Fungi are eukaryotic organisms that are mostly multicellular and heterotrophic. They range from unicellular yeasts to complex multicellular mushrooms. Fungi have hyphae that can aggregate into structures like mycelium, sclerotia, and fruiting bodies. They reproduce both sexually through spores formed by meiosis and asexually through spores formed by mitosis. The five major phyla of fungi are Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota, and Deuteromycota. Fungi play important ecological roles as decomposers and through symbiotic relationships like mycorrhiz

1. Fungi
Fungi are eukaryotes
Nearly all multicellular
(yeasts are unicellular)
Heterotrophs
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2. Mushrooms – “Club Like” Fungi or Basidiomycete Fungi

3. mycelium
fruiting bodies
both are
composed
of hyphae

4. Bioluminescence in Mycena

5. The Characteristics of Fungi
Body form
Unicellular/multicellular
filamentous (tube-like
strands called hypha
(singular) or hyphae
(plural)
mycelium = aggregate
of hyphae
sclerotium = hardened
mass of mycelium that
generally serves as an
overwintering stage.
multicellular, such as
mycelial cords,
rhizomorphs, and fruit
bodies (mushrooms)
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6. The Characteristics of Fungi
Cell wall present, composed of cellulose and/or chitin.
Food storage - generally in the form of lipids and
glycogen.
Eukaryotes - true nucleus and other organelles present.
All fungi require water and oxygen (no obligate
anaerobes).
Fungi grow in almost every habitat imaginable, as long as
there is some type of organic matter present and the
environment is not too extreme.
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7. Fungi are Spore-ific!!!
Spores - asexual (product of
mitosis) or sexual (product of
meiosis) in origin.
Purpose of Spores
Dispersion
Resistant
Introducing new genetic
combinations into a
population
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8. Reproduce by spores
Spores are reproductive cells
Sexual (meiotic in origin)
Asexual (mitotic in origin)
Formed:
Directly on hyphae
Inside sporangia
Fruiting bodies
Amanita fruiting body
Pilobolus sporangia
Penicillium hyphae
with conidia
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9. Mushrooms – “Club Like” Fungi or Basidiomycete Fungi

10. Hyphal growth from spore
mycelium
germinating
spore
Mycelia have a huge surface area
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Armillaria ostoyae Oregon

11. Armillaria ostoyae (The honey mushroom)

12. Absorptive nutrition enables fungi to
live as decomposers and symbionts
Fungi are heterotrophs that acquire nutrients by
absorption
Secrete hydrolytic enzymes and acids to decompose
complex molecules into simpler ones that can be
absorbed
Specialised into three main types:
Saprobes
Parasitic fungi
Mutualistic fungi
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13. Heterotrophic by Absorption
Fungi get carbon from organic sources
Hyphal tips release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Product diffuses back
into hypha and is used
Nucleus hangs back
and “directs”
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14. Extensive surface area and rapid growth
adapt fungi for absorptive nutrition
Basic structural unit of
fungal vegetative body
(mycelium) is the hypha
Except for yeast, hyphae
are organised around
and within food source:
Composed of tubular walls
containing chitin
Provide enormous surface
area: 10cm2 of soil may
contain 1km of hyphae
with 314cm2 surface area
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15. Fungal hyphae may be septate or
aseptate
Hyphae of septate fungi
are divided into cells by
crosswalls called septa.
Hyphae of aseptate fungi
lack cross walls
(coenocytic).
Parasitic fungi have
modified hyphae called
haustoria, which
penetrates the host tissue
but remain outside cell
membrane.
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16. Er. Rinaldo John

17. Fungi reproduce by releasing spores that
are produced either sexually or asexually
In favourable conditions, fungi generally clone
themselves by producing enormous numbers of spores
asexually
For many fungi, sexual reproduction only occurs as
a contingency - results in greater genetic diversity
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18. Generalized Life Cycle of a Fungus
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19. Classification
& Phylogeny
motile spores
zygosporangia
asci
basidia
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20. Kingdom Fungi – you must know 5 Major Phyla
1. Chytridiomycota = Earliest fungi
2. Zygomycota = the Bread Molds
Rhizopus – black bread mold
3. Ascomycota = the Sac Fungi
Yeast, morels, truffles
4. Basidiomycota = the Club Fungi
Mushrooms, puffballs, bracket fungi, rusts, smuts,
toadstools
5. Deuteromycota = the Fungi Imperfecti

21. Mushrooms – “Club Like” Fungi or Basidiomycete Fungi
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22. Bracket Fungi – Basidiomycete Fungi
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23. Cup Fungi – Ascomycete Fungi

24. Chytridiomycota – “chytrids”
Chytridium growing on spores
Chytriomyces growing on pine pollen

25. Division Chytridiomycota: chytrids may
provide clues about fungal origins
Originally placed in
Kingdom Protista
Share many characteristics
with fungi:
Absorptive nutrition
Chitin cell walls
Hyphae
Enzymes / metabolism
Earliest fungi: evolved from
protists and retained
flagella
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26. Zygomycota – “zygote fungi”
Sexual Reproduction -
zygosporangia
Asexual reprod. – common
(sporangia – bags of asexual
spores)
Hyphae have no cross walls
Grow rapidly
Decomposers, pathogens,
and some form mycorrhizal
associations with plants
Rhizopus on strawberries
Rhinocerebral zygomycosis

