1
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Wang H, Wu P, Xiong L, Kim HS, Kim JH, Ki JS. Nuclear genome of dinoflagellates: Size variation and insights into evolutionary mechanisms. Eur J Protistol 2024; 93:126061. [PMID: 38394997 DOI: 10.1016/j.ejop.2024.126061] [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: 10/24/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024]
Abstract
Recent progress in high-throughput sequencing technologies has dramatically increased availability of genome data for prokaryotes and eukaryotes. Dinoflagellates have distinct chromosomes and a huge genome size, which make their genomic analysis complicated. Here, we reviewed the nuclear genomes of core dinoflagellates, focusing on the genome and cell size. Till now, the genome sizes of several dinoflagellates (more than 25) have been measured by certain methods (e.g., flow cytometry), showing a range of 3-250 pg of genomic DNA per cell. In contrast to their relatively small cell size, their genomes are huge (about 1-80 times the human haploid genome). In the present study, we collected the genome and cell size data of dinoflagellates and compared their relationships. We found that dinoflagellate genome size exhibits a positive correlation with cell size. On the other hand, we recognized that the genome size is not correlated with phylogenetic relatedness. These may be caused by genome duplication, increased gene copy number, repetitive non-coding DNA, transposon expansion, horizontal gene transfer, organelle-to-nucleus gene transfer, and/or mRNA reintegration into the genome. Ultimate verification of these factors as potential causative mechanisms would require sequencing of more dinoflagellate genomes in the future.
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Affiliation(s)
- Hui Wang
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China; Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea
| | - Peiling Wu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Lu Xiong
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, China
| | - Han-Sol Kim
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea
| | - Jin Ho Kim
- Department of Earth and Marine Science, College of Ocean Sciences, Jeju National University, Jeju 63243, Republic of Korea
| | - Jang-Seu Ki
- Department of Life Science, Sangmyung University, Seoul 03016, Republic of Korea; Department of Biotechnology, Sangmyung University, Seoul 03016, Republic of Korea.
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2
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Benites LF, Stephens TG, Bhattacharya D. Multiple waves of viral invasions in Symbiodiniaceae algal genomes. Virus Evol 2022; 8:veac101. [PMID: 36381231 PMCID: PMC9651163 DOI: 10.1093/ve/veac101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 08/29/2022] [Accepted: 10/25/2022] [Indexed: 08/13/2023] Open
Abstract
Dinoflagellates from the family Symbiodiniaceae are phototrophic marine protists that engage in symbiosis with diverse hosts. Their large and distinct genomes are characterized by pervasive gene duplication and large-scale retroposition events. However, little is known about the role and scale of horizontal gene transfer (HGT) in the evolution of this algal family. In other dinoflagellates, high levels of HGTs have been observed, linked to major genomic transitions, such as the appearance of a viral-acquired nucleoprotein that originated via HGT from a large DNA algal virus. Previous work showed that Symbiodiniaceae from different hosts are actively infected by viral groups, such as giant DNA viruses and ssRNA viruses, that may play an important role in coral health. Latent viral infections may also occur, whereby viruses could persist in the cytoplasm or integrate into the host genome as a provirus. This hypothesis received experimental support; however, the cellular localization of putative latent viruses and their taxonomic affiliation are still unknown. In addition, despite the finding of viral sequences in some genomes of Symbiodiniaceae, viral origin, taxonomic breadth, and metabolic potential have not been explored. To address these questions, we searched for putative viral-derived proteins in thirteen Symbiodiniaceae genomes. We found fifty-nine candidate viral-derived HGTs that gave rise to twelve phylogenies across ten genomes. We also describe the taxonomic affiliation of these virus-related sequences, their structure, and their genomic context. These results lead us to propose a model to explain the origin and fate of Symbiodiniaceae viral acquisitions.
