scholarly journals Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants

2017 ◽  
Vol 373 (1739) ◽  
pp. 20170042 ◽  
Author(s):  
Alexander J. Hetherington ◽  
Liam Dolan
Keyword(s):  
Vascular Plants ◽  
Common Ancestor ◽  
Terrestrial Ecosystem ◽  
Bilateral Symmetry ◽  
Land Plant ◽  
Land Plants ◽  
Free Living ◽  
Rhynie Chert ◽  
The Common ◽  
Almost All

There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system—rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals Loss of plastid developmental genes coincides with a reversion to monoplastidy in hornworts

2022 ◽  
Author(s):  
Alexander Istvan MacLeod ◽  
Parth K Raval ◽  
Simon Stockhorst ◽  
Michael Knopp ◽  
Eftychios Frangedakis ◽  
...  
Keyword(s):  
Common Ancestor ◽  
Nuclear Division ◽  
Developmental Pathways ◽  
Ancestral State ◽  
Plastid Division ◽  
Plastid Development ◽  
State Reconstruction ◽  
Transcriptomic Data ◽  
The Common ◽  
Almost All

The first plastid evolved from an endosymbiotic cyanobacterium in the common ancestor of the Archaeplastida. The transformative steps from cyanobacterium to organelle included the transfer of control over developmental processes; a necessity for the host to orchestrate, for example, the fission of the organelle. The plastids of almost all embryophytes divide independent from nuclear division, leading to cells housing multiple plastids. Hornworts, however, are monoplastidic (or near-monoplastidic) and their photosynthetic organelles are a curious exception among embryophytes for reasons such as the occasional presence of pyrenoids. Here we screened genomic and transcriptomic data of eleven hornworts for components of plastid developmental pathways. We find intriguing differences among hornworts and specifically highlight that pathway components involved in regulating plastid development and biogenesis were differentially lost in this group of bryophytes. In combination with ancestral state reconstruction, our data suggest that hornworts have reverted back to a monoplastidic phenotype due to the combined loss of two plastid division-associated genes: ARC3 and FtsZ2.

scholarly journals O-methylated N-glycans Distinguish Mosses from Vascular Plants

Biomolecules ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 136
Author(s):  
David Stenitzer ◽  
Réka Mócsai ◽  
Harald Zechmeister ◽  
Ralf Reski ◽  
Eva L. Decker ◽  
...  
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Land Plants ◽  
Phylogenetic Relation ◽  
Complex Type ◽  
Animal Kingdom ◽  
Moss Species ◽  
First Finding ◽  
The Common ◽  
Terminal Mannose

In the animal kingdom, a stunning variety of N-glycan structures have emerged with phylogenetic specificities of various kinds. In the plant kingdom, however, N-glycosylation appears to be strictly conservative and uniform. From mosses to all kinds of gymno- and angiosperms, land plants mainly express structures with the common pentasaccharide core substituted with xylose, core α1,3-fucose, maybe terminal GlcNAc residues and Lewis A determinants. In contrast, green algae biosynthesise unique and unusual N-glycan structures with uncommon monosaccharides, a plethora of different structures and various kinds of O-methylation. Mosses, a group of plants that are separated by at least 400 million years of evolution from vascular plants, have hitherto been seen as harbouring an N-glycosylation machinery identical to that of vascular plants. To challenge this view, we analysed the N-glycomes of several moss species using MALDI-TOF/TOF, PGC-MS/MS and GC-MS. While all species contained the plant-typical heptasaccharide with no, one or two terminal GlcNAc residues (MMXF, MGnXF and GnGnXF, respectively), many species exhibited MS signals with 14.02 Da increments as characteristic for O-methylation. Throughout all analysed moss N-glycans, the level of methylation differed strongly even within the same family. In some species, methylated glycans dominated, while others had no methylation at all. GC-MS revealed the main glycan from Funaria hygrometrica to contain 2,6-O-methylated terminal mannose. Some mosses additionally presented very large, likewise methylated complex-type N-glycans. This first finding of the methylation of N-glycans in land plants mirrors the presumable phylogenetic relation of mosses to green algae, where the O-methylation of mannose and many other monosaccharides is a common trait.

