51
|
Heiss AA, Warring SD, Lukacs K, Favate J, Yang A, Gyaltshen Y, Filardi C, Simpson AGB, Kim E. Description of Imasa heleensis, gen. nov., sp. nov. (Imasidae, fam. nov.), a Deep-Branching Marine Malawimonad and Possible Key Taxon in Understanding Early Eukaryotic Evolution. J Eukaryot Microbiol 2020; 68:e12837. [PMID: 33274482 DOI: 10.1111/jeu.12837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/23/2020] [Accepted: 11/13/2020] [Indexed: 12/23/2022]
Abstract
Malawimonadida is a deep-level (arguably "kingdom-scale") lineage of eukaryotes whose phylogenetic affinities are uncertain but of great evolutionary interest, as the group is suspected to branch close to the root of the tree of eukaryotes. Part of the difficulty in placing Malawimonadida phylogenetically is its tiny circumscription: at present, it comprises only two described and one cultured but undescribed species, all of them are freshwater suspension-feeding nanoflagellates. In this study, we cultivated and characterised Imasa heleensis gen. nov., sp. nov. (Imasidae fam. nov.), the first marine malawimonad to be described. Light and electron microscopy observations show that Imasa is largely similar to other malawimonads, but more frequently adheres to the substrate, often by means of a pliable posterior extension. Phylogenetic analyses based on two ribosomal RNA genes and four translated protein-coding genes using three different taxon sets place Imasa as sister to the three freshwater malawimonad strains with strong support. Imasa's mitochondrial genome is circular-mapping and shows a similar gene complement to other known malawimonads. We conclude that Imasa represents an important expansion of the range of taxa available for future evolutionary study.
Collapse
Affiliation(s)
- Aaron A Heiss
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | - Sally D Warring
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | - Kaleigh Lukacs
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | - John Favate
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | - Ashley Yang
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | - Yangtsho Gyaltshen
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| | | | - Alastair G B Simpson
- Department of Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, 1355 Oxford St, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Eunsoo Kim
- Department of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, Central Park West at 79th Street, New York City, New York, 10024, USA
| |
Collapse
|
52
|
Horizontal Gene Transfer in Eukaryotes: Not if, but How Much? Trends Genet 2020; 36:915-925. [DOI: 10.1016/j.tig.2020.08.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 12/17/2022]
|
53
|
Heterotrophic flagellates and centrohelid heliozoans from marine waters of Curacao, the Netherlands Antilles. Eur J Protistol 2020; 77:125758. [PMID: 33307359 DOI: 10.1016/j.ejop.2020.125758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/22/2020] [Accepted: 11/11/2020] [Indexed: 11/23/2022]
Abstract
Recent progress in understanding the early evolution of eukaryotes was tied to morphological identification of flagellates and heliozoans from natural samples, isolation of their culture and genomic and ultrastructural investigations. These protists are the smallest and least studied microbial eukaryotes but play an important role in the functioning of microbial food webs. Using light and electron microscopy, we have studied the diversity of heterotrophic flagellates and centrohelid heliozoans from marine waters of Curacao (The Netherlands Antilles), and provide micrographs and morphological descriptions of observed species. Among 86 flagellates and 3 centrohelids encountered in this survey, five heterotrophic flagellates and one сentrohelid heliozoan were not identified even to the genus. Some flagellate protists have a unique morphology, and may represent undescribed lineages of eukaryotes of high taxonomic rank. The vast majority (89%) of identified flagellates is characterized by wide geographical distribution and have been reported previously from all hemispheres and various climatic regions. More than half of the species were previously observed not only from marine, but also from freshwater habitats. The parameters of the species accumulation curve indicate that our species list obtained for the Curacao study sites is far from complete, and each new sample should yield new species.
