1
|
Hoshino M, Cossard G, Haas FB, Kane EI, Kogame K, Jomori T, Wakimoto T, Glemin S, Coelho SM. Parallel loss of sexual reproduction in field populations of a brown alga sheds light on the mechanisms underlying the emergence of asexuality. Nat Ecol Evol 2024; 8:1916-1932. [PMID: 39152327 PMCID: PMC11461277 DOI: 10.1038/s41559-024-02490-w] [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: 02/01/2024] [Accepted: 06/18/2024] [Indexed: 08/19/2024]
Abstract
Sexual reproduction is widespread, but asexual lineages have repeatedly arisen from sexual ancestors across a wide range of eukaryotic taxa. The molecular changes underpinning the switch to asexuality remain elusive, particularly in organisms with haploid sexual systems. Here we explore independent events of loss of sex in the brown alga Scytosiphon, examine the proximate and evolutionary mechanisms involved, and test the importance of sexual conflict on gene expression changes following loss of sex. We find that asexual females ('Amazons') lose ability to produce sex pheromone and, consequently, are incapable of attracting males, whereas they gain rapid parthenogenic development from large, unfertilized eggs. These phenotypic changes are accompanied by convergent changes in gene expression. Decay of female functions, rather than relaxation of sexual antagonism, may be a dominant force at play during the emergence of asexuality in haploid sexual systems. Moreover, we show that haploid purifying selection plays a key role in limiting the accumulation of deleterious alleles in Amazons, and we identify an autosomal locus associated with the Amazon phenotype. The sex chromosome, together with this autosomal locus, may underlie the switch to obligate asexuality in the Amazon populations.
Collapse
Affiliation(s)
- Masakazu Hoshino
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
- Research Center for Inland Seas, Kobe University, Rokkodai 1-1, Nadaku, Kobe, Japan
| | - Guillaume Cossard
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Fabian B Haas
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Emma I Kane
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Kazuhiro Kogame
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Takahiro Jomori
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | | | - Sylvain Glemin
- Laboratoire ECOBIO (Ecosystèmes, biodiversité, évolution), UMR 6553, CNRS, Université de Rennes, Rennes, France
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany.
| |
Collapse
|
2
|
Dries E, Meyers Y, Liesner D, Gonzaga FM, Becker JFM, Zakka EE, Beeckman T, Coelho SM, De Clerck O, Bogaert KA. Cell wall-mediated maternal control of apical-basal patterning of the kelp Undaria pinnatifida. THE NEW PHYTOLOGIST 2024; 243:1887-1898. [PMID: 38984686 DOI: 10.1111/nph.19953] [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: 04/29/2024] [Accepted: 06/21/2024] [Indexed: 07/11/2024]
Abstract
The role of maternal tissue in embryogenesis remains enigmatic in many complex organisms. Here, we investigate the contribution of maternal tissue to apical-basal patterning in the kelp embryo. Focussing on Undaria pinnatifida, we studied the effects of detachment from the maternal tissue using microsurgery, staining of cell wall modifications, morphometric measurements, flow cytometry, genotyping and a modified kelp fertilisation protocol synchronising kelp embryogenesis. Detached embryos are rounder and often show aberrant morphologies. When a part of the oogonial cell wall remains attached to the zygote, the apical-basal patterning is rescued. Furthermore, the absence of contact with maternal tissue increases parthenogenesis, highlighting the critical role of maternal signals in the initial stages of development. These results show a key role for the connection to the maternal oogonial cell wall in apical-basal patterning in kelps. This observation is reminiscent of another brown alga, Fucus, where the cell wall directs the cell fate. Our findings suggest a conserved mechanism across phylogenetically distant oogamous lineages, where localised secretion of sulphated F2 fucans mediates the establishment of the apical-basal polarity. In this model, the maternal oogonial cell wall mediates basal cell fate determination by providing an extrinsic patterning cue to the future kelp embryo.
Collapse
Affiliation(s)
- Eloise Dries
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
- Laboratory of Cell and Developmental Biology, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708 PB, the Netherlands
| | - Yannick Meyers
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
| | - Daniel Liesner
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Max-Planck-Ring 5, Tübingen, 72076, Germany
| | - Floriele M Gonzaga
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
| | - Jakob F M Becker
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
| | - Eliane E Zakka
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
| | - Tom Beeckman
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, B-9052, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Max-Planck-Ring 5, Tübingen, 72076, Germany
| | - Olivier De Clerck
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
| | - Kenny A Bogaert
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, Ghent, B-9000, Belgium
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Max-Planck-Ring 5, Tübingen, 72076, Germany
| |
Collapse
|
3
|
Luthringer R, Raphalen M, Guerra C, Colin S, Martinho C, Zheng M, Hoshino M, Badis Y, Lipinska AP, Haas FB, Barrera-Redondo J, Alva V, Coelho SM. Repeated co-option of HMG-box genes for sex determination in brown algae and animals. Science 2024; 383:eadk5466. [PMID: 38513029 DOI: 10.1126/science.adk5466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/31/2024] [Indexed: 03/23/2024]
Abstract
In many eukaryotes, genetic sex determination is not governed by XX/XY or ZW/ZZ systems but by a specialized region on the poorly studied U (female) or V (male) sex chromosomes. Previous studies have hinted at the existence of a dominant male-sex factor on the V chromosome in brown algae, a group of multicellular eukaryotes distantly related to animals and plants. The nature of this factor has remained elusive. Here, we demonstrate that an HMG-box gene acts as the male-determining factor in brown algae, mirroring the role HMG-box genes play in sex determination in animals. Over a billion-year evolutionary timeline, these lineages have independently co-opted the HMG box for male determination, representing a paradigm for evolution's ability to recurrently use the same genetic "toolkit" to accomplish similar tasks.
Collapse
Affiliation(s)
- Rémy Luthringer
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Morgane Raphalen
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Carla Guerra
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Sébastien Colin
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Claudia Martinho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Min Zheng
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Masakazu Hoshino
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
- Research Center for Inland Seas, Kobe University, Kobe 658-0022, Japan
| | - Yacine Badis
- Roscoff Biological Station, CNRS-Sorbonne University, Place Georges Teissier, 29680 Roscoff, France
| | - Agnieszka P Lipinska
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Fabian B Haas
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Josué Barrera-Redondo
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| |
Collapse
|
4
|
Bessho K. Stable demographic ratios of haploid gametophyte to diploid sporophyte abundance in macroalgal populations. PLoS One 2024; 19:e0295409. [PMID: 38451989 PMCID: PMC10919683 DOI: 10.1371/journal.pone.0295409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 11/22/2023] [Indexed: 03/09/2024] Open
Abstract
Macroalgal populations often consist of free-living haploid (gametophyte) and diploid (sporophyte) stages. Various ecological studies have been conducted to examine the demographic diversity of haploid-diploid populations with regard to the dominant stage. Here, I relaxed the assumption of classical research that the life history parameters of haploids and diploids are identical and developed a generalized haploid-diploid model that explicitly accounts for population density dependence and asexual reproduction. Analysis of this model yielded an exact solution for the abundance ratio of haploids to diploids in a population in which the ratio is determined by the balance of four demographic forces: sexual reproduction by haploids, sexual reproduction by diploids, asexual reproduction by haploids, and asexual reproduction by diploids. Furthermore, the persistence of a haploid-diploid population and its total biomass are shown to be determined by the basic reproductive number (R0), which is shown to be a function of these four demographic forces. When R0 is greater than one, the haploid-diploid population stably persists, and the ploidy ratio obtained by the analytical solution is realized.
