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Fungi
• DOMAIN Eukarya
• KINGDOM Fungi
• General Characteristics:
– Eukaryotic
– Non-motile
– Multicellular
– Heterotrophic via absorption (extracellular
digestion)
– Asexual and Sexual reproductive life cycles;
• Both results in spore formation
• Mitosis – nucleus does not break down or reform
• Most are free-living saprotrophic decomposer and feed on
dead organic material.
consumers
• Ecological importance:
– Recycling of nutrients within the ecosystem
producers
decomposers
nutrients
ENTER FOOD CHAIN
= made available
to producers
Decomposition
connects all
trophic levels
abiotic
reservoir
geologic
processes
return to
abiotic
reservoir
Some form symbiotic relationships:
• Parasitism
– Plants:
• rusts and smuts affect grains
• Cause of tree disease – Dutch Elm
– Man: causes mycoses (medically important )
• e.g. Thrush, yeast infections, ringworm, athlete's foot
• Mutualism
– Lichens - Fungi & cyanobacteria (or green algae)
• Grows on rock; Soil formers
• e.g. Crustose (crusty); Fruticose (shrubby); Foliose
(leafy)
– Mycorrhizae - “Fungus-root” in plants
• Increases surface area in plant roots – increases
absorption
• 2 Types:
– Arbuscular (penetrate roots)
– Ectomycorrhizae (surround roots)
• General economic importance: (pg. 374)
– Produce medicines: e.g. antibiotics (Penicellium
and cyclosporins)
– Produce foods: e.g. Cheese – roqueforts and brie
– Used in making of – breads, beers, and wines
– Consumed as delicacies: e.g. Truffles, morels, and
portabella
• (NOTE: Some deadly poisonous & some produce
hallucinogens like LSD)
• QUESTION: What economic impact does
“black” mold have? Rusts & smuts?
Structures:
• Hyphae - filaments which make-up the mycelium
(body)
• Mycellium - mass of hyphae; body of fungus
• Septa - divides hyphae into sections via crosswalls
• Cell Wall - composed of chitin
• Yeast - unicellular, round and not associated with
hyphae; reproduce by asexual budding
• Spore - reproductive cell that grows a new
organism; dispersal via wind; produced as a result
of asexual or sexual life cycle
• QUESTION: If a single fungus can produce billions
of spores, why aren’t there fungi everywhere?
Five basic groups
•
•
•
•
•
Chytridiomycota
Zygomycota*
Glomeromycota
Ascomycota*
Basidiomycota*
• Grouped by:
– Differences in life cycles
– Structures that produce spores (particularly in sexual part
of the life cycle
– Comparative molecular data
Phylum
Sexual
Reproductive
Structure
Zygomycota
Ascomycota
Zygospore
Asci
Lack asci
Basidiomycota Basidia
Structures that produce
spores – spores are
windblown
Septa
Example
absent
present
present
black bread molds
sac fungi
present
club fungi
imperfect fungi
• Phylum Chytridiomycota – chytridiomycetes or
chytrids
– Most closely related to ancestral fungi
– Aquatic, flagellated fungi
– Life cycle: both haploid and diploid multicellular
stages
– Motile zoospores
– Found in soil, fresh water and saline estuaries
• Phylum Zygomycota - black bread molds (e.g.
Rhizopus)
– Aseptate hyphae
– Sexual reproduction produces zygospores
– Most saprotrophs (living off dead organic materials;
recyclers)
– Some parasitic
• zygomycosis – infection by zygomycetes – often fatal –
requires extensive surgery and antifungal treatment.
• Phylum Glomeromycota – glomeromycetes
– Small group of fungi
– Tips of hyphae grow into plant roots
• Arbuscular mycorrhizae
– Asexual reproduction
• Phylum Ascomycota - sac fungi (e.g. cup fungi
& yeast)
– Account for 75% of all fungi
– Two main groups:
• Sexual Ascomycota
– Examples: baking & brewing yeast, morels & truffles, parasitic
to plants
– Plant diseases: Leaf curl fungi & mildews, Dutch elm disease,
Ergot (infects grain)
Asexual Ascomycota - sexual life cycle has not been
demonstrated (Deuteromycetes – imperfect fungi)
– Fungi Imperfecti - Contains the medically important fungi
– Examples of Mycoses: Range from skin , deeper tissue, systemic
infections
– Tineas (cutaneous dermatophytes) – e.g. ringworm, athlete’s
foot, & jock itch
– Aspergillosis – e.g. swimmer’s ears & lung infection
– Candidiasis – e.g. thrush & vaginitis; Causative agent Candida
albicans
• Phylum Basidiomycota - club fungi (e.g.
mushrooms, toadstools, puffballs, shelf fungi)
– Basidiocarps AKA fruiting bodies (cap)
– Some are:
• Responsible for rusts and smuts (parasitize cereal
crops)
• Delicacies (e.g. portabella and shiitake)
• Poisonous