scholarly journals Presence of three mycorrhizal genes in the common ancestor of land plants suggests a key role of mycorrhizas in the colonization of land by plants

2010 ◽  
Vol 186 (2) ◽  
pp. 514-525 ◽  
Author(s):  
Bin Wang ◽  
Li Huey Yeun ◽  
Jia-Yu Xue ◽  
Yang Liu ◽  
Jean-Michel Ané ◽  
...  
Keyword(s):  
Common Ancestor ◽  
Land Plants ◽  
The Common ◽  
Colonization Of Land

The Early Evolution of Land Plants

1986 ◽  
Vol 15 ◽  
pp. 45-63 ◽  
Author(s):  
A. H. Knoll ◽  
S. W. F. Grant ◽  
J. W. Tsao
Keyword(s):  
Plant Species ◽  
Vascular Plants ◽  
Vascular Plant ◽  
Terrestrial Ecosystem ◽  
Early Evolution ◽  
Land Plants ◽  
Ecological Diversity ◽  
Earth History ◽  
Standing Biomass ◽  
Terrestrial Life

Vascular plants are the most conspicuous organisms on Earth, accounting for some 97 % of our planet's standing biomass. The nearly 300,000 extant vascular plant species exhibit tremendous morphological and ecological diversity. Along with the 20,000 or more species of bryophytes, algae, lichens, and cyanobacteria that also live on land, they fuel a complex terrestrial ecosystem containing animals, fungi, protozoans, and bacteria. The richness of terrestrial life has evolved during the last 10 % of Earth history; there is no evidence for non-microbial land plants or animals in rocks older than the mid-Ordovician.

scholarly journals Palaeoecology and palaeophytogeography of the Rhynie chert plants: further evidence from integrated analysis of in situ and dispersed spores

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160491 ◽  
Author(s):  
Charles H. Wellman
Keyword(s):  
Hot Springs ◽  
Terrestrial Ecosystem ◽  
Land Plants ◽  
Integrated Analysis ◽  
Exceptional Preservation ◽  
Rhynie Chert ◽  
Floodplain Deposits ◽  
Early Land

The remarkably preserved Rhynie chert plants remain pivotal to our understanding of early land plants. The extraordinary anatomical detail they preserve is a consequence of exceptional preservation, by silicification, in the hot-springs environment they inhabited. However, this has prompted questions as to just how typical of early land plants the Rhynie chert plants really are. Some have suggested that they were highly adapted to the unusual hot-springs environment and are unrepresentative of ‘normal’ plants of the regional flora. New quantitative analysis of dispersed spore assemblages from the stratigraphical sequence of the Rhynie outlier, coupled with characterization of the in situ spores of the Rhynie chert plants, permits investigation of their palaeoecology and palaeophytogeography. It is shown that the Rhynie inland intermontane basin harboured a relatively diverse flora with only a small proportion of these plants actually inhabiting the hot-springs environment. However, the flora of the Rhynie basin differed from coeval lowland floodplain deposits on the same continent, as it was less diverse, lacked some important spore groups and contained some unique elements. At least some of the Rhynie plants (e.g. Horneophyton lignieri ) existed outside the hot-springs environment, inhabiting the wider basin, and were indeed palaeogeographically widespread. They probably existed in the hot-springs environment because they were preadapted to this unstable and harsh setting. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160489 ◽  
Author(s):  
Dianne Edwards ◽  
Paul Kenrick ◽  
Liam Dolan
Keyword(s):  
Terrestrial Ecosystem ◽  
Analytical Techniques ◽  
Land Plant ◽  
Life Cycles ◽  
Systems Science ◽  
Developmental Genetics ◽  
Earth Systems ◽  
Plant Life ◽  
Rhynie Chert ◽  
Tissue Systems

The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

scholarly journals The microfossil record of early land plants

2000 ◽  
Vol 355 (1398) ◽  
pp. 717-732 ◽  
Author(s):  
Charles H. Wellman ◽  
Jane Gray
Keyword(s):  
Fossil Record ◽  
Vascular Plants ◽  
Major Change ◽  
Land Plant ◽  
Land Plants ◽  
Early Land Plant ◽  
Early Late ◽  
Early Land ◽  
Lines Of Evidence ◽  
Plant Microfossil

