Fungi

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Fungi
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Characteristics

• Multicellular (few exceptions like yeast)
• Eukaryotic
• Heterotrophic, break down food then absorb,
  saprotrophic
• Some are parasitic, cause disease
• Economically important, food, fermentation,
  medicines
• Mutualistic relationships

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Structure of Fungi

• Mycelium make up body of most fungi
• Hyphae network of fibers that make up mycelium,
  increase surface area for fungi
• Some have septa cross walls, have pores
• Non-septate fungi, multinucleated
• Cells contain chitin in cell wall, lack
  chloroplasts
• Non motile, not flagella, grow toward food source

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Reproduction

• Sexual
• haploid hyphae?dikarytoic?diploid zygote
• Hyphae from 2 different fungi meet and fuse
• Produce windblown spores to insure dispersal
• Spore reproductive cell that develops into a
  new organism without the need to fuse with
  another reproductive cell.

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Reproduction

• Asexual
• Production of spores by specialized part of
  single mycelium.
• Fragmentation and budding (yeast) can occur

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Fungi Evolution

• 570 mya
• Maybe evolved from red algae (both lack flagella)
• Thought to be part of Plantae and Protista
  kingdoms
• Fungal groups are classified according to
  differences in life cycle and type of structure
  that produces spores.

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Phyla Zygomycota

• Saprotrophic, in soil and food, some parasitic
• Black bread mold Rhizopus stolonifer
• Stolon are horizontal hyphae on surface of bread
• Rhizoids grow into bread, anchor the mycelium and
  carry out digestion.
• Sporangium produces spores called
  sporangiospores
• Zygospore seen in sexual repro.
• Forms prior to meiosis and production of spores
• 23.3 page 401

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Phylum Ascomycota

• Sac fungi
• Sexual ascomycetes (yeasts, red bread molds,
  mildews, morels, truffles, chestnut blight,
  ergot)
• Asexual ascomycetes, no sexual repro. observed,
  (Aspergillus, Candida and Penicillium molds)
• Penicillium has been renamed Talaromyces
• Essential to digesting not easily decomposed
  materials such as cellulose, jet fuel)

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Sac Fungi

• Symbiotic
• lichens (with algae),
• plant roots (mycorrhizae)
• Reproduction conidiospores (spores)
• Ascus fingerlike sac that develops during
  sexual reproduction
• Fruiting body reproductive structure where
  spores are produced and release.

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Economical benefits/ non-benefits

• Food beer, wine, cheese, coke
• Medical antibiotics, steroids, cyclosporin
• Disease ringworm, rose gardeners disease,
  Chicagos disease
• Yeasts Candida - infections
• Molds Aspergillus soy sauce, pathogenic to
  humans, carcinogen

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Basidiomycota

• Club fungi mushrooms, toadstools, puffballs
• Food, disease (smuts and rusts)
• Reproduction usually sexually
• Basidium club shaped structure in which spores
  develop

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Symbiotic relationships

• Lichens fungus and green algae or
  cyanobacteria.
• Thought of as mutualistic but may be parasitic,
  algae do not benefit
• 3 types, environmental indicators, live in
  extreme conditions
• Mycorrhizae soil fungi and roots of most plants
• Plants more successful in poor soils
• Helps plants acquire mineral nutrients