27. Division Zygomycota: dikaryote structures
formed during sexual reproduction
Characterised by
dikaryotic zygosporangia
Mostly terrestrial - live in
soil or decaying material
Hyphae are coenocytic -
septa only found in
reproductive cells
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28. Ascomycota – “sac fungi”
Sexual Reproduction –
asci (sing. = ascus)
Asex. Reprod. – conidia
Cup fungi, morels,
truffles
Important plant parasites
& saprobes
Yeast - Saccharomyces
Decomposers,
pathogens, and found in
most lichens
A cluster of asci with spores inside
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29. Sac fungi diversity

30. Basidiomycota – “club fungi”
Sexual Reproduction –
basidia
Asexual reprod – not so
common
Long-lived dikaryotic
mycelia
Rusts & smuts –plant
parasites
Mushrooms, polypores,
puffballs, boletes, bird’s nest
fungi
Enzymes decompose wood,
leaves, and other organic
materials
Decomposers, pathogens,
and some form mycorrhizal
associations with plants
SEM of basidia and spores

31. Division Basidiomycota: club fungi
Characterised by dikaryotic
mycelium that reproduces
sexually via basidiocarps
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32. Deuteromycota – Form Phylum
“Imperfect Fungi”
Fungi that seldom or never reproduce sexually.
Asexual reproduction by vegetative growth and
production of asexual spores common.
Members are not closely related and are not
necessarily similar in structure or appearance; do not
share a common ancestry, polyphyletic = coming
from many ancestors.
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33. Moulds
Rapidly growing fungus
with no sexual stages
May develop into a sexual
fungus, producing
zygosporangia, ascocarps
or basidiocarps
Moulds with no known
sexual stage are known as
Deuteromycota or
imperfect fungi:
Penicillium
– Flavour for blue cheeses

34. Molds
Rapidly growth
Asexual spores
Many human importance
Food spoilage
Food products
Antibiotics, etc.
Antibiotic activity
Noble Rot - Botrytis

35. Yeasts
Single celled fungi
Adapted to liquids
Plant saps
Water films
Moist animal tissues
Candida
Saccharomyces

36. Yeasts
Unicellular: reproduce
Asexually by budding
Sexually by producing asci or
basidia
Saccharomyces cerevisiae
is most important
domesticated fungus:
Baking and brewing
Model organism
Can cause problems:
Rhodotorula: shower curtains
Candida: “thrush”

37. Lichens
“Mutualism” between
Fungus – structure
Alga or cyanobacterium
– provides food
Three main types of
lichens:
Crustose lichens form flat
crusty plates.
Foliose lichens
Fruticose lichens
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38. Crustose
Foliose
Fruticose

39. Lichens
Symbiosis of algae with
fungal hyphae
The alga:
Provides fungus with food
May fix nitrogen
Fungus provides good
environment for growth:
Hyphal mass absorbs
minerals and protects algae
Produces compounds that:
– shield algae from sunlight
– are toxic - prevents
predation
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40. Lichen reproduction
Occurs as a combined unit
or independent
Fungi reproduce sexually
(usually ascocarps)
Algae reproduce asexually
by cell division
Symbiotic units reproduce
asexually by:
Fragmentation of parent
Formation of soredia: small
clusters of hyphae with
embedded algae
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41. Mycorrhizae
Specific, mutualistic
association of plant roots
and fungi
Fungi increase absorptive
surface of roots and
exchange soil minerals
Found in 95% of vascular
plants
Necessary for optimal
plant growth
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42. Mycorrhizae
“Fungus roots”
Mutualism between:
Fungus (nutrient & water uptake for plant)
Plant (carbohydrate for fungus)
Several kinds
Zygomycota – hyphae invade root cells
Ascomycota & Basidiomycota – hyphae invade
root but don’t penetrate cells
Extremely important ecological role of fungi!
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43. Ecological impacts of fungi
Ecosystems depend on fungi as decomposers and
symbionts: decompose food, wood and even plastics!
Some fungi are pathogens e.g. athlete’s foot,
ringworm etc.:
Plants particularly susceptible (e.g. Dutch elm disease)
Ergot - affects cereal crops: causes gangrene, hallucinations
etc.
Many animals, including humans, eat fungi:
In US, mushroom consumption restricted to Agaricus
We eat a range of cultivated and wild mushrooms.
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44. HUMAN-FUNGUS INTERACTIONS
Beneficial Effects of Fungi
Decomposition - nutrient and carbon recycling.
Biosynthetic factories. Can be used to produce drugs,
antibiotics, alcohol, acids, food (e.g., fermented products,
mushrooms).
Model organisms for biochemical and genetic studies.
Harmful Effects of Fungi
Destruction of food, lumber, paper, and cloth.
Animal and human diseases, including allergies.
Toxins produced by poisonous mushrooms and within food
(e.g., grain, cheese, etc.).
Plant diseases.
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45. ANTIBIOTICS SOURCES USES
Penicillin Penicillium notatum Used against gram+ bacteria.
Clinically it against pneumonia,
rheumatic fever, tonsillites, tetanus,
diptheria & many other diseases.
Griseofulvin Penicillium griseofulvum Used against mycosis.
Cephalosporin Cephalosporium
acremonium ( a marine
fungus)
Used against Gram+ & Gram –
bacteria; typhoid
Jawaharene Aspergillus spp. Used against small pox, influenza,
leukoderma, etc.
Clavicin Aspergillus clavatus Used against fungal diseses.
Some of the antibiotics obtained from fungi, their
sources & applications are listed below- in table