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George EE, Barcytė D, Lax G, Livingston S, Tashyreva D, Husnik F, Lukeš J, Eliáš M, Keeling PJ. A single cryptomonad cell harbors a complex community of organelles, bacteria, a phage, and selfish elements. Curr Biol 2023; 33:1982-1996.e4. [PMID: 37116483 DOI: 10.1016/j.cub.2023.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/20/2023] [Accepted: 04/06/2023] [Indexed: 04/30/2023]
Abstract
Symbiosis between prokaryotes and microbial eukaryotes (protists) has broadly impacted both evolution and ecology. Endosymbiosis led to mitochondria and plastids, the latter spreading across the tree of eukaryotes by subsequent rounds of endosymbiosis. Present-day endosymbionts in protists remain both common and diverse, although what function they serve is often unknown. Here, we describe a highly complex community of endosymbionts and a bacteriophage (phage) within a single cryptomonad cell. Cryptomonads are a model for organelle evolution because their secondary plastid retains a relict endosymbiont nucleus, but only one previously unidentified Cryptomonas strain (SAG 25.80) is known to harbor bacterial endosymbionts. We carried out electron microscopy and FISH imaging as well as genomic sequencing on Cryptomonas SAG 25.80, which revealed a stable, complex community even after over 50 years in continuous cultivation. We identified the host strain as Cryptomonas gyropyrenoidosa, and sequenced genomes from its mitochondria, plastid, and nucleomorph (and partially its nucleus), as well as two symbionts, Megaira polyxenophila and Grellia numerosa, and one phage (MAnkyphage) infecting M. polyxenophila. Comparing closely related endosymbionts from other hosts revealed similar metabolic and genomic features, with the exception of abundant transposons and genome plasticity in M. polyxenophila from Cryptomonas. We found an abundance of eukaryote-interacting genes as well as many toxin-antitoxin systems, including in the MAnkyphage genome that also encodes several eukaryotic-like proteins. Overall, the Cryptomonas cell is an endosymbiotic conglomeration with seven distinct evolving genomes that all show evidence of inter-lineage conflict but nevertheless remain stable, even after more than 4,000 generations in culture.
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Affiliation(s)
- Emma E George
- University of British Columbia, Department of Botany, Vancouver V6T 1Z4, Canada.
| | - Dovilė Barcytė
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, 701 00 Ostrava, Czech Republic; Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Gordon Lax
- University of British Columbia, Department of Botany, Vancouver V6T 1Z4, Canada
| | - Sam Livingston
- University of British Columbia, Department of Botany, Vancouver V6T 1Z4, Canada
| | - Daria Tashyreva
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic
| | - Filip Husnik
- Okinawa Institute of Science and Technology, Okinawa, 904-0495, Japan
| | - Julius Lukeš
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic; University of South Bohemia, Faculty of Sciences, 370 05 České Budějovice (Budweis), Czech Republic
| | - Marek Eliáš
- University of Ostrava, Faculty of Science, Department of Biology and Ecology, 701 00 Ostrava, Czech Republic
| | - Patrick J Keeling
- University of British Columbia, Department of Botany, Vancouver V6T 1Z4, Canada
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Gene loss, pseudogenization, and independent genome reduction in non-photosynthetic species of Cryptomonas (Cryptophyceae) revealed by comparative nucleomorph genomics. BMC Biol 2022; 20:227. [PMID: 36209116 PMCID: PMC9548191 DOI: 10.1186/s12915-022-01429-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/30/2022] [Indexed: 11/30/2022] Open
Abstract
Background Cryptophytes are ecologically important algae of interest to evolutionary cell biologists because of the convoluted history of their plastids and nucleomorphs, which are derived from red algal secondary endosymbionts. To better understand the evolution of the cryptophyte nucleomorph, we sequenced nucleomorph genomes from two photosynthetic and two non-photosynthetic species in the genus Cryptomonas. We performed a comparative analysis of these four genomes and the previously published genome of the non-photosynthetic species Cryptomonas paramecium CCAP977/2a. Results All five nucleomorph genomes are similar in terms of their general architecture, gene content, and gene order and, in the non-photosynthetic strains, loss of photosynthesis-related genes. Interestingly, in terms of size and coding capacity, the nucleomorph genome of the non-photosynthetic species Cryptomonas sp. CCAC1634B is much more similar to that of the photosynthetic C. curvata species than to the non-photosynthetic species C. paramecium. Conclusions Our results reveal fine-scale nucleomorph genome variation between distantly related congeneric taxa containing photosynthetic and non-photosynthetic species, including recent pseudogene formation, and provide a first glimpse into the possible impacts of the loss of photosynthesis on nucleomorph genome coding capacity and structure in independently evolved colorless strains. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01429-6.
