Editing Ascomycota (section)

== Sexual reproduction in ascomycetes ==

Ascomycetes are 'spore shooters'. They are fungi which produce microscopic spores inside special, elongated cells or sacs, known as 'asci', which give the group its name.

Asexual reproduction is the dominant form of propagation in the Ascomycota, and is responsible for the rapid spread of these fungi into new areas. Asexual reproduction of ascomycetes is very diverse from both structural and functional points of view. The most important and general is production of conidia, but chlamydospores are also frequently produced. Furthermore, Ascomycota also reproduce asexually through budding.

=== Conidia formation ===
Asexual reproduction may occur through vegetative reproductive spores, the [[conidia]]. The asexual, non-motile haploid spores of a fungus, which are named after the Greek word for dust (conia), are hence also known as {{Em|conidiospores}}. The conidiospores commonly contain one nucleus and are products of mitotic cell divisions and thus are sometimes called {{Em|mitospores}}, which are genetically identical to the mycelium from which they originate. They are typically formed at the ends of specialized hyphae, the conidiophores. Depending on the species they may be dispersed by wind or water, or by animals. Conidiophores may simply branch off from the mycelia or they may be formed in fruiting bodies.
[[File:Conidia Formation Redraw.svg|thumb|424x424px]]
The hypha that creates the sporing (conidiating) tip can be very similar to the normal hyphal tip, or it can be differentiated. The most common differentiation is the formation of a bottle shaped cell called a {{Em|[[phialide]]}}, from which the spores are produced. Not all of these asexual structures are a single hypha. In some groups, the conidiophores (the structures that bear the conidia) are aggregated to form a thick structure.

E.g. In the order ''Moniliales,'' all of them are single hyphae with the exception of the aggregations, termed as coremia or synnema. These produce structures rather like corn-stokes, with many conidia being produced in a mass from the aggregated conidiophores.

The diverse conidia and conidiophores sometimes develop in asexual sporocarps with different characteristics (e.g. acervulus, pycnidium, sporodochium). Some species of ascomycetes form their structures within plant tissue, either as parasite or saprophytes. These fungi have evolved more complex asexual sporing structures, probably influenced by the cultural conditions of plant tissue as a substrate. These structures are called the {{Em|[[sporodochium]]}}. This is a cushion of conidiophores created from a pseudoparenchymatous [[stroma (mycology)|stroma]] in plant tissue. The {{Em|[[pycnidium]]}} is a globose to flask-shaped parenchymatous structure, lined on its inner wall with conidiophores. The {{Em|[[acervulus]]}} is a flat saucer shaped bed of conidiophores produced under a plant cuticle, which eventually erupt through the cuticle for dispersal.
[[File:Conidia Formation Image.png|thumb|333x333px]]

=== Budding ===
Asexual reproduction process in ascomycetes also involves the budding which we clearly observe in yeast. This is termed a "blastic process". It involves the blowing out or blebbing of the hyphal tip wall. The blastic process can involve all wall layers, or there can be a new cell wall synthesized which is extruded from within the old wall.
[[File:Budding.png|centre|thumb|337x337px]]
The initial events of budding can be seen as the development of a ring of chitin around the point where the bud is about to appear. This reinforces and stabilizes the cell wall. Enzymatic activity and turgor pressure act to weaken and extrude the cell wall. New cell wall material is incorporated during this phase. Cell contents are forced into the progeny cell, and as the final phase of mitosis ends a cell plate, the point at which a new cell wall will grow inwards from, forms.