Notes: Fungi classifications

Fungi classifications

  1. are based on the plasmogamic structures, duration of dikaryon existence, and the location of karyogamy.

  2. are named after the types of bodies where karyogamy occurs.

Zygogomycota, or zygote fungi.

Facts:

  1. 600 discovered species.
  2. form mycorrhizae (mutualism in plant roots).
  3. have coenocytic hyphae with septa only at the spores
  4. name comes from the zygosporangium, a metabolically dormant, resistant dikaryon-diploid made in the sporangium.
  5. an example of a zygote fungi is Rhizopus:  its zygosporangia resist dessication and freezing.

Right:  Blue indicates a dikaryon after plasmogamy and a diploid after karyogamy.

 zygomycota, sexual reproduction diagram of

Ascomycota, or sac fungi.

Facts:

  1. 60,000 species discovered.
  2. include truffles, yeasts, and morels; as well as plant pathogens and other saprobes.
  3. the antheridium is "female"; the ascogonium "male".
  4. 50% are lichens; truffles and morels have mycorrhizae; others live in mesophyll cells and release toxins to keep pests out.
  5. karyogamy and meiosis in the asci create spores that are released when the asci break.
  6. many of these fruiting bodies are visible to the eye (unlike zygomycetes).
  7. asexual reproduction is the creation of conidia - spores produced at the tips of hyphae.

Right:  Blue indicates dikaryotic areas of the fungus.

 ascomycota, sexual reproduction diagram of

Basidiomycota, or club fungi.

Facts:

  1. 25,000 species discovered.
  2. basidium is a diploid cell in a basidiocarp where meiosis occurs.
  3. include parasites, saprobes and mycorrhizal symbionts.
  4. the saprobes are the best at decomposing lignin (a woody tree component).
  5. of all saprobic club fungi half form mycorrhizae; rarely is a club fungus solely parasitic.
  6. its dikaryotic mycelium lives a long time then produces basidiocarps.
  7. produce "fairy rings" in your backyard.  How?  the mycelium doesn't create spores - just keeps growing, fertilizing grass as it moves by releasing its enzymes (previously described); however, when the area of enzymatic activity passes some grass that grass dies because it became dependent on the extra nutrients supplied by the mycelium during growth.
 basidiomycota, sexual body diagram of
dikaryotic cap
a fairy ring

Next:  "Unique Fungi."