1
|
Babonis LS. On the evolutionary developmental biology of the cell. Trends Genet 2024:S0168-9525(24)00150-1. [PMID: 38971670 DOI: 10.1016/j.tig.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 07/08/2024]
Abstract
Organisms are complex assemblages of cells, cells that produce light, shoot harpoons, and secrete glue. Therefore, identifying the mechanisms that generate novelty at the level of the individual cell is essential for understanding how multicellular life evolves. For decades, the field of evolutionary developmental biology (Evo-Devo) has been developing a framework for connecting genetic variation that arises during embryonic development to the emergence of diverse adult forms. With increasing access to new single cell 'omics technologies and an array of techniques for manipulating gene expression, we can now extend these inquiries inward to the level of the individual cell. In this opinion, I argue that applying an Evo-Devo framework to single cells makes it possible to explore the natural history of cells, where this was once only possible at the organismal level.
Collapse
Affiliation(s)
- Leslie S Babonis
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
2
|
Taylor WA, Strother PK. Plant evolution: A tapetum is now effectively present in all land plant lineages. Curr Biol 2024; 34:R146-R148. [PMID: 38412824 DOI: 10.1016/j.cub.2023.12.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
The tapetum, a tissue that elsewhere ensures correct spore development, is missing in some bryophytes. A new study shows that, in the liverwort, Marchantia polymorpha, a gene controlling spore wall deposition is expressed in the capsule lining, so these cells essentially function as a tapetum.
Collapse
Affiliation(s)
- Wilson A Taylor
- Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI, USA
| | - Paul K Strother
- Department of Earth and Environmental Sciences, Boston College Weston Observatory, Weston, MA, USA.
| |
Collapse
|
3
|
McCourt RM, Lewis LA, Strother PK, Delwiche CF, Wickett NJ, de Vries J, Bowman JL. Green land: Multiple perspectives on green algal evolution and the earliest land plants. AMERICAN JOURNAL OF BOTANY 2023; 110:e16175. [PMID: 37247371 DOI: 10.1002/ajb2.16175] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Revised: 03/10/2023] [Accepted: 03/10/2023] [Indexed: 05/31/2023]
Abstract
Green plants, broadly defined as green algae and the land plants (together, Viridiplantae), constitute the primary eukaryotic lineage that successfully colonized Earth's emergent landscape. Members of various clades of green plants have independently made the transition from fully aquatic to subaerial habitats many times throughout Earth's history. The transition, from unicells or simple filaments to complex multicellular plant bodies with functionally differentiated tissues and organs, was accompanied by innovations built upon a genetic and phenotypic toolkit that have served aquatic green phototrophs successfully for at least a billion years. These innovations opened an enormous array of new, drier places to live on the planet and resulted in a huge diversity of land plants that have dominated terrestrial ecosystems over the past 500 million years. This review examines the greening of the land from several perspectives, from paleontology to phylogenomics, to water stress responses and the genetic toolkit shared by green algae and plants, to the genomic evolution of the sporophyte generation. We summarize advances on disparate fronts in elucidating this important event in the evolution of the biosphere and the lacunae in our understanding of it. We present the process not as a step-by-step advancement from primitive green cells to an inevitable success of embryophytes, but rather as a process of adaptations and exaptations that allowed multiple clades of green plants, with various combinations of morphological and physiological terrestrialized traits, to become diverse and successful inhabitants of the land habitats of Earth.
Collapse
Affiliation(s)
- Richard M McCourt
- Department of Biodiversity, Earth, and Environmental Sciences, Drexel University, Philadelphia, PA, 19118, USA
| | - Louise A Lewis
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, 06269, USA
| | - Paul K Strother
- Department of Earth and Environmental Sciences, Boston College Weston Observatory, 381 Concord Road, Weston, MA, 02493, USA
| | - Charles F Delwiche
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Norman J Wickett
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC, 29634, USA
| | - Jan de Vries
- Göttingen Center for Molecular Biosciences, Department of Applied Bioinformatics, University of Göttingen Goldschmidtstr. 1, Göttingen, 37077, Germany
| | - John L Bowman
- School of Biological Sciences, Monash University, Clayton Campus, Melbourne, Victoria, 3800, Australia
| |
Collapse
|
4
|
Bowman JL. The origin of a land flora. NATURE PLANTS 2022; 8:1352-1369. [PMID: 36550365 DOI: 10.1038/s41477-022-01283-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 10/19/2022] [Indexed: 05/12/2023]
Abstract
The origin of a land flora fundamentally shifted the course of evolution of life on earth, facilitating terrestrialization of other eukaryotic lineages and altering the planet's geology, from changing atmospheric and hydrological cycles to transforming continental erosion processes. Despite algal lineages inhabiting the terrestrial environment for a considerable preceding period, they failed to evolve complex multicellularity necessary to conquer the land. About 470 million years ago, one lineage of charophycean alga evolved complex multicellularity via developmental innovations in both haploid and diploid generations and became land plants (embryophytes), which rapidly diversified to dominate most terrestrial habitats. Genome sequences have provided unprecedented insights into the genetic and genomic bases for embryophyte origins, with some embryophyte-specific genes being associated with the evolution of key developmental or physiological attributes, such as meristems, rhizoids and the ability to form mycorrhizal associations. However, based on the fossil record, the evolution of the defining feature of embryophytes, the embryo, and consequently the sporangium that provided a reproductive advantage, may have been most critical in their rise to dominance. The long timeframe and singularity of a land flora were perhaps due to the stepwise assembly of a large constellation of genetic innovations required to conquer the terrestrial environment.
