Healthy Plants

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Chytridiomycota chytrids

• Simple fungi
• Produce motile spores
• Mostly saprobes and parasites in aquatic habitats
• Could just as well be Protists

Fig 31.5 Chytridium growing on spores
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Part of a grass root with large sporangia (sp) of
Olpidium brassicae within the root cells. At
maturity the sporangia release zoospores through
exit tubes (et). Several zoospore cysts (cy) can
be seen on the root.
(a) Zoospore cysts have germinated to produce
short tubes that penetrated the root cell wall
then released the cyst content as a naked
protoplast into the host cell. Stellate resting
spores seen in early stages of development (b)
and in mature form (c).
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Zygomycota zygote fungi

• Sex - zygosporangia
• Asex - common
• Hyphae have no cross walls
• Grow rapidly
• Mycorrhizas

Fig 31.6 Rhizopus on strawberries
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• Rhizopus fruit rot

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Ascomycete Spores

• Asexual Spores

• Sexual Spores

• Conidia

• Ascospore

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• Ascocarp fruiting body containing ascospores in
  asci
• Ascospore sexual spore
• Ascus (asci) sack containing 8 ascospores

hyaline
colored
Ascus
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• No Ascocarp
• Cleistothecium
• Perithecium
• (pseudothecium or pseudoperithecium)
• Apothecium

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No Ascocarp (the naked Asci)Peach Leaf Curl
caused by Taphrina deformans
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Cleistothecia Powdery Mildew fungi
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Cleistothecia of Powdery Mildews
Note appendages on cleistothecium
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Blumeria
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Perithecia and Pseudoperithecia (pseudothecia)
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Cryphonectria (Endothia) parasitica
Causal agent of Chestnut blight

• Pimple like perithecia
• Ascospores forceably ejected

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Scabby barley kernels with perithecia of
Gibberella zeae.
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Pseudothecia of Cochliobolus heterostrophus
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Venturia inaequalis causal agent of Apple Scab

• Sub-cuticular growth of hyphae

• pseudothecium (specialized perithecium)

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Sordaria spp.
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ApotheciumSclerotinia sclerotiorum
2 apothecia emerging from a sclerotium
Asci with ascospores
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Source of Apothecia

• Frequently formed from sclerotia
• Sclerotia
• Composed of hyphae
• Hard pigmented cover rind
• Hyphae inside and protected by rind
• Overwinter well

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