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Affiliation(s)
- L Felipe Benites
- Department of Biochemistry and Microbiology, Rutgers University, 102 Foran Hall, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA
| | - Timothy G Stephens
- Department of Biochemistry and Microbiology, Rutgers University, 102 Foran Hall, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, 102 Foran Hall, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA
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3
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McParland EL, Lee MD, Webb EA, Alexander H, Levine NM. DMSP synthesis genes distinguish two types of DMSP producer phenotypes. Environ Microbiol 2021; 23:1656-1669. [PMID: 33415763 DOI: 10.1111/1462-2920.15393] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/10/2020] [Accepted: 01/04/2021] [Indexed: 11/25/2022]
Abstract
Dimethylsulfoniopropionate (DMSP) is an important organic carbon and sulfur source in the surface ocean that fuels microbial activity and significantly impacts Earth's climate. After three decades of research, the cellular role(s) of DMSP and environmental drivers of production remain enigmatic. Recent work suggests that cellular DMSP concentrations, and changes in these concentrations in response to environmental stressors, define two major groups of DMSP producers: high DMSP producers that contain ≥ 50 mM intracellular DMSP and low DMSP producers that contain < 50 mM. Here we show that two recently described DMSP synthesis genes (DSYB and TpMT2) may differentiate these two DMSP phenotypes. A survey of prokaryotic and eukaryotic isolates found a significant correlation between the presence of DSYB and TpMT2 genes and previous measurements of high and low DMSP concentrations, respectively. Phylogenetic analysis demonstrated that DSYB and TpMT2 form two distinct clades. DSYB and TpMT2 were also found to be globally abundant in in situ surface communities, and their taxonomic annotations were similar to those observed for isolates. The strong correlation of the DSYB and TpMT2 synthesis genes with high and low producer phenotypes establishes a foundation for direct quantification of DMSP producers, enabling significantly improved predictions of DMSP in situ.
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Affiliation(s)
- Erin L McParland
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA.,Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Michael D Lee
- Exobiology Branch, NASA Ames Research Center, Mountain View, California, USA.,Blue Marble Space Institute of Science, Seattle, Washington, USA
| | - Eric A Webb
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Harriet Alexander
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Naomi M Levine
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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4
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Sprecher BN, Zhang H, Lin S. Nuclear Gene Transformation in the Dinoflagellate Oxyrrhis marina. Microorganisms 2020; 8:E126. [PMID: 31963386 PMCID: PMC7022241 DOI: 10.3390/microorganisms8010126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 11/16/2022] Open
Abstract
The lack of a robust gene transformation tool that allows proper expression of foreign genes and functional testing for the vast number of nuclear genes in dinoflagellates has greatly hampered our understanding of the fundamental biology in this ecologically important and evolutionarily unique lineage of microeukaryotes. Here, we report the development of a dinoflagellate expression vector containing various DNA elements from phylogenetically separate dinoflagellate lineages, an electroporation protocol, and successful expression of introduced genes in an early branching dinoflagellate, Oxyrrhis marina. This protocol, involving the use of Lonza's Nucleofector and a codon-optimized antibiotic resistance gene, has been successfully used to produce consistent results in several independent experiments for O. marina. It is anticipated that this protocol will be adaptable for other dinoflagellates and will allow characterization of many novel dinoflagellate genes.
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Affiliation(s)
| | - Huan Zhang
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd, Groton, CT 06340, USA;
| | - Senjie Lin
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd, Groton, CT 06340, USA;
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5
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Fugacium Spliced Leader Genes Identified from Stranded RNA-Seq Datasets. Microorganisms 2019; 7:microorganisms7060171. [PMID: 31212635 PMCID: PMC6616646 DOI: 10.3390/microorganisms7060171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 05/27/2019] [Accepted: 06/05/2019] [Indexed: 01/10/2023] Open
Abstract
Trans-splicing mechanisms have been documented in many lineages that are widely distributed phylogenetically, including dinoflagellates. The spliced leader (SL) sequence itself is conserved in dinoflagellates, although its gene sequences and arrangements have diversified within or across different species. In this study, we present 18 Fugacium kawagutii SL genes identified from stranded RNA-seq reads. These genes typically have a single SL but can contain several partial SLs with lengths ranging from 103 to 292 bp. Unexpectedly, we find the SL gene transcripts contain sequences upstream of the canonical SL, suggesting that generation of mature transcripts will require additional modifications following trans-splicing. We have also identified 13 SL-like genes whose expression levels and length are comparable to Dino-SL genes. Lastly, introns in these genes were identified and a new site for Sm-protein binding was proposed. Overall, this study provides a strategy for fast identification of SL genes and identifies new sequences of F. kawagutii SL genes to supplement our understanding of trans-splicing.
