1
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Howe CJ, Barbrook AC. Dinoflagellate chloroplasts as a model for extreme genome reduction and fragmentation in organelles - The COCOA principle for gene retention. Protist 2024; 175:126048. [PMID: 38981407 DOI: 10.1016/j.protis.2024.126048] [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: 05/01/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 07/11/2024]
Abstract
The genomes of peridinin-containing dinoflagellate chloroplasts have a very unusual organisation. These genomes are highly fragmented and greatly reduced, with most of the usual complement of chloroplast genes relocated to the nucleus. Dinoflagellate chloroplasts highlight evolutionary changes that are found to varying extents in a number of other organelle genomes. These include the chloroplast genome of the green alga Boodlea and other Cladophorales, and the mitochondrial genomes of blood-sucking and chewing lice, the parasitic plant Rhopalocnemis phalloides, the red alga Rhodosorus marinus and other members of the Stylonematophyceae, diplonemid flagellates, and some Cnidaria. Consideration of the coding content of the remnant chloroplast genomes indicates that organelles may preferentially retain genes for proteins important in initiating assembly of complexes, and the same is largely true for mitochondria. We propose a new principle, of CO-location for COntrol of Assembly (COCOA), indicating the importance of retaining these genes in the organelle. This adds to, but does not invalidate, the existing hypotheses of the multisubunit completion principle, CO-location for Redox Regulation (CORR) and Control by Epistasy of Synthesis (CES).
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Affiliation(s)
- Christopher J Howe
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK; Stellenbosch Institute for Advanced Study, (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch 7600, South Africa.
| | - Adrian C Barbrook
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge CB2 1QW, UK.
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2
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Guo H, Wang X, Li C, Mohamed HF, Li D, Wang L, Chen H, Lin K, Huang S, Pang J, Zhang Y, Krock B, Luo Z. Ignited competition: Impact of bioactive extracellular compounds on organelle functions and photosynthetic systems in harmful algal blooms. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39047015 DOI: 10.1111/pce.15057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 06/14/2024] [Accepted: 07/15/2024] [Indexed: 07/27/2024]
Abstract
Prevalent interactions among marine phytoplankton triggered by long-range climatic stressors are well-known environmental disturbers of community structure. Dynamic response of phytoplankton physiology is likely to come from interspecies interactions rather than direct climatic effect on single species. However, studies on enigmatic interactions among interspecies, which are induced by bioactive extracellular compounds (BECs), especially between related harmful algae sharing similar shellfish toxins, are scarce. Here, we investigated how BECs provoke the interactions between two notorious algae, Alexandrium minutum and Gymnodinium catenatum, which have similar paralytic shellfish toxin (PST) profiles. Using techniques including electron microscopy and transcriptome analysis, marked disruptions in G. catenatum intracellular microenvironment were observed under BECs pressure, encompassing thylakoid membrane deformations, pyrenoid matrix shrinkage and starch sheaths disappearance. In addition, the upregulation of gene clusters responsible for photosystem-I Lhca1/4 and Rubisco were determined, leading to weaken photon captures and CO2 assimilation. The redistribution of lipids and proteins occurred at the subcellular level based on in situ focal plane array FTIR imaging approved the damages. Our findings illuminated an intense but underestimated interspecies interaction triggered by BECs, which is responsible for dysregulating photosynthesis and organelle function in inferior algae and may potentially account for fitness alteration in phytoplankton community.
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Affiliation(s)
- Huige Guo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Xiaochen Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Changlin Li
- Marine Science and Technology College, Zhejiang Ocean University, Zhoushan, China
| | - Hala F Mohamed
- Department of Botany & Microbiology, (Girls Branch), Faculty of Science, Al-Azhar University, Cairo, Egypt
| | - Dawei Li
- College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Lianghui Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Hongzhe Chen
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Kunning Lin
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Shuyuan Huang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Jinling Pang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Yuanbiao Zhang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
| | - Bernd Krock
- Helmholtz Center for Polar and Marine Research, Alfred Wegener Institute, Bremerhaven, Germany
| | - Zhaohe Luo
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, China
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3
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Fang J, Zheng L, Liu G, Zhu H. Comparative Analysis of Chloroplast Genomes in Cephaleuros and Its Related Genus ( Trentepohlia): Insights into Adaptive Evolution. Genes (Basel) 2024; 15:839. [PMID: 39062618 PMCID: PMC11275322 DOI: 10.3390/genes15070839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/22/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
Cephaleuros species are well-known as plant pathogens that cause red rust or algae spot diseases in many economically cultivated plants that grow in shady and humid environments. Despite their prevalence, the adaptive evolution of these pathogens remains poorly understood. We sequenced and characterized three Cephaleuros (Cephaleuros lagerheimii, Cephaleuros diffusus, and Cephaleuros virescens) chloroplast genomes, and compared them with seven previously reported chloroplast genomes. The chloroplast sequences of C. lagerheimii, C. diffusus, and C. virescens were 480,613 bp, 383,846 bp, and 472,444 bp in length, respectively. These chloroplast genomes encoded 94 genes, including 27 tRNA genes, 3 rRNA genes, and 64 protein-coding genes. Comparative analysis uncovered that the variation in genome size was principally due to the length of intergenic spacer sequences, followed by introns. Furthermore, several highly variable regions (trnY-GTA, trnL-TAG, petA, psbT, trnD-GTC, trnL-TAA, ccsA, petG, psaA, psaB, rps11, rps2, and rps14) were identified. Codon bias analysis revealed that the codon usage pattern of Cephaleuros is predominantly shaped by natural selection. Additionally, six chloroplast protein-coding genes (atpF, chlN, psaA, psaB, psbA, and rbcL) were determined to be under positive selection, suggesting they may play a vital roles in the adaptation of Cephaleuros to low-light intensity habitats.
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Affiliation(s)
- Jiao Fang
- Wuhan Institute of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan 430056, China;
| | - Lingling Zheng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (L.Z.); (G.L.)
| | - Guoxiang Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (L.Z.); (G.L.)
| | - Huan Zhu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (L.Z.); (G.L.)
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Kelly MG, Mann DG, Taylor JD, Juggins S, Walsh K, Pitt JA, Read DS. Maximising environmental pressure-response relationship signals from diatom-based metabarcoding in rivers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169445. [PMID: 38159778 DOI: 10.1016/j.scitotenv.2023.169445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/28/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024]
Abstract
DNA metabarcoding has been performed on a large number of river phytobenthos samples collected from the UK, using rbcL primers optimised for diatoms. Within this dataset the composition of non-diatom sequence reads was studied and the effect of including these in models for evaluating the nutrient gradient was assessed. Whilst many non-diatom taxonomic groups were detected, few contained the full diversity expected in riverine environments. This may be due to the performance of the current primers in characterising the wider phytobenthic community and influenced by the sampling method employed, as both were developed specifically for diatoms. Nevertheless, the study identified considerable diversity in some groups, e.g. Eustigmatophyceae and a wider distribution than previously thought for freshwater Phaeophyceae. These results offer a strong case for the benefits of metabarcoding for expanding knowledge of aquatic biodiversity in the UK and elsewhere. Many of the ASVs associated with non-diatoms showed significant pressure responses; however, models that included non-diatoms had similar predictive strength to those based on diatoms alone. Whilst limitations of the primers for assessing non-diatoms may play a role in explaining these results, the diatoms provide a strong signal along the nutrient gradient and other algae, therefore, add little unique information. We recommend that future developments should use ASVs to calculate metrics, with links to reference databases made as a final step to generate lists of taxa to support interpretation. Any further exploration of the potential of non-diatoms would benefit from access to a well-curated reference database, similar to diat.barcode. Such a database does not yet exist, and we caution against the indiscriminate use of NCBI GenBank as a taxonomic resource as many rbcL sequences deposited have not been curated.