Collapse
Affiliation(s)
- John L Bowman
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia.
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, Monash University, Melbourne, Victoria, Australia.
| |
Collapse
|
5
|
Levins J, Dierschke T, Bowman JL. The nature of nurture: the conserved role of tapetal-like cells in sporogenesis between mosses and angiosperms. THE NEW PHYTOLOGIST 2022; 235:377-379. [PMID: 35445752 DOI: 10.1111/nph.18142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Affiliation(s)
- Jonathan Levins
- School of Biological Sciences, Monash University, Clayton, Melbourne, Vic., 3800, Australia
| | - Tom Dierschke
- School of Biological Sciences, Monash University, Clayton, Melbourne, Vic., 3800, Australia
| | - John L Bowman
- School of Biological Sciences, Monash University, Clayton, Melbourne, Vic., 3800, Australia
- ARC Centre of Excellence for Plant Success in Nature and Agriculture, Monash University, Clayton, Melbourne, Vic., 3800, Australia
| |
Collapse
|
6
|
Lopez‐Obando M, Landberg K, Sundberg E, Thelander M. Dependence on clade II bHLH transcription factors for nursing of haploid products by tapetal-like cells is conserved between moss sporangia and angiosperm anthers. THE NEW PHYTOLOGIST 2022; 235:718-731. [PMID: 35037245 PMCID: PMC9306660 DOI: 10.1111/nph.17972] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/28/2021] [Indexed: 05/16/2023]
Abstract
Clade II basic helix-loop-helix transcription factors (bHLH TFs) are essential for pollen production and tapetal nursing functions in angiosperm anthers. As pollen has been suggested to be related to bryophyte spores by descent, we characterized two Physcomitrium (Physcomitrella) patens clade II bHLH TFs (PpbHLH092 and PpbHLH098), to test if regulation of sporogenous cells and the nursing cells surrounding them is conserved between angiosperm anthers and bryophyte sporangia. We made CRISPR-Cas9 reporter and loss-of-function lines to address the function of PpbHLH092/098. We sectioned and analyzed WT and mutant sporophytes for a comprehensive stage-by-stage comparison of sporangium development. Spore precursors in the P. patens sporangium are surrounded by nursing cells showing striking similarities to tapetal cells in angiosperms. Moss clade II bHLH TFs are essential for the differentiation of these tapetal-like cells and for the production of functional spores. Clade II bHLH TFs provide a conserved role in controlling the sporophytic somatic cells surrounding and nursing the sporogenous cells in both moss sporangia and angiosperm anthers. This supports the hypothesis that such nursing functions in mosses and angiosperms, lineages separated by c. 450 million years, are related by descent.
Collapse
Affiliation(s)
- Mauricio Lopez‐Obando
- Department of Plant BiologyThe Linnean Centre of Plant Biology in UppsalaSwedish University of Agricultural SciencesPO Box 7080UppsalaSE‐75007Sweden
- VEDAS Corporación de Investigación e Innovación (VEDASCII)Cl 8 B 65‐261 050024MedellínColombia
| | - Katarina Landberg
- Department of Plant BiologyThe Linnean Centre of Plant Biology in UppsalaSwedish University of Agricultural SciencesPO Box 7080UppsalaSE‐75007Sweden
| | - Eva Sundberg
- Department of Plant BiologyThe Linnean Centre of Plant Biology in UppsalaSwedish University of Agricultural SciencesPO Box 7080UppsalaSE‐75007Sweden
| | - Mattias Thelander
- Department of Plant BiologyThe Linnean Centre of Plant Biology in UppsalaSwedish University of Agricultural SciencesPO Box 7080UppsalaSE‐75007Sweden
| |
Collapse
|
7
|
Grienenberger E, Quilichini TD. The Toughest Material in the Plant Kingdom: An Update on Sporopollenin. FRONTIERS IN PLANT SCIENCE 2021; 12:703864. [PMID: 34539697 PMCID: PMC8446667 DOI: 10.3389/fpls.2021.703864] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 05/16/2023]
Abstract
The extreme chemical and physical recalcitrance of sporopollenin deems this biopolymer among the most resilient organic materials on Earth. As the primary material fortifying spore and pollen cell walls, sporopollenin is touted as a critical innovation in the progression of plant life to a terrestrial setting. Although crucial for its protective role in plant reproduction, the inert nature of sporopollenin has challenged efforts to determine its composition for decades. Revised structural, chemical, and genetic experimentation efforts have produced dramatic advances in elucidating the molecular structure of this biopolymer and the mechanisms of its synthesis. Bypassing many of the challenges with material fragmentation and solubilization, insights from functional characterizations of sporopollenin biogenesis in planta, and in vitro, through a gene-targeted approach suggest a backbone of polyhydroxylated polyketide-based subunits and remarkable conservation of biochemical pathways for sporopollenin biosynthesis across the plant kingdom. Recent optimization of solid-state NMR and targeted degradation methods for sporopollenin analysis confirms polyhydroxylated α-pyrone subunits, as well as hydroxylated aliphatic units, and unique cross-linkage heterogeneity. We examine the cross-disciplinary efforts to solve the sporopollenin composition puzzle and illustrate a working model of sporopollenin's molecular structure and biosynthesis. Emerging controversies and remaining knowledge gaps are discussed, including the degree of aromaticity, cross-linkage profiles, and extent of chemical conservation of sporopollenin among land plants. The recent developments in sporopollenin research present diverse opportunities for harnessing the extraordinary properties of this abundant and stable biomaterial for sustainable microcapsule applications and synthetic material designs.