Collapse
|
54
|
Hanschen ER, Hovde BT, Starkenburg SR. An evaluation of methodology to determine algal genome completeness. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
55
|
Kayama M, Chen JF, Nakada T, Nishimura Y, Shikanai T, Azuma T, Miyashita H, Takaichi S, Kashiyama Y, Kamikawa R. A non-photosynthetic green alga illuminates the reductive evolution of plastid electron transport systems. BMC Biol 2020; 18:126. [PMID: 32938439 PMCID: PMC7495860 DOI: 10.1186/s12915-020-00853-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/21/2020] [Indexed: 11/12/2022] Open
Abstract
Background Plastid electron transport systems are essential not only for photosynthesis but also for dissipating excess reducing power and sinking excess electrons generated by various redox reactions. Although numerous organisms with plastids have lost their photoautotrophic lifestyles, there is a spectrum of known functions of remnant plastids in non-photosynthetic algal/plant lineages; some of non-photosynthetic plastids still retain diverse metabolic pathways involving redox reactions while others, such as apicoplasts of apicomplexan parasites, possess highly reduced sets of functions. However, little is known about underlying mechanisms for redox homeostasis in functionally versatile non-photosynthetic plastids and thus about the reductive evolution of plastid electron transport systems. Results Here we demonstrated that the central component for plastid electron transport systems, plastoquinone/plastoquinol pool, is still retained in a novel strain of an obligate heterotrophic green alga lacking the photosynthesis-related thylakoid membrane complexes. Microscopic and genome analyses revealed that the Volvocales green alga, chlamydomonad sp. strain NrCl902, has non-photosynthetic plastids and a plastid DNA that carries no genes for the photosynthetic electron transport system. Transcriptome-based in silico prediction of the metabolic map followed by liquid chromatography analyses demonstrated carotenoid and plastoquinol synthesis, but no trace of chlorophyll pigments in the non-photosynthetic green alga. Transient RNA interference knockdown leads to suppression of plastoquinone/plastoquinol synthesis. The alga appears to possess genes for an electron sink system mediated by plastid terminal oxidase, plastoquinone/plastoquinol, and type II NADH dehydrogenase. Other non-photosynthetic algae/land plants also possess key genes for this system, suggesting a broad distribution of an electron sink system in non-photosynthetic plastids. Conclusion The plastoquinone/plastoquinol pool and thus the involved electron transport systems reported herein might be retained for redox homeostasis and might represent an intermediate step towards a more reduced set of the electron transport system in many non-photosynthetic plastids. Our findings illuminate a broadly distributed but previously hidden step of reductive evolution of plastid electron transport systems after the loss of photosynthesis.
Collapse
Affiliation(s)
- Motoki Kayama
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu cho, Sakyo ku, Kyoto, Kyoto, 606-8501, Japan
| | - Jun-Feng Chen
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu cho, Sakyo ku, Kyoto, Kyoto, 606-8501, Japan
| | - Takashi Nakada
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | | | | | - Tomonori Azuma
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu cho, Sakyo ku, Kyoto, Kyoto, 606-8501, Japan
| | - Hideaki Miyashita
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu cho, Sakyo ku, Kyoto, Kyoto, 606-8501, Japan
| | - Shinichi Takaichi
- Department of Molecular Microbiology, Tokyo University of Agriculture, Tokyo, Japan
| | - Yuichiro Kashiyama
- Graduate School of Engineering, Fukui University of Technology, Fukui, Japan
| | - Ryoma Kamikawa
- Graduate School of Human and Environmental Studies, Kyoto University, Yoshida nihonmatsu cho, Sakyo ku, Kyoto, Kyoto, 606-8501, Japan. .,Graduate School of Agriculture, Kyoto University, Kitashirakawa oiwake cho, Sakyo ku, Kyoto, Kyoto, 606-8502, Japan.
