Conidiomata (singular: Conidioma) are blister-like fruiting structures produced by a specific type of fungus called a
coelomycete. They are formed as a means of dispersing asexual spores call
conidia
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to th ...
, which they accomplish by creating the blister-like formations which then rupture to release the contained spores.
Structure
Conidiomata mainly consist of a mass of densely packed hypha which develops below the surface of the host cuticle, and the fungus may or may not use some of the host’s own tissue to construct the structure. Development of these structures can either occur just below the cuticle or below the epidermal layer of the tissue. Formation on the differing levels is dependent upon the type of conidiomata being formed. Five types of conidioma have been found and are classified as
acervuli,
pycnidia
A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or in ...
,
sporodochia,
synnemata and corenima.
Types
Acervuli
Acervuli is one of the two major groups of conidiomata (the other being pycnidia). Conidiomata of this type form just below the cuticle of host tissue and produce massive blisters which protrude fairly far into the outside environment. Acervuli also have a large opening at the top from which the conidia are released. ''
Colletotrichum
''Colletotrichum'' (sexual stage: ''Glomerella'') is a genus of fungi that are symbionts to plants as endophytes (living within the plant) or phytopathogens. Many of the species in this genus are plant pathogens, but some species may have a mu ...
'' and ''
Pestaloptiopsis'' are examples of genera which produce these structures.
Pycnidia
Pycnidia, the other major group of conidiomata, forms beneath the epithelial layer of host tissue. The structure resembles that of
ascospores
An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or ...
, and a pear-shaped structure produced entirely below the surface. This formations leaves the cuticle with only a minor bulge on the outside surface rather that a massive blister which was seen with Acervuli. Genera which produce this type of structure include
Phomopsis
''Phomopsis'' is a genus of ascomycete fungi in the family Valsaceae.
Species
Species include:
* '' Phomopsis arnoldiae''
* '' Phomopsis asparagi''
* ''Phomopsis asparagicola''
* ''Phomopsis azadirachtae''
* '' Phomopsis cannabina''
* '' Phomop ...
, ''
Botryodiplodia'', and ''
Phoma
''Phoma'' is a genus of common coelomycetous soil fungi. It contains many plant pathogenic species.
Description
Spores are colorless and unicellular. The pycnidia are black and depressed in the tissues of the host. ''Phoma'' is arbitrarily lim ...
''
Sporodochia and synnemata
Sporodochia are small, compact, slightly raised circles which form on host. ''
Deuteromycota'' and ''
Hyphomycetes
Hyphomycetes are a form classification of fungi, part of what has often been referred to as fungi imperfecti, Deuteromycota, or anamorphic fungi. Hyphomycetes lack closed fruit bodies, and are often referred to as moulds (or molds). Most hyphom ...
'' produce these types of structures.
Synnemata are large, fused conidiophores which form a strand resembling a stalk of wheat, with spores lining the outside of the structure. Genera which produce synnemata include ''
Doratomyces''.
References
{{Reflist
Fungal morphology and anatomy