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Cho A, Lax G, Keeling PJ. Phylogenomic analyses of ochrophytes (stramenopiles) with an emphasis on neglected lineages. Mol Phylogenet Evol 2024; 198:108120. [PMID: 38852907 DOI: 10.1016/j.ympev.2024.108120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 05/13/2024] [Accepted: 06/04/2024] [Indexed: 06/11/2024]
Abstract
Ochrophyta is a photosynthetic lineage that crowns the phylogenetic tree of stramenopiles, one of the major eukaryotic supergroups. Due to their ecological impact as a major primary producer, ochrophytes are relatively well-studied compared to the rest of the stramenopiles, yet their evolutionary relationships remain poorly understood. This is in part due to a number of missing lineages in large-scale multigene analyses, and an apparently rapid radiation leading to many short internodes between ochrophyte subgroups in the tree. These short internodes are also found across deep-branching lineages of stramenopiles with limited phylogenetic signal, leaving many relationships controversial overall. We have addressed this issue with other deep-branching stramenopiles recently, and now examine whether contentious relationships within the ochrophytes may be resolved with the help of filling in missing lineages in an updated phylogenomic dataset of ochrophytes, along with exploring various gene filtering criteria to identify the most phylogenetically informative genes. We generated ten new transcriptomes from various culture collections and a single-cell isolation from an environmental sample, added these to an existing phylogenomic dataset, and examined the effects of selecting genes with high phylogenetic signal or low phylogenetic noise. For some previously contentious relationships, we find a variety of analyses and gene filtering criteria consistently unite previously unstable groupings with strong statistical support. For example, we recovered a robust grouping of Eustigmatophyceae with Raphidophyceae-Phaeophyceae-Xanthophyceae while Olisthodiscophyceae formed a sister-lineage to Pinguiophyceae. Selecting genes with high phylogenetic signal or data quality recovered more stable topologies. Overall, we find that adding under-represented groups across different lineages is still crucial in resolving phylogenetic relationships, and discrete gene properties affect lineages of stramenopiles differently. This is something which may be explored to further our understanding of the molecular evolution of stramenopiles.
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Affiliation(s)
- Anna Cho
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada.
| | - Gordon Lax
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
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2
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Safonov P, Berdieva M, Nassonova E, Skarlato S, Pozdnyakov I. The first arctic strain of Rhizochromulina: Morphology, ultrastructure, and position in the evolutionary tree of the order Rhizochromulinales (Heterokontophyta, Dictyochophyceae). Eur J Protistol 2024; 92:126050. [PMID: 38150922 DOI: 10.1016/j.ejop.2023.126050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 12/29/2023]
Abstract
Rhizochromulina marina is a unicellular amoeboid alga capable of forming flagellate cells; it is a single validly named species in the genus. Besides, there are numerous environmental sequences and undescribed strains designated as Rhizochromulina sp. or R. marina. The biogeography of the genus is understudied: rhizochromulines from the Indian, Southern, and Arctic Oceans are unknown. Here, we present the description of Rhizochromulina sp. B44, which was for the first time isolated from an arctic habitat. Biofilms of this microalga grow at the bottom of a culture vessel, where neighbouring amoeboid cells form associations through a common network of pseudopodia, i.e. meroplasmodia. Pseudopodia branch, anastomose mainly during meroplasmodia formation, and are supported by microtubules that arise from the perinuclear zone. Actin filaments are localized in the cytoplasm and can be revealed only near the bases of pseudopodia. We succeeded in inducing the transformation of amoeboid cells into flagellates using a prolonged agitation of cultures. Morphological and molecular analyses revealed that the studied strain is most closely related to the type strain of R. marina. At the same time, 18S rDNA sequences of early branching-off rhizochromulinids differ significantly from Rhizochromulina sp. B44, suggesting a high divergence at the genus level.
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Affiliation(s)
- Pavel Safonov
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg 194064, Russia.
| | - Mariia Berdieva
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg 194064, Russia
| | - Elena Nassonova
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg 194064, Russia; Saint Petersburg State University, Saint Petersburg 199034, Russia
| | - Sergei Skarlato
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg 194064, Russia
| | - Ilya Pozdnyakov
- Institute of Cytology, Russian Academy of Sciences, Saint Petersburg 194064, Russia
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3
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Barbaglia GS, Paight C, Honig M, Johnson MD, Marczak R, Lepori-Bui M, Moeller HV. Environment-dependent metabolic investments in the mixotrophic chrysophyte Ochromonas. JOURNAL OF PHYCOLOGY 2024; 60:170-184. [PMID: 38141034 DOI: 10.1111/jpy.13418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/06/2023] [Accepted: 11/15/2023] [Indexed: 12/24/2023]
Abstract
Mixotrophic protists combine photosynthesis and phagotrophy to obtain energy and nutrients. Because mixotrophs can act as either primary producers or consumers, they have a complex role in marine food webs and biogeochemical cycles. Many mixotrophs are also phenotypically plastic and can adjust their metabolic investments in response to resource availability. Thus, a single species's ecological role may vary with environmental conditions. Here, we quantified how light and food availability impacted the growth rates, energy acquisition rates, and metabolic investment strategies of eight strains of the mixotrophic chrysophyte, Ochromonas. All eight Ochromonas strains photoacclimated by decreasing chlorophyll content as light intensity increased. Some strains were obligate phototrophs that required light for growth, while other strains showed stronger metabolic responses to prey availability. When prey availability was high, all eight strains exhibited accelerated growth rates and decreased their investments in both photosynthesis and phagotrophy. Photosynthesis and phagotrophy generally produced additive benefits: In low-prey environments, Ochromonas growth rates increased to maximum, light-saturated rates with increasing light but increased further with the addition of abundant bacterial prey. The additive benefits observed between photosynthesis and phagotrophy in Ochromonas suggest that the two metabolic modes provide nonsubstitutable resources, which may explain why a tradeoff between phagotrophic and phototrophic investments emerged in some but not all strains.
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Affiliation(s)
- Gina S Barbaglia
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Christopher Paight
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Meredith Honig
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Matthew D Johnson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Ryan Marczak
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
| | - Michelle Lepori-Bui
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
- Washington Sea Grant, University of Washington, Seattle, Washington, USA
| | - Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California-Santa Barbara, Santa Barbara, California, USA
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4
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Wetherbee R, Bringloe TT, van de Meene A, Andersen RA, Verbruggen H. Structure and formation of the perforated theca defining the Pelagophyceae (Heterokonta), and three new genera that substantiate the diverse nature of the class. JOURNAL OF PHYCOLOGY 2023; 59:126-151. [PMID: 36326615 DOI: 10.1111/jpy.13294] [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: 07/18/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
The pelagophytes, a morphologically diverse class of marine heterokont algae, have been historically united only by DNA sequences. Recently we described a novel perforated theca (PT) encasing cells from the Pelagophyceae and hypothesized it may be the first morphological feature to define the class. Here we consolidate that observation, describing a PT for the first time in an additional seven pelagophyte genera, including three genera new to science. We established clonal cultures of pelagophytes collected from intertidal pools located around Australia, and established phylogenetic trees based on nuclear 18S rDNA and plastid rbcL, psaA, psaB, psbA and psbC gene sequences that led to the discovery of three new species: Wyeophycus julieharrissiae and Chromopallida australis form a distinct lineage along with Ankylochrysis lutea within the Pelagomonadales, while Pituiglomerulus capricornicus is sister genus to Chrysocystis fragilis in the Chrysocystaceae (Sarcinochrysidales). Using fixation by high-pressure freezing for electron microscope observations, a distinctive PT was observed in the three new genera described in this paper, as well as four genera not previously investigated: Chrysoreinhardia, Sargassococcus, Sungminbooa and Andersenia. The mechanism of PT formation is novel, being fabricated from rafts in Golgi-derived vesicles before being inserted into an established PT. Extracellular wall and/or mucilage layers assemble exterior to the PT in most pelagophytes, the materials likewise secreted by Golgi-derived vesicles, though the mechanism of secretion is novel. Secretory vesicles never fuse with the plasma membrane as in classic secretion and deposition, but rather relocate extracellularly beneath the PT and disintegrate, the contents having to pass through the PT prior to wall and/or mucilage synthesis. This study substantiates the diverse nature of pelagophytes, and provides further evidence that the PT is a sound morphological feature to define the Pelagophyceae, with all 14 of the 20 known genera studied to date by TEM possessing a PT.
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Affiliation(s)
- Richard Wetherbee
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Trevor T Bringloe
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Allison van de Meene
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Seattle, Washington, USA
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
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Graf L, Shin Y, Yang JH, Hwang IK, Yoon HS. Transcriptome analysis reveals the spatial and temporal differentiation of gene expression in the sporophyte of Undaria pinnatifida. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bai Y, Cao T, Dautermann O, Buschbeck P, Cantrell MB, Chen Y, Lein CD, Shi X, Ware MA, Yang F, Zhang H, Zhang L, Peers G, Li X, Lohr M. Green diatom mutants reveal an intricate biosynthetic pathway of fucoxanthin. Proc Natl Acad Sci U S A 2022; 119:e2203708119. [PMID: 36095219 PMCID: PMC9499517 DOI: 10.1073/pnas.2203708119] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 08/08/2022] [Indexed: 01/17/2023] Open
Abstract
Fucoxanthin is a major light-harvesting pigment in ecologically important algae such as diatoms, haptophytes, and brown algae (Phaeophyceae). Therefore, it is a major driver of global primary productivity. Species of these algal groups are brown colored because the high amounts of fucoxanthin bound to the proteins of their photosynthetic machineries enable efficient absorption of green light. While the structure of these fucoxanthin-chlorophyll proteins has recently been resolved, the biosynthetic pathway of fucoxanthin is still unknown. Here, we identified two enzymes central to this pathway by generating corresponding knockout mutants of the diatom Phaeodactylum tricornutum that are green due to the lack of fucoxanthin. Complementation of the mutants with the native genes or orthologs from haptophytes restored fucoxanthin biosynthesis. We propose a complete biosynthetic path to fucoxanthin in diatoms and haptophytes based on the carotenoid intermediates identified in the mutants and in vitro biochemical assays. It is substantially more complex than anticipated and reveals diadinoxanthin metabolism as the central regulatory hub connecting the photoprotective xanthophyll cycle and the formation of fucoxanthin. Moreover, our data show that the pathway evolved by repeated duplication and neofunctionalization of genes for the xanthophyll cycle enzymes violaxanthin de-epoxidase and zeaxanthin epoxidase. Brown algae lack diadinoxanthin and the genes described here and instead use an alternative pathway predicted to involve fewer enzymes. Our work represents a major step forward in elucidating the biosynthesis of fucoxanthin and understanding the evolution, biogenesis, and regulation of the photosynthetic machinery in algae.
