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Review from last time…

Review from last time…. Haploid? Diploid? Dikaryon? . Cellular state?. Nuclear state?. Teleomorph Anamorph Holomorph “Deuteromycetes”: a p ractical taxonomic strategy to deal with an alternative lifestyle. Sexual (perfect) state Asexual (imperfect) state Asexual+sexual life cycle.

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Review from last time…

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  1. Review from last time… • Haploid? • Diploid? • Dikaryon? • Cellular state? • Nuclear state?

  2. Teleomorph Anamorph Holomorph “Deuteromycetes”: a practical taxonomic strategy to deal with an alternative lifestyle Sexual (perfect) state Asexual (imperfect) state Asexual+sexual life cycle More definitions

  3. Deuteromycetes – life without sex

  4. 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

  5. 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)

  6. Deuteromycetes – life without sex • Does this mean no genetic recombination? NO! ... • But recombination requires an inventive lifestyle ...

  7. Deuteromycetes – life without sex • Does this mean no genetic recombination? NO! ... • But recombination requires an inventive lifestyle ... • Parasexuality mirrors the sexual cycle

  8. Parasexual cycle part 1 heterokaryon formation Hyphal fusion is common Mutation is rare Heterokaryons are hyphae with two types of nuclei in any ratio

  9. Heterokaryon sporulation • Each nucleus can act independently in a heterokaryon

  10. Karyogamy • Fusion of nuclei is rare, 1 in 106 • Creates a diploid nucleus • Isolate by fast growth in minimal agar suspension • Forced diploids are stable on minimal medium

  11. Haploidization is common, 1 in 103 diploid nuclei

  12. 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

  13. Ecological relationships involving fungi

  14. Ecological roles of fungi • Saprobes • Mycorrhizae • Pathogens • Parasites

  15. Amphibious fungi • Major role in recycling terrestrial inputs into aquatic systems • Leaf fall • ‘Conditioning’ plant material for animal consumption

  16. Ingoldian spores are found in highly oxygenated water

  17. Ingoldian spores are typical of highly oxygenated waters

  18. Beverwykella Aeroaquatic fungi in still water

  19. Beverwykella Helicoon

  20. Competition between fungal individuals can produce barrage lines

  21. Another fungus  insect connection

  22. 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

  23. 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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