Collapse
Affiliation(s)
- Etienne Grienenberger
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Teagen D. Quilichini
- Aquatic and Crop Resource Development Research Centre, National Research Council Canada, Saskatoon, SK, Canada
| |
Collapse
|
8
|
Strother PK, Foster C. A fossil record of land plant origins from charophyte algae. Science 2021; 373:792-796. [PMID: 34385396 DOI: 10.1126/science.abj2927] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/17/2021] [Indexed: 11/02/2022]
Abstract
Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).
Collapse
Affiliation(s)
- Paul K Strother
- Weston Observatory, Department of Earth and Environmental Sciences, Boston College, Weston, MA 02493, USA.
| | - Clinton Foster
- Research School of Earth Sciences, The Australian National University, Canberra ACT 2601, Australia
| |
Collapse
|
9
|
Affiliation(s)
- Patricia G Gensel
- Biology Department, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
10
|
Julca I, Ferrari C, Flores-Tornero M, Proost S, Lindner AC, Hackenberg D, Steinbachová L, Michaelidis C, Gomes Pereira S, Misra CS, Kawashima T, Borg M, Berger F, Goldberg J, Johnson M, Honys D, Twell D, Sprunck S, Dresselhaus T, Becker JD, Mutwil M. Comparative transcriptomic analysis reveals conserved programmes underpinning organogenesis and reproduction in land plants. NATURE PLANTS 2021; 7:1143-1159. [PMID: 34253868 DOI: 10.1101/2020.10.29.361501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 06/02/2021] [Indexed: 05/19/2023]
Abstract
The appearance of plant organs mediated the explosive radiation of land plants, which shaped the biosphere and allowed the establishment of terrestrial animal life. The evolution of organs and immobile gametes required the coordinated acquisition of novel gene functions, the co-option of existing genes and the development of novel regulatory programmes. However, no large-scale analyses of genomic and transcriptomic data have been performed for land plants. To remedy this, we generated gene expression atlases for various organs and gametes of ten plant species comprising bryophytes, vascular plants, gymnosperms and flowering plants. A comparative analysis of the atlases identified hundreds of organ- and gamete-specific orthogroups and revealed that most of the specific transcriptomes are significantly conserved. Interestingly, our results suggest that co-option of existing genes is the main mechanism for evolving new organs. In contrast to female gametes, male gametes showed a high number and conservation of specific genes, which indicates that male reproduction is highly specialized. The expression atlas capturing pollen development revealed numerous transcription factors and kinases essential for pollen biogenesis and function.
Collapse
Affiliation(s)
- Irene Julca
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Camilla Ferrari
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany
| | - María Flores-Tornero
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sebastian Proost
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
- VIB, Center for Microbiology, Leuven, Belgium
| | | | - Dieter Hackenberg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
- School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry, UK
| | - Lenka Steinbachová
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | - Christos Michaelidis
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | | | - Chandra Shekhar Misra
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tomokazu Kawashima
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Michael Borg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
| | - Jacob Goldberg
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Mark Johnson
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
| | - Marek Mutwil
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| |
Collapse
|
11
|
Julca I, Ferrari C, Flores-Tornero M, Proost S, Lindner AC, Hackenberg D, Steinbachová L, Michaelidis C, Gomes Pereira S, Misra CS, Kawashima T, Borg M, Berger F, Goldberg J, Johnson M, Honys D, Twell D, Sprunck S, Dresselhaus T, Becker JD, Mutwil M. Comparative transcriptomic analysis reveals conserved programmes underpinning organogenesis and reproduction in land plants. NATURE PLANTS 2021; 7:1143-1159. [PMID: 34253868 DOI: 10.1038/s41477-021-00958-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 06/02/2021] [Indexed: 05/22/2023]
Abstract
The appearance of plant organs mediated the explosive radiation of land plants, which shaped the biosphere and allowed the establishment of terrestrial animal life. The evolution of organs and immobile gametes required the coordinated acquisition of novel gene functions, the co-option of existing genes and the development of novel regulatory programmes. However, no large-scale analyses of genomic and transcriptomic data have been performed for land plants. To remedy this, we generated gene expression atlases for various organs and gametes of ten plant species comprising bryophytes, vascular plants, gymnosperms and flowering plants. A comparative analysis of the atlases identified hundreds of organ- and gamete-specific orthogroups and revealed that most of the specific transcriptomes are significantly conserved. Interestingly, our results suggest that co-option of existing genes is the main mechanism for evolving new organs. In contrast to female gametes, male gametes showed a high number and conservation of specific genes, which indicates that male reproduction is highly specialized. The expression atlas capturing pollen development revealed numerous transcription factors and kinases essential for pollen biogenesis and function.
