Laminariales was also late to emerge in the BACR, branching from its sister Chordales in the early Cenozoic. J. Phycol. Analysis of the evolutionary processes driving these transitions remains a productive area of research for the brown algae. This new literature survey indicated marked intraspecific reproductive system variability at the population level. stramenopiles), one of four major groups in the eukaryotic lineage containing Telonemea, Stramenopiles, Alveolata, and Rhizaria … Rather, Fucales form important habitats in these areas. Interestingly, other brown algae with more marked morphological differences between sexes had only a small fraction of sex-biased genes, ca. (2019), Kim et al. The Arctic basin began as an embayment of the Pacific Ocean until this connection was severed approximately 66 Ma (Lawver et al., 1990; Marincovich et al., 1990). In the broader context of eukaryotic evolution, brown algae originated within the heterokonts (i.e. The sea lettuce, Ulva, belongs here. We also review evidence … Thus, within-species variation for brown algal life cycles occurs in nature, as in red seaweeds (Destombe et al., 1989). Climate change and increased micro- and macronutrients due to pollution are likely playing a role in the massive increase in biomass and movement of Sargassum around the Atlantic (Louime et al., 2017). Fucales is a large order of more than 500 species and 9 families, members of which are major components of coastal ecosystems globally, including cold water regions of the Northern (Fucus, Ascophyllum, Pelvetiopsis, Silvetia, etc.) We conclude our review by providing perspectives on promising avenues for studying brown algal evolution, opened up by the availability of genomic data. We also review brown algal speciation mechanisms and the associated biogeographic patterns that have emerged globally. In contrast, Stschapovia and Platysiphon appear to show a modified life history without alternation between two different generations, as in Ascoseirales and Fucales. Notable examples of species introduced by transport vectors (e.g. By comparison with other groups, like embryophytes, the incidence of polyploidy is poorly understood in brown algae. The green lineage (Viridiplantae) comprises the green algae and their descendants the land plants, and is one of the major groups of oxygenic photosynthetic eukaryotes. The evolutionary processes that produced the Archaeplastida and secondary algal lineages remain under investigation (2 ⇓ ⇓ –5), but it is clear that both nuclear and plastid genes from the ancestral red algae have contributed dramatically to broader eukaryotic evolution and diversity. Perhaps the clearest example of a brown alga adapted for polar conditions, the Arctic kelp Laminaria solidungula is known to complete all of its growth under ice during months of darkness, using the summer months exclusively for carbon storage (Dunton and Schell, 1986). Figure 5. The nonrecombining sex-determining regions (SDR) of the U and V chromosomes are ∼1 Mbp in length, occupying about a 10th of the sex chromosome (Cormier et al., 2017). Hypotheses explaining diversification of the BACR at the ordinal level are otherwise scant. Molecular phylogenetic studies conclude that bryophytes are the earliest diverging lineages of the extant land plants. An important initiative for the future is the Phaeoexplorer project (led by Roscoff Biological Station and Genoscope), which aims to provide 67 annotated genome assemblies of 47 brown algal species, plus four related unicellular and multicellular Ochrophyta. Many species are projected to retreat toward higher latitudes with the movement of isotherms (Assis, Araújo, et al., 2018; Martínez et al., 2018), and the loss of unique genetic diversity (Nicastro et al., 2013; Neiva et al., 2015; Assis, Araújo, et al., 2018) and functional diversity (Pereira et al., 2015; Mota et al., 2018) at retreating rear-edges is a concern. For example, Upper Devonian species Drydenia foliata, Hungerfordia dichotoma, and Enfieldia mutilata (380–360 Ma; Fry and Banks, 1955), and the Late Pennsylvanian-Early Permian genus Perissothallus (300 Ma; Krings et al., 2007) are fossil specimens variously linked to extant brown, green, and red algal species. While these species can be easily distinguished based on morphology and variability in the rbcL plastid locus, no nucleotide polymorphisms exist between these species in the LSU rRNA gene, suggesting that speciation of these two entities nonetheless occurred recently in evolutionary time (McCauley and Wehr, 2007). Wild type individuals produce an extensive network of basal filaments before producing upright (apical) filaments, whereas the imm mutant only produces a small rhizoid and the dis mutant completely lacks basal tissues. F. Leliaert et al., “Phylogeny and molecular evolution of the green algae,” CRITICAL REVIEWS IN PLANT SCIENCES, vol. Although these data have helped resolve