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Affiliation(s)
- Yu Bai
- Department of Biology, Colorado State University, Fort Collins, CO 80523-1878
| | - Tianjun Cao
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Oliver Dautermann
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, 55099 Mainz, Germany
| | - Paul Buschbeck
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, 55099 Mainz, Germany
| | - Michael B. Cantrell
- Department of Biology, Colorado State University, Fort Collins, CO 80523-1878
| | - Yinjuan Chen
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Christopher D. Lein
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, 55099 Mainz, Germany
| | - Xiaohuo Shi
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou 310024, China
| | - Maxwell A. Ware
- Department of Biology, Colorado State University, Fort Collins, CO 80523-1878
| | - Fenghua Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
| | - Huan Zhang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Lihan Zhang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Westlake University, Hangzhou 310024, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Graham Peers
- Department of Biology, Colorado State University, Fort Collins, CO 80523-1878
| | - Xiaobo Li
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Martin Lohr
- Institut für Molekulare Physiologie, Johannes Gutenberg-Universität, 55099 Mainz, Germany
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7
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Barcytė D, Zátopková M, Němcová Y, Richtář M, Yurchenko T, Jaške K, Fawley KP, Škaloud P, Ševčíková T, Fawley MW, Eliáš M. Redefining Chlorobotryaceae as one of the principal and most diverse lineages of eustigmatophyte algae. Mol Phylogenet Evol 2022; 177:107607. [PMID: 35963589 DOI: 10.1016/j.ympev.2022.107607] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/11/2022] [Accepted: 08/05/2022] [Indexed: 10/15/2022]
Abstract
Eustigmatophyceae is one of the ∼17 classes of the vast algal phylum Ochrophyta. Over the last decade, the eustigmatophytes emerged as an expansive group that has grown from the initially recognized handful of species to well over 200 genetically distinct entities (potential species). Yet the majority of eustigs, remain represented by unidentified strains, or even only metabarcode sequences obtained from environmental samples. Moreover, the formal classification of the group has not yet been harmonized with the recently uncovered diversity and phylogenetic relationships within the class. Here we make a major step towards resolving this issue by addressing the diversity, phylogeny and classification of one of the most prominent eustigmatophyte clades previously informally called the "Eustigmataceae group". We obtained 18S rDNA and rbcL gene sequences from four new strains from the "Eustigmataceae group", and from several additional eustig strains, and performed the most comprehensive phylogenetic analyses of Eustigmatophyceae to date. Our results of these analyses confirm the monophyly of the "Eustigmataceae group" and define its major subclades. We also sequenced plastid genomes of five "Eustigmataceae group" strains to not only improve our understanding of the plastid gene content evolution in eustigs, but also to obtain a robustly resolved eustigmatophyte phylogeny. With this new genomic data, we have solidified the view of the "Eustigmataceae group" as a well-defined family level clade. Crucially, we also have firmly established the genus Chlorobotrys as a member of the "Eustigmataceae group". This new molecular evidence, together with a critical analysis of the literature going back to the 19th century, provided the basis to radically redefine the historical concept of the family Chlorobotryaceae as the formal taxonomic rubric corresponding to the "Eustigmataceae group". With this change, the family names Eustigmataceae and Characiopsidaceae are reduced to synonymy with the Chlorobotryaceae, with the latter having taxonomic priority. We additionally studied in detail the morphology and ultrastructure of two Chlorobotryaceae members, which we describe as Neustupella aerophytica gen. et sp. nov. and Lietzensia polymorpha gen. et sp. nov. Finally, our analyses of partial genomic data from several Chlorobotryaceae representatives identified genes for hallmark flagellar proteins in all of these strains. The presence of the flagellar proteins strongly suggests that zoosporogenesis is a common trait of the family and also occurs in the members never observed to produce flagellated stages. Altogether, our work paints a rich picture of one of the most diverse principal lineages of eustigmatophyte algae.
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Affiliation(s)
- Dovilė Barcytė
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
| | - Martina Zátopková
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Yvonne Němcová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 00 Prague, Czech Republic
| | - Michal Richtář
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Tatiana Yurchenko
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Karin Jaške
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Karen P Fawley
- Division of Science and Mathematics, University of the Ozarks, Clarksville, AR 72830, USA
| | - Pavel Škaloud
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 00 Prague, Czech Republic
| | - Tereza Ševčíková
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Marvin W Fawley
- Division of Science and Mathematics, University of the Ozarks, Clarksville, AR 72830, USA
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
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8
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Di Franco A, Baurain D, Glöckner G, Melkonian M, Philippe H. Lower statistical support with larger datasets: insights from the Ochrophyta radiation. Mol Biol Evol 2021; 39:6409865. [PMID: 34694402 PMCID: PMC8763130 DOI: 10.1093/molbev/msab300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
It is commonly assumed that increasing the number of characters has the potential to resolve evolutionary radiations. Here, we studied photosynthetic stramenopiles (Ochrophyta) using alignments of heterogeneous origin mitochondrion, plastid, and nucleus. Surprisingly while statistical support for the relationships between the six major Ochrophyta lineages increases when comparing the mitochondrion (6,762 sites) and plastid (21,692 sites) trees, it decreases in the nuclear (209,105 sites) tree. Statistical support is not simply related to the data set size but also to the quantity of phylogenetic signal available at each position and our ability to extract it. Here, we show that this ability for current phylogenetic methods is limited, because conflicting results were obtained when varying taxon sampling. Even though the use of a better fitting model improved signal extraction and reduced the observed conflicts, the plastid data set provided higher statistical support for the ochrophyte radiation than the larger nucleus data set. We propose that the higher support observed in the plastid tree is due to an acceleration of the evolutionary rate in one short deep internal branch, implying that more phylogenetic signal per position is available to resolve the Ochrophyta radiation in the plastid than in the nuclear data set. Our work therefore suggests that, in order to resolve radiations, beyond the obvious use of data sets with more positions, we need to continue developing models of sequence evolution that better extract the phylogenetic signal and design methods to search for genes/characters that contain more signal specifically for short internal branches.
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Affiliation(s)
- Arnaud Di Franco
- Station d'Ecologie Théorique et Expérimentale de Moulis, UMR CNRS 5321, Moulis, France
| | - Denis Baurain
- InBioS-PhytoSYSTEMS, Unité de Phylogénomique des Eucaryotes, Université de Liège, Liège, Belgium
| | - Gernot Glöckner
- Institut für Biochemie I, Medizinische Fakultät, Universität zu Köln, Köln, Germany
| | - Michael Melkonian
- Max Planck Institute for Plant Breeding Research, Integrative Bioinformatics, Cologne, Germany
| | - Hervé Philippe
- Station d'Ecologie Théorique et Expérimentale de Moulis, UMR CNRS 5321, Moulis, France.,Département de Biochimie, Centre Robert-Cedergren, Université de Montréal, Montréal, Québec, Canada
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9
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Graf L, Yoon HS. Olisthodiscophyceae, the 17th heterokont algal class. JOURNAL OF PHYCOLOGY 2021; 57:1091-1093. [PMID: 34289104 DOI: 10.1111/jpy.13184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
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10
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Barcytė D, Eikrem W, Engesmo A, Seoane S, Wohlmann J, Horák A, Yurchenko T, Eliáš M. Olisthodiscus represents a new class of Ochrophyta. JOURNAL OF PHYCOLOGY 2021; 57:1094-1118. [PMID: 33655496 DOI: 10.1111/jpy.13155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 12/08/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
The phylogenetic diversity of Ochrophyta, a diverse and ecologically important radiation of algae, is still incompletely understood even at the level of the principal lineages. One taxon that has eluded simple classification is the marine flagellate genus Olisthodiscus. We investigated Olisthodiscus luteus K-0444 and documented its morphological and genetic differences from the NIES-15 strain, which we described as Olisthodiscus tomasii sp. nov. Phylogenetic analyses of combined 18S and 28S rRNA sequences confirmed that Olisthodiscus constitutes a separate, deep, ochrophyte lineage, but its position could not be resolved. To overcome this problem, we sequenced the plastid genome of O. luteus K-0444 and used the new data in multigene phylogenetic analyses, which suggested that Olisthodiscus is a sister lineage of the class Pinguiophyceae within a broader clade additionally including Chrysophyceae, Synchromophyceae, and Eustigmatophyceae. Surprisingly, the Olisthodiscus plastid genome contained three genes, ycf80, cysT, and cysW, inherited from the rhodophyte ancestor of the ochrophyte plastid yet lost from all other ochrophyte groups studied so far. Combined with nuclear genes for CysA and Sbp proteins, Olisthodiscus is the only known ochrophyte possessing a plastidial sulfate transporter SulT. In addition, the finding of a cemA gene in the Olisthodiscus plastid genome and an updated phylogenetic analysis ruled out the previously proposed hypothesis invoking horizontal cemA transfer from a green algal plastid into Synurales. Altogether, Olisthodiscus clearly represents a novel phylogenetically distinct ochrophyte lineage, which we have proposed as a new class, Olisthodiscophyceae.
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Affiliation(s)
- Dovilė Barcytė
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Wenche Eikrem
- Norwegian Institute for Water Research, Gaustadallèen 21, 0349, Oslo, Norway
- Natural history Museum, University of Oslo, P.O. Box 1172 Blindern, 0318, Oslo, Norway
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Anette Engesmo
- Norwegian Institute for Water Research, Gaustadallèen 21, 0349, Oslo, Norway
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Sergio Seoane
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48940, Leioa, Spain
| | - Jens Wohlmann
- Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0316, Oslo, Norway
| | - Aleš Horák
- Biology Centre, Czech Academy of Sciences, Institute of Parasitology, Branišovská 31, 37005, České Budějovice, Czech Republic
- Department of Molecular Biology, Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Tatiana Yurchenko
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, 710 00, Ostrava, Czech Republic
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11
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Phylogenomic fingerprinting of tempo and functions of horizontal gene transfer within ochrophytes. Proc Natl Acad Sci U S A 2021; 118:2009974118. [PMID: 33419955 DOI: 10.1073/pnas.2009974118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Horizontal gene transfer (HGT) is an important source of novelty in eukaryotic genomes. This is particularly true for the ochrophytes, a diverse and important group of algae. Previous studies have shown that ochrophytes possess a mosaic of genes derived from bacteria and eukaryotic algae, acquired through chloroplast endosymbiosis and from HGTs, although understanding of the time points and mechanisms underpinning these transfers has been restricted by the depth of taxonomic sampling possible. We harness an expanded set of ochrophyte sequence libraries, alongside automated and manual phylogenetic annotation, in silico modeling, and experimental techniques, to assess the frequency and functions of HGT across this lineage. Through manual annotation of thousands of single-gene trees, we identify continuous bacterial HGT as the predominant source of recently arrived genes in the model diatom Phaeodactylum tricornutum Using a large-scale automated dataset, a multigene ochrophyte reference tree, and mathematical reconciliation of gene trees, we note a probable elevation of bacterial HGTs at foundational points in diatom evolution, following their divergence from other ochrophytes. Finally, we demonstrate that throughout ochrophyte evolutionary history, bacterial HGTs have been enriched in genes encoding secreted proteins. Our study provides insights into the sources and frequency of HGTs, and functional contributions that HGT has made to algal evolution.
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12
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Solon AJ, Mastrangelo C, Vimercati L, Sommers P, Darcy JL, Gendron EMS, Porazinska DL, Schmidt SK. Gullies and Moraines Are Islands of Biodiversity in an Arid, Mountain Landscape, Asgard Range, Antarctica. Front Microbiol 2021; 12:654135. [PMID: 34177836 PMCID: PMC8222675 DOI: 10.3389/fmicb.2021.654135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/04/2021] [Indexed: 12/30/2022] Open
Abstract
Cold, dry, and nutrient-poor, the McMurdo Dry Valleys of Antarctica are among the most extreme terrestrial environments on Earth. Numerous studies have described microbial communities of low elevation soils and streams below glaciers, while less is known about microbial communities in higher elevation soils above glaciers. We characterized microbial life in four landscape features (habitats) of a mountain in Taylor Valley. These habitats varied significantly in soil moisture and include moist soils of a (1) lateral glacial moraine, (2) gully that terminates at the moraine, and very dry soils on (3) a southeastern slope and (4) dry sites near the gully. Using rRNA gene PCR amplicon sequencing of Bacteria and Archaea (16S SSU) and eukaryotes (18S SSU), we found that all habitat types harbored significantly different bacterial and eukaryotic communities and that these differences were most apparent when comparing habitats that had macroscopically visible soil crusts (gully and moraine) to habitats with no visible crusts (near gully and slope). These differences were driven by a relative predominance of Actinobacteria and a Colpodella sp. in non-crust habitats, and by phototrophic bacteria and eukaryotes (e.g., a moss) and predators (e.g., tardigrades) in habitats with biological soil crusts (gully and moraine). The gully and moraine also had significantly higher 16S and 18S ESV richness than the other two habitat types. We further found that many of the phototrophic bacteria and eukaryotes of the gully and moraine share high sequence identity with phototrophs from moist and wet areas elsewhere in the Dry Valleys and other cold desert ecosystems. These include a Moss (Bryum sp.), several algae (e.g., a Chlorococcum sp.) and cyanobacteria (e.g., Nostoc and Phormidium spp.). Overall, the results reported here broaden the diversity of habitat types that have been studied in the Dry Valleys of Antarctica and suggest future avenues of research to more definitively understand the biogeography and factors controlling microbial diversity in this unique ecosystem.
