Kingdom Fungii
Protozoans
(heterotrophic protists)
• Division Myxomycota (acellular or
plasmodial slime molds)
• Division Acrasiomycota (cellular slime
molds)
• Division Oomycota (water molds or egg
fungi)
Myxogastrida (plasmodial slime molds)
(formerly Myxomycota latter is
supplement)
(a)Feeding stage consists of a motile,
multinucleated, amoeboid mass called a
plasmodium
(b)"If the habitat of a slime mold begins to dry up
or there is no food left, the plasmodium ceases
growth and differentiates into a stage of the life
cycle that functions in sexual reproduction."
Plasmodial slime molds,
like Physarum shown here,
are basically enormous
single cells with thousands
of nuclei. They are formed
when individual flagellated
cells swarm together and
fuse. The result is one large
bag of cytoplasm with
many diploid nuclei.
Dictyostelida (cellular slime molds) (formerly
Acrasiomycota latter is supplement)
(a)Unlike the plasmodial slime molds, the cellular
slime molds exist as free-living individual cells
that come together to form a multicelled slug
(rather than forming a multinucleated plasmodium
via multiple rounds of mitosis not followed by
cytokinesis as do the plasmodial slime molds)
(b) Individual cells resemble amoebas
(c)"The feeding stage of the life cycle consists of
solitary cells that function individually. When
there is no more food, the cells form an aggregate
that functions as a unit. Although the mass of
cells resembles a plasmodial slime mold, the
important distinction is that the cells of a cellular
slime mold maintain their identity and remain
separated by their membranes."
Oomycota (water molds)
(a) The Oomycota or water molds
superficially resemble fungi, but differ
from true fungi in a number of ways
including
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(i) Water molds have cellulose (not chitin) cell
walls
(ii) Water molds are flagellated at certain
points in their life cycle
(iii) Water molds are diploid throughout most
of their life cycle
"Oomycota" means "egg fungi," and refers to
the large round oogonia, or structures
containing the female gametes, as shown in
this picture of the common "water mold"
Saprolegnia. Oomycetes are oogamous,
producing large non-motile gametes called
eggs, and smaller gametes called sperm
Fungii
• Ancient Greeks and Egyptians used fungii to
make wine
• Myan Indian tribes of Mexico, hallucinogenic
mushrooms in religious ceremonies
• World War I, puff balls were used to cover
wounds
• Pathogens to humans, plants and other
organisms
• Environmental recyclers
Decomposers
•
•
•
•
Heterotrophic
Saprophytic
Excrete enzymes onto nutrient source
Absorb material
Fungal Structure
• Eukaryotic,
multicelllular
• Filaments (hyphae),
connected end to enc
• Diffuse connection of
cells, body of a fungii
is termed mycellium
• Reproductive hyphae
for the sporocap (cap
of the mushroom)
Fungal Cells
• In addition to being filamentous,
fungus may be coenocytic, no
distinction between individual cells.
• Long filaments with a cytoplasm lining
and a large vacuole in the center.
(zygomycetes)
• Others are septate,filaments are
separated by cross walls called septa
(ascomycetes and basidiomycetes)
Fungal Cells
Coenocytic
Septate
Hyphae grow at their
tips and branch to
form a mass of
interwoven strands
that is called
mycelium.
