Division Ascomycota

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Division Ascomycota
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Main characteristics
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Sexual reproduction Life cycle and ascospore
formation
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Sexual reproduction Ascospore formation
A ascogonium antheridium B plasmogamy
C dikaryotic mycelium D crozier hook E-F
nuclear division G karyogamy H meiosis I
mitosis J ascus with ascospores
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Sexual reproduction Life cycle and ascomycetous
yeast
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Sexual reproduction Ascus
Usually elongated cylindrical, but can be globous
or spherical form Presence or absence Presence
or absence 1. Protunicate 2. Unitunicate 3.
Bitunicate
Shape Stalk Operculum Asci structure
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Sexual reproduction Ascus structure
Protunicate asci are usually more or less
spherical and are found in cleistothecia. They
have a thin, delicate wall and release spore
by deliquescing due to they have no
spore-shooting mechanism.
Unitunicate asci have a single wall (endotunica
and exotunica are fused)
thoughout the existence of the ascus. The
spores are released
through a terminal pore, slit or operculum.
Bitunicate asci have double wall,
i.e. endotu- nica and
exotunica. The outer wall is thin and
inextensible, while the inner wall is thick and
elastic. Prior to spore release, the
endotunicata usually expands and protrudes
from the ruptured exotunica and spores
are release through a pore of endotunica.
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Sexual reproduction Ascocarp
Ascocarp is a fruiting body bearing asci.
According to ascocarp structure, there are 5
types can be distinguished. 1. Naked asci (no
ascocarp) 2. Cleistothecium 3. Perithecium 4.
Apothecium 5. Pseudothecium or ascostroma
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Sexual reproduction Naked asci
The fungi form asci directly from zygotes or
single cells, without ascogenous hyphae or
ascocarp.
Saccharomyces cerevisiae
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Sexual reproduction Cleistothecium
Cleistothecium is a completely closed
ascocarp and have asci that are scattered
throughout the interior that is to call without
hymenium. Break- down of the cleistothecium
might be only one way to release the ascospore
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Sexual reproduction Perithecium
Perithecium is various shaped, but typically
flask-shaped or globous with a small ostriole.
Asci are arranged in a single fertile layer
throughout the base of perithecium and this
fertile layer is called hymenium. Paraphyses,
sterile cells, may be present among the asci.
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Sexual reproduction Apothecium
Aphthecium is usually cup-shaped or variable. The
asci form hymenium that entirely exposed.
Paraphyses are generally present in apothecia
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Sexual reproduction Apothecium
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Sexual reproduction Ascostroma (pseudothecium)
Ascostroma is a locule that forms in a stroma
where the asci are borne. This differs from a
perithecium that is formed within a stroma in
that a perithecial wall is formed by the
perithecium that delimits it from the stroma.
Elsinoe leaf spot
Elsinoe vacinii
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Classification The new classification
New classification of Ascomycota based on
molecular information (Sugiyama, 1993 Sukiyama
and Nishida, 1994)
Class Euascomycetes (Filamentous
ascomycetes) Class Protoascomycetes (Yeast and
Archiascomycetes) Class Laboulbeniomycetes
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Classification The classification in our class
A very old simply and classic classification
(modify from Alexopolos and Mims, 1979)
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Hemiascomycetes Order Protomycetales (yeast)
Species Saccharomyces cerevisiae Schizosaccharomyc
es pombe Candida utilis Candida
albicans Cryptococus neoformans Pneumocystis
carinii
Importance Fermentation, brewery, molecular
model Molecular model Food yeast Superficial and
systemic infection Pulmonary disease Effect to
central nervous system Pneumonia
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Hemiascomycetes infection by Candida albicans
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Hemiascomycetes Order Taphrinales
Order Taphrinales are all parasite on plant. A
well know species in this order is Taphrina
deformans, peach and almond leaf curl agent.
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Plectomycetes Chalkbrood due to Ascosphera apis
Top-left Infected larvae in their
cells Top-right Mummify larvae Bottom
Cleistothecia containing asci of
Ascosphera apis
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Plectomycetes Powdery mildew (??????)
Poedwey mildew is a plant disease caused by Order
Erysiphales. Some serious pathogens are
Uncinulla necator, Erysiphe graminis and
Sphaerotheca spp.
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Plectomycetes Powdery mildew (??????)
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Plectomycetes Dermatophytes (???????????????)
??????? (Tinea ???? Ringworm) ????????????????????
??????????? dermatophyte ???????????????????????
keratin ??? ???????????? ???????????? 3
???? ??? genus Epidermophyton, Microsporum
??? Trichophyton ??????????????? asexual spores
?????????????
Microsporum
Trichophyton
Epidermophyton
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Plectomycetes Dermatophytes (???????????????)
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Pyrenomycetes Flask fungi
Hypoxylon sp.
Xylaria sp.
Xylaria sp.
Xylaria sp.
Perithecium
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Pyrenomycetes Ergot of rye
The sclerotia of Claviceps
purpurea, the cause of ergot
of rye, produce a number of powerful
alkoloid, for example ergotamin,
ergometrin and ergonovin, which are used as
medicine to induce labor and prevent post partum
hemorrhage during childbirth.
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Pyrenomycetes Cordyceps
Cordyceps spp., the member of F.
Clavicipi- taceae are parasitic on either insect
or hypo- genous ascocarp. Cordyceps are also
used as traditional chainess medicine.
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Discomycetes Cup fungi
Vibrissea sp.
Piziza sp.
Cookeina sp.
Scutellinia sp.
Microstroma sp.
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Discomycetes Morel
Verpa sp.
Morchella esculenta
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Loculoascomycetes
Loculoascomycetes are generally characterized by
the production of bitunicate asci within
stromatic locules.
Apple scab
Ascocarp of Venturia inaequalis