Collapse
|
5
|
Krasovec M, Hoshino M, Zheng M, Lipinska AP, Coelho SM. Low Spontaneous Mutation Rate in Complex Multicellular Eukaryotes with a Haploid-Diploid Life Cycle. Mol Biol Evol 2023; 40:msad105. [PMID: 37140022 PMCID: PMC10254074 DOI: 10.1093/molbev/msad105] [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: 03/09/2023] [Revised: 04/22/2023] [Accepted: 05/01/2023] [Indexed: 05/05/2023] Open
Abstract
The spontaneous mutation rate µ is a crucial parameter to understand evolution and biodiversity. Mutation rates are highly variable across species, suggesting that µ is susceptible to selection and drift and that species life cycle and life history may impact its evolution. In particular, asexual reproduction and haploid selection are expected to affect the mutation rate, but very little empirical data are available to test this expectation. Here, we sequence 30 genomes of a parent-offspring pedigree in the model brown alga Ectocarpus sp.7, and 137 genomes of an interspecific cross of the closely related brown alga Scytosiphon to have access to the spontaneous mutation rate of representative organisms of a complex multicellular eukaryotic lineage outside animals and plants, and to evaluate the potential impact of life cycle on the mutation rate. Brown algae alternate between a haploid and a diploid stage, both multicellular and free living, and utilize both sexual and asexual reproduction. They are, therefore, excellent models to empirically test expectations of the effect of asexual reproduction and haploid selection on mutation rate evolution. We estimate that Ectocarpus has a base substitution rate of µbs = 4.07 × 10-10 per site per generation, whereas the Scytosiphon interspecific cross had µbs = 1.22 × 10-9. Overall, our estimations suggest that these brown algae, despite being multicellular complex eukaryotes, have unusually low mutation rates. In Ectocarpus, effective population size (Ne) could not entirely explain the low µbs. We propose that the haploid-diploid life cycle, combined with extensive asexual reproduction, may be additional key drivers of the mutation rate in these organisms.
Collapse
Affiliation(s)
- Marc Krasovec
- Sorbonne Université, CNRS, UMR 7232 Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, Banyuls-sur-Mer, France
| | - Masakazu Hoshino
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Min Zheng
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Agnieszka P Lipinska
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| |
Collapse
|
6
|
Godfroy O, Zheng M, Yao H, Henschen A, Peters AF, Scornet D, Colin S, Ronchi P, Hipp K, Nagasato C, Motomura T, Cock JM, Coelho SM. The baseless mutant links protein phosphatase 2A with basal cell identity in the brown alga Ectocarpus. Development 2023; 150:dev201283. [PMID: 36786333 PMCID: PMC10112911 DOI: 10.1242/dev.201283] [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: 09/15/2022] [Accepted: 01/16/2023] [Indexed: 02/15/2023]
Abstract
The first mitotic division of the initial cell is a key event in all multicellular organisms and is associated with the establishment of major developmental axes and cell fates. The brown alga Ectocarpus has a haploid-diploid life cycle that involves the development of two multicellular generations: the sporophyte and the gametophyte. Each generation deploys a distinct developmental programme autonomously from an initial cell, the first cell division of which sets up the future body pattern. Here, we show that mutations in the BASELESS (BAS) gene result in multiple cellular defects during the first cell division and subsequent failure to produce basal structures during both generations. BAS encodes a type B″ regulatory subunit of protein phosphatase 2A (PP2A), and transcriptomic analysis identified potential effector genes that may be involved in determining basal cell fate. The bas mutant phenotype is very similar to that observed in distag (dis) mutants, which lack a functional Tubulin-binding co-factor Cd1 (TBCCd1) protein, indicating that TBCCd1 and PP2A are two essential components of the cellular machinery that regulates the first cell division and mediates basal cell fate determination.
Collapse
Affiliation(s)
- Olivier Godfroy
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Min Zheng
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Haiqin Yao
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Agnes Henschen
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | | | - Delphine Scornet
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Sebastien Colin
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Katharina Hipp
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - J. Mark Cock
- Laboratory of Integrative Biology of Marine Models, Sorbonne Université, UPMC University of Paris 06, CNRS, UMR 8227, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Susana M. Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| |
Collapse
|
7
|
Bogaert KA, Zakka EE, Coelho SM, De Clerck O. Polarization of brown algal zygotes. Semin Cell Dev Biol 2023; 134:90-102. [PMID: 35317961 DOI: 10.1016/j.semcdb.2022.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 11/29/2022]
Abstract
Brown algae are a group of multicellular, heterokont algae that have convergently evolved developmental complexity that rivals that of embryophytes, animals or fungi. Early in development, brown algal zygotes establish a basal and an apical pole, which will become respectively the basal system (holdfast) and the apical system (thallus) of the adult alga. Brown algae are interesting models for understanding the establishment of cell polarity in a broad evolutionary context, because they exhibit a large diversity of life cycles, reproductive strategies and, importantly, their zygotes are produced in large quantities free of parental tissue, with symmetry breaking and asymmetric division taking place in a highly synchronous manner. This review describes the current knowledge about the establishment of the apical-basal axis in the model brown seaweeds Ectocarpus, Dictyota, Fucus and Saccharina, highlighting the advantages and specific interests of each system. Ectocarpus is a genetic model system that allows access to the molecular basis of early development and life-cycle control over apical-basal polarity. The oogamous brown alga Fucus, together with emerging comparative models Dictyota and Saccharina, emphasize the diversity of strategies of symmetry breaking in determining a cell polarity vector in brown algae. A comparison with symmetry-breaking mechanisms in land plants, animals and fungi, reveals that the one-step zygote polarisation of Fucus compares well to Saccharomyces budding and Arabidopsis stomata development, while the two-phased symmetry breaking in the Dictyota zygote compares to Schizosaccharomyces fission, the Caenorhabditis anterior-posterior zygote polarisation and Arabidopsis prolate pollen polarisation. The apical-basal patterning in Saccharina zygotes on the other hand, may be seen as analogous to that of land plants. Overall, brown algae have the potential to bring exciting new information on how a single cell gives rise to an entire complex body plan.
Collapse
Affiliation(s)
- Kenny A Bogaert
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium.
| | - Eliane E Zakka
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
| | - Susana M Coelho
- Department of Algal Development and Evolution, Max Planck Institute for Biology, Tübingen, Germany
| | - Olivier De Clerck
- Phycology Research Group, Department of Biology, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium
| |
Collapse
|
8
|
Goecke F, Gómez Garreta A, Martín-Martín R, Rull Lluch J, Skjermo J, Ergon Å. Nuclear DNA Content Variation in Different Life Cycle Stages of Sugar Kelp, Saccharina latissima. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:706-721. [PMID: 35882688 PMCID: PMC9385784 DOI: 10.1007/s10126-022-10137-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Ploidy variants can be utilized to increase yield, introduce sterility, and modify specific traits with an economic impact. Despite economic importance of Saccharina species, their nuclear DNA content in different cell types and life stages remain unclear. The present research was initiated to determine the nuclear DNA content and intraindividual variation at different life cycle stages of the Laminarialean kelp Saccharina latissima. Nuclear DNA content in embryonic and mature sporophytes, released and unreleased zoospores, female, and male gametophytes from Sør-Trøndelag county in Norway were estimated by image analysis using the DNA-localizing fluorochrome DAPI and chicken's red blood cells as a standard. DNA content of a total of 6905 DAPI-stained nuclei was estimated. This is the first study of nuclear DNA content which covered the life cycle of kelp. The lowest level of DNA content (1C) was observed in zoospores with an average of 0.76 pg. Male and female single spore gametophyte cultures presented higher average DNA content, more than double that of zoospores, suggesting the presence of polyteny. Female gametophyte nuclei were slightly larger and more variable in size than those of male gametophytes. The DNA content observed in embryonic sporophytes and in meristoderm cells from older sporophytes (1.51 pg) was 2C as expected and in the range of previously published studies of sporophytes of S. latissima. Mature sporophytes showed intra-plant variation with DNA content values ranging from 2-16C. The main difference was between meristoderm cells (mostly 2C) and cortical and medullary cells (2-16C).