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Affiliation(s)
- Adam J Solon
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, CO, United States
| | - Claire Mastrangelo
- School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Lara Vimercati
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, CO, United States
| | - Pacifica Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, CO, United States
| | - John L Darcy
- Division of Biomedical Informatics and Personalized Medicine, University of Colorado-Anschutz Medical Campus, Denver, CO, United States
| | - Eli M S Gendron
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, United States
| | - Dorota L Porazinska
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, United States
| | - S K Schmidt
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Boulder, CO, United States
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13
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Li R, Jia X, Zhang J, Jia S, Liu T, Qu J, Wang X. The Complete Plastid Genomes of Seven Sargassaceae Species and Their Phylogenetic Analysis. FRONTIERS IN PLANT SCIENCE 2021; 12:747036. [PMID: 34804089 PMCID: PMC8602799 DOI: 10.3389/fpls.2021.747036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 10/04/2021] [Indexed: 05/03/2023]
Abstract
Sargassum is one of the most important genera of the family Sargassaceae in brown algae and is used to produce carrageenan, mannitol, iodine, and other economic substances. Here, seven complete plastid genomes of Sargassum ilicifolium var. conduplicatum, S. graminifolium, S. phyllocystum, S. muticum, S. feldmannii, S. mcclurei, and S. henslowianum were assembled using next-generation sequencing. The sizes of the seven circular genomes ranged from 124,258 to 124,563 bp, with two inverted regions and the same set of plastid genes, including 139 protein-coding genes (PCGs), 28 transfer (t)RNAs, and 6 ribosomal (r)RNAs. Compared with the other five available plastid genomes of Fucales, 136 PCGs were conserved, with two common ones shared with Coccophora langsdorfii, and one with S. fusiforme and S. horneri. The co-linear analysis identified two inversions of trnC(gca) and trnN(gtt) in ten Sargassum species, against S. horneri and C. langsdorfii. The phylogenetic analysis based on the plastid genomes of 55 brown algae (Phaeophyceae) showed four clades, whose ancient ancestor lived around 201.42 million years ago (Mya), and the internal evolutionary branches in Fucales started to be formed 92.52 Mya, while Sargassum species were divided into two subclades 14.33 Mya. Our novel plastid genomes provided evidence for the speciation of brown algae and plastid genomic evolution events.
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Affiliation(s)
- Ruoran Li
- College of Life Sciences, Yantai University, Yantai, China
| | - Xuli Jia
- College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jing Zhang
- School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Shangang Jia
- College of Grassland Science and Technology, China Agricultural University, Beijing, China
- *Correspondence: Shangang Jia,
| | - Tao Liu
- College of Life Sciences, Yantai University, Yantai, China
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
- Tao Liu,
| | - Jiangyong Qu
- College of Life Sciences, Yantai University, Yantai, China
- Jiangyong Qu,
| | - Xumin Wang
- College of Life Sciences, Yantai University, Yantai, China
- Xumin Wang,
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14
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Graf L, Yang EC, Han KY, Küpper FC, Benes KM, Oyadomari JK, Herbert RJH, Verbruggen H, Wetherbee R, Andersen RA, Yoon HS. Multigene Phylogeny, Morphological Observation and Re-examination of the Literature Lead to the Description of the Phaeosacciophyceae Classis Nova and Four New Species of the Heterokontophyta SI Clade. Protist 2020; 171:125781. [PMID: 33278705 DOI: 10.1016/j.protis.2020.125781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 01/19/2023]
Abstract
The relationships among the Aurearenophyceae, Phaeothamniophyceae, Phaeophyceae and Xanthophyceae lineages of the Heterokontophyta SI clade are not well known. By adding previously unexamined taxa related to these classes in a five gene phylogeny (SSU rRNA, atpB, psaA, psaB, rbcL), we recovered an assemblage of taxa previously unrecognized. We propose the class Phaeosacciophyceae class. nov., that includes Phaeosaccion collinsii, Phaeosaccion multiseriatum sp. nov., Phaeosaccion okellyi sp. nov., Antarctosaccion applanatum, Tetrasporopsis fuscescens, Tetrasporopsis moei sp. nov., and Psammochrysis cassiotisii gen. & sp. nov. We re-examine the literature for Chrysomeris, Nematochrysis, Chrysowaernella and the invalid name "Giraudyopsis" and conclude some taxa in previous studies are misidentified or misnamed, i.e. Chrysomeris and Chrysowaernella, respectively. We also show that Nematochrysis sessilis var. vectensis and Nematochrysis hieroglyphica may belong in the recently described class Chrysoparadoxophyceae. The phylogenetic relationships of Phaeobotrys solitaria and Pleurochloridella botrydiopsis are not clearly resolved, but they branch near the Xanthophyceae. Here we describe a new class Phaeosacciophyceae, a new order Phaeosacciales, a new family Tetrasporopsidaceae, a new genus Psammochrysis and four new species.
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Affiliation(s)
- Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eun Chan Yang
- Marine Ecosystem Research Center, Korea Institute of Ocean Science and Technology, Busan 49111, Republic of Korea
| | - Kwi Young Han
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Frithjof C Küpper
- School of Biological Sciences, Cruickshank Bldg, University of Aberdeen, St. Machar Drive, Aberdeen AB24 3UU, Scotland, UK; Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK
| | - Kylla M Benes
- Davidson Honors College, University of Montana, Missoula, MT 59812, USA
| | - Jason K Oyadomari
- Suomi College of Arts and Sciences, Finlandia University, Hancock, MI 49930, USA
| | - Roger J H Herbert
- Department of Life and Environmental Sciences, Bournemouth University, Poole, Dorset BH12 5BB, UK
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Richard Wetherbee
- School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA.
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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15
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Molecular phylogeny and classification of the family Myxinidae (Cyclostomata: Myxiniformes) using the supermatrix method. JOURNAL OF ASIA-PACIFIC BIODIVERSITY 2020. [DOI: 10.1016/j.japb.2020.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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16
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Remias D, Nicoletti C, Krennhuber K, Möderndorfer B, Nedbalová L, Procházková L. Growth, fatty, and amino acid profiles of the soil alga Vischeria sp. E71.10 (Eustigmatophyceae) under different cultivation conditions. Folia Microbiol (Praha) 2020; 65:1017-1023. [PMID: 32696198 PMCID: PMC7716935 DOI: 10.1007/s12223-020-00810-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/08/2020] [Indexed: 11/26/2022]
Abstract
In this study, a unicellular soil alga isolated from farmland in Germany was surveyed. The investigation of the hypervariable molecular markers ITS1 rDNA and ITS2 rDNA identified strain E71.10 as conspecific with Vischeria sp. SAG 51.91 (Eustigmatophyceae). The culture was tested for biomass generation and for the yield of fatty acids and amino acids. The survey included four different culture conditions (conventional, elevated CO2, nitrogen depletion, or sodium chloride stress) at room temperature. The best yield of dry biomass was achieved applying 1% CO2, whereas nitrogen-free medium resulted into least growth. The fatty acid content peaked in nitrogen-free medium at 59% per dry mass. Eicosapentaenoic acid was the most abundant fatty acid in all treatments (except for nitrogen free), accounting for 10.44 to 16.72 g/100 g dry mass. The highest content of amino acids (20%) was achieved under conventional conditions. The results show that abiotic factors strongly influence to which extent metabolites are intracellularly stored and they confirm also for this yet undescribed strain of Vischeria that Eustigmatophyceae are promising candidates for biotechnology.
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Affiliation(s)
- Daniel Remias
- School of Engineering, University of Applied Sciences Upper Austria, 4600, Wels, Austria.
| | - Cecilia Nicoletti
- School of Engineering, University of Applied Sciences Upper Austria, 4600, Wels, Austria
| | - Klaus Krennhuber
- School of Engineering, University of Applied Sciences Upper Austria, 4600, Wels, Austria
| | - Bettina Möderndorfer
- School of Engineering, University of Applied Sciences Upper Austria, 4600, Wels, Austria
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, 12843, Prague, Czech Republic
| | - Lenka Procházková
- Department of Ecology, Faculty of Science, Charles University, 12843, Prague, Czech Republic
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17
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Amaral R, Fawley KP, Němcová Y, Ševčíková T, Lukešová A, Fawley MW, Santos LMA, Eliáš M. Toward Modern Classification of Eustigmatophytes, Including the Description of Neomonodaceae Fam. Nov. and Three New Genera 1. JOURNAL OF PHYCOLOGY 2020; 56:630-648. [PMID: 32068883 PMCID: PMC7987219 DOI: 10.1111/jpy.12980] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 12/04/2019] [Indexed: 05/09/2023]
Abstract
The class Eustigmatophyceae includes mostly coccoid, freshwater algae, although some genera are common in terrestrial habitats and two are primarily marine. The formal classification of the class, developed decades ago, does not fit the diversity and phylogeny of the group as presently known and is in urgent need of revision. This study concerns a clade informally known as the Pseudellipsoidion group of the order Eustigmatales, which was initially known to comprise seven strains with oval to ellipsoidal cells, some bearing a stipe. We examined those strains as well as 10 new ones and obtained 18S rDNA and rbcL gene sequences. The results from phylogenetic analyses of the sequence data were integrated with morphological data of vegetative and motile cells. Monophyly of the Pseudellipsoidion group is supported in both 18S rDNA and rbcL trees. The group is formalized as the new family Neomonodaceae comprising, in addition to Pseudellipsoidion, three newly erected genera. By establishing Neomonodus gen. nov. (with type species Neomonodus ovalis comb. nov.), we finally resolve the intricate taxonomic history of a species originally described as Monodus ovalis and later moved to the genera Characiopsis and Pseudocharaciopsis. Characiopsiella gen. nov. (with the type species Characiopsiella minima comb. nov.) and Munda gen. nov. (with the type species Munda aquilonaris) are established to accommodate additional representatives of the polyphyletic genus Characiopsis. A morphological feature common to all examined Neomonodaceae is the absence of a pyrenoid in the chloroplasts, which discriminates them from other morphologically similar yet unrelated eustigmatophytes (including other Characiopsis-like species).
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Affiliation(s)
- Raquel Amaral
- Authors for correspondence: Raquel Amaral – , Tel.: +351 962367485; Marek Eliáš – , Tel.: +420 597 092 329
| | - Karen P. Fawley
- Division of Science and Mathematics, University of the Ozarks, Clarksville, Arkansas, 72830, USA
| | - Yvonne Němcová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, 128 01, Prague 2, Czech Republic
| | - Tereza Ševčíková
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Alena Lukešová
- Institute of Soil Biology, Biology Centre, Czech Academy of Sciences, Na Sádkách 7, 370 05 České Budějovice, Czech Republic
| | - Marvin W. Fawley
- Division of Science and Mathematics, University of the Ozarks, Clarksville, Arkansas, 72830, USA
| | - Lília M. A. Santos
- Coimbra Collection of Algae (ACOI), Department of Life Sciences, University of Coimbra, 3000-456, Coimbra, Portugal
| | - Marek Eliáš
- Authors for correspondence: Raquel Amaral – , Tel.: +351 962367485; Marek Eliáš – , Tel.: +420 597 092 329
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18
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Graf L, Yang EC, Boo GH, Andersen RA, Yoon HS. Further investigations on the phaeothamniophyceae using a multigene phylogeny, with descriptions of five new species. JOURNAL OF PHYCOLOGY 2020; 56:358-379. [PMID: 31762049 DOI: 10.1111/jpy.12950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/02/2019] [Indexed: 06/10/2023]
Abstract
We examined 12 strains representing eight species classified in the algal class Phaeothamniophyceae (Heterokontophyta). Based upon a five-gene molecular phylogeny (nuclear-encoded SSU rRNA and plastid-encoded psaA, psbA, psbC, and rbcL) and light microscopic observations, we describe five new species: Phaeoschizochlamys santosii sp. nov., Phaeoschizochlamys siveri sp. nov., Phaeothamnion wetherbeei sp. nov., Stichogloea dopii sp. nov. and Stichogloea fawleyi sp. nov. The Phaeothamniophyceae, as delimited here, form a natural group that is sister to the Aurearenophyceae. Molecular phylogenetic analyses proved more reliable than morphological characters for distinguishing species. Evolutionary trends with the SI clade of the heterokont algae are discussed.
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Affiliation(s)
- Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Eun Chan Yang
- Marine Ecosystem Research Center, Korea Institute of Ocean Science and Technology, Busan, 49111, Korea
| | - Ga Hun Boo
- Department of Biology, Chungnam National University, Daejeon, 34134, Korea
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, 98250, USA
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
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19
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Remias D, Procházková L, Nedbalová L, Andersen RA, Valentin K. Two New Kremastochrysopsis species, K. austriaca sp. nov. and K. americana sp. nov. (Chrysophyceae) 1. JOURNAL OF PHYCOLOGY 2020; 56:135-145. [PMID: 31639884 PMCID: PMC7054049 DOI: 10.1111/jpy.12937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 09/10/2019] [Indexed: 05/20/2023]
Abstract
Melting summer snow in the Austrian Alps exhibited a yellowish bloom that was mainly comprised of an unidentified unicellular chrysophyte. Molecular data (18S rRNA and rbcL genes) showed a close relationship to published sequences from an American pond alga formerly identified as Kremastochrysis sp. The genera Kremastochrysis and Kremastochrysopsis are morphologically distinguished by the number of flagella observed with the light microscope, and therefore we assigned the Austrian snow alga and an American pond alga to the genus Kremastochrysopsis. Transmission and scanning electron microscopy revealed that swimming cells had two flagella oriented in opposite directions, typical for the Hibberdiales. Molecular phylogenetic analyses showed that both new species were closely related to Hibberdia. Kremastochrysopsis ocellata, the type species and only known species, has two chloroplasts per cell and the zoospores have red eyespots. Our two organisms had only a single chloroplast and no zoospore eyespot, but their gene sequences differed substantially. Therefore, we described two new species, Kremastochrysopsis austriaca sp. nov and Kremstochrysopsis americana sp. nov. When grown in culture, both taxa showed a characteristic hyponeustonic growth (hanging below the water surface), whereas older immotile cells grew at the bottom of the culture vessel. Ecologically, Kremastochrysopsis austriaca sp. nov., which caused snow discolorations, had no close phylogenetic relationships to other psychrophilic chrysophytes, for example, Chromulina chionophilia, Hydrurus sp., and Ochromonas-like flagellates.
