1
|
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.
Collapse
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.)
| |
Collapse
|
2
|
Cho HS, Lee J. Taxonomic reinvestigation of the genus Tetradesmus (Scenedesmaceae; Sphaeropleales) based on morphological characteristics and chloroplast genomes. FRONTIERS IN PLANT SCIENCE 2024; 15:1303175. [PMID: 38419779 PMCID: PMC10899504 DOI: 10.3389/fpls.2024.1303175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/19/2024] [Indexed: 03/02/2024]
Abstract
The genus Tetradesmus (Scenedesmaceae; Sphaeropleales) comprises one of the most abundant green algae in freshwater environments. It includes morphologically diverse species that exhibit bundle-like, plane-arranged coenobia, and unicells, because several different Scenedesmus-like groups were integrated into this genus based on phylogenetic analysis. Nevertheless, there is no clear information regarding the phylogenetic relationship of Tetradesmus species, determined using several marker genes, because of low phylogenetic support and insufficient molecular data. Currently, genome information is available from diverse taxa, which could provide high-resolution evolutionary relationships. In particular, phylogenetic studies using chloroplast genomes demonstrated the potential to establish high-resolution phylogenetic relationships. However, only three chloroplast genomes are available from the genus Tetradesmus. In this study, we newly generated 9 chloroplast genomes from Tetradesmus and constructed a high-resolution phylogeny using a concatenated alignment of 69 chloroplast protein sequences. We also report one novel species (T. lancea), one novel variety (T. obliquus var. spiraformis), and two novel formae (T. dissociatus f. oviformis, T. obliquus f. rectilineare) within the genus Tetradesmus based on morphological characteristics (e.g., cellular arrangements and coenobial types) and genomic features (e.g., different exon-intron structures in chloroplast genomes). Moreover, we taxonomically reinvestigated the genus Tetradesmus based on these results. Altogether, our study can provide a comprehensive understanding of the taxonomic approaches for investigating this genus.
Collapse
Affiliation(s)
- Hyeon Shik Cho
- Department of Oceanography, Kyungpook National University, Daegu, Republic of Korea
| | - JunMo Lee
- Department of Oceanography, Kyungpook National University, Daegu, Republic of Korea
- Kyungpook Institute of Oceanography, Kyungpook National University, Daegu, Republic of Korea
| |
Collapse
|
3
|
Brito JBP, Antunes AM, Ferreira RDSB, de Campos Telles MP, Targueta CP, Soares TN. Complete Chloroplast Genomes of Pterodon emarginatus Vogel and Pterodon pubescens Benth: Comparative and Phylogenetic Analyses. Curr Genomics 2023; 24:236-249. [PMID: 38169762 PMCID: PMC10758126 DOI: 10.2174/0113892029244147231016050434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/03/2023] [Accepted: 07/17/2023] [Indexed: 01/05/2024] Open
Abstract
Background The species Pterodon emarginatus and P. pubescens, popularly known as white sucupira or faveira, are native to the Cerrado biome and have the potential for medicinal use and reforestation. They are sister species with evolutionary proximity. Objective Considering that the chloroplast genome exhibits a conserved structure and genes, the analysis of its sequences can contribute to the understanding of evolutionary, phylogenetic, and diversity issues. Methods The chloroplast genomes of P. emarginatus and P. pubescens were sequenced on the Illumina MiSeq platform. The genomes were assembled based on the de novo strategy. We performed the annotation of the genes and the repetitive regions of the genomes. The nucleotide diversity and phylogenetic relationships were analyzed using the gene sequences of these species and others of the Leguminosae family, whose genomes are available in databases. Results The complete chloroplast genome of P. emarginatus is 159,877 bp, and that of P. pubescens is 159,873 bp. The genomes of both species have circular and quadripartite structures. A total of 127 genes were predicted in both species, including 110 single-copy genes and 17 duplicated genes in the inverted regions. 141 microsatellite regions were identified in P. emarginatus and 140 in P. pubescens. The nucleotide diversity estimates of the gene regions in twenty-one species of the Leguminosae family were 0.062 in LSC, 0.086 in SSC, and 0.036 in IR. The phylogenetic analysis demonstrated the proximity between the genera Pterodon and Dipteryx, both from the clade Dipterygeae. Ten pairs of primers with potential for the development of molecular markers were designed. Conclusion The genetic information obtained on the chloroplast genomes of P. emarginatus and P. pubescens presented here reinforces the similarity and evolutionary proximity between these species, with a similarity percentage of 99.8%.
Collapse
Affiliation(s)
- Juliana Borges Pereira Brito
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
- Postgraduate Program in Genetics and Plant Breeding, School of Agronomy, Federal University of Goiás, Goiânia, Goiás , Brazil
| | - Adriana Maria Antunes
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
- Postgraduate Program in Genetics and Plant Breeding, School of Agronomy, Federal University of Goiás, Goiânia, Goiás , Brazil
| | - Ramilla dos Santos Braga Ferreira
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
| | - Mariana Pires de Campos Telles
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
- School of Medical and Life Sciences, Pontifical Catholic University of Goiás, Goiânia, Goiás, CEP: 74605-010 Brazil
| | - Cintia Pelegrineti Targueta
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
| | - Thannya Nascimento Soares
- Laboratory of Genetics and Biodiversity, Institute of Biological Sciences, Federal University of Goiás, Goiânia, Goiás, CEP: 74001-970 Brazil
- Postgraduate Program in Genetics and Plant Breeding, School of Agronomy, Federal University of Goiás, Goiânia, Goiás , Brazil
| |
Collapse
|
4
|
Barcytė D, Eliáš M. Hydrocytium expands the phylogenetic, morphological, and genomic diversity of the poorly known green algal order Chaetopeltidales. AMERICAN JOURNAL OF BOTANY 2023; 110:e16238. [PMID: 37661934 DOI: 10.1002/ajb2.16238] [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: 06/17/2023] [Revised: 08/17/2023] [Accepted: 08/17/2023] [Indexed: 09/05/2023]
Abstract
PREMISE Chaetopeltidales is a small, understudied order of the green algal class Chlorophyceae, that is slowly expanding with the occasional discoveries of novel algae. Here we demonstrate that hitherto unrecognized chaetopeltidaleans also exist among previously described but neglected and misclassified species. METHODS Strain SAG 40.91 of Characium acuminatum, shown by previous preliminary evidence to have affinities with the orders Oedogoniales, Chaetophorales, and Chaetopeltidales (together constituting the OCC clade), was investigated with light and electron microscopy to characterize its morphology and ultrastructure. Sequence assemblies of the organellar and nuclear genomes were obtained and utilized in bioinformatic and phylogenetic analyses to address the phylogenetic position of the alga and its salient genomic features. RESULTS The characterization of strain SAG 40.91 and a critical literature review led us to reinstate the forgotten genus Hydrocytium A.Braun 1855, with SAG 40.91 representing its type species, Hydrocytium acuminatum. Independent molecular markers converged on placing H. acuminatum as a deeply diverged lineage of the order Chaetopeltidales, formalized as the new family Hydrocytiaceae. Both chloroplast and mitochondrial genomes shared characteristics with other members of Chaetopeltidales and were bloated by repetitive sequences. Notably, the mitochondrial cox2a gene was transferred into the nuclear genome in the H. acuminatum lineage, independently of the same event in Volvocales. The nuclear genome data from H. acuminatum and from another chaetopeltidalean that was reported by others revealed endogenized viral sequences corresponding to novel members of the phylum Nucleocytoviricota. CONCLUSIONS The resurrected genus Hydrocytium expands the known diversity of chaetopeltidalean algae and provides the first glimpse into their virosphere.
Collapse
Affiliation(s)
- Dovilė Barcytė
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, Ostrava, 710 00, Czech Republic
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, Ostrava, 710 00, Czech Republic
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Liu BW, Li SY, Yan QF, Zhu H, Liu GX. Seven newly sequenced chloroplast genomes from the order Watanabeales (Trebouxiophyceae, Chlorophyta): Phylogenetic and comparative analysis. Gene 2023; 863:147287. [PMID: 36804852 DOI: 10.1016/j.gene.2023.147287] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/21/2022] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
The little-known order Watanabeales currently includes 10 genera with Chlorella-like species that reproduce by unequal-sized autospores and are predominantly solitary or terrestrial. The taxonomic scheme of Watanabeales has only been primarily inferred by short and less informative rDNA phylogenetic analysis. In the present study, seven newly sequenced genomes and one reported chloroplast genome representing the existing major branches of Watanabeales were harvested to phylogenetically reconstruct this order and to further understand its evolution. All chloroplast genomes of Watanabeales ranging from 133 to 274 kb were circular mapping and lacked a quadripartite structure. The chloroplast genome size, GC content, number of introns, and length of intergenic region proportion of the Watanabeales showed consistent trends, with Calidiella yingdensis D201 and Kalinella pachyderma 2601 having the lowest and highest values, respectively, echoing the positive correlation between organismal size and genome size. Phylogenetic analysis of Watanabeales based on 76 protein-coding genes coupled with the establishment of various complex analytical methods determined the unique robust taxonomic scheme which was incongruent with rDNA. Comparative genomic analyses revealed that the chloroplast genomes of Watanabeales accounted for numerous complex rearrangements and inversions which indicated high cryptic diversity. Substitution rate estimation indicated that the chloroplast genomes of Watanabeales were under purifying selection and similar evolutionary pressure and supported the view that genus Symbiochloris should be excluded from Watanabeales. Our results enrich the chloroplast genome resources of Watanabeales, clarify the phylogenetic status of species within this order, and provide more reference information for subsequent taxonomic and phylogenetic study.
