1
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Tsuda K. Evolution of the sporophyte shoot axis and functions of TALE HD transcription factors in stem development. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102594. [PMID: 38943830 DOI: 10.1016/j.pbi.2024.102594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 05/24/2024] [Accepted: 06/10/2024] [Indexed: 07/01/2024]
Abstract
The stem is one of the major organs in seed plants and is important for plant survival as well as in agriculture. However, due to the lack of clear external landmarks in many species, its developmental and evolutionary processes are understudied compared to other organs. Recent approaches tackling these problems, especially those focused on KNOX1 and BLH transcription factors belonging to the TALE homeodomain superfamily have started unveiling the patterning process of nodes and internodes by connecting previously accumulated knowledge on lateral organ regulators. Fossil records played crucial roles in understanding the evolutionary process of the stem. The aim of this review is to introduce how the stem evolved from ancestorial sporophyte axes and to provide frameworks for future efforts in understanding the developmental process of this elusive but pivotal organ.
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Affiliation(s)
- Katsutoshi Tsuda
- Plant Cytogenetics Laboratory, Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, School of Life Science, Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan.
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2
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Coiro M. Embracing uncertainty: The way forward in plant fossil phylogenetics. AMERICAN JOURNAL OF BOTANY 2024; 111:e16282. [PMID: 38334302 DOI: 10.1002/ajb2.16282] [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: 09/30/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 02/10/2024]
Abstract
Although molecular phylogenetics remains the most widely used method of inferring the evolutionary history of living groups, the last decade has seen a renewed interest in morphological phylogenetics, mostly driven by the promises that integrating the fossil record in phylogenetic trees offers to our understanding of macroevolutionary processes and dynamics and the possibility that the inclusion of fossil taxa could lead to more accurate phylogenetic hypotheses. The plant fossil record presents some challenges to its integration in a phylogenetic framework. Phylogenies including plant fossils often retrieve uncertain relationships with low support, or lack of resolution. This low support is due to the pervasiveness of morphological convergence among plant organs and the fragmentary nature of many plant fossils, and it is often perceived as a fundamental weakness reducing the utility of plant fossils in phylogenetics. Here I discuss the importance of uncertainty in morphological phylogenetics and how we can identify important information from different patterns and types of uncertainty. I also review a set of methodologies that can allow us to understand the causes underpinning uncertainty and how these practices can help us to further our knowledge of plant fossils. I also propose that a new visual language, including the use of networks instead of trees, represents an improvement on the old visualization based on consensus trees and more adequately serves phylogeneticists working with plant fossils. This set of methods and visualization tools represents an important way forward in a fundamental field for our understanding of the evolutionary history of plants.
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Affiliation(s)
- Mario Coiro
- Department of Palaeontology, University of Vienna, Vienna, Austria
- Ronin Institute for Independent Scholarship, Montclair, NJ, USA
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3
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Pfeiler KC, Tomescu AMF. Mosaic assembly of regulatory programs for vascular cambial growth: a view from the Early Devonian. THE NEW PHYTOLOGIST 2023; 240:529-541. [PMID: 37491742 DOI: 10.1111/nph.19146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/30/2023] [Indexed: 07/27/2023]
Abstract
Evidence for secondary growth extends into the Early Devonian, 407 million years ago, raising questions about tempo and mode of origination of this key developmental feature. To address such questions, we analyze anatomy in the four oldest fossil plants with well-characterized woody tissues; one of these represents a new genus, described here formally. The new fossil is documented using the cellulose acetate peel technique and associated methods. We use the paradigm of structural fingerprints to identify developmental components of cambial growth based on fossil anatomy. We integrate developmental inferences within a theoretical framework of modular regulation of secondary growth. The fossils possess structural fingerprints consistent with four different combinations of regulatory mechanisms (modules) acting in cambial growth, representing four distinct modes of secondary growth. The different modes of secondary growth demonstrate that cambial growth is an assemblage of regulatory modules whose deployment followed a mosaic pattern across woody plants, which may represent ancestors of younger lineages that exhibit woody growth. The diverse modes of wood development occupy a wide morphospace in the anatomy of wood in the Early Devonian, suggesting that the origins of secondary growth and of its modular components pre-date this interval.