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6
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Beedessee G, Hisata K, Roy MC, Van Dolah FM, Satoh N, Shoguchi E. Diversified secondary metabolite biosynthesis gene repertoire revealed in symbiotic dinoflagellates. Sci Rep 2019; 9:1204. [PMID: 30718591 PMCID: PMC6361889 DOI: 10.1038/s41598-018-37792-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 12/13/2018] [Indexed: 11/09/2022] Open
Abstract
Symbiodiniaceae dinoflagellates possess smaller nuclear genomes than other dinoflagellates and produce structurally specialized, biologically active, secondary metabolites. Till date, little is known about the evolution of secondary metabolism in dinoflagellates as comparative genomic approaches have been hampered by their large genome sizes. Here, we overcome this challenge by combining genomic and metabolomics approaches to investigate how chemical diversity arises in three decoded Symbiodiniaceae genomes (clades A3, B1 and C). Our analyses identify extensive diversification of polyketide synthase and non-ribosomal peptide synthetase genes from two newly decoded genomes of Symbiodinium tridacnidorum (A3) and Cladocopium sp. (C). Phylogenetic analyses indicate that almost all the gene families are derived from lineage-specific gene duplications in all three clades, suggesting divergence for environmental adaptation. Few metabolic pathways are conserved among the three clades and we detect metabolic similarity only in the recently diverged clades, B1 and C. We establish that secondary metabolism protein architecture guides substrate specificity and that gene duplication and domain shuffling have resulted in diversification of secondary metabolism genes.
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Affiliation(s)
- Girish Beedessee
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan.
| | - Kanako Hisata
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Michael C Roy
- Instrumental Analysis Section, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Frances M Van Dolah
- College of Charleston, School of Sciences and Mathematics, 66 George St., Charleston, South Carolina, 29424, USA
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan
| | - Eiichi Shoguchi
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, 904-0495, Japan.
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7
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Riaz S, Sui Z, Niaz Z, Khan S, Liu Y, Liu H. Distinctive Nuclear Features of Dinoflagellates with A Particular Focus on Histone and Histone-Replacement Proteins. Microorganisms 2018; 6:E128. [PMID: 30558155 PMCID: PMC6313786 DOI: 10.3390/microorganisms6040128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/29/2018] [Accepted: 12/11/2018] [Indexed: 11/30/2022] Open
Abstract
Dinoflagellates are important eukaryotic microorganisms that play critical roles as producers and grazers, and cause harmful algal blooms. The unusual nuclei of dinoflagellates "dinokaryon" have led researchers to investigate their enigmatic nuclear features. Their nuclei are unusual in terms of their permanently condensed nucleosome-less chromatin, immense genome, low protein to DNA ratio, guanine-cytosine rich methylated DNA, and unique mitosis process. Furthermore, dinoflagellates are the only known group of eukaryotes that apparently lack histone proteins. Over the course of evolution, dinoflagellates have recruited other proteins, e.g., histone-like proteins (HLPs), from bacteria and dinoflagellates/viral nucleoproteins (DVNPs) from viruses as histone substitutes. Expression diversity of these nucleoproteins has greatly influenced the chromatin structure and gene expression regulation in dinoflagellates. Histone replacement proteins (HLPs and DVNPs) are hypothesized to perform a few similar roles as histone proteins do in other eukaryotes, i.e., gene expression regulation and repairing DNA. However, their role in bulk packaging of DNA is not significant as low amounts of proteins are associated with the gigantic genome. This review intends to summarize the discoveries encompassing unique nuclear features of dinoflagellates, particularly focusing on histone and histone replacement proteins. In addition, a comprehensive view of the evolution of dinoflagellate nuclei is presented.
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Affiliation(s)
- Sadaf Riaz
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
- Department of Microbiology, University of Veterinary and Animal Sciences, Lahore 54000, Pakistan.
| | - Zhenghong Sui
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
| | - Zeeshan Niaz
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
- Department of Microbiology, Hazara University, Mansehra 21120, Pakistan.
| | - Sohrab Khan
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
- Department of Microbiology, Hazara University, Mansehra 21120, Pakistan.
| | - Yuan Liu
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
| | - Haoxin Liu
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao, 266003, China.