Collapse
Affiliation(s)
- Franz Goecke
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway.
| | - Amelia Gómez Garreta
- Laboratori de Botànica, Facultat de Farmàcia I Ciències de L'Alimentació, Institut de Recerca de La Biodiversitat (IRBio) & Centre de Documentació de Biodiversitat Vegetal (CeDocBiV), Universitat de Barcelona, Barcelona, Spain
| | - Rafael Martín-Martín
- Laboratori de Botànica, Facultat de Farmàcia I Ciències de L'Alimentació, Institut de Recerca de La Biodiversitat (IRBio) & Centre de Documentació de Biodiversitat Vegetal (CeDocBiV), Universitat de Barcelona, Barcelona, Spain
| | - Jordi Rull Lluch
- Laboratori de Botànica, Facultat de Farmàcia I Ciències de L'Alimentació, Institut de Recerca de La Biodiversitat (IRBio) & Centre de Documentació de Biodiversitat Vegetal (CeDocBiV), Universitat de Barcelona, Barcelona, Spain
| | - Jorunn Skjermo
- Department of Fisheries and New Biomarine Industries, SINTEF Ocean, Trondheim, Norway
| | - Åshild Ergon
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, Norway
| |
Collapse
|
9
|
Coelho SM, Umen J. Switching it up: algal insights into sexual transitions. PLANT REPRODUCTION 2021; 34:287-296. [PMID: 34181073 PMCID: PMC8566403 DOI: 10.1007/s00497-021-00417-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/02/2021] [Indexed: 05/03/2023]
Abstract
While the process of meiosis is highly conserved across eukaryotes, the sexual systems that govern life cycle phase transitions are surprisingly labile. Switches between sexual systems have profound evolutionary and ecological consequences, in particular for plants, but our understanding of the fundamental mechanisms and ultimate causes underlying these transitions is still surprisingly incomplete. We explore here the idea that brown and green algae may be interesting comparative models that can increase our understanding of relevant processes in plant reproductive biology, from evolution of gamete dimorphism, gametogenesis, sex determination and transitions in sex-determining systems.
Collapse
Affiliation(s)
- Susana M Coelho
- Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany.
| | - James Umen
- Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| |
Collapse
|
10
|
Vigneau J, Borg M. The epigenetic origin of life history transitions in plants and algae. PLANT REPRODUCTION 2021; 34:267-285. [PMID: 34236522 PMCID: PMC8566409 DOI: 10.1007/s00497-021-00422-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/14/2021] [Indexed: 05/17/2023]
Abstract
Plants and algae have a complex life history that transitions between distinct life forms called the sporophyte and the gametophyte. This phenomenon-called the alternation of generations-has fascinated botanists and phycologists for over 170 years. Despite the mesmerizing array of life histories described in plants and algae, we are only now beginning to learn about the molecular mechanisms controlling them and how they evolved. Epigenetic silencing plays an essential role in regulating gene expression during multicellular development in eukaryotes, raising questions about its impact on the life history strategy of plants and algae. Here, we trace the origin and function of epigenetic mechanisms across the plant kingdom, from unicellular green algae through to angiosperms, and attempt to reconstruct the evolutionary steps that influenced life history transitions during plant evolution. Central to this evolutionary scenario is the adaption of epigenetic silencing from a mechanism of genome defense to the repression and control of alternating generations. We extend our discussion beyond the green lineage and highlight the peculiar case of the brown algae. Unlike their unicellular diatom relatives, brown algae lack epigenetic silencing pathways common to animals and plants yet display complex life histories, hinting at the emergence of novel life history controls during stramenopile evolution.
Collapse
Affiliation(s)
- Jérômine Vigneau
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany.
| |
Collapse
|
11
|
Müller DG, Gaschet E, Godfroy O, Gueno J, Cossard G, Kunert M, Peters AF, Westermeier R, Boland W, Cock JM, Lipinska AP, Coelho SM. A partially sex-reversed giant kelp sheds light into the mechanisms of sexual differentiation in a UV sexual system. THE NEW PHYTOLOGIST 2021; 232:252-263. [PMID: 34166525 DOI: 10.1111/nph.17582] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
In UV sexual systems, sex is determined during the haploid phase of the life cycle and males have a V chromosome whereas females have a U chromosome. Previous work in the brown alga Ectocarpus revealed that the V chromosome has a dominant role in male sex determination and suggested that the female developmental programme may occur by 'default'. Here, we describe the identification of a genetically male giant kelp strain presenting phenotypic features typical of a female, despite lacking the U-specific region. The conversion to the female developmental programme is however incomplete, because gametes of this feminized male are unable to produce the sperm-attracting pheromone lamoxirene. We identify the transcriptomic patterns underlying the male and female specific developmental programmes, and show that the phenotypic feminization is associated with both feminization and de-masculinization of gene expression patterns. Importantly, the feminization phenotype was associated with dramatic downregulation of two V-specific genes including a candidate male-determining gene. Our results reveal the transcriptional changes associated with sexual differentiation in a UV system, and contribute to disentangling the role of sex-linked and autosomal gene expression in the initiation of sex-specific developmental programmes. Overall, the data presented here imply that the U-specific region is not required to initiate the female developmental programme, but is critical to produce fully functional eggs, arguing against the idea that female is the 'default' sex in this species.
Collapse
Affiliation(s)
- Dieter G Müller
- Fachbereich Biologie der Universität Konstanz, Konstanz, 78457, Germany
| | - Enora Gaschet
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
| | - Olivier Godfroy
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
| | - Josselin Gueno
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
| | - Guillaume Cossard
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
| | - Maritta Kunert
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
| | | | - Renato Westermeier
- Instituto de Acuicultura, Universidad Austral de Chile, Casilla 1327, Puerto Montt, Chile
| | - Wilhelm Boland
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
| | - J Mark Cock
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
| | - Agnieszka P Lipinska
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
- Max Plank Institute for Developmental Biology, Tübingen, Germany
| | - Susana M Coelho
- UPMC Univ Paris 06, CNRS, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, Roscoff, CS 90074, F-29688, France
- Max Plank Institute for Developmental Biology, Tübingen, Germany
| |
Collapse
|
12
|
Badis Y, Scornet D, Harada M, Caillard C, Godfroy O, Raphalen M, Gachon CMM, Coelho SM, Motomura T, Nagasato C, Cock JM. Targeted CRISPR-Cas9-based gene knockouts in the model brown alga Ectocarpus. THE NEW PHYTOLOGIST 2021; 231:2077-2091. [PMID: 34076889 DOI: 10.1111/nph.17525] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Brown algae are an important group of multicellular eukaryotes, phylogenetically distinct from both the animal and land plant lineages. Ectocarpus has emerged as a model organism to study diverse aspects of brown algal biology, but this system currently lacks an effective reverse genetics methodology to analyse the functions of selected target genes. Here, we report that mutations at specific target sites are generated following the introduction of CRISPR-Cas9 ribonucleoproteins into Ectocarpus cells, using either biolistics or microinjection as the delivery method. Individuals with mutations affecting the ADENINE PHOSPHORIBOSYL TRANSFERASE (APT) gene were isolated following treatment with 2-fluoroadenine, and this selection system was used to isolate individuals in which mutations had been introduced simultaneously at APT and at a second gene. This double mutation approach could potentially be used to isolate mutants affecting any Ectocarpus gene, providing an effective reverse genetics tool for this model organism. The availability of this tool will significantly enhance the utility of Ectocarpus as a model organism for this ecologically and economically important group of marine organisms. Moreover, the methodology described here should be readily transferable to other brown algal species.
Collapse
Affiliation(s)
- Yacine Badis
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll,, PA37 1QA, UK
| | - Delphine Scornet
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Minori Harada
- Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Céline Caillard
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Olivier Godfroy
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Morgane Raphalen
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Claire M M Gachon
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll,, PA37 1QA, UK
- UMR 7245 Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 54, 57 rue Cuvier, Paris, 75005, France
| | - Susana M Coelho
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, Tübingen, 72076, Germany
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - J Mark Cock
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| |
Collapse
|
13
|
Heesch S, Serrano-Serrano M, Barrera-Redondo J, Luthringer R, Peters AF, Destombe C, Cock JM, Valero M, Roze D, Salamin N, Coelho SM. Evolution of life cycles and reproductive traits: Insights from the brown algae. J Evol Biol 2021; 34:992-1009. [PMID: 34096650 DOI: 10.1101/530477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/18/2021] [Indexed: 05/28/2023]
Abstract
A vast diversity of types of life cycles exists in nature, and several theories have been advanced to explain how this diversity has evolved and how each type of life cycle is retained over evolutionary time. Here, we exploited the diversity of life cycles and reproductive traits of the brown algae (Phaeophyceae) to test several hypotheses on the evolution of life cycles. We investigated the evolutionary dynamics of four life-history traits: life cycle, sexual system, level of gamete dimorphism and gamete parthenogenetic capacity. We assigned states to up to 77 representative species of the taxonomic diversity of the brown algal group, in a multi-gene phylogeny. We used maximum likelihood and Bayesian analyses of correlated evolution, while taking the phylogeny into account, to test for correlations between traits and to investigate the chronological sequence of trait acquisition. Our analyses are consistent with the prediction that diploid growth evolves when sexual reproduction is preferred over asexual reproduction, possibly because it allows the complementation of deleterious mutations. We also found that haploid sex determination is ancestral in relation to diploid sex determination. However, our results could not address whether increased zygotic and diploid growth are associated with increased sexual dimorphism. Our analyses suggest that in the brown algae, isogamous species evolved from anisogamous ancestors, contrary to the commonly reported pattern where evolution proceeds from isogamy to anisogamy.