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Affiliation(s)
- Kelly C Pfeiler
- Department of Biological Sciences, California State Polytechnic University Humboldt, Arcata, CA, 95521, USA
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, 66045, USA
| | - Alexandru M F Tomescu
- Department of Biological Sciences, California State Polytechnic University Humboldt, Arcata, CA, 95521, USA
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4
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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.
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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
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5
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Kapoor B, Kumar P, Verma V, Irfan M, Sharma R, Bhargava B. How plants conquered land: evolution of terrestrial adaptation. J Evol Biol 2023; 36:5-14. [PMID: 36083189 DOI: 10.1111/jeb.14062] [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: 11/15/2021] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 01/11/2023]
Abstract
The transition of plants from water to land is considered one of the most significant events in the evolution of life on Earth. The colonization of land by plants, accompanied by their morphological, physiological and developmental changes, resulted in plant biodiversity. Besides significantly influencing oxygen levels in the air and on land, plants manufacture organic matter from CO2 and water with the help of sunlight, paving the way for the diversification of nonplant lineages ranging from microscopic organisms to animals. Land plants regulate the climate by adjusting total biomass and energy flow. At the genetic level, these innovations are achieved through the rearrangement of pre-existing genetic information. Advances in genome sequencing technology are revamping our understanding of plant evolution. This study highlights the morphological and genomic innovations that allow plants to integrate life on Earth.
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Affiliation(s)
- Bhuvnesh Kapoor
- Department of Biotechnology, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan, Himachal Pradesh, India
| | - Pankaj Kumar
- Department of Biotechnology, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan, Himachal Pradesh, India
| | - Vipasha Verma
- Agrotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India
| | - Mohammad Irfan
- Plant Biology Section, School of Integrative Plant Sciences, Cornell University, Ithaca, New York, USA
| | - Rajnish Sharma
- Department of Biotechnology, Dr. Y.S. Parmar University of Horticulture and Forestry, Solan, Himachal Pradesh, India
| | - Bhavya Bhargava
- Agrotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, India
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6
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Woudenberg S, Renema J, Tomescu AMF, De Rybel B, Weijers D. Deep origin and gradual evolution of transporting tissues: Perspectives from across the land plants. PLANT PHYSIOLOGY 2022; 190:85-99. [PMID: 35904762 PMCID: PMC9434249 DOI: 10.1093/plphys/kiac304] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/08/2022] [Indexed: 05/31/2023]
Abstract
The evolution of transporting tissues was an important innovation in terrestrial plants that allowed them to adapt to almost all nonaquatic environments. These tissues consist of water-conducting cells and food-conducting cells and bridge plant-soil and plant-air interfaces over long distances. The largest group of land plants, representing about 95% of all known plant species, is associated with morphologically complex transporting tissue in plants with a range of additional traits. Therefore, this entire clade was named tracheophytes, or vascular plants. However, some nonvascular plants possess conductive tissues that closely resemble vascular tissue in their organization, structure, and function. Recent molecular studies also point to a highly conserved toolbox of molecular regulators for transporting tissues. Here, we reflect on the distinguishing features of conductive and vascular tissues and their evolutionary history. Rather than sudden emergence of complex, vascular tissues, plant transporting tissues likely evolved gradually, building on pre-existing developmental mechanisms and genetic components. Improved knowledge of the intimate structure and developmental regulation of transporting tissues across the entire taxonomic breadth of extant plant lineages, combined with more comprehensive documentation of the fossil record of transporting tissues, is required for a full understanding of the evolutionary trajectory of transporting tissues.
