This document provides a taxonomy of fungi, describing their classification system. It discusses the five major divisions of fungi: Ascomycota, Zygomycota, Basidiomycota, Chytridiomycota, and Deuteromycota. Each division is characterized by its unique sexual and asexual reproduction structures and stages. The classification of fungi is primarily based on their method of sexual spore production. Several medically important fungal genera that can infect humans are also outlined.

1. Taxonomic Classification of
Fungi
HTC MULAGO LECTURE SERIES
BUGA RUDOLF
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2. Taxonomy
•Organizing, classifying and naming of
living things
•Formal system originated by Carl von
Linné (1701-1778)
• Involves identifying and classifying of
organisms according to specific criteria
•Each organism is placed into a
classification system
•To find similarities and similarities
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3. Principles of Classification and
Nomenclature
Mycological Taxonomy
CLASIFICATION ABREVIATION TERMINATION
• KINGDOM (K.) FUNGI
• DIVISION (D) MYCOTA
• Subdivision (s.D). MYCOTINA
• CLASS (Cl.) MYCETES
• Subclass (s.Cl.) MYCETIDEAE
• ORDER (O.) ALES
• Suborder (s.O) INEAE
• FAMILY (F)/ ( am.) ACEAE
• Sub. FAMILY (s.F). (s.Fam.) OIDEAE
• TRIBE (T.) EAE
• GENUS ( g. )
• SUBGENUS ( sg. )
• SPECIES ( spp.)
• SUBSPECIES ( ssp..)
• VARIETY (var)
• RACE (r)
• ECOTYP ( E ) eco.t
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4. Principles of Classification and Nomenclature…
Modern Taxonomy
• Domain - Eukarya
• Kingdom - Fungi
• Phylum/Division - mycota
• Class - mycetes
• Order - ales
• Family - aceae
• Genus ----------
• Species ----------
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5. Principles of classification and
Nomenclature
• Definition of “species” in
microbiology
oType strains:
“Known” and well-characterized
pure cultures; can be used as
references for the identification of
unknowns
oAmerican Type Culture Collection
(ATCC)
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6. Principles…
• Species” vs. “Strain”
oSpecies: A specific or defined type
of organism, defined by similarity
with known species.
oStrain: Genetic variation within a
species
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7. Principles…
• Nomenclature
o Scientific name (Systematic Name)
o Binomial System of Nomenclature
o Genus name + species name
o Italicized or underlined
o genus name is capitalized and may be
abbreviated
o species name is never abbreviated.
E.g. Aspergillus fumigatus
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8. Classification of fungi
•Separation of taxa is primarily based on
the method of spore production of the
perfect or sexual state (telemorph)
•Five major divisions/phyla of fungi
i. Ascomycota (ascomycetes)
ii. Zygomycota (zygomycetes)
iii. Basidiomycota (basidiomycetes)
iv. Chytridiomycota (Chytrids)
v. Deuteromycota (Fungi imperfectii)
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9. Classification of fungi…
•The first four phyla (true sexual groups)
o Produce sexual spores (ascospores,
zygospores , basidiospores and
oospores respectively)
o All groups of fungi fungi infect
humans except Chytridiomycota
•Deuteromycota (Fungi imperfecti) are
accommodate fungi without a perfect
state (telemorphs) but represent asexual
state (anamorphs)
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10. Classification of fungi…
o Genera in Fungi imperfecti are called ``form
genera`` since they are not identified by using sexual
characteristics (zygospores , basidiospores, oospores
and ascospores)
o Fungi imperfecti are not classified on
‘’evolutionary relationship’’ e.g. Aspergillus
fischerianus
o Members of this group are known or referred by
their anamorphic names
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11. Classification…
• Chytridiomycota (Chytridiomycetes / Chytrids) are important
carriers of diseases in agriculture and lower cold blooded
animals
• Some genera are classified as Dermateceous because of the
presence of melanin in the cell walls of conidia, hyphae or
both, resulting in dark coloured fungus
• Three genera are classified as dermatophytes because they
attack hair, nail and skin on living humans
• Examples ( Epidermophyton, Microsporum and
Trichophyton), and Dimorphism is coded at species levels
• Genera that contain dimorphic species are referred to as
moulds e.g. Coccidiodes
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12. Classification…
1. Phylum – Zygomycota (Bread or Fin Moulds)
• Class-Zygomycetes
• Order- Mucorales (mucors, black bread molds)
• Family- Mucoraceae (Absidia, Mucor, Rhizopus)
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13. Classification…
2. Phylum – Ascomycota (sac fungi/common
moulds).
a) Class- Hemiascomycetes or Saccharomycetes
• Order- Saccharomycetales
• Family- Saccharomycetaceae (Candida sp).
b) Class- Pneumocystiodiomycetes
• Order- Pneumocystidiales
• Family- Pneumocystidiaceae ( Pneumocystis jirovecii)
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14. Classification…
c) Class- Plectomycetes or Eurotiomycetes
•Order1- Eurotiales
•Family- Eurotiaceae ( Aspergillus,
Penicillium)
•Order2- Omygenales
•Family- Gymnoascaceae
−Azellomyces (Blastomyces dermatidis,
Histoplasm capsulatum)
−Arthroderma (Microsporum, Trichophyton,
Epidermophyton).
