Domain EukaryaThe Fungi (What a
fun guy!)
The Kingdom Fungi is in
the domain Eukarya and in
the supergroup Unikonta.
They are in the group
Opisthkonta with animals.
Both groups have different
unicellular organisms that
are their common ancestor.
That fact indicates the
groups became
multicellular organisms
independent of one another.
Most closely related protists group to the fungi are
nucleariids. Nucleariids are amoeboid organisms, with fine
pseudopodia unsupported by microtubules, with or without
hollow siliceous plates or spheres or spines, the walls of
which are a meshwork. Some are uninucleate but others are
multinucleate. No flagellated stages known. Mostly described
from soils or freshwater
There are indications that the ancestor to the fungi was a
flagellated, unicellular eukaryote. Most fungi no longer have
any flagellated cells except the chytrids.
Fungi-are mostly multicellular heterotrophs that obtain their
nutrients by absorption (saprophytes – decomposers - or
parasites). Fungi must secrete enzymes to break down the
nutrients before the nutrients are absorbed.
Most fungi exhibit a haploid lifecycle with sexual and asexual
reproduction, however there are some fungi that only
reproduce asexually or only sexually. .
Fungal morphologyMulticellular fungi grow in cellular threads called hyphae.
A mass of
hyphae is a
mycellium.
Some fungi
when
reproducing
sexually, will
organize into
fruiting bodies
such as
mushrooms.
Except for
Chytrids
All fungi produce spores (asexually or sexually) in order to
reproduce.
The cell walls
of hyphae are
made of
chitin not
cellulose.
Chitin
contains
nitrogen
cross-links
between
glucose
rings.
There are two general types of hyphae-1. Hyphae that have
cross walls forming individual cells. Walls have pores so that
material can move between cells. Higher fungi have septate
(walled) hyphae. 2. Nonseptate fungi do not have cross walls
and are multinucleate. Lower fungi are nonseptate fungi.
Cross Walls of Hyphae
Hyphae where the nuclei of
each cell are embedded in the
cytoplasm without a cell wall
or septum separating
individual cells
Eg. Zygomycota, Oomycota
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Hyphae with septa or cross
walls to separate individual
cells
Eg. Basidiomycota,
Ascomycota
Specialized hyphae actually
can form loops to kill prey.
Haustoria are specialized
hyphae sending structures
into cells to absorb nutrients.
Many fungi can reproduce
asexually and also sexually.
Most fungi are haploid. Since
there are no flagellated
gametes, two different mating
types of hyphae (+, -) join
(plasmogamy). When that
occurs, quite often the nuclei
remain distinct (dikaryon
state n+n). Eventually the
nuclie fuse (karyogamy)
Fungi Nutrition
• Extracellular digestion
Digestive enzymes are
secreted into the food
source
Digested food is
absorbed into the
mycelium
Notes
FEEDING RELATIONSHIPS
– Saprophytes = decompose dead organic materials
– Mutualists = live together with another species & both
benefit
• Lichen = fungus and algae together
• Mycorrhizae = fungus in plant roots
– Parasite = live off living host cell
• Haustoria = specialized hyphae penetrate the host cell and
grow in it absorbing its nutrients
Mycorrhizae
Mycorrhizae means “fungus-root”;
mutualistic relationship between
plant and fungi
The plant photosynthesizes while
the fungus more efficiently takes
up nutrients and water from the
rhizosphere than the roots would
alone.
Plant benefits include:
•Improved nutrient/water
uptake
•Improved root growth
•Improved plant growth and
yield
•Improved disease resistance
•Reduced transplant shock
•Reduced drought stress
Beneficial Fungi
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Yeast
Mushrooms
Morels
Truffles
food
• Penicillin- medicine
• Saprophytes
(decomposers)
• Mutualists (live in
symbiotic
relationships which
benefit both species)
Non-beneficial Fungi
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Rusts
Rhizopus Black bread mold
Puffballs
Toadballs
Toadstool
Ringworm
Tomato blight
Cucumber scab
Athlete's foot
3 types of asexual reproduction of fungi
Notes
1. fragmentation = hyphae broken off a mycelium
will grow into a new mycelium
2. budding = after mitosis, a new individual pinches
off from the parent
EX. Yeast
3. spores = specialized hyphae form a sporecontaining sac called a sporangium; spores are
small and lightweight; spores can be dispersed
by wind, water, and animals; grow into new
fungus
Sexual Reproduction - fertilization or fusion of the parent
nuclei occurs (karyogamy). Meiosis occurs shortly after
fertilization restoring the haploid state. General outline of
fungi reproduction
Phylum Chytridiomycota or Chytrids-Most primitive fungi.
