from intragenomic variation. A genetic distance cut-off of 0.03 collapsed intragenomic ITS2 variants of isoclonal cultures into single OTUs. When applied to the analysis of field-collected coral samples, our analyses confirm that much of the commonly observed SymbiodiniumITS2 diversity can be attributed to intragenomic variation. We conclude that by analysing Symbiodinium populations in an OTU-based framework, we can improve objectivity, comparability and simplicity when assessing ITS2 diversity in field-based studies.
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Affiliation(s)
- Chatchanit Arif
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), 23955, Thuwal, Saudi Arabia
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32
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Pochon X, Putnam HM, Gates RD. Multi-gene analysis of Symbiodinium dinoflagellates: a perspective on rarity, symbiosis, and evolution. PeerJ 2014; 2:e394. [PMID: 24883254 PMCID: PMC4034598 DOI: 10.7717/peerj.394] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/03/2014] [Indexed: 11/20/2022] Open
Abstract
Symbiodinium, a large group of dinoflagellates, live in symbiosis with marine protists, invertebrate metazoans, and free-living in the environment. Symbiodinium are functionally variable and play critical energetic roles in symbiosis. Our knowledge of Symbiodinium has been historically constrained by the limited number of molecular markers available to study evolution in the genus. Here we compare six functional genes, representing three cellular compartments, in the nine known Symbiodinium lineages. Despite striking similarities among the single gene phylogenies from distinct organelles, none were evolutionarily identical. A fully concatenated reconstruction, however, yielded a well-resolved topology identical to the current benchmark nr28S gene. Evolutionary rates differed among cellular compartments and clades, a pattern largely driven by higher rates of evolution in the chloroplast genes of Symbiodinium clades D2 and I. The rapid rates of evolution observed amongst these relatively uncommon Symbiodinium lineages in the functionally critical chloroplast may translate into potential innovation for the symbiosis. The multi-gene analysis highlights the potential power of assessing genome-wide evolutionary patterns using recent advances in sequencing technology and emphasizes the importance of integrating ecological data with more comprehensive sampling of free-living and symbiotic Symbiodinium in assessing the evolutionary adaptation of this enigmatic dinoflagellate.
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Affiliation(s)
- Xavier Pochon
- Environmental Technologies, Cawthron Institute , Nelson , New Zealand
| | - Hollie M Putnam
- University of Hawaii, Hawaii Institute of Marine Biology , Kaneohe, HI , USA
| | - Ruth D Gates
- University of Hawaii, Hawaii Institute of Marine Biology , Kaneohe, HI , USA
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