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Affiliation(s)
- Martyn G Kelly
- Bowburn Consultancy, 11 Monteigne Drive, Bowburn, Durham DH6 5QB, UK; School of Geography, Nottingham University, Nottingham NG7 2RD, UK.
| | - David G Mann
- Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, Scotland, UK; Marine and Continental Waters, Institute for Food and Agricultural Research and Technology (IRTA), Crta de Poble Nou Km 5.5, E-43540 La Ràpita, Catalunya, Spain
| | - Joe D Taylor
- UK Centre for Ecology & Hydrology (UKCEH), Wallingford, Oxfordshire OX10 8BB, UK
| | - Stephen Juggins
- School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Kerry Walsh
- Chief Scientist's Group, Environment Agency, Deanery Road, Bristol BS1 5AH, UK
| | - Jo-Anne Pitt
- Chief Scientist's Group, Environment Agency, Deanery Road, Bristol BS1 5AH, UK
| | - Daniel S Read
- UK Centre for Ecology & Hydrology (UKCEH), Wallingford, Oxfordshire OX10 8BB, UK
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5
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Lee Y, Cho CH, Noh C, Yang JH, Park SI, Lee YM, West JA, Bhattacharya D, Jo K, Yoon HS. Origin of minicircular mitochondrial genomes in red algae. Nat Commun 2023; 14:3363. [PMID: 37291154 PMCID: PMC10250338 DOI: 10.1038/s41467-023-39084-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/30/2023] [Indexed: 06/10/2023] Open
Abstract
Eukaryotic organelle genomes are generally of conserved size and gene content within phylogenetic groups. However, significant variation in genome structure may occur. Here, we report that the Stylonematophyceae red algae contain multipartite circular mitochondrial genomes (i.e., minicircles) which encode one or two genes bounded by a specific cassette and a conserved constant region. These minicircles are visualized using fluorescence microscope and scanning electron microscope, proving the circularity. Mitochondrial gene sets are reduced in these highly divergent mitogenomes. Newly generated chromosome-level nuclear genome assembly of Rhodosorus marinus reveals that most mitochondrial ribosomal subunit genes are transferred to the nuclear genome. Hetero-concatemers that resulted from recombination between minicircles and unique gene inventory that is responsible for mitochondrial genome stability may explain how the transition from typical mitochondrial genome to minicircles occurs. Our results offer inspiration on minicircular organelle genome formation and highlight an extreme case of mitochondrial gene inventory reduction.
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Affiliation(s)
- Yongsung Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Chung Hyun Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Chanyoung Noh
- Department of Chemistry, Sogang University, Seoul, 04107, Korea
| | - Ji Hyun Yang
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Seung In Park
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Yu Min Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - John A West
- School of Biosciences 2, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, 08901, USA
| | - Kyubong Jo
- Department of Chemistry, Sogang University, Seoul, 04107, Korea.
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea.
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6
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Pawlak K, Błażej P, Mackiewicz D, Mackiewicz P. The Influence of the Selection at the Amino Acid Level on Synonymous Codon Usage from the Viewpoint of Alternative Genetic Codes. Int J Mol Sci 2023; 24:ijms24021185. [PMID: 36674703 PMCID: PMC9866869 DOI: 10.3390/ijms24021185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/19/2022] [Accepted: 12/30/2022] [Indexed: 01/11/2023] Open
Abstract
Synonymous codon usage can be influenced by mutations and/or selection, e.g., for speed of protein translation and correct folding. However, this codon bias can also be affected by a general selection at the amino acid level due to differences in the acceptance of the loss and generation of these codons. To assess the importance of this effect, we constructed a mutation-selection model model, in which we generated almost 90,000 stationary nucleotide distributions produced by mutational processes and applied a selection based on differences in physicochemical properties of amino acids. Under these conditions, we calculated the usage of fourfold degenerated (4FD) codons and compared it with the usage characteristic of the pure mutations. We considered both the standard genetic code (SGC) and alternative genetic codes (AGCs). The analyses showed that a majority of AGCs produced a greater 4FD codon bias than the SGC. The mutations producing more thymine or adenine than guanine and cytosine increased the differences in usage. On the other hand, the mutational pressures generating a lot of cytosine or guanine with a low content of adenine and thymine decreased this bias because the nucleotide content of most 4FD codons stayed in the compositional equilibrium with these pressures. The comparison of the theoretical results with those for real protein coding sequences showed that the influence of selection at the amino acid level on the synonymous codon usage cannot be neglected. The analyses indicate that the effect of amino acid selection cannot be disregarded and that it can interfere with other selection factors influencing codon usage, especially in AT-rich genomes, in which AGCs are usually used.
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7
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Liu F, Chen N, Wang H, Li J, Wang J, Qu F. Novel insights into chloroplast genome evolution in the green macroalgal genus Ulva (Ulvophyceae, Chlorophyta). FRONTIERS IN PLANT SCIENCE 2023; 14:1126175. [PMID: 37143870 PMCID: PMC10151680 DOI: 10.3389/fpls.2023.1126175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 04/03/2023] [Indexed: 05/06/2023]
Abstract
To understand the evolutionary driving forces of chloroplast (or plastid) genomes (plastomes) in the green macroalgal genus Ulva (Ulvophyceae, Chlorophyta), in this study, we sequenced and constructed seven complete chloroplast genomes from five Ulva species, and conducted comparative genomic analysis of Ulva plastomes in Ulvophyceae. Ulva plastome evolution reflects the strong selection pressure driving the compactness of genome organization and the decrease of overall GC composition. The overall plastome sequences including canonical genes, introns, derived foreign sequences and non-coding regions show a synergetic decrease in GC content at varying degrees. Fast degeneration of plastome sequences including non-core genes (minD and trnR3), derived foreign sequences, and noncoding spacer regions was accompanied by the marked decrease of their GC composition. Plastome introns preferentially resided in conserved housekeeping genes with high GC content and long length, as might be related to high GC content of target site sequences recognized by intron-encoded proteins (IEPs), and to more target sites contained by long GC-rich genes. Many foreign DNA sequences integrated into different intergenic regions contain some homologous specific orfs with high similarity, indicating that they could have been derived from the same origin. The invasion of foreign sequences seems to be an important driving force for plastome rearrangement in these IR-lacking Ulva cpDNAs. Gene partitioning pattern has changed and distribution range of gene clusters has expanded after the loss of IR, indicating that genome rearrangement was more extensive and more frequent in Ulva plastomes, which was markedly different from that in IR-containing ulvophycean plastomes. These new insights greatly enhance our understanding of plastome evolution in ecologically important Ulva seaweeds.
