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Published byLaura Miller Modified over 9 years ago
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Review from last time… Haploid? Diploid? Dikaryon? Nuclear state? Cellular state?
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More definitions Teleomorph Anamorph Holomorph “Deuteromycetes”: a practical taxonomic strategy to deal with an alternative lifestyle Sexual (perfect) state Asexual (imperfect) state Asexual+sexual life cycle
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Deuteromycetes – life without sex
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What is a Deuteromycete? Formerly called Fungi Imperfecti Many common mold fungi do not have a known sexual life cycle Asexual state of a (typically) ascomycete fungus Also many zygomycetes and some basidiomycetes
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Deuteromycetes – life without sex Advantages – speed (of reproduction, ~1 day) – flexibility (can maintain a well-adapted genome) –For experimenters and future evolution can maintain mutations in haploid nuclei (hyphae are multinucleate)
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Deuteromycetes – life without sex Does this mean no genetic recombination? NO!... But recombination requires an inventive lifestyle...
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Deuteromycetes – life without sex Does this mean no genetic recombination? NO!... But recombination requires an inventive lifestyle... Parasexuality mirrors the sexual cycle
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Parasexual cycle part 1 heterokaryon formation Hyphal fusion is common Mutation is rare Heterokaryons are hyphae with two types of nuclei in any ratio
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Heterokaryon sporulation Each nucleus can act independently in a heterokaryon
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Karyogamy Fusion of nuclei is rare, 1 in 10 6 Creates a diploid nucleus Isolate by fast growth in minimal agar suspension Forced diploids are stable on minimal medium
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Haploidization is common, 1 in 10 3 diploid nuclei
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Horizontal genetic transfer Uptake of exogenous DNA Sources in nature anastomoses between closely related eumycotan fungi Heteroplasmons and heterokaryons Exploited for cell, genetic and biotechnology research
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Ecological relationships involving fungi
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Ecological roles of fungi Saprobes Mycorrhizae Pathogens Parasites
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Amphibious fungi Major role in recycling terrestrial inputs into aquatic systems Leaf fall ‘Conditioning’ plant material for animal consumption
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Ingoldian spores are found in highly oxygenated water
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Ingoldian spores are typical of highly oxygenated waters
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Aeroaquatic fungi in still water Beverwykella
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Helicoon
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Competition between fungal individuals can produce barrage lines
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Another fungus insect connection
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There’s no place like dung Major source of processed plant material Mastication, addition of lipids, vitamins, protein About 90% energy in herbivore dung is not utilized by the animal
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Dung successions Recycle nutrients Basis of another food web fungi to invertebrates Succession of fungal groups: zygomycete ascomycete basidiomycete –Nutrient assimilation? –Time to sporulation? even spore distribution
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