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Affiliation(s)
| | | | - Alexandru M F Tomescu
- Department of Biological Sciences, California State Polytechnic University–Humboldt, Arcata, California 95521, USA
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Perico C, Tan S, Langdale JA. Developmental regulation of leaf venation patterns: monocot versus eudicots and the role of auxin. THE NEW PHYTOLOGIST 2022; 234:783-803. [PMID: 35020214 PMCID: PMC9994446 DOI: 10.1111/nph.17955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Organisation and patterning of the vascular network in land plants varies in different taxonomic, developmental and environmental contexts. In leaves, the degree of vascular strand connectivity influences both light and CO2 harvesting capabilities as well as hydraulic capacity. As such, developmental mechanisms that regulate leaf venation patterning have a direct impact on physiological performance. Development of the leaf venation network requires the specification of procambial cells within the ground meristem of the primordium and subsequent proliferation and differentiation of the procambial lineage to form vascular strands. An understanding of how diverse venation patterns are manifest therefore requires mechanistic insight into how procambium is dynamically specified in a growing leaf. A role for auxin in this process was identified many years ago, but questions remain. In this review we first provide an overview of the diverse venation patterns that exist in land plants, providing an evolutionary perspective. We then focus on the developmental regulation of leaf venation patterns in angiosperms, comparing patterning in eudicots and monocots, and the role of auxin in each case. Although common themes emerge, we conclude that the developmental mechanisms elucidated in eudicots are unlikely to fully explain how parallel venation patterns in monocot leaves are elaborated.
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Affiliation(s)
- Chiara Perico
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
| | - Sovanna Tan
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
| | - Jane A. Langdale
- Department of Plant SciencesUniversity of OxfordSouth Parks RdOxfordOX1 3RBUK
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8
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Tomescu AMF, Rothwell GW. Fossils and plant evolution: structural fingerprints and modularity in the evo-devo paradigm. EvoDevo 2022; 13:8. [PMID: 35236418 PMCID: PMC8892741 DOI: 10.1186/s13227-022-00192-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/29/2022] [Indexed: 11/30/2022] Open
Abstract
Fossils constitute the principal repository of data that allow for independent tests of hypotheses of biological evolution derived from observations of the extant biota. Traditionally, transformational series of structure, consisting of sequences of fossils of the same lineage through time, have been employed to reconstruct and interpret morphological evolution. More recently, a move toward an updated paradigm was fueled by the deliberate integration of developmental thinking in the inclusion of fossils in reconstruction of morphological evolution. The vehicle for this is provided by structural fingerprints-recognizable morphological and anatomical structures generated by (and reflective of) the deployment of specific genes and regulatory pathways during development. Furthermore, because the regulation of plant development is both modular and hierarchical in nature, combining structural fingerprints recognized in the fossil record with our understanding of the developmental regulation of those structures produces a powerful tool for understanding plant evolution. This is particularly true when the systematic distribution of specific developmental regulatory mechanisms and modules is viewed within an evolutionary (paleo-evo-devo) framework. Here, we discuss several advances in understanding the processes and patterns of evolution, achieved by tracking structural fingerprints with their underlying regulatory modules across lineages, living and fossil: the role of polar auxin regulation in the cellular patterning of secondary xylem and the parallel evolution of arborescence in lycophytes and seed plants; the morphology and life history of early polysporangiophytes and tracheophytes; the role of modularity in the parallel evolution of leaves in euphyllophytes; leaf meristematic activity and the parallel evolution of venation patterns among euphyllophytes; mosaic deployment of regulatory modules and the diverse modes of secondary growth of euphyllophytes; modularity and hierarchy in developmental regulation and the evolution of equisetalean reproductive morphology. More generally, inclusion of plant fossils in the evo-devo paradigm has informed discussions on the evolution of growth patterns and growth responses, sporophyte body plans and their homology, sequences of character evolution, and the evolution of reproductive systems.
