Ascomycetes

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Related to ascomycete: deuteromycete, basidiomycete

Ascomycetes

[‚as·kō‚mī′sēd·ēz]
(mycology)
A class of fungi in the subdivision Eumycetes, distinguished by the ascus.

Ascomycetes

 

a class of higher fungi with about 2,000 genera, embracing 15,000 species. Ascomycetes are characterized by a multicellular mycelium and special spore-bearing organs, or asci, in which ascospores develop. Usually eight spores develop in each ascus. The asci appear as a result of the sexual process, which varies in different ascomycetes. In most species the asci develop internally or on the surface of the fruiting bodies; in Endo-mycetales they develop directly on the mycelium or on the budding cells, without formation of a fruiting body. The classification of ascomycetes is based on the structure of the fruiting bodies and the asci.

Many ascomycetes, including Plectascales, Perisporiales, and Pyrenomycetes, also reproduce asexually by means of conidia; this form of reproduction precedes the formation of asci at the end of the developmental cycle. In many fungi asci seldom develop; these fungi reproduce almost exclusively by means of conidia. A fungus of which only the conidial stage is known is often described as an independent, or imperfect, fungus. An ascomycete that produces conidia under one set of conditions often may not produce them under another.

Most ascomycetes live as saprophytes in soil, on dead plant tissues, on substrates of organic origin (manure, skin, hair), in food products, and in fermenting liquids. Ascomycetes include parasites of higher plants and the causative agents of mycoses in animals and humans. The vegetative period of some species is spent in the conidial stage as parasites on living plants; after the death of the plants the fungi transfer to saprophytic nutrition, forming spore-bearing asci by spring. Almost all fungi that participate in the formation of lichens are ascomycetes.

Many ascomycetes are the causative agents of diseases of cultivated and beneficial wild plants. They cause powdery mildew, canker, spot, scab, snow mold, and root rot. The conidial stages of many species cause spoilage of food products and feeds. Certain types of mold fungi (the genus Penicillium) are used in the production of cheese, bread, and antibiotics. Some ascomycetes are edible, for example, morels and truffles.

V. A. MEL’NIK

References in periodicals archive ?
The relative number of MCGs in the populations of ascomycetes has previously been used to indicate whether a pathogen has recently been introduced into an area or has been present for a longer time (ADAMS et al.
Samples of the Brettanomyces and all other known ascomycete yeast species are kept in the ARS Culture Collection's frozen storage vaults housed at the National Center for Agricultural Utilization Research (NCAUR) in Peoria, Illinois.
Faccal pellets of lichcnivorous mites contain viable cells of the lichen-forming ascomycete Xanthoria parietina and its green algal photobiont, Trebouxia arboricola.
It possesses the conserved anti-HIV (human immunodeficiency virus) CV-N domain, which is the same as the cyanovirin-N homology (CVNH) members that were isolated from filamentous ascomycetes and C.
Fabaceae); ns the Baltic Ascomycete Sea, endophytic Ahrenshoop, fungus strain 6650 Germany Chlohdium sp.
We report the first case of infection by Neosartorya hiratsukae, an ascomycete in which the conidial state resembles Aspergillus fumigatus.
A mushroom lectin from ascomycete Cordyceps militaris.
First report of a xylose-specific lectin with potent hemagglutinating, antiproliferative and anti-mitogenic activities from a wild ascomycete mushroom.
First report of a xylose-specific lectin with potent hemagglutinating, antiproliferative, and anti-mitogenic activities from a wild ascomycete mushroom.
These fungi represent different growth forms (yeast-like and filamentous) and diverse taxonomic groups, including Ascomycete, Basidiomycete and Zygomycete species.
Oxford and IBH, New Delhi Stadler M, Anke H, Arendholz WR, Hansske F, Anders U, Sterner O, Bergquist KE (1993) Lachnumon and Lachnumol A, New Metabolities with Nematicidal and Antimicrobial Activities from the Ascomycete Lachnum papyraceum (KARST).
Propineb (polymeric-Zinc propylen-bisdithiocarbamate) is one of the broad spectrum fungicide currently widely used as a protective treatment for several crops to control various fungi, especially Oomycetes, Ascomycetes and fungi imperfecti [1].