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8
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Song B, Chen S, Chen W. Dinoflagellates, a Unique Lineage for Retrogene Research. Front Microbiol 2018; 9:1556. [PMID: 30050525 PMCID: PMC6050394 DOI: 10.3389/fmicb.2018.01556] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/22/2018] [Indexed: 12/14/2022] Open
Abstract
The birth and evolution of retrogenes have played crucial roles in genome evolution. Dinoflagellates represent a unique lineage for retrogene research because the retrogenes can be reliably identified by the presence of a 22 nucleotide splice leader called DinoSL, which is post-transcriptionally added to the 5' terminus of all mRNAs. Compared to studies of retrogenes conducted in other model genomes, dinoflagellate retrogenes can potentially be more comprehensively characterized because intron-containing retrogenes have already been detected. Unfortunately, dinoflagellate retrogene research has long been neglected. Here, we review the work on dinoflagellate retrogenes and show their distinct character. Like the dinoflagellate genome itself, dinoflagellate retrogenes are also characterized by many unusual features, including a high survival rate and large numbers in the genome. These data are critical complements to what we know about retrogenes, and will further frame our understanding of retroposition and its roles in genome evolution, as well as providing new insights into retrogene studies in other genomes.
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Affiliation(s)
- Bo Song
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Sijie Chen
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Wenbin Chen
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
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9
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Song B, Morse D, Song Y, Fu Y, Lin X, Wang W, Cheng S, Chen W, Liu X, Lin S. Comparative Genomics Reveals Two Major Bouts of Gene Retroposition Coinciding with Crucial Periods of Symbiodinium Evolution. Genome Biol Evol 2018; 9:2037-2047. [PMID: 28903461 PMCID: PMC5585692 DOI: 10.1093/gbe/evx144] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2017] [Indexed: 12/21/2022] Open
Abstract
Gene retroposition is an important mechanism of genome evolution but the role it plays in dinoflagellates, a critical player in marine ecosystems, is not known. Until recently, when the genomes of two coral-symbiotic dinoflagellate genomes, Symbiodinium kawagutii and S. minutum, were released, it has not been possible to systematically study these retrogenes. Here we examine the abundant retrogenes (∼23% of the total genes) in these species. The hallmark of retrogenes in the genome is the presence of DCCGTAGCCATTTTGGCTCAAG, a spliced leader (DinoSL) constitutively trans-spliced to the 5′-end of all nucleus-encoded mRNAs. Although the retrogenes have often lost part of the 22-nt DinoSL, the putative promoter motif from the DinoSL, TTT(T/G), is consistently retained in the upstream region of these genes, providing an explanation for the high survival rate of retrogenes in dinoflagellates. Our analysis of DinoSL sequence divergence revealed two major bursts of retroposition in the evolutionary history of Symbiodinium, occurring at ∼60 and ∼6 Ma. Reconstruction of the evolutionary trajectory of the Symbiodinium genomes mapped these 2 times to the origin and rapid radiation of this dinoflagellate lineage, respectively. GO analysis revealed differential functional enrichment of the retrogenes between the two episodes, with a broad impact on transport in the first bout and more localized influence on symbiosis-related processes such as cell adhesion in the second bout. This study provides the first evidence of large-scale retroposition as a major mechanism of genome evolution for any organism and sheds light on evolution of coral symbiosis.