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15. Classification…
d) Class- Pyrenomycetes or Sordariomycetes.
•Order- Ophiostomatales
•Family- Ophiostomataceae (Sporothrix
schenckii)
3. Phylum – Basidiomycota (club
fungi/mushrooms, toad stools)
• Class- Ustilagrinomycetes
• Order- Mallasseziales (Mallassezia furfur)
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16. Classification…
4. Pylum- Deuteromycota or Fungi
Imperfecti
a) Class- Blastomycetes
•Order- Cryptococeales
•Family- Cryptococcaceae
•Genera ( Candida,
Cryptococcus,Malassezia,Pityrosporum,
Rhodotorula, Trichosporon)
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17. Classification…
b) Class- Hyptomycetes
•Order- Moniliales
•Family- Moniliaceae ( Aspergillus,
Blastomyces, Coccidiodes,
Epidermophyton, Geotricum,
Histoplasma, Paracoccidiodes,
Penicillium, Sporothrix, Trichophyton ,
etc.)
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18. Ascomycota
•Ascomycetes all have ascospores borne
in asci (sexual stage)
•Hyphae bear numerous septa
•Many are yeasts ascomycetes
•Asexual reproduction is by conidia that
always lack motility
•Sexual reproduction results into ascus
formation
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19. Ascomycota…
•Asci are packed together in a cup or flask-
shaped ‘ascocarp’
•Mostly terrestrial, some occur in fresh water
or marine habits
•Occur every where, year round and as minute
black dots on rotting wood or on lichen
•Associated with food spoilage and ergotism
•Some research tools in genetics and
biochemistry
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20. Zycomycota
•Produce zygospores, non motile
•Have coenocytic hyphae with many haploid nuclei
•Asexual reproduction is by sporangia or conidia
•Sexual reproduction produces tough, thick-walled
zygotes (zygospores)
•Members are usually terrestrial but rarely
encountered in water
•Grows on moist carbohydrate rich surfaces
(e.g.breads,fruits, vegetables, etc).
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21. Zycomycota…
•Special hyphae (rhizoids) penetrate
substrate to absorb nutrients
•Other hyphae (stolons) become erect,
arch back into the substratum to form
new rhizoids
•Other hyphae remain erect producing at
their tips asexual sporangia filled with
black spores giving the mold its
characteristics colour
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22. Zycomycota…
•Rhizopus reproduces asexually, unless
food becomes scarce then sexual
reproduction starts ( +ve and –ve strains)
•Mating hyphae produce progametangia
that matures into gametangia
•After fusion of the gametangia, the
nuclei of the 2 gametes fuse forming
zygote,
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23. Zygomycota…
•Zygote develops a thick, rough and
black wall and becomes a dormant
zygospore
•Meiosis occur during germination,
zygospore splits open and reproduces
hypha that bears an asexual sporangium
and the cycle continues
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24. Basidiomycota
•Large group of mushrooms and puffballs
•Characterized posses basidia that are
involved in sexual reproduction) and
produce basidiospores
•Basidia are held in fruiting bodies called
the basidiocarps
•Hyphae are septate
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25. Basidiomycota…
•Lack motile spores
•Many hyphae bear ‘’clamp connections’’
with specialized role in nuclei migration
•Asexual spores produced as conidia
•Members are mainly terrestrial.e.g.
Amaniota phalloides is toxic.
•Important Basidiomycete is Cr.
neoformans important human pathogens
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26. Chytridiomycota/Chytrids
•Simplest and true fungi
•Produce asexual and sexual spores in
sporangia
•Asexually produce motile zoospores that
bear posterior whiplash flagella
•Zoospores (swimming cells) escape to
the environment
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27. Chytridiomycota/Chytrids
•Zoospores are microscopic and may be
singlecelled or small multinucleate mass
of a true mycelium
•Rarely encountered as moulds
•Terrestrial and aquatic
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28. Deuteromycota/Fungi
Imperfecti
•Taxonomic classification is based on
sexual reproduction
•Fungus without sexual phase (perfect
stage) is placed within this phylum
•Molecular systematics places the
Deuteromycota among their closest
relatives in the Eumycota.
•Produce asexual conidia
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29. Deuteromycota/Fungi
Imperfecti…
•Alternation of reproductive phases:
Asexual (anamorph), Sexual
(teleomorph) and both (synanamorph)
•Most fungi imperfecti are terrestrial
•Several species are human pathogens,
causing athlete’s foot, ring worm and
histoplasmosis
•Some produce antibiotics e.g. Penicillin ,
Griseofulvin, etc.
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