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Dikaryomycota

Dikaryomycota. Persistent dikaryon: cells with two haploid nuclei Regularly septate hyphae. S. M. G2. G1. Dikaryomycota – two haploid nuclei. Haploidy  nuclear condition, referring to number of chromosome copies per cell in G1. Dikaryomycota – two haploid nuclei.

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Dikaryomycota

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  1. Dikaryomycota • Persistent dikaryon: cells with two haploid nuclei • Regularly septate hyphae

  2. S M G2 G1 Dikaryomycota – twohaploid nuclei Haploidy  nuclear condition, referring to number of chromosome copies per cell in G1

  3. Dikaryomycota – twohaploid nuclei Nuclei: HaploidDikaryoticDiploid plasmogamy karyogamy ?

  4. Dikaryons in fungi • Only one cell – Zygomycetes • Limited dikaryon – Ascomycetes • Persistent dikaryon – Basidiomycetes

  5. dikaryon monokaryon

  6. Maintaining the dikaryon state • Conjugate mitosis – coordinated nuclear division • Typically at “clamp connections” that have specialized septa

  7. Simple septum vs Dolipore septum

  8. Dikaryomycete classes based on sexual sporulation • Ascomycetes  in sacs • Basidiomycetes  on stalks

  9. Ascomycete life cycle Asexual cycle: haploid spores (n) +/– mating types septate hyphae (n)

  10. Ascomycete life cycle, Raven 15-14 Asexual cycle: haploid spores (n) +/– mating types septate hyphae (n) Mating structures: ascogonium trichogyne antheridium plasmogamy Trichogyne growth Nuclear migration

  11. Ascogonia andantheridia T An As

  12. Ascus development germination crozier meiosisII meiosisI mitosis (sp dep) karyogamy 2n

  13. Ascus formation penultimate cell  karyogamy Crozier = hook Meiosis and mitosis in developing ascus

  14. Ascus development karyogamy meiosisI meiosisII mitosis

  15. Ascomata: four types Emericella Erysiphe Peziza Morchella Neurospora Magnaporthe Cochliobolus Note ascus shape: elongate vs spherical

  16. Elongate asci: 2 types unitunicate bitunicate operculum Cleistothecial asci pore

  17. Otidea Asci and ascospores Peziza Eurotium

  18. dikaryotic ascogenous hyphae (n+n) Ascogonium croziers Sterile Hyphae (n) Ascogonium Ascoma development

  19. Ascomycete fruiting bodies: ascomata apothecium perithecium

  20. Mycosphaerella pseudothecia

  21. Erysiphe graminis

  22. septa Holobasidia Heterobasidia Synchronous spore formation Asynchronous spore formation basidiospore sterigma Nuclei migrate through the sterigma/spore junction

  23. Mushroom life cycle 15-19 Dikaryotic hyphae Basidiomata initiation is triggered by environmental conditions, including moisture

  24. Mushroom development Hymenium – fertile layer Mushroom hymenium on: _____, _____, _____

  25. Gilled mushrooms Agaricales Lactarius indigo

  26. Pores are lined with basidia

  27. Fomes fomentarius

  28. Auriscalpium vulgare Hydnum repandum

  29. Deuteromycetes – life without sex

  30. Deuteromycetes – life without sex • Advantages • speed (of reproduction, ~1 day) • flexibility (can maintain a well-adapted genome) • can maintain (lethal?) mutations in haploid nuclei, since hyphae are multinucleate

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