| |
Collapse
|
56
|
Yazaki E, Kume K, Shiratori T, Eglit Y, Tanifuji G, Harada R, Simpson AGB, Ishida KI, Hashimoto T, Inagaki Y. Barthelonids represent a deep-branching metamonad clade with mitochondrion-related organelles predicted to generate no ATP. Proc Biol Sci 2020; 287:20201538. [PMID: 32873198 PMCID: PMC7542792 DOI: 10.1098/rspb.2020.1538] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We here report the phylogenetic position of barthelonids, small anaerobic flagellates previously examined using light microscopy alone. Barthelona spp. were isolated from geographically distinct regions and we established five laboratory strains. Transcriptomic data generated from one Barthelona strain (PAP020) were used for large-scale, multi-gene phylogenetic (phylogenomic) analyses. Our analyses robustly placed strain PAP020 at the base of the Fornicata clade, indicating that barthelonids represent a deep-branching metamonad clade. Considering the anaerobic/microaerophilic nature of barthelonids and preliminary electron microscopy observations on strain PAP020, we suspected that barthelonids possess functionally and structurally reduced mitochondria (i.e. mitochondrion-related organelles or MROs). The metabolic pathways localized in the MRO of strain PAP020 were predicted based on its transcriptomic data and compared with those in the MROs of fornicates. We here propose that strain PAP020 is incapable of generating ATP in the MRO, as no mitochondrial/MRO enzymes involved in substrate-level phosphorylation were detected. Instead, we detected a putative cytosolic ATP-generating enzyme (acetyl-CoA synthetase), suggesting that strain PAP020 depends on ATP generated in the cytosol. We propose two separate losses of substrate-level phosphorylation from the MRO in the clade containing barthelonids and (other) fornicates.
Collapse
Affiliation(s)
- Euki Yazaki
- Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN, Wako, Saitama, Japan
| | - Keitaro Kume
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takashi Shiratori
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yana Eglit
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Goro Tanifuji
- Department of Zoology, National Museum of Nature and Science, Ibaraki, Japan
| | - Ryo Harada
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Alastair G B Simpson
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.,Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ken-Ichiro Ishida
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tetsuo Hashimoto
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yuji Inagaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.,Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| |
Collapse
|
57
|
|
58
|
Abstract
Developing a detailed understanding of how all known forms of life are related to one another in the tree of life has been a major preoccupation of biology since the idea of tree-like evolution first took hold. Since most life is microbial, our intuitive use of morphological comparisons to infer relatedness only goes so far, and molecular sequence data, most recently from genomes and transcriptomes, has been the primary means to infer these relationships. For prokaryotes this presented new challenges, since the degree of horizontal gene transfer led some to question the tree-like depiction of evolution altogether. Most eukaryotes are also microbial, but in contrast to prokaryotic life, the application of large-scale molecular data to the tree of eukaryotes has largely been a constructive process, leading to a small number of very diverse lineages, or 'supergroups'. The tree is not completely resolved, and contentious problems remain, but many well-established supergroups now encompass much more diversity than the traditional kingdoms. Some of the most exciting recent developments come from the discovery of branches in the tree that we previously had no inkling even existed, many of which are of great ecological or evolutionary interest. These new branches highlight the need for more exploration, by high-throughput molecular surveys, but also more traditional means of observations and cultivation.
Collapse
Affiliation(s)
- Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver V6T 1Z4, British Columbia, Canada.
| | - Fabien Burki
- Department of Organismal Biology, Program in Systematic Biology, Uppsala University, Uppsala, Sweden; Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| |
Collapse
|
59
|
Gabr A, Grossman AR, Bhattacharya D. Paulinella, a model for understanding plastid primary endosymbiosis. JOURNAL OF PHYCOLOGY 2020; 56:837-843. [PMID: 32289879 PMCID: PMC7734844 DOI: 10.1111/jpy.13003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/25/2020] [Indexed: 05/07/2023]
Abstract
The uptake and conversion of a free-living cyanobacterium into a photosynthetic organelle by the single-celled Archaeplastida ancestor helped transform the biosphere from low to high oxygen. There are two documented, independent cases of plastid primary endosymbiosis. The first is the well-studied instance in Archaeplastida that occurred ca. 1.6 billion years ago, whereas the second occurred 90-140 million years ago, establishing a permanent photosynthetic compartment (the chromatophore) in amoebae in the genus Paulinella. Here, we briefly summarize knowledge about plastid origin in the Archaeplastida and then focus on Paulinella. In particular, we describe features of the Paulinella chromatophore that make it a model for examining earlier events in the evolution of photosynthetic organelles. Our review stresses recently gained insights into the evolution of chromatophore and nuclear encoded DNA sequences in Paulinella, metabolic connectivity between the endosymbiont and cytoplasm, and systems that target proteins into the chromatophore. We also describe future work with Paulinella, and the potential rewards and challenges associated with developing further this model system.
