Kingdom Fungi About 100,000 species
Uses: • medicine• food
Ecological value:• major decomposers• symbiotic relationships (N2 fixers)
Problems:• some strains are deadly• athletes foot• destroy library books• destroy crops
• About 30% of the 100,000 known species of fungi are parasites, mostly on or in plants.– American elms:
Dutch Elm Disease
Some fungi are pathogens
Was once one of America's most dominant trees
–American chestnut:
chestnut blight
• Other fungi, such as rusts and ergots, infect grain crops, causing tremendous economic losses each year.
Some fungi are pathogens
Kingdom Fungi
Eukaryotic, absorptive
Mostly multicellular (except few, e.g. yeast)
Heterotrophic (decomposers & parasitic)
Mycelium (body of hyphae)
Kingdom Fungi
• Firm cell walls (generally of “chitin”)
• “Spores” as reproductive bodies
• Unique chromosomes and nuclei
• Includes molds, yeasts, rusts, and mushrooms
• hyphae - the vegetative bodies of most fungi, constructed of tiny filaments
• mycelium -an interwoven mat of hyphae
Septate hypha:• multicellular• walls divided by septa
Ceonocytic hypha:• continuous cytoplasm
mass• multinucleate• no septa
Haustoria:
• Modified hyphae found in parasitic fungi
• Function: absorb nutrients from host
• Some fungi even have hyphae adapted for preying on animals.
Kingdom Fungi
Division Chytridiomycota
Division Ascomycota
Division Glomeromycota
Division Basidiomycota
Division Zygomycota
Division Deuteromycota
Fig. 31-11
Chytrids (1,000 species)
Zygomycetes (1,000 species)
Hyphae 25 µm
Glomeromycetes (160 species)
Fungal hypha
Ascomycetes (65,000 species)
Basidiomycetes (30,000 species)
Fungus-like protist
Deuteromycota?
• mainly aquatic.
• Some are saprobes, while others parasitize protists, plants, and animals.
• chitinous cell wall
• flagellated zoospores
• the most primitive fungi
Division Chytridiomycota
Division Zygomycota
“Zygote fungi”(bread molds)
Zygote = “mated” hyphal strands
Live in soil, water
Some are parasites
600 species
• The zygosporangia are resistant to freezing and drying.
• When conditions improve, the zygosporangia release haploid spores that colonize new substrates.– Pilobolus aiming its spores.
PHYLUM GLOMEROMYCOTA
• Previously With Zygomycota
• Small Monophyletic Clade
• Endomycorrhizae – Arbuscular Mycorrhizae
• Produce branching Arbuscules
Plant-Fungal Relationships
Mycorrhizae (“fungus roots”)
90% of tree species have this association
Very important to absorption of water and nutrients
Division Ascomycota
“Sac fungi”(truffles, yeast)
Beer > 6,000 years
Wine > 8,000 years
Lichens
Decomposers, pathogens
60,000 species“yeast” describes a form of fungi (i.e., non-hyphal)
Roquefort cheeseClose up of cheese showing blue-green mycelium of Penicillium roqueforti.
Division Ascomycota
• Ascomycetes are characterized by an extensive heterokaryotic stage during the formation of ascocarps.
Division Basidiomycota
“Club fungi”(mushrooms)
Club-shaped reproductive structure
Food
Plant diseases
25,000 species
PHYLUM DEUTEROMYCOTANo Longer Exist!!
• 22,000 species.• No known sexual stage.• Saprophytic, parasitic and predatory.• Many produce conidia. • Most classified as Ascomycota.• Fusarium wilt of tomato, potato and
cotton.• Athletes foot, ring worm
Division Deuteromycota
“Imperfect fungi”(penicillin)
Unrelated group
Asexual
No info on sexual cycle
25,000 species