Dispersed microfossils (spores and phytodebris) provide the earliest evidence for land plants. They are first reported from the Llanvirn (Mid–Ordovician). More or less identical assemblages occur from the Llanvirn (Mid–Ordovician) to the late Llandovery (Early Silurian), suggesting a period of relative stasis some 40 Myr in duration. Various lines of evidence suggest that these early dispersed microfossils derive from parent plants that were bryophyte–like if not in fact bryophytes. In the late Llandovery (late Early Silurian) there was a major change in the nature of dispersed spore assemblages as the separated products of dyads (hilate monads) and tetrads (trilete spores) became relatively abundant. The inception of trilete spores probably represents the appearance of vascular plants or their immediate progenitors. A little later in time, in the Wenlock (early Late Silurian), the earliest unequivocal land plant megafossils occur. They are represented by rhyniophytoids. It is only from the Late Silurian onwards that the microfossil / megafossil record can be integrated and utilized in interpretation of the flora. Dispersed microfossils are preserved in vast numbers, in a variety of environments, and have a reasonable spatial and temporal fossil record. The fossil record of plant megafossils by comparison is poor and biased, with only a dozen or so known pre–Devonian assemblages. In this paper, the early land plant microfossil record, and its interpretation, are reviewed. New discoveries, novel techniques and fresh lines of inquiry are outlined and discussed.

scholarly journals Juvenile hormone III skipped bisepoxide is widespread in true bugs (Hemiptera: Heteroptera)

2021 ◽  
Vol 8 (2) ◽  
pp. 202242
Author(s):  
Keiji Matsumoto ◽  
Toyomi Kotaki ◽  
Hideharu Numata ◽  
Tetsuro Shinada ◽  
Shin G. Goto
Keyword(s):  
Juvenile Hormone ◽  
Common Ancestor ◽  
Ultra Performance Liquid Chromatography ◽  
Insect Development ◽  
Methyl Farnesoate ◽  
True Bugs ◽  
Focal Species ◽  
Chemically Modified ◽  
The Common ◽  
Almost All

Juvenile hormone (JH) plays important roles in almost every aspect of insect development and reproduction. JHs are a group of acyclic sesquiterpenoids, and their farnesol backbone has been chemically modified to generate a homologous series of hormones in some insect lineages. JH III (methyl farnesoate, 10,11-epoxide) is the most common JH in insects, but Lepidoptera (butterflies and moths) and ‘higher’ Diptera (suborder: Brachycera; flies) have developed their own unique JHs. Although JH was first proposed in the hemipteran suborder Heteroptera (true bugs), the chemical identity of the heteropteran JH was only recently determined. Furthermore, recent studies revealed the presence of a novel JH, JH III skipped bisepoxide (JHSB 3 ), in some heteropterans, but its taxonomic distribution remains largely unknown. In the present study, we investigated JHSB 3 production in 31 heteropteran species, covering almost all heteropteran lineages, through ultra-performance liquid chromatography coupled with tandem mass spectrometry. We found that all of the focal species produced JHSB 3 , indicating that JHSB 3 is widespread in heteropteran bugs and the evolutionary occurrence of JHSB 3 ascends to the common ancestor of Heteroptera.

Molecular signatures of kerogens and bitumens from the Lower Devonian Rhynie chert: Insights into the botanical affinity of the earliest land plants

2020 ◽  
Author(s):  
Anuradha Tewari ◽  
Kevin Lepot ◽  
Suryendu Dutta ◽  
Borja Cascales-Miñana ◽  
Armelle Riboulleau
Keyword(s):  
Lower Devonian ◽  
Methyl Esters ◽  
Extraction Procedure ◽  
Terrestrial Ecosystem ◽  
Lignin Biosynthesis ◽  
Terrestrial Ecosystems ◽  
Land Plants ◽  
Molecular Signature ◽  
Acid Methyl ◽  
Rhynie Chert