Collapse
Affiliation(s)
- Arwa Gabr
- School of Graduate Studies, Graduate Program in Molecular Bioscience and Program in Microbiology and Molecular Genetics, Rutgers University, New Brunswick, New Jersey 08901, USA
| | - Arthur R. Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, California 94305, USA
| | | |
Collapse
|
60
|
Farré EM. The brown clock: circadian rhythms in stramenopiles. PHYSIOLOGIA PLANTARUM 2020; 169:430-441. [PMID: 32274814 DOI: 10.1111/ppl.13104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
Circadian clocks allow organisms to anticipate environmental changes associated with the diurnal light/dark cycle. Circadian oscillators have been described in plants and green algae, cyanobacteria, animals and fungi, however, little is known about the circadian clocks of photosynthetic eukaryotes outside the green lineage. Stramenopiles are a diverse group of secondary endosymbionts whose plastid originated from a red alga. Photosynthetic stramenopiles, which include diatoms and brown algae, play key roles in biogeochemical cycles and are important components of marine ecosystems. Genome annotation efforts indicated the presence of a novel type of oscillator in these organisms and the first circadian clock component in a stramenopile has been recently discovered. This review summarizes the phenotypic characterization of circadian rhythms in stramenopiles and current efforts to determine the mechanisms of this 'brown clock'. The elucidation of this brown clock will enable a deeper understanding of the role of self-sustained oscillations in the adaptation to life in marine environments.
Collapse
Affiliation(s)
- Eva M Farré
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
| |
Collapse
|
61
|
Abstract
A lineage of predatory, non-photosynthetic protists related to red algae has been discovered, changing the way we think about the biology of the first photosynthetic eukaryotes.
Collapse
Affiliation(s)
- Morgan J Colp
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - John M Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada.
| |
Collapse
|
62
|
Predatory colponemids are the sister group to all other alveolates. Mol Phylogenet Evol 2020; 149:106839. [PMID: 32325195 DOI: 10.1016/j.ympev.2020.106839] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/03/2020] [Accepted: 04/09/2020] [Indexed: 11/20/2022]
Abstract
Alveolates are a major supergroup of eukaryotes encompassing more than ten thousand free-living and parasitic species, including medically, ecologically, and economically important apicomplexans, dinoflagellates, and ciliates. These three groups are among the most widespread eukaryotes on Earth, and their environmental success can be linked to unique innovations that emerged early in each group. Understanding the emergence of these well-studied and diverse groups and their innovations has relied heavily on the discovery and characterization of early-branching relatives, which allow ancestral states to be inferred with much greater confidence. Here we report the phylogenomic analyses of 313 eukaryote protein-coding genes from transcriptomes of three members of one such group, the colponemids (Colponemidia), which support their monophyly and position as the sister lineage to all other known alveolates. Colponemid-related sequences from environmental surveys and our microscopical observations show that colponemids are not common in nature, but they are diverse and widespread in freshwater habitats around the world. Studied colponemids possess two types of extrusive organelles (trichocysts or toxicysts) for active hunting of other unicellular eukaryotes and potentially play an important role in microbial food webs. Colponemids have generally plesiomorphic morphology and illustrate the ancestral state of Alveolata. We further discuss their importance in understanding the evolution of alveolates and the origin of myzocytosis and plastids.