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Affiliation(s)
- Bo Song
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China.,BGI-Shenzhen, Shenzhen, China
| | - David Morse
- Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Canada
| | - Yue Song
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Yuan Fu
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Xin Lin
- State Key Laboratory of Marine Environmental Science and Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, China
| | - Wenliang Wang
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Shifeng Cheng
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Wenbin Chen
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Xin Liu
- BGI-Shenzhen, Shenzhen, China.,China National GeneBank, BGI-Shenzhen, Shenzhen, China
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science and Marine Biodiversity and Global Change Research Center, Xiamen University, Xiamen, China.,Department of Marine Sciences, University of Connecticut, Groton
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10
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Meng A, Corre E, Probert I, Gutierrez-Rodriguez A, Siano R, Annamale A, Alberti A, Da Silva C, Wincker P, Le Crom S, Not F, Bittner L. Analysis of the genomic basis of functional diversity in dinoflagellates using a transcriptome-based sequence similarity network. Mol Ecol 2018; 27:2365-2380. [PMID: 29624751 DOI: 10.1111/mec.14579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 02/23/2018] [Accepted: 03/21/2018] [Indexed: 02/06/2023]
Abstract
Dinoflagellates are one of the most abundant and functionally diverse groups of eukaryotes. Despite an overall scarcity of genomic information for dinoflagellates, constantly emerging high-throughput sequencing resources can be used to characterize and compare these organisms. We assembled de novo and processed 46 dinoflagellate transcriptomes and used a sequence similarity network (SSN) to compare the underlying genomic basis of functional features within the group. This approach constitutes the most comprehensive picture to date of the genomic potential of dinoflagellates. A core-predicted proteome composed of 252 connected components (CCs) of putative conserved protein domains (pCDs) was identified. Of these, 206 were novel and 16 lacked any functional annotation in public databases. Integration of functional information in our network analyses allowed investigation of pCDs specifically associated with functional traits. With respect to toxicity, sequences homologous to those of proteins found in species with toxicity potential (e.g., sxtA4 and sxtG) were not specific to known toxin-producing species. Although not fully specific to symbiosis, the most represented functions associated with proteins involved in the symbiotic trait were related to membrane processes and ion transport. Overall, our SSN approach led to identification of 45,207 and 90,794 specific and constitutive pCDs of, respectively, the toxic and symbiotic species represented in our analyses. Of these, 56% and 57%, respectively (i.e., 25,393 and 52,193 pCDs), completely lacked annotation in public databases. This stresses the extent of our lack of knowledge, while emphasizing the potential of SSNs to identify candidate pCDs for further functional genomic characterization.
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Affiliation(s)
- Arnaud Meng
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles Guyane, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), Paris, France
| | - Erwan Corre
- CNRS, UPMC, FR2424, ABiMS, Station Biologique, Roscoff, France
| | - Ian Probert
- UPMC-CNRS, FR2424, Roscoff Culture Collection, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| | | | - Raffaele Siano
- Ifremer - Centre de Brest, DYNECO PELAGOS, Plouzané, France
| | - Anita Annamale
- CEA - Institut de Génomique, GENOSCOPE, Evry, France.,CNRS, UMR8030, Evry, France.,Université d'Evry Val d'Essonne, Evry, France
| | - Adriana Alberti
- CEA - Institut de Génomique, GENOSCOPE, Evry, France.,CNRS, UMR8030, Evry, France.,Université d'Evry Val d'Essonne, Evry, France
| | - Corinne Da Silva
- CEA - Institut de Génomique, GENOSCOPE, Evry, France.,CNRS, UMR8030, Evry, France.,Université d'Evry Val d'Essonne, Evry, France
| | - Patrick Wincker
- CEA - Institut de Génomique, GENOSCOPE, Evry, France.,CNRS, UMR8030, Evry, France.,Université d'Evry Val d'Essonne, Evry, France
| | - Stéphane Le Crom
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles Guyane, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), Paris, France
| | - Fabrice Not
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| | - Lucie Bittner
- Sorbonne Universités, UPMC Univ Paris 06, Univ Antilles Guyane, Univ Nice Sophia Antipolis, CNRS, Evolution Paris Seine - Institut de Biologie Paris Seine (EPS - IBPS), Paris, France
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11
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Shi X, Ma M, Lin S. Cell Cycle-Dependent Expression Dynamics of G1/S Specific Cyclin, Cellulose Synthase and Cellulase in the Dinoflagellate Prorocentrum donghaiense. Front Microbiol 2017; 8:1118. [PMID: 28676796 PMCID: PMC5476699 DOI: 10.3389/fmicb.2017.01118] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 06/01/2017] [Indexed: 01/02/2023] Open
Abstract
Dinoflagellates undergo a typical eukaryotic cell cycle consisting of G1, S, G2, and M phases and some of the typical cell cycle related genes have been computationally identified. However, very few of these genes have been experimentally linked to the cell cycle phases. Besides, although thecate dinoflagellates are known to possess theca composed of cellulose, information on cellulose synthesis and degradation associated with the cell cycle is also limited. In this study, we isolated G1/S cyclin, cellulose synthase and cellulase encoding genes in dinoflagellate Prorocentrum donghaiense. Further, using reverse transcription quantitative PCR (RT-qPCR), we characterized the expression profiles of the three genes throughout the cell cycle. All three showed clear expression dynamics throughout the cell cycle, with fold changes of 26, 2.4 and 9.3 for G1/S cyclin, cellulose synthase and cellulase gene, respectively. The transcript abundance of G1/S cyclin increased in late G1 phase and dropped in early S phase, indicating that this protein is involved in the G1/S transition. Throughout the cell cycle, the average transcript level of cellulose synthase was 4.5-fold higher than that of cellulase. Cellulose synthase and cellulase gene expressions showed peak transcript abundances at middle G1 phase and G2M phase, respectively, indicating the respective roles of these enzymes in the growth of newly divided cells and in cytokinesis. Our results suggest that G1/S cyclin, cellulase, and cellulose synthase genes associated with G1/S transition, G2M, and G1 phases of the cell cycle and are candidates of biomarkers for assessing growth status of P. donghaiense.
