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Cho A, Tikhonenkov DV, Lax G, Prokina KI, Keeling PJ. Phylogenomic position of genetically diverse phagotrophic stramenopile flagellates in the sediment-associated MAST-6 lineage and a potentially halotolerant placididean. Mol Phylogenet Evol 2024; 190:107964. [PMID: 37951557 DOI: 10.1016/j.ympev.2023.107964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 11/14/2023]
Abstract
Unlike morphologically conspicuous ochrophytes, many flagellates belonging to basally branching stramenopiles are small and often overlooked. As a result, many of these lineages are known only through molecular surveys and identified as MArine STramenopiles (MAST), and remain largely uncharacterized at the cellular or genomic level. These likely phagotrophic flagellates are not only phylogenetically diverse, but also extremely abundant in some environments, making their characterization all the more important. MAST-6 is one example of a phylogenetically distinct group that has been known to be associated with sediments, but little else is known about it. Indeed, until the present study, only a single species from this group, Pseudophyllomitus vesiculosus (Pseudophyllomitidae), has been both formally described and associated with genomic information. Here, we describe four new species including two new genera of sediment-dwelling MAST-6, Vomastramonas tehuelche gen. et sp. nov., Mastreximonas tlaamin gen. et sp. nov., one undescribed Pseudophyllomitus sp., BSC2, and a new species belonging to Placididea, the potentially halotolerant Haloplacidia sinai sp. nov. We also provide two additional bikosian transcriptomes from a public culture collection, to allow for better phylogenetic reconstructions of deep-branching stramenopiles. With the SSU rRNA sequences of the new MAST-6 species, we investigate the phylogenetic diversity of the MAST-6 group and show a high relative abundance of MAST-6 related to M. tlaamin in samples across various depths and geographical locations. Using the new MAST-6 species, we also update the phylogenomic tree of stramenopiles, particularly focusing on the paraphyly of Bigyra.
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Affiliation(s)
- Anna Cho
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada.
| | - Denis V Tikhonenkov
- Papanin Institute for Biology of Inland Waters, Russian Academy of Science, Borok 152742, Russia
| | - Gordon Lax
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
| | - Kristina I Prokina
- Papanin Institute for Biology of Inland Waters, Russian Academy of Science, Borok 152742, Russia; Ecologie Systématique Evolution, CNRS, Université Paris-Saclay, AgroParisTech, Gif-sur-Yvette, France
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada
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Weston EJ, Eglit Y, Simpson AGB. Kaonashia insperata gen. et sp. nov., a eukaryotrophic flagellate, represents a novel major lineage of heterotrophic stramenopiles. J Eukaryot Microbiol 2024; 71:e13003. [PMID: 37803921 DOI: 10.1111/jeu.13003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023]
Abstract
Eukaryotrophic protists are ecologically significant and possess characteristics key to understanding the evolution of eukaryotes; however, they remain poorly studied, due partly to the complexities of maintaining predator-prey cultures. Kaonashia insperata, gen. nov., et sp. nov., is a free-swimming biflagellated eukaryotroph with a conspicuous ventral groove, a trait observed in distantly related lineages across eukaryote diversity. Di-eukaryotic (predator-prey) cultures of K. insperata with three marine algae (Isochrysis galbana, Guillardia theta, and Phaeodactylum tricornutum) were established by single-cell isolation. Growth trials showed that the studied K. insperata clone grew particularly well on G. theta, reaching a peak abundance of 1.0 × 105 ± 4.0 × 104 cells ml-1 . Small-subunit ribosomal DNA phylogenies infer that K. insperata is a stramenopile with moderate support; however, it does not fall within any well-defined phylogenetic group, including environmental sequence clades (e.g. MASTs), and its specific placement remains unresolved. Electron microscopy shows traits consistent with stramenopile affinity, including mastigonemes on the anterior flagellum and tubular mitochondrial cristae. Kaonashia insperata may represent a novel major lineage within stramenopiles, and be important for understanding the evolutionary history of the group. While heterotrophic stramenopile flagellates are considered to be predominantly bacterivorous, eukaryotrophy may be relatively widespread amongst this assemblage.