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Affiliation(s)
- Feng Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, China
- Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, China
- *Correspondence: Feng Liu, ;
| | - Nansheng Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, China
- Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Hongshu Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, China
- Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Jiamin Li
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, China
- Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Jing Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, China
- Marine Ecology and Environmental Science Laboratory, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, Shandong, China
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Fan Qu
- Harbin University of Science and Technology, Weihai, Shandong, China
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Xiang QP, Tang JY, Yu JG, Smith DR, Zhu YM, Wang YR, Kang JS, Yang J, Zhang XC. The evolution of extremely diverged plastomes in Selaginellaceae (lycophyte) is driven by repeat patterns and the underlying DNA maintenance machinery. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:768-784. [PMID: 35648423 DOI: 10.1111/tpj.15851] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/25/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Two factors are proposed to account for the unusual features of organellar genomes: the disruptions of organelle-targeted DNA replication, repair, and recombination (DNA-RRR) systems in the nuclear genome and repetitive elements in organellar genomes. Little is known about how these factors affect organellar genome evolution. The deep-branching vascular plant family Selaginellaceae is known to have a deficient DNA-RRR system and convergently evolved organellar genomes. However, we found that the plastid genome (plastome) of Selaginella sinensis has extremely accelerated substitution rates, a low GC content, pervasive repeat elements, a dynamic network structure, and it lacks direct or inverted repeats. Unexpectedly, its organelle DNA-RRR system is short of a plastid-targeted Recombinase A1 (RecA1) and a mitochondrion-targeted RecA3, in line with other explored Selaginella species. The plastome contains a large collection of short- and medium-sized repeats. Given the absence of RecA1 surveillance, we propose that these repeats trigger illegitimate recombination, accelerated mutation rates, and structural instability. The correlations between repeat quantity and architectural complexity in the Selaginella plastomes support these conclusions. We, therefore, hypothesize that the interplay of the deficient DNA-RRR system and the high repeat content has led to the extraordinary divergence of the S. sinensis plastome. Our study not only sheds new light on the mechanism of plastome divergence by emphasizing the power of cytonuclear integration, but it also reconciles the longstanding contradiction on the effects of DNA-RRR system disruption on genome structure evolution.
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Affiliation(s)
- Qiao-Ping Xiang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
| | - Jun-Yong Tang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ji-Gao Yu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - David Roy Smith
- Department of Biology, University of Western Ontario, London, N6A 5B7, Ontario, Canada
| | - Yan-Mei Zhu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
| | - Ya-Rong Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
| | - Jong-Soo Kang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
| | - Jie Yang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xian-Chun Zhang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, The Chinese Academy of Sciences, Beijing, 100093, China
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9
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Domb K, Wang N, Hummel G, Liu C. Spatial Features and Functional Implications of Plant 3D Genome Organization. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:173-200. [PMID: 35130445 DOI: 10.1146/annurev-arplant-102720-022810] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The advent of high-throughput sequencing-based methods for chromatin conformation, accessibility, and immunoprecipitation assays has been a turning point in 3D genomics. Altogether, these new tools have been pushing upward the interpretation of pioneer cytogenetic evidence for a higher order in chromatin packing. Here, we review the latest development in our understanding of plant spatial genome structures and different levels of organization and discuss their functional implications. Then, we spotlight the complexity of organellar (i.e., mitochondria and plastids) genomes and discuss their 3D packing into nucleoids. Finally, we propose unaddressed research axes to investigate functional links between chromatin-like dynamics and transcriptional regulation within organellar nucleoids.
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Affiliation(s)
- Katherine Domb
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Nan Wang
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Guillaume Hummel
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
| | - Chang Liu
- Institute of Biology, University of Hohenheim, Stuttgart, Germany;
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10
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Hou Z, Ma X, Shi X, Li X, Yang L, Xiao S, De Clerck O, Leliaert F, Zhong B. Phylotranscriptomic insights into a Mesoproterozoic-Neoproterozoic origin and early radiation of green seaweeds (Ulvophyceae). Nat Commun 2022; 13:1610. [PMID: 35318329 PMCID: PMC8941102 DOI: 10.1038/s41467-022-29282-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 03/09/2022] [Indexed: 01/09/2023] Open
Abstract
The Ulvophyceae, a major group of green algae, is of particular evolutionary interest because of its remarkable morphological and ecological diversity. Its phylogenetic relationships and diversification timeline, however, are still not fully resolved. In this study, using an extensive nuclear gene dataset, we apply coalescent- and concatenation-based approaches to reconstruct the phylogeny of the Ulvophyceae and to explore the sources of conflict in previous phylogenomic studies. The Ulvophyceae is recovered as a paraphyletic group, with the Bryopsidales being a sister group to the Chlorophyceae, and the remaining taxa forming a clade (Ulvophyceae sensu stricto). Molecular clock analyses with different calibration strategies emphasize the large impact of fossil calibrations, and indicate a Meso-Neoproterozoic origin of the Ulvophyceae (sensu stricto), earlier than previous estimates. The results imply that ulvophyceans may have had a profound influence on oceanic redox structures and global biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition. “Ulvophyceae is a remarkably morphologically and ecologically diverse clade of green algae. Here, the authors reconstruct the Ulvophyceae phylogeny, showing that these algae originated earlier than expected and may have influenced biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition.”
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Affiliation(s)
- Zheng Hou
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xiaoya Ma
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xuan Shi
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xi Li
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shuhai Xiao
- Department of Geosciences and Global Change Center, Virginia Tech, Blacksburg, VA, USA
| | - Olivier De Clerck
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
| | - Frederik Leliaert
- Phycology Research Group and Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium.,Meise Botanic Garden, Meise, Belgium
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China.
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11
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Fang J, Chen Y, Liu G, Verbruggen H, Zhu H. Chloroplast Genome Traits Correlate With Organismal Complexity and Ecological Traits in Chlorophyta. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.791166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A positive relationship between cell size and chloroplast genome size within chloroplast-bearing protists has been hypothesized in the past and shown in some case studies, but other factors influencing chloroplast genome size during the evolution of chlorophyte algae have been less studied. We study chloroplast genome size and GC content as a function of habitats and cell size of chlorophyte algae. The chloroplast genome size of green algae in freshwater, marine and terrestrial habitats was differed significantly, with terrestrial algae having larger chloroplast genome sizes in general. The most important contributor to these enlarged genomes in terrestrial species was the length of intergenic regions. There was no clear difference in the GC content of chloroplast genomes from the three habitats categories. Functional morphological categories also showed differences in chloroplast genome size, with filamentous algae having substantially larger genomes than other forms of algae, and foliose algae had lower GC content than other groups. Chloroplast genome size showed no significant differences among the classes Ulvophyceae, Trebouxiophyceae, and Chlorophyceae, but the GC content of Chlorophyceae chloroplast genomes was significantly lower than that of Ulvophyceae and Trebouxiophyceae. There was a certain positive relationship between chloroplast genome size and cell size for the Chlorophyta as a whole and within each of three major classes. Our data also confirmed previous reports that ancestral quadripartite architecture had been lost many times independently in Chlorophyta. Finally, the comparison of the phenotype of chlorophytes algae harboring plastids uncovered that most of the investigated Chlorophyta algae housed a single plastid per cell.