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Affiliation(s)
- Xinguo Shi
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen UniversityXiamen, China
| | - Minglei Ma
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen UniversityXiamen, China
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen UniversityXiamen, China.,Department of Marine Sciences, University of Connecticut, GrotonCT, United States
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Caron DA, Alexander H, Allen AE, Archibald JM, Armbrust EV, Bachy C, Bell CJ, Bharti A, Dyhrman ST, Guida SM, Heidelberg KB, Kaye JZ, Metzner J, Smith SR, Worden AZ. Probing the evolution, ecology and physiology of marine protists using transcriptomics. Nat Rev Microbiol 2016; 15:6-20. [DOI: 10.1038/nrmicro.2016.160] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Hehenberger E, Imanian B, Burki F, Keeling PJ. Evidence for the retention of two evolutionary distinct plastids in dinoflagellates with diatom endosymbionts. Genome Biol Evol 2015; 6:2321-34. [PMID: 25172904 PMCID: PMC4217693 DOI: 10.1093/gbe/evu182] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Dinoflagellates harboring diatom endosymbionts (termed “dinotoms”) have undergone a process often referred to as “tertiary endosymbiosis”—the uptake of algae containing secondary plastids and integration of those plastids into the new host. In contrast to other tertiary plastids, and most secondary plastids, the endosymbiont of dinotoms is distinctly less reduced, retaining a number of cellular features, such as their nucleus and mitochondria and others, in addition to their plastid. This has resulted in redundancy between host and endosymbiont, at least between some mitochondrial and cytosolic metabolism, where this has been investigated. The question of plastidial redundancy is particularly interesting as the fate of the host dinoflagellate plastid is unclear. The host cytosol possesses an eyespot that has been postulated to be a remnant of the ancestral peridinin plastid, but this has not been tested, nor has its possible retention of plastid functions. To investigate this possibility, we searched for plastid-associated pathways and functions in transcriptomic data sets from three dinotom species. We show that the dinoflagellate host has indeed retained genes for plastid-associated pathways and that these genes encode targeting peptides similar to those of other dinoflagellate plastid-targeted proteins. Moreover, we also identified one gene encoding an essential component of the dinoflagellate plastid protein import machinery, altogether suggesting the presence of a functioning plastid import system in the host, and by extension a relict plastid. The presence of the same plastid-associated pathways in the endosymbiont also extends the known functional redundancy in dinotoms, further confirming the unusual state of plastid integration in this group of dinoflagellates.