Collapse
Affiliation(s)
- Ben-Wen Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Shu-Yin Li
- Yangtze River Basin Ecological Environment Monitoring and Scientific Research Center, Yangtze River Basin Ecological Environment Supervision and Administration Bureau, Ministry of Ecological Environment, Wuhan 430072, China
| | - Qiu-Feng Yan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Huan Zhu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Guo-Xiang Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| |
Collapse
|
7
|
Hoffman JR, Karol KG, Ohmura Y, Pogoda CS, Keepers KG, McMullin RT, Lendemer JC. Mitochondrial genomes in the iconic reindeer lichens: Architecture, variation, and synteny across multiple evolutionary scales. Mycologia 2023; 115:187-205. [PMID: 36736327 DOI: 10.1080/00275514.2022.2157665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Variation in mitochondrial genome composition across intraspecific, interspecific, and higher taxonomic scales has been little studied in lichen obligate symbioses. Cladonia is one of the most diverse and ecologically important lichen genera, with over 500 species representing an array of unique morphologies and chemical profiles. Here, we assess mitochondrial genome diversity and variation in this flagship genus, with focused sampling of two clades of the "true" reindeer lichens, Cladonia subgenus Cladina, and additional genomes from nine outgroup taxa. We describe composition and architecture at the gene and the genome scale, examining patterns in organellar genome size in larger taxonomic groups in Ascomycota. Mitochondrial genomes of Cladonia, Pilophorus, and Stereocaulon were consistently larger than those of Lepraria and contained more introns, suggesting a selective pressure in asexual morphology in Lepraria driving it toward genomic simplification. Collectively, lichen mitochondrial genomes were larger than most other fungal life strategies, reaffirming the notion that coevolutionary streamlining does not correlate to genome size reductions. Genomes from Cladonia ravenelii and Stereocaulon pileatum exhibited ATP9 duplication, bearing paralogs that may still be functional. Homing endonuclease genes (HEGs), though scarce in Lepraria, were diverse and abundant in Cladonia, exhibiting variable evolutionary histories that were sometimes independent of the mitochondrial evolutionary history. Intraspecific HEG diversity was also high, with C. rangiferina especially bearing a range of HEGs with one unique to the species. This study reveals a rich history of events that have transformed mitochondrial genomes of Cladonia and related genera, allowing future study alongside a wealth of assembled genomes.
Collapse
Affiliation(s)
- Jordan R Hoffman
- Department of Biology, The City University of New York Graduate Center, 365 5th Avenue, New York, New York 10016
- Institute of Systemic Botany, The New York Botanical Garden, Bronx, New York 10458-5126
| | - Kenneth G Karol
- Institute of Systemic Botany, The New York Botanical Garden, Bronx, New York 10458-5126
| | - Yoshihito Ohmura
- Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan
| | - Cloe S Pogoda
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309
| | - Kyle G Keepers
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309
| | - Richard T McMullin
- Research and Collections, Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada
| | - James C Lendemer
- Institute of Systemic Botany, The New York Botanical Garden, Bronx, New York 10458-5126
| |
Collapse
|
8
|
Wang L, Zhang S, Fang J, Jin X, Mamut R, Li P. The Chloroplast Genome of the Lichen Photobiont Trebouxiophyceae sp. DW1 and Its Phylogenetic Implications. Genes (Basel) 2022; 13:genes13101840. [PMID: 36292725 PMCID: PMC9601494 DOI: 10.3390/genes13101840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/30/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022] Open
Abstract
Lichens are symbiotic associations of algae and fungi. The genetic mechanism of the symbiosis of lichens and the influence of symbiosis on the size and composition of the genomes of symbiotic algae have always been intriguing scientific questions explored by lichenologists. However, there were limited data on lichen genomes. Therefore, we isolated and purified a lichen symbiotic alga to obtain a single strain (Trebouxiophyceae sp. DW1), and then obtained its chloroplast genome information by next-generation sequencing (NGS). The chloroplast genome is 129,447 bp in length, and the GC content is 35.2%. Repetitive sequences with the length of 30–35 bp account for 1.27% of the total chloroplast genome. The simple sequence repeats are all mononucleotide repeats. Codon usage analysis showed that the genome tended to use codon ending in A/U. By comparing the length of different regions of Trebouxiophyceae genomes, we found that the changes in the length of exons, introns, and intergenic sequences affect the size of genomes. Trebouxiophyceae had an unstable chloroplast genome structure, with IRs repeatedly losing during evolution. Phylogenetic analysis showed that Trebouxiophyceae is paraphyletic, and Trebouxiophyceae sp. DW1 is sister to the clade of Koliella longiseta and Pabia signiensis.
Collapse
Affiliation(s)
- Lidan Wang
- College of Life Sciences and Technology, Xinjiang University, Urumchi 830046, China
| | - Shenglu Zhang
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jinjin Fang
- College of Life Sciences and Technology, Xinjiang University, Urumchi 830046, China
| | - Xinjie Jin
- College of Life and Environmental Science, Wenzhou University, Wenzhou 325035, China
| | - Reyim Mamut
- College of Life Sciences and Technology, Xinjiang University, Urumchi 830046, China
- Correspondence: (R.M.); (P.L.)
| | - Pan Li
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Correspondence: (R.M.); (P.L.)
| |
Collapse
|
9
|
Robison T, Nelson JM, Hauser DA, Lewis LA, Li FW. Dynamic plastid and mitochondrial genomes in Chaetopeltidales (Chlorophyceae) and characterization of a new chlorophyte taxon. AMERICAN JOURNAL OF BOTANY 2022; 109:939-951. [PMID: 35678538 DOI: 10.1002/ajb2.16015] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 06/15/2023]
Abstract
PREMISE Chaetopeltidales is a poorly characterized order in the Chlorophyceae, with only two plastid and no mitochondrial genomes published. Here we describe a new taxon in Chaetopeltidales, Gormaniella terricola gen. et sp. nov. and characterize both of its organellar genomes. METHODS Gormaniella terricola was inadvertently isolated from a surface-sterilized hornwort thallus. Light microscopy was used to characterize its vegetative morphology. Organellar genomes were assembled, annotated, and analyzed using a variety of software packages. RESULTS The mitochondrial genome (66,927 bp) represents the first complete mitochondrial genome published for Chaetopeltidales. The chloroplast genome, measuring 428,981 bp, is one of the largest plastid genomes published to date and shares this large size and an incredible number of short, dispersed repeats with the other sequenced chloroplast genomes in Chaetopeltidales. Despite these shared features, the chloroplast genomes of Chaetopeltidales appear to be highly rearranged when compared to one another, with numerous inversions, translocations, and duplications, suggesting a particularly dynamic chloroplast genome. Both the chloroplast and mitochondrial genomes of G. terricola contain a number of mobile group I and group II introns, which appear to have invaded separately. Three of the introns within the mitochondrial genome encode homing endonucleases that are phylogenetically nested within those found in fungi, rather than algae, suggesting a possible case of horizontal gene transfer. CONCLUSIONS These results help to shed light on a poorly understood group of algae and their unusual organellar genomes, raising additional questions about the unique patterns of genome evolution within Chaetopeltidales.
Collapse
Affiliation(s)
- Tanner Robison
- Plant Biology Section, Cornell University, Ithaca, NY, USA
- Boyce Thompson Institute, Ithaca, NY, USA
| | | | | | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
| | - Fay-Wei Li
- Plant Biology Section, Cornell University, Ithaca, NY, USA
- Boyce Thompson Institute, Ithaca, NY, USA
| |
Collapse
|
10
|
Park SH, Kyndt JA, Brown JK. Comparison of Auxenochlorella protothecoides and Chlorella spp. Chloroplast Genomes: Evidence for Endosymbiosis and Horizontal Virus-like Gene Transfer. Life (Basel) 2022; 12:life12030458. [PMID: 35330209 PMCID: PMC8955559 DOI: 10.3390/life12030458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 12/02/2022] Open
Abstract
Resequencing of the chloroplast genome (cpDNA) of Auxenochlorella protothecoides UTEX 25 was completed (GenBank Accession no. KC631634.1), revealing a genome size of 84,576 base pairs and 30.8% GC content, consistent with features reported for the previously sequenced A. protothecoides 0710, (GenBank Accession no. KC843975). The A. protothecoides UTEX 25 cpDNA encoded 78 predicted open reading frames, 32 tRNAs, and 4 rRNAs, making it smaller and more compact than the cpDNA genome of C. variabilis (124,579 bp) and C. vulgaris (150,613 bp). By comparison, the compact genome size of A. protothecoides was attributable primarily to a lower intergenic sequence content. The cpDNA coding regions of all known Chlorella species were found to be organized in conserved colinear blocks, with some rearrangements. The Auxenochlorella and Chlorella species genome structure and composition were similar, and of particular interest were genes influencing photosynthetic efficiency, i.e., chlorophyll synthesis and photosystem subunit I and II genes, consistent with other biofuel species of interest. Phylogenetic analysis revealed that Prototheca cutis is the closest known A. protothecoides relative, followed by members of the genus Chlorella. The cpDNA of A. protothecoides encodes 37 genes that are highly homologous to representative cyanobacteria species, including rrn16, rrn23, and psbA, corroborating a well-recognized symbiosis. Several putative coding regions were identified that shared high nucleotide sequence identity with virus-like sequences, suggestive of horizontal gene transfer. Despite these predictions, no corresponding transcripts were obtained by RT-PCR amplification, indicating they are unlikely to be expressed in the extant lineage.
Collapse
Affiliation(s)
- Sang-Hyuck Park
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA; (S.-H.P.); (J.K.B.)
- Institute of Cannabis Research, Colorado State University-Pueblo, Pueblo, CO 81001, USA
| | - John A. Kyndt
- College of Science and Technology, Bellevue University, Bellevue, NE 68005, USA
- Correspondence:
| | - Judith K. Brown
- School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA; (S.-H.P.); (J.K.B.)
| |
Collapse
|
11
|
Yang T, Sahu SK, Yang L, Liu Y, Mu W, Liu X, Strube ML, Liu H, Zhong B. Comparative Analyses of 3,654 Plastid Genomes Unravel Insights Into Evolutionary Dynamics and Phylogenetic Discordance of Green Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:808156. [PMID: 35498716 PMCID: PMC9038950 DOI: 10.3389/fpls.2022.808156] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/07/2022] [Indexed: 05/03/2023]
Abstract
The plastid organelle is essential for many vital cellular processes and the growth and development of plants. The availability of a large number of complete plastid genomes could be effectively utilized to understand the evolution of the plastid genomes and phylogenetic relationships among plants. We comprehensively analyzed the plastid genomes of Viridiplantae comprising 3,654 taxa from 298 families and 111 orders and compared the genomic organizations in their plastid genomic DNA among major clades, which include gene gain/loss, gene copy number, GC content, and gene blocks. We discovered that some important genes that exhibit similar functions likely formed gene blocks, such as the psb family presumably showing co-occurrence and forming gene blocks in Viridiplantae. The inverted repeats (IRs) in plastid genomes have doubled in size across land plants, and their GC content is substantially higher than non-IR genes. By employing three different data sets [all nucleotide positions (nt123), only the first and second codon positions (nt12), and amino acids (AA)], our phylogenomic analyses revealed Chlorokybales + Mesostigmatales as the earliest-branching lineage of streptophytes. Hornworts, mosses, and liverworts forming a monophylum were identified as the sister lineage of tracheophytes. Based on nt12 and AA data sets, monocots, Chloranthales and magnoliids are successive sister lineages to the eudicots + Ceratophyllales clade. The comprehensive taxon sampling and analysis of different data sets from plastid genomes recovered well-supported relationships of green plants, thereby contributing to resolving some long-standing uncertainties in the plant phylogeny.