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DeShaw AE, Figueroa‐Martinez F, Pröschold T, Lorenz M, Nedelcu AM, Smith DR, Reyes‐Prieto A. The plastomes of Hyalomonas oviformis and Hyalogonium fusiforme evolved dissimilar architectures after the loss of photosynthesis. PLANT DIRECT 2022; 6:e454. [PMID: 36311903 PMCID: PMC9598040 DOI: 10.1002/pld3.454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/25/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
The loss of photosynthesis in land plants and algae is typically associated with parasitism but can also occur in free-living species, including chlamydomonadalean green algae. The plastid genomes (ptDNAs) of colorless chlamydomonadaleans are surprisingly diverse in architecture, including highly expanded forms (Polytoma uvella and Leontynka pallida) as well as outright genome loss (Polytomella species). Here, we explore the ptDNAs of Hyalomonas (Hm.) oviformis (SAG 62-27; formerly known as Polytoma oviforme) and Hyalogonium (Hg.) fusiforme (SAG 62-1c), each representing independent losses of photosynthesis within the Chlamydophyceae. The Hm. oviformis ptDNA is moderately sized (132 kb) with a reduced gene complement (but still encoding the ATPase subunits) and is in fact smaller than that of its photosynthetic relative Hyalomonas chlamydogama SAG 11-48b (198.3 kb). The Hg. fusiforme plastome, however, is the largest yet observed in nonphotosynthetic plants or algae (~463 kb) and has a coding repertoire that is almost identical to that of its photosynthetic relatives in the genus Chlorogonium. Furthermore, the ptDNA of Hg. fusiforme shows no clear evidence of pseudogenization, which is consistent with our analyses showing that Hg. fusiforme is the nonphotosynthetic lineage of most recent origin among known colorless Chlamydophyceae. Together, these new ptDNAs clearly show that, in contrast to parasitic algae, plastid genome compaction is not an obligatory route following the loss of photosynthesis in free-living algae, and that certain chlamydomonadalean algae have a remarkable propensity for genomic expansion, which can persist regardless of the trophic strategy.
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Affiliation(s)
- Alexandra E. DeShaw
- Department of BiologyUniversity of New BrunswickFrederictonNew BrunswickCanada
| | | | - Thomas Pröschold
- Research Department for Limnology MondseeUniversity of InnsbruckInnsbruckAustria
| | - Maike Lorenz
- Experimental Phycology and Culture Collection of AlgaeUniversity of GöttingenGöttingenGermany
| | - Aurora M. Nedelcu
- Department of BiologyUniversity of New BrunswickFrederictonNew BrunswickCanada
| | - David R. Smith
- Department of BiologyWestern UniversityLondonOntarioCanada
| | - Adrián Reyes‐Prieto
- Department of BiologyUniversity of New BrunswickFrederictonNew BrunswickCanada
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Matsuo E, Morita K, Nakayama T, Yazaki E, Sarai C, Takahashi K, Iwataki M, Inagaki Y. Comparative Plastid Genomics of Green-Colored Dinoflagellates Unveils Parallel Genome Compaction and RNA Editing. FRONTIERS IN PLANT SCIENCE 2022; 13:918543. [PMID: 35898209 PMCID: PMC9309888 DOI: 10.3389/fpls.2022.918543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
Dinoflagellates possess plastids that are diverse in both pigmentation and evolutionary background. One of the plastid types found in dinoflagellates is pigmented with chlorophylls a and b (Chl a + b) and originated from the endosymbionts belonging to a small group of green algae, Pedinophyceae. The Chl a + b-containing plastids have been found in three distantly related dinoflagellates Lepidodinium spp., strain MGD, and strain TGD, and were proposed to be derived from separate partnerships between a dinoflagellate (host) and a pedinophycean green alga (endosymbiont). Prior to this study, a plastid genome sequence was only available for L. chlorophorum, which was reported to bear the features that were not found in that of the pedinophycean green alga Pedinomonas minor, a putative close relative of the endosymbiont that gave rise to the current Chl a + b-containing plastid. In this study, we sequenced the plastid genomes of strains MGD and TGD to compare with those of L. chlorophorum as well as pedinophycean green algae. The mapping of the RNA-seq reads on the corresponding plastid genome identified RNA editing on plastid gene transcripts in the three dinoflagellates. Further, the comparative plastid genomics revealed that the plastid genomes of the three dinoflagellates achieved several features, which are not found in or much less obvious than the pedinophycean plastid genomes determined to date, in parallel.