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Affiliation(s)
- Elisabeth Hehenberger
- Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Behzad Imanian
- Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fabien Burki
- Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrick J Keeling
- Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, Canada
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Stüken A, Riobó P, Franco J, Jakobsen KS, Guillou L, Figueroa RI. Paralytic shellfish toxin content is related to genomic sxtA4 copy number in Alexandrium minutum strains. Front Microbiol 2015; 6:404. [PMID: 25983733 PMCID: PMC4416454 DOI: 10.3389/fmicb.2015.00404] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 04/17/2015] [Indexed: 11/27/2022] Open
Abstract
Dinoflagellates are microscopic aquatic eukaryotes with huge genomes and an unusual cell regulation. For example, most genes are present in numerous copies and all copies seem to be obligatorily transcribed. The consequence of the gene copy number (CPN) for final protein synthesis is, however, not clear. One such gene is sxtA, the starting gene of paralytic shellfish toxin (PST) synthesis. PSTs are small neurotoxic compounds that can accumulate in the food chain and cause serious poisoning incidences when ingested. They are produced by dinoflagellates of the genera Alexandrium, Gymnodium, and Pyrodinium. Here we investigated if the genomic CPN of sxtA4 is related to PST content in Alexandrium minutum cells. SxtA4 is the 4th domain of the sxtA gene and its presence is essential for PST synthesis in dinoflagellates. We used PST and genome size measurements as well as quantitative PCR to analyze sxtA4 CPN and toxin content in 15 A. minutum strains. Our results show a strong positive correlation between the sxtA4 CPN and the total amount of PST produced in actively growing A. minutum cells. This correlation was independent of the toxin profile produced, as long as the strain contained the genomic domains sxtA1 and sxtA4.
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Affiliation(s)
- Anke Stüken
- Department of Biosciences, University of Oslo Oslo, Norway
| | - Pilar Riobó
- U.A. Microalgas Nocivas (Consejo Superior de Investigaciones Científicas - Instituto Español de Oceanografía), Instituto de Investigaciones Marinas Vigo, Spain
| | - José Franco
- U.A. Microalgas Nocivas (Consejo Superior de Investigaciones Científicas - Instituto Español de Oceanografía), Instituto de Investigaciones Marinas Vigo, Spain
| | - Kjetill S Jakobsen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo Oslo, Norway
| | - Laure Guillou
- Laboratoire Adaptation et Diversité en Milieu Marin, CNRS, UMR 7144 Roscoff, France ; Sorbonne Universités - Université Pierre et Marie Curie, UMR 7144 Roscoff, France
| | - Rosa I Figueroa
- Aquatic Ecology, Lund University Lund, Sweden ; U.A. Microalgas Nocivas (Consejo Superior de Investigaciones Científicas - Instituto Español de Oceanografía), Instituto Español de Oceanografía Vigo, Spain
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Diversification of the light-harvesting complex gene family via intra- and intergenic duplications in the coral symbiotic alga Symbiodinium. PLoS One 2015; 10:e0119406. [PMID: 25741697 PMCID: PMC4351107 DOI: 10.1371/journal.pone.0119406] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/12/2015] [Indexed: 12/22/2022] Open
Abstract
The light-harvesting complex (LHC) is an essential component in light energy capture and transduction to facilitate downstream photosynthetic reactions in plant and algal chloroplasts. The unicellular dinoflagellate alga Symbiodinium is an endosymbiont of cnidarian animals, including corals and sea anemones, and provides carbohydrates generated through photosynthesis to host animals. Although Symbiodinium possesses a unique LHC gene family, called chlorophyll a-chlorophyll c2-peridinin protein complex (acpPC), its genome-level diversity and evolutionary trajectories have not been investigated. Here, we describe a phylogenetic analysis revealing that many of the LHCs are encoded by highly duplicated genes with multi-subunit polyprotein structures in the nuclear genome of Symbiodinium minutum. This analysis provides an extended list of the LHC gene family in a single organism, including 80 loci encoding polyproteins composed of 145 LHC subunits recovered in the phylogenetic tree. In S. minutum, 5 phylogenetic groups of the Lhcf-type gene family, which is exclusively conserved in algae harboring secondary plastids of red algal origin, were identified. Moreover, 5 groups of the Lhcr-type gene family, of which members are known to be associated with PSI in red algal plastids and secondary plastids of red algal origin, were identified. Notably, members classified within a phylogenetic group of the Lhcf-type (group F1) are highly duplicated, which may explain the presence of an unusually large number of LHC genes in this species. Some gene units were homologous to other units within single loci of the polyprotein genes, whereas intergenic homologies between separate loci were conspicuous in other cases, implying that gene unit ‘shuffling’ by gene conversion and/or genome rearrangement might have been a driving force for diversification. These results suggest that vigorous intra- and intergenic gene duplication events have resulted in the genomic framework of photosynthesis in coral symbiont dinoflagellate algae.
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