Collapse
Affiliation(s)
- Ting Yang
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Sunil Kumar Sahu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- *Correspondence: Sunil Kumar Sahu,
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yang Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Weixue Mu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Xin Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Mikael Lenz Strube
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Huan Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Bojian Zhong,
| |
Collapse
|
12
|
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.
Collapse
|
13
|
Yu Y, Ouyang Z, Guo J, Zeng W, Zhao Y, Huang L. Complete Chloroplast Genome Sequence of Erigeron breviscapus and Characterization of Chloroplast Regulatory Elements. FRONTIERS IN PLANT SCIENCE 2021; 12:758290. [PMID: 34899783 PMCID: PMC8657942 DOI: 10.3389/fpls.2021.758290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/20/2021] [Indexed: 06/14/2023]
Abstract
Erigeron breviscapus is a famous medicinal plant. However, the limited chloroplast genome information of E. breviscapus, especially for the chloroplast DNA sequence resources, has hindered the study of E. breviscapus chloroplast genome transformation. Here, the complete chloroplast (cp) genome of E. breviscapus was reported. This genome was 152,164bp in length, included 37.2% GC content and was structurally arranged into two 24,699bp inverted repeats (IRs) and two single-copy areas. The sizes of the large single-copy region and the small single-copy region were 84,657 and 18,109bp, respectively. The E. breviscapus cp genome consisted of 127 coding genes, including 83 protein coding genes, 36 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. For those genes, 95 genes were single copy genes and 16 genes were duplicated in two inverted regions with seven tRNAs, four rRNAs, and five protein coding genes. Then, genomic DNA of E. breviscapus was used as a template, and the endogenous 5' and 3' flanking sequences of the trnI gene and trnA gene were selected as homologous recombinant fragments in vector construction and cloned through PCR. The endogenous 5' flanking sequences of the psbA gene and rrn16S gene, the endogenous 3' flanking sequences of the psbA gene, rbcL gene, and rps16 gene and one sequence element from the psbN-psbH chloroplast operon were cloned, and certain chloroplast regulatory elements were identified. Two homologous recombination fragments and all of these elements were constructed into the cloning vector pBluescript SK (+) to yield a series of chloroplast expression vectors, which harbored the reporter gene EGFP and the selectable marker aadA gene. After identification, the chloroplast expression vectors were transformed into Escherichia coli and the function of predicted regulatory elements was confirmed by a spectinomycin resistance test and fluorescence intensity measurement. The results indicated that aadA gene and EGFP gene were efficiently expressed under the regulation of predicted regulatory elements and the chloroplast expression vector had been successfully constructed, thereby providing a solid foundation for establishing subsequent E. breviscapus chloroplast transformation system and genetic improvement of E. breviscapus.
Collapse
Affiliation(s)
- Yifan Yu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhen Ouyang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Juan Guo
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Wen Zeng
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yujun Zhao
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Luqi Huang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, China
| |
Collapse
|
14
|
Ren Q, Wang YC, Lin Y, Zhen Z, Cui Y, Qin S. The extremely large chloroplast genome of the green alga Haematococcus pluvialis: Genome structure, and comparative analysis. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
15
|
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.
Collapse
|
16
|
Kück U, Schmitt O. The Chloroplast Trans-Splicing RNA-Protein Supercomplex from the Green Alga Chlamydomonas reinhardtii. Cells 2021; 10:cells10020290. [PMID: 33535503 PMCID: PMC7912774 DOI: 10.3390/cells10020290] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/27/2022] Open
Abstract
In eukaryotes, RNA trans-splicing is a significant RNA modification process for the end-to-end ligation of exons from separately transcribed primary transcripts to generate mature mRNA. So far, three different categories of RNA trans-splicing have been found in organisms within a diverse range. Here, we review trans-splicing of discontinuous group II introns, which occurs in chloroplasts and mitochondria of lower eukaryotes and plants. We discuss the origin of intronic sequences and the evolutionary relationship between chloroplast ribonucleoprotein complexes and the nuclear spliceosome. Finally, we focus on the ribonucleoprotein supercomplex involved in trans-splicing of chloroplast group II introns from the green alga Chlamydomonas reinhardtii. This complex has been well characterized genetically and biochemically, resulting in a detailed picture of the chloroplast ribonucleoprotein supercomplex. This information contributes substantially to our understanding of the function of RNA-processing machineries and might provide a blueprint for other splicing complexes involved in trans- as well as cis-splicing of organellar intron RNAs.
Collapse
|
17
|
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.
Collapse
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,
| |
Collapse
|
18
|
Chen N, Sha LN, Wang YL, Yin LJ, Zhang Y, Wang Y, Wu DD, Kang HY, Zhang HQ, Zhou YH, Sun GL, Fan X. Variation in Plastome Sizes Accompanied by Evolutionary History in Monogenomic Triticeae (Poaceae: Triticeae). FRONTIERS IN PLANT SCIENCE 2021; 12:741063. [PMID: 34966398 PMCID: PMC8710740 DOI: 10.3389/fpls.2021.741063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 11/02/2021] [Indexed: 05/17/2023]
Abstract
To investigate the pattern of chloroplast genome variation in Triticeae, we comprehensively analyzed the indels in protein-coding genes and intergenic sequence, gene loss/pseudonization, intron variation, expansion/contraction in inverted repeat regions, and the relationship between sequence characteristics and chloroplast genome size in 34 monogenomic Triticeae plants. Ancestral genome reconstruction suggests that major length variations occurred in four-stem branches of monogenomic Triticeae followed by independent changes in each genus. It was shown that the chloroplast genome sizes of monogenomic Triticeae were highly variable. The chloroplast genome of Pseudoroegneria, Dasypyrum, Lophopyrum, Thinopyrum, Eremopyrum, Agropyron, Australopyrum, and Henradia in Triticeae had evolved toward size reduction largely because of pseudogenes elimination events and length deletion fragments in intergenic. The Aegilops/Triticum complex, Taeniatherum, Secale, Crithopsis, Herteranthelium, and Hordeum in Triticeae had a larger chloroplast genome size. The large size variation in major lineages and their subclades are most likely consequences of adaptive processes since these variations were significantly correlated with divergence time and historical climatic changes. We also found that several intergenic regions, such as petN-trnC and psbE-petL containing unique genetic information, which can be used as important tools to identify the maternal relationship among Triticeae species. Our results contribute to the novel knowledge of plastid genome evolution in Triticeae.
Collapse
Affiliation(s)
- Ning Chen
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Li-Na Sha
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Yi-Ling Wang
- College of Life Science, Shanxi Normal University, Shanxi, China
| | - Ling-Juan Yin
- Lijiang Nationality Secondary Specialized School, Lijiang, China
| | - Yue Zhang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Yi Wang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Dan-Dan Wu
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Hou-Yang Kang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Hai-Qin Zhang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Yong-Hong Zhou
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Gen-Lou Sun
- Saint Mary’s University, Halifax, NS, Canada
- *Correspondence: Gen-Lou Sun,
| | - Xing Fan
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China
- Xing Fan,
| |
Collapse
|
19
|
Liu B, Hu Y, Hu Z, Liu G, Zhu H. Taxonomic scheme of the order Chaetophorales (Chlorophyceae, Chlorophyta) based on chloroplast genomes. BMC Genomics 2020; 21:442. [PMID: 32590931 PMCID: PMC7320567 DOI: 10.1186/s12864-020-06845-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/17/2020] [Indexed: 11/11/2022] Open
Abstract
Background Order Chaetophorales currently includes six families, namely Schizomeridaceae, Aphanochaetaceae, Barrancaceae, Uronemataceae, Fritschiellaceae, and Chaetophoraceae. The phylogenetic relationships of Chaetophorales have been inferred primarily based on short and less informative rDNA sequences. This study aimed to phylogenetically reconstruct order Chaetophorales and determine the taxonomic scheme, and to further understand the evolution of order Chaetophorales. Results In the present study, seven complete and five fragmentary chloroplast genomes were harvested. Phylogenomic and comparative genomic analysis were performed to determine the taxonomic scheme within Chaetophorales. Consequently, Oedogoniales was found to be a sister to a clade linking Chaetophorales and Chaetopeltidales. Schizomeriaceae, and Aphanochaetaceae clustered into a well-resolved basal clade in Chaetophorales, inconsistent with the results of phylogenetic analysis based on rDNA sequences. Comparative genomic analyses revealed that the chloroplast genomes of Schizomeriaceae and Aphanochaetaceae were highly conserved and homologous, highlighting the closest relationship in this order. Germination types of zoospores precisely correlated with the phylogenetic relationships. Conclusions chloroplast genome structure analyses, synteny analyses, and zoospore germination analyses were concurrent with phylogenetic analyses based on the chloroplast genome, and all of them robustly determined the unique taxonomic scheme of Chaetophorales and the relationships of Oedogoniales, Chaetophorales, and Chaetopeltidales.
Collapse
Affiliation(s)
- Benwen Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yuxin Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100039, China
| | - Zhengyu Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Guoxiang Liu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Huan Zhu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
| |
Collapse
|
20
|
Martínez-Alberola F, Barreno E, Casano LM, Gasulla F, Molins A, Moya P, González-Hourcade M, Del Campo EM. The chloroplast genome of the lichen-symbiont microalga Trebouxia sp. Tr9 (Trebouxiophyceae, Chlorophyta) shows short inverted repeats with a single gene and loss of the rps4 gene, which is encoded by the nucleus. JOURNAL OF PHYCOLOGY 2020; 56:170-184. [PMID: 31578712 DOI: 10.1111/jpy.12928] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/15/2019] [Indexed: 06/10/2023]
Abstract
The Trebouxiophyceae is the class of Chlorophyta algae from which the highest number of chloroplast genome (cpDNA) sequences has been obtained. Several species in this class participate in symbioses with fungi to form lichens. However, no cpDNA has been obtained from any Trebouxia lichen-symbiont microalgae, which are present in approximately half of all lichens. Here, we report the sequence of the completely assembled cpDNA from Trebouxia sp. TR9 and a comparative study with other Trebouxio-phyceae. The organization of the chloroplast genome of Trebouxia sp. TR9 has certain features that are unusual in the Trebouxiophyceae and other green algae. The most remarkable characteristics are the presence of long intergenic spacers, a quadripartite structure with short inverted repeated sequences (IRs), and the loss of the rps4 gene. The presence of long intergenic spacers accounts for a larger cpDNA size in comparison to other closely related Trebouxiophyceae. The IRs, which were thought to be lost in the Trebouxiales, are distinct from most of cpDNAs since they lack the rRNA operon and uniquely includes the rbcL gene. The functional transfer of the rps4 gene to the nuclear genome has been confirmed by sequencing and examination of the gene architecture, which includes three spliceosomal introns as well as the verification of the presence of the corresponding transcript. This is the first documented transfer of the rps4 gene from the chloroplast to the nucleus among Viridiplantae. Additionally, a fairly well-resolved phylogenetic reconstruction, including Trebouxia sp. TR9 along with other Trebouxiophyceae, was obtained based on a set of conserved chloroplast genes.