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Affiliation(s)
- Elizabeth J Weston
- Institute for Comparative Genomics, and Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Yana Eglit
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Alastair G B Simpson
- Institute for Comparative Genomics, and Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
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Cavalier-Smith T. Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi. PROTOPLASMA 2022; 259:487-593. [PMID: 34940909 PMCID: PMC9010356 DOI: 10.1007/s00709-021-01665-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/03/2021] [Indexed: 05/19/2023]
Abstract
I thoroughly discuss ciliary transition zone (TZ) evolution, highlighting many overlooked evolutionarily significant ultrastructural details. I establish fundamental principles of TZ ultrastructure and evolution throughout eukaryotes, inferring unrecognised ancestral TZ patterns for Fungi, opisthokonts, and Corticata (i.e., kingdoms Plantae and Chromista). Typical TZs have a dense transitional plate (TP), with a previously overlooked complex lattice as skeleton. I show most eukaryotes have centriole/TZ junction acorn-V filaments (whose ancestral function was arguably supporting central pair microtubule-nucleating sites; I discuss their role in centriole growth). Uniquely simple malawimonad TZs (without TP, simpler acorn) pinpoint the eukaryote tree's root between them and TP-bearers, highlighting novel superclades. I integrate TZ/ciliary evolution with the best multiprotein trees, naming newly recognised major eukaryote clades and revise megaclassification of basal kingdom Protozoa. Recent discovery of non-photosynthetic phagotrophic flagellates with genome-free plastids (Rhodelphis), the sister group to phylum Rhodophyta (red algae), illuminates plant and chromist early evolution. I show previously overlooked marked similarities in cell ultrastructure between Rhodelphis and Picomonas, formerly considered an early diverging chromist. In both a nonagonal tube lies between their TP and an annular septum surrounding their 9+2 ciliary axoneme. Mitochondrial dense condensations and mitochondrion-linked smooth endomembrane cytoplasmic partitioning cisternae further support grouping Picomonadea and Rhodelphea as new plant phylum Pararhoda. As Pararhoda/Rhodophyta form a robust clade on site-heterogeneous multiprotein trees, I group Pararhoda and Rhodophyta as new infrakingdom Rhodaria of Plantae within subkingdom Biliphyta, which also includes Glaucophyta with fundamentally similar TZ, uniquely in eukaryotes. I explain how biliphyte TZs generated viridiplant stellate-structures.
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Cho A, Tikhonenkov DV, Hehenberger E, Karnkowska A, Mylnikov AP, Keeling PJ. Monophyly of Diverse Bigyromonadea and their Impact on Phylogenomic Relationships Within Stramenopiles. Mol Phylogenet Evol 2022; 171:107468. [DOI: 10.1016/j.ympev.2022.107468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 02/11/2022] [Accepted: 02/22/2022] [Indexed: 10/18/2022]
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Yubuki N, Galindo LJ, Reboul G, López-García P, Brown MW, Pollet N, Moreira D. Ancient Adaptive Lateral Gene Transfers in the Symbiotic Opalina–Blastocystis Stramenopile Lineage. Mol Biol Evol 2019; 37:651-659. [DOI: 10.1093/molbev/msz250] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AbstractLateral gene transfer is a very common process in bacterial and archaeal evolution, playing an important role in the adaptation to new environments. In eukaryotes, its role and frequency remain highly debated, although recent research supports that gene transfer from bacteria to diverse eukaryotes may be much more common than previously appreciated. However, most of this research focused on animals and the true phylogenetic and functional impact of bacterial genes in less-studied microbial eukaryotic groups remains largely unknown. Here, we have analyzed transcriptome data from the deep-branching stramenopile Opalinidae, common members of frog gut microbiomes, and distantly related to the well-known genus Blastocystis. Phylogenetic analyses suggest the early acquisition of several bacterial genes in a common ancestor of both lineages. Those lateral gene transfers most likely facilitated the adaptation of the free-living ancestor of the Opalinidae–Blastocystis symbiotic group to new niches in the oxygen-depleted animal gut environment.
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Affiliation(s)
- Naoji Yubuki
- Unité d’Ecologie Systématique et Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Luis Javier Galindo
- Unité d’Ecologie Systématique et Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Guillaume Reboul
- Unité d’Ecologie Systématique et Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Purificación López-García
- Unité d’Ecologie Systématique et Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
| | - Matthew W Brown
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS
| | - Nicolas Pollet
- Laboratoire Evolution Génomes Comportement et Ecologie, CNRS, IRD, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - David Moreira
- Unité d’Ecologie Systématique et Evolution, CNRS, Université Paris-Sud, AgroParisTech, Université Paris-Saclay, Orsay, France
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Taxon-rich Multigene Phylogenetic Analyses Resolve the Phylogenetic Relationship Among Deep-branching Stramenopiles. Protist 2019; 170:125682. [DOI: 10.1016/j.protis.2019.125682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 01/09/2023]
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Grattepanche J, Walker LM, Ott BM, Paim Pinto DL, Delwiche CF, Lane CE, Katz LA. Microbial Diversity in the Eukaryotic SAR Clade: Illuminating the Darkness Between Morphology and Molecular Data. Bioessays 2018; 40:e1700198. [DOI: 10.1002/bies.201700198] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Indexed: 01/09/2023]