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Affiliation(s)
- Alexandru M. F. Tomescu
- Department of Biological Sciences, California Polytechnic State University Humboldt, Arcata, CA 95521 USA
| | - Gar W. Rothwell
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701 USA
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331 USA
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9
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Smith SD, Blackman BK. From deep roots to new blooms: The ever-growing field of evo-devo across land plants. Evol Dev 2021; 23:119-122. [PMID: 33974350 DOI: 10.1111/ede.12378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Stacey D Smith
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Benjamin K Blackman
- Department of Plant and Microbial Biology, University of California, Berkeley, California, USA
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10
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Tomescu AMF, Groover AT. Mosaic modularity: an updated perspective and research agenda for the evolution of vascular cambial growth. THE NEW PHYTOLOGIST 2019; 222:1719-1735. [PMID: 30552764 DOI: 10.1111/nph.15640] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Secondary growth from a vascular cambium, present today only in seed plants and isoetalean lycophytes, has a 400-million-yr evolutionary history that involves considerably broader taxonomic diversity, most of it hidden in the fossil record. Approaching vascular cambial growth as a complex developmental process, we review data from living plants and fossils that reveal diverse modes of secondary growth. These are consistent with a modular nature of secondary growth, when considered as a tracheophyte-wide structural feature. This modular perspective identifies putative constituent developmental modules of cambial growth, for which we review developmental anatomy and regulation. Based on these data, we propose a hypothesis that explains the sources of diversity of secondary growth, considered across the entire tracheophyte clade, and opens up new avenues for exploring the origin of secondary growth. In this hypothesis, various modes of secondary growth reflect a mosaic pattern of expression of different developmental-regulatory modules among different lineages. We outline an approach that queries three information systems (living seed plants, living seed-free plants, and fossils) and integrates data on developmental regulation, anatomy, gene evolution and phylogeny to test the mosaic modularity hypothesis and its implications, and to inform efforts aimed at understanding the evolution of secondary growth.
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Affiliation(s)
- Alexandru M F Tomescu
- Department of Biological Sciences, Humboldt State University, Arcata, CA, 95521, USA
| | - Andrew T Groover
- Pacific Southwest Research Station, USDA Forest Service, Davis, CA, 95618, USA
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
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11
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Rudall PJ, Bateman RM. Leaf surface development and the plant fossil record: stomatal patterning in Bennettitales. Biol Rev Camb Philos Soc 2019; 94:1179-1194. [DOI: 10.1111/brv.12497] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 11/28/2022]
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12
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13
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Elgorriaga A, Escapa IH, Rothwell GW, Tomescu AMF, Rubén Cúneo N. Origin of Equisetum: Evolution of horsetails (Equisetales) within the major euphyllophyte clade Sphenopsida. AMERICAN JOURNAL OF BOTANY 2018; 105:1286-1303. [PMID: 30025163 DOI: 10.1002/ajb2.1125] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Equisetum is the sole living representative of Sphenopsida, a clade with impressive species richness, a long fossil history dating back to the Devonian, and obscure relationships with other living pteridophytes. Based on molecular data, the crown group age of Equisetum is mid-Paleogene, although fossils with possible crown synapomorphies appear in the Triassic. The most widely circulated hypothesis states that the lineage of Equisetum derives from calamitaceans, but no comprehensive phylogenetic studies support the claim. Using a combined approach, we provide a comprehensive phylogenetic analysis of Equisetales, with special emphasis on the origin of genus Equisetum. METHODS We performed parsimony phylogenetic analyses to address relationships of 43 equisetalean species (15 extant, 28 extinct) using a combination of morphological and molecular characters. KEY RESULTS We recovered Equisetaceae + Neocalamites as sister to Calamitaceae + a clade of Angaran and Gondwanan horsetails, with the four groups forming a clade that is sister to Archaeocalamitaceae. The estimated age for the Equisetum crown group is mid-Mesozoic. CONCLUSIONS Modern horsetails are not nested within calamitaceans; instead, both groups have explored independent evolutionary trajectories since the Carboniferous. Diverse fossil taxon sampling helps to shed light on the position and relationships of equisetalean lineages, of which only a tiny remnant is present within the extant flora. Understanding these relationships and early character configurations of ancient plant clades as Equisetales provide useful tests of hypotheses about overall phylogenetic relationships of euphyllophytes and foundations for future tests of molecular dates with paleontological data.