Collapse
Affiliation(s)
- Fernando Martínez-Alberola
- ICBIBE, Botánica, Facultad de Ciencias Biológicas, Universitat de València, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain
| | - Eva Barreno
- ICBIBE, Botánica, Facultad de Ciencias Biológicas, Universitat de València, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain
| | - Leonardo M Casano
- Department of Life Sciences, University of Alcalá, Alcalá de Henares, Madrid, 28805, Spain
| | - Francisco Gasulla
- Department of Life Sciences, University of Alcalá, Alcalá de Henares, Madrid, 28805, Spain
| | - Arantzazu Molins
- ICBIBE, Botánica, Facultad de Ciencias Biológicas, Universitat de València, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain
| | - Patricia Moya
- ICBIBE, Botánica, Facultad de Ciencias Biológicas, Universitat de València, Dr. Moliner 50, Burjassot, Valencia, 46100, Spain
| | | | - Eva M Del Campo
- Department of Life Sciences, University of Alcalá, Alcalá de Henares, Madrid, 28805, Spain
| |
Collapse
|
21
|
Moreira D, López-García P. Evolution: King-Size Plastid Genomes in a New Red Algal Clade. Curr Biol 2019; 27:R651-R653. [PMID: 28697364 DOI: 10.1016/j.cub.2017.05.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Plastids, the photosynthetic organelles of eukaryotes, exhibit remarkably stable genome architecture. However, a recent study of microscopic red algae has found new record-sized plastid genomes with unusual architectures. These species form a new branch in the tree of red algae.
Collapse
Affiliation(s)
- David Moreira
- Ecologie Systématique Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France.
| | - Purificación López-García
- Ecologie Systématique Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France
| |
Collapse
|
22
|
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.
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
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.
Collapse
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
| |
Collapse
|
25
|
Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
| |
Collapse
|
26
|
Next-Generation Sequencing of Haematococcus lacustris Reveals an Extremely Large 1.35-Megabase Chloroplast Genome. GENOME ANNOUNCEMENTS 2018; 6:6/12/e00181-18. [PMID: 29567741 PMCID: PMC5864939 DOI: 10.1128/genomea.00181-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Haematococcus lacustris is an industrially relevant microalga that is used for the production of the carotenoid astaxanthin. Here, we report the use of PacBio long-read sequencing to assemble the chloroplast genome of H. lacustris strain UTEX:2505. At 1.35 Mb, this is the largest assembled chloroplast of any plant or alga known to date.
Collapse
|
27
|
McManus HA, Fučíková K, Lewis PO, Lewis LA, Karol KG. Organellar phylogenomics inform systematics in the green algal family Hydrodictyaceae (Chlorophyceae) and provide clues to the complex evolutionary history of plastid genomes in the green algal tree of life. AMERICAN JOURNAL OF BOTANY 2018; 105:315-329. [PMID: 29722901 DOI: 10.1002/ajb2.1066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 12/19/2017] [Indexed: 05/11/2023]
Abstract
PREMISE OF THE STUDY Phylogenomic analyses across the green algae are resolving relationships at the class, order, and family levels and highlighting dynamic patterns of evolution in organellar genomes. Here we present a within-family phylogenomic study to resolve genera and species relationships in the family Hydrodictyaceae (Chlorophyceae), for which poor resolution in previous phylogenetic studies, along with divergent morphological traits, have precluded taxonomic revisions. METHODS Complete plastome sequences and mitochondrial protein-coding gene sequences were acquired from representatives of the Hydrodictyaceae using next-generation sequencing methods. Plastomes were characterized, and gene order and content were compared with plastomes spanning the Sphaeropleales. Single-gene and concatenated-gene phylogenetic analyses of plastid and mitochondrial genes were performed. KEY RESULTS The Hydrodictyaceae contain the largest sphaeroplealean plastomes thus far fully sequenced. Conservation of plastome gene order within Hydrodictyaceae is striking compared with more dynamic patterns revealed across Sphaeropleales. Phylogenetic analyses resolve Hydrodictyon sister to a monophyletic Pediastrum, though the morphologically distinct P. angulosum and P. duplex continue to be polyphyletic. Analyses of plastid data supported the neochloridacean genus Chlorotetraëdron as sister to Hydrodictyaceae, while conflicting signal was found in the mitochondrial data. CONCLUSIONS A phylogenomic approach resolved within-family relationships not obtainable with previous phylogenetic analyses. Denser taxon sampling across Sphaeropleales is necessary to capture patterns in plastome evolution, and further taxa and studies are needed to fully resolve the sister lineage to Hydrodictyaceae and polyphyly of Pediastrum angulosum and P. duplex.
Collapse
Affiliation(s)
- Hilary A McManus
- Department of Biological and Environmental Sciences, Le Moyne College, 1419 Salt Springs Road, Syracuse, New York, 13066, USA
| | - Karolina Fučíková
- Department of Natural Sciences, Assumption College, 500 Salisbury Street, Worcester, Massachusetts, 01609, USA
| | - Paul O Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Kenneth G Karol
- Lewis B. and Dorothy Cullman Program for Molecular Systematics, The New York Botanical Garden, 2900 Southern Boulevard, Bronx, New York, 10458, USA
| |
Collapse
|
28
|
Del Cortona A, Leliaert F, Bogaert KA, Turmel M, Boedeker C, Janouškovec J, Lopez-Bautista JM, Verbruggen H, Vandepoele K, De Clerck O. The Plastid Genome in Cladophorales Green Algae Is Encoded by Hairpin Chromosomes. Curr Biol 2017; 27:3771-3782.e6. [PMID: 29199074 DOI: 10.1016/j.cub.2017.11.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/30/2017] [Accepted: 11/01/2017] [Indexed: 12/28/2022]
Abstract
Virtually all plastid (chloroplast) genomes are circular double-stranded DNA molecules, typically between 100 and 200 kb in size and encoding circa 80-250 genes. Exceptions to this universal plastid genome architecture are very few and include the dinoflagellates, where genes are located on DNA minicircles. Here we report on the highly deviant chloroplast genome of Cladophorales green algae, which is entirely fragmented into hairpin chromosomes. Short- and long-read high-throughput sequencing of DNA and RNA demonstrated that the chloroplast genes of Boodlea composita are encoded on 1- to 7-kb DNA contigs with an exceptionally high GC content, each containing a long inverted repeat with one or two protein-coding genes and conserved non-coding regions putatively involved in replication and/or expression. We propose that these contigs correspond to linear single-stranded DNA molecules that fold onto themselves to form hairpin chromosomes. The Boodlea chloroplast genes are highly divergent from their corresponding orthologs, and display an alternative genetic code. The origin of this highly deviant chloroplast genome most likely occurred before the emergence of the Cladophorales, and coincided with an elevated transfer of chloroplast genes to the nucleus. A chloroplast genome that is composed only of linear DNA molecules is unprecedented among eukaryotes, and highlights unexpected variation in plastid genome architecture.
Collapse
Affiliation(s)
- Andrea Del Cortona
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium; VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Zwijnaarde, Belgium; Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium
| | - Frederik Leliaert
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium; Botanic Garden Meise, Nieuwelaan 38, 1860 Meise, Belgium
| | - Kenny A Bogaert
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium
| | - Monique Turmel
- Institut de Biologie Intégrative et des Systèmes, Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, Pavillon Charles-Eugène-Marchand 1030, Avenue de la Médecine, Québec City, QC G1V 0A6, Canada
| | - Christian Boedeker
- School of Biological Sciences, Victoria University of Wellington, New Kirk Building, Kelburn Parade, P.O. Box 600, Wellington 6012, New Zealand
| | - Jan Janouškovec
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Juan M Lopez-Bautista
- Department of Biological Sciences, The University of Alabama, 300 Hackberry Lane, Tuscaloosa, AL 35484-0345, USA
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Professors Walk, Melbourne, VIC 3010, Australia
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium; VIB Center for Plant Systems Biology, Technologiepark 927, 9052 Zwijnaarde, Belgium; Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, 9052 Zwijnaarde, Belgium
| | - Olivier De Clerck
- Department of Biology, Phycology Research Group, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium.
| |
Collapse
|
29
|
Twyford AD, Ness RW. Strategies for complete plastid genome sequencing. Mol Ecol Resour 2017; 17:858-868. [PMID: 27790830 PMCID: PMC6849563 DOI: 10.1111/1755-0998.12626] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/14/2016] [Accepted: 10/21/2016] [Indexed: 12/01/2022]
Abstract
Plastid sequencing is an essential tool in the study of plant evolution. This high-copy organelle is one of the most technically accessible regions of the genome, and its sequence conservation makes it a valuable region for comparative genome evolution, phylogenetic analysis and population studies. Here, we discuss recent innovations and approaches for de novo plastid assembly that harness genomic tools. We focus on technical developments including low-cost sequence library preparation approaches for genome skimming, enrichment via hybrid baits and methylation-sensitive capture, sequence platforms with higher read outputs and longer read lengths, and automated tools for assembly. These developments allow for a much more streamlined assembly than via conventional short-range PCR. Although newer methods make complete plastid sequencing possible for any land plant or green alga, there are still challenges for producing finished plastomes particularly from herbarium material or from structurally divergent plastids such as those of parasitic plants.