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Gulbrandsen ØS, Andresen IJ, Krabberød AK, Bråte J, Shalchian-Tabrizi K. Phylogenomic analysis restructures the ulvophyceae. JOURNAL OF PHYCOLOGY 2021; 57:1223-1233. [PMID: 33721355 DOI: 10.1111/jpy.13168] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 01/26/2021] [Accepted: 02/03/2021] [Indexed: 06/12/2023]
Abstract
Here, we present new transcriptome sequencing data from seven species of Dasycladales (Ulvophyceae) and a phylogenomic analysis of the Chlorophyta with a particular focus on Ulvophyceae. We have focused on a broad selection of green algal groups and carefully selected genes suitable for reconstructing deep eukaryote evolutionary histories. Increasing the taxon sampling of Dasycladales restructures the Ulvophyceae by identifying Dasycladales as closely related to Scotinosphaerales and Oltmannsiellopsidales. Contrary to previous studies, we do not find support for a close relationship between Dasycladales and a group with Cladophorales and Trentepohliales. Instead, the latter group is sister to the remainder of the Ulvophyceae. Furthermore, our analyses show high and consistent statistical support for a sister relationship between Bryopsidales and Chlorophyceae in trees generated with both homogeneous and heterogeneous (heterotachy) evolutionary models. Our study provides a new framework for interpreting the evolutionary history of Ulvophyceae and the evolution of cellular morphologies.
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Affiliation(s)
- Øyvind Saetren Gulbrandsen
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Kristine Bonnevies Hus, Blindernveien 31, 0316, Oslo, Norway
- Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Centre for Integrative Genetics, Norwegian University of Life Sciences, Ås, Norway
| | - Ina Jungersen Andresen
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Kristine Bonnevies Hus, Blindernveien 31, 0316, Oslo, Norway
| | - Anders Kristian Krabberød
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Kristine Bonnevies Hus, Blindernveien 31, 0316, Oslo, Norway
| | - Jon Bråte
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Kristine Bonnevies Hus, Blindernveien 31, 0316, Oslo, Norway
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Kamran Shalchian-Tabrizi
- Centre for Integrative Microbial Evolution (CIME), Centre for Epigenetics, Development and Evolution (CEDE), Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Kristine Bonnevies Hus, Blindernveien 31, 0316, Oslo, Norway
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13
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Li X, Hou Z, Xu C, Shi X, Yang L, Lewis LA, Zhong B. Large Phylogenomic Data sets Reveal Deep Relationships and Trait Evolution in Chlorophyte Green Algae. Genome Biol Evol 2021; 13:6265471. [PMID: 33950183 PMCID: PMC8271138 DOI: 10.1093/gbe/evab101] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2021] [Indexed: 12/01/2022] Open
Abstract
The chlorophyte green algae (Chlorophyta) are species-rich ancient groups ubiquitous in various habitats with high cytological diversity, ranging from microscopic to macroscopic organisms. However, the deep phylogeny within core Chlorophyta remains unresolved, in part due to the relatively sparse taxon and gene sampling in previous studies. Here we contribute new transcriptomic data and reconstruct phylogenetic relationships of core Chlorophyta based on four large data sets up to 2,698 genes of 70 species, representing 80% of extant orders. The impacts of outgroup choice, missing data, bootstrap-support cutoffs, and model misspecification in phylogenetic inference of core Chlorophyta are examined. The species tree topologies of core Chlorophyta from different analyses are highly congruent, with strong supports at many relationships (e.g., the Bryopsidales and the Scotinosphaerales-Dasycladales clade). The monophyly of Chlorophyceae and of Trebouxiophyceae as well as the uncertain placement of Chlorodendrophyceae and Pedinophyceae corroborate results from previous studies. The reconstruction of ancestral scenarios illustrates the evolution of the freshwater-sea and microscopic–macroscopic transition in the Ulvophyceae, and the transformation of unicellular→colonial→multicellular in the chlorophyte green algae. In addition, we provided new evidence that serine is encoded by both canonical codons and noncanonical TAG code in Scotinosphaerales, and stop-to-sense codon reassignment in the Ulvophyceae has originated independently at least three times. Our robust phylogenetic framework of core Chlorophyta unveils the evolutionary history of phycoplast, cyto-morphology, and noncanonical genetic codes in chlorophyte green algae.
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Affiliation(s)
- Xi Li
- College of Life Sciences, Nanjing Normal University, China
| | - Zheng Hou
- College of Life Sciences, Nanjing Normal University, China
| | - Chenjie Xu
- College of Life Sciences, Nanjing Normal University, China
| | - Xuan Shi
- College of Life Sciences, Nanjing Normal University, China
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, China
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, China
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14
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Identification of polycistronic transcriptional units and non-canonical introns in green algal chloroplasts based on long-read RNA sequencing data. BMC Genomics 2021; 22:298. [PMID: 33892645 PMCID: PMC8063479 DOI: 10.1186/s12864-021-07598-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 04/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chloroplasts are important semi-autonomous organelles in plants and algae. Unlike higher plants, the chloroplast genomes of green algal linage have distinct features both in organization and expression. Despite the architecture of chloroplast genome having been extensively studied in higher plants and several model species of algae, little is known about the transcriptional features of green algal chloroplast-encoded genes. RESULTS Based on full-length cDNA (Iso-Seq) sequencing, we identified widely co-transcribed polycistronic transcriptional units (PTUs) in the green alga Caulerpa lentillifera. In addition to clusters of genes from the same pathway, we identified a series of PTUs of up to nine genes whose function in the plastid is not understood. The RNA data further allowed us to confirm widespread expression of fragmented genes and conserved open reading frames, which are both important features in green algal chloroplast genomes. In addition, a newly fragmented gene specific to C. lentillifera was discovered, which may represent a recent gene fragmentation event in the chloroplast genome. With the newly annotated exon-intron boundary information, gene structural annotation was greatly improved across the siphonous green algae lineages. Our data also revealed a type of non-canonical Group II introns, with a deviant secondary structure and intronic ORFs lacking known splicing or mobility domains. These widespread introns have conserved positions in their genes and are excised precisely despite lacking clear consensus intron boundaries. CONCLUSION Our study fills important knowledge gaps in chloroplast genome organization and transcription in green algae, and provides new insights into expression of polycistronic transcripts, freestanding ORFs and fragmented genes in algal chloroplast genomes. Moreover, we revealed an unusual type of Group II intron with distinct features and conserved positions in Bryopsidales. Our data represents interesting additions to knowledge of chloroplast intron structure and highlights clusters of uncharacterized genes that probably play important roles in plastids.