Collapse
Affiliation(s)
- Irene Julca
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Camilla Ferrari
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany
| | - María Flores-Tornero
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sebastian Proost
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, Germany
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
- VIB, Center for Microbiology, Leuven, Belgium
| | | | - Dieter Hackenberg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
- School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry, UK
| | - Lenka Steinbachová
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | - Christos Michaelidis
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | | | - Chandra Shekhar Misra
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tomokazu Kawashima
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Michael Borg
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna, BioCenter (VBC), Vienna, Austria
| | - Jacob Goldberg
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - Mark Johnson
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czech Republic
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
| | - Marek Mutwil
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
| |
Collapse
|
12
|
Ks R, Ra L, Rd W, Ha O, A M. Callose in sporogenesis: Novel composition of the inner spore wall in hornworts. PLANT SYSTEMATICS AND EVOLUTION = ENTWICKLUNGSGESCHICHTE UND SYSTEMATIK DER PFLANZEN 2020; 306:16. [PMID: 34079158 PMCID: PMC8167838 DOI: 10.1007/s00606-020-01631-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/08/2020] [Indexed: 05/06/2023]
Abstract
Sporogenesis is a developmental process that defines embryophytes and involves callose, especially in the production of the highly protective and recalcitrant spore/pollen wall. Until now, hornworts, leptosporangiate ferns and homosporous lycophytes are the only major plant groups in which the involvement of callose in spore development is equivocal. Through aniline blue fluorescence and immunogold labeling in the transmission electron microscope, we provide indisputable evidence for the presence of callose in the spore wall of five hornwort genera, but not in the derived Dendroceros, an epiphyte that produces multicellular spores. We present evidence that callose appears in the developing spore wall and is retained throughout development as a wall constituent of the intine or inner spore wall, a novel location for this polysaccharide in embryophytes. In endosporic and multicellular spores/pollen of Dendroceros, the liverwort Pellia, and Arabidopsis, callose appears in the newly formed cell walls only following the first mitotic division. Further probing for other wall polymers in hornworts reveals the presence of cellulose (Calcofluor fluorescence) in the spore intine, aperture and around the equatorial girdle. Further immunogold labeling with monoclonal antibodies identifies pectin and hemicellulose in hornwort intines. The persistence of callose, a typically transient cell wall constituent, with cellulose, pectins and hemicellulose in the intine, supports specialized functions of callose in spores of hornworts that include reduced water loss when spores are dry and mechanical flexibility to withstand desiccation.
Collapse
Affiliation(s)
- Renzaglia Ks
- Department of Plant Biology, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Lopez Ra
- Department of Plant Biology, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Welsh Rd
- Department of Plant Biology, Southern Illinois University Carbondale, Carbondale, Illinois, USA
| | - Owen Ha
- Department of Biological Sciences, University of Wisconsin Milwaukee, Milwaukee, Wisconsin, USA
| | - Merced A
- Institute of Neurobiology, University of Puerto Rico, San Juan, Puerto Rico, USA
| |
Collapse
|
13
|
Li YL, Zhang YF, Li DD, Shi QS, Lou Y, Yang ZN, Zhu J. Acyl-CoA synthetases from Physcomitrella, rice and Arabidopsis: different substrate preferences but common regulation by MS188 in sporopollenin synthesis. PLANTA 2019; 250:535-548. [PMID: 31111205 DOI: 10.1007/s00425-019-03189-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/14/2019] [Indexed: 05/28/2023]
Abstract
ACOS5, OsACOS12 and PpACOS6 are all capable of fatty acyl-CoA synthetase activity but exhibit different substrate preferences. The transcriptional regulation of ACOS for sporopollenin synthesis appears to have been conserved in Physcomitrella, rice and Arabidopsis during evolution. Sporopollenin is the major constituent of spore and pollen exines. In Arabidopsis, acyl-CoA synthetase 5 (ACOS5) is an essential enzyme for sporopollenin synthesis, and its orthologues are PpACOS6 from the moss Physcomitrella and OsACOS12 from monocot rice. However, knowledge regarding the evolutionary conservation and divergence of the ACOS gene in sporopollenin synthesis remains limited. In this study, we analysed the function and regulation of PpACOS6 and OsACOS12. A complementation test showed that OsACOS12 driven by the ACOS5 promoter could partially restore the male fertility of the acos5 mutant in Arabidopsis, while PpACOS6 did not rescue the acos5 phenotype. ACOS5, PpACOS6 and OsACOS12 all complemented the acyl-CoA synthetase-deficient yeast strain (YB525) phenotype, although they exhibited different substrate preferences. To understand the conservation of sporopollenin synthesis regulation, we constructed two constructs with ACOS5 driven by the OsACOS12 or PpACOS6 promoter. Both constructs could restore the fertility of acos5 plants. The MYB transcription factor MS188 from Arabidopsis directly regulates ACOS5. We found that MS188 could also bind the promoters of OsACOS12 and PpACOS6 and activate the genes driven by the promoters, suggesting that the transcriptional regulation of these genes was similar to that of ACOS5. These results show that the ACOS gene promoter region from Physcomitrella, rice and Arabidopsis has been functionally conserved during evolution, while the chain lengths of fatty acid-derived monomers of sporopollenin vary in different plant species.