Collapse
Affiliation(s)
- Alex D. Twyford
- Institute of Evolutionary BiologyAshworth LaboratoriesUniversity of EdinburghEdinburghEH9 3FLUK
| | - Rob W. Ness
- Department of BiologyUniversity of Toronto MississaugaMississaugaONCanada
| |
Collapse
|
30
|
Carvalho EL, Wallau GL, Rangel DL, Machado LC, Pereira AB, Victoria FDC, Boldo JT, Pinto PM. Phylogenetic positioning of the Antarctic alga Prasiola crispa (Trebouxiophyceae) using organellar genomes and their structural analysis. JOURNAL OF PHYCOLOGY 2017; 53:908-915. [PMID: 28394430 DOI: 10.1111/jpy.12541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 01/09/2017] [Indexed: 06/07/2023]
Abstract
Antarctica is one of the most difficult habitats for sustaining life on earth; organisms that live there have developed different strategies for survival. Among these organisms is the green alga Prasiola crispa, belonging to the class Trebouxiophyceae. The literature on P. crispa taxonomy is scarce, and many gaps in the evolutionary relationship with its closest relatives remain. The goal of this study was to analyze the evolutionary relationships between P. crispa and other green algae using plastid and mitochondrial genomes. In addition, we analyzed the synteny conservation of these genomes of P. crispa with those of closely related species. Based on the plastid genome, P. crispa grouped with Prasiolopsis sp. SAG 84.81, another Trebouxiophyceaen species from the Prasiola clade. Based on the mitochondrial genome analysis, P. crispa grouped with other Trebouxiophyceaen species but had a basal position. The structure of the P. crispa chloroplast genome had low synteny with Prasiolopsis sp. SAG 84.81, despite some conserved gene blocks. The same was observed in the mitochondrial genome compared with Coccomyxa subellipsoidea C-169. We were able to establish the phylogenetic position of P. crispa with other species of Trebouxiophyceae using its genomes. In addition, we described the plasticity of these genomes using a structural analysis. The plastid and mitochondrial genomes of P. crispa will be useful for further genetic studies, phylogenetic analysis and resource protection of P. crispa as well as for further phylogenetic analysis of Trebouxiophyceaen green algae.
Collapse
Affiliation(s)
- Evelise Leis Carvalho
- Applied Proteomics Laboratory, University of Pampa, São Gabriel, RS, 97300-000, Brazil
| | - Gabriel Luz Wallau
- Departamento de Entomologia Centro de Pesquisas Aggeu Magalhães, Fiocruz, Recife, 50740-465, Brazil
| | - Darlene Lopes Rangel
- Applied Proteomics Laboratory, University of Pampa, São Gabriel, RS, 97300-000, Brazil
| | - Laís Ceschini Machado
- Applied Proteomics Laboratory, University of Pampa, São Gabriel, RS, 97300-000, Brazil
| | | | | | | | - Paulo Marcos Pinto
- Applied Proteomics Laboratory, University of Pampa, São Gabriel, RS, 97300-000, Brazil
| |
Collapse
|
31
|
Muñoz-Gómez SA, Mejía-Franco FG, Durnin K, Colp M, Grisdale CJ, Archibald JM, Slamovits CH. The New Red Algal Subphylum Proteorhodophytina Comprises the Largest and Most Divergent Plastid Genomes Known. Curr Biol 2017; 27:1677-1684.e4. [DOI: 10.1016/j.cub.2017.04.054] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 12/25/2022]
|
32
|
Turmel M, Otis C, Lemieux C. Divergent copies of the large inverted repeat in the chloroplast genomes of ulvophycean green algae. Sci Rep 2017; 7:994. [PMID: 28428552 PMCID: PMC5430533 DOI: 10.1038/s41598-017-01144-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/27/2017] [Indexed: 12/16/2022] Open
Abstract
The chloroplast genomes of many algae and almost all land plants carry two identical copies of a large inverted repeat (IR) sequence that can pair for flip-flop recombination and undergo expansion/contraction. Although the IR has been lost multiple times during the evolution of the green algae, the underlying mechanisms are still largely unknown. A recent comparison of IR-lacking and IR-containing chloroplast genomes of chlorophytes from the Ulvophyceae (Ulotrichales) suggested that differential elimination of genes from the IR copies might lead to IR loss. To gain deeper insights into the evolutionary history of the chloroplast genome in the Ulvophyceae, we analyzed the genomes of Ignatius tetrasporus and Pseudocharacium americanum (Ignatiales, an order not previously sampled), Dangemannia microcystis (Oltmannsiellopsidales), Pseudoneochloris marina (Ulvales) and also Chamaetrichon capsulatum and Trichosarcina mucosa (Ulotrichales). Our comparison of these six chloroplast genomes with those previously reported for nine ulvophyceans revealed unsuspected variability. All newly examined genomes feature an IR, but remarkably, the copies of the IR present in the Ignatiales, Pseudoneochloris, and Chamaetrichon diverge in sequence, with the tRNA genes from the rRNA operon missing in one IR copy. The implications of this unprecedented finding for the mechanism of IR loss and flip-flop recombination are discussed.
Collapse
Affiliation(s)
- Monique Turmel
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec (QC), Canada
| | - Christian Otis
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec (QC), Canada
| | - Claude Lemieux
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec (QC), Canada.
| |
Collapse
|
33
|
Satjarak A, Graham LE. Comparative DNA sequence analyses of Pyramimonas parkeae (Prasinophyceae) chloroplast genomes. JOURNAL OF PHYCOLOGY 2017; 53:415-424. [PMID: 28130930 DOI: 10.1111/jpy.12515] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
Prasinophytes form a paraphyletic assemblage of early diverging green algae, which have the potential to reveal the traits of the last common ancestor of the main two green lineages: (i) chlorophyte algae and (ii) streptophyte algae. Understanding the genetic composition of prasinophyte algae is fundamental to understanding the diversification and evolutionary processes that may have occurred in both green lineages. In this study, we sequenced the chloroplast genome of Pyramimonas parkeae NIES254 and compared it with that of P. parkeae CCMP726, the only other fully sequenced P. parkeae chloroplast genome. The results revealed that P. parkeae chloroplast genomes are surprisingly variable. The chloroplast genome of NIES254 was larger than that of CCMP726 by 3,204 bp, the NIES254 large single copy was 288 bp longer, the small single copy was 5,088 bp longer, and the IR was 1,086 bp shorter than that of CCMP726. Similarity values of the two strains were almost zero in four large hot spot regions. Finally, the strains differed in copy number for three protein-coding genes: ycf20, psaC, and ndhE. Phylogenetic analyses using 16S and 18S rDNA and rbcL sequences resolved a clade consisting of these two P. parkeae strains and a clade consisting of these plus other Pyramimonas isolates. These results are consistent with past studies indicating that prasinophyte chloroplast genomes display a higher level of variation than is commonly found among land plants. Consequently, prasinophyte chloroplast genomes may be less useful for inferring the early history of Viridiplantae than has been the case for land plant diversification.
Collapse
Affiliation(s)
- Anchittha Satjarak
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, Wisconsin, USA
| | - Linda E Graham
- Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, Wisconsin, USA
| |
Collapse
|
34
|
Figueroa-Martinez F, Nedelcu AM, Smith DR, Reyes-Prieto A. The Plastid Genome of Polytoma uvella Is the Largest Known among Colorless Algae and Plants and Reflects Contrasting Evolutionary Paths to Nonphotosynthetic Lifestyles. PLANT PHYSIOLOGY 2017; 173:932-943. [PMID: 27932420 PMCID: PMC5291040 DOI: 10.1104/pp.16.01628] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 12/07/2016] [Indexed: 05/11/2023]
Abstract
The loss of photosynthesis is frequently associated with parasitic or pathogenic lifestyles, but it also can occur in free-living, plastid-bearing lineages. A common consequence of becoming nonphotosynthetic is the reduction in size and gene content of the plastid genome. In exceptional circumstances, it can even result in the complete loss of the plastid DNA (ptDNA) and its associated gene expression system, as reported recently in several lineages, including the nonphotosynthetic green algal genus Polytomella Closely related to Polytomella is the polyphyletic genus Polytoma, the members of which lost photosynthesis independently of Polytomella Species from both genera are free-living organisms that contain nonphotosynthetic plastids, but unlike Polytomella, Polytoma members have retained a genome in their colorless plastid. Here, we present the plastid genome of Polytoma uvella: to our knowledge, the first report of ptDNA from a nonphotosynthetic chlamydomonadalean alga. The P. uvella ptDNA contains 25 protein-coding genes, most of which are related to gene expression and none are connected to photosynthesis. However, despite its reduced coding capacity, the P. uvella ptDNA is inflated with short repeats and is tens of kilobases larger than the ptDNAs of its closest known photosynthetic relatives, Chlamydomonas leiostraca and Chlamydomonas applanata In fact, at approximately 230 kb, the ptDNA of P. uvella represents the largest plastid genome currently reported from a nonphotosynthetic alga or plant. Overall, the P. uvella and Polytomella plastid genomes reveal two very different evolutionary paths following the loss of photosynthesis: expansion and complete deletion, respectively. We hypothesize that recombination-based DNA-repair mechanisms are at least partially responsible for the different evolutionary outcomes observed in such closely related nonphotosynthetic algae.
Collapse
Affiliation(s)
- Francisco Figueroa-Martinez
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (F.F.-M., A.M.N., A.R.-P.)
- Consejo Nacional de Ciencia y Tecnología-Universidad Autónoma Metropolitana, Vicentina, Mexico City 0934, Mexico (F.F.-M.)
- Biology Department, University of Western Ontario, London, Ontario, Canada N6A 5B7 (D.R.S.); and
- Integrated Microbiology Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8 (A.R.-P.)
| | - Aurora M Nedelcu
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (F.F.-M., A.M.N., A.R.-P.)
- Consejo Nacional de Ciencia y Tecnología-Universidad Autónoma Metropolitana, Vicentina, Mexico City 0934, Mexico (F.F.-M.)