the phylogeny of numerous clades (e.g., green algae, angiosperms, and gymnosperms), their utility for inferring relationships across all green plants is uncertain. To date, brown algal evolution has been investigated almost exclusively in a genetic framework, but epigenetic processes (i.e. Current hypotheses posit the early divergence of two discrete clades from an . Taken together, therefore, analysis of the dis and imm mutants has indicated that evolution of the sporophyte and gametophyte developmental programs has involved both sharing of genetic components (DIS) and the evolution of generation-specific programs (IMM). The BACR contains the most ecologically and economically important orders, including the Fucales and Laminariales. Are homologies in vertebrate sex determination due to shared ancestry or to limited options? Topological conflicts with bayesian trees are indicated by an *. Morphology and life history patterns are diverse among families, although all members show heteromorphic life histories with annual, large parenchymatous sporophytes and minute filamentous gametophytes. Moreover, the PAR is enriched in genes that are preferentially or exclusively expressed during the sporophyte (diploid) generation of the life cycle, and many of these genes do not have homologs in other brown algal clades (Luthringer et al., 2015). Alone or in concert, variations in reproductive phenology, niche occupancy, and mating system can be strong segregating factors. Biotic interactions have also been invoked to explain the limited diversity and dominance of tropical brown algae. Registered in England & Wales No. Genetic surveys have nonetheless revealed surprising levels of diversity unique to the Arctic basin (Saunders and McDevit, 2013; Laughinghouse et al., 2015; Küpper et al., 2016; Bringloe et al., 2020), a finding difficult to reconcile with the historical view of Arctic populations as extensions of temperate species (Lee, 1973), a simple depiction perhaps further justified by the dull character of Arctic seaweeds. This review summarizes our current understanding of organelle genome evolution in the green algae, genomic insights into the ecology of oceanic picoplanktonic prasinophytes, molecular mechanisms … Mating system variation within species has been widely reported in land plants, where it is due to environmental and genetic factors (Goodwillie et al., 2005). Based on recent advances, work in this area is expected to uncover both examples of deep conservation of some regulatory mechanisms (such as the involvement of TALE HD TFs in life cycle regulation for example; Arun et al., 2019) and lineage-specific novelties (such as the EsV-1-7 domain family, for example, which is absent from both plants and animals; Macaisne et al., 2017). The life cycles of Fucales are oogamous with oogonia and spermatangia borne on specialized branches known as receptacles. The red algae are distinguishable among eukaryotic lineages by a combination of biochemical and ultrastructural features, some of which they share with Glaucophyta and Cyanobacteria. Similarly, recent phylogeographic analyses of both the Laminariales (Starko et al., 2019) and the genus Sargassum (Yip et al., 2020) indicate that region-specific diversification is likely a common process. @article{3098864, abstract = {The green lineage (Viridiplantae) comprises the green algae and their descendants the land plants, and is one of the major groups of oxygenic photosynthetic eukaryotes. It should also be noted that time calibration of the brown algal phylogeny is based on limited fossil records. Natural populations of brown algae reproduce sexually by external fertilization (broadcast spawning; e.g., many Fucoids, Ectocarpales and Dictyotales) or functional brooding (i.e., retention of fertilized eggs, e.g., Sargassaceae). evolution of green algae and photosynthetic processes, particu-larly for Rubisco during the transition to terrestrial plant life forms. Most other freshwater brown algae are from the Sphacelariales, all of which are obligate freshwater inhabitants (Sheath and Wehr, 2015). Academia.edu no longer supports Internet Explorer. Moreover, intraspecific lineage differentiation and, in some cases, true speciation events have been known to occur over local environmental gradients such as tidal height, depth, and wave exposure (e.g. In Saccharina latissima, NW Atlantic and Pacific lineages reveal remarkable genetic integrity in a large zone of high-Arctic secondary contact, suggestive of reproductive isolation and incipient speciation (Neiva et al., 2018). Figure 2. Although most lineages of large habitat forming algae (e.g., Fucaceae, Laminariales, Durvilliaceae) are generally absent from tropical regions, the genus Sargassum is a notable exception with more than 350 currently recognized species (Yip et al., 2020). The first description of a freshwater brown alga was Pleurocladia lacustris (Braun, 1855), a