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Affiliation(s)
- Andrés Elgorriaga
- CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Chubut, 9100, Argentina
| | - Ignacio H Escapa
- CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Chubut, 9100, Argentina
| | - Gar W Rothwell
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
| | - Alexandru M F Tomescu
- Department of Biological Sciences, Humboldt State University, Arcata, CA, 95521, USA
| | - N Rubén Cúneo
- CONICET, Museo Paleontológico Egidio Feruglio, Trelew, Chubut, 9100, Argentina
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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: 24] [Impact Index Per Article: 4.0] [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.
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15
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Matsunaga KKS, Cullen NP, Tomescu AMF. Vascularization of the Selaginella rhizophore: anatomical fingerprints of polar auxin transport with implications for the deep fossil record. THE NEW PHYTOLOGIST 2017; 216:419-428. [PMID: 28225170 DOI: 10.1111/nph.14478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/16/2017] [Indexed: 06/06/2023]
Abstract
The Selaginella rhizophore is a unique and enigmatic organ whose homology with roots, shoots, or neither of the two remains unresolved. Nevertheless, rhizophore-like organs have been documented in several fossil lycophytes. Here we test the homology of these organs through comparisons with the architecture of rhizophore vascularization in Selaginella. We document rhizophore vascularization in nine Selaginella species using cleared whole-mounts and histological sectioning combined with three-dimensional reconstruction. Three patterns of rhizophore vascularization are present in Selaginella and each is comparable to those observed in rhizophore-like organs of fossil lycophytes. More compellingly, we found that all Selaginella species sampled exhibit tracheids that arc backward from the stem and side branch into the rhizophore base. This tracheid curvature is consistent with acropetal auxin transport previously documented in the rhizophore and is indicative of the redirection of basipetal auxin from the shoot into the rhizophore during development. The tracheid curvature observed in Selaginella rhizophores provides an anatomical fingerprint for the patterns of auxin flow that underpin rhizophore development. Similar tracheid geometry may be present and should be searched for in fossils to address rhizophore homology and the conservation of auxin-related developmental mechanisms from early stages of lycophyte evolution.
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Affiliation(s)
- Kelly K S Matsunaga
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Nevin P Cullen
- Department of Biology, San Francisco State University, San Francisco, CA, 94132, USA
| | - Alexandru M F Tomescu
- Department of Biological Sciences, Humboldt State University, Arcata, CA, 95521, USA
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16
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Hetherington AJ, Dolan L. The evolution of lycopsid rooting structures: conservatism and disparity. THE NEW PHYTOLOGIST 2017; 215:538-544. [PMID: 27901273 DOI: 10.1111/nph.14324] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/16/2016] [Indexed: 05/25/2023]
Abstract
Contents 538 I. 538 II. 539 III. 541 IV. 542 543 References 543 SUMMARY: The evolution of rooting structures was a crucial event in Earth's history, increasing the ability of plants to extract water, mine for nutrients and anchor above-ground shoot systems. Fossil evidence indicates that roots evolved at least twice among vascular plants, in the euphyllophytes and independently in the lycophytes. Here, we review the anatomy and evolution of lycopsid rooting structures. Highlighting recent discoveries made with fossils we suggest that the evolution of lycopsid rooting structures displays two contrasting patterns - conservatism and disparity. The structures termed roots have remained structurally similar despite hundreds of millions of years of evolution - an example of remarkable conservatism. By contrast, and over the same time period, the organs that give rise to roots have diversified, resulting in the evolution of numerous novel and disparate organs.
