The ascomycètes ( Ascomycota ) constitute vast a junction of Champignon S, characterized by Spore S formed inside asque S. Among the ascomycètes, one finds many species useful for the Man like the Levure S used in Boulangerie, Brasserie and Vinification, of the well-known species of the mycologists amateurs like the Morille S, the Pézize S, the truffle S. This group also comprises many Moisissure S and mushrooms Phytopathogène S of the crop plants.

Classification

The classification of the ascomycètes was, and is always, the object of many revisions. Certain classifications are based on the morphology of asque, others on that of the Ascocarpe (body on, or in, which are formed the asques ones).

The most recent classification defines three subphyla of ascomycètes:

• the Taphrinomycotina, probably polyphyletic group, it contains four classes: Schizosaccharomycetes, Pneumocystidomycetes, Neolectomycetes, and Taphrinomycetes.
• the Saccharomycotina, group containing the " Yeast of boulangerie" Saccharomyces cerevisiae .
• the Pezizomycotina, group containing the greatest number of species.

Reproduction

The reproduction of Ascomycètes utilizes very variable mechanisms according to the species. It can be sexuée or asexual. For much of species, the forms sexuées and asexual (imperfect forms) were described separately, which explains the double denomination of certain species as a Ascomycète S and as a imperfect mushrooms (fungi imperfecti).

Asexual multiplication

The multiplication asexual (or vegetative) is prevalent at Ascomycètes. It is responsible for the fast expansion of these mushrooms. It is carried out by conidiospores or Conidie S coming from the budding of specialized sporocysts called Phialide S. In order to facilitate the dispersion of the conidies, the phialides is generally grouped at the end of stalks or conidiophores. The conidiospores can be dispersed by the wind, the water or of the animals.

Sexuée reproduction

the sexuée reproduction of Ascomycète utilizes a characteristic structure, the asque S, which are specialized sporocysts. Inside these asques, the sexuées spores are produced following a Méïose. They are called the ascospores, to differentiate them from the asexual conidiospores.

Ecology

Ascomycètes are largely widespread in all the types of environment, the ground, the fresh water and navy, the organic matter in decomposition… In addition, the distribution of the species individual is very variable: certain species are present on all the continents, while others are present in isolated regions, like the Truffe Tuber magnatum recontrée in France and Italy.

Ascomycètes play a central role in many ecosystem S. Saprophyte S, they are important décomposeurs who degrade a large variety of Organic matter. They absorb especially remains of vegetable matters. By breaking up substances like the Cellulose or the Lignin, they take an important place in the Cycle of carbon and the Cycle of the nitrogen.

The bearing fruit bodies of Ascomycètes can be used as food for various animals like Insecte S, Limace S and Escargot S, and Mammifère S like the Rongeur S, the Cervidé S and the Sanglier S.

In addition, about half of the species of Ascomycètes join by Symbiose Algue S or Cyanobactérie S to form the Lichen.

Ascomycètes include/understand a great number of species Pathogène S for the Végétaux (Oïdium S,…).

Certain Ascomycètes, like the Truffles and the Morille S can form with the roots of certain plants of associations mutualists of the type Mycorhize S.

Ascomycètes sailors can live in partnership with Plants or Marine algas.

There exist also certain numbers of species of Ascomycètes which are pathogenic for the human ones like Candida albicans or of the Aspergillus .

Other species have an enormous importance into agroalimentary: the Penicillium take part in refining many Fromage, Saccharomyces cerevisiae take part in the manufacture of the Pain, the Bière and the Vin. Penicillium notatum manufactures the Pénicilline.

References

• Boiron Patrick, Organization and Biology of Mushrooms. Collection 128, Nathan Editions, 1996.
• Bouchet P., Unlucky J.L., Madulo-Leblond G., Regli P. General and Medical Mycologie. collection Shortened, Masson 1989.
• Tree off life * Eriksson O.E., (ED.) 2006. Outline off Ascomycota - 2006. - Myconet 12:1 - 82.

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