Fig 8 - uploaded by Ivan V. Zmitrovich
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1 The scheme of basidium (promycelium) morphogeny in the ustilaginaceous fungi according to Linder (1940). This scheme demonstrates an independent and secondary holobasidium origin in Basidiomycota.
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The problem of the origin and phylogeny of Agaricomycetes remains
controversial. However, various data accumulated in recent decades provide an
opportunity to reach some defi nite conclusions. Th e conclusions are: 1) Final
establishment of the circumscription of the class Agaricomycetes (Basidiomycetes
with dolipore septa without nanopores, with p...
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Citations
... • The emergence of mushrooms in the Agaricomycotina, which led to higher reproductive and dispersal fitness(Varga et al., 2019). This interpretation may well be too simplistic because this radiation involved a variety of morphological traits and combinations(Zmitrovich and Wasser, 2011). • (Partial) extinctions like those documented towards the end of the Cretaceous, during which two-thirds of all life perished. ...
The Devonian enigma: Prototaxites. Already during the 19th century, fossils several meters high were detected. Initially, they were interpreted as archaic plants, then as algae, rolled liverworts, or giant lichens (Moore et al., 2011). Recently, evidence has been mounting that they may have been ascomycetes, possibly lichenized (Retallack and Landing, 2014; Honegger et al., 2017). More information on Prototaxites (and much more) can be found in www.davidmoore.org.uk. Painting image courtesy Geoffrey Kibby (British Mycological Society). ABSTRACT Fungal evolution goes back for at least two billion years. From flagellate marine Chytridiomycota to terrestrial Asco-and Basidiomycota, fungal speciation-and the radiation of those species-occurred through multiple steps that were mainly triggered by key morphological (often symbiotic) innovations. The fossil record does document such evolutionary steps, albeit incompletely due to the scarcity of fossils; what evidence we have is preserved geological strata or amber. Through molecular analysis methods (examining the "molecular clock"), the fungal pathway through Earth's history can be amended and ancestral relationships elucidated. In the following historical review, important, history-illuminating fossils are depicted and put into evolutionary context. It also describes the delicate dependencies of fungal evolution on biotic and abiotic environmental circumstances, which sheds some light on the consequences of the present degradation of nature.
... • Entwicklung der Hutpilze bei den Agaricomycotina, was zu höherer Ausbreitungs-und reproduktiver Fitness führte ( Varga et al. 2019). Diese Auslegung mag zu simplistisch sein, weil diese Radiation eine Vielfalt morphologischer Merkmale und Kombinationen mit sich brachte (Zmitrovich & Wasser 2011). ...
Fungal evolutionary history goes back for at least two billion years. From flagel-
late marine Chytridiomycota to terrestrial Asco- and Basidiomycota it took multiple speciation and radiation steps. These steps were mainly triggered by key innovations of morphological and symbiotic nature. The fossil record documents such evolutionary steps, albeit incompletely due to the scarcity of fossils, be they from geological strata or amber. By molecular methods (“molecular clock”) the fungal pathway through earth’s history can be amended, and ancestral relationships elucidated. Important fossils are depicted and put into the evolutionary context in this review. It also describes the delicate dependencies on biotic and abiotic environmental circumstances, which sheds some light on the consequences of the present degradation of nature.
... Actually, phragmobasidia are observed also in basic lines of Agaricomycotina, including certain in the Agaricomycetes (Fig. 2IeK;Hibbett, 2006;Oberwinkler, 2012). Holobasidia in contrast occur also in nature in lines of the Ustilagomycotina and in taxa of the Pucciniomycotina Begerow et al., 2006;Oberwinkler, 2012) and appear to be of polyphyletic secondary origins (Zmitrovich and Wasser, 2012). Furthermore, simple stipitate-capitate and resupinate basidiocarps of minute size have also been described in distinct families of the Pucciniomycotina (Oberwinkler and Bandoni, 1982;Aime et al., 2006;Oberwinkler, 2012). ...