widely distributed member of the Ectocarpales. Red and green macroalgal lineages were also present alongside the brown algae, leading to confusion and debate as to how to classify fossil specimens with simple and convergent features. Although allopatric speciation arising from geological and climatic processes is likely to have been an important process in establishing the modern diversity and distribution of brown algal species across modern oceans, there are many examples of brown algal speciation that did not depend on strict geographical isolation. Diversity is highly skewed toward Sargassaceae, which comprises ca. In the sister species Postelsia palmaeformis and Nereocystis luetkeana, the difference in potential for long distance dispersal is dramatic, in that P. palmaeformis is characterized by drooping, deeply grooved blades, promoting highly localized dispersal and selfing (Barner et al., 2011), while N. luetkeana produces dehiscent sori on blades near the surface- up to tens of meters from the substratum, presumably promoting greater dispersal distances (Dayton, 1985). Neiva et al., 2017) have been recognized as important areas where relict populations (and gene-pools) persevere (Assis, Araújo, et al., 2018). In contrast, areas colonized only post-glacially (e.g. HMG domain genes are involved in sex determination in animals and mating type determination in fungi (Idnurm et al., 2008; Graves and Peichel, 2010). and Southern Hemisphere (Durvillaea, Cystophora, etc. Modern molecular phylogenetic 5 Howick Place | London | SW1P 1WG. A multi-marker phylogeny of the brown algae was built from 10 mitochondrial, plastid and nuclear loci (>10,000 nt) of 72 phaeophycean taxa, resulting in trees with well-resolved inter-ordinal relationships within the BACR. The asterisk represents the ancestral node of the majority of the SI clade, dated to the late Paleozoic (∼310 Ma; Brown and Sorhannus, 2010). Brown macroalgae exhibit a wide variety of life cycles, sexual systems, and reproductive modes (for a recent review see Liu et al., 2017). Calibrated phylogenies, although admittedly based on limited fossil evidence, have also provided insight into the timescales of brown algal evolution. There is substantial evidence that geographical isolation has played a major role in patterns of speciation and diversification across various brown algal clades. The recent confirmation of two late-Pleistocene allopolyploid lineages in the fucoid genus Pelvetiopsis are unique thus far, remarkably involving the same extant paternal ancestor (Neiva et al., 2017; Sousa et al., 2019). However, current genome data do not support hypotheses of ancient polyploidy, at least for Laminariales and Ectocarpales (Cock et al., 2010; Ye et al., 2015; Nishitsuji et al., 2016; 2019; Dittami et al., 2020; Shan et al., 2020). While DNA barcoding has been an immensely successful tool for understanding species diversity within the brown algae, this method reflects the evolutionary history of the organelles themselves and not necessarily that of the host species, especially given the relatively recent evolution of brown algae in comparison to green and red algae. Northeast Pacific; Chan, 2018). South Africa, but see Martínez et al., 2018 for an Australian study), semi-enclosed, longitudinally oriented seas (e.g. To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to upgrade your browser. Ascoseirales is a monotypic order featuring the Antarctic species Ascoseira mirabilis, which forms a large parenchymatous thallus with intercalary growth, holdfast and stipe, and is characterized by a diplontic life cycle, a feature that appears in only one other brown algal order, the Fucales. Recently developed genetic tools provide the means to address this problem by identifying genes associated with specific biological processes. This energy input plays an important role in maintaining food security for many large mammals (Estes et al., 2016; Pyenson and Vermeij, 2016; Vermeij et al., 2019), including humans, and is believed to have facilitated the spread of human populations from Asia to North America prior to the Holocene, the so-called “kelp highway” hypothesis (Erlandson et al., 2015; Braje et al., 2017). 