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Symbiotic options for the conquest of land

2015; Elsevier BV; Volume: 30; Issue: 8 Linguagem: Inglês

10.1016/j.tree.2015.05.007

1872-8383

Katie J. Field, Silvia Pressel, Jeffrey G. Duckett, William R. Rimington, Martin I. Bidartondo,

Plant and animal studies

•Plant terrestrialization involved establishing mutualisms with fungi over 450 Mya. •The discovery of an ancient symbiosis challenges a decades-old paradigm. •Function, signaling, and regulation of plant–microbe symbioses are being unraveled. •Conquering land relied on a variety of symbiotic strategies still at work today. The domination of the landmasses of Earth by plants starting during the Ordovician Period drastically altered the development of the biosphere and the composition of the atmosphere, with far-reaching consequences for all life ever since. It is widely thought that symbiotic soil fungi facilitated the colonization of the terrestrial environment by plants. However, recent discoveries in molecular ecology, physiology, cytology, and paleontology have brought into question the hitherto-assumed identity and biology of the fungi engaged in symbiosis with the earliest-diverging lineages of extant land plants. Here, we reconsider the existing paradigm and show that the symbiotic options available to the first plants emerging onto the land were more varied than previously thought. The domination of the landmasses of Earth by plants starting during the Ordovician Period drastically altered the development of the biosphere and the composition of the atmosphere, with far-reaching consequences for all life ever since. It is widely thought that symbiotic soil fungi facilitated the colonization of the terrestrial environment by plants. However, recent discoveries in molecular ecology, physiology, cytology, and paleontology have brought into question the hitherto-assumed identity and biology of the fungi engaged in symbiosis with the earliest-diverging lineages of extant land plants. Here, we reconsider the existing paradigm and show that the symbiotic options available to the first plants emerging onto the land were more varied than previously thought. members of the phylum Glomeromycota that form cell-to-cell nutritional associations with plant roots and extend filaments into soil to forage for minerals, colonize other roots, and form spores. They often produce characteristic highly branched tree-like structures, known as arbuscules, within colonized plant cells. an organism nutritionally dependent on another living organism. refers to a multinucleate mass of cytoplasm, characteristic of nonseptate filamentous fungi. the volume of soil surrounding a root that becomes depleted of nutrients. plant in which the embryo is retained within maternal tissues, includes all clades of living land plants. typically cryptic and asymptomatic microbe living within a plant, or any microbe within or between intact fossilized plant cells. haploid stage in the alternation of generations during the life cycle of plants, it is dominant in nonvascular plants. a fungal phylum comprising biotrophs, including all known AM fungi and a mutualistic fungus of photosynthetic bacteria (i.e., Geosiphon). It includes the orders Archaeosporales, Paraglomerales, Diversisporales, and Glomerales. a fungal filament comprising tubular cells. a fungal subphylum of early-diverging fungal lineages comprising saprotrophs, parasites, and mutualists. It includes the orders Endogonales (pea truffles) and Mucorales (pin molds). a symbiosis that increases the fitness of all partners. ‘fungus root’, a typically mutualistic symbiosis between plant roots and fungi. ‘Mycorrhiza-like’ is used to refer to mutualistic fungal symbiosis in plants without true roots. land plants without true (i.e., lignin-containing) vascular tissue, also known as bryophytes. They include three phyla: Marchantiophyta (liverworts), Anthocerotophyta (hornworts), and Bryophyta (mosses). unicellular tubular extension of an epidermal plant cell into the substrate functioning in attachment and resource uptake. an organism that fulfills its nutritional needs from dead organic matter, a decomposer. diploid stage in the alternation of generations during the life cycle of plants. It is dominant in vascular plants. the living together of unlike organisms, sometimes restricted to persistent mutualisms. body of some plants and fungi that is not differentiated into organs. land plants with lignified vascular tissue (i.e., xylem), also known as tracheophytes. They include the phyla Lycopodiophyta (lycopods or club mosses), Pteridophyta (ferns and allies), Pinophyta (conifers), Cycadophyta (cycads), Ginkgophyta (Ginkgo), Gnetophyta (Gnetum, Welwitschia, and Ephedra), and Magnoliophyta (flowering plants or angiosperms).