Collapse
Affiliation(s)
- Yue-Ling Li
- Zhejiang Provincial Key Laboratory of Plant Evolutionary and Conservation, Taizhou University, Taizhou, 318000, China
- Institute of Ecology, Taizhou University, Taizhou, 318000, China
| | - Yan-Fei Zhang
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Dan-Dan Li
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Qiang-Sheng Shi
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yue Lou
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Zhong-Nan Yang
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Jun Zhu
- Shanghai Key Laboratory of Plant Molecule Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
| |
Collapse
|
14
|
Lamina shape does not correlate with lamina surface area: An analysis based on the simplified Gielis equation. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00666] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
15
|
|
16
|
Harrison CJ, Morris JL. The origin and early evolution of vascular plant shoots and leaves. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160496. [PMID: 29254961 PMCID: PMC5745332 DOI: 10.1098/rstb.2016.0496] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2017] [Indexed: 12/22/2022] Open
Abstract
The morphology of plant fossils from the Rhynie chert has generated longstanding questions about vascular plant shoot and leaf evolution, for instance, which morphologies were ancestral within land plants, when did vascular plants first arise and did leaves have multiple evolutionary origins? Recent advances combining insights from molecular phylogeny, palaeobotany and evo-devo research address these questions and suggest the sequence of morphological innovation during vascular plant shoot and leaf evolution. The evidence pinpoints testable developmental and genetic hypotheses relating to the origin of branching and indeterminate shoot architectures prior to the evolution of leaves, and demonstrates underestimation of polyphyly in the evolution of leaves from branching forms in 'telome theory' hypotheses of leaf evolution. This review discusses fossil, developmental and genetic evidence relating to the evolution of vascular plant shoots and leaves in a phylogenetic framework.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
Collapse
Affiliation(s)
- C Jill Harrison
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Jennifer L Morris
- School of Earth Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| |
Collapse
|
17
|
Kenrick P. Changing expressions: a hypothesis for the origin of the vascular plant life cycle. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170149. [PMID: 29254970 PMCID: PMC5745341 DOI: 10.1098/rstb.2017.0149] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2017] [Indexed: 02/06/2023] Open
Abstract
Plant life cycles underwent fundamental changes during the initial colonization of the land in the Early Palaeozoic, shaping the direction of evolution. Fossils reveal unanticipated diversity, including new variants of meiotic cell division and leafless gametophytes with mycorrhizal-like symbioses, rhizoids, vascular tissues and stomata. Exceptional fossils from the 407-Ma Rhynie chert (Scotland) play a key role in unlocking this diversity. These fossils are reviewed against progress in our understanding of the plant tree of life and recent advances in developmental genetics. Combining data from different sources sheds light on a switch in life cycle that gave rise to the vascular plants. One crucial step was the establishment of a free-living sporophyte from one that was an obligate matrotroph borne on the gametophyte. It is proposed that this difficult evolutionary transition was achieved through expansion of gene expression primarily from the gametophyte to the sporophyte, establishing a now extinct life cycle variant that was more isomorphic than heteromorphic. These changes also linked for the first time in one developmental system rhizoids, vascular tissues and stomata, putting in place the critical components that regulate transpiration and forming a physiological platform of primary importance to the diversification of vascular plants.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
Collapse
Affiliation(s)
- Paul Kenrick
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| |
Collapse
|
18
|
Buendía-Monreal M, Gillmor CS. The Times They Are A-Changin': Heterochrony in Plant Development and Evolution. FRONTIERS IN PLANT SCIENCE 2018; 9:1349. [PMID: 30283473 PMCID: PMC6157392 DOI: 10.3389/fpls.2018.01349] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/27/2018] [Indexed: 05/16/2023]
Abstract
Alterations in the timing of developmental programs during evolution, that lead to changes in the shape, or size of organs, are known as heterochrony. Heterochrony has been widely studied in animals, but has often been neglected in plants. During plant evolution, heterochronic shifts have played a key role in the origin and diversification of leaves, roots, flowers, and fruits. Heterochrony that results in a juvenile or simpler outcome is known as paedomorphosis, while an adult or more complex outcome is called peramorphosis. Mechanisms that alter developmental timing at the cellular level affect cell proliferation or differentiation, while those acting at the tissue or organismal level change endogenous aging pathways, morphogen signaling, and metabolism. We believe that wider consideration of heterochrony in the context of evolution will contribute to a better understanding of plant development.