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Affiliation(s)
- Alexander J Hetherington
- Department of Plant Sciences, University of Oxford, Oxford South Parks Road, Oxford, OX1 3RB, UK
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, Oxford South Parks Road, Oxford, OX1 3RB, UK
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17
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Fernández-Mazuecos M, Glover BJ. The evo-devo of plant speciation. Nat Ecol Evol 2017; 1:110. [DOI: 10.1038/s41559-017-0110] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/07/2017] [Indexed: 11/09/2022]
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18
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Tomescu AMF, Escapa IH, Rothwell GW, Elgorriaga A, Cúneo NR. Developmental programmes in the evolution of Equisetum reproductive morphology: a hierarchical modularity hypothesis. ANNALS OF BOTANY 2017; 119:489-505. [PMID: 28365757 PMCID: PMC5458719 DOI: 10.1093/aob/mcw273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/19/2016] [Accepted: 11/29/2016] [Indexed: 05/30/2023]
Abstract
BACKGROUND The origin of the Equisetum strobilus has long been debated and the fossil record has played an important role in these discussions. The paradigm underlying these debates has been the perspective of the shoot as node-internode alternation, with sporangiophores attached at nodes. However, fossils historically excluded from these discussions (e.g. Cruciaetheca and Peltotheca ) exhibit reproductive morphologies that suggest attachment of sporangiophores along internodes, challenging traditional views. This has rekindled discussions around the evolution of the Equisetum strobilus, but lack of mechanistic explanations has led discussions to a stalemate. SCOPE A shift of focus from the node-internode view to a perspective emphasizing the phytomer as a modular unit of the shoot, frees the debate of homology constraints on the nature of the sporangiophore and inspires a mechanism-based hypothesis for the evolution of the strobilus. The hypothesis, drawing on data from developmental anatomy, regulatory mechanisms and the fossil record, rests on two tenets: (1) the equisetalean shoot grows by combined activity of the apical meristem, laying down the phytomer pattern, and intercalary meristems responsible for internode elongation; and (2) activation of reproductive growth programmes in the intercalary meristem produces sporangiophore whorls along internodes. CONCLUSIONS Hierarchical expression of regulatory modules responsible for (1) transition to reproductive growth; (2) determinacy of apical growth; and (3) node-internode differentiation within phytomers, can explain reproductive morphologies illustrated by Cruciaetheca (module 1 only), Peltotheca (modules 1 and 2) and Equisetum (all three modules). This model has implications - testable by studies of the fossil record, phylogeny and development - for directionality in the evolution of reproductive morphology ( Cruciaetheca - Peltotheca - Equisetum ) and for the homology of the Equisetum stobilus. Furthermore, this model implies that sporangiophore development is independent of node-internode identity, suggesting that the sporangiophore represents the expression of an ancestral euphyllophyte developmental module that pre-dates the evolution of leaves.
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Key Words
- Cruciaetheca, development, Equisetum, Equisetales, evolution, fossil, hierarchy, modularity, Peltotheca, phytomer, sphenopsid, strobilus
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Affiliation(s)
| | - Ignacio H. Escapa
- CONICET, Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100 Trelew, Chubut, Argentina
| | - Gar W. Rothwell
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
- Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701, USA
| | - Andrés Elgorriaga
- Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100 Trelew, Chubut, Argentina
| | - N. Rubén Cúneo
- Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100 Trelew, Chubut, Argentina
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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'.