Fruiting body formation in Agaricomycetes (Agaricomycotina) represents the most complex developmental processes known in the fungal kingdom. Shapes range from simple resupinate forms with open hymenia through to closed puff-balls and false truffles with internally hidden hymenia and include brackets and stiped mushrooms, which may have open caps throughout or which open during development, where the hymenia cover the surfaces of gills or pores. Mushroom shapes and features do not necessarily reflect close or distant phylogenetic relationships. Thus, morphological characteristics have lost some of their former significance in taxonomy. The onset and progress of courses of processes in mushroom formation are determined by the sum of various genetic, physiological and environmental factors. Shapes of mushrooms can be dramatically changed by mutations and by adverse environmental conditions. Events in normal fruiting body formation may run in parallel or behind each other in the form of ‘subroutines’ that have different degrees of independency to each other. Alterations in details or in places and orders of distinct subroutines and omissions can result in abnormal mushrooms. Developmental processes, time courses and tissue structures have been described in more details for a few model species (such as the hemiangiocarpous Coprinopsis cinerea and the gymnocarpous Schizophyllum commune) and some species of commercial interest (e.g. the gymnocarpous Auricularia auricula-judae and the hemiangiocarpous Agaricus bisporus). Morphological descriptions of fruiting body development in these four species are summarized here. Agaricomycetes have relatively large genomes with more than 10,000 different genes, many of which are expressed during the fruiting process in specific pseudoparenchymatous tissues (plectenchyma) or possibly only in individual cells within a tissue and at specific times. To understand the distinct functions of all these genes in space and time will require very fine dissection and analysis of distinct mushroom tissues and cells in future studies.
Highlights
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Morphological aspects of fruiting bodies and their development in Agaricomycetes and other Basidiomycetes are discussed.
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Taxonomic and evolutionary perspectives are presented.
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Genetic, physiological and environmental factors effecting morphological plasticity are addressed.
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Fruiting in Auricularia, Agaricus, Coprinopsis and Schizophyllum is described in detail.
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Estimates are provided for the numbers of different cell types involved with fruiting body development.
... It is, for instance, hazardous to infer the morphology of the ancestor of the whole clade. As in better known fungal groups such as the basidiome-forming Agaricomycotina, the combination of various traits, rather than single ones, is the only possibility to identify species morphologically (Zmitrovich & Wasser 2011). Some other traits that can possibly be discriminating for the different subgroups can be inferred by searching into the metabolism of these organisms and their enzymatic machinery. ...
The Saprolegnia-Achlya clade comprises species of major environmental and economic importance due
to their negative impact on aquaculture and aquatic ecosystems by threatening fishes, amphibians, and crustaceans.
However, their taxonomy and phylogenetic relationships remain unresolved and suffer from many inconsistencies,
which is a major obstacle to the widespread application of molecular barcoding to identify pathogenic strains with
quarantine implications. We assessed phylogenetic relationships of major genera using three commonly used
markers (ITS, SSU rRNA, and LSU rRNA). A consensus tree of the three genes provided support for nine clades
encompassing eleven documented genera and a new clade (SAP1) that has not been described morphologically.
In the course of this study, we isolated a new species, Newbya dichotoma sp. nov., which provided the only culture
available for this genus. In parallel, we attempted to summarize the evolution of traits in the different genera, but
their successive reversals rendered the inference of ancestral states impossible. This highlights even more the
importance of a bar-coding strategy for saprolegniacean parasite detection and monitoring.
A basidiomycete fungus from Vietnam, grown in a moist chamber on bark (as substrate) was identified as Hyphobasidiofera malaysiana. The isolation of this fungus into axenic culture allowed for investigations such as culture morphology, large and small subunit molecular phylogenies, life cycle karyology, and mating experiments. Comparative morphological data revealed that this species belongs to Rogersiomyces and the name Rogersiomyces malaysianus comb. nov. is proposed. Molecular studies revealed close relationships of Rogersiomyces, Sistotrema sensu lato, and Hydnum sensu stricto (Cantharellales, Agaricomycetes). The fungus produces binucleate basidiospores that germinate to form clamped and dikaryotic mycelium. The cultural characters and reproductive structures of this unusual sistotremoid fungus are described. It was concluded that the characteristic of dikaryotization into basidium, ephemeral basidiomata, and statismosporic basidia represent an adaptation of this fungus to irregular, but plentiful moistening during monsoon climate.
