Introductory Mycology BOT 461561

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Introductory Mycology BOT 461/561
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What are fungi?

• Eukaryotic, spore-bearing, heterotrophic
  organisms that produce extracellular enzymes and
  absorb their nutrition.

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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

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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

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• 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

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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

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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
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• 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

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Nutrition

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

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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
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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

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Misc.

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

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What are fungi?

• Eukaryotic, spore-bearing, heterotrophic
  organisms that produce extracelluar enzymes and
  absorb their nutrition.

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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

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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
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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 fucostero
l Phyla Chytridiomycota Oomycota (emphasize
d Zygomycota Myxomycota in class) Glomeromycota
Dictyosteliomycota
Basidiomycota Ascomycota
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• 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)

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• 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

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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
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http//ocid.nacse.org/research/aftol/
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Fossil Record of Kingdom Fungi - How old are
fungi?
Silurian 440 hypha, spores ?Ascomycota Devonian
410 wood decay Basidiomycota mycorrhizae Glo
meromycota zoosporangia Chytridiomycota Carbon
iferous 360 zygospores Zygomycota clamp
connections Basidiomycota ?fruit
bodies Permian 286 white rot Basidiomycota Tri
assic 245 wood decay Basidiomycota mycorrhiza
e Glomeromycota Jurassic 208 shelf
fungus Basidiomycota Cretaceous 144 rusts Basi
diomycota polypores conidia Ascomycota
Tertiary 65 extant morphologies
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3 Major Clades - Classes - of the Basidiomycota
Hymenomycetes mushrooms, shelf fungi jelly fungi,
coral crusts, puffballs
Ustilaginomycetes smuts
Urediniomycetes rusts, marine yeasts crusts
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Nomenclature
Amanita muscaria
Kingdom - Fungi Phylum - Basidiomycota Class
- Hymenomycetes Order - Agaricales Family
- Amanitaceae Genus - Amanita Species
- A. muscaria
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Introductory Mycology BOT 461/561
http//ocid.nacse.org/classroom/fungi/bot461/