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Affiliation(s)
- C Jill Harrison
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
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21
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Networks of highly branched stigmarian rootlets developed on the first giant trees. Proc Natl Acad Sci U S A 2016; 113:6695-700. [PMID: 27226309 DOI: 10.1073/pnas.1514427113] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lycophyte trees, up to 50 m in height, were the tallest in the Carboniferous coal swamp forests. The similarity in their shoot and root morphology led to the hypothesis that their rooting (stigmarian) systems were modified leafy shoot systems, distinct from the roots of all other plants. Each consists of a branching main axis covered on all sides by lateral structures in a phyllotactic arrangement; unbranched microphylls developed from shoot axes, and largely unbranched stigmarian rootlets developed from rhizomorphs axes. Here, we reexamined the morphology of extinct stigmarian systems preserved as compression fossils and in coal balls from the Carboniferous period. Contrary to the long-standing view of stigmarian systems, where shoot-like rhizomorph axes developed largely unbranched, root-hairless rootlets, here we report that stigmarian rootlets were highly branched, developed at a density of ∼25,600 terminal rootlets per meter of rhizomorph, and were covered in root hairs. Furthermore, we show that this architecture is conserved among their only extant relatives, herbaceous plants in the Isoetes genus. Therefore, despite the difference in stature and the time that has elapsed, we conclude that both extant and extinct rhizomorphic lycopsids have the same rootlet system architecture.
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Matsunaga KKS, Tomescu AMF. Root evolution at the base of the lycophyte clade: insights from an Early Devonian lycophyte. ANNALS OF BOTANY 2016; 117:585-98. [PMID: 26921730 PMCID: PMC4817433 DOI: 10.1093/aob/mcw006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/21/2015] [Accepted: 11/30/2015] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS The evolution of complex rooting systems during the Devonian had significant impacts on global terrestrial ecosystems and the evolution of plant body plans. However, detailed understanding of the pathways of root evolution and the architecture of early rooting systems is currently lacking. We describe the architecture and resolve the structural homology of the rooting system of an Early Devonian basal lycophyte. Insights gained from these fossils are used to address lycophyte root evolution and homology. METHODS Plant fossils are preserved as carbonaceous compressions at Cottonwood Canyon (Wyoming), in the Lochkovian-Pragian (∼411 Ma; Early Devonian) Beartooth Butte Formation. We analysed 177 rock specimens and documented morphology, cuticular anatomy and structural relationships, as well as stratigraphic position and taphonomic conditions. KEY RESULTS The rooting system of the Cottonwood Canyon lycophyte is composed of modified stems that bear fine, dichotomously branching lateral roots. These modified stems, referred to as root-bearing axes, are produced at branching points of the above-ground shoot system. Root-bearing axes preserved in growth position exhibit evidence of positive gravitropism, whereas the lateral roots extend horizontally. Consistent recurrence of these features in successive populations of the plant preserved in situ demonstrates that they represent constitutive structural traits and not opportunistic responses of a flexible developmental programme. CONCLUSIONS This is the oldest direct evidence for a rooting system preserved in growth position. These rooting systems, which can be traced to a parent plant, include some of the earliest roots known to date and demonstrate that substantial plant-substrate interactions were under way by Early Devonian time. The morphological relationships between stems, root-bearing axes and roots corroborate evidence that positive gravitropism and root identity were evolutionarily uncoupled in lycophytes, and challenge the hypothesis that roots evolved from branches of the above-ground axial system, suggesting instead that lycophyte roots arose as a novel organ.
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Affiliation(s)
- Kelly K S Matsunaga
- Department of Biological Sciences, Humboldt State University, Arcata, CA, USA
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Tomescu AMF, Klymiuk AA, Matsunaga KKS, Bippus AC, Shelton GWK. Microbes and the Fossil Record: Selected Topics in Paleomicrobiology. THEIR WORLD: A DIVERSITY OF MICROBIAL ENVIRONMENTS 2016. [DOI: 10.1007/978-3-319-28071-4_3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Edwards D, Kenrick P. The early evolution of land plants, from fossils to genomics: a commentary on Lang (1937) 'On the plant-remains from the Downtonian of England and Wales'. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140343. [PMID: 25750238 PMCID: PMC4360123 DOI: 10.1098/rstb.2014.0343] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During the 1920s, the botanist W. H. Lang set out to collect and investigate some very unpromising fossils of uncertain affinity, which predated the known geological record of life on land. His discoveries led to a landmark publication in 1937, 'On the plant-remains from the Downtonian of England and Wales', in which he revealed a diversity of small fossil organisms of great simplicity that shed light on the nature of the earliest known land plants. These and subsequent discoveries have taken on new relevance as botanists seek to understand the plant genome and the early evolution of fundamental organ systems. Also, our developing knowledge of the composition of early land-based ecosystems and the interactions among their various components is contributing to our understanding of how life on land affects key Earth Systems (e.g. carbon cycle). The emerging paradigm is one of early life on land dominated by microbes, small bryophyte-like organisms and lichens. Collectively called cryptogamic covers, these are comparable with those that dominate certain ecosystems today. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.