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Affiliation(s)
- Daniel Remias
- School of EngineeringUniversity of Applied Sciences Upper Austria4600WelsAustria
| | - Lenka Procházková
- Department of EcologyFaculty of ScienceCharles University12844PragueCzech Republic
| | - Linda Nedbalová
- Department of EcologyFaculty of ScienceCharles University12844PragueCzech Republic
| | - Robert A. Andersen
- Friday Harbor LaboratoriesUniversity of WashingtonFriday HarborWashingtonDC98250USA
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20
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Han KY, Maciszewski K, Graf L, Yang JH, Andersen RA, Karnkowska A, Yoon HS. Dictyochophyceae Plastid Genomes Reveal Unusual Variability in Their Organization. JOURNAL OF PHYCOLOGY 2019; 55:1166-1180. [PMID: 31325913 DOI: 10.1111/jpy.12904] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/01/2019] [Indexed: 05/22/2023]
Abstract
Dictyochophyceae (silicoflagellates) are unicellular freshwater and marine algae (Heterokontophyta, stramenopiles). Despite their abundance in global oceans and potential ecological significance, discovered in recent years, neither nuclear nor organellar genomes of representatives of this group were sequenced until now. Here, we present the first complete plastid genome sequences of Dictyochophyceae, obtained from four species: Dictyocha speculum, Rhizochromulina marina, Florenciella parvula and Pseudopedinella elastica. Despite their comparable size and genetic content, these four plastid genomes exhibit variability in their organization: plastid genomes of F. parvula and P. elastica possess conventional quadripartite structure with a pair of inverted repeats, R. marina instead possesses two direct repeats with the same orientation and D. speculum possesses no repeats at all. We also observed a number of unusual traits in the plastid genome of D. speculum, including expansion of the intergenic regions, presence of an intron in the otherwise non-intron-bearing psaA gene, and an additional copy of the large subunit of RuBisCO gene (rbcL), the last of which has never been observed in any plastid genome. We conclude that despite noticeable gene content similarities between the plastid genomes of Dictyochophyceae and their relatives (pelagophytes, diatoms), the number of distinctive features observed in this lineage strongly suggests that additional taxa require further investigation.
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Affiliation(s)
- Kwi Young Han
- Department of Biological Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Kacper Maciszewski
- Department of Molecular Phylogenetics and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Louis Graf
- Department of Biological Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Ji Hyun Yang
- Department of Biological Science, Sungkyunkwan University, Suwon, 16419, Korea
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, 98250, USA
| | - Anna Karnkowska
- Department of Molecular Phylogenetics and Evolution, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089, Warsaw, Poland
| | - Hwan Su Yoon
- Department of Biological Science, Sungkyunkwan University, Suwon, 16419, Korea
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21
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Wetherbee R, Jackson CJ, Repetti SI, Clementson LA, Costa JF, van de Meene A, Crawford S, Verbruggen H. The golden paradox - a new heterokont lineage with chloroplasts surrounded by two membranes. JOURNAL OF PHYCOLOGY 2019; 55:257-278. [PMID: 30536815 DOI: 10.1111/jpy.12822] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
A marine, sand-dwelling, golden-brown alga is described from clonal cultures established from a high intertidal pool in southeastern Australia. This tiny, unicellular species, which we call the "golden paradox" (Chrysoparadoxa australica gen. et sp. nov.), is benthic, surrounded by a multilayered cell wall and attached to the substratum by a complex adhesive plug. Each vegetative cell gives rise to a single, naked zoospore with heterokont flagella that settles and may become briefly amoeboid prior to dividing. Daughter cells are initially amoeboid, then either permanently attach and return to the benthic stage or become motile again prior to final settlement. Two deeply lobed chloroplasts occupy opposite ends of the cell and are surrounded by only two membranes. The outer chloroplast membrane is continuous between the two chloroplasts via the outer membrane of the nuclear envelope. Only two membranes occupy the chloroplast-nucleus interface, the inner membrane of the nuclear envelope and the inner chloroplast membrane. A small pyrenoid is found in each chloroplast and closely abuts the nucleus or protrudes into it. It contains an unusual, membrane-bound inclusion that stains with SYBR green but is unlikely to be a nucleomorph. Phylogenies inferred from a 10-gene concatenated alignment show an early-branching position within the PX clade. The unusual morphological features and phylogenetic position indicate C. australica should be classified as a new class, Chrysoparadoxophyceae. Despite an atypical plastid, exploration of the C. australica transcriptome revealed typical heterokont protein targeting to the plastid.
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Affiliation(s)
- Richard Wetherbee
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Christopher J Jackson
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Sonja I Repetti
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | | | - Joana F Costa
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Allison van de Meene
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Simon Crawford
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
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22
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Ševcíková T, Yurchenko T, Fawley KP, Amaral R, Strnad H, Santos LMA, Fawley MW, Eliáš M. Plastid Genomes and Proteins Illuminate the Evolution of Eustigmatophyte Algae and Their Bacterial Endosymbionts. Genome Biol Evol 2019; 11:362-379. [PMID: 30629162 PMCID: PMC6367104 DOI: 10.1093/gbe/evz004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2019] [Indexed: 12/26/2022] Open
Abstract
Eustigmatophytes, a class of stramenopile algae (ochrophytes), include not only the extensively studied biotechnologically important genus Nannochloropsis but also a rapidly expanding diversity of lineages with much less well characterized biology. Recent discoveries have led to exciting additions to our knowledge about eustigmatophytes. Some proved to harbor bacterial endosymbionts representing a novel genus, Candidatus Phycorickettsia, and an operon of unclear function (ebo) obtained by horizontal gene transfer from the endosymbiont lineage was found in the plastid genomes of still other eustigmatophytes. To shed more light on the latter event, as well as to generally improve our understanding of the eustigmatophyte evolutionary history, we sequenced plastid genomes of seven phylogenetically diverse representatives (including new isolates representing undescribed taxa). A phylogenomic analysis of plastid genome-encoded proteins resolved the phylogenetic relationships among the main eustigmatophyte lineages and provided a framework for the interpretation of plastid gene gains and losses in the group. The ebo operon gain was inferred to have probably occurred within the order Eustigmatales, after the divergence of the two basalmost lineages (a newly discovered hitherto undescribed strain and the Pseudellipsoidion group). When looking for nuclear genes potentially compensating for plastid gene losses, we noticed a gene for a plastid-targeted acyl carrier protein that was apparently acquired by horizontal gene transfer from Phycorickettsia. The presence of this gene in all eustigmatophytes studied, including representatives of both principal clades (Eustigmatales and Goniochloridales), is a genetic footprint indicating that the eustigmatophyte-Phycorickettsia partnership started no later than in the last eustigmatophyte common ancestor.
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Affiliation(s)
- Tereza Ševcíková
- Department of Biology and Ecology Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Tatiana Yurchenko
- Faculty of Science, Institute of Environmental Technologies, University of Ostrava, Ostrava, Czech Republic
| | - Karen P Fawley
- Division of Sciences and Mathematics, University of the Ozarks, Clarksville, Arkansas
| | - Raquel Amaral
- Coimbra Collection of Algae (ACOI), Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Hynek Strnad
- Laboratory of Genomics and Bioinformatics, Institute of Molecular Genetics of the CAS, v.v.i., Prague, Czech Republic
| | - Lilia M A Santos
- Coimbra Collection of Algae (ACOI), Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Marvin W Fawley
- Division of Sciences and Mathematics, University of the Ozarks, Clarksville, Arkansas.,School of Mathematical and Natural Sciences, University of Arkansas at Monticello, Monticello, Arkansas
| | - Marek Eliáš
- Department of Biology and Ecology Faculty of Science, University of Ostrava, Ostrava, Czech Republic.,Faculty of Science, Institute of Environmental Technologies, University of Ostrava, Ostrava, Czech Republic
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Kim JI, Shin H, Škaloud P, Jung J, Yoon HS, Archibald JM, Shin W. Comparative plastid genomics of Synurophyceae: inverted repeat dynamics and gene content variation. BMC Evol Biol 2019; 19:20. [PMID: 30634905 PMCID: PMC6330437 DOI: 10.1186/s12862-018-1316-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 12/04/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Synurophyceae is one of most important photosynthetic stramenopile algal lineages in freshwater ecosystems. They are characterized by siliceous scales covering the cell or colony surface and possess plastids of red-algal secondary or tertiary endosymbiotic origin. Despite their ecological and evolutionary significance, the relationships amongst extant Synurophyceae are unclear, as is their relationship to most other stramenopiles. RESULTS Here we report a comparative analysis of plastid genomes sequenced from five representative synurophycean algae. Most of these plastid genomes are highly conserved with respect to genome structure and coding capacity, with the exception of gene re-arrangements and partial duplications at the boundary of the inverted repeat and single-copy regions. Several lineage-specific gene loss/gain events and intron insertions were detected (e.g., cemA, dnaB, syfB, and trnL). CONCLUSIONS Unexpectedly, the cemA gene of Synurophyceae shows a strong relationship with sequences from members of the green-algal lineage, suggesting the occurrence of a lateral gene transfer event. Using a molecular clock approach based on silica fossil record data, we infer the timing of genome re-arrangement and gene gain/loss events in the plastid genomes of Synurophyceae.
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Affiliation(s)
- Jong Im Kim
- Department of Biology, Chungnam National University, Daejeon, 34134, South Korea
| | - Hyunmoon Shin
- Department of Biology, Chungnam National University, Daejeon, 34134, South Korea
| | - Pavel Škaloud
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-12800, Prague 2, Czech Republic
| | - Jaehee Jung
- Department of General Education, Hongik University, Seoul, 04066, South Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, South Korea
| | - John M Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Woongghi Shin
- Department of Biology, Chungnam National University, Daejeon, 34134, South Korea.
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24
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Stoykova P, Stoyneva-Gärtner M, Uzunov B, Gärtner G, Atanassov I, Draganova P, Borisova C. Morphological characterization and phylogenetic analysis of aeroterrestrial Vischeria/Eustigmatos strains with industrial potential. BIOTECHNOL BIOTEC EQ 2019. [DOI: 10.1080/13102818.2018.1561212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Petya Stoykova
- Plant Genetics Group, AgroBioInstitute, Agricultural Academy, Sofia, Bulgaria
| | - Maya Stoyneva-Gärtner
- Department of Botany, Faculty of Biology, Sofia University “St Kliment Ohridski”, Sofia, Bulgaria
| | - Blagoy Uzunov
- Department of Botany, Faculty of Biology, Sofia University “St Kliment Ohridski”, Sofia, Bulgaria
| | - Georg Gärtner
- Institut für Botanik, Fakultät für Biologie, Üniversitat Innsbruck, Austria
| | - Ivan Atanassov
- Plant Genetics Group, AgroBioInstitute, Agricultural Academy, Sofia, Bulgaria
| | - Petya Draganova
- Department of Botany, Faculty of Biology, Sofia University “St Kliment Ohridski”, Sofia, Bulgaria
| | - Cvetanka Borisova
- Department of Botany, Faculty of Biology, Sofia University “St Kliment Ohridski”, Sofia, Bulgaria
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25
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Liu F, Zhang Y, Bi Y, Chen W, Moejes FW. Understanding the Evolution of Mitochondrial Genomes in Phaeophyceae Inferred from Mitogenomes of Ishige okamurae (Ishigeales) and Dictyopteris divaricata (Dictyotales). J Mol Evol 2019; 87:16-26. [PMID: 30604018 DOI: 10.1007/s00239-018-9881-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 12/15/2018] [Indexed: 11/29/2022]
Abstract
To gain further insight into the evolution of mitochondrial genomes (mtDNAs) in Phaeophyceae, the first recorded characterization of an Ishigeophycidae mtDNA from Ishige okamurae (Yendo), and only the second recorded characterization of a Dictyotophycidae mtDNA from Dictyopteris divaricata (Okamura) Okamura are presented in this study. The 35,485 bp I. okamurae mtDNA contained 36 protein-coding genes (PCGs), 22 tRNAs, three rRNAs, and four open reading frames (orfs), and the 32,021 bp D. divaricata mtDNA harbored 35 PCGs, 25 tRNAs, three rRNAs, and three orfs. The A + T content in D. divaricata (61.69%) was the lowest recorded in sequenced brown algal mtDNAs. The I. okamurae mtDNA displayed unique genome features including an elevated start-codon usage bias for GTG, while the organization of D. divaricata mtDNA was identical to that of Dictyota dichotoma. Phylogenetic analysis based on the amino acid sequence dataset of 35 PCGs indicated that I. okamurae (Ishigeophycidae) diverged early from the Fucophycidae-Dictyotophycidae complex, which was confirmed by the comparative analysis of the mitogenome structure. The novel mitogenome data made available by this study have improved our understanding of the evolution, phylogenetics, and genomics of brown algae.
