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Introductory Mycology BOT 461/561

Introductory Mycology BOT 461/561. What are fungi?. Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their nutrition. Body Plan. unicellular ( yeast ), filamentous, or both (=dimorphic)

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Introductory Mycology BOT 461/561

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  1. Introductory Mycology BOT 461/561

  2. What are fungi? • Eukaryotic, spore-bearing, heterotrophic organisms that produce extracellular enzymes and absorb their nutrition.

  3. Body Plan • unicellular (yeast), filamentous, or both (=dimorphic) • Hypha (pl. hyphae) is the basic “cellular” unit in filamentous fungi; they may be septate or coenocytic (aseptate); collectively a mycelium • limited tissue differentiation and division of labor • somatic & reproductive structures • plectenchyma: all organized fungal tissue, somatic & reproductive

  4. Nuclear Status • Eukaryotic; uni, bi- or multinucleate • Haploid, diploid (less frequent) • Monokaryon (1 nucleus per hyphal compartment) • Dikaryon (2 nuclei per hyphal compartment) • Homokaryotic • Heterokaryotic

  5. Mitosis • intranuclear: nuclear membrane doesn't breakdown during mitosis • centric in flagellated forms; typical centrioles of eukaryotes • noncentric in nonflagellated forms; possess spindle pole bodies (SPBs); differ from centrioles in lacking microtubular component

  6. Organelles • typical eukaryote assemblage of organelles + fungal specific ones • mitochondria • endoplasmic reticulum • Golgi equivalents single cisternal elements • vacuoles • microbodies funx in fatty acid degradation, N metabolism

  7. Cell Wall Chitin • well defined • chitin 1-4 n-acetyal glucosamine • -glucans polymers of glucose 1-3 glucose • cellulose in some 1-4 glucose Cellulose  1-3 glucan chitin -glucans

  8. fungal specific organelles involved in cell wall growth • Spitzenkorper • associated with growing hyphal tips in septate fungi • chitosome • microvesicles transporting chitin synthases to growing cell wall

  9. Nutrition • Heterotrophic • Secrete extracellular enzymes • Absorptive nutrition • Saprobes: decay dead organic matter • pathogens: biotroph, necrotroph • symbionts: parasites - commensals - mutualists

  10. Spores - a minute propagative unit functioning as a seed, but differing from it in that a spore does not contain a preformed embryo Fruiting body- any complex fungal structure that contains or bears spores; a sporocarp

  11. Reproduction • Sexual reproduction: spores meiotically derived nuclei • Homothallic (selfing) • Heterothallic (outcrossing) • Monoecious or dioecious • Genetic mating system • MAT loci • 1 to hundreds of “sexes” • Asexual reproduction • Spores with mitotically derived nuclei

  12. Misc. • Life cycle: simple to complex; wide variety • Sporocarps: microscopic or macroscopic, limited tissue differientiation • Habitat: ubiquitous • Studied by mycologists!!!!!!

  13. What are fungi? • Eukaryotic, spore-bearing, heterotrophic organisms that produce extracelluar enzymes and absorb their nutrition.

  14. Fungi vs. "fungi" • Based on the phenotypic definitions or traits attributed to fungi, fungi do not comprise a single monophyletic group of organisms • more than one evolutionary origin • not all "fungi" are members of the Kingdom Fungi

  15. F UNGI (e.g., mushrooms, yeasts) M ICROSPORIDIA M ETAZOA (Animals) Phylogeny Of Eukaryotes D ICTYOSTELIDAE Slime molds M YXOGASTRIDAE L OBOSA A NGIOSPERMAE (Green Plants) based on DNA sequence data C HLOROPHYCEAE R HODOPHYTA G LAUCOPHYTA (some water molds Sudden Oak Death) O OMYCETES P HAEOPHYCEAE (Brown algae) C ILIOPHORA A PICOMPLEXA K INETOPLASTIDA E UGLENOIDEA A CRASIDAE V AHLKAMPFIIDAE P ARABASALLA D IPLOMONADIDA

  16. Some characters that separate the the Kingdom Fungi from “protistan fungi” Kingdom Fungi Protistan fungi mitochondria: cristae flattened cristae tubular motile cells: no motile cells or motile cells with anterior posterior flagellum or lateral heterokont flagella cell wall carbohydrate: glucans, chitin glucans, cellulose lysine biosynthesis: alpha-aminoadepic acid (AAA) diaminopimelic (DAP) storage compound glycogen mycolaminarins sterols ergosterol fucosterol Phyla: Chytridiomycota Oomycota (emphasized Zygomycota Myxomycota in class) Glomeromycota Dictyosteliomycota Basidiomycota Ascomycota

  17. General characteristics of the Phyla of the Kingdom Fungi • basal lineages • Chytridiomycota: (800) • unicellular to mycelial (coenocytic) • zoospore with single posterior whiplash flagellum • aquatic & terrestrial • no sporocarp production • Zygomycota: (1000) • generally coenocytic mycelium • production of zygosporangia & zygospores • no sporocarp production • Glomeromycota: (200) • formerly part of Zygomycota • coenocytic mycelium • no known sexual reproduction • arbuscular mycorrhizae (Glomerales) • no sporocarp production

  18. Basidiomycota: (22500) • septate mycelium • clamp connections • complex dolipore septa • dikaryotic, haploid mycelium • production of exospores (basidiospores) on a basidium • production of complex sporocarps • Ascomycota: (35000) • septate mycelium • simple septa • monokaryotic, haploid mycelium • production of endospores (ascospores) • in an ascus • production of complex sporocarps • often dominant asexual reproduction

  19. asci + ascospores Regularly septate hyphae basidia + basidiospores dolipore + clamp connections Phylogeny of Kingdom Fungi Chytridiomycota Chytridiomycota + Multiple losses of flagellum Zygomycota X Glomeromycota chitin* glycogen* mito cristae* ergosterol post smooth flagellum* *share with animals Ascomycota X Basidiomycota

  20. http://ocid.nacse.org/research/aftol/

  21. Fossil Record of Kingdom Fungi - How old are fungi? Silurian 440 hypha, spores ?Ascomycota Devonian 410 wood decay Basidiomycota mycorrhizae Glomeromycota zoosporangia Chytridiomycota Carboniferous 360 zygospores Zygomycota clamp connections Basidiomycota ?fruit bodies Permian 286 white rot Basidiomycota Triassic 245 wood decay Basidiomycota mycorrhizae Glomeromycota Jurassic 208 shelf fungus Basidiomycota Cretaceous 144 rusts Basidiomycota polypores conidia Ascomycota Tertiary 65 extant morphologies

  22. 3 Major Clades - Classes - of the Basidiomycota Hymenomycetes mushrooms, shelf fungi jelly fungi, coral crusts, puffballs Ustilaginomycetes smuts Urediniomycetes rusts, marine yeasts crusts

  23. Nomenclature Amanita muscaria Kingdom - Fungi Phylum - Basidiomycota Class - Hymenomycetes Order - Agaricales Family - Amanitaceae Genus - Amanita Species - A. muscaria

  24. Introductory Mycology BOT 461/561http://ocid.nacse.org/classroom/fungi/bot461/

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