Collapse
Affiliation(s)
- Svenja Heesch
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
- Applied Ecology & Phycology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | | | - Josué Barrera-Redondo
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Rémy Luthringer
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
| | | | - Christophe Destombe
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - J Mark Cock
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
| | - Myriam Valero
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - Denis Roze
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - Nicolas Salamin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Susana M Coelho
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| |
Collapse
|
14
|
Heesch S, Serrano-Serrano M, Barrera-Redondo J, Luthringer R, Peters AF, Destombe C, Cock JM, Valero M, Roze D, Salamin N, Coelho SM. Evolution of life cycles and reproductive traits: Insights from the brown algae. J Evol Biol 2021; 34:992-1009. [PMID: 34096650 DOI: 10.1111/jeb.13880] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/18/2021] [Indexed: 02/06/2023]
Abstract
A vast diversity of types of life cycles exists in nature, and several theories have been advanced to explain how this diversity has evolved and how each type of life cycle is retained over evolutionary time. Here, we exploited the diversity of life cycles and reproductive traits of the brown algae (Phaeophyceae) to test several hypotheses on the evolution of life cycles. We investigated the evolutionary dynamics of four life-history traits: life cycle, sexual system, level of gamete dimorphism and gamete parthenogenetic capacity. We assigned states to up to 77 representative species of the taxonomic diversity of the brown algal group, in a multi-gene phylogeny. We used maximum likelihood and Bayesian analyses of correlated evolution, while taking the phylogeny into account, to test for correlations between traits and to investigate the chronological sequence of trait acquisition. Our analyses are consistent with the prediction that diploid growth evolves when sexual reproduction is preferred over asexual reproduction, possibly because it allows the complementation of deleterious mutations. We also found that haploid sex determination is ancestral in relation to diploid sex determination. However, our results could not address whether increased zygotic and diploid growth are associated with increased sexual dimorphism. Our analyses suggest that in the brown algae, isogamous species evolved from anisogamous ancestors, contrary to the commonly reported pattern where evolution proceeds from isogamy to anisogamy.
Collapse
Affiliation(s)
- Svenja Heesch
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
- Applied Ecology & Phycology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | | | - Josué Barrera-Redondo
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Rémy Luthringer
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
| | | | - Christophe Destombe
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - J Mark Cock
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
| | - Myriam Valero
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - Denis Roze
- Evolutionary Biology and Ecology of Algae, CNRS, Sorbonne Université, UC, UACH, IRL 3614, Roscoff, France
| | - Nicolas Salamin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Susana M Coelho
- CNRS, Algal Genetics Group, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Université, UPMC Univ Paris 06, Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany
| |
Collapse
|
15
|
Yao H, Scornet D, Jam M, Hervé C, Potin P, Oliveira Correia L, Coelho SM, Cock JM. Biochemical characteristics of a diffusible factor that induces gametophyte to sporophyte switching in the brown alga Ectocarpus. JOURNAL OF PHYCOLOGY 2021; 57:742-753. [PMID: 33432598 DOI: 10.1111/jpy.13126] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
The haploid-diploid life cycle of the filamentous brown alga Ectocarpus involves alternation between two independent and morphologically distinct multicellular generations, the sporophyte and the gametophyte. Deployment of the sporophyte developmental program requires two TALE homeodomain transcription factors OUROBOROS and SAMSARA. In addition, the sporophyte generation has been shown to secrete a diffusible factor that can induce uni-spores to switch from the gametophyte to the sporophyte developmental program. Here, we determine optimal conditions for production, storage, and detection of this diffusible factor and show that it is a heat-resistant, high molecular weight molecule. Based on a combined approach involving proteomic analysis of sporophyte-conditioned medium and the use of biochemical tools to characterize arabinogalactan proteins, we present evidence that sporophyte-conditioned medium contains AGP epitopes and suggest that the diffusible factor may belong to this family of glycoproteins.
Collapse
Affiliation(s)
- Haiqin Yao
- Algal Genetics Group, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Delphine Scornet
- Algal Genetics Group, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Murielle Jam
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
- Marine Glycobiology, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
| | - Cécile Hervé
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
- Marine Glycobiology, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
| | - Philippe Potin
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
- Algal Biology and Environmental Interactions, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
| | - Lydie Oliveira Correia
- PAPPSO, INRA, AgroParisTech, Micalis Institute, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Susana M Coelho
- Algal Genetics Group, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - J Mark Cock
- Algal Genetics Group, UMR 8227, CNRS, Sorbonne Université, UPMC University Paris 06, Paris, France
- Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| |
Collapse
|
16
|
Bourdareau S, Tirichine L, Lombard B, Loew D, Scornet D, Wu Y, Coelho SM, Cock JM. Histone modifications during the life cycle of the brown alga Ectocarpus. Genome Biol 2021; 22:12. [PMID: 33397407 PMCID: PMC7784034 DOI: 10.1186/s13059-020-02216-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 12/02/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Brown algae evolved complex multicellularity independently of the animal and land plant lineages and are the third most developmentally complex phylogenetic group on the planet. An understanding of developmental processes in this group is expected to provide important insights into the evolutionary events necessary for the emergence of complex multicellularity. Here, we focus on mechanisms of epigenetic regulation involving post-translational modifications of histone proteins. RESULTS A total of 47 histone post-translational modifications are identified, including a novel mark H2AZR38me1, but Ectocarpus lacks both H3K27me3 and the major polycomb complexes. ChIP-seq identifies modifications associated with transcription start sites and gene bodies of active genes and with transposons. H3K79me2 exhibits an unusual pattern, often marking large genomic regions spanning several genes. Transcription start sites of closely spaced, divergently transcribed gene pairs share a common nucleosome-depleted region and exhibit shared histone modification peaks. Overall, patterns of histone modifications are stable through the life cycle. Analysis of histone modifications at generation-biased genes identifies a correlation between the presence of specific chromatin marks and the level of gene expression. CONCLUSIONS The overview of histone post-translational modifications in the brown alga presented here will provide a foundation for future studies aimed at understanding the role of chromatin modifications in the regulation of brown algal genomes.
Collapse
Affiliation(s)
- Simon Bourdareau
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Leila Tirichine
- Université de Nantes, CNRS, UFIP, UMR 6286, F-44000, Nantes, France
| | - Bérangère Lombard
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Delphine Scornet
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Yue Wu
- Université de Nantes, CNRS, UFIP, UMR 6286, F-44000, Nantes, France
| | - Susana M Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France.
- Current address: Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany.
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France.
| |
Collapse
|
17
|
Yao H, Scornet D, Badis Y, Peters AF, Jam M, Hervé C, Potin P, Coelho SM, Cock JM. Production and Bioassay of a Diffusible Factor That Induces Gametophyte-to-Sporophyte Developmental Reprogramming in the Brown Alga Ectocarpus. Bio Protoc 2020; 10:e3753. [PMID: 33659412 DOI: 10.21769/bioprotoc.3753] [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: 03/29/2020] [Revised: 07/13/2020] [Accepted: 07/29/2020] [Indexed: 11/02/2022] Open
Abstract
The brown alga Ectocarpus has a haploid-diploid life cycle that involves alternation between two multicellular generations, the sporophyte and the gametophyte. Life cycle generation is not determined by ploidy but by a genetic system that includes two different three amino acid loop extension homeodomain transcription factors called OUROBOROS and SAMSARA. In addition, sporophytes have been shown to secrete a diffusible factor into the medium that can induce gametophyte initial cells to switch from the gametophyte to the sporophyte developmental program. The protocol presented here describes how to produce sporophyte-conditioned medium containing the diffusible sporophyte-inducing factor and how to assay for activity of the factor using a meio-spore-based bioassay. The protocol, which describes how several steps of these procedures can be optimised, will represent a useful tool for future work aimed at characterising the diffusible factor and investigating its mode of action.