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Affiliation(s)
- Feng Liu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, Shandong, People's Republic of China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, Shandong, People's Republic of China.
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, Shandong, People's Republic of China.
| | - Yongyu Zhang
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, People's Republic of China
| | - Yuping Bi
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan, 250100, Shandong, People's Republic of China
| | - Weizhou Chen
- Marine Biology Institute, Shantou University, Shantou, 515063, Guangdong, People's Republic of China
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26
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Elkhouni A, Rabhi M, Ivanov AG, Krol M, Zorrig W, Smaoui A, Abdelly C, Huner NPA. Structural and functional integrity of Sulla carnosa photosynthetic apparatus under iron deficiency conditions. PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:415-425. [PMID: 29274120 DOI: 10.1111/plb.12684] [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: 11/06/2017] [Accepted: 12/15/2017] [Indexed: 06/07/2023]
Abstract
The abundance of calcareous soils makes bicarbonate-induced iron (Fe) deficiency a major problem for plant growth and crop yield. Therefore, Fe-efficient plants may constitute a solution for use on calcareous soils. We investigated the ability of the forage legume Sulla carnosa (Desf.) to maintain integrity of its photosynthetic apparatus under Fe deficiency conditions. Three treatments were applied: control, direct Fe deficiency and bicarbonate-induced Fe deficiency. At harvest, all organs of deficient plants showed severe growth inhibition, the effect being less pronounced under indirect Fe deficiency. Pigment analysis of fully expanded leaves revealed a reduction in concentrations of chlorophyll a, chlorophyll b and carotenoids under Fe deficiency. Electron transport rate, maximum and effective quantum yield of photosystem II (PSII), photochemical quenching (qP), non-photochemical quenching (qN) as well as P700 activity also decreased significantly in plants exposed to direct Fe deficiency, while qN was not affected. The effects of indirect Fe deficiency on the same parameters were less pronounced in bicarbonate-treated plants. The relative abundances of thylakoid proteins related to PSI (PsaA, Lhca1, Lhca2) and PSII (PsbA, Lhcb1) were also more affected under direct than indirect Fe deficiency. We conclude that S. carnosa can maintain the integrity of its photosynthetic apparatus under bicarbonate-induced Fe deficiency, preventing harmful effects to both photosystems under direct Fe deficiency. This suggests a high capacity of this species not only to take up Fe in the presence of bicarbonate (HCO3- ) but also to preferentially translocate absorbed Fe towards leaves and prevent its inactivation.
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Affiliation(s)
- A Elkhouni
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - M Rabhi
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - A G Ivanov
- Department of Biology, University of Western Ontario, London, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - M Krol
- Department of Biology, University of Western Ontario, London, Canada
| | - W Zorrig
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - A Smaoui
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - C Abdelly
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, Hammam-Lif, Tunisia
| | - N P A Huner
- Department of Biology, University of Western Ontario, London, Canada
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27
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Han KY, Graf L, Reyes CP, Melkonian B, Andersen RA, Yoon HS, Melkonian M. A Re-investigation of Sarcinochrysis marina (Sarcinochrysidales, Pelagophyceae) from its Type Locality and the Descriptions of Arachnochrysis , Pelagospilus, Sargassococcus and Sungminbooa genera nov. Protist 2018; 169:79-106. [DOI: 10.1016/j.protis.2017.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/15/2017] [Accepted: 12/15/2017] [Indexed: 11/26/2022]
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Graf L, Kim YJ, Cho GY, Miller KA, Yoon HS. Plastid and mitochondrial genomes of Coccophora langsdorfii (Fucales, Phaeophyceae) and the utility of molecular markers. PLoS One 2017; 12:e0187104. [PMID: 29095864 PMCID: PMC5695614 DOI: 10.1371/journal.pone.0187104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 10/15/2017] [Indexed: 11/29/2022] Open
Abstract
Coccophora langsdorfii (Turner) Greville (Fucales) is an intertidal brown alga that is endemic to Northeast Asia and increasingly endangered by habitat loss and climate change. We sequenced the complete circular plastid and mitochondrial genomes of C. langsdorfii. The circular plastid genome is 124,450 bp and contains 139 protein-coding, 28 tRNA and 6 rRNA genes. The circular mitochondrial genome is 35,660 bp and contains 38 protein-coding, 25 tRNA and 3 rRNA genes. The structure and gene content of the C. langsdorfii plastid genome is similar to those of other species in the Fucales. The plastid genomes of brown algae in other orders share similar gene content but exhibit large structural recombination. The large in-frame insert in the cox2 gene in the mitochondrial genome of C. langsdorfii is typical of other brown algae. We explored the effect of this insertion on the structure and function of the cox2 protein. We estimated the usefulness of 135 plastid genes and 35 mitochondrial genes for developing molecular markers. This study shows that 29 organellar genes will prove efficient for resolving brown algal phylogeny. In addition, we propose a new molecular marker suitable for the study of intraspecific genetic diversity that should be tested in a large survey of populations of C. langsdorfii.
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Affiliation(s)
- Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
| | - Yae Jin Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
| | - Ga Youn Cho
- National Institute of Biological Resources, Incheon, Korea
| | - Kathy Ann Miller
- University Herbarium, University of California, Berkeley, CA, United States of America
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea
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29
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Wang Q, Sun H, Huang J. Re-analyses of "Algal" Genes Suggest a Complex Evolutionary History of Oomycetes. FRONTIERS IN PLANT SCIENCE 2017; 8:1540. [PMID: 28932232 PMCID: PMC5592239 DOI: 10.3389/fpls.2017.01540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/22/2017] [Indexed: 06/07/2023]
Abstract
The spread of photosynthesis is one of the most important but constantly debated topics in eukaryotic evolution. Various hypotheses have been proposed to explain the plastid distribution in extant eukaryotes. Notably, the chromalveolate hypothesis suggested that multiple eukaryotic lineages were derived from a photosynthetic ancestor that had a red algal endosymbiont. As such, genes of plastid/algal origin in aplastidic chromalveolates, such as oomycetes, were considered to be important supporting evidence. Although the chromalveolate hypothesis has been seriously challenged, some of its supporting evidence has not been carefully investigated. In this study, we re-evaluate the "algal" genes from oomycetes with a larger sampling and careful phylogenetic analyses. Our data provide no conclusive support for a common photosynthetic ancestry of stramenopiles, but show that the initial estimate of "algal" genes in oomycetes was drastically inflated due to limited genome data available then for certain eukaryotic lineages. These findings also suggest that the evolutionary histories of these "algal" genes might be attributed to complex scenarios such as differential gene loss, serial endosymbioses, or horizontal gene transfer.
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Affiliation(s)
- Qia Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- University of Chinese Academy of SciencesBeijing, China
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Jinling Huang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- State Key Laboratory of Cotton Biology, Institute of Plant Stress Biology, Henan UniversityKaifeng, China
- Department of Biology, East Carolina University, GreenvilleNC, United States
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30
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Raven JA, Giordano M. Acquisition and metabolism of carbon in the Ochrophyta other than diatoms. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160400. [PMID: 28717026 PMCID: PMC5516109 DOI: 10.1098/rstb.2016.0400] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2017] [Indexed: 11/12/2022] Open
Abstract
The acquisition and assimilation of inorganic C have been investigated in several of the 15 clades of the Ochrophyta other than diatoms, with biochemical, physiological and genomic data indicating significant mechanistic variation. Form ID Rubiscos in the Ochrophyta are characterized by a broad range of kinetics values. In spite of relatively high K0.5CO2 and low CO2 : O2 selectivity, diffusive entry of CO2 occurs in the Chrysophyceae and Synurophyceae. Eustigmatophyceae and Phaeophyceae, on the contrary, have CO2 concentrating mechanisms, usually involving the direct or indirect use of [Formula: see text] This variability is possibly due to the ecological contexts of the organism. In brown algae, C fixation generally takes place through a classical C3 metabolism, but there are some hints of the occurrence of C4 metabolism and low amplitude CAM in a few members of the Fucales. Genomic data show the presence of a number of potential C4 and CAM genes in Ochrophyta other than diatoms, but the other core functions of many of these genes give a very limited diagnostic value to their presence and are insufficient to conclude that C4 photosynthesis is present in these algae.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Mario Giordano
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona 60131, Italy
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Trěboň 37901, Czech Republic
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31
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Basu S, Patil S, Mapleson D, Russo MT, Vitale L, Fevola C, Maumus F, Casotti R, Mock T, Caccamo M, Montresor M, Sanges R, Ferrante MI. Finding a partner in the ocean: molecular and evolutionary bases of the response to sexual cues in a planktonic diatom. THE NEW PHYTOLOGIST 2017; 215:140-156. [PMID: 28429538 PMCID: PMC5485032 DOI: 10.1111/nph.14557] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 02/25/2017] [Indexed: 05/03/2023]
Abstract
Microalgae play a major role as primary producers in aquatic ecosystems. Cell signalling regulates their interactions with the environment and other organisms, yet this process in phytoplankton is poorly defined. Using the marine planktonic diatom Pseudo-nitzschia multistriata, we investigated the cell response to cues released during sexual reproduction, an event that demands strong regulatory mechanisms and impacts on population dynamics. We sequenced the genome of P. multistriata and performed phylogenomic and transcriptomic analyses, which allowed the definition of gene gains and losses, horizontal gene transfers, conservation and evolutionary rate of sex-related genes. We also identified a small number of conserved noncoding elements. Sexual reproduction impacted on cell cycle progression and induced an asymmetric response of the opposite mating types. G protein-coupled receptors and cyclic guanosine monophosphate (cGMP) are implicated in the response to sexual cues, which overall entails a modulation of cell cycle, meiosis-related and nutrient transporter genes, suggesting a fine control of nutrient uptake even under nutrient-replete conditions. The controllable life cycle and the genome sequence of P. multistriata allow the reconstruction of changes occurring in diatoms in a key phase of their life cycle, providing hints on the evolution and putative function of their genes and empowering studies on sexual reproduction.