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15
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Fang J, Liu B, Liu G, Verbruggen H, Zhu H. Six Newly Sequenced Chloroplast Genomes From Trentepohliales: The Inflated Genomes, Alternative Genetic Code and Dynamic Evolution. FRONTIERS IN PLANT SCIENCE 2021; 12:780054. [PMID: 34956275 PMCID: PMC8692980 DOI: 10.3389/fpls.2021.780054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/15/2021] [Indexed: 05/17/2023]
Abstract
Cephaleuros is often known as an algal pathogen with 19 taxonomically valid species, some of which are responsible for red rust and algal spot diseases in vascular plants. No chloroplast genomes have yet been reported in this genus, and the limited genetic information is an obstacle to understanding the evolution of this genus. In this study, we sequenced six new Trentepohliales chloroplast genomes, including four Cephaleuros and two Trentepohlia. The chloroplast genomes of Trentepohliales are large compared to most green algae, ranging from 216 to 408 kbp. They encode between 93 and 98 genes and have a GC content of 26-36%. All new chloroplast genomes were circular-mapping and lacked a quadripartite structure, in contrast to the previously sequenced Trentepohlia odorata, which does have an inverted repeat. The duplicated trnD -GTC, petD, and atpA genes in C. karstenii may be remnants of the IR region and shed light on its reduction. Chloroplast genes of Trentepohliales show elevated rates of evolution, strong rearrangement dynamics and several genes display an alternative genetic code with reassignment of the UGA/UAG codon presumably coding for arginine. Our results present the first whole chloroplast genome of the genus Cephaleuros and enrich the chloroplast genome resources of Trentepohliales.
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Affiliation(s)
- Jiao Fang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Benwen Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Guoxiang Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, VIC, Australia
| | - Huan Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Huan Zhu,
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16
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Meade MJ, Proulex GCR, Manoylov KM, Cahoon AB. Chloroplast mRNAs are 3' polyuridylylated in the Green Alga Pithophora roettleri (Cladophorales). JOURNAL OF PHYCOLOGY 2020; 56:1124-1134. [PMID: 32464681 DOI: 10.1111/jpy.13033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
Species within the green algal order Cladophorales have an unconventional plastome structure where individual coding regions or small numbers of genes occur as linear single-stranded DNAs folded into hairpin structures. Another group of photosynthetic organisms with an equivalently reduced chloroplast genome are the peridinin dinoflagellates of the Alveolata eukaryotic lineage whose plastomes are mini-circles carrying one or a few genes required for photosynthesis. One unusual aspect of the Alveolata is the polyuridylylation of mRNA 3' ends among peridinin dinoflagellates and the chromerid algae. This study was conducted to understand if an unconventional highly reduced plastome structure co-occurs with unconventional RNA processing. To address this, the 5' and 3' mRNA termini of the known chloroplast genes of Pithophora roettleri (order Cladophorales) were analyzed for evidence of post-transcriptional processing. Circular Reverse Transcriptase PCR (cRT-PCR) followed by deep sequencing of the amplicons was used to analyze 5' and 3' mRNA termini. Evidence of several processing events were collected, most notably the 3' termini of six of the eight genes were polyuridylylated, which has not been reported for any lineage outside of the Alveolata. Other processing events include poly(A) and heteropolymeric 3' additions, 5' primary transcript start sites, as well as the presence of circularized RNAs. Five other species representing other green algal lineages were also tested and poly(U) additions appear to be limited to the order Cladophorales. These results demonstrate that chloroplast mRNA polyuridylylation is not the sole provenance of photosynthetic alveolates and may have convergently evolved in two distinct photosynthetic lineages.
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Affiliation(s)
- Marcus J Meade
- Department of Natural Sciences, The University of Virginia's College at Wise, 1 College Ave., Wise, Virginia, 24293, USA
| | - Grayson C R Proulex
- Department of Natural Sciences, The University of Virginia's College at Wise, 1 College Ave., Wise, Virginia, 24293, USA
| | - Kalina M Manoylov
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, Georgia, 31061, USA
| | - A Bruce Cahoon
- Department of Natural Sciences, The University of Virginia's College at Wise, 1 College Ave., Wise, Virginia, 24293, USA
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17
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Dorrell RG. Convergence in the RNA processing of fractured algal organelle genomes. JOURNAL OF PHYCOLOGY 2020; 56:1121-1123. [PMID: 33460118 DOI: 10.1111/jpy.13039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Affiliation(s)
- Richard G Dorrell
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
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18
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Murúa P, Edrada-Ebel R, Muñoz L, Soldatou S, Legrave N, Müller DG, Patiño DJ, van West P, Küpper FC, Westermeier R, Ebel R, Peters AF. Morphological, genotypic and metabolomic signatures confirm interfamilial hybridization between the ubiquitous kelps Macrocystis (Arthrothamnaceae) and Lessonia (Lessoniaceae). Sci Rep 2020; 10:8279. [PMID: 32427928 PMCID: PMC7237481 DOI: 10.1038/s41598-020-65137-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 04/28/2020] [Indexed: 01/20/2023] Open
Abstract
Macrocystis pyrifera and Lessonia spicata are economically and ecologically relevant brown seaweeds that recently have been classified as members of two separated families within Laminariales (kelps). Here we describe for the first time the Macrocystis pyrifera x Lessonia spicata hybridization in the wild (Chiloe Island, Southeastern Pacific), where populations of the two parents exist sympatrically. Externally, this hybrid exhibited typical features of its parents M. pyrifera (cylindrical and flexible distal stipes, serrate frond margins and presence of sporophylls) and L. spicata (rigid and flat main stipe and first bifurcation), as well as intermediate features between them (thick unfused haptera in the holdfast). Histological sections revealed the prevalence of mucilage ducts within stipes and fronds (absent in Lessonia) and fully developed unilocular sporangia in the sporophylls. Molecular analyses confirmed the presence of the two parental genotypes for ITS1 nrDNA and the M. pyrifera genotype for two predominantly maternally inherited cytoplasmic markers (COI and rbcLS spacer) in the tissue of the hybrid. A metabolome-wide approach revealed that this hybrid is more chemically reminiscent to M. pyrifera. Nevertheless, several hits were identified as Lessonia exclusive or more remarkably, not present in any of the parent. Meiospores developed into apparently fertile gametophytes, which gave rise to F1 sporophytes that reached several millimeters before suddenly dying. In-vitro reciprocal crossing of Mar Brava gametophytes from both species revealed that although it is rare, interfamilial hybridization between the two species is possible but mostly overcome by pseudogamy of female gametophytes.
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Affiliation(s)
- Pedro Murúa
- Instituto de Acuicultura, Universidad Austral de Chile, Sede Puerto Montt, PO box 1327, Puerto Montt, Chile.
- The Scottish Association for Marine Science, Scottish Marine Institute, Culture Collection for Algae and Protozoa, Oban, Argyll, PA37 1QA, Scotland, United Kingdom.
- Aberdeen Oomycete Group, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, AB25 2ZD, Aberdeen, United Kingdom.
| | - RuAngelie Edrada-Ebel
- The Natural Products Metabolomics Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, The John Arbuthnott Building, 161 Cathedral Street, Glasgow, G4 0RE, United Kingdom
| | - Liliana Muñoz
- Aberdeen Oomycete Group, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, AB25 2ZD, Aberdeen, United Kingdom
| | - Sylvia Soldatou
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen, AB24 3UE, United Kingdom
| | - Nathalie Legrave
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen, AB24 3UE, United Kingdom
| | - Dieter G Müller
- Fachbereich Biologie der Universität Konstanz, D-78457, Konstanz, Germany
| | - David J Patiño
- Instituto de Acuicultura, Universidad Austral de Chile, Sede Puerto Montt, PO box 1327, Puerto Montt, Chile
| | - Pieter van West
- Aberdeen Oomycete Group, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, AB25 2ZD, Aberdeen, United Kingdom
| | - Frithjof C Küpper
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen, AB24 3UE, United Kingdom
- School of Biological Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, Scotland, UK
| | - Renato Westermeier
- Instituto de Acuicultura, Universidad Austral de Chile, Sede Puerto Montt, PO box 1327, Puerto Montt, Chile
| | - Rainer Ebel
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Meston Building, Meston Walk, Old Aberdeen, AB24 3UE, United Kingdom
| | - Akira F Peters
- School of Biological Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen, AB24 3UU, Scotland, UK
- Bezhin Rosko, 40 rue des pêcheurs, 29250, Santec, Brittany, France
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19
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Žihala D, Eliáš M. Evolution and Unprecedented Variants of the Mitochondrial Genetic Code in a Lineage of Green Algae. Genome Biol Evol 2020; 11:2992-3007. [PMID: 31617565 PMCID: PMC6821328 DOI: 10.1093/gbe/evz210] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2019] [Indexed: 12/15/2022] Open
Abstract
Mitochondria of diverse eukaryotes have evolved various departures from the standard genetic code, but the breadth of possible modifications and their phylogenetic distribution are known only incompletely. Furthermore, it is possible that some codon reassignments in previously sequenced mitogenomes have been missed, resulting in inaccurate protein sequences in databases. Here we show, considering the distribution of codons at conserved amino acid positions in mitogenome-encoded proteins, that mitochondria of the green algal order Sphaeropleales exhibit a diversity of codon reassignments, including previously missed ones and some that are unprecedented in any translation system examined so far, necessitating redefinition of existing translation tables and creating at least seven new ones. We resolve a previous controversy concerning the meaning the UAG codon in Hydrodictyaceae, which beyond any doubt encodes alanine. We further demonstrate that AGG, sometimes together with AGA, encodes alanine instead of arginine in diverse sphaeroplealeans. Further newly detected changes include Arg-to-Met reassignment of the AGG codon and Arg-to-Leu reassignment of the CGG codon in particular species. Analysis of tRNAs specified by sphaeroplealean mitogenomes provides direct support for and molecular underpinning of the proposed reassignments. Furthermore, we point to unique mutations in the mitochondrial release factor mtRF1a that correlate with changes in the use of termination codons in Sphaeropleales, including the two independent stop-to-sense UAG reassignments, the reintroduction of UGA in some Scenedesmaceae, and the sense-to-stop reassignment of UCA widespread in the group. Codon disappearance seems to be the main drive of the dynamic evolution of the mitochondrial genetic code in Sphaeropleales.
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Affiliation(s)
- David Žihala
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Czech Republic.,Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Czech Republic.,Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
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20
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Repetti SI, Jackson CJ, Judd LM, Wick RR, Holt KE, Verbruggen H. The inflated mitochondrial genomes of siphonous green algae reflect processes driving expansion of noncoding DNA and proliferation of introns. PeerJ 2020; 8:e8273. [PMID: 31915577 PMCID: PMC6944098 DOI: 10.7717/peerj.8273] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023] Open
Abstract
Within the siphonous green algal order Bryopsidales, the size and gene arrangement of chloroplast genomes has been examined extensively, while mitochondrial genomes have been mostly overlooked. The recently published mitochondrial genome of Caulerpa lentillifera is large with expanded noncoding DNA, but it remains unclear if this is characteristic of the entire order. Our study aims to evaluate the evolutionary forces shaping organelle genome dynamics in the Bryopsidales based on the C. lentillifera and Ostreobium quekettii mitochondrial genomes. In this study, the mitochondrial genome of O. quekettii was characterised using a combination of long and short read sequencing, and bioinformatic tools for annotation and sequence analyses. We compared the mitochondrial and chloroplast genomes of O. quekettii and C. lentillifera to examine hypotheses related to genome evolution. The O. quekettii mitochondrial genome is the largest green algal mitochondrial genome sequenced (241,739 bp), considerably larger than its chloroplast genome. As with the mtDNA of C. lentillifera, most of this excess size is from the expansion of intergenic DNA and proliferation of introns. Inflated mitochondrial genomes in the Bryopsidales suggest effective population size, recombination and/or mutation rate, influenced by nuclear-encoded proteins, differ between the genomes of mitochondria and chloroplasts, reducing the strength of selection to influence evolution of their mitochondrial genomes.
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Affiliation(s)
- Sonja I Repetti
- School of BioSciences, University of Melbourne, Melbourne, VIC, Australia
| | | | - Louise M Judd
- Department of Infectious Diseases, Monash University, Melbourne, VIC, Australia
| | - Ryan R Wick
- Department of Infectious Diseases, Monash University, Melbourne, VIC, Australia
| | - Kathryn E Holt
- Department of Infectious Diseases, Monash University, Melbourne, VIC, Australia
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, VIC, Australia
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21
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Rivero‐Müller A, Nees M. Preparing biomedical students for the unknown: Some unusual challenges for students to help them understand the fundamentals of empirical research. EMBO Rep 2019; 20:e49004. [PMID: 31523933 PMCID: PMC6776910 DOI: 10.15252/embr.201949004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Make teaching challenging again: a pedagogic approach to educate students on how to do science rather than learn about it.
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Affiliation(s)
- Adolfo Rivero‐Müller
- Department of Biochemistry and Molecular BiologyMedical University of LublinLublinPoland
- Faculty of Science and Engineering, Cell BiologyÅbo Akademi UniversityTurkuFinland
| | - Matthias Nees
- Department of Biochemistry and Molecular BiologyMedical University of LublinLublinPoland
- Institute of BiomedicineUniversity of TurkuTurkuFinland
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22
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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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23
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Abstract
A new study shows that Cladophorales green algae have the most unconventional chloroplast DNAs ever observed, whereby genes are located on small linear single-stranded palindromic elements. This puzzling architecture has parallels with mini-circular chloroplast genomes of dinoflagellates and raises many questions about how it arose and is maintained.
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24
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Characterization of the Chloroplast Genome of Trentepohlia odorata (Trentepohliales, Chlorophyta), and Discussion of its Taxonomy. Int J Mol Sci 2019; 20:ijms20071774. [PMID: 30974837 PMCID: PMC6480257 DOI: 10.3390/ijms20071774] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 01/12/2023] Open
Abstract
Trentepohliales is an aerial order of Chlorophyta with approximately 80 species distributed mainly in tropical and subtropical regions. The taxonomy of this genus is quite difficult and presents a challenge for many phycologists. Although plentiful molecular data is available, most of the sequences are not identified at the species level. In the present study, we described a new specimen with detailed morphological data and identified it as Trentepohlia odorata. A phylogenetic analysis showed T. odorata as a novel lineage in Trentepohliales. T. odorata has the closest relationship with T. annulata, which is expected since sporangia of both species are without stalk cell and with dorsal pore. Species with such morphological characteristics may represent deep lineages in Trentepohliales. Although an increasing number of chloroplast genomes of Ulvophyceae have been reported in recent years, the whole plastome of Trentepohliales has not yet been reported. Thus, the chloroplast genome of Trentepohlia odorata was reported in the present study. The whole plastome was 399,372 bp in length, with 63 predicted protein-coding genes, 31 tRNAs, and 3 rRNAs. Additionally, we annotated 95 free-standing open reading frames, of which seven were annotated with plastid origins, 16 with eukaryotic genome origins, and 33 with bacterial genome origins. Four rpo genes (rpoA, rpoB, rpoC1, and rpoC2) were annotated within ORF clusters. These four genes were fragmented into several (partial) ORFs by in-frame stop codons. Additionally, we detected a frame shift mutation in the rpoB gene. The phylogenetic analysis supported that Trentepohliales clustered with Dasycladales and nested into the BDT clade (Bryopsidales, Dasycladales and Trentepohliales). Our results present the first whole chloroplast genome of a species of Trentepohliales and provided new data for understanding the evolution of the chloroplast genome in Ulvophyceae.