Collapse
Affiliation(s)
- Haiqin Yao
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Delphine Scornet
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Yacine Badis
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France.,The Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, United Kingdom
| | | | - Murielle Jam
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Cécile Hervé
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Philippe Potin
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Susana M Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| |
Collapse
|
18
|
|
19
|
Coelho SM, Peters AF, Müller D, Cock JM. Ectocarpus: an evo-devo model for the brown algae. EvoDevo 2020; 11:19. [PMID: 32874530 PMCID: PMC7457493 DOI: 10.1186/s13227-020-00164-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022] Open
Abstract
Ectocarpus is a genus of filamentous, marine brown algae. Brown algae belong to the stramenopiles, a large supergroup of organisms that are only distantly related to animals, land plants and fungi. Brown algae are also one of only a small number of eukaryotic lineages that have evolved complex multicellularity. For many years, little information was available concerning the molecular mechanisms underlying multicellular development in the brown algae, but this situation has changed with the emergence of Ectocarpus as a model brown alga. Here we summarise some of the main questions that are being addressed and areas of study using Ectocarpus as a model organism and discuss how the genomic information, genetic tools and molecular approaches available for this organism are being employed to explore developmental questions in an evolutionary context.
Collapse
Affiliation(s)
- Susana M. Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France
| | | | - Dieter Müller
- Fachbereich Biologie der Universitat Konstanz, 78457 Konstanz, Germany
| | - J. Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France
| |
Collapse
|
20
|
Dittami SM, Corre E, Brillet-Guéguen L, Lipinska AP, Pontoizeau N, Aite M, Avia K, Caron C, Cho CH, Collén J, Cormier A, Delage L, Doubleau S, Frioux C, Gobet A, González-Navarrete I, Groisillier A, Hervé C, Jollivet D, KleinJan H, Leblanc C, Liu X, Marie D, Markov GV, Minoche AE, Monsoor M, Pericard P, Perrineau MM, Peters AF, Siegel A, Siméon A, Trottier C, Yoon HS, Himmelbauer H, Boyen C, Tonon T. The genome of Ectocarpus subulatus - A highly stress-tolerant brown alga. Mar Genomics 2020; 52:100740. [PMID: 31937506 DOI: 10.1016/j.margen.2020.100740] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/01/2020] [Indexed: 11/20/2022]
Abstract
Brown algae are multicellular photosynthetic stramenopiles that colonize marine rocky shores worldwide. Ectocarpus sp. Ec32 has been established as a genomic model for brown algae. Here we present the genome and metabolic network of the closely related species, Ectocarpus subulatus Kützing, which is characterized by high abiotic stress tolerance. Since their separation, both strains show new traces of viral sequences and the activity of large retrotransposons, which may also be related to the expansion of a family of chlorophyll-binding proteins. Further features suspected to contribute to stress tolerance include an expanded family of heat shock proteins, the reduction of genes involved in the production of halogenated defence compounds, and the presence of fewer cell wall polysaccharide-modifying enzymes. Overall, E. subulatus has mainly lost members of gene families down-regulated in low salinities, and conserved those that were up-regulated in the same condition. However, 96% of genes that differed between the two examined Ectocarpus species, as well as all genes under positive selection, were found to encode proteins of unknown function. This underlines the uniqueness of brown algal stress tolerance mechanisms as well as the significance of establishing E. subulatus as a comparative model for future functional studies.
Collapse
Affiliation(s)
- Simon M Dittami
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France.
| | - Erwan Corre
- CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Loraine Brillet-Guéguen
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France; CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Agnieszka P Lipinska
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Noé Pontoizeau
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France; CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Meziane Aite
- Univ Rennes, Inria, CNRS, IRISA, 35000 Rennes, France
| | - Komlan Avia
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France; Université de Strasbourg, INRA, SVQV UMR-A 1131, F-68000 Colmar, France
| | - Christophe Caron
- CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Chung Hyun Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jonas Collén
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Alexandre Cormier
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Ludovic Delage
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Sylvie Doubleau
- IRD, UMR DIADE, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France
| | | | - Angélique Gobet
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Irene González-Navarrete
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Agnès Groisillier
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Cécile Hervé
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Didier Jollivet
- Sorbonne Université, CNRS, Adaptation and Diversity in the Marine Environment (ADME), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Hetty KleinJan
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Catherine Leblanc
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Xi Liu
- CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Dominique Marie
- Sorbonne Université, CNRS, Adaptation and Diversity in the Marine Environment (ADME), Station Biologique de Roscoff (SBR), 29680 Roscoff, France
| | - Gabriel V Markov
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - André E Minoche
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Misharl Monsoor
- CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Pierre Pericard
- CNRS, Sorbonne Université, FR2424, ABiMS platform, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Marie-Mathilde Perrineau
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France; Scottish Association for Marine Science, Scottish Marine Institute, Oban PA37 1QA, United Kingdom
| | | | - Anne Siegel
- Univ Rennes, Inria, CNRS, IRISA, 35000 Rennes, France
| | - Amandine Siméon
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Camille Trottier
- Univ Rennes, Inria, CNRS, IRISA, 35000 Rennes, France; Laboratory of Digital Sciences of Nantes (LS2N) - University of Nantes, France
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Heinz Himmelbauer
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, 1190 Vienna, Austria
| | - Catherine Boyen
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France
| | - Thierry Tonon
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680 Roscoff, France; Centre for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
| |
Collapse
|
21
|
Horinouchi Y, Yamaguchi M, Chibana H, Togashi T. Nuclear behavior and roles indicate that Codiolum phase is a sporophyte in Monostroma angicava (Ulotrichales, Ulvophyceae). JOURNAL OF PHYCOLOGY 2019; 55:534-542. [PMID: 30715731 DOI: 10.1111/jpy.12841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
The life-cycle system of Ulotrichales, a major order of Ulvophyceae, remains controversial because it is unclear whether the Codiolum phase, a characteristic unicellular diploid generation in ulotrichalean algae, is a zygote or a sporophyte. This controversy inhibits the understanding of the diversified life cycles in Ulvophyceae. To distinguish between zygotes and sporophytes, we have to examine not only whether diploid generations function as sporophytes, but also whether mitosis occurs before meiosis in diploid generations. However, the nuclear behavior in the Codiolum phases is largely unknown, probably because no suitable methods are available. Using fluorescent microscopy with ethidium bromide and transmission electron microscopy of cell-wall-dissected specimens, we report the nuclear behavior in the Codiolum phases of an ulotrichalean alga with a representative life cycle, Monostroma angicava. Each vegetative Codiolum phase had a single polyploid nucleus due to endoreduplication, a type of mitosis without nuclear division. During zoosporogenesis, the nucleus had a structure that would be a meiosis-specific complex. We quantitatively showed that Codiolum phases grew extremely large and produced numerous zoospores. Our results suggest that an event comparable to mitosis occurs before meiosis in the Codiolum phase of M. angicava. This nuclear behavior and the functions (growth and zoospore production abilities) correspond to those of sporophytes. Therefore, the life-cycle system of M. angicava is a heteromorphic haplo-diplontic cycle. This system appears to be widely adopted among other ulotrichalean algae.
Collapse
Affiliation(s)
- Yusuke Horinouchi
- Marine Biosystems Research Center, Chiba University, Kamogawa, 299-5502, Japan
| | - Masashi Yamaguchi
- Medical Mycology Research Center, Chiba University, Chiba, 260-8673, Japan
| | - Hiroji Chibana
- Medical Mycology Research Center, Chiba University, Chiba, 260-8673, Japan
| | - Tatsuya Togashi
- Marine Biosystems Research Center, Chiba University, Kamogawa, 299-5502, Japan
| |
Collapse
|
22
|
Mignerot L, Avia K, Luthringer R, Lipinska AP, Peters AF, Cock JM, Coelho SM. A key role for sex chromosomes in the regulation of parthenogenesis in the brown alga Ectocarpus. PLoS Genet 2019; 15:e1008211. [PMID: 31194744 PMCID: PMC6592573 DOI: 10.1371/journal.pgen.1008211] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 06/25/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023] Open
Abstract
Although evolutionary transitions from sexual to asexual reproduction are frequent in eukaryotes, the genetic bases of these shifts remain largely elusive. Here, we used classic quantitative trait analysis, combined with genomic and transcriptomic information to dissect the genetic basis of asexual, parthenogenetic reproduction in the brown alga Ectocarpus. We found that parthenogenesis is controlled by the sex locus, together with two additional autosomal loci, highlighting the key role of the sex chromosome as a major regulator of asexual reproduction. We identify several negative effects of parthenogenesis on male fitness, and different fitness effects of parthenogenetic capacity depending on the life cycle generation. Although allele frequencies in natural populations are currently unknown, we discuss the possibility that parthenogenesis may be under both sex-specific selection and generation/ploidally-antagonistic selection, and/or that the action of fluctuating selection on this trait may contribute to the maintenance of polymorphisms in populations. Importantly, our data provide the first empirical illustration, to our knowledge, of a trade-off between the haploid and diploid stages of the life cycle, where distinct parthenogenesis alleles have opposing effects on sexual and asexual reproduction and may help maintain genetic variation. These types of fitness trade-offs have profound evolutionary implications in natural populations and may structure life history evolution in organisms with haploid-diploid life cycles.