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Affiliation(s)
- Swaraj Basu
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | - Shrikant Patil
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | | | - Monia Teresa Russo
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | - Laura Vitale
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | - Cristina Fevola
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | | | - Raffaella Casotti
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | - Thomas Mock
- School of Environmental SciencesUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Mario Caccamo
- Earlham InstituteNorwich Research ParkNorwichNR4 7UGUK
| | - Marina Montresor
- Integrative Marine EcologyStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
| | - Remo Sanges
- Biology and Evolution of Marine OrganismsStazione Zoologica Anton DohrnVilla Comunale 1Naples80121Italy
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Raven JA, Beardall J, Sánchez-Baracaldo P. The possible evolution and future of CO2-concentrating mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3701-3716. [PMID: 28505361 DOI: 10.1093/jxb/erx110] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
CO2-concentrating mechanisms (CCMs), based either on active transport of inorganic carbon (biophysical CCMs) or on biochemistry involving supplementary carbon fixation into C4 acids (C4 and CAM), play a major role in global primary productivity. However, the ubiquitous CO2-fixing enzyme in autotrophs, Rubisco, evolved at a time when atmospheric CO2 levels were very much higher than today and O2 was very low and, as CO2 and O2 approached (by no means monotonically), today's levels, at some time subsequently many organisms evolved a CCM that increased the supply of CO2 and decreased Rubisco oxygenase activity. Given that CO2 levels and other environmental factors have altered considerably between when autotrophs evolved and the present day, and are predicted to continue to change into the future, we here examine the drivers for, and possible timing of, evolution of CCMs. CCMs probably evolved when CO2 fell to 2-16 times the present atmospheric level, depending on Rubisco kinetics. We also assess the effects of other key environmental factors such as temperature and nutrient levels on CCM activity and examine the evidence for evolutionary changes in CCM activity and related cellular processes as well as limitations on continuity of CCMs through environmental variations.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- Functional Plant Biology and Climate Change Cluster, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Building 18, Clayton Campus, Vic 3800, Australia
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Dorrell RG, Gile G, McCallum G, Méheust R, Bapteste EP, Klinger CM, Brillet-Guéguen L, Freeman KD, Richter DJ, Bowler C. Chimeric origins of ochrophytes and haptophytes revealed through an ancient plastid proteome. eLife 2017; 6. [PMID: 28498102 PMCID: PMC5462543 DOI: 10.7554/elife.23717] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 05/08/2017] [Indexed: 12/18/2022] Open
Abstract
Plastids are supported by a wide range of proteins encoded within the nucleus and imported from the cytoplasm. These plastid-targeted proteins may originate from the endosymbiont, the host, or other sources entirely. Here, we identify and characterise 770 plastid-targeted proteins that are conserved across the ochrophytes, a major group of algae including diatoms, pelagophytes and kelps, that possess plastids derived from red algae. We show that the ancestral ochrophyte plastid proteome was an evolutionary chimera, with 25% of its phylogenetically tractable nucleus-encoded proteins deriving from green algae. We additionally show that functional mixing of host and plastid proteomes, such as through dual-targeting, is an ancestral feature of plastid evolution. Finally, we detect a clear phylogenetic signal from one ochrophyte subgroup, the lineage containing pelagophytes and dictyochophytes, in plastid-targeted proteins from another major algal lineage, the haptophytes. This may represent a possible serial endosymbiosis event deep in eukaryotic evolutionary history. DOI:http://dx.doi.org/10.7554/eLife.23717.001 The cells of most plants and algae contain compartments called chloroplasts that enable them to capture energy from sunlight in a process known as photosynthesis. Chloroplasts are the remnants of photosynthetic bacteria that used to live freely in the environment until they were consumed by a larger cell. “Complex” chloroplasts can form if a cell that already has a chloroplast is swallowed by another cell. The most abundant algae in the oceans are known as diatoms. These algae belong to a group called the stramenopiles, which also includes giant seaweeds such as kelp. The stramenopiles have a complex chloroplast that they acquired from a red alga (a relative of the seaweed used in sushi). However, some of the proteins in their chloroplasts are from other sources, such as the green algal relatives of plants, and it was not clear how these chloroplast proteins have contributed to the evolution of this group. Many of the proteins that chloroplasts need to work properly are produced by the host cell and are then transported into the chloroplasts. Dorrell et al. studied the genetic material of many stramenopile species and identified 770 chloroplast-targeted proteins that are predicted to underpin the origins of this group. Experiments in a diatom called Phaeodactylum confirmed these predictions and show that many of these chloroplast-targeted proteins have been recruited from green algae, bacteria, and other compartments within the host cell to support the chloroplast. Further experiments suggest that another major group of algae called the haptophytes once had a stramenopile chloroplast. The current haptophyte chloroplast does not come from the stramenopiles so the haptophytes appear to have replaced their chloroplasts at least once in their evolutionary history. The findings show that algal chloroplasts are mosaics, supported by proteins from many different species. This helps us understand why certain species succeed in the wild and how they may respond to environmental changes in the oceans. In the future, these findings may help researchers to engineer new species of algae and plants for food and fuel production. DOI:http://dx.doi.org/10.7554/eLife.23717.002
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Affiliation(s)
- Richard G Dorrell
- IBENS, Département de Biologie, École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
| | - Gillian Gile
- School of Life Sciences, Arizona State University, Tempe, United States
| | - Giselle McCallum
- IBENS, Département de Biologie, École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
| | - Raphaël Méheust
- Institut de Biologie Paris-Seine, Université Pierre et Marie Curie, Paris, France
| | - Eric P Bapteste
- Institut de Biologie Paris-Seine, Université Pierre et Marie Curie, Paris, France
| | | | | | | | - Daniel J Richter
- Sorbonne Universités, Université Pierre et Marie Curie, CNRS UMR 7144.,Adaptation et Diversité en Milieu Marin, Équipe EPEP, Station Biologique de Roscoff, Roscoff, France
| | - Chris Bowler
- IBENS, Département de Biologie, École Normale Supérieure, CNRS, Inserm, PSL Research University, Paris, France
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34
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Review of the algal biology program within the National Alliance for Advanced Biofuels and Bioproducts. ALGAL RES 2017. [DOI: 10.1016/j.algal.2016.06.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Yamada K, Nagasato C, Motomura T, Ichinomiya M, Kuwata A, Kamiya M, Ohki K, Yoshikawa S. Mitotic spindle formation in Triparma laevis NIES-2565(Parmales, Heterokontophyta). PROTOPLASMA 2017; 254:461-471. [PMID: 27048177 DOI: 10.1007/s00709-016-0967-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 03/23/2016] [Indexed: 06/05/2023]
Abstract
The parmalean algae possess a siliceous wall and represent the sister lineage of diatoms; they are thought to be a key group for understanding the evolution of diatoms. Diatoms possess well-characterized and unique mitotic structures, but the mitotic apparatus of Parmales is still unknown. We observed the microtubule (MT) array during interphase and mitosis in Triparma laevis using TEM. The interphase cells had four or five centrioles (∼80 nm in length), from which MTs emanated toward the cytoplasm. In prophase, the bundle of MTs arose at an extranuclear site. The position of centrioles with respect to an MT bundle changed during its elongation. Centrioles were observed on the lateral side of a shorter MT bundle (∼590 nm) and on either side of an extended MT bundle (∼700 nm). In metaphase, the spindle consisted of two types of MTs-MT bundle that passed through a cytoplasmic tunnel in the center of the nucleus and single MTs (possibly kinetochore MTs) that extended from the poles into the nucleus. The nuclear envelope disappeared only at the regions where the kinetochore MTs penetrated. In telophase, daughter chromosomes migrated toward opposite poles, and the MT bundle was observed between segregating chromosomes. These observations showed that MT nucleation does not always occur at the periphery of centrioles through cell cycle and that the spindle of T. laevis has a similar configuration to that of diatoms.
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Affiliation(s)
- Kazumasa Yamada
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0003, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0003, Japan
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0003, Japan
| | - Mutsuo Ichinomiya
- Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Higashi, 862-8502, Japan
| | - Akira Kuwata
- Tohoku National Fisheries Research Institute, Shiogama, 985-0001, Japan
| | - Mitsunobu Kamiya
- Faculty of Marine Bioscience, Fukui Prefectural University, Obama, 917-0003, Japan
| | - Kaori Ohki
- Faculty of Marine Bioscience, Fukui Prefectural University, Obama, 917-0003, Japan
| | - Shinya Yoshikawa
- Faculty of Marine Bioscience, Fukui Prefectural University, Obama, 917-0003, Japan.
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Derelle R, López-García P, Timpano H, Moreira D. A Phylogenomic Framework to Study the Diversity and Evolution of Stramenopiles (=Heterokonts). Mol Biol Evol 2016; 33:2890-2898. [PMID: 27512113 DOI: 10.1093/molbev/msw168] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Stramenopiles or heterokonts constitute one of the most speciose and diverse clades of protists. It includes ecologically important algae (such as diatoms or large multicellular brown seaweeds), as well as heterotrophic (e.g., bicosoecids, MAST groups) and parasitic (e.g., Blastocystis, oomycetes) species. Despite their evolutionary and ecological relevance, deep phylogenetic relationships among stramenopile groups, inferred mostly from small-subunit rDNA phylogenies, remain unresolved, especially for the heterotrophic taxa. Taking advantage of recently released stramenopile transcriptome and genome sequences, as well as data from the genomic assembly of the MAST-3 species Incisomonas marina generated in our laboratory, we have carried out the first extensive phylogenomic analysis of stramenopiles, including representatives of most major lineages. Our analyses, based on a large data set of 339 widely distributed proteins, strongly support a root of stramenopiles lying between two clades, Bigyra and Gyrista (Pseudofungi plus Ochrophyta). Additionally, our analyses challenge the Phaeista-Khakista dichotomy of photosynthetic stramenopiles (ochrophytes) as two groups previously considered to be part of the Phaeista (Pelagophyceae and Dictyochophyceae), branch with strong support with the Khakista (Bolidophyceae and Diatomeae). We propose a new classification of ochrophytes within the two groups Chrysista and Diatomista to reflect the new phylogenomic results. Our stramenopile phylogeny provides a robust phylogenetic framework to investigate the evolution and diversification of this group of ecologically relevant protists.
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Affiliation(s)
- Romain Derelle
- Unité d'Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud/Paris-Saclay, AgroParisTech, Orsay, France
| | - Purificación López-García
- Unité d'Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud/Paris-Saclay, AgroParisTech, Orsay, France
| | - Hélène Timpano
- Unité d'Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud/Paris-Saclay, AgroParisTech, Orsay, France
| | - David Moreira
- Unité d'Ecologie, Systématique et Evolution, Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud/Paris-Saclay, AgroParisTech, Orsay, France
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Yang JH, Graf L, Cho CH, Jeon BH, Kim JH, Yoon HS. Complete plastid genome of an ecologically important brown alga Sargassum thunbergii (Fucales, Phaeophyceae). Mar Genomics 2016; 28:17-20. [PMID: 27012360 DOI: 10.1016/j.margen.2016.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 11/30/2022]
Abstract
The brown algal species Sargassum thunbergii (Fucales, Phaeophyceae) is widely distributed in coastal area of East Asia. This alga is ecologically and economically important seaweeds; however, no genome data was reported thus far. To get a better understanding of organellar genome of S. thunbergii, we sequenced and annotated its complete plastid genome. The circular plastid genome is 124,592bp in size with 30.4% GC content, which is composed of a large single-copy (LSC) region of 73,668bp, a small single-copy (SSC) region of 40,032bp, and two inverted repeat (IR) of 5446bp each. The plastid genome of S. thunbergii includes 139 protein-coding genes, six ribosomal RNA (rRNA) operons, 28 transfer RNA (tRNA) sequences, and one intron (214bp) in tRNA-Leu (trnL) gene. Five overlapping genes were identified in the compact plastid genome. Base on the comparison with previously published five brown algae plastid genomes, we found that the gene content and gene order of S. thunbergii are identical to that of other Fucales species Fucus vesiculosus.
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Affiliation(s)
- Ji Hyun Yang
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Chung Hyun Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Byung Hee Jeon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jeong Ha Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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Tajima N, Saitoh K, Sato S, Maruyama F, Ichinomiya M, Yoshikawa S, Kurokawa K, Ohta H, Tabata S, Kuwata A, Sato N. Sequencing and analysis of the complete organellar genomes of Parmales, a closely related group to Bacillariophyta (diatoms). Curr Genet 2016; 62:887-896. [DOI: 10.1007/s00294-016-0598-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 03/25/2016] [Accepted: 03/26/2016] [Indexed: 10/21/2022]
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Ševčíková T, Klimeš V, Zbránková V, Strnad H, Hroudová M, Vlček Č, Eliáš M. A Comparative Analysis of Mitochondrial Genomes in Eustigmatophyte Algae. Genome Biol Evol 2016; 8:705-22. [PMID: 26872774 PMCID: PMC4824035 DOI: 10.1093/gbe/evw027] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Eustigmatophyceae (Ochrophyta, Stramenopiles) is a small algal group with species of the genus Nannochloropsis being its best studied representatives. Nuclear and organellar genomes have been recently sequenced for several Nannochloropsis spp., but phylogenetically wider genomic studies are missing for eustigmatophytes. We sequenced mitochondrial genomes (mitogenomes) of three species representing most major eustigmatophyte lineages, Monodopsis sp. MarTras21, Vischeria sp. CAUP Q 202 and Trachydiscus minutus, and carried out their comparative analysis in the context of available data from Nannochloropsis and other stramenopiles, revealing a number of noticeable findings. First, mitogenomes of most eustigmatophytes are highly collinear and similar in the gene content, but extensive rearrangements and loss of three otherwise ubiquitous genes happened in the Vischeria lineage; this correlates with an accelerated evolution of mitochondrial gene sequences in this lineage. Second, eustigmatophytes appear to be the only ochrophyte group with the Atp1 protein encoded by the mitogenome. Third, eustigmatophyte mitogenomes uniquely share a truncated nad11 gene encoding only the C-terminal part of the Nad11 protein, while the N-terminal part is encoded by a separate gene in the nuclear genome. Fourth, UGA as a termination codon and the cognate release factor mRF2 were lost from mitochondria independently by the Nannochloropsis and T. minutus lineages. Finally, the rps3 gene in the mitogenome of Vischeria sp. is interrupted by the UAG codon, but the genome includes a gene for an unusual tRNA with an extended anticodon loop that we speculate may serve as a suppressor tRNA to properly decode the rps3 gene.
