Fungi Chapter 31
Plantae Fungi Animalia • Protista Monera
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
Some fungi are pathogens • About 30% of the 100,000 known species of fungi are parasites, mostly on or in plants. • American elms: Dutch Elm Disease • American chestnut: • chestnut blight Was once one of America's most dominant trees
Some fungi are pathogens • Other fungi, such as rusts and ergots, infect grain crops, causing tremendous economic losses each year.
Some fungi are pathogens • Curse of the Mummy
Some fungi are persistant Athletes Foot
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
Human hair Fungal hypha
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
Hyphae 25 µm Chytrids (1,000 species) Fungus-like protist Fig. 31-11 Zygomycetes (1,000 species) Fungal hypha Glomeromycetes (160 species) Ascomycetes (65,000 species) Basidiomycetes (30,000 species) ? Deuteromycota
The five fungal phyla can be distinguished by their reproductive features.
Division Chytridiomycota • mainly aquatic. • Some are saprobes, while others parasitize protists, plants, and animals. • chitinous cell wall • flagellated zoospores • the most primitive fungi
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.
PHYLUMGLOMEROMYCOTA • Previously With Zygomycota • Small Monophyletic Clade • Endomycorrhizae – Arbuscular Mycorrhizae • Produce branching Arbuscules
Fig. 31-15 2.5 µm
Plant-Fungal Relationships Mycorrhizae (“fungus roots”) 90% of tree species have this association Very important to absorption of water and nutrients
Soil surface Plant roots Mycorrhizae Increases s.a. for absorption
Division Ascomycota “Sac fungi”(truffles, yeast) Beer > 6,000 years Wine > 8,000 years Lichens Decomposers, pathogens “yeast” describes a form of fungi (i.e., non-hyphal) 60,000 species
Division Ascomycota Scarlet cup Morchella truffles
Division Ascomycota Close up of cheese showing blue-green mycelium of Penicillium roqueforti. Roquefort cheese
LICHENS Crusrose Fruticose Foliose
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
The life cycle of a club fungus usually includes a long-lived dikaryotic mycelium.
PHYLUM DEUTEROMYCOTA No 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
Penicillin Woops… now Ascomycota
Candida albicans “yeast infection”