Transcript Mycelium

Characteristics




Multicellular
Nonmotile
Cell wall
 made of chitin
Eukaryotic heterotrophs
 saprophytes
 live off decaying material / organisms
 parasitic
 disease causing
 symbionts
 lichen
Parasitic Fungi
Predatory fungus
A Variety of Roles

Pathogens
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Spoilers of food supplies
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Used to manufacture
 Antibiotics
 Cheeses
Structure of Fungi
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Mycelium
 multicellular
 feeding structure
 branching tubular cells
 hyphae
one cell (part
of one hypha of
the mycelium)
Mycelium
Mycelium
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Extracellular Digestion
 mycelium
 tips
grows into food source
of hyphae secrete digestive enzymes
 enzymes
break down organic material into
simple forms that can be absorbed by
hyphae
Fungal Life Cycle
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No motile stage
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Asexual and sexual spores produced
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Spores germinate after dispersal
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In multicelled species, spores give rise to
a new mycelium
Fungal Spores
Made up of one or a few cells
 Can resist dehydration
 Remain dormant until environmental
conditions favor germination
 Produced asexually or sexually
 Fungal classification is based on
type of sexual spores
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Types of Sexual Spores
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Club fungi make basidiospores on the
surface of a club-shaped cell (basidium)
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Sac fungi produce ascospores inside a
parent cell called an ascus
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Zygomycete hyphae fuse to produce a
thick-walled zygospore
Basidiomycota: Club Fungi
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Examples
 mushrooms
 taodstools
Club Fungi (cont.)
puffballs
wheat
rust
Club Fungi (cont.)
 portabella
 shittake
Club Fungi (cont.)
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Fruiting body
 structure that grow above ground
 has ability to remain dormant for many
years
Reproduction
 Cycle 1
 hyphal cells of two mating strains meet
 cytoplasm fuses to form dikaryotic
mycelium
 reproductive structure (basidiocarp)
forms
Club Fungi (cont.)
 Cycle
2
 spore-bearing structures form on
basidiocarp
 nuclei fuse to produce a zygote
 zygote undergoes meiosis to produce
haploid spores
 spores give rise to haploid mycelia
Club Fungus Life Cycle
Club fungus life cycle
Club Fungus Life Cycle
nuclear fusion
Diploid Stage
Haploid Stage
meiosis
Spores (n)
form
clubshaped
structures
with two
nuclei
(n + n)
gills
Spores released
cap
stalk
“dikaryotic” (n + n)
mycelium
Germination,
mycelium
forms
cytoplasmic
fusion
Ascomycota: Sac Fungi
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Broken into 2 groups
 sexual reproduction
 examples
Dutch Elm disease
Ergot
Sac Fungi (cont.)
 Yeast
 asexual
reproduction
 Examples
Penicillin
Ringworm (tinea)
Sac Fungi (cont.)
 Athletes
Foot (tinea)
 Plant diseases
 tomato blight
 black spots on
roses
Sac Fungi (cont.)
asexual spores called conidia
 sexual ascospores in sac-shaped cells call
asci
 multicelled species form reproductive
structures called ascocarps that enclose
the asci
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Sac Fungus
Sac fungi
diploid (2n) hyphal cell
Diploid Stage
Haploid Stage
nuclear
fusion
cytoplasmic
fusion
meiosis
in ascus
two A + two a
ascospores (n)
asexual
spores
asexual
spores
hyphae of
mating strain A
mitosis
hyphae of
mating strain a
four A + four a
ascospores
dispersal,
germination
Zygomycota
terrestrial organism
 rhizoids
root-like structures (hyphae)
 penetrate surfaces and anchor the
mold
 stolons
stem-like hyphae
 run across the surface
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Zygomycota (cont.)
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Examples
 Common molds
 Bread
 cheese
Zygomycota (cont.)
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A Zygomycete Life Cycle - 1
 sexual reproduction occurs, then hyphae of
mating strains meet
 at point of contact, hyphae form gametangia
Zygomycota (cont.)
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A Zygomycete Life Cycle - 2
 gametangia
tips fuse; form zygosporangium
 nuclei
inside zygosporangium fuse to
produce a diploid zygospore
 zygospore
 meiosis
spores
may remain dormant
of zygote nuclei produces haploid
Zygomycota Fungi
Zygomycete life cycle
Life Cycle of Rhizopus
zygospore (2n)
nuclear fusion
Diploid Stage
Haploid Stage
meiosis
spores
(n)
germinating
zygospore
a zygospore
young zygospore
spores
(n)
gametangia
fusing
contact between
hyphae of two
mating strains
b spore sac
mycelium develops
from germinated
spore
stolon
ASEXUAL
REPRODUCTION
(mitosis)
rhizoids
Fig. 24-6a, p.394
Lichens
Lichens
Lichen
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pioneering species
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ascomycete and cyanobacteria or green algae
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fungus composes bulk of the structure
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absorb mineral ions from substrates
 hostile
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environments
cyanobacteria-containing lichens can fix nitrogen
Mycorrhiza
“Fungus-root”
 mutualism between a fungus and a tree
root
 fungus gets sugars from plant
 plant gets minerals from fungus
 many plants do not grow well without
mycorrhizae
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Mycorrhizae
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Mutualistic fungus and tree roots
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Ectomycorrhizae
 Hyphae form net around roots
 Common in temperate forests
Endomycorrhizae
 Fungus actually enters root cell
 Form in 80% of vascular plants
 Zygomyetes are the fungal partners
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Mycorrhiza
Mycorrhiza