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Affiliation(s)
- Tereza Ševčíková
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
| | - Vladimír Klimeš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
| | - Veronika Zbránková
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
| | - Hynek Strnad
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Miluše Hroudová
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Čestmír Vlček
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Marek Eliáš
- Department of Biology and Ecology & Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Czech Republic
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An SM, Kim SY, Noh JH, Yang EC. Complete mitochondrial genome of Skeletonema marinoi (Mediophyceae, Bacillariophyta), a clonal chain forming diatom in the west coast of Korea. Mitochondrial DNA A DNA Mapp Seq Anal 2015; 28:19-20. [PMID: 26641316 DOI: 10.3109/19401736.2015.1106523] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The complete mitochondrial DNA of common planktonic diatom, Skeletonema marinoi JK029 was sequenced and characterized. The circular mitogenome contains 62 genes in 38 515 bp (29.7% GC), including 35 protein-coding, 2 rRNA, and 25 tRNA genes. Total 80% of protein-coding genes have usual ATG start codon and 20% have alternative start codons. The GC content of tRNA genes (39.8%) is relatively higher than those of the rRNA (32.9%) and CDS (29.3%). There are four cases of gene overlapping between neighboring genes, i.e., rrs-trnM, rps2-rps4, nad1-tatC, and rps11-trnY. Newly determined mitogenome of S. marinoi was compared with available seven diatoms and eight stramenopiles by using the maximum-likelihood analysis. The 34-CDS concatenated data (8528 amino acids) support the monophyly of Bacillariophyta. However, mitogenome data showed different higher class-levels clustering with previous study. These results suggested that additional mitogenome data will provide useful information for mitochondrial genome diversity and evolution of the diatoms and stramenopiles.
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Affiliation(s)
- Sung Min An
- a Marine Ecosystem and Biological Research Center, Korea Institute of Ocean Science & Technology , Ansan , Republic of Korea
| | - Soo Yeon Kim
- b Department of Marine Sciences and Convergence Technology , Hanyang University , Ansan , Republic of Korea , and
| | - Jae Hoon Noh
- a Marine Ecosystem and Biological Research Center, Korea Institute of Ocean Science & Technology , Ansan , Republic of Korea
| | - Eun Chan Yang
- a Marine Ecosystem and Biological Research Center, Korea Institute of Ocean Science & Technology , Ansan , Republic of Korea.,c Department of Marine Biology , Korea University of Science and Technology , Daejeon , Republic of Korea
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Cho SM, Jeoung SC, Song JY, Kupriyanova EV, Pronina NA, Lee BW, Jo SW, Park BS, Choi SB, Song JJ, Park YI. Genomic Survey and Biochemical Analysis of Recombinant Candidate Cyanobacteriochromes Reveals Enrichment for Near UV/Violet Sensors in the Halotolerant and Alkaliphilic Cyanobacterium Microcoleus IPPAS B353. J Biol Chem 2015; 290:28502-28514. [PMID: 26405033 DOI: 10.1074/jbc.m115.669150] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Indexed: 11/06/2022] Open
Abstract
Cyanobacteriochromes (CBCRs), which are exclusive to and widespread among cyanobacteria, are photoproteins that sense the entire range of near-UV and visible light. CBCRs are related to the red/far-red phytochromes that utilize linear tetrapyrrole (bilin) chromophores. Best characterized from the unicellular cyanobacterium Synechocystis sp. PCC 6803 and the multicellular heterocyst forming filamentous cyanobacteria Nostoc punctiforme ATCC 29133 and Anabaena sp. PCC 7120, CBCRs have been poorly investigated in mat-forming, nonheterocystous cyanobacteria. In this study, we sequenced the genome of one of such species, Microcoleus IPPAS B353 (Microcoleus B353), and identified two phytochromes and seven CBCRs with one or more bilin-binding cGMP-specific phosphodiesterase, adenylyl cyclase and FhlA (GAF) domains. Biochemical and spectroscopic measurements of 23 purified GAF proteins from phycocyanobilin (PCB) producing recombinant Escherichia coli indicated that 13 of these proteins formed near-UV and visible light-absorbing covalent adducts: 10 GAFs contained PCB chromophores, whereas three contained the PCB isomer, phycoviolobilin (PVB). Furthermore, the complement of Microcoleus B353 CBCRs is enriched in near-UV and violet sensors, but lacks red/green and green/red CBCRs that are widely distributed in other cyanobacteria. We hypothesize that enrichment in short wavelength-absorbing CBCRs is critical for acclimation to high-light environments where this organism is found.
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Affiliation(s)
- Sung Mi Cho
- Department of Biological Sciences, Chungnam National University, Daejeon, 305-764, Korea
| | - Sae Chae Jeoung
- Center for Advanced Measurement and Instrumentation, Korea Research Institute of Standards and Science, Daejeon 305-340, Korea
| | - Ji-Young Song
- Department of Biological Sciences, Chungnam National University, Daejeon, 305-764, Korea
| | - Elena V Kupriyanova
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | - Natalia A Pronina
- Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, Moscow 127276, Russia
| | | | | | - Beom-Seok Park
- The Agricultural Genome Center, National Academy of Agricultural Science, Rural Development Administration, Wanju 565-851, Korea.
| | - Sang-Bong Choi
- School of Biotechnology and Environmental Engineering, Myongji University, Yongin 449-728, Korea
| | - Ji-Joon Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea
| | - Youn-Il Park
- Department of Biological Sciences, Chungnam National University, Daejeon, 305-764, Korea
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Ševčíková T, Horák A, Klimeš V, Zbránková V, Demir-Hilton E, Sudek S, Jenkins J, Schmutz J, Přibyl P, Fousek J, Vlček Č, Lang BF, Oborník M, Worden AZ, Eliáš M. Updating algal evolutionary relationships through plastid genome sequencing: did alveolate plastids emerge through endosymbiosis of an ochrophyte? Sci Rep 2015; 5:10134. [PMID: 26017773 PMCID: PMC4603697 DOI: 10.1038/srep10134] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/31/2015] [Indexed: 01/15/2023] Open
Abstract
Algae with secondary plastids of a red algal origin, such as ochrophytes (photosynthetic stramenopiles), are diverse and ecologically important, yet their evolutionary history remains controversial. We sequenced plastid genomes of two ochrophytes, Ochromonas sp. CCMP1393 (Chrysophyceae) and Trachydiscus minutus (Eustigmatophyceae). A shared split of the clpC gene as well as phylogenomic analyses of concatenated protein sequences demonstrated that chrysophytes and eustigmatophytes form a clade, the Limnista, exhibiting an unexpectedly elevated rate of plastid gene evolution. Our analyses also indicate that the root of the ochrophyte phylogeny falls between the recently redefined Khakista and Phaeista assemblages. Taking advantage of the expanded sampling of plastid genome sequences, we revisited the phylogenetic position of the plastid of Vitrella brassicaformis, a member of Alveolata with the least derived plastid genome known for the whole group. The results varied depending on the dataset and phylogenetic method employed, but suggested that the Vitrella plastids emerged from a deep ochrophyte lineage rather than being derived vertically from a hypothetical plastid-bearing common ancestor of alveolates and stramenopiles. Thus, we hypothesize that the plastid in Vitrella, and potentially in other alveolates, may have been acquired by an endosymbiosis of an early ochrophyte.
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Affiliation(s)
- Tereza Ševčíková
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Aleš Horák
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic.,University of South Bohemia, Faculty of Science, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Vladimír Klimeš
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Veronika Zbránková
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, Chittussiho 10, 710 00 Ostrava, Czech Republic
| | - Elif Demir-Hilton
- Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, CA 95039, USA
| | - Sebastian Sudek
- Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, CA 95039, USA
| | - Jerry Jenkins
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology, 601 Genome Way NW, Huntsville, Alabama 35806, USA
| | - Pavel Přibyl
- Centre for Algology and Biorefinery Research Centre of Competence, Institute of Botany, Czech Academy of Sciences, Dukelská 135, 379 82 Třeboň, Czech Republic
| | - Jan Fousek
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Čestmír Vlček
- Institute of Molecular Genetics, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - B Franz Lang
- Département de Biochimie, Centre Robert-Cedergren, Université de Montréal, 2900 Boulevard Edouard Montpetit, Montréal, Québec, H3C 3J7, Canada
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic.,University of South Bohemia, Faculty of Science, Branišovská 1760, 370 05 České Budějovice, Czech Republic
| | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute (MBARI), Moss Landing, CA 95039, USA.,Integrated Microbial Biodiversity Program, Canadian Institute for Advanced Research, Toronto, M5G 1Z8, Canada
| | - Marek Eliáš
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, Chittussiho 10, 710 00 Ostrava, Czech Republic
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Hunsperger HM, Randhawa T, Cattolico RA. Extensive horizontal gene transfer, duplication, and loss of chlorophyll synthesis genes in the algae. BMC Evol Biol 2015; 15:16. [PMID: 25887237 PMCID: PMC4337275 DOI: 10.1186/s12862-015-0286-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/15/2015] [Indexed: 11/10/2022] Open
Abstract
Background Two non-homologous, isofunctional enzymes catalyze the penultimate step of chlorophyll a synthesis in oxygenic photosynthetic organisms such as cyanobacteria, eukaryotic algae and land plants: the light-independent (LIPOR) and light-dependent (POR) protochlorophyllide oxidoreductases. Whereas the distribution of these enzymes in cyanobacteria and land plants is well understood, the presence, loss, duplication, and replacement of these genes have not been surveyed in the polyphyletic and remarkably diverse eukaryotic algal lineages. Results A phylogenetic reconstruction of the history of the POR enzyme (encoded by the por gene in nuclei) in eukaryotic algae reveals replacement and supplementation of ancestral por genes in several taxa with horizontally transferred por genes from other eukaryotic algae. For example, stramenopiles and haptophytes share por gene duplicates of prasinophytic origin, although their plastid ancestry predicts a rhodophytic por signal. Phylogenetically, stramenopile pors appear ancestral to those found in haptophytes, suggesting transfer from stramenopiles to haptophytes by either horizontal or endosymbiotic gene transfer. In dinoflagellates whose plastids have been replaced by those of a haptophyte or diatom, the ancestral por genes seem to have been lost whereas those of the new symbiotic partner are present. Furthermore, many chlorarachniophytes and peridinin-containing dinoflagellates possess por gene duplicates. In contrast to the retention, gain, and frequent duplication of algal por genes, the LIPOR gene complement (chloroplast-encoded chlL, chlN, and chlB genes) is often absent. LIPOR genes have been lost from haptophytes and potentially from the euglenid and chlorarachniophyte lineages. Within the chlorophytes, rhodophytes, cryptophytes, heterokonts, and chromerids, some taxa possess both POR and LIPOR genes while others lack LIPOR. The gradual process of LIPOR gene loss is evidenced in taxa possessing pseudogenes or partial LIPOR gene compliments. No horizontal transfer of LIPOR genes was detected. Conclusions We document a pattern of por gene acquisition and expansion as well as loss of LIPOR genes from many algal taxa, paralleling the presence of multiple por genes and lack of LIPOR genes in the angiosperms. These studies present an opportunity to compare the regulation and function of por gene families that have been acquired and expanded in patterns unique to each of various algal taxa. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0286-4) contains supplementary material, which is available to authorized users.