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Affiliation(s)
- Eriko Matsuo
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kounosuke Morita
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takuro Nakayama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| | | | - Chihiro Sarai
- Graduate School of Science and Engineering, Yamagata University, Yamagata, Japan
| | - Kazuya Takahashi
- Asian Natural Environmental Science Center, The University of Tokyo, Tokyo, Japan
| | - Mitsunori Iwataki
- Asian Natural Environmental Science Center, The University of Tokyo, Tokyo, Japan
| | - Yuji Inagaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
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Russell S, Jackson C, Reyes-Prieto A. High Sequence Divergence but Limited Architectural Rearrangements in Organelle Genomes of Cyanophora (Glaucophyta) Species. J Eukaryot Microbiol 2020; 68:e12831. [PMID: 33142007 DOI: 10.1111/jeu.12831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/16/2020] [Accepted: 10/27/2020] [Indexed: 11/29/2022]
Abstract
Cyanophora is the glaucophyte model taxon. Following the sequencing of the nuclear genome of C. paradoxa, studies based on single organelle and nuclear molecular markers revealed previously unrecognized species diversity within this glaucophyte genus. Here, we present the complete plastid (ptDNA) and mitochondrial (mtDNA) genomes of C. kugrensii, C. sudae, and C. biloba. The respective sizes and coding capacities of both ptDNAs and mtDNAs are conserved among Cyanophora species with only minor differences due to specific gene duplications. Organelle phylogenomic analyses consistently recover the species C. kugrensii and C. paradoxa as a clade and C. sudae and C. biloba as a separate group. The phylogenetic affiliations of the four Cyanophora species are consistent with architectural similarities shared at the organelle genomic level. Genetic distance estimations from both organelle sequences are also consistent with phylogenetic and architecture evidence. Comparative analyses confirm that the Cyanophora mitochondrial genes accumulate substitutions at 3-fold higher rates than plastid counterparts, suggesting that mtDNA markers are more appropriate to investigate glaucophyte diversity and evolutionary events that occur at a population level. The study of complete organelle genomes is becoming the standard for species delimitation and is particularly relevant to study cryptic diversity in microbial groups.