Collapse
|
63
|
Rockwell NC, Lagarias JC. Phytochrome evolution in 3D: deletion, duplication, and diversification. THE NEW PHYTOLOGIST 2020; 225:2283-2300. [PMID: 31595505 PMCID: PMC7028483 DOI: 10.1111/nph.16240] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/17/2019] [Indexed: 05/09/2023]
Abstract
Canonical plant phytochromes are master regulators of photomorphogenesis and the shade avoidance response. They are also part of a widespread superfamily of photoreceptors with diverse spectral and biochemical properties. Plant phytochromes belong to a clade including other phytochromes from glaucophyte, prasinophyte, and streptophyte algae (all members of the Archaeplastida) and those from cryptophyte algae. This is consistent with recent analyses supporting the existence of an AC (Archaeplastida + Cryptista) clade. AC phytochromes have been proposed to arise from ancestral cyanobacterial genes via endosymbiotic gene transfer (EGT), but most recent studies instead support multiple horizontal gene transfer (HGT) events to generate extant eukaryotic phytochromes. In principle, this scenario would be compared to the emerging understanding of early events in eukaryotic evolution to generate a coherent picture. Unfortunately, there is currently a major discrepancy between the evolution of phytochromes and the evolution of eukaryotes; phytochrome evolution is thus not a solved problem. We therefore examine phytochrome evolution in a broader context. Within this context, we can identify three important themes in phytochrome evolution: deletion, duplication, and diversification. These themes drive phytochrome evolution as organisms evolve in response to environmental challenges.
Collapse
|
64
|
Garcia‐Pichel F, Zehr JP, Bhattacharya D, Pakrasi HB. What's in a name? The case of cyanobacteria. JOURNAL OF PHYCOLOGY 2020; 56:1-5. [PMID: 31618454 PMCID: PMC7065140 DOI: 10.1111/jpy.12934] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 10/04/2019] [Indexed: 05/05/2023]
Abstract
A redefinition of the cyanobacterial lineage has been proposed based on phylogenomic analysis of distantly related nonphototrophic lineages. We define Cyanobacteria here as "Organisms in the domain bacteria able to carry out oxygenic photosynthesis with water as an electron donor and to reduce carbon dioxide as a source of carbon, or those secondarily evolved from such organisms."
Collapse
Affiliation(s)
- Ferran Garcia‐Pichel
- Center for Fundamental and Applied Microbiomics & School of Life SciencesArizona State UniversityTempeArizona85287USA
| | - Jonathan P. Zehr
- Department of Ocean SciencesUniversity of CaliforniaSanta CruzCalifornia95064USA
| | - Debashish Bhattacharya
- Department of Biochemistry and MicrobiologyRutgers UniversityNew BrunswickNew Jersey08901USA
| | | |
Collapse
|
65
|
Bhattacharya D, Price DC. The Algal Tree of Life from a Genomics Perspective. PHOTOSYNTHESIS IN ALGAE: BIOCHEMICAL AND PHYSIOLOGICAL MECHANISMS 2020. [DOI: 10.1007/978-3-030-33397-3_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
66
|
Bell D, Lin Q, Gerelle WK, Joya S, Chang Y, Taylor ZN, Rothfels CJ, Larsson A, Villarreal JC, Li FW, Pokorny L, Szövényi P, Crandall-Stotler B, DeGironimo L, Floyd SK, Beerling DJ, Deyholos MK, von Konrat M, Ellis S, Shaw AJ, Chen T, Wong GKS, Stevenson DW, Palmer JD, Graham SW. Organellomic data sets confirm a cryptic consensus on (unrooted) land-plant relationships and provide new insights into bryophyte molecular evolution. AMERICAN JOURNAL OF BOTANY 2020; 107:91-115. [PMID: 31814117 DOI: 10.1002/ajb2.1397] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Phylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably. We performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene sets, and investigated bryophyte plastome evolution. METHODS We employed diverse likelihood-based analyses to infer large-scale bryophyte phylogeny for mitochondrial and plastid data sets. We tested for changes in purifying selection in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements. RESULTS Overall land-plant relationships conflict across analyses, generally weakly. However, an underlying (unrooted) four-taxon tree is consistent across most analyses and published studies. Despite gene coverage patchiness, relationships within mosses, liverworts, and hornworts are largely congruent with previous studies, with plastid results generally better supported. Exclusion of RNA edit sites restores cases of unexpected non-monophyly to monophyly for Takakia and two hornwort genera. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophic Aneura but not Buxbaumia. Plastid genome structure is nearly invariant across bryophytes, but the tufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. CONCLUSIONS A common unrooted tree underlies embryophyte phylogeny, [(liverworts, mosses), (hornworts, vascular plants)]; rooting inconsistency across studies likely reflects substantial distance to algal outgroups. Analyses combining genomic and transcriptomic data may be misled locally for heavily RNA-edited taxa. The Buxbaumia plastome lacks hallmarks of relaxed selection found in mycoheterotrophic Aneura. Autotrophic bryophyte plastomes, including Buxbaumia, hardly vary in overall structure.