Affiliation(s)
| | - Laura M. Walker
- Department of Biological Sciences, Smith CollegeNorthamptonMA 01063USA
| | - Brittany M. Ott
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkMD 20742USA
| | | | - Charles F. Delwiche
- Department of Cell Biology and Molecular Genetics, University of MarylandCollege ParkMD 20742USA
| | - Christopher E. Lane
- Department of Biological SciencesUniversity of Rhode IslandKingstonRI 02881USA
| | - Laura A. Katz
- Department of Biological Sciences, Smith CollegeNorthamptonMA 01063USA
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Cavalier-Smith T. Kingdom Chromista and its eight phyla: a new synthesis emphasising periplastid protein targeting, cytoskeletal and periplastid evolution, and ancient divergences. PROTOPLASMA 2018; 255:297-357. [PMID: 28875267 PMCID: PMC5756292 DOI: 10.1007/s00709-017-1147-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/18/2017] [Indexed: 05/18/2023]
Abstract
In 1981 I established kingdom Chromista, distinguished from Plantae because of its more complex chloroplast-associated membrane topology and rigid tubular multipartite ciliary hairs. Plantae originated by converting a cyanobacterium to chloroplasts with Toc/Tic translocons; most evolved cell walls early, thereby losing phagotrophy. Chromists originated by enslaving a phagocytosed red alga, surrounding plastids by two extra membranes, placing them within the endomembrane system, necessitating novel protein import machineries. Early chromists retained phagotrophy, remaining naked and repeatedly reverted to heterotrophy by losing chloroplasts. Therefore, Chromista include secondary phagoheterotrophs (notably ciliates, many dinoflagellates, Opalozoa, Rhizaria, heliozoans) or walled osmotrophs (Pseudofungi, Labyrinthulea), formerly considered protozoa or fungi respectively, plus endoparasites (e.g. Sporozoa) and all chromophyte algae (other dinoflagellates, chromeroids, ochrophytes, haptophytes, cryptophytes). I discuss their origin, evolutionary diversification, and reasons for making chromists one kingdom despite highly divergent cytoskeletons and trophic modes, including improved explanations for periplastid/chloroplast protein targeting, derlin evolution, and ciliary/cytoskeletal diversification. I conjecture that transit-peptide-receptor-mediated 'endocytosis' from periplastid membranes generates periplastid vesicles that fuse with the arguably derlin-translocon-containing periplastid reticulum (putative red algal trans-Golgi network homologue; present in all chromophytes except dinoflagellates). I explain chromist origin from ancestral corticates and neokaryotes, reappraising tertiary symbiogenesis; a chromist cytoskeletal synapomorphy, a bypassing microtubule band dextral to both centrioles, favoured multiple axopodial origins. I revise chromist higher classification by transferring rhizarian subphylum Endomyxa from Cercozoa to Retaria; establishing retarian subphylum Ectoreta for Foraminifera plus Radiozoa, apicomonad subclasses, new dinozoan classes Myzodinea (grouping Colpovora gen. n., Psammosa), Endodinea, Sulcodinea, and subclass Karlodinia; and ranking heterokont Gyrista as phylum not superphylum.
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Shiratori T, Thakur R, Ishida KI. Pseudophyllomitus vesiculosus (Larsen and Patterson 1990) Lee, 2002, a Poorly Studied Phagotrophic Biflagellate is the First Characterized Member of Stramenopile Environmental Clade MAST-6. Protist 2017; 168:439-451. [PMID: 28822908 DOI: 10.1016/j.protis.2017.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 01/17/2023]
Abstract
There are many eukaryotic lineages that are exclusively composed of environmental sequences and lack information about which species are included. Regarding stramenopiles, at least 18 environmental lineages, known as marine stramenopiles (MAST), have been recognized. Since each MAST lineage forms deep branches in the stramenopiles, the characterization of MAST members is key to understanding the diversity and evolution of stramenopiles. In this study, we established a culture of Pseudophyllomitus vesiculosus, which is a poorly studied phagotrophic flagellate of uncertain taxonomic position. Our molecular phylogenetic analyses based on small subunit ribosomal RNA gene sequences robustly supported the inclusion of P. vesiculosus in the MAST-6 clade. Our microscopic observations indicated that P. vesiculosus shared characteristics with stramenopiles, including an anterior flagellum that exhibits sinusoidal waves and bears tubular mastigonemes. The flagellar apparatus of P. vesiculosus was also similar to that of other stramenopiles in having a transitional helix and five microtubular roots (R1-R4 and S tubules) including R2 that split into two bands. On the other hand, P. vesiculosus was distinguished from other deep-branching stramenopiles by the combination of flagellar apparatus characteristics. Based on the phylogenetic analyses and microscopic observations, we established Pseudophyllomitidae fam. nov in stramenopiles.
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Affiliation(s)
- Takashi Shiratori
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan.
| | - Rabindra Thakur
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Ken-Ichiro Ishida
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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Evolution of the microtubular cytoskeleton (flagellar apparatus) in parasitic protists. Mol Biochem Parasitol 2016; 209:26-34. [DOI: 10.1016/j.molbiopara.2016.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 02/02/2016] [Accepted: 02/05/2016] [Indexed: 01/16/2023]
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