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44
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Kessenich CR, Ruck EC, Schurko AM, Wickett NJ, Alverson AJ. Transcriptomic Insights into the Life History of Bolidophytes, the Sister Lineage to Diatoms. JOURNAL OF PHYCOLOGY 2014; 50:977-983. [PMID: 26988780 DOI: 10.1111/jpy.12222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 06/17/2014] [Indexed: 06/05/2023]
Abstract
Diatoms are perhaps the most diverse lineage of eukaryotic algae, with their siliceous cell wall and diplontic life history often considered to have played important roles in their extraordinary diversification. The characteristic diminution of the diatom cell wall over the course of vegetative growth provides a reliable, intrinsic trigger for sexual reproduction, establishing a direct link between the evolution of their cell-wall and life-history features. It is unclear, however, whether the diplontic life cycle of diatoms represents an ancestral or derived trait. This uncertainty is based in part on our lack of understanding of the life cycle of the sister lineage to diatoms, which includes a mix of two free-living and separately classified forms: naked biflagellate unicells in the genus Bolidomonas and silicified forms in the order Parmales. These two forms might represent different life-history stages, although directly establishing such links can be difficult. We sequenced transcriptomes for Bolidomonas and two diatoms and found that ~0.1% of the coding regions in the two diploid diatoms are heterozygous, whereas Bolidomonas is virtually devoid of heterozygous alleles, consistent with expectations for a haploid genome. These results suggest that Bolidomonas is haploid and predict that parmaleans represent the diploid phase of a haplodiplontic life cycle. These data fill an important gap in our understanding of the origin of the diplontic life history of diatoms, which may represent an evolutionarily derived, adaptive feature.
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Affiliation(s)
- Colton R Kessenich
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, 72701, USA
| | - Elizabeth C Ruck
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, 72701, USA
| | - Andrew M Schurko
- Department of Biology, Hendrix College, Conway, Arkansas, 72032, USA
| | - Norman J Wickett
- Chicago Botanic Garden, Glencoe, Illinois, 60022, USA
- Program in Biological Sciences, Northwestern University, Evanston, Illinois, 60208, USA
| | - Andrew J Alverson
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, 72701, USA
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Kaczmarska I, Mather L, Luddington IA, Muise F, Ehrman JM. Cryptic diversity in a cosmopolitan diatom known as Asterionellopsis glacialis (Fragilariaceae): Implications for ecology, biogeography, and taxonomy. AMERICAN JOURNAL OF BOTANY 2014; 101:267-286. [PMID: 24509794 DOI: 10.3732/ajb.1300306] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
PREMISE OF THE STUDY Diatoms have long been known as the most species-rich of algal groups, with a wide range of estimates for species number (20-200 k) due to differing species concepts. The fine valve structure in Asterionellopsis glacialis, a diatom believed cosmopolitan and eurytopic, has never been systematically examined using modern microscopy and is an excellent candidate to genetically test morphology-based conspecificity among its geographically distant culture isolates. METHODS Isolates from the Atlantic and Pacific Oceans that were morphologically delineated as A. glacialis were genetically characterized using three nuclear DNA regions (two 18S rDNA fragments and ITS region) and one plastidal (rbcL) and one mitochondrial gene (cox1) and related to SEM-based morphometrics. KEY RESULTS Five genetically distinct groupings were found, four of which are new to science. ITS2 RNA transcript secondary structure was species specific as were plastidal and mitochondrial genes, while the 18S gene fragments did not diverge sufficiently to segregate new species efficiently. We genetically circumscribed the A. glacialis epitype. CONCLUSIONS The morphological diversification of the species examined in this study lags behind their genetic divergence. The currently accepted 2% cutoff level of operational taxonomic unit (OTU) clustering in 18S rDNA environmental sequencing is too high to recognize genetic diversity in Asterionellopsis and very likely in many other species. Our results support the notion that a considerable number of species and diversity remain to be discovered among diatoms and that species number may be more in line with higher estimates. Molecular signatures of the species discovered here will aid in their globally consistent identification and ultimate understanding of their ecology.
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Affiliation(s)
- Irena Kaczmarska
- Biology Department, Mount Allison University, Sackville, New Brunswick E4L 1G7 Canada
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Raven JA. Iron acquisition and allocation in stramenopile algae. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2119-27. [PMID: 23658428 DOI: 10.1093/jxb/ert121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The essential element iron has a low biological availability in the surface ocean where photosynthetic organisms live. Recent advances in our understanding of iron acquisition mechanisms in brown algae and diatoms (stramenopile algae) show the importance of the reduction of ferric to ferrous iron prior to, or during, transport in the uptake process. The uses of iron in photosynthetic stramenopiles resembles that in other oxygenic organisms, although (with the exception of the diatom Thalassiosira oceanica from an iron-deficient part of the ocean) they lack plastocyanin, instead using cytochrome c 6, This same diatom further economizes genotypically on the use of iron in photosynthesis by decreasing the expression of photosystem I, cytochrome c 6, and the cytochrome b 6 f complex per cell and per photosystem II relative to the coastal Thalassiosira pseudonana; similar changes occur phenotypically in response to iron deficiency in other diatoms such as Phaeodactylum tricornutum. In some diatoms grown under iron-limiting conditions, essentially all of the iron in the cells can be accounted for by the iron occurring in catalytic proteins. However, stramenopiles can store iron. Genomic studies show that pennate, but not centric, diatoms have the iron storage protein ferritin. While Mössbauer and X-ray analysis of (57)Fe-labelled Ectocarpus siliculosus shows iron in an amorphous mineral phase resembling the core of ferritin, the genome shows no protein with significant sequence similarity to ferritin.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK.
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Rybalka N, Wolf M, Andersen RA, Friedl T. Congruence of chloroplast- and nuclear-encoded DNA sequence variations used to assess species boundaries in the soil microalga Heterococcus (Stramenopiles, Xanthophyceae). BMC Evol Biol 2013; 13:39. [PMID: 23402662 PMCID: PMC3598724 DOI: 10.1186/1471-2148-13-39] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 02/05/2013] [Indexed: 11/15/2022] Open
Abstract
Background Heterococcus is a microalgal genus of Xanthophyceae (Stramenopiles) that is common and widespread in soils, especially from cold regions. Species are characterized by extensively branched filaments produced when grown on agarized culture medium. Despite the large number of species described exclusively using light microscopic morphology, the assessment of species diversity is hampered by extensive morphological plasticity. Results Two independent types of molecular data, the chloroplast-encoded psbA/rbcL spacer complemented by rbcL gene and the internal transcribed spacer 2 of the nuclear rDNA cistron (ITS2), congruently recovered a robust phylogenetic structure. With ITS2 considerable sequence and secondary structure divergence existed among the eight species, but a combined sequence and secondary structure phylogenetic analysis confined to helix II of ITS2 corroborated relationships as inferred from the rbcL gene phylogeny. Intra-genomic divergence of ITS2 sequences was revealed in many strains. The ‘monophyletic species concept’, appropriate for microalgae without known sexual reproduction, revealed eight different species. Species boundaries established using the molecular-based monophyletic species concept were more conservative than the traditional morphological species concept. Within a species, almost identical chloroplast marker sequences (genotypes) were repeatedly recovered from strains of different origins. At least two species had widespread geographical distributions; however, within a given species, genotypes recovered from Antarctic strains were distinct from those in temperate habitats. Furthermore, the sequence diversity may correspond to adaptation to different types of habitats or climates. Conclusions We established a method and a reference data base for the unambiguous identification of species of the common soil microalgal genus Heterococcus which uses DNA sequence variation in markers from plastid and nuclear genomes. The molecular data were more reliable and more conservative than morphological data.
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Affiliation(s)
- Nataliya Rybalka
- Experimental Phycology and Culture Collection of Algae (SAG), Georg August University Göttingen, Untere Karspüle 2a, Göttingen, 37073, Germany
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Charvet S, Vincent WF, Comeau A, Lovejoy C. Pyrosequencing analysis of the protist communities in a High Arctic meromictic lake: DNA preservation and change. Front Microbiol 2012; 3:422. [PMID: 23267353 PMCID: PMC3526917 DOI: 10.3389/fmicb.2012.00422] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 11/24/2012] [Indexed: 11/30/2022] Open
Abstract
High Arctic meromictic lakes are extreme environments characterized by cold temperatures, low nutrient inputs from their polar desert catchments and prolonged periods of low irradiance and darkness. These lakes are permanently stratified with an oxygenated freshwater layer (mixolimnion) overlying a saline, anoxic water column (monimolimnion). The physical and chemical properties of the deepest known lake of this type in the circumpolar Arctic, Lake A, on the far northern coast of Ellesmere Island, Canada, have been studied over the last 15 years, but little is known about the lake’s biological communities. We applied high-throughput sequencing of the V4 region of the 18S ribosomal RNA gene to investigate the protist communities down the water column at three sampling times: under the ice at the end of winter in 2008, during an unusual period of warming and ice-out the same year, and again under the ice in mid-summer 2009. Sequences of many protist taxa occurred throughout the water column at all sampling times, including in the deep anoxic layer where growth is highly unlikely. Furthermore, there were sequences for taxonomic groups including diatoms and marine taxa, which have never been observed in Lake A by microscopic analysis. However, the sequences of other taxa such as ciliates, chrysophytes, Cercozoa, and Telonema varied with depth, between years and during the transition to ice-free conditions. These seasonally active taxa in the surface waters of the lake are thus sensitive to depth and change with time. DNA from these taxa is superimposed upon background DNA from multiple internal and external sources that is preserved in the deep, cold, largely anoxic water column.
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Affiliation(s)
- Sophie Charvet
- Département de Biologie, Université Laval, Québec QC, Canada ; Québec-Océan, Québec QC, Canada
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Phylogeny of Heterokonta: Incisomonas marina, a uniciliate gliding opalozoan related to Solenicola (Nanomonadea), and evidence that Actinophryida evolved from raphidophytes. Eur J Protistol 2012; 49:328-53. [PMID: 23219323 DOI: 10.1016/j.ejop.2012.09.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 09/29/2012] [Accepted: 09/30/2012] [Indexed: 12/28/2022]
Abstract
Environmental rDNA sequencing has revealed many novel heterokont clades of unknown morphology. We describe a new marine heterotrophic heterokont flagellate, Incisomonas marina, which most unusually lacks an anterior cilium. It glides and swims with its cilium trailing behind, but is predominantly sedentary on the substratum, with or without a cilium. 18S rDNA sequence phylogeny groups Incisomonas strongly within clade MAST-3; with others it forms a robust sister clade to Solenicola, here grouped with it as new order Uniciliatida, placed within new class Nanomonadea encompassing MAST-3. Our comprehensive maximum likelihood heterokont phylogeny shows Nanomonadea as sister to MAST-12 plus Opalinata within Opalozoa, and that Actinophryida are not Opalozoa (previously suggested by distance trees), but highly modified raphidomonads, arguably related to Heliorapha (formerly Ciliophrys) azurina gen., comb. n. We discuss evolution of Actinophryida from photosynthetic raphidophytes. Clades MAST-4,6-11 form one early-branching bigyran clade. Olisthodiscus weakly groups with Hypogyristea not Raphidomonadea. Phylogenetic analysis shows that MAST-13 is all Bicosoeca. Some gliding uniciliates similar to Incisomonas marina seem to have been misclassified: therefore we establish Incisomonas devorata comb. n. for Rigidomastix devoratum, revise the genus Rigidomastix, transfer Clautriavia parva to Kiitoksia. We make 17 new familes (13 heterokont (three algal), two cercozoan, two amoebozoan).
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Schmidt M, Horn S, Flieger K, Ehlers K, Wilhelm C, Schnetter R. Synchroma pusillum sp. nov. and other new algal isolates with chloroplast complexes confirm the Synchromophyceae (Ochrophyta) as a widely distributed group of amoeboid algae. Protist 2012; 163:544-59. [PMID: 22578425 DOI: 10.1016/j.protis.2011.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 11/28/2011] [Accepted: 11/21/2011] [Indexed: 10/28/2022]
Abstract
Seven new isolates of the heterokont algal class Synchromophyceae are described from coastal habitats of the Atlantic Ocean, including the Caribbean and Mediterranean Seas. All of the new isolates contain chloroplast complexes, a key feature of this group of algae. Morphology, pigments and DNA sequences support a monophyletic grouping of the Synchromophyceae to the exclusion of other Ochrophyta (primarily photosynthetic stramenopiles). Within the Synchromophyceae, two phylogenetic clades based on rbcL and 18S rDNA data were discovered, which differ in cell size and also the number of plastid complexes per cell. Two isolates form a clade with the type species Synchroma grande, while all other isolates form a separate clade, including the newly described species S. pusillum. Further species delineation of the isolates is difficult due to the highly similar morphology and life cycle strategy. Phylogenetic relationships with other genera of the Ochrophyta, such as Leukarachnion and Chlamydomyxa, are apparent and shed light on a heterogeneous branch of heterokont evolution.
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Affiliation(s)
- Maria Schmidt
- Institut für Biologie, Abteilung Pflanzenphysiologie, Universität Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany
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