Collapse
Affiliation(s)
- David Bell
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
- UBC Botanical Garden and Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, British Columbia, V6T 1Z4, Canada
- Royal Botanic Garden, 20A Inverleith Row, Edinburgh, EH3 5LR, UK
| | - Qianshi Lin
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
- UBC Botanical Garden and Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Wesley K Gerelle
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
- UBC Botanical Garden and Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Steve Joya
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Ying Chang
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, 97331, USA
| | - Z Nathan Taylor
- Department of Biology, Indiana University, Bloomington, Indiana, 47405, USA
| | - Carl J Rothfels
- University Herbarium and Department of Integrative Biology, University of California Berkeley, Berkeley, California, 94702, USA
| | - Anders Larsson
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Juan Carlos Villarreal
- Department of Biology, Université Laval, Québec, G1V 0A6, Canada
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Fay-Wei Li
- Boyce Thompson Institute, Ithaca, New York, 14853, USA
- Plant Biology Section, Cornell University, Ithaca, New York, 14853, USA
| | - Lisa Pokorny
- Royal Botanic Gardens, Kew, Richmond, TW9 3DS, Surrey, UK
- Centre for Plant Biotechnology and Genomics (CBGP, UPM-INIA), 28223, Pozuelo de Alarcón (Madrid), Spain
| | - Péter Szövényi
- Department of Systematic and Evolutionary Botany, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
| | | | - Lisa DeGironimo
- Department of Biology, College of Arts and Science, New York University, New York, New York, 10003, USA
| | - Sandra K Floyd
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - David J Beerling
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Michael K Deyholos
- Department of Biology, University of British Columbia, Kelowna, British Columbia, V1V 1V7, Canada
| | - Matt von Konrat
- Field Museum of Natural History, Chicago, Illinois, 60605, USA
| | - Shona Ellis
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
| | - A Jonathan Shaw
- Department of Biology, Duke University, Durham, North Carolina, 27708, USA
| | - Tao Chen
- Shenzhen Fairy Lake Botanical Garden, Chinese Academy of Sciences, Shenzhen, Guangdong, 518004, China
| | - Gane K-S Wong
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, T6G 2E9, Canada
- Department of Medicine, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
- BGI-Shenzhen, Beishan Industrial Zone, Yantian District, Shenzhen, 518083, China
| | | | - Jeffrey D Palmer
- Department of Biology, Indiana University, Bloomington, Indiana, 47405, USA
| | - Sean W Graham
- Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
- UBC Botanical Garden and Centre for Plant Research, University of British Columbia, 6804 Marine Drive SW, Vancouver, British Columbia, V6T 1Z4, Canada
| |
Collapse
|
67
|
Maruyama S, Kim E. Evolution of Photosynthetic Eukaryotes; Current Opinion, Perplexity, and a New Perspective. Results Probl Cell Differ 2020; 69:337-351. [PMID: 33263878 DOI: 10.1007/978-3-030-51849-3_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The evolution of eukaryotic photosynthesis marked a major transition for life on Earth, profoundly impacting the atmosphere of the Earth and evolutionary trajectory of an array of life forms. There are about ten lineages of photosynthetic eukaryotes, including Chloroplastida, Rhodophyta, and Cryptophyta. Mechanistically, eukaryotic photosynthesis arose via a symbiotic merger between a host eukaryote and either a cyanobacterial or eukaryotic photosymbiont. There are, however, many aspects of this major evolutionary transition that remain unsettled. The field, so far, has been dominated by proposals formulated following the principle of parsimony, such as the Archaeplastida hypothesis, in which a taxonomic lineage is often conceptually recognized as an individual cell (or a distinct entity). Such an assumption could lead to confusion or unrealistic interpretation of discordant genomic and phenotypic data. Here, we propose that the free-living ancestors to the plastids may have originated from a diversified lineage of cyanobacteria that were prone to symbioses, akin to some modern-day algae such as the Symbiodiniaceae dinoflagellates and Chlorella-related algae that associate with a number of unrelated host eukaryotes. This scenario, which assumes the plurality of ancestral form, better explains relatively minor but important differences that are observed in the genomes of modern-day eukaryotic algal species. Such a non-typological (or population-aware) way of thinking seems to better-model empirical data, such as discordant phylogenies between plastid and host eukaryote genes.