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Affiliation(s)
- Sarah Russell
- Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB, E3B 5A3, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Christopher Jackson
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Royal Botanic Gardens Victoria, Melbourne, Vic., Australia
| | - Adrian Reyes-Prieto
- Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB, E3B 5A3, Canada
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Kayama M, Maciszewski K, Yabuki A, Miyashita H, Karnkowska A, Kamikawa R. Highly Reduced Plastid Genomes of the Non-photosynthetic Dictyochophyceans Pteridomonas spp. (Ochrophyta, SAR) Are Retained for tRNA-Glu-Based Organellar Heme Biosynthesis. FRONTIERS IN PLANT SCIENCE 2020; 11:602455. [PMID: 33329672 PMCID: PMC7728698 DOI: 10.3389/fpls.2020.602455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/03/2020] [Indexed: 05/05/2023]
Abstract
Organisms that have lost their photosynthetic capabilities are present in a variety of eukaryotic lineages, such as plants and disparate algal groups. Most of such non-photosynthetic eukaryotes still carry plastids, as these organelles retain essential biological functions. Most non-photosynthetic plastids possess genomes with varied protein-coding contents. Such remnant plastids are known to be present in the non-photosynthetic, bacteriovorous alga Pteridomonas danica (Dictyochophyceae, Ochrophyta), which, regardless of its obligatory heterotrophic lifestyle, has been reported to retain the typically plastid-encoded gene for ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) large subunit (rbcL). The presence of rbcL without photosynthetic activity suggests that investigating the function of plastids in Pteridomonas spp. would likely bring unique insights into understanding the reductive evolution of plastids, their genomes, and plastid functions retained after the loss of photosynthesis. In this study, we demonstrate that two newly established strains of the non-photosynthetic genus Pteridomonas possess highly reduced plastid genomes lacking rbcL gene, in contrast to the previous report. Interestingly, we discovered that all plastid-encoded proteins in Pteridomonas spp. are involved only in housekeeping processes (e.g., transcription, translation and protein degradation), indicating that all metabolite synthesis pathways in their plastids are supported fully by nuclear genome-encoded proteins. Moreover, through an in-depth survey of the available transcriptomic data of another strain of the genus, we detected no candidate sequences for nuclear-encoded, plastid-directed Fe-S cluster assembly pathway proteins, suggesting complete loss of this pathway in the organelle, despite its widespread conservation in non-photosynthetic plastids. Instead, the transcriptome contains plastid-targeted components of heme biosynthesis, glycolysis, and pentose phosphate pathways. The retention of the plastid genomes in Pteridomonas spp. is not explained by the Suf-mediated constraint against loss of plastid genomes, previously proposed for Alveolates, as they lack Suf genes. Bearing all these findings in mind, we propose the hypothesis that plastid DNA is retained in Pteridomonas spp. for the purpose of providing glutamyl-tRNA, encoded by trnE gene, as a substrate for the heme biosynthesis pathway.
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Affiliation(s)
- Motoki Kayama
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Kacper Maciszewski
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Akinori Yabuki
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Hideaki Miyashita
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Anna Karnkowska
- Institute of Evolutionary Biology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
- *Correspondence: Anna Karnkowska,
| | - Ryoma Kamikawa
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- Ryoma Kamikawa,
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Kim JI, Jeong M, Archibald JM, Shin W. Comparative Plastid Genomics of Non-Photosynthetic Chrysophytes: Genome Reduction and Compaction. FRONTIERS IN PLANT SCIENCE 2020; 11:572703. [PMID: 33013997 PMCID: PMC7511666 DOI: 10.3389/fpls.2020.572703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/24/2020] [Indexed: 05/11/2023]
Abstract
Spumella-like heterotrophic chrysophytes are important eukaryotic microorganisms that feed on bacteria in aquatic and soil environments. They are characterized by their lack of pigmentation, naked cell surface, and extremely small size. Although Spumella-like chrysophytes have lost their photosynthetic ability, they still possess a leucoplast and retain a plastid genome. We have sequenced the plastid genomes of three non-photosynthetic chrysophytes, Spumella sp. Baeckdong012018B8, Pedospumella sp. Jangsampo120217C5 and Poteriospumella lacustris Yongseonkyo072317C3, and compared them to the previously sequenced plastid genome of "Spumella" sp. NIES-1846 and photosynthetic chrysophytes. We found the plastid genomes of Spumella-like flagellates to be generally conserved with respect to genome structure and housekeeping gene content. We nevertheless also observed lineage-specific gene rearrangements and duplication of partial gene fragments at the boundary of the inverted repeat and single copy regions. Most gene losses correspond to genes for proteins involved in photosynthesis and carbon fixation, except in the case of petF. The newly sequenced plastid genomes range from ~55.7 kbp to ~62.9 kbp in size and share a core set of 45 protein-coding genes, 3 rRNAs, and 32 to 34 tRNAs. Our results provide insight into the evolutionary history of organelle genomes via genome reduction and gene loss related to loss of photosynthesis in chrysophyte evolution.
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Affiliation(s)
- Jong Im Kim
- Department of Biology, Chungnam National University, Daejeon, South Korea
| | - Minseok Jeong
- Department of Biology, Chungnam National University, Daejeon, South Korea
| | - John M. Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Woongghi Shin
- Department of Biology, Chungnam National University, Daejeon, South Korea
- *Correspondence: Woongghi Shin,
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