The origin and early evolution of land plants in the mid-Palaeozoic era, between about 480 and 360 million years ago, was an important event in the history of life, with far-reaching consequences for the evolution of terrestrial organisms and global environments. A recent surge of interest, catalysed by palaeobotanical discoveries and advances in the systematics of living plants, provides a revised perspective on the evolution of early land plants and suggests new directions for future research.

/pdf/the-origin-and-early-evolution-of-plants-on-land-25o6hryi4f.pdf

The origin and early evolution of plants on land

Reconstructing the origin and evolution of land plants and their algal relatives is a fundamental problem in plant phylogenetics, and is essential for understanding how critical adaptations arose, including the embryo, vascular tissue, seeds, and flowers. Despite advances in molecular systematics, some hypotheses of relationships remain weakly resolved. Inferring deep phylogenies with bouts of rapid diversification can be problematic; however, genome-scale data should significantly increase the number of informative characters for analyses. Recent phylogenomic reconstructions focused on the major divergences of plants have resulted in promising but inconsistent results. One limitation is sparse taxon sampling, likely resulting from the difficulty and cost of data generation. To address this limitation, transcriptome data for 92 streptophyte taxa were generated and analyzed along with 11 published plant genome sequences. Phylogenetic reconstructions were conducted using up to 852 nuclear genes and 1,701,170 aligned sites. Sixty-nine analyses were performed to test the robustness of phylogenetic inferences to permutations of the data matrix or to phylogenetic method, including supermatrix, supertree, and coalescent-based approaches, maximum-likelihood and Bayesian methods, partitioned and unpartitioned analyses, and amino acid versus DNA alignments. Among other results, we find robust support for a sister-group relationship between land plants and one group of streptophyte green algae, the Zygnematophyceae. Strong and robust support for a clade comprising liverworts and mosses is inconsistent with a widely accepted view of early land plant evolution, and suggests that phylogenetic hypotheses used to understand the evolution of fundamental plant traits should be reevaluated.

/pdf/phylotranscriptomic-analysis-of-the-origin-and-early-4cs38v80rr.pdf

Phylotranscriptomic analysis of the origin and early diversification of land plants

http://www.noahwhiteman.org/uploads/7/1/3/1/7131048/trplsc952.pdf

Evolution of jasmonate and salicylate signal crosstalk.

Although macroscopic plants, animals, and fungi are the most familiar eukaryotes, the bulk of eukaryotic diversity is microbial. Elucidating the timing of diversification among the more than 70 lineages is key to understanding the evolution of eukaryotes. Here, we use taxon-rich multigene data combined with diverse fossils and a relaxed molecular clock framework to estimate the timing of the last common ancestor of extant eukaryotes and the divergence of major clades. Overall, these analyses suggest that the last common ancestor lived between 1866 and 1679 Ma, consistent with the earliest microfossils interpreted with confidence as eukaryotic. During this interval, the Earth's surface differed markedly from today; for example, the oceans were incompletely ventilated, with ferruginous and, after about 1800 Ma, sulfidic water masses commonly lying beneath moderately oxygenated surface waters. Our time estimates also indicate that the major clades of eukaryotes diverged before 1000 Ma, with most or all probably diverging before 1200 Ma. Fossils, however, suggest that diversity within major extant clades expanded later, beginning about 800 Ma, when the oceans began their transition to a more modern chemical state. In combination, paleontological and molecular approaches indicate that long stems preceded diversification in the major eukaryotic lineages.

/pdf/estimating-the-timing-of-early-eukaryotic-diversification-10j7axrrzp.pdf

Estimating the timing of early eukaryotic diversification with multigene molecular clocks

The East African rift system

Late Devonian plants from Australia: the anatomically preserved flora from Barraba, New South Wales.

About ten specimens of Dawsonites magnus sp. nov. have been discovered in the Lower Devonian (Upper Pragian) of Ensival (southern margin of the Verviers Synclinorium, Belgium). The plant is made of slightly longitudinally ridged, isotomously branched axes. The large fusiform paried sporangia are borne at the distal extremity of the axes. This new species is compared with the other species of Dawsonites. This artificial genus, which contains, amond others, fertile detached axes of several Trimerophytopsida, is proved to be still useful

Dawsonites magnus sp. nov., une plante nouvelle du Dévonien inférieur d'Ensival (Belgique).

Pachytheca, une algue probable, a ete recolte dans des affleurements a Nonceveux et au bord du lac de La Gileppe. Sur base palynologique, Nonceveux est rapporte au Gedinnien (?=Lochkovien) superieur, tandis que La Gileppe va du Gedinnien (?=Lochkovien) superieur au Siegenien (?=Praguien) inferieur. Des images en microscopie optique et electronique a balayage de la structure interne de la plante sont proposees. Prototaxites et un organisme morphologiquement proche de Pachytheca sont egalement illustres.

https://popups.ulg.ac.be/0037-9395/index.php?id=1301&file=1&pid=1298

Philippe Gerrienne

Papers

Late Devonian plants from Australia: the anatomically preserved flora from Barraba, New South Wales.

Dawsonites magnus sp. nov., une plante nouvelle du Dévonien inférieur d'Ensival (Belgique).

Les Pachytheca de La Gileppe et de Nonceveux (Dévonien inferieur de Belgique)

Psilophytites gileppensis nov. sp.,une plante épineuse du Dévonien inférieur du bord sud du synclinorium de Verviers (Belgique)

Givetian megaspores from Libya and Belgium