<p>The Lower Devonian Rhynie chert of Scotland is an iconic geological formation that preserves the earliest known terrestrial ecosystem. This assemblage contains key evidence of earliest lineages of land plants, e.g., protracheophytes and paratracheophytes (former Rhyniaceae), together with animals, fungi, algae, and bacteria (Edwards et al., 2017). The exquisite preservation of this early biota provides an ideal scenario to explore the basal evolution of the land biosphere.</p><p>The Rhynie chert has been vastly studied from multiple viewpoints, however, the biomolecular composition, i.e., “molecular signature”, of the Rhynie flora, including the early detection of fossil lignin, remains clearly unresolved. Lignin biosynthesis has been considered as one of the crucial influences behind the survival and proliferation of land plants in terrestrial ecosystems. Here, we characterize the molecular fossils to help decipher the botanical affinities of the Rhynie flora.</p><p>Kerogens were isolated by the standard HF/HCl extraction procedure, and bitumens were extracted from the kerogens using organic solvents. The bitumens were studied with GC-MS, and the kerogens were analysed using Py-GC-MS and Py-GC×GC–TOFMS in the presence of TMAH reagent. The bitumens are characterized mainly by some aliphatic compounds such as a series of <em>n</em>-alkanes, pristane, phytane, and a series of diterpanes in very low abundance, as well as a set of aromatic compounds such as naphthalene and methylnaphthalenes, phenanthrene and methylphenanthrenes and retene. The pyrolysates, obtained using Py-GC-MS are dominated by benzene and methyl benzenes, phenol and methylphenols, Polycyclic Aromatic Hydrocarbons (PAHs) like naphthalene and methylnaphthalenes, phenanthrene and methylphenanthrenes, anthracene and methylanthracene, fluoranthene, pyrene, etc. Series of fatty acid methyl esters (FAME) and of <em>n</em>-alkane/alkene doublets were also detected. The thermochemolysates acquired from Py-GC×GC–TOFMS include the same compounds; additional methoxybenzene derivatives, methoxy toluene, methoxy benzaldehydes, and benzoic acid methyl esters, generated by reaction with TMAH, were also identified. Phenols and methoxybenzenes in the pyrolysates and thermochemolysates originate from lignin, and this is the first time that lignin monomers are formally identified from Rhynie chert samples.</p><p><strong>References:</strong></p><p>Edwards, D., Kenrick, P., Dolan, L., 2017. History and contemporary significance of the Rhynie cherts—our earliest preserved terrestrial ecosystem. Philosophical Transactions B Royal Society 373: 20160489.</p>

scholarly journals Fungi and fungal interactions in the Rhynie chert: a review of the evidence, with the description of Perexiflasca tayloriana gen. et sp. nov. †

2017 ◽  
Vol 373 (1739) ◽  
pp. 20160500 ◽  
Author(s):  
Michael Krings ◽  
Carla J. Harper ◽  
Edith L. Taylor
Keyword(s):  
Three Dimensional ◽  
Terrestrial Ecosystem ◽  
Land Plant ◽  
Biological Degradation ◽  
Microbial Life ◽  
Plant Parts ◽  
Comprehensive Information ◽  
Rhynie Chert ◽  
Fungal Associations ◽  
Fungal Interactions

The Lower Devonian Rhynie chert is one of the most important rock deposits yielding comprehensive information on early continental plant, animal and microbial life. Fungi are especially abundant among the microbial remains, and include representatives of all major fungal lineages except Basidiomycota. This paper surveys the evidence assembled to date of fungal hyphae, mycelial cords and reproductive units (e.g. spores, sporangia, sporocarps), and presents examples of fungal associations and interactions with land plants, other fungi, algae, cyanobacteria and animals from the Rhynie chert. Moreover, a small, chytrid-like organism that occurs singly, in chain-like, linear arrangements, planar assemblages and three-dimensional aggregates of less than 10 to individuals in degrading land plant tissue in the Rhynie chert is formally described, and the name Perexiflasca tayloriana proposed for the organism. Perexiflasca tayloriana probably colonized senescent or atrophied plant parts and participated in the process of biological degradation. The fungal fossils described to date from the Rhynie chert constitute the largest body of structurally preserved evidence of fungi and fungal interactions from any rock deposit, and strongly suggest that fungi played important roles in the functioning of the Early Devonian Rhynie ecosystem. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

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