Collapse
Affiliation(s)
- Laure Mignerot
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Komlan Avia
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Remy Luthringer
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Agnieszka P. Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | | | - J. Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| | - Susana M. Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Roscoff, France
| |
Collapse
|
23
|
Kamiya M, Saba E, West JA. Marginal distribution and high heterozygosity of asexual Caloglossa vieillardii (Delesseriaceae, Rhodophyta) along the Australian coasts. JOURNAL OF PHYCOLOGY 2017; 53:1283-1293. [PMID: 28833125 DOI: 10.1111/jpy.12580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
In animals and land plants, many asexual species originate through inter- or intraspecific crosses, and such heterozygous asexuals frequently are more abundant than their sexual relatives in marginal habitats. Although asexual species have been reported in various macroalgal taxa, detailed information regarding their distribution, heterozygosity, and origin is limited. Because many asexual tetrasporophyte strains of Caloglossa vieillardii have been isolated from South Australia, far from their core tropical habitats, we re-examined the distribution range of asexual C. vieillardii and genotyped these and other western Pacific strains using an actin gene marker. We confirmed the marginal distribution of the asexuals; however, a small patch of sexual thalli was newly discovered 450 km further west from asexual populations in South Australia. Three heterozygous genotypes and one homozygous genotypes were detected from nine asexual populations; 21 heterozygous strains were obligately asexual, but one homozygous strain suddenly produced sexual gametophytes after several years of culture. We hypothesized that the most abundant heterozygous genotype (defined as type 3/4) in asexual populations occurred by a cross between type 3 and type 4 allele gametophytes, both of which were isolated from the Australian coasts. In the crossing experiments, certain combinations between type 3 females and type 4 males produced tetrasporophytes, which recycled successive tetrasporophytes. In the culture experiments, whereas both sexual and asexual strains successfully produced tetraspores at 12°C, no sexual strains released carpospores below 14°C. However, it is uncertain whether this slight difference of maturation temperature was related to the marginal distribution of asexual C. vieillardii.
Collapse
Affiliation(s)
- Mitsunobu Kamiya
- Faculty of Marine Bioscience, Fukui Prefectural University, 1-1, Gakuen-cho, Obama, Fukui, 917-0003, Japan
| | - Erika Saba
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 1-1, Gakuen-cho, Obama, Fukui, 917-0003, Japan
| | - John A West
- School of Biosciences 2, University of Melbourne, Parkville, Victoria, 3010, Australia
| |
Collapse
|
24
|
Müller DG, Maier I, Marie D, Westermeier R. Nuclear DNA level and life cycle of kelps: Evidence for sex-specific polyteny in Macrocystis (Laminariales, Phaeophyceae). JOURNAL OF PHYCOLOGY 2016; 52:157-60. [PMID: 27037581 DOI: 10.1111/jpy.12380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Giant kelp, Macrocystis pyrifera (Linnaeus) C. Agardh, is the subject of intense breeding studies for marine biomass production and conservation of natural resources. In this context, six gametophyte pairs and a sporophyte offspring of Macrocystis from South America were analyzed by flow cytometry. Minimum relative DNA content per cell (1C) was found in five males. Unexpectedly, nuclei of all female gametophytes contained approximately double the DNA content (2C) of males; the male gametophyte from one locality also contained 2C, likely a spontaneous natural diploid variant. The results illustrate a sex-specific difference in nuclear DNA content among Macrocystis gametophytes, with the chromosomes of the females in a polytenic condition. This correlates with significantly larger cell sizes in female gametophytes compared to males and resource allocation in oogamous reproduction. The results provide key information for the interpretation of DNA measurements in kelp life cycle stages and prompt further research on the regulation of the cell cycle, metabolic activity, sex determination, and sporophyte development.
Collapse
Affiliation(s)
- Dieter G Müller
- Fakultät für Biologie der Universität Konstanz, Konstanz, D-78464, Germany
| | - Ingo Maier
- MABIOLA, Hochgratweg 12, Amtzell, D-88279, Germany
| | - Dominique Marie
- Station Biologique de Roscoff, Roscoff, Cedex, 29682, France
| | - Renato Westermeier
- Universidad Austral de Chile, Sede Puerto Montt, PO Box 1327, Puerto Montt, Chile
| |
Collapse
|
25
|
Couceiro L, Le Gac M, Hunsperger HM, Mauger S, Destombe C, Cock JM, Ahmed S, Coelho SM, Valero M, Peters AF. Evolution and maintenance of haploid-diploid life cycles in natural populations: The case of the marine brown alga Ectocarpus. Evolution 2015; 69:1808-22. [PMID: 26096000 DOI: 10.1111/evo.12702] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 05/13/2015] [Accepted: 05/26/2015] [Indexed: 11/26/2022]
Abstract
The evolutionary stability of haploid-diploid life cycles is still controversial. Mathematical models indicate that niche differences between ploidy phases may be a necessary condition for the evolution and maintenance of these life cycles. Nevertheless, experimental support for this prediction remains elusive. In the present work, we explored this hypothesis in natural populations of the brown alga Ectocarpus. Consistent with the life cycle described in culture, Ectocarpus crouaniorum in NW France and E. siliculosus in SW Italy exhibited an alternation between haploid gametophytes and diploid sporophytes. Our field data invalidated, however, the long-standing view of an isomorphic alternation of generations. Gametophytes and sporophytes displayed marked differences in size and, conforming to theoretical predictions, occupied different spatiotemporal niches. Gametophytes were found almost exclusively on the alga Scytosiphon lomentaria during spring whereas sporophytes were present year-round on abiotic substrata. Paradoxically, E. siliculosus in NW France exhibited similar habitat usage despite the absence of alternation of ploidy phases. Diploid sporophytes grew both epilithically and epiphytically, and this mainly asexual population gained the same ecological advantage postulated for haploid-diploid populations. Consequently, an ecological interpretation of the niche differences between haploid and diploid individuals does not seem to satisfactorily explain the evolution of the Ectocarpus life cycle.
Collapse
Affiliation(s)
- Lucía Couceiro
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France.
| | - Mickael Le Gac
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France
- Current Address: Ifremer, DYNECO PELAGOS, 29280, Plouzané, France
| | - Heather M Hunsperger
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France
- Current Address: Department of Biology, University of Washington, Seattle, Washington, 98195
| | - Stéphane Mauger
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France
| | - Christophe Destombe
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France
| | - J Mark Cock
- CNRS, Sorbonne Universités, UPMC, UMR 7139, Algal Genetics, Station Biologique de Roscoff, Place G, Tessier, 29688, Roscoff, France
| | - Sophia Ahmed
- CNRS, Sorbonne Universités, UPMC, UMR 7139, Algal Genetics, Station Biologique de Roscoff, Place G, Tessier, 29688, Roscoff, France
- Current Address: Department for Plant Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Susana M Coelho
- CNRS, Sorbonne Universités, UPMC, UMR 7139, Algal Genetics, Station Biologique de Roscoff, Place G, Tessier, 29688, Roscoff, France
| | - Myriam Valero
- CNRS, Sorbonne Universités, UPMC, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, PUCCh, UACH, CS 90074, Place G, Tessier, 29688, Roscoff, France
| | | |
Collapse
|
26
|
Emergence of Ectocarpus as a Model System to Study the Evolution of Complex Multicellularity in the Brown Algae. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-94-017-9642-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
|
27
|
Huysman MJJ, Tanaka A, Bowler C, Vyverman W, De Veylder L. Functional characterization of the diatom cyclin-dependent kinase A2 as a mitotic regulator reveals plant-like properties in a non-green lineage. BMC PLANT BIOLOGY 2015; 15:86. [PMID: 25887918 PMCID: PMC4392632 DOI: 10.1186/s12870-015-0469-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 02/26/2015] [Indexed: 06/01/2023]
Abstract
BACKGROUND Cyclin-dependent kinases (CDKs) are crucial regulators of cell cycle progression in eukaryotes. The diatom CDKA2 was originally assigned to the classical A-type CDKs, but its cell cycle phase-specific transcription at the G2-to-M phase transition is typical for plant-specific B-type CDKs. RESULTS Here, we report the functional characterization of CDKA2 from the diatom Phaeodactylum tricornutum. Through a yeast two-hybrid library screen, CDKA2 was found to interact with the G2/M-specific CDK scaffolding factor CKS1. Localization of CDKA2 was found to be nuclear in interphase cells, while in cells undergoing cytokinesis, the signal extended to the cell division plane. In addition, overexpression of CDKA2 induced an overall reduction in the cell growth rate. Expression analysis of cell cycle marker genes in the overexpression lines indicates that this growth reduction is primarily due to a prolongation of the mitotic phase. CONCLUSIONS Our study indicates a role for CDKA2 during cell division in diatoms. The functional characterization of a CDK with clear CDKB properties in a non-green organism questions whether the current definition of B-type CDKs being plant-specific might need revision.