Collapse
|
19
|
Taylor WA, Strother PK, Vecoli M, Al-Hajri S. Wall ultrastructure of the oldest embryophytic spores: Implications for early land plant evolution. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.revmic.2016.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
20
|
Jill Harrison C. Development and genetics in the evolution of land plant body plans. Philos Trans R Soc Lond B Biol Sci 2017; 372:20150490. [PMID: 27994131 PMCID: PMC5182422 DOI: 10.1098/rstb.2015.0490] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2016] [Indexed: 12/22/2022] Open
Abstract
The colonization of land by plants shaped the terrestrial biosphere, the geosphere and global climates. The nature of morphological and molecular innovation driving land plant evolution has been an enigma for over 200 years. Recent phylogenetic and palaeobotanical advances jointly demonstrate that land plants evolved from freshwater algae and pinpoint key morphological innovations in plant evolution. In the haploid gametophyte phase of the plant life cycle, these include the innovation of mulitcellular forms with apical growth and multiple growth axes. In the diploid phase of the life cycle, multicellular axial sporophytes were an early innovation priming subsequent diversification of indeterminate branched forms with leaves and roots. Reverse and forward genetic approaches in newly emerging model systems are starting to identify the genetic basis of such innovations. The data place plant evo-devo research at the cusp of discovering the developmental and genetic changes driving the radiation of land plant body plans.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.
Collapse
Affiliation(s)
- C Jill Harrison
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| |
Collapse
|
21
|
Wang H, Lin A, Gu W, Huan L, Gao S, Wang G. The sporulation of the green alga Ulva prolifera is controlled by changes in photosynthetic electron transport chain. Sci Rep 2016; 6:24923. [PMID: 27102955 PMCID: PMC4840353 DOI: 10.1038/srep24923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 04/06/2016] [Indexed: 11/13/2022] Open
Abstract
Sporulation and spore release are essential phases of the life cycle in algae and land plants. Ulva prolifera, which is an ideal organism for studying sporulation and spore release, was used as the experimental material in the present study. The determination of photosynthetic parameters, combined with microscopic observation, treatment with photosynthetic inhibitors, limitation of carbon acquisition, and protein mass spectrometry, was employed in this experiment. Cycle electron transport (CEF) was found enhanced at the onset of sporangia formation. The inhibition effect of dibromothymoquinone (DBMIB) towards sporulation was always strong during the sporulation process whereas the inhibition effect of 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea (DCMU) was continuously declined accompanied with the progress of sporulation. The changes of photosynthesis resulted from the limitation of CO2 acquisition could stimulate sporulation onset. Quantitative protein analysis showed that enzymes involved in carbon fixation, including RUBISCO and pyruvate orthophosphate dikinase, declined during sporogenesis, while proteins involved in sporulation, including tubulin and centrin, increased. These results suggest that enhanced cyclic electron flow (CEF) and oxidation of the plastoquinone pool are essential for sporangia formation onset, and changes in photosynthetic electron transport chain have significant impacts on sporulation of the green algae.
Collapse
Affiliation(s)
- Hui Wang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Apeng Lin
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Wenhui Gu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.,Nantong Branch, Institute of Oceanology, Chinese Academy of Sciences, Nantong 226006, China
| | - Li Huan
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Shan Gao
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Guangce Wang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| |
Collapse
|
22
|
Abstract
UNLABELLED • PREMISE OF THE STUDY Zygotes of Coleochaete are provisioned by the maternal thallus before undergoing 3-5 rounds of division to produce 8-32 zoospores. An understanding of the selective forces favoring postzygotic divisions would be relevant not only to the interpretation of Coleochaete life history but also to the origin of a multicellular diploid phase in embryophytes.• METHODS Simple optimization models are developed of the number of zygotes per maternal thallus and number of zoospores per zygote.• KEY RESULTS Zygotic mitosis is favored once zygotic size exceeds a threshold, but natural selection usually promotes investment in additional zygotes before zygotes reach this threshold. Factors that favor production of fewer, larger zygotes include multiple paternity, low fecundity, and accessory costs of zygote production. Such factors can result in zygotes exceeding the size at which zygotic mitosis becomes profitable.• CONCLUSIONS Coleochaete may possess large zygotes that undergo multiple fission because of accessory costs associated with matrotrophy, including costs of cortical cells and unfertilized oogonia. The unpredictability of fertilization on land is proposed to have increased accessory costs from unfertilized ova and, as a consequence, to have favored the production of larger zygotes that underwent postzygotic division to produce diploid sporophytes.
