Ascomycetes


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Related to Ascomycetes: Basidiomycetes

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 ?
Indoor Outdoor Minimally Mold taxa Flooded Nonflooded Flooded flooded Alternaria species X X Ascomycetes X X X X Aspergillus/Penicillium species X X X X Aureobasidium species X X X Basidiomycetes X X Chaetomium species X Cladosporium species X X X X Curvularia species X X Ganoderma species X Smuts X X X Stachybotrys species X Ustilago species X X Wallemia species X Yeast X Although the remaining 31 taxa each constituted < 1% of the total spore count at any individual site, the concentrations of many were substantial given the overall high levels of spores found.
Most previous work has centered on the Ascomycetes (Fink 1915; Fink and Richards 1915) with particular attention to two genera (Corrington 1921).
Informal conversations led to a cooperative research and development agreement (CRADA) to tap a virtual treasure of some 500 ascomycete species.
Cellulase-producing fungi are widespread among fungi and include species from the ascomycetes, basidiomycetes and also few anaerobic species [19].
Cordyceps militaris, like Cordyceps sinensis, belongs to Ascomycetes and they parasitize insects at the larval stage and gradually grow into fruiting body expanded outside the insect larvae or pupae (Buenz et al.
Fonsecaea contains anamorphic ascomycetes belonging to the family Herpotrichiellaceae (order Chaetothyriales), which includes black yeasts and relatives (10-12).
Among the 44 species of fungus we recorded, there were 43 basidiomycetes, 1 ascomycetes, and l slime mold.
Among the 85 investigated species (101 samples, 10 families), 19 were associated with arbuscular mycorrhizal fungi (AMF) and 36 were infected by dark septate endophytes (DSE), which are identified as ascomycetes and here considered as a kind of mycorrhiza similar to the ericoid type.
2002) tested 26 wood decay basidiomycetes and 20 wood inhabiting ascomycetes by ITS-RFLP using several different primer pairs including ITS4B.
Since then, a total of 444 species have been described worldwide, distributed mostly in the higher groups of ascomycetes and basidiomycetes.
They focus on best practices and applications as they describe concepts and installations, including the Global Biodiversity Information Facility, the European Network for Biodiversity Information, networking taxonomic concepts flexibly, networking European biological collections databases, automated extraction of biodiversity information from taxonomic descriptions, using the grid in biodiversity informatics, an interactive database system for structured descriptive data of ascomycetes, linking and merging databases, and applications to such practical projects as rattan conservation in Borneo.