Zygnematophyta

Hall, John D.; McCourt, Richard M.

doi:10.1007/978-3-319-28149-0_41

Cited by 3 publications

(2 citation statements)

References 85 publications

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“…Our robust phylogenetic framework of the zygnematophytes now enables comparisons of species in an evolutionary context, and assessment of evolutionary scenarios with greater confidence. It is remarkable that the majority of zygnematophycean species are unicellular [24], as most of their streptophyte relatives (Embryophyta, Coleochaetophyceae, Charophyceae, Klebsormidiophyceae, Chlorokybophyceae) display some kind of multicellularity, from sarcinoids to three-dimensional tissues [25]. However, some zygnematophycean lineages exhibit more developmental complexity such as the formation of filaments, sometimes even with rhizoids or branched cells [25, 26].…”

Section: Resultsmentioning

confidence: 99%

A phylogenomically informed five-order system for the closest relatives of land plants

Hess

Williams

Busch

et al. 2022

Preprint

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The evolution of streptophytes had a profound impact on life on Earth. They brought forth those photosynthetic eukaryotes that today dominate the macroscopic flora: the land plants (Embryophyta) [1]. There is convincing evidence that the unicellular/filamentous Zygnematophyceae--and not the morphologically more elaborate Coleochaetophyceae or Charophyceae--are the closest algal relatives of land plants [2, 3, 4, 5, 6]. Despite the species richness (>4,000), wide distribution, and key evolutionary position of the zygnematophytes, their internal phylogeny remains largely unresolved [7, 8]. There are also putative zygnematophytes with interesting body plan modifications (e.g., filamentous growth) whose phylogenetic affiliations remain unknown. Here, we studied a filamentous green alga (strain MZCH580) from an Austrian peat bog with central or parietal chloroplasts that lack discernible pyrenoids. It represents Mougeotiopsis calospora PALLA, an enigmatic alga that was described more than 120 years ago [9], but never subjected to molecular analyses. We generated transcriptomic data of M. calospora strain MZCH580, and conducted comprehensive phylogenomic analyses (326 nuclear loci) for 46 taxonomically diverse zygnematophytes. Strain MZCH580 falls in a deep-branching zygnematophycean clade together with some unicellular species, and thus represents a formerly unknown zygnematophycean lineage with filamentous growth. Our well-supported phylogenomic tree lets us propose a new five-order system for the Zygnematophyceae, and provides evidence for at least five independent origins of true filamentous growth in the closest algal relatives of land plants. This phylogeny provides a robust and comprehensive framework for performing comparative analyses and inferring the evolution of cellular traits and body plans in the closest relatives of land plants.

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Section: Resultsmentioning

confidence: 99%

A phylogenomically informed five-order system for the closest relatives of land plants

Hess

Williams

Busch

et al. 2022

Preprint

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“…These include zygospores with resistant walls that contain sporopollenin-like compounds (Delwiche et al 1989). Zygnema and related species also produce zygospores that are known in the fossil record (Hall and McCourt 2017). Thus, it appears that the perennation function provided by a resistant cell wall was transferred in evolution from the algal zygote to the spore wall.…”

Section: Introductionmentioning

confidence: 99%

An evo-devo perspective on no Ordovician land plants

Strother¹

2023

EJES

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Molecular phylogenetic studies of land plant (embryophyte) origins have begun to tease apart those evolutionary contributions derived from prior algal genes and those de novo genes that evolved during a charophyte-embryophyte transition. Applying the concept of genomic assembly in plant evolution to the fossil record leads to a paradigm shift in the interpretation of the Ordovician record of land plants. Traditional phylogenetic thinking requires fossil species taxa to occupy nodes on a phylogeny. An evo-devo approach can view character evolution separately from species taxa, freeing up fossil spores and tissue fragments to become clues to underlying developmental pathways or gene regulatory networks. This results in a re-assessment of what is meant by the presence of land plants in the Ordovician landscape. The new model helps to reconcile discrepancies between molecular time-trees and the "missing" record of fossil plants during the Ordovician Period. Integrating the Ordovician fossil record within an evo-devo modelBasically, an evo-devo model of the algal-plant transition considers genomic assembly as the underlying evolutionary process by which the transition occurred. The extent to which fossils can be tied to particular ChINs can, then, help to construct an

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The Arctic Cylindrocystis (Zygnematophyceae, Streptophyta) Green Algae are Genetically and Morphologically Diverse and Exhibit Effective Accumulation of Polyphosphate

Barcytė

Pilátová

Mojzeš

et al. 2019

Journal of Phycology

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The green algal genus Cylindrocystis is widespread in various types of environments, including extreme habitats. However, very little is known about its diversity, especially in polar regions. In the present study, we isolated seven new Cylindrocystis-like strains from terrestrial and freshwater habitats in Svalbard (High Arctic). We aimed to compare the new isolates on a molecular (rbcL and 18S rDNA), morphological (light and confocal laser scanning microscopy), and cytological (Raman microscopy) basis. Our results demonstrated that the Arctic Cylindrocystis were not of a monophyletic origin and that the studied strains clustered within two clades (tentatively named the soil and freshwater/glacier clades) and four separate lineages. Morphological data (cell size, shape, and chloroplast morphology) supported the presence of several distinct taxa among the new isolates. Moreover, the results showed that the Arctic Cylindrocystis strains were closely related to strains originating from the temperate zone, indicating high ecological versatility and successful long-distance dispersal of the genus. Large amounts of inorganic polyphosphate (polyP) grains were detected within the chloroplasts of the cultured Arctic Cylindrocystis strains, suggesting effective luxury uptake of phosphorus. Additionally, various intracellular structures were identified using Raman microscopy and cytochemical and fluorescent staining. This study represents the first attempt to combine molecular, morphological, ecological, and biogeographical data for Arctic Cylindrocystis. Our novel cytological observations partially explain the success of Cylindrocystis-like microalgae in polar regions.

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Zygnematophyta

Cited by 3 publications

References 85 publications

A phylogenomically informed five-order system for the closest relatives of land plants

A phylogenomically informed five-order system for the closest relatives of land plants

An evo-devo perspective on no Ordovician land plants

The Arctic Cylindrocystis (Zygnematophyceae, Streptophyta) Green Algae are Genetically and Morphologically Diverse and Exhibit Effective Accumulation of Polyphosphate

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