Collapse
Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138 USA
| |
Collapse
|
23
|
Edwards D, Morris JL, Richardson JB, Kenrick P. Cryptospores and cryptophytes reveal hidden diversity in early land floras. THE NEW PHYTOLOGIST 2014; 202:50-78. [PMID: 24410730 DOI: 10.1111/nph.12645] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/04/2013] [Indexed: 05/18/2023]
Abstract
Cryptospores, recovered from Ordovician through Devonian rocks, differ from trilete spores in possessing distinctive configurations (i.e. hilate monads, dyads, and permanent tetrads). Their affinities are contentious, but knowledge of their relationships is essential to understanding the nature of the earliest land flora. This review brings together evidence about the source plants, mostly obtained from spores extracted from minute, fragmented, yet exceptionally anatomically preserved fossils. We coin the term 'cryptophytes' for plants that produced the cryptospores and show them to have been simple terrestrial organisms of short stature (i.e. millimetres high). Two lineages are currently recognized. Partitatheca shows a combination of characters (e.g. spo-rophyte bifurcation, stomata, and dyads) unknown in plants today. Lenticulatheca encompasses discoidal sporangia containing monads formed from dyads with ultrastructure closer to that of higher plants, as exemplified by Cooksonia. Other emerging groupings are less well characterized, and their precise affinities to living clades remain unclear. Some may be stem group embryophytes or tracheophytes. Others are more closely related to the bryophytes, but they are not bryophytes as defined by extant representatives. Cryptophytes encompass a pool of diversity from which modern bryophytes and vascular plants emerged, but were competitively replaced by early tracheophytes. Sporogenesis always produced either dyads or tetrads, indicating strict genetic control. The long-held consensus that tetrads were the archetypal condition in land plants is challenged.
Collapse
Affiliation(s)
- Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Jennifer L Morris
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
- Department of Animal and Plant Sciences, Sheffield University, Western Bank, Sheffield, S10 2TN, UK
| | - John B Richardson
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| | - Paul Kenrick
- Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK
| |
Collapse
|
24
|
Graham L, Lewis LA, Taylor W, Wellman C, Cook M. Early Terrestrialization: Transition from Algal to Bryophyte Grade. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-94-007-6988-5_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
|
25
|
Tohge T, Watanabe M, Hoefgen R, Fernie AR. The evolution of phenylpropanoid metabolism in the green lineage. Crit Rev Biochem Mol Biol 2013; 48:123-52. [PMID: 23350798 DOI: 10.3109/10409238.2012.758083] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Phenolic secondary metabolites are only produced by plants wherein they play important roles in both biotic and abiotic defense in seed plants as well as being potentially important bioactive compounds with both nutritional and medicinal benefits reported for animals and humans as a consequence of their potent antioxidant activity. During the long evolutionary period in which plants have adapted to the environmental niches in which they exist (and especially during the evolution of land plants from their aquatic algal ancestors), several strategies such as gene duplication and convergent evolution have contributed to the evolution of this pathway. In this respect, diversity and redundancy of several key genes of phenolic secondary metabolism such as polyketide synthases, cytochrome P450s, Fe(2+)/2-oxoglutarate-dependent dioxygenases and UDP-glycosyltransferases have played an essential role. Recent technical developments allowing affordable whole genome sequencing as well as a better inventory of species-by-species chemical diversity have resulted in a dramatic increase in the number of tools we have to assess how these pathways evolved. In parallel, reverse genetics combined with detailed molecular phenotyping is allowing us to elucidate the functional importance of individual genes and metabolites and by this means to provide further mechanistic insight into their biological roles. In this review, phenolic metabolite-related gene sequences (for a total of 65 gene families including shikimate biosynthetic genes) are compared across 23 independent species, and the phenolic metabolic complement of various plant species are compared with one another, in attempt to better understand the evolution of diversity in this crucial pathway.
Collapse
Affiliation(s)
- Takayuki Tohge
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
| | | | | | | |
Collapse
|
26
|
Ligrone R, Duckett JG, Renzaglia KS. Major transitions in the evolution of early land plants: a bryological perspective. ANNALS OF BOTANY 2012; 109:851-71. [PMID: 22356739 PMCID: PMC3310499 DOI: 10.1093/aob/mcs017] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 01/06/2012] [Indexed: 05/02/2023]
Abstract
Background Molecular phylogeny has resolved the liverworts as the earliest-divergent clade of land plants and mosses as the sister group to hornworts plus tracheophytes, with alternative topologies resolving the hornworts as sister to mosses plus tracheophytes less well supported. The tracheophytes plus fossil plants putatively lacking lignified vascular tissue form the polysporangiophyte clade. Scope This paper reviews phylogenetic, developmental, anatomical, genetic and paleontological data with the aim of reconstructing the succession of events that shaped major land plant lineages. Conclusions Fundamental land plant characters primarily evolved in the bryophyte grade, and hence the key to a better understanding of the early evolution of land plants is in bryophytes. The last common ancestor of land plants was probably a leafless axial gametophyte bearing simple unisporangiate sporophytes. Water-conducting tissue, if present, was restricted to the gametophyte and presumably consisted of perforate cells similar to those in the early-divergent bryophytes Haplomitrium and Takakia. Stomata were a sporophyte innovation with the possible ancestral functions of producing a transpiration-driven flow of water and solutes from the parental gametophyte and facilitating spore separation before release. Stomata in mosses, hornworts and polysporangiophytes are viewed as homologous, and hence these three lineages are collectively referred to as the 'stomatophytes'. An indeterminate sporophyte body (the sporophyte shoot) developing from an apical meristem was the key innovation in polysporangiophytes. Poikilohydry is the ancestral condition in land plants; homoiohydry evolved in the sporophyte of polysporangiophytes. Fungal symbiotic associations ancestral to modern arbuscular mycorrhizas evolved in the gametophytic generation before the separation of major present-living lineages. Hydroids are imperforate water-conducting cells specific to advanced mosses. Xylem vascular cells in polysporangiophytes arose either from perforate cells or de novo. Food-conducting cells were a very early innovation in land plant evolution. The inferences presented here await testing by molecular genetics.