44, 467–477. Evolution of life history traits and sexual reproduction, IV. The evolution of land plants from a green algal ancestor Specifically, haploidy could be favored if there is little mixing (i.e., crossing) with diploids (Otto and Marks, 1996). The thicker lines are roughly proportional to the species numbers in the clades (the clades with <500 species are drawn with thin lines). To demonstrate the usefulness of this novel perspective on red algal phylogeny, we used the reference tree to elucidate the evolution of the isopentenyl pyrophosphate (IPP) biosynthetic pathway. We conclude our review by discussing promising avenues for future research opened by genomic datasets, directions that are expected to reveal critical insights into brown algal evolution in past, present, and future oceans. The evolution of hydrophobic cell wall biopolymers: from algae to angiosperms J Exp Bot . The sister orders Ectocarpales and Asterocladales emerged late within the BACR, close to the end of the Cretaceous period (66 Ma), with markedly different outcomes in species diversity. Phylogeny and evolution of charophytic algae and land plants. Mesostigma is a single-celled flagellate that branches off early in the phylogenetic tree of streptophytes, so it is generally assumed that multicellularity was acquired during subsequent evolution of the streptophyte lineage. Genetic divergence correlates with morphological and ecological subdivision in the deep‐water elk kelp, European seaweeds under pressure: consequences for communities and ecosystem functioning, Site and nature of calcium carbonate deposits in a calcareous brown alga. High densities of individuals are also likely important because pheromone gradients for sperm attraction are effective only at mm scales (Lüning and Müller, 1978). The multilocus phylogenetic approach of Cánovas et al., (2011) showed that hermaphroditism is a derived trait and that the hermaphrodite lineage (F. spiralis and relatives) forms a paraphyletic sister clade with the ancestral extant southern populations of dioecious Fucus vesiculosus. compare to other algae its the only one that contains chlorophyll "b" which it helps it facilitate photosynthesis among in taking light waves. Sex-specific homeodomain proteins Sxi1alpha and Sxi2a coordinately regulate sexual development in, Flow visualization around single- and multiple-bladed seaweeds with various morphologies, Identification of the sex genes in an early diverged fungus, Cooler winters as a possible cause of mass extinctions at the Eocene/Oligocene boundary, Kelp transcriptomes provide robust support for interfamilial relationships and revision of the little known Arthrothamnaceae (Laminariales), Multifidene and aucantene, C11 hydrocarbons in the male-attracting essential oil from the gynogametes of, High temperatures in the Late Cretaceous Arctic Ocean, Maintenance of dynamic strain similarity and environmental stress factor in different flow habitats: thallus allometry and material properties of a giant kelp, Proceedings of the 13th International Coral Reef Symposium, Molecular phylogeny of the brown algal genera, Morphology, life history, and molecular phylogeny of, The specific identity and life history of Japanese, Ancestral reproductive structure in basal kelp. In the gametophyte, asymmetric division of the initial cell, a meiospore, leads to the production of a small rhizoid and an upright filament that will develop into the apical thallus. Sorry, preview is currently unavailable. Brown algae vary widely in traits that influence their potential for speciation and diversification, such as life history strategies, dispersal mechanisms and potential, as well as apparent scope for ecological diversification. Chordales is a small order, sister to the Laminariales, with nine known species in three genera and three families distributed in temperate to cold-water regions of the Northern Hemisphere. Ancestral state reconstruction subsequently revealed several characters unique to the Chordales (simple kelps), rather than ancestral to the Laminariales (complex kelps) as originally supposed. Kelp growth is mediated by an intercalary meristem that is in the transition between stipe and lamina, allowing the development of perennial sporophytes. They display isomorphic life histories with various types of sexual reproduction including isogamy, anisogamy and oogamy (Figure 3). The impact of climate change on biogeographic distributions of brown algae will continue to be a hot topic in the near future. tropical taxa), or orders that have converged on similar ecological roles (i.e. The PAR of the Ectocarpus sex chromosome recombines at a similar rate to the autosomes (Luthringer et al., 2015). Along with other multicellular groups such as metazoans, fungi and green plants, brown algae possess several key characteristics that have enabled them to thrive as macroscopic organisms (Charrier et al., 2008), including cell-to-cell adhesion and communication (Charrier et al., 2008; Cock et al., 2010; 2014; Deniaud-Bouët et al., 2014), tissue differentiation (Fritsch, 1935; Kloareg and Quatrano, 1988), internal transport of sugars (Fritsch, 1935; Schmitz and Srivastava, 1976) and the capacity for three dimensional growth (Fritsch, 1935; Starko and Martone, 2016a). directional selection) during range expansions and pulse disturbance events would provide important context for current trends. Using Bayesian relaxed molecular clock analysis, it is shown that the BACR is likely to represent a gradual diversification spanning most of the Lower Cretaceous rather than a …
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