- Biology Department, University of Western Ontario, London, Ontario, Canada N6A 5B7 (D.R.S.); and
- Integrated Microbiology Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8 (A.R.-P.)
| | - David R Smith
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (F.F.-M., A.M.N., A.R.-P.);
- Consejo Nacional de Ciencia y Tecnología-Universidad Autónoma Metropolitana, Vicentina, Mexico City 0934, Mexico (F.F.-M.);
- Biology Department, University of Western Ontario, London, Ontario, Canada N6A 5B7 (D.R.S.); and
- Integrated Microbiology Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8 (A.R.-P.)
| | - Adrian Reyes-Prieto
- Department of Biology, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (F.F.-M., A.M.N., A.R.-P.);
- Consejo Nacional de Ciencia y Tecnología-Universidad Autónoma Metropolitana, Vicentina, Mexico City 0934, Mexico (F.F.-M.);
- Biology Department, University of Western Ontario, London, Ontario, Canada N6A 5B7 (D.R.S.); and
- Integrated Microbiology Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8 (A.R.-P.)
| |
Collapse
|
35
|
Soorni A, Haak D, Zaitlin D, Bombarely A. Organelle_PBA, a pipeline for assembling chloroplast and mitochondrial genomes from PacBio DNA sequencing data. BMC Genomics 2017; 18:49. [PMID: 28061749 PMCID: PMC5219736 DOI: 10.1186/s12864-016-3412-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 12/10/2016] [Indexed: 11/18/2022] Open
Abstract
Background The development of long-read sequencing technologies, such as single-molecule real-time (SMRT) sequencing by PacBio, has produced a revolution in the sequencing of small genomes. Sequencing organelle genomes using PacBio long-read data is a cost effective, straightforward approach. Nevertheless, the availability of simple-to-use software to perform the assembly from raw reads is limited at present. Results We present Organelle-PBA, a Perl program designed specifically for the assembly of chloroplast and mitochondrial genomes. For chloroplast genomes, the program selects the chloroplast reads from a whole genome sequencing pool, maps the reads to a reference sequence from a closely related species, and then performs read correction and de novo assembly using Sprai. Organelle-PBA completes the assembly process with the additional step of scaffolding by SSPACE-LongRead. The program then detects the chloroplast inverted repeats and reassembles and re-orients the assembly based on the organelle origin of the reference. We have evaluated the performance of the software using PacBio reads from different species, read coverage, and reference genomes. Finally, we present the assembly of two novel chloroplast genomes from the species Picea glauca (Pinaceae) and Sinningia speciosa (Gesneriaceae). Conclusion Organelle-PBA is an easy-to-use Perl-based software pipeline that was written specifically to assemble mitochondrial and chloroplast genomes from whole genome PacBio reads. The program is available at https://github.com/aubombarely/Organelle_PBA. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3412-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Aboozar Soorni
- Department of Horticulture, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.,Department of Horticulture, Faculty of Horticultural Sciences and Plant Protection, University of Tehran, Karaj, 31587, Iran
| | - David Haak
- Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - David Zaitlin
- Kentucky Tobacco Research and Development Center (KTRDC), University of Kentucky, Lexington, KY, 40546, USA
| | - Aureliano Bombarely
- Department of Horticulture, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA.
| |
Collapse
|
36
|
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.
Collapse
|
37
|
Brouard JS, Turmel M, Otis C, Lemieux C. Proliferation of group II introns in the chloroplast genome of the green alga Oedocladium carolinianum (Chlorophyceae). PeerJ 2016; 4:e2627. [PMID: 27812423 PMCID: PMC5088586 DOI: 10.7717/peerj.2627] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/29/2016] [Indexed: 01/28/2023] Open
Abstract
Background The chloroplast genome sustained extensive changes in architecture during the evolution of the Chlorophyceae, a morphologically and ecologically diverse class of green algae belonging to the Chlorophyta; however, the forces driving these changes are poorly understood. The five orders recognized in the Chlorophyceae form two major clades: the CS clade consisting of the Chlamydomonadales and Sphaeropleales, and the OCC clade consisting of the Oedogoniales, Chaetophorales, and Chaetopeltidales. In the OCC clade, considerable variations in chloroplast DNA (cpDNA) structure, size, gene order, and intron content have been observed. The large inverted repeat (IR), an ancestral feature characteristic of most green plants, is present in Oedogonium cardiacum (Oedogoniales) but is lacking in the examined members of the Chaetophorales and Chaetopeltidales. Remarkably, the Oedogonium 35.5-kb IR houses genes that were putatively acquired through horizontal DNA transfer. To better understand the dynamics of chloroplast genome evolution in the Oedogoniales, we analyzed the cpDNA of a second representative of this order, Oedocladium carolinianum. Methods The Oedocladium cpDNA was sequenced and annotated. The evolutionary distances separating Oedocladium and Oedogonium cpDNAs and two other pairs of chlorophycean cpDNAs were estimated using a 61-gene data set. Phylogenetic analysis of an alignment of group IIA introns from members of the OCC clade was performed. Secondary structures and insertion sites of oedogonialean group IIA introns were analyzed. Results The 204,438-bp Oedocladium genome is 7.9 kb larger than the Oedogonium genome, but its repertoire of conserved genes is remarkably similar and gene order differs by only one reversal. Although the 23.7-kb IR is missing the putative foreign genes found in Oedogonium, it contains sequences coding for a putative phage or bacterial DNA primase and a hypothetical protein. Intergenic sequences are 1.5-fold longer and dispersed repeats are more abundant, but a smaller fraction of the Oedocladium genome is occupied by introns. Six additional group II introns are present, five of which lack ORFs and carry highly similar sequences to that of the ORF-less IIA intron shared with Oedogonium. Secondary structure analysis of the group IIA introns disclosed marked differences in the exon-binding sites; however, each intron showed perfect or nearly perfect base pairing interactions with its target site. Discussion Our results suggest that chloroplast genes rearrange more slowly in the Oedogoniales than in the Chaetophorales and raise questions as to what was the nature of the foreign coding sequences in the IR of the common ancestor of the Oedogoniales. They provide the first evidence for intragenomic proliferation of group IIA introns in the Viridiplantae, revealing that intron spread in the Oedocladium lineage likely occurred by retrohoming after sequence divergence of the exon-binding sites.
Collapse
Affiliation(s)
- Jean-Simon Brouard
- Département de biochimie, de microbiologie et de bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| | - Monique Turmel
- Département de biochimie, de microbiologie et de bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| | - Christian Otis
- Département de biochimie, de microbiologie et de bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| | - Claude Lemieux
- Département de biochimie, de microbiologie et de bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| |
Collapse
|
38
|
Chloroplast DNA Structural Variation, Phylogeny, and Age of Divergence among Diploid Cotton Species. PLoS One 2016; 11:e0157183. [PMID: 27309527 PMCID: PMC4911064 DOI: 10.1371/journal.pone.0157183] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/25/2016] [Indexed: 12/20/2022] Open
Abstract
The cotton genus (Gossypium spp.) contains 8 monophyletic diploid genome groups (A, B, C, D, E, F, G, K) and a single allotetraploid clade (AD). To gain insight into the phylogeny of Gossypium and molecular evolution of the chloroplast genome in this group, we performed a comparative analysis of 19 Gossypium chloroplast genomes, six reported here for the first time. Nucleotide distance in non-coding regions was about three times that of coding regions. As expected, distances were smaller within than among genome groups. Phylogenetic topologies based on nucleotide and indel data support for the resolution of the 8 genome groups into 6 clades. Phylogenetic analysis of indel distribution among the 19 genomes demonstrates contrasting evolutionary dynamics in different clades, with a parallel genome downsizing in two genome groups and a biased accumulation of insertions in the clade containing the cultivated cottons leading to large (for Gossypium) chloroplast genomes. Divergence time estimates derived from the cpDNA sequence suggest that the major diploid clades had diverged approximately 10 to 11 million years ago. The complete nucleotide sequences of 6 cpDNA genomes are provided, offering a resource for cytonuclear studies in Gossypium.
Collapse
|
39
|
Shapiro JA. Nothing in Evolution Makes Sense Except in the Light of Genomics: Read-Write Genome Evolution as an Active Biological Process. BIOLOGY 2016; 5:E27. [PMID: 27338490 PMCID: PMC4929541 DOI: 10.3390/biology5020027] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/20/2016] [Accepted: 06/02/2016] [Indexed: 01/15/2023]
Abstract
The 21st century genomics-based analysis of evolutionary variation reveals a number of novel features impossible to predict when Dobzhansky and other evolutionary biologists formulated the neo-Darwinian Modern Synthesis in the middle of the last century. These include three distinct realms of cell evolution; symbiogenetic fusions forming eukaryotic cells with multiple genome compartments; horizontal organelle, virus and DNA transfers; functional organization of proteins as systems of interacting domains subject to rapid evolution by exon shuffling and exonization; distributed genome networks integrated by mobile repetitive regulatory signals; and regulation of multicellular development by non-coding lncRNAs containing repetitive sequence components. Rather than single gene traits, all phenotypes involve coordinated activity by multiple interacting cell molecules. Genomes contain abundant and functional repetitive components in addition to the unique coding sequences envisaged in the early days of molecular biology. Combinatorial coding, plus the biochemical abilities cells possess to rearrange DNA molecules, constitute a powerful toolbox for adaptive genome rewriting. That is, cells possess "Read-Write Genomes" they alter by numerous biochemical processes capable of rapidly restructuring cellular DNA molecules. Rather than viewing genome evolution as a series of accidental modifications, we can now study it as a complex biological process of active self-modification.
Collapse
Affiliation(s)
- James A Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago, GCIS W123B, 979 E. 57th Street, Chicago, IL 60637, USA.
| |
Collapse
|
40
|
Lemieux C, Otis C, Turmel M. Comparative Chloroplast Genome Analyses of Streptophyte Green Algae Uncover Major Structural Alterations in the Klebsormidiophyceae, Coleochaetophyceae and Zygnematophyceae. FRONTIERS IN PLANT SCIENCE 2016; 7:697. [PMID: 27252715 PMCID: PMC4877394 DOI: 10.3389/fpls.2016.00697] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/06/2016] [Indexed: 05/18/2023]
Abstract
The Streptophyta comprises all land plants and six main lineages of freshwater green algae: Mesostigmatophyceae, Chlorokybophyceae, Klebsormidiophyceae, Charophyceae, Coleochaetophyceae and Zygnematophyceae. Previous comparisons of the chloroplast genome from nine streptophyte algae (including four zygnematophyceans) revealed that, although land plant chloroplast DNAs (cpDNAs) inherited most of their highly conserved structural features from green algal ancestors, considerable cpDNA changes took place during the evolution of the Zygnematophyceae, the sister group of land plants. To gain deeper insights into the evolutionary dynamics of the chloroplast genome in streptophyte algae, we sequenced the cpDNAs of nine additional taxa: two klebsormidiophyceans (Entransia fimbriata and Klebsormidium sp. SAG 51.86), one coleocheatophycean (Coleochaete scutata) and six zygnematophyceans (Cylindrocystis brebissonii, Netrium digitus, Roya obtusa, Spirogyra maxima, Cosmarium botrytis and Closterium baillyanum). Our comparative analyses of these genomes with their streptophyte algal counterparts indicate that the large inverted repeat (IR) encoding the rDNA operon experienced loss or expansion/contraction in all three sampled classes and that genes were extensively shuffled in both the Klebsormidiophyceae and Zygnematophyceae. The klebsormidiophycean genomes boast greatly expanded IRs, with the Entransia 60,590-bp IR being the largest known among green algae. The 206,025-bp Entransia cpDNA, which is one of the largest genome among streptophytes, encodes 118 standard genes, i.e., four additional genes compared to its Klebsormidium flaccidum homolog. We inferred that seven of the 21 group II introns usually found in land plants were already present in the common ancestor of the Klebsormidiophyceae and its sister lineages. At 107,236 bp and with 117 standard genes, the Coleochaete IR-less genome is both the smallest and most compact among the streptophyte algal cpDNAs analyzed thus far; it lacks eight genes relative to its Chaetosphaeridium globosum homolog, four of which represent unique events in the evolutionary scenario of gene losses we reconstructed for streptophyte algae. The 10 compared zygnematophycean cpDNAs display tremendous variations at all levels, except gene content. During zygnematophycean evolution, the IR disappeared a minimum of five times, the rDNA operon was broken at four distinct sites, group II introns were lost on at least 43 occasions, and putative foreign genes, mainly of phage/viral origin, were gained.