Collapse
Affiliation(s)
- Roberto Ligrone
- Dipartimento di Scienze ambientali, Seconda Università di Napoli, via Vivaldi 43, Caserta, Italy.
| | | | | |
Collapse
|
27
|
Graham LE, Arancibia-Avila P, Taylor WA, Strother PK, Cook ME. Aeroterrestrial Coleochaete (Streptophyta, Coleochaetales) models early plant adaptation to land. AMERICAN JOURNAL OF BOTANY 2012; 99:130-44. [PMID: 22210844 DOI: 10.3732/ajb.1100245] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
PREMISE OF THE STUDY The streptophyte water-to-land transition was a pivotal, but poorly understood event in Earth history. While some early-diverging modern streptophyte algae are aeroterrestrial (living in subaerial habitats), aeroterrestrial survival had not been tested for Coleochaete, widely regarded as obligately aquatic and one of the extant green algal genera most closely related to embryophytes. This relationship motivated a comparison of aeroterrestrial Coleochaete to lower Paleozoic microfossils whose relationships have been uncertain. METHODS We tested the ability of two species of the experimentally tractable, complex streptophyte algal genus Coleochaete Bréb. to (1) grow and reproduce when cultivated under conditions that mimic humid subaerial habitats, (2) survive desiccation for some period of time, and (3) produce degradation-resistant remains comparable to enigmatic Cambrian microfossils. KEY RESULTS When grown on mineral agar media or on quartz sand, both species displayed bodies structurally distinct from those expressed in aquatic habitats. Aeroterrestrial Coleochaete occurred as hairless, multistratose, hemispherical bodies having unistratose lobes or irregular clusters of cells with thick, layered, and chemically resistant walls that resemble certain enigmatic lower Paleozoic microfossils. Whether grown under humid conditions or air-dried for a week, then exposed to liquid water, aeroterrestrial Coleochaete produced typical asexual zoospores and germlings. Cells that had been air-dried for periods up to several months maintained their integrity and green pigmentation. CONCLUSIONS Features of modern aeroterrestrial Coleochaete suggest that ancient complex streptophyte algae could grow and reproduce in moist subaerial habitats, persist through periods of desiccation, and leave behind distinctive microfossil remains.
Collapse
Affiliation(s)
- Linda E Graham
- Department of Botany, University of Wisconsin, Madison, 53706-1381, USA.
| | | | | | | | | |
Collapse
|
28
|
Brown RC, Lemmon BE. Dividing without centrioles: innovative plant microtubule organizing centres organize mitotic spindles in bryophytes, the earliest extant lineages of land plants. AOB PLANTS 2011; 2011:plr028. [PMID: 22476498 PMCID: PMC3240993 DOI: 10.1093/aobpla/plr028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 11/03/2011] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS As remnants of the earliest land plants, the bryophytes (liverworts, mosses and hornworts) are important in understanding microtubule organization in plant cells. Land plants have an anastral mitotic spindle that forms in the absence of centrosomes, and a cytokinetic apparatus comprised of a predictive preprophase band (PPB) before mitosis and a phragmoplast after mitosis. These microtubule arrays have no counterpart in animal cells and the nature of the plant microtubule organizing centre (MTOC) remained an enigma for many years until antibodies to γ-tubulin, an essential component of the MTOC in all eukaryotes, became available for tracing the origin of microtubule arrays. METHODOLOGY We used immunofluorescence techniques to colocalize γ-tubulin, microtubules and chromosomes in mitotic cells of a representative liverwort, moss and hornwort to study the organization of microtubules during mitotic cell division. PRINCIPAL RESULTS THE FUTURE DIVISION SITE IS MARKED BY A PPB IN ALL TAXA BUT THE MTOCS INITIALLY GENERATING THE HALF SPINDLES DIFFER: polar organizers in the liverwort, plastid MTOCs in the hornwort, and nuclear envelope-associated MTOCs in the moss. By mid-prophase, the forming spindles become more similar as γ-tubulin begins to spread around the polar regions of the nuclear envelope. CONCLUSIONS Regardless of origin, mature metaphase spindles are identical and indistinguishable from the typical anastral spindle of higher plants with broad polar regions consisting of numerous subsets of converging microtubules. A curious phenomenon of plant spindles, true of bryophytes as well as higher plants, is the movement of γ-tubulin into the metaphase spindle itself. The bipolar arrays of phragmoplast microtubules are organized by diffuse γ-tubulin located at proximal surfaces of reforming nuclear envelopes. Phragmoplast development appears similar in the three taxa and to vascular plants as well.
Collapse
|