Fungal Mycelium
Ploidy
Fungi typically possess haploid nuclei,
except just prior to meiosis
Only following nuclear fusion
(karyogamy) are fungi diploid, and
mitosis in fungi does not occur in the
diploid state
However, many fungi routinely achieve a
diploid-like state following cytoplasmic
fusion (plasmogamy) that is called a
dikaryon state or stage; note that
dikaryon is not synonymous with diploid
since nuclei remain haploid even if found
in same cytoplasm
Plasmogamy
Though fungi nuclei are typically
haploid, that doesn't stop haploid
nuclei from different fungal parents
(e.g., mom and dad equivalents) from
being present in the same cytoplasm
The process by which the cytoplasms
of two parental fungi fuse is called
plasmogamy
Note that plasmogamy may be
followed by nuclei fusing, though this
does not necessarily occur
immediately, and for some fungi the
time until nuclear fusion occurs can be
greatly extended (days, months, years)
Dikaryon state or stage
The post-plasmogamy condition in
which two different haploid nuclei
occupy the same cytoplasm is a
dikaryon state or stage
Being a dikaryon, since cytoplasms
are shared, provides the masking of
deleterious alleles of diploidy without
the possession of diploid nuclei
Karyogamy
The fusion of haploid nuclei found in
dikaryonic fungal cells is called
karyogamy
Karyogamy is necessary for the
occurrence of meiosis (since haploid
nuclei cannot undergo meiosis)
Note that meiotic products are both
haploid and therefore are no longer
dikaryonic
Sexual reproduction (note: order of terms is relevant):
mitosis
Hyphae (ploidy = n)
mitosis
Mycelium (ploidy = n)
Plasmogamy (a process) (= fusion of cytoplasm)
Dikaryotic stage (ploidy = n + n) (occurs within
zygosporangia for Zygomycete, ascogonia for Ascomycete,
or hyphae for Basidiomycete)
mitosis
Karyogamy (a process) (= fusion of haploid nuclei)
Diploidy (ploidy = 2n) (occurs within zygosporangia for
Zygomycete, ascocarps for Ascomycete, or basidiocarps for
Basidiomycete)
Meiosis (a process)
Spore-producing structures (ploidy = n) (= sporangium for
Zygomycete, asci for Ascomycete, or basidia for
Basidiomycete)
Spores (ploidy = n) (= spores for Zygomycete, ascospores
for Ascomycete, or basidiospores for Basciomycete)
Germination (a process)
mitosis
Hyphae (ploidy = n)
mitosis
Mycelium (ploidy = n)
Sexual Reproduction
Asexual reproduction (note: order of terms is
relevant):
mitosis
Hyphae (ploidy = n)
mitosis
Mycelium (ploidy = n)
mitosis
Spore-producing structures (ploidy = n)
mitosis
Spores (ploidy = n) (= conidia for sac
fungi)
Germination (a process)
mitosis
Hyphae (ploidy = n)
mitosis
Mycelium (ploidy = n)
Placement into a division is based on the way in which the fungus reproduces
sexually. The shape and internal structure of the sporangia, which produce
the spores, are the most useful character for identifying these various major
groups.
There are also two conventional groups which are not recognized as formal
taxonomic groups (ie. they are polyphyletic
Club Fungi
(Basidiomycota)
latticed stinkhorn
Species in this phylum
produce spores on a
club-like structure
called the basidium
Produce spores on exposed surfaces -releasing the spores gradually through
structures such as pores or gills.
Division Basidiomycota
(club fungi, mushrooms)
Members of Division Basidiomycota are
also called the club fungi and include the
mushrooms
Mushrooms are fruiting bodies of
underground mycelia
Club fungi spend most of their life cycle in
the dikaryotic state
Basiodospores (mushroom gill)
Basidiospores
Sac Fungi (Ascomycota)
Sac fungi produce spores inside cases (asci) which
may open at one end.
White Morel (Morchella deliciosa, left),
however, is often found in urban
locations growing among leaves or
other discarded stuff.
Another prominent
group of Ascomycota
is the Cup Fungi
The mushrooms of these fungi look like little cups
or sacs and often do not have a stalk at all. An
exception to this is the brightly colored Stalked
Orange Peel Fungus (Aleuria rhenana).
In hyphal
Ascomycota, the
youngest,
terminal hyphal
segments
develop into 8spored
asci.
Ascomycota are either single-celled
(yeasts) or filamentous (hyphal) or both
(dimorphic). Yeasts grow by budding or
fission and hyphae grow apically and
branch laterally. Most yeasts and
filamentous Ascomycota are haploid, but
some species, Saccharomