Basidiomycetes

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Basidiomycetes

• Characteristics
• Septate mycelium
• Basidia and basidiospores
• Clamp connections. Not all Basidiomycetes
  produce these, but when a fungus does it will
  always be a basidiomycete.

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Basidiomycetes

• Characteristics
• Two main groups, based on morphology of basidia.
• Basidia are septate and deeply lobed
• Order Uredinales the rusts
• Produce all five spore stages aeciospores,
  uredospores, teliospores, basidiospores and
  spermatia (aka pycniospores)
• Important genera Puccinia, Gymnosporangium
• Order Ustilaginales the smuts
• Produce only basidiospores and teliospores
• Important genera Ustilago, Tilletia

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Order Uredinales
Order Ustilaginales
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Basidiomycetes

• Characteristics
• Two main groups, based on morphology of basidia.
• Basidia are unicellular, non-septate wood decay
  fungi
• Order Aphyllophorales (aka Polyporales) the
  bracket fungi
• Hymenium lines small pores on underside of
  sporophore
• Important genera Polyporus, Fomes
• Order Agaricales the mushrooms
• Hymenium lines gills (lamellae)
• Important genera Armillaria, Agaricus

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Aphyllophorales
Agaricales
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Basidiomycetes

• 5. Three types of hyphae
• Primary hyphae develops from a germinating
  basidiospore. Nuclear status n
• Secondary hypha results from fusion of two
  primary hyphae. Yields a nn cell that continues
  to grow as a nn hyphae
• Tertiary hypha exactly the same as secondary
  hypha. nn However it has thick walls that enable
  production of fleshy and wood sporophores

Primary hyphae
Primary hyphae
Secondary hyphae
Tertiary hyphae
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The Rusts

• These are obligate parasites. Generally these
  require two host to complete their lifecycle.
• Primary hosts the host on which basidia and
  basidiospores are produced.
• Alternate host the other host in the life cycle
  on which spermagonia and aecia are produced
• Alternative host the host that a pathogen can
  infect in place of the primary or alternate
  hosts.
• Heteroecious organisms with a primary and
  alternate host.
• Autoecious organisms that have only a single
  (primary) host.
• Macrocyclic rust long cycle rust. Produce all
  5 spore types.
• Demicyclic rust medium cycle rust. Omits
  uredia.
• Microcyclic rust short cycle rusts. Produces
  basidiospores, teliospores and spermatia.

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Wheat stem rust, caused by Puccinia graminis
tritici
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Cedar apple rust, caused by Gymnosporangium
juniperi-virginianum lacks the uredia stage no
repeating stage
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The Smuts

• Unique characteristics of smuts (vs. rusts)
• They are not obligate parasites. We can grow
  them in culture.
• They show a very high degree of selectivity.
  They attack not only certain host but certain
  tissues of the host.
• Have only tow spore types basidiospores and
  teliospores.
• Example corn smut, caused by Ustilago maydis

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Review

• Wheat stem rust all spore types
• Cedar apple rust lacks ureida
• Coffee rust no aecial stage
• Smuts basidiospores teliospores only