Has flagellated spores (zoospores). Molecular evidence
along with chitin found in the cell walls indicate that
chytrids are fungi. Most species are aquatic. Some species
are unicellular, but most are aseptate. Most are saprophytes
Kingdom Fungi – 4 Major Phyla
1. Phylum Zygomycota = the Bread Molds
Rhizopus – black bread mold
2. Phylum Ascomycota = the Sac Fungi
Yeast, morels, truffles
3. Phylum Basidiomycota = the Club Fungi
Mushrooms, puffballs, bracket fungi, rusts, smuts,
toadstools
4. Phylum Deuteromycota = the Fungi Imperfecti
Phylum Zygomycota
Bread Mold
Zygomycota (Rhizopus) the
Common Molds
-are primarily decomposers
-asexual spores may be produced in sporangia
-sexual reproduction occurs between + and – strains forming
a 2n zygote; a zygospore develops and may lie dormant for a
long period of time; meiosis occurs just before germination
-only the zygote is diploid; all hyphae and asexual
spores are haploid
Zygomycota – common molds
The fungal mass of
hyphae, known as the
MYCELIUM
penetrates the bread
and produces the
fruiting bodies called
sporangia on top of
the stalks
Mycelia = a mass of hyphae or
filaments
Rhizoids = root-like hyphae
The zhizoids meet underground and mating occurs between
hyphae of different molds (SEXUAL REPRODUCTION)
Zygomycota (Rhizopus)
Lifecycle of a Zygomycete Fungi – Asexual then Sexual
Bread Mold Sporangia
The Phylum
Zygomycota
(molds) is a
lower fungi.
Reproduction is
asexual and
sexual. The
hyphae is
coencytic.
During asexual
reprodcution an
aerial hyphae
emerges to
form a sporangium. Mitosis occurs to form spores. The
sexual life cycle is the haploid life cycle. Two different
mating hyphae (+,-) are attracted and join. It forms a
gametogania with several haploid nuclei. They fuse to
form a zygosporangia (fertilization) which is very resistant to
drying out. Inside the zygosporangia the diploid nuclei under
go meiosis to produce haploid spores that are released.
Phylum Glomeromycota is a lower fungi that forms symbiotic
relationships with the roots of many plants. The fungi form
arbuscular mycorrhizae that push into plant root cells. The
plant cells provide food for the fungi and the fungi absorb
nutrients (phosphate and nitrates) and provide them to the
plant.
Mycelia of an arbuscular
mycorrhizal fungus emerge from a
root; the spherical bodiesare
vesicles (fungal storage organs).
*Arbuscular mycorrhizae penetrate
root cells, ectomycorrhizae form
sheaths and do not penetrate the
root cells.
Higher fungi are
those fungi that
form septate cells
and individual
cells. Phylum
Ascomycota (sac
fungi) are fungi
that produce
sexual haploid
spores in
structures called
asci (ascus
singular). After
meiosis, mitosis takes place so 8 spores are produced in the
ascus. The asci are found on fruiting bodies called
ascocarps. Most ascomycetes can also undergo asexual
reproduction on aerial hyphae (condiophores). Yeast and
morels are also ascomycetes.
Examples of
ascomycota
Phylum: Asocomycota
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Yeast
truffles
morels
sac fungi
Cup Fungi – Ascomycete Fungi
Note the cup shapes and
orange peel colour
Yeast is an Ascomycete Fungus
Truffles are round, warty, fungi that
are irregular in shape. They vary
from the size of a walnut to that of a
man's fist. Since the times of the
Greeks and Romans these fungi
have been used in Europe as
delicacies, as aphrodisiacs, and as
medicines. They are among the
most expensive of the world's
natural foods, often commanding as
much as $250 to $450 per pound.
Truffles are harvested in Europe with the aid of female pigs or truffle
dogs, which are able to detect the strong smell of mature truffles
underneath the surface of the ground. The female pig becomes excited
when she sniffs a chemical that is similar to the male swine sex
attractant. The use of dogs to find truffles is also and option.
Morels are Ascomycete Fungi
Lichens are organisms with a symbiotic relationship
between fungi (mostly ascomycota) and green algae or
cyanobacteria. But the fungi have been known to harvest
the algae which is a case of enslavement not mutualism.
