Asexual Reproduction of Ascomycota:
✔ What are Reproduction?
✔ Asexual Reproduction??
✔ Asexual Reproduction in Ascomycota?
✔ Types of Asexual Reproduction in Ascomycota??
✔ Asexual spores?
✔ Conidia formation??
✔ Conidiospores, mitospores??
• Biological proccess by which new individual organisms Offspring are
produced from their Parents
• Reproduction is a fundamental feature of life
• Each individual organism exists as the result of Reproduction.
Types of Reproduction:
• Asexual Reproduction
• Sexual Reproduction
4. Asexual spores:
Different types of asexual spores can be identified by colour, shape, and how they are
released as individual spores.
Types of Asexual spores:
⮚ The most frequent types are the single-celled spores, which are designated amerospores.
⮚ If the spore is divided into two by a cross-wall (septum), it is called a didymospore.
When there are two or more cross-walls, the classification depends on spore shape.
⮚ If the septae are transversal, like the rungs of a ladder, it is a phragmospore,
⮚ If they possess a net-like structure it is a dictyospore.
⮚ If ray-like arms radiate from a central body it is saturospores
⮚ If the entire spore is wound up in a spiral like a spring.it is helicospores
⮚ Very long worm like spores with a length to diameter ratio of more than 15:1are called
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.
Types of Asexual Reproduction in Ascomycota:
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…
▪ Conidia Formation
6. 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 conidiospores and mitospores.
The conidiospores commonly contain one nucleus and are products of mitotic cell divisions and thus are sometimes call
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.
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 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.
The diverse conidia and conidiophores sometimes develop in asexual sporocarps with different characteristics (e.g.
aecervulus, 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 sporodochium. This is a cushion of
conidiophores created from a pseudoparenchymatous stroma in plant tissue. The pycnidium is a globose to flask-shaped
parenchymatous structure, lined on its inner wall with conidiophores. The acervulus is a flat saucer shaped bed of
conidiophores produced under a plant cuticle, which eventually erupt through the cuticle for dispersal.
9. Budding :
⮚ Having and Developing bud
⮚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
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.