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Williams AM, Friso G, van Wijk KJ, Sloan DB. Extreme variation in rates of evolution in the plastid Clp protease complex. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:243-259. [PMID: 30570818 DOI: 10.1111/tpj.14208] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/29/2018] [Accepted: 12/10/2018] [Indexed: 05/08/2023]
Abstract
Eukaryotic cells represent an intricate collaboration between multiple genomes, even down to the level of multi-subunit complexes in mitochondria and plastids. One such complex in plants is the caseinolytic protease (Clp), which plays an essential role in plastid protein turnover. The proteolytic core of Clp comprises subunits from one plastid-encoded gene (clpP1) and multiple nuclear genes. TheclpP1 gene is highly conserved across most green plants, but it is by far the fastest evolving plastid-encoded gene in some angiosperms. To better understand these extreme and mysterious patterns of divergence, we investigated the history ofclpP1 molecular evolution across green plants by extracting sequences from 988 published plastid genomes. We find thatclpP1 has undergone remarkably frequent bouts of accelerated sequence evolution and architectural changes (e.g. a loss of introns andRNA-editing sites) within seed plants. AlthoughclpP1 is often assumed to be a pseudogene in such cases, multiple lines of evidence suggest that this is rarely true. We applied comparative native gel electrophoresis of chloroplast protein complexes followed by protein mass spectrometry in two species within the angiosperm genusSilene, which has highly elevated and heterogeneous rates ofclpP1 evolution. We confirmed thatclpP1 is expressed as a stable protein and forms oligomeric complexes with the nuclear-encoded Clp subunits, even in one of the most divergentSilene species. Additionally, there is a tight correlation between amino acid substitution rates inclpP1 and the nuclear-encoded Clp subunits across a broad sampling of angiosperms, suggesting continuing selection on interactions within this complex.
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Affiliation(s)
- Alissa M Williams
- Department of Biology, Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Giulia Friso
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, NY, 14853, USA
| | - Klaas J van Wijk
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, NY, 14853, USA
| | - Daniel B Sloan
- Department of Biology, Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, 80523, USA
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Many alternative and theoretical genetic codes are more robust to amino acid replacements than the standard genetic code. J Theor Biol 2019; 464:21-32. [DOI: 10.1016/j.jtbi.2018.12.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 02/07/2023]
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Kim D, Lee J, Choi JW, Yang JH, Hwang IK, Yoon HS. Flip-flop organization in the chloroplast genome of Capsosiphon fulvescens (Ulvophyceae, Chlorophyta). JOURNAL OF PHYCOLOGY 2019; 55:214-223. [PMID: 30403403 DOI: 10.1111/jpy.12811] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
To better understand organelle genome evolution of the ulvophycean green alga Capsosiphon fulvescens, we sequenced and characterized its complete chloroplast genome. The circular chloroplast genome was 111,561 bp in length with 31.3% GC content that contained 108 genes including 77 protein-coding genes, two copies of rRNA operons, and 27 tRNAs. In this analysis, we found the two types of isoform, called heteroplasmy, were likely caused by a flip-flop organization. The flip-flop mechanism may have caused structural variation and gene conversion in the chloroplast genome of C. fulvescens. In a phylogenetic analysis based on all available ulvophycean chloroplast genome data, including a new C. fulvescens genome, we found three major conflicting signals for C. fulvescens and its sister taxon Pseudoneochloris marina within 70 individual genes: (i) monophyly with Ulotrichales, (ii) monophyly with Ulvales, and (iii) monophyly with the clade of Ulotrichales and Ulvales. Although the 70-gene concatenated phylogeny supported monophyly with Ulvales for both species, these complex phylogenetic signals of individual genes need further investigations using a data-rich approach (i.e., organelle genome data) from broader taxon sampling.
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Affiliation(s)
- Dongseok Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - JunMo Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Ji Won Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Ji Hyun Yang
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Il-Ki Hwang
- Aquatic Plant Variety Center, National Institute of Fisheries Science, Mokpo, 58746, Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
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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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Figueroa-Martinez F, Jackson C, Reyes-Prieto A. Plastid Genomes from Diverse Glaucophyte Genera Reveal a Largely Conserved Gene Content and Limited Architectural Diversity. Genome Biol Evol 2019; 11:174-188. [PMID: 30534986 PMCID: PMC6330054 DOI: 10.1093/gbe/evy268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2018] [Indexed: 12/30/2022] Open
Abstract
Plastid genome (ptDNA) data of Glaucophyta have been limited for many years to the genus Cyanophora. Here, we sequenced the ptDNAs of Gloeochaete wittrockiana, Cyanoptyche gloeocystis, Glaucocystis incrassata, and Glaucocystis sp. BBH. The reported sequences are the first genome-scale plastid data available for these three poorly studied glaucophyte genera. Although the Glaucophyta plastids appear morphologically “ancestral,” they actually bear derived genomes not radically different from those of red algae or viridiplants. The glaucophyte plastid coding capacity is highly conserved (112 genes shared) and the architecture of the plastid chromosomes is relatively simple. Phylogenomic analyses recovered Glaucophyta as the earliest diverging Archaeplastida lineage, but the position of viridiplants as the first branching group was not rejected by the approximately unbiased test. Pairwise distances estimated from 19 different plastid genes revealed that the highest sequence divergence between glaucophyte genera is frequently higher than distances between species of different classes within red algae or viridiplants. Gene synteny and sequence similarity in the ptDNAs of the two Glaucocystis species analyzed is conserved. However, the ptDNA of Gla. incrassata contains a 7.9-kb insertion not detected in Glaucocystis sp. BBH. The insertion contains ten open reading frames that include four coding regions similar to bacterial serine recombinases (two open reading frames), DNA primases, and peptidoglycan aminohydrolases. These three enzymes, often encoded in bacterial plasmids and bacteriophage genomes, are known to participate in the mobilization and replication of DNA mobile elements. It is therefore plausible that the insertion in Gla. incrassata ptDNA is derived from a DNA mobile element.