Collapse
Affiliation(s)
- Marie J J Huysman
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), 9052, Ghent, Belgium.
- Department of Plant Systems Biology, VIB, and Bioinformatics, Ghent University, 9052, Ghent, Belgium.
- Protistology and Aquatic Ecology, Department of Biology, Ghent University, 9000, Ghent, Belgium.
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
| | - Atsuko Tanaka
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
- Current address: Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, Hokkaido, 051-0013, Japan.
| | - Chris Bowler
- Environmental and Evolutionary Genomics Section, Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8186, Institut National de la Santé et de la Recherche Médicale U1024, Ecole Normale Supérieure, 75230, Paris, Cedex 05, France.
| | - Wim Vyverman
- Protistology and Aquatic Ecology, Department of Biology, Ghent University, 9000, Ghent, Belgium.
| | - Lieven De Veylder
- Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), 9052, Ghent, Belgium.
- Department of Plant Systems Biology, VIB, and Bioinformatics, Ghent University, 9052, Ghent, Belgium.
| |
Collapse
|
28
|
Oppliger LV, von Dassow P, Bouchemousse S, Robuchon M, Valero M, Correa JA, Mauger S, Destombe C. Alteration of sexual reproduction and genetic diversity in the kelp species Laminaria digitata at the southern limit of its range. PLoS One 2014; 9:e102518. [PMID: 25019953 PMCID: PMC4096927 DOI: 10.1371/journal.pone.0102518] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 06/19/2014] [Indexed: 12/04/2022] Open
Abstract
Adaptation to marginal habitats at species range-limits has often been associated with parthenogenetic reproduction in terrestrial animals and plants. Laboratory observations have shown that brown algae exhibit a high propensity for parthenogenesis by various mechanisms. The kelp Laminaria digitata is an important component of the ecosystem in Northern European rocky intertidal habitats. We studied four L. digitata populations for the effects of marginality on genetic diversity and sexual reproduction. Two populations were marginal: One (Locquirec, in Northern Brittany) was well within the geographic range, but was genetically isolated from other populations by large stretches of sandy beaches. Another population was at the range limits of the species (Quiberon, in Southern Brittany) and was exposed to much higher seasonal temperature changes. Microsatellite analyses confirmed that these populations showed decreased genetic and allelic diversity, consistent with marginality and genetic isolation. Sporophytes from both marginal populations showed greatly diminished spore-production compared to central populations, but only the southern-limit population (Quiberon) showed a high propensity for producing unreduced (2N) spores. Unreduced 2N spores formed phenotypically normal gametophytes with nuclear area consistent with ≥2N DNA contents, and microsatellite studies suggested these were produced at least in part by automixis. However, despite this being the dominant path of spore production in Quiberon sporophyte individuals, the genetic evidence indicated the population was maintained mostly by sexual reproduction. Thus, although spore production and development showed the expected tendency of geographical parthenogenesis in marginal populations, this appeared to be a consequence of maladaptation, rather than an adaptation to, life in a marginal habitat.
Collapse
Affiliation(s)
- Luz Valeria Oppliger
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
- Center of Applied Ecology & Sustainability, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Peter von Dassow
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Instituto Milenio de Oceanografía (IMO), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sarah Bouchemousse
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| | - Marine Robuchon
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
- Institut de Systématique, Evolution, Biodiversité, UMR 7205, Muséum national d’Histoire naturelle, Paris, France
| | - Myriam Valero
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| | - Juan A. Correa
- Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Center of Applied Ecology & Sustainability, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Stéphane Mauger
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| | - Christophe Destombe
- Sorbonne Universités, UPMC Univ. Paris 06, UMR 7144, Station Biologique de Roscoff, Roscoff, France
- CNRS, UMR 7144, Station Biologique de Roscoff, Place Georges Teissier, Roscoff, France
| |
Collapse
|
29
|
Abstract
Brown algae are an extremely interesting, but surprisingly poorly explored, group of organisms. They are one of only five eukaryotic lineages to have independently evolved complex multicellularity, which they express through a wide variety of morphologies ranging from uniseriate branched filaments to complex parenchymatous thalli with multiple cell types. Despite their very distinct evolutionary history, brown algae and land plants share a striking amount of developmental features. This has led to an interest in several aspects of brown algal development, including embryogenesis, polarity, cell cycle, asymmetric cell division and a putative role for plant hormone signalling. This review describes how investigations using brown algal models have helped to increase our understanding of the processes controlling early embryo development, in particular polarization, axis formation and asymmetric cell division. Additionally, the diversity of life cycles in the brown lineage and the emergence of Ectocarpus as a powerful model organism, are affording interesting insights on the molecular mechanisms underlying haploid-diploid life cycles. The use of these and other emerging brown algal models will undoubtedly add to our knowledge on the mechanisms that regulate development in multicellular photosynthetic organisms.
Collapse
Affiliation(s)
- Kenny A Bogaert
- Phycology Research Group, Department of Biology, Center for Molecular Phylogenetics and Evolution, Ghent University, Ghent, Belgium
| | | | | | | |
Collapse
|
30
|
Arun A, Peters NT, Scornet D, Peters AF, Mark Cock J, Coelho SM. Non-cell autonomous regulation of life cycle transitions in the model brown alga Ectocarpus. THE NEW PHYTOLOGIST 2013; 197:503-510. [PMID: 23106314 DOI: 10.1111/nph.12007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 09/24/2012] [Indexed: 05/29/2023]
Abstract
The model brown alga Ectocarpus has a haploid-diploid life cycle, involving alternation between two independent multicellular generations, the gametophyte and the sporophyte. Recent work has shown that alternation of generations is not determined by ploidy but is rather under genetic control, involving at least one master regulatory locus, OUROBOROS (ORO). Using cell biology approaches combined with measurements of generation-specific transcript abundance we provide evidence that alternation of generations can also be regulated by non-cell autonomous mechanisms. The Ectocarpus sporophyte produces a diffusible factor that causes major developmental reprogramming in gametophyte cells. Cells become resistant to reprogramming when the cell wall is synthetized, suggesting that the cell wall may play a role in locking an individual into the developmental program that has been engaged. A functional ORO gene is necessary for the induction of the developmental switch. Our results highlight the role of the cell wall in maintaining the differentiated generation stage once the appropriate developmental program has been engaged and also indicate that ORO is a key member of the developmental pathway triggered by the sporophyte factor. Alternation between gametophyte and sporophyte generations in Ectocarpus is surprisingly labile, perhaps reflecting an adaptation to the variable seashore environment inhabited by this alga.