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Affiliation(s)
- Dianne Edwards
- School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK
| | - Paul Kenrick
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Szövényi P, Frangedakis E, Ricca M, Quandt D, Wicke S, Langdale JA. Establishment of Anthoceros agrestis as a model species for studying the biology of hornworts. BMC PLANT BIOLOGY 2015; 15:98. [PMID: 25886741 PMCID: PMC4393856 DOI: 10.1186/s12870-015-0481-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/24/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants colonized terrestrial environments approximately 480 million years ago and have contributed significantly to the diversification of life on Earth. Phylogenetic analyses position a subset of charophyte algae as the sister group to land plants, and distinguish two land plant groups that diverged around 450 million years ago - the bryophytes and the vascular plants. Relationships between liverworts, mosses hornworts and vascular plants have proven difficult to resolve, and as such it is not clear which bryophyte lineage is the sister group to all other land plants and which is the sister to vascular plants. The lack of comparative molecular studies in representatives of all three lineages exacerbates this uncertainty. Such comparisons can be made between mosses and liverworts because representative model organisms are well established in these two bryophyte lineages. To date, however, a model hornwort species has not been available. RESULTS Here we report the establishment of Anthoceros agrestis as a model hornwort species for laboratory experiments. Axenic culture conditions for maintenance and vegetative propagation have been determined, and treatments for the induction of sexual reproduction and sporophyte development have been established. In addition, protocols have been developed for the extraction of DNA and RNA that is of a quality suitable for molecular analyses. Analysis of haploid-derived genome sequence data of two A. agrestis isolates revealed single nucleotide polymorphisms at multiple loci, and thus these two strains are suitable starting material for classical genetic and mapping experiments. CONCLUSIONS Methods and resources have been developed to enable A. agrestis to be used as a model species for developmental, molecular, genomic, and genetic studies. This advance provides an unprecedented opportunity to investigate the biology of hornworts.
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Affiliation(s)
- Péter Szövényi
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
- Institute of Systematic Botany, University of Zurich, Zurich, Switzerland.
- Swiss Institute of Bioinformatics, Quartier Sorge-Batiment Genopode, Lausanne, Switzerland.
- MTA-ELTE-MTM Ecology Research Group, ELTE, Biological Institute, Budapest, Hungary.
| | - Eftychios Frangedakis
- Department of Plant Sciences, University of Oxford, South Parks Rd, Oxford, UK.
- Current Address: Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113 0033, Japan.
| | - Mariana Ricca
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
- Swiss Institute of Bioinformatics, Quartier Sorge-Batiment Genopode, Lausanne, Switzerland.
| | - Dietmar Quandt
- Nees-Institut für Biodiversität der Pflanzen, University of Bonn, Meckenheimer Allee 170, D - 53115, Bonn, Germany.
| | - Susann Wicke
- Nees-Institut für Biodiversität der Pflanzen, University of Bonn, Meckenheimer Allee 170, D - 53115, Bonn, Germany.
- Institute for Evolution and Biodiversity, University of Muenster, Huefferstr. 1, 48149, Muenster, Germany.
| | - Jane A Langdale
- Department of Plant Sciences, University of Oxford, South Parks Rd, Oxford, UK.
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