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 ?
Circular Phylogram was constructed by adopting the distance tree of BLAST pairwise alignments comparison to find out the relationship of the species under study with other members of the ascomycetes.
[37] have reported high levels of polymorphism in ascomycete's soil fungus Emericella nidulans from stressful and arid environment with the help of SSR markers.
Six immunosuppressive from Ascomycete, Zopfiella longicaudata, found in a screening study monitored by immunodulatory activity.
Riqueza, porcentaje de ocurrencia y frecuencia de hongos detectados en cinco cultivares de mango (Mangifera indica L.) del banco de germoplasma del INIA-CENIAP Maracay Cultivares Hongos Criollo Hadden % IF % IF Ascomycetes Aithaloderma sp.
Molecular genetics of heterokaryon incompatibility in filamentous ascomycetes. Microbiology and Molecular Biology Reviews, v.64, n.3, p.489-502, 2000.
The Aspergillus oryzae belongs to a completely separate group of mushrooms, ascomycetes. Using a reconstructed gene structure the more robust specimen has been genetically modified in order to enable it to produce pleuromutilin at a vastly improved rate--more than 200 times faster (2106%) than the basidomycete.
Lichens are in fact an ecosystem comprising of a photobiont that can either be a green alga (Chlorophyta) or a cyanobacterium and a mycobiont that in most cases belongs to the Ascomycetes. The nomenclature of a certain lichen taxon stems from its mycobiont partner and they are taxonomically classified within the fungi where majority of lichen-forming fungi belong to Lecanoromycetes (Tehler and Wedin 2008).
This vine has all the symptoms of classical Esca disease where there is black goo staining in young xylem tissue, brown wood in older wood, and the classic white rot caused when basidiomycetes finish off what ascomycetes starts.
Microsporum, Trichophyton and Epidermophyton and where the perfect state of the species has been identified to the genus Arthroderma in the class Ascomycetes. (1)