Collapse
Affiliation(s)
- Claude Lemieux
- Institut de Biologie Intégrative et des Systèmes, Département de Biochimie, de Microbiologie et de Bio-informatique, Université Laval, QuébecQC, Canada
| | | | | |
Collapse
|
41
|
Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta) reveal complex patterns of sequence evolution. Mol Phylogenet Evol 2016; 98:176-83. [DOI: 10.1016/j.ympev.2016.01.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/08/2015] [Accepted: 01/19/2016] [Indexed: 01/16/2023]
|
42
|
Watanabe S, Fučíková K, Lewis LA, Lewis PO. Hiding in plain sight: Koshicola spirodelophila gen. et sp. nov. (Chaetopeltidales, Chlorophyceae), a novel green alga associated with the aquatic angiosperm Spirodela polyrhiza. AMERICAN JOURNAL OF BOTANY 2016; 103:865-75. [PMID: 27208355 DOI: 10.3732/ajb.1500481] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/04/2016] [Indexed: 05/25/2023]
Abstract
PREMISE OF THE STUDY Discovery and morphological characterization of a novel epiphytic aquatic green alga increases our understanding of Chaetopeltidales, a poorly known order in Chlorophyceae. Chloroplast genomic data from this taxon reveals an unusual architecture previously unknown in green algae. METHODS Using light and electron microscopy, we characterized the morphology and ultrastructure of a novel taxon of green algae. Bayesian phylogenetic analyses of nuclear and plastid genes were used to test the hypothesized membership of this taxon in order Chaetopeltidales. With next-generation sequence data, we assembled the plastid genome of this novel taxon and compared its gene content and architecture to that of related species to further investigate plastid genome traits. KEY RESULTS The morphology and ultrastructure of this alga are consistent with placement in Chaetopeltidales (Chlorophyceae), but a distinct trait combination supports recognition of this alga as a new genus and species-Koshicola spirodelophila gen. et sp. nov. Its placement in the phylogeny as a descendant of a deep division in the Chaetopeltidales is supported by analysis of molecular data sets. The chloroplast genome is among the largest reported in green algae and the genes are distributed on three large (rather than a single) chromosome, in contrast to other studied green algae. CONCLUSIONS The discovery of Koshicola spirodelophila gen. et sp. nov. highlights the importance of investigating even commonplace habitats to explore new microalgal diversity. This work expands our understanding of the morphological and chloroplast genomic features of green algae, and in particular those of the poorly studied Chaetopeltidales.
Collapse
Affiliation(s)
- Shin Watanabe
- Department of Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
| | - Karolina Fučíková
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, Connecticut 06269 USA
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, Connecticut 06269 USA
| | - Paul O Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, Connecticut 06269 USA
| |
Collapse
|
43
|
Turmel M, de Cambiaire JC, Otis C, Lemieux C. Distinctive Architecture of the Chloroplast Genome in the Chlorodendrophycean Green Algae Scherffelia dubia and Tetraselmis sp. CCMP 881. PLoS One 2016; 11:e0148934. [PMID: 26849226 PMCID: PMC4743939 DOI: 10.1371/journal.pone.0148934] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/23/2016] [Indexed: 12/29/2022] Open
Abstract
The Chlorodendrophyceae is a small class of green algae belonging to the core Chlorophyta, an assemblage that also comprises the Pedinophyceae, Trebouxiophyceae, Ulvophyceae and Chlorophyceae. Here we describe for the first time the chloroplast genomes of chlorodendrophycean algae (Scherffelia dubia, 137,161 bp; Tetraselmis sp. CCMP 881, 100,264 bp). Characterized by a very small single-copy (SSC) region devoid of any gene and an unusually large inverted repeat (IR), the quadripartite structures of the Scherffelia and Tetraselmis genomes are unique among all core chlorophytes examined thus far. The lack of genes in the SSC region is offset by the rich and atypical gene complement of the IR, which includes genes from the SSC and large single-copy regions of prasinophyte and streptophyte chloroplast genomes having retained an ancestral quadripartite structure. Remarkably, seven of the atypical IR-encoded genes have also been observed in the IRs of pedinophycean and trebouxiophycean chloroplast genomes, suggesting that they were already present in the IR of the common ancestor of all core chlorophytes. Considering that the relationships among the main lineages of the core Chlorophyta are still unresolved, we evaluated the impact of including the Chlorodendrophyceae in chloroplast phylogenomic analyses. The trees we inferred using data sets of 79 and 108 genes from 71 chlorophytes indicate that the Chlorodendrophyceae is a deep-diverging lineage of the core Chlorophyta, although the placement of this class relative to the Pedinophyceae remains ambiguous. Interestingly, some of our phylogenomic trees together with our comparative analysis of gene order data support the monophyly of the Trebouxiophyceae, thus offering further evidence that the previously observed affiliation between the Chlorellales and Pedinophyceae is the result of systematic errors in phylogenetic reconstruction.
Collapse
Affiliation(s)
- Monique Turmel
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Québec, Canada
- * E-mail:
| | - Jean-Charles de Cambiaire
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Québec, Canada
| | - Christian Otis
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Québec, Canada
| | - Claude Lemieux
- Institut de Biologie Intégrative et des Systèmes, Département de biochimie, de microbiologie et de bio-informatique, Université Laval, Québec, Québec, Canada
| |
Collapse
|
44
|
Vincent AT, Trudel MV, Freschi L, Nagar V, Gagné-Thivierge C, Levesque RC, Charette SJ. Increasing genomic diversity and evidence of constrained lifestyle evolution due to insertion sequences in Aeromonas salmonicida. BMC Genomics 2016; 17:44. [PMID: 26753691 PMCID: PMC4709979 DOI: 10.1186/s12864-016-2381-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/06/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Aeromonads make up a group of Gram-negative bacteria that includes human and fish pathogens. The Aeromonas salmonicida species has the peculiarity of including five known subspecies. However, few studies of the genomes of A. salmonicida subspecies have been reported to date. RESULTS We sequenced the genomes of additional A. salmonicida isolates, including three from India, using next-generation sequencing in order to gain a better understanding of the genomic and phylogenetic links between A. salmonicida subspecies. Their relative phylogenetic positions were confirmed by a core genome phylogeny based on 1645 gene sequences. The Indian isolates, which formed a sub-group together with A. salmonicida subsp. pectinolytica, were able to grow at either at 18 °C and 37 °C, unlike the A. salmonicida psychrophilic isolates that did not grow at 37 °C. Amino acid frequencies, GC content, tRNA composition, loss and gain of genes during evolution, pseudogenes as well as genes under positive selection and the mobilome were studied to explain this intraspecies dichotomy. CONCLUSION Insertion sequences appeared to be an important driving force that locked the psychrophilic strains into their particular lifestyle in order to conserve their genomic integrity. This observation, based on comparative genomics, is in agreement with previous results showing that insertion sequence mobility induced by heat in A. salmonicida subspecies causes genomic plasticity, resulting in a deleterious effect on the virulence of the bacterium. We provide a proof-of-concept that selfish DNAs play a major role in the evolution of bacterial species by modeling genomes.
Collapse
Affiliation(s)
- Antony T Vincent
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Mélanie V Trudel
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Luca Freschi
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Département de microbiologie-infectiologie et immunologie, Faculté de médecine, Université Laval, Quebec City, QC, Canada.
| | - Vandan Nagar
- Food Technology Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - Cynthia Gagné-Thivierge
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| | - Roger C Levesque
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Département de microbiologie-infectiologie et immunologie, Faculté de médecine, Université Laval, Quebec City, QC, Canada.
| | - Steve J Charette
- Institut de biologie intégrative et des systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, 1030 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (Hôpital Laval), 2725 Chemin Sainte-Foy, Quebec City, G1V 4G5, QC, Canada.
- Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, 1045 avenue de la Médecine, Quebec City, G1V 0A6, QC, Canada.
| |
Collapse
|
45
|
Chloroplast phylogenomic analysis of chlorophyte green algae identifies a novel lineage sister to the Sphaeropleales (Chlorophyceae). BMC Evol Biol 2015; 15:264. [PMID: 26620802 PMCID: PMC4665822 DOI: 10.1186/s12862-015-0544-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/17/2015] [Indexed: 01/29/2023] Open
Abstract
Background The class Chlorophyceae (Chlorophyta) includes morphologically and ecologically diverse green algae. Most of the documented species belong to the clade formed by the Chlamydomonadales (also called Volvocales) and Sphaeropleales. Although studies based on the nuclear 18S rRNA gene or a few combined genes have shed light on the diversity and phylogenetic structure of the Chlamydomonadales, the positions of many of the monophyletic groups identified remain uncertain. Here, we used a chloroplast phylogenomic approach to delineate the relationships among these lineages. Results To generate the analyzed amino acid and nucleotide data sets, we sequenced the chloroplast DNAs (cpDNAs) of 24 chlorophycean taxa; these included representatives from 16 of the 21 primary clades previously recognized in the Chlamydomonadales, two taxa from a coccoid lineage (Jenufa) that was suspected to be sister to the Golenkiniaceae, and two sphaeroplealeans. Using Bayesian and/or maximum likelihood inference methods, we analyzed an amino acid data set that was assembled from 69 cpDNA-encoded proteins of 73 core chlorophyte (including 33 chlorophyceans), as well as two nucleotide data sets that were generated from the 69 genes coding for these proteins and 29 RNA-coding genes. The protein and gene phylogenies were congruent and robustly resolved the branching order of most of the investigated lineages. Within the Chlamydomonadales, 22 taxa formed an assemblage of five major clades/lineages. The earliest-diverging clade displayed Hafniomonas laevis and the Crucicarteria, and was followed by the Radicarteria and then by the Chloromonadinia. The latter lineage was sister to two superclades, one consisting of the Oogamochlamydinia and Reinhardtinia and the other of the Caudivolvoxa and Xenovolvoxa. To our surprise, the Jenufa species and the two spine-bearing green algae belonging to the Golenkinia and Treubaria genera were recovered in a highly supported monophyletic group that also included three taxa representing distinct families of the Sphaeropleales (Bracteacoccaceae, Mychonastaceae, and Scenedesmaceae). Conclusions Our phylogenomic study advances our knowledge regarding the circumscription and internal structure of the Chlamydomonadales, suggesting that a previously unrecognized lineage is sister to the Sphaeropleales. In addition, it offers new insights into the flagellar structures of the founding members of both the Chlamydomonadales and Sphaeropleales. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0544-5) contains supplementary material, which is available to authorized users.