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Affiliation(s)
- Francisco Figueroa-Martinez
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada.,CONACyT-Universidad Autónoma Metropolitana Iztapalapa, Biotechnology Department, Mexico City, Mexico
| | - Christopher Jackson
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada.,School of Biosciences, University of Melbourne, Melbourne, Australia
| | - Adrian Reyes-Prieto
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada
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Cremen MCM, Leliaert F, Marcelino VR, Verbruggen H. Large Diversity of Nonstandard Genes and Dynamic Evolution of Chloroplast Genomes in Siphonous Green Algae (Bryopsidales, Chlorophyta). Genome Biol Evol 2018; 10:1048-1061. [PMID: 29635329 PMCID: PMC5888179 DOI: 10.1093/gbe/evy063] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Chloroplast genomes have undergone tremendous alterations through the evolutionary history of the green algae (Chloroplastida). This study focuses on the evolution of chloroplast genomes in the siphonous green algae (order Bryopsidales). We present five new chloroplast genomes, which along with existing sequences, yield a data set representing all but one families of the order. Using comparative phylogenetic methods, we investigated the evolutionary dynamics of genomic features in the order. Our results show extensive variation in chloroplast genome architecture and intron content. Variation in genome size is accounted for by the amount of intergenic space and freestanding open reading frames that do not show significant homology to standard plastid genes. We show the diversity of these nonstandard genes based on their conserved protein domains, which are often associated with mobile functions (reverse transcriptase/intron maturase, integrases, phage- or plasmid-DNA primases, transposases, integrases, ligases). Investigation of the introns showed proliferation of group II introns in the early evolution of the order and their subsequent loss in the core Halimedineae, possibly through RT-mediated intron loss.
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Affiliation(s)
| | - Frederik Leliaert
- Botanic Garden Meise, 1860 Meise, Belgium.,Department of Biology, Phycology Research Group, Ghent University, 9000 Ghent, Belgium
| | - Vanessa R Marcelino
- School of BioSciences, University of Melbourne, Parkville, Australia.,Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, and Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, New South Wales, Australia
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Parkville, Australia
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31
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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: 96] [Impact Index Per Article: 16.0] [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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32
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Gaouda H, Hamaji T, Yamamoto K, Kawai-Toyooka H, Suzuki M, Noguchi H, Minakuchi Y, Toyoda A, Fujiyama A, Nozaki H, Smith DR. Exploring the Limits and Causes of Plastid Genome Expansion in Volvocine Green Algae. Genome Biol Evol 2018; 10:2248-2254. [PMID: 30102347 PMCID: PMC6128376 DOI: 10.1093/gbe/evy175] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2018] [Indexed: 12/25/2022] Open
Abstract
Plastid genomes are not normally celebrated for being large. But researchers are steadily uncovering algal lineages with big and, in rare cases, enormous plastid DNAs (ptDNAs), such as volvocine green algae. Plastome sequencing of five different volvocine species has revealed some of the largest, most repeat-dense plastomes on record, including that of Volvox carteri (∼525 kb). Volvocine algae have also been used as models for testing leading hypotheses on organelle genome evolution (e.g., the mutational hazard hypothesis), and it has been suggested that ptDNA inflation within this group might be a consequence of low mutation rates and/or the transition from a unicellular to multicellular existence. Here, we further our understanding of plastome size variation in the volvocine line by examining the ptDNA sequences of the colonial species Yamagishiella unicocca and Eudorina sp. NIES-3984 and the multicellular Volvox africanus, which are phylogenetically situated between species with known ptDNA sizes. Although V. africanus is closely related and similar in multicellular organization to V. carteri, its ptDNA was much less inflated than that of V. carteri. Synonymous- and noncoding-site nucleotide substitution rate analyses of these two Volvox ptDNAs suggest that there are drastically different plastid mutation rates operating in the coding versus intergenic regions, supporting the idea that error-prone DNA repair in repeat-rich intergenic spacers is contributing to genome expansion. Our results reinforce the idea that the volvocine line harbors extremes in plastome size but ultimately shed doubt on some of the previously proposed hypotheses for ptDNA inflation within the lineage.
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Affiliation(s)
- Hager Gaouda
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Takashi Hamaji
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, Kyoto University, Japan
| | - Kayoko Yamamoto
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - Hiroko Kawai-Toyooka
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - Masahiro Suzuki
- Kobe University Research Center for Inland Seas, Awaji, Hyogo, Japan
| | - Hideki Noguchi
- Center for Genome Informatics, Joint Support-Center for Data Science Research, Research Organization of Information and Systems, Mishima, Shizuoka, Japan
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yohei Minakuchi
- Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
- Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Asao Fujiyama
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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33
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Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
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Jackson C, Knoll AH, Chan CX, Verbruggen H. Plastid phylogenomics with broad taxon sampling further elucidates the distinct evolutionary origins and timing of secondary green plastids. Sci Rep 2018; 8:1523. [PMID: 29367699 PMCID: PMC5784168 DOI: 10.1038/s41598-017-18805-w] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/15/2017] [Indexed: 11/08/2022] Open
Abstract
Secondary plastids derived from green algae occur in chlorarachniophytes, photosynthetic euglenophytes, and the dinoflagellate genus Lepidodinium. Recent advances in understanding the origin of these plastids have been made, but analyses suffer from relatively sparse taxon sampling within the green algal groups to which they are related. In this study we aim to derive new insights into the identity of the plastid donors, and when in geological time the independent endosymbiosis events occurred. We use newly sequenced green algal chloroplast genomes from carefully chosen lineages potentially related to chlorarachniophyte and Lepidodinium plastids, combined with recently published chloroplast genomes, to present taxon-rich phylogenetic analyses to further pinpoint plastid origins. We integrate phylogenies with fossil information and relaxed molecular clock analyses. Our results indicate that the chlorarachniophyte plastid may originate from a precusor of siphonous green algae or a closely related lineage, whereas the Lepidodinium plastid originated from a pedinophyte. The euglenophyte plastid putatively originated from a lineage of prasinophytes within the order Pyramimonadales. Our molecular clock analyses narrow in on the likely timing of the secondary endosymbiosis events, suggesting that the event leading to Lepidodinium likely occurred more recently than those leading to the chlorarachniophyte and photosynthetic euglenophyte lineages.
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Affiliation(s)
- Christopher Jackson
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia.
| | - Andrew H Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, 02138, USA
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, and School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Heroen Verbruggen
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
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Smith DR. Does Cell Size Impact Chloroplast Genome Size? FRONTIERS IN PLANT SCIENCE 2017; 8:2116. [PMID: 29312382 PMCID: PMC5735124 DOI: 10.3389/fpls.2017.02116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 11/28/2017] [Indexed: 05/11/2023]
Abstract
There is a strong positive relationship between nuclear genome size and cell size across the eukaryotic domain, but the cause and effect of this relationship is unclear. A positive coupling of cell size and DNA content has also been recorded for various bacteria, suggesting that, with some exceptions, this association might be universal throughout the tree of life. However, the link between cell size and genome size has not yet been thoroughly explored with respect to chloroplasts, or organelles as a whole, largely because of a lack data on cell morphology and organelle DNA content. Here, I speculate about a potential positive scaling of cell size and chloroplast genome size within different plastid-bearing protists, including ulvophyte, prasinophyte, and trebouxiophyte green algae. I provide examples in which large and small chloroplast DNAs occur alongside large and small cell sizes, respectively, as well as examples where this trend does not hold. Ultimately, I argue that a relationship between cellular architecture and organelle genome architecture is worth exploring, and encourage researchers to keep an open mind on this front.
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