Collapse
Affiliation(s)
- Alok Arun
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
- The Marine Plants and Biomolecules Laboratory, UMR 7139, UPMC Université Paris 06, Station Biologique de Roscoff, BP74, 29682, Roscoff Cedex, France
| | - Nick T Peters
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
- The Marine Plants and Biomolecules Laboratory, UMR 7139, UPMC Université Paris 06, Station Biologique de Roscoff, BP74, 29682, Roscoff Cedex, France
- Department of Biology, University of Utah, Salt Lake City, Utah, USA
| | - Delphine Scornet
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
| | - Akira F Peters
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
- The Marine Plants and Biomolecules Laboratory, UMR 7139, UPMC Université Paris 06, Station Biologique de Roscoff, BP74, 29682, Roscoff Cedex, France
- Bezhin Rosko, 29250, Santec, France
| | - J Mark Cock
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
- The Marine Plants and Biomolecules Laboratory, UMR 7139, UPMC Université Paris 06, Station Biologique de Roscoff, BP74, 29682, Roscoff Cedex, France
| | - Susana M Coelho
- UMR 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, CNRS, Place Georges Teissier, BP74, 29682, Roscoff Cedex, France
- The Marine Plants and Biomolecules Laboratory, UMR 7139, UPMC Université Paris 06, Station Biologique de Roscoff, BP74, 29682, Roscoff Cedex, France
| |
Collapse
|
31
|
Coelho SM, Scornet D, Rousvoal S, Peters NT, Dartevelle L, Peters AF, Cock JM. Ectocarpus: a model organism for the brown algae. Cold Spring Harb Protoc 2012; 2012:193-8. [PMID: 22301644 DOI: 10.1101/pdb.emo065821] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The brown algae are an interesting group of organisms from several points of view. They are the dominant organisms in many coastal ecosystems, where they often form large, underwater forests. They also have an unusual evolutionary history, being members of the stramenopiles, which are very distantly related to well-studied animal and green plant models. As a consequence of this history, brown algae have evolved many novel features, for example in terms of their cell biology and metabolic pathways. They are also one of only a small number of eukaryotic groups to have independently evolved complex multicellularity. Despite these interesting features, the brown algae have remained a relatively poorly studied group. This situation has started to change over the last few years, however, with the emergence of the filamentous brown alga Ectocarpus as a model system that is amenable to the genomic and genetic approaches that have proved to be so powerful in more classical model organisms such as Drosophila and Arabidopsis.
Collapse
Affiliation(s)
- Susana M Coelho
- UPMC Université Paris 06, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, BP74, 29682 Roscoff Cedex, France
| | | | | | | | | | | | | |
Collapse
|
32
|
Cock JM, Arun A, Godfroy O, Macaisne N, Strittmatter M, Peters AF, Coelho SM. Genomics of brown algae: current advances and future prospects. Genes Genomics 2012. [DOI: 10.1007/s13258-010-0225-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
33
|
Coelho SM, Godfroy O, Arun A, Le Corguillé G, Peters AF, Cock JM. Genetic regulation of life cycle transitions in the brown alga Ectocarpus. PLANT SIGNALING & BEHAVIOR 2011; 6:1858-60. [PMID: 22067105 PMCID: PMC3329369 DOI: 10.4161/psb.6.11.17737] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The life cycle of an organism is one of its most elemental features, underpinning a broad range of phenomena including developmental processes, reproductive fitness, mode of dispersal and adaptation to the local environment. Life cycle modification may have played an important role during the evolution of several eukaryotic groups, including the terrestrial plants. Brown algae are potentially interesting models to study life cycle evolution because this group exhibits a broad range of different life cycles. Currently, life cycle studies are focused on the emerging brown algal model Ectocarpus. Two life cycle mutants have been described in this species, both of which cause the sporophyte generation to exhibit gametophyte characteristics. The ouroboros mutation is particularly interesting because it induces complete conversion of the sporophyte generation into a functional, gamete-producing gametophyte, a class of mutation that has not been described so far in other systems. Analysis of Ectocarpus life cycle mutants is providing insights into several life-cycle-related processes including parthenogenesis, symmetric/asymmetric initial cell divisions and sex determination.
Collapse
Affiliation(s)
- Susana M. Coelho
- CNRS, Station Biologique de Roscoff; Roscoff, France
- Université Pierre et Marie Curie; Paris France
| | - Olivier Godfroy
- CNRS, Station Biologique de Roscoff; Roscoff, France
- Université Pierre et Marie Curie; Paris France
| | - Alok Arun
- CNRS, Station Biologique de Roscoff; Roscoff, France
- Université Pierre et Marie Curie; Paris France
| | - Gildas Le Corguillé
- Service Informatique et Génomique, Station Biologique de Roscoff; Roscoff, France
| | | | - J. Mark Cock
- CNRS, Station Biologique de Roscoff; Roscoff, France
- Université Pierre et Marie Curie; Paris France
| |
Collapse
|
34
|
Coelho SM, Godfroy O, Arun A, Le Corguillé G, Peters AF, Cock JM. OUROBOROS is a master regulator of the gametophyte to sporophyte life cycle transition in the brown alga Ectocarpus. Proc Natl Acad Sci U S A 2011; 108:11518-23. [PMID: 21709217 PMCID: PMC3136289 DOI: 10.1073/pnas.1102274108] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The brown alga Ectocarpus siliculosus has a haploid-diploid life cycle that involves an alternation between two distinct generations, the sporophyte and the gametophyte. We describe a mutant, ouroboros (oro), in which the sporophyte generation is converted into a functional, gamete-producing gametophyte. The life history of the mutant thus consists of a continuous reiteration of the gametophyte generation. The oro mutant exhibited morphological features typical of the gametophyte generation and accumulated transcripts of gametophyte generation marker genes. Genetic analysis showed that oro behaved as a single, recessive, Mendelian locus that was unlinked to the IMMEDIATE UPRIGHT locus, which has been shown to be necessary for full expression of the sporophyte developmental program. The data presented here indicate that ORO is a master regulator of the gametophyte-to-sporophyte life cycle transition and, moreover, that oro represents a unique class of homeotic mutation that results in switching between two developmental programs that operate at the level of the whole organism.
Collapse
Affiliation(s)
- Susana M. Coelho
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
- Université Pierre et Marie Curie, Université Paris 6, Marine Plants and Biomolecules Laboratory, Unité Mixte de Recherche 7139, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
| | - Olivier Godfroy
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
- Université Pierre et Marie Curie, Université Paris 6, Marine Plants and Biomolecules Laboratory, Unité Mixte de Recherche 7139, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
| | - Alok Arun
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
- Université Pierre et Marie Curie, Université Paris 6, Marine Plants and Biomolecules Laboratory, Unité Mixte de Recherche 7139, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
| | - Gildas Le Corguillé
- Service Informatique et Génomique, Station Biologique de Roscoff, 29682 Roscoff Cedex, France; and
| | | | - J. Mark Cock
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7139, Laboratoire International Associé Dispersal and Adaptation in Marine Species, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
- Université Pierre et Marie Curie, Université Paris 6, Marine Plants and Biomolecules Laboratory, Unité Mixte de Recherche 7139, Station Biologique de Roscoff, 29682 Roscoff Cedex, France
| |
Collapse
|
35
|
Bothwell JH, Marie D, Peters AF, Cock JM, Coelho SM. Cell cycles and endocycles in the model brown seaweed, Ectocarpus siliculosus. PLANT SIGNALING & BEHAVIOR 2010; 5:1473-5. [PMID: 21057192 PMCID: PMC3115259 DOI: 10.4161/psb.5.11.13520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 09/03/2010] [Indexed: 05/30/2023]
Abstract
The recent announcement of the first genome sequence of a brown macroalga, the filamentous Ectocarpus, has been accompanied by a number of companion papers in New Phytologist. In a paper which contributes to this special issue, we classified the core cell cycle components of Ectocarpus, comparing them to the previously studied cell cycle components of diatoms. We then carried out fluorescence microscopy experiments to show that the Ectocarpus cell cycle could be deregulated during early development to give endopolyploid adults. We discuss here how our findings complement recent studies on endopolyploidy in plant and algal systems.
Collapse
Affiliation(s)
- John H Bothwell
- Queen's University Belfast, School of Biological Sciences, Belfast, UK
| | | | | | | | | |
Collapse
|
36
|
Cock JM, Coelho SM, Brownlee C, Taylor AR. The Ectocarpus genome sequence: insights into brown algal biology and the evolutionary diversity of the eukaryotes. THE NEW PHYTOLOGIST 2010; 188:1-4. [PMID: 20840144 DOI: 10.1111/j.1469-8137.2010.03454.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Affiliation(s)
- J Mark Cock
- UPMC Université Paris 06, The Marine Plants and Biomolecules Laboratory, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, 29682 Roscoff Cedex, France. email
| | | | | | | |
Collapse
|