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Ascomycetes - Phylum: Ascomycota
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The Ascomycota are the largest of the nine phylla that make up the Kingdom of the Fungi with nearly 65,000 species and counting. Whereas most of the Ascomycota produce 'fruiting bodies' they do not look like the typical mushroom most people are familiar with as they come in a staggering variety of shapes and colours. Many are saprophytes ie. they live on dead or decaying matter which they digest externally yet, many others are symbionts which means they have a mutual reliance with, and upon other organisms. Nearly all Lichens for instance, contain an ascomycete fungus as one of the partner organisms. Even though many of the Ascomycota are pathogens, they are also extremely useful in the production of medicines such as anti-biotics ie. Penicillium spp.
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The name, Ascomycota literally means 'sac fungi'. The Greek word 'askos' translates into 'sac' or' wineskin'. The sac, or ascus, to use its' proper name, is a tiny part of the fungus in which the spores are formed. Nearly all Ascomycita have many of these structures and the function they fill results in asexual reproduction.
The largest group within Ascomycota is the subphylum: Pezizomycotina. In simple terms, this group includes practically all of the sac fungi that have fruiting bodies one can actually see. Most of the Fungi partners of Lichens are included in this group. The subphylum: Taphrinomycotina is a much smaller group (likely less than 1,000 species) of mostly plant parasitic fungi. The damage some of them do to leaves is similar to insect galls. |
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Lastly, a third subphylum is recognised; the 'True Yeasts' also known as the 'Budding Yeasts' or the Saccharomycotina. This subphylum is currently divided into fifteen (*) families and a few genera of uncertain classification. Reproduction of these mostly microscopic organisms occurs by 'budding' rather than by some form of division of the cell. To simplify this: the cell grows a lump which, at maturity, separates from the 'parent cell' and starts life as a new individual.
(*) 13 to 15 depending on the source. |
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The organisms can be grown in petri dishes and they can be found on dead organic matter where they play an important role in the 'rotting process'. The best known example of a Saccharomycete Fungus is 'Baker's Yeast' or Saccharomyces cerevisiae. Many members of this subphylum are known to cause disease in plants, animals as well as humans, yet others are used in food production, eg. bread, obviously, and certain cheeses and other dairy products.
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The subphylum Saccharomycotina are not further elaborated upon on this web-site.
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References and links:
Text:
E.Beringen
E.Beringen