Collapse
|
46
|
Turmel M, Otis C, Lemieux C. Dynamic Evolution of the Chloroplast Genome in the Green Algal Classes Pedinophyceae and Trebouxiophyceae. Genome Biol Evol 2015; 7:2062-82. [PMID: 26139832 PMCID: PMC4524492 DOI: 10.1093/gbe/evv130] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2015] [Indexed: 01/21/2023] Open
Abstract
Previous studies of trebouxiophycean chloroplast genomes revealed little information regarding the evolutionary dynamics of this genome because taxon sampling was too sparse and the relationships between the sampled taxa were unknown. We recently sequenced the chloroplast genomes of 27 trebouxiophycean and 2 pedinophycean green algae to resolve the relationships among the main lineages recognized for the Trebouxiophyceae. These taxa and the previously sampled members of the Pedinophyceae and Trebouxiophyceae are included in the comparative chloroplast genome analysis we report here. The 38 genomes examined display considerable variability at all levels, except gene content. Our results highlight the high propensity of the rDNA-containing large inverted repeat (IR) to vary in size, gene content and gene order as well as the repeated losses it experienced during trebouxiophycean evolution. Of the seven predicted IR losses, one event demarcates a superclade of 11 taxa representing 5 late-diverging lineages. IR expansions/contractions account not only for changes in gene content in this region but also for changes in gene order and gene duplications. Inversions also led to gene rearrangements within the IR, including the reversal or disruption of the rDNA operon in some lineages. Most of the 20 IR-less genomes are more rearranged compared with their IR-containing homologs and tend to show an accelerated rate of sequence evolution. In the IR-less superclade, several ancestral operons were disrupted, a few genes were fragmented, and a subgroup of taxa features a G+C-biased nucleotide composition. Our analyses also unveiled putative cases of gene acquisitions through horizontal transfer.
Collapse
Affiliation(s)
- Monique Turmel
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| | - Christian Otis
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| | - Claude Lemieux
- Département de Biochimie, de Microbiologie et de Bio-Informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada
| |
Collapse
|
47
|
Oborník M, Lukeš J. The Organellar Genomes of Chromera and Vitrella, the Phototrophic Relatives of Apicomplexan Parasites. Annu Rev Microbiol 2015; 69:129-44. [PMID: 26092225 DOI: 10.1146/annurev-micro-091014-104449] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Apicomplexa are known to contain greatly reduced organellar genomes. Their mitochondrial genome carries only three protein-coding genes, and their plastid genome is reduced to a 35-kb-long circle. The discovery of coral-endosymbiotic algae Chromera velia and Vitrella brassicaformis, which share a common ancestry with Apicomplexa, provided an opportunity to study possibly ancestral forms of organellar genomes, a unique glimpse into the evolutionary history of apicomplexan parasites. The structurally similar mitochondrial genomes of Chromera and Vitrella differ in gene content, which is reflected in the composition of their respiratory chains. Thus, Chromera lacks respiratory complexes I and III, whereas Vitrella and apicomplexan parasites are missing only complex I. Plastid genomes differ substantially between these algae, particularly in structure: The Chromera plastid genome is a linear, 120-kb molecule with large and divergent genes, whereas the plastid genome of Vitrella is a highly compact circle that is only 85 kb long but nonetheless contains more genes than that of Chromera. It appears that organellar genomes have already been reduced in free-living phototrophic ancestors of apicomplexan parasites, and such reduction is not associated with parasitism.
Collapse
|
48
|
Melton JT, Leliaert F, Tronholm A, Lopez-Bautista JM. The complete chloroplast and mitochondrial genomes of the green macroalga Ulva sp. UNA00071828 (Ulvophyceae, Chlorophyta). PLoS One 2015; 10:e0121020. [PMID: 25849557 PMCID: PMC4388391 DOI: 10.1371/journal.pone.0121020] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/09/2015] [Indexed: 11/18/2022] Open
Abstract
Sequencing mitochondrial and chloroplast genomes has become an integral part in understanding the genomic machinery and the phylogenetic histories of green algae. Previously, only three chloroplast genomes (Oltmannsiellopsis viridis, Pseudendoclonium akinetum, and Bryopsis hypnoides) and two mitochondrial genomes (O. viridis and P. akinetum) from the class Ulvophyceae have been published. Here, we present the first chloroplast and mitochondrial genomes from the ecologically and economically important marine, green algal genus Ulva. The chloroplast genome of Ulva sp. was 99,983 bp in a circular-mapping molecule that lacked inverted repeats, and thus far, was the smallest ulvophycean plastid genome. This cpDNA was a highly compact, AT-rich genome that contained a total of 102 identified genes (71 protein-coding genes, 28 tRNA genes, and three ribosomal RNA genes). Additionally, five introns were annotated in four genes: atpA (1), petB (1), psbB (2), and rrl (1). The circular-mapping mitochondrial genome of Ulva sp. was 73,493 bp and follows the expanded pattern also seen in other ulvophyceans and trebouxiophyceans. The Ulva sp. mtDNA contained 29 protein-coding genes, 25 tRNA genes, and two rRNA genes for a total of 56 identifiable genes. Ten introns were annotated in this mtDNA: cox1 (4), atp1 (1), nad3 (1), nad5 (1), and rrs (3). Double-cut-and-join (DCJ) values showed that organellar genomes across Chlorophyta are highly rearranged, in contrast to the highly conserved organellar genomes of the red algae (Rhodophyta). A phylogenomic investigation of 51 plastid protein-coding genes showed that Ulvophyceae is not monophyletic, and also placed Oltmannsiellopsis (Oltmannsiellopsidales) and Tetraselmis (Chlorodendrophyceae) closely to Ulva (Ulvales) and Pseudendoclonium (Ulothrichales).
Collapse
Affiliation(s)
- James T. Melton
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487-0345, United States of America
- * E-mail:
| | - Frederik Leliaert
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487-0345, United States of America
- Marine Biology Research Group, Department of Biology, Ghent University, Krijgslaan 281-S8, 9000 Ghent, Belgium
| | - Ana Tronholm
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487-0345, United States of America
- Smithsonian Marine Station at Fort Pierce, 701 Seaway Drive, Fort Pierce, Florida 34949, United States of America
| | - Juan M. Lopez-Bautista
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama 35487-0345, United States of America
| |
Collapse
|
49
|
Mitochondrial and plastid genome architecture: Reoccurring themes, but significant differences at the extremes. Proc Natl Acad Sci U S A 2015; 112:10177-84. [PMID: 25814499 DOI: 10.1073/pnas.1422049112] [Citation(s) in RCA: 243] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial and plastid genomes show a wide array of architectures, varying immensely in size, structure, and content. Some organelle DNAs have even developed elaborate eccentricities, such as scrambled coding regions, nonstandard genetic codes, and convoluted modes of posttranscriptional modification and editing. Here, we compare and contrast the breadth of genomic complexity between mitochondrial and plastid chromosomes. Both organelle genomes have independently evolved many of the same features and taken on similar genomic embellishments, often within the same species or lineage. This trend is most likely because the nuclear-encoded proteins mediating these processes eventually leak from one organelle into the other, leading to a high likelihood of processes appearing in both compartments in parallel. However, the complexity and intensity of genomic embellishments are consistently more pronounced for mitochondria than for plastids, even when they are found in both compartments. We explore the evolutionary forces responsible for these patterns and argue that organelle DNA repair processes, mutation rates, and population genetic landscapes are all important factors leading to the observed convergence and divergence in organelle genome architecture.
Collapse
|
50
|
Leliaert F, Lopez-Bautista JM. The chloroplast genomes of Bryopsis plumosa and Tydemania expeditiones (Bryopsidales, Chlorophyta): compact genomes and genes of bacterial origin. BMC Genomics 2015; 16:204. [PMID: 25879186 PMCID: PMC4487195 DOI: 10.1186/s12864-015-1418-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 02/28/2015] [Indexed: 12/31/2022] Open
Abstract
Background Species of Bryopsidales form ecologically important components of seaweed communities worldwide. These siphonous macroalgae are composed of a single giant tubular cell containing millions of nuclei and chloroplasts, and harbor diverse bacterial communities. Little is known about the diversity of chloroplast genomes (cpDNAs) in this group, and about the possible consequences of intracellular bacteria on genome composition of the host. We present the complete cpDNAs of Bryopsis plumosa and Tydemania expeditiones, as well as a re-annotated cpDNA of B. hypnoides, which was shown to contain a higher number of genes than originally published. Chloroplast genomic data were also used to evaluate phylogenetic hypotheses in the Chlorophyta, such as monophyly of the Ulvophyceae (the class in which the order Bryopsidales is currently classified). Results Both DNAs are circular and lack a large inverted repeat. The cpDNA of B. plumosa is 106,859 bp long and contains 115 unique genes. A 13 kb region was identified with several freestanding open reading frames (ORFs) of putative bacterial origin, including a large ORF (>8 kb) closely related to bacterial rhs-family genes. The cpDNA of T. expeditiones is 105,200 bp long and contains 125 unique genes. As in B. plumosa, several regions were identified with ORFs of possible bacterial origin, including genes involved in mobile functions (transposases, integrases, phage/plasmid DNA primases), and ORFs showing close similarity with bacterial DNA methyltransferases. The cpDNA of B. hypnoides differs from that of B. plumosa mainly in the presence of long intergenic spacers, and a large tRNA region. Chloroplast phylogenomic analyses were largely inconclusive with respect to monophyly of the Ulvophyceae, and the relationship of the Bryopsidales within the Chlorophyta. Conclusions The cpDNAs of B. plumosa and T. expeditiones are amongst the smallest and most gene dense chloroplast genomes in the core Chlorophyta. The presence of bacterial genes, including genes typically found in mobile elements, suggest that these have been acquired through horizontal gene transfer, which may have been facilitated by the occurrence of obligate intracellular bacteria in these siphonous algae. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1418-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Frederik Leliaert
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, USA. .,Department of Biology, Marine Biology Research Group, Ghent University, Krijgslaan 281-S8, Ghent, 9000, Belgium.
| | | |
Collapse
|