Chytridiomycota: earliest fungi; evolved from protists and retained flagella
Originally placed in Kingdom Protista
Share many characteristics with fungi:
Absorptive nutrition
Chitin cell walls
Hyphae
Enzymes / metabolism
Zygomycota: decomposers, pathogens, and some form mycorrhizal associations with plants
Sexual Reproduction – zygosporangia: resistant to heat/cold and site of karyogamy
Asexual reproduction: haploid spores
Coenocytic
Grow rapidly
Zygosporangia, which are resistant to freezing and drying, can survive unfavorable conditions
Some zygomycetes, such as Pilobolus, can actually “aim” their sporangia toward conditions associated with good food sources
Ascomycota: important plant parasites & saprobes
Sexual Reproduction – asci (sing. = ascus)
Asex. Reprod: enormous numbers of asexual spores called conidia
Conidia are not formed inside sporangia; they are produced asexually at the tips of specialized hyphae called conidiophores
Cup fungi, morels, truffles
Yeast - Saccharomyces
Decomposers, pathogens, and found in most lichens
Basidiomycetes: important decomposers of wood / plant material
Named after transient diploid stage: basidium
Include:
Mycorrhiza-forming mutualists
Mushroom-forming fungi
Plant parasites e.g. rusts and smuts
Characterized by dikaryotic mycelium that reproduces sexually via basidiocarps
Haploid basidiospores grow into short-lived haploid mycelia: under certain conditions, plasmogamy occurs
Resulting dikaryotic mycelium grows forming mycorrhiza or mushrooms (basidiocarps)
Mushroom cap supports and protects gills: karyogamy in the terminal, dikaryotic cells lining the gills produces diploid basidia
Resulting basidium immediately undergoes meiosis producing 4 haploid basidiospores
Asexual reproduction less common than in ascomycetes
Rapidly growing fungus with no sexual stages
May develop into a sexual fungus, producing zygosporangia, ascocarps or basidiocarps
Molds with no known sexual stage are known as Deuteromycota or imperfect fungi:
Penicillium
Flavor for blue cheeses
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”
Rapid growth
Asexual spores
Human importance:
Food spoilage
Food products
Antibiotics, etc.