Collapse
Affiliation(s)
- Shinichiro Maruyama
- Department of Ecological Developmental Adaptability Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
| | - Eunsoo Kim
- Division of Invertebrate Zoology & Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY, USA
| |
Collapse
|
68
|
Responses of unicellular predators to cope with the phototoxicity of photosynthetic prey. Nat Commun 2019; 10:5606. [PMID: 31811209 PMCID: PMC6898599 DOI: 10.1038/s41467-019-13568-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 11/14/2019] [Indexed: 12/22/2022] Open
Abstract
Feeding on unicellular photosynthetic organisms by unicellular eukaryotes is the base of the aquatic food chain and evolutionarily led to the establishment of photosynthetic endosymbionts/organelles. Photosynthesis generates reactive oxygen species and damages cells; thus, photosynthetic organisms possess several mechanisms to cope with the stress. Here, we demonstrate that photosynthetic prey also exposes unicellular amoebozoan and excavates predators to photosynthetic oxidative stress. Upon illumination, there is a commonality in transcriptomic changes among evolutionarily distant organisms feeding on photosynthetic prey. One of the genes commonly upregulated is a horizontally transferred homolog of algal and plant genes for chlorophyll degradation/detoxification. In addition, the predators reduce their phagocytic uptake while accelerating digestion of photosynthetic prey upon illumination, reducing the number of photosynthetic cells inside the predator cells, as this also occurs in facultative endosymbiotic associations upon certain stresses. Thus, some mechanisms in predators observed here probably have been necessary for evolution of endosymbiotic associations. Photosynthesis generates reactive oxygen species that can damage cells. Here, the authors show that unicellular predators of photosynthetic prey have shared responses to photosynthetic oxidative stress and these may also have been important for the evolution of endosymbiosis.
Collapse
|
69
|
Wei C, Wang H, Ma M, Hu Q, Gong Y. Factors Affecting the Mixotrophic Flagellate Poterioochromonas malhamensis Grazing on Chlorella Cells. J Eukaryot Microbiol 2019; 67:190-202. [PMID: 31674079 DOI: 10.1111/jeu.12770] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 09/29/2019] [Accepted: 10/16/2019] [Indexed: 01/27/2023]
Abstract
Grazing behaviour between protozoa and phytoplankton exists widely in planktonic ecosystems. Poterioochromonas malhamensis is a well-known and widespread mixotrophic flagellate, which is recognized to play an important role within marine and freshwater planktonic ecosystems and regarded as the greatest contamination threat for mass algal cultures of Chlorella. In this study, a comprehensive range of factors, including morphological characters, biochemical compositions, and specific growth rate of ten species or strains of Chlorella, were evaluated for their effect on the feeding ability of P. malhamensis, which was assessed by two parameters: the clearance rate of P. malhamensis on Chlorella spp. and the specific growth rate of P. malhamensis. The results showed that the clearance rate of P. malhamensis was negatively correlated with cell wall thickness and specific growth rate of Chlorella spp., while the specific growth rate of P. malhamensis was positively correlated with carbohydrate percentage and C/N ratio and negatively correlated with protein, lipid percentage, and nitrogen mass. In conclusion, the factors influencing feeding selectivity include not only the morphological character and chemical composition of Chlorella, but also its population dynamics. Our study provides useful insights into the key factors that affect the feeding selectivity of P. malhamensis and provides basic and constructive data to help in screening for grazing-resistant microalgae.
Collapse
Affiliation(s)
- Chaojun Wei
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Hongxia Wang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Mingyang Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,SDIC Microalgae Biotechnology Center, SDIC Biotech Investment Co., LTD., Beijing, 065200, China.,Beijing Key Laboratory of Algae Biomass, Beijing, 100142, China
| | - Yingchun Gong
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.,Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| |
Collapse
|
70
|
Burki F, Roger AJ, Brown MW, Simpson AGB. The New Tree of Eukaryotes. Trends Ecol Evol 2019; 35:43-55. [PMID: 31606140 DOI: 10.1016/j.tree.2019.08.008] [Citation(s) in RCA: 391] [Impact Index Per Article: 78.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 01/01/2023]
Abstract
For 15 years, the eukaryote Tree of Life (eToL) has been divided into five to eight major groupings, known as 'supergroups'. However, the tree has been profoundly rearranged during this time. The new eToL results from the widespread application of phylogenomics and numerous discoveries of major lineages of eukaryotes, mostly free-living heterotrophic protists. The evidence that supports the tree has transitioned from a synthesis of molecular phylogenetics and biological characters to purely molecular phylogenetics. Most current supergroups lack defining morphological or cell-biological characteristics, making the supergroup label even more arbitrary than before. Going forward, the combination of traditional culturing with maturing culture-free approaches and phylogenomics should accelerate the process of completing and resolving the eToL at its deepest levels.
Collapse
Affiliation(s)
- Fabien Burki
- Department of Organismal Biology, Program in Systematic Biology, Uppsala University, Uppsala, Sweden; Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| | - Andrew J Roger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada; Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada
| | - Matthew W Brown
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA; Institute for Genomics, Biocomputing, and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - Alastair G B Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada; Department of Biology, Dalhousie University, Halifax, NS, Canada.
| |
Collapse
|
71
|
Keeling PJ. Combining morphology, behaviour and genomics to understand the evolution and ecology of microbial eukaryotes. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190085. [PMID: 31587641 DOI: 10.1098/rstb.2019.0085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Microbial eukaryotes (protists) are structurally, developmentally and behaviourally more complex than their prokaryotic cousins. This complexity makes it more difficult to translate genomic and metagenomic data into accurate functional inferences about systems ranging all the way from molecular and cellular levels to global ecological networks. This problem can be traced back to the advent of the cytoskeleton and endomembrane systems at the origin of eukaryotes, which endowed them with a range of complex structures and behaviours that still largely dominate how they evolve and interact within microbial communities. But unlike the diverse metabolic properties that evolved within prokaryotes, the structural and behavioural characteristics that strongly define how protists function in the environment cannot readily be inferred from genomic data, since there is generally no simple correlation between a gene and a discrete activity or function. A deeper understanding of protists at both cellular and ecological levels, therefore, requires not only high-throughput genomics but also linking such data to direct observations of natural history and cell biology. This is challenging since these observations typically require cultivation, which is lacking for most protists. Potential remedies with current technology include developing a more phylogenetically diverse range of model systems to better represent the diversity, as well as combining high-throughput, single-cell genomics with microscopic documentation of the subject cells to link sequence with structure and behaviour. This article is part of a discussion meeting issue 'Single cell ecology'.
Collapse
Affiliation(s)
- Patrick J Keeling
- Botany Department, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4
| |
Collapse
|
72
|
Husnik F, Keeling PJ. The fate of obligate endosymbionts: reduction, integration, or extinction. Curr Opin Genet Dev 2019; 58-59:1-8. [DOI: 10.1016/j.gde.2019.07.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/16/2019] [Accepted: 07/21/2019] [Indexed: 11/29/2022]
|