Known to be the pioneer species in primary succession
breaking down rock. Lichens are classified according to
structure.
Lichens
• Green scale-like patches on rock and trees
• Symbiotic partnership
– fungus (water, minerals)
– cyanobacteria (photosynthesis)
• soil builders
• Survive in harsh environments
Lichens
Lichens are mutualistic symbiotic
organisms between an ascomycote
fungus and a photosynthetic green
alga or cyanobacterium.
Lichens need only light, air, and
minerals to grow.
Pioneer species in many areas
Fruticose
Crustose
Foliose
Soredia are the asexual reproductive part of lichens,
containing both symbionts. Rhizines may be present to
anchor the lichen. Notice the distinctive algal layer
and the fungal layer present in the above illustration.
•Lichens are also dye sources, and is
used as a food-coloring agent and to
form litmus, the acid-base indicator.
•In arctic and alpine regions,
lichens serve as food for caribou,
reindeer and other mammals.
Phylum Basidiomycota
An example of Fungi You know
Mushrooms – “Club Like” Fungi or Basidiomycete Fungi
Basidiomycete or Club Fungi
Bracket Fungi – Basidiomycete Fungi
Puffball mushroom releasing
spores
Bracket Fungi
Puff Balls
Basidiomycete Fungi that all
produce Basiospores
Jelly Fungi
Mushrooms
Fungi can also cause disease such as smut on corn, rust on
maple leaves and ergots on wheat.
Other Basidiomycetes Rusts and
Smuts
Rust
infecting
wheat leaves
Rust infecting
a Leaf
Whitrot Smut
digesting old wood
Phylum
Basidomycota
(club fungi) are
fungi that
produce sexual
haploid spores
on a structure
called basidium.
Two different
mating types
hyphae are
attracted and
fuse forming a
dikaryon state.
The hyphae go in to form fruiting bodies called basidocarps
(mushrooms, puffballs etc.) Within the basidocarp, club-like
cells form called basidium (basidia pl.). The dikaryon state
fuses to become
diploid. Meiosis
occurs to
produce four
haploid spores
or basidiospores.
Phylum Deuteromycota
(Imperfect Fungi)
-Regarded as imperfect because they exhibit no sexual stage
-Members are not closely related and are not necessarily similar
in structure or appearance; do not share a common ancestry,
polyphyletic = coming from many ancestors
Deuteromycota – the Fungi
Imperfecti
• Resemble Ascomycetes,
but their reproductive
cycle has never been
observed
• Different from
Ascomycetes because
there is a definite lack of
sexual reproduction,
which is why they are
called Imperfect Fungi
Penicillium fungi
Up Close
Penicillin Mold
Deuteromycetes are called the imperfect fungi because they
do not have sexual phase. If their method of sexual phase is
discovered, they are reclassified into one of the fungal
phyla. Most imperfect fungi have been discovered to an
ascomycete.
Notes
Fungi Division
Examples
Type of
Reproduction
Characteristics
Zygomycotes
Bread mold
Rhizopus – a dung
fungus
Asexual – spores in
sporangium
Sexual – zygospores
are thick-walled spores
that can survive harsh
conditions; occurs
when two haploid
hyphae called
gametangium fuse
together to make a
diploid zygote
Do not have septa that divide hyphae into
individual cells
Stolons= hyphae that run along the surface of
bread
Rhizoids= penetrate food to absorb nutrients
Molds
Morels & truffles
Yeasts ( used to
produce alcohol, bake
breads, & genetic
engineering)
Asexual – chains or
clusters of asexual
spores called conidia
develop from the tip of
conidiophores
Sexual – ascospores
develop in an ascus
yeast = unicellular sac fungi
Mushrooms
Puffballs
Stinkhorns
Bird’s nest fungi
Bracket fungi
Rust
Smut
Asexual – spores on
conidiosphore called
conidia
Sexual - Basidiospores
produced in clubshaped hyphae called
basidia
most of the fungus is underground and not
visible
Penicillium notatum
Bleu cheese
Athlete’s foot
Tomato Blight
Asexual only
Conidiophores which
produce conidia
Many are used to flavor foods
penicillin
Sporangium fungi
Ascomycotes
Sac fungi
Basidiomycotes
Club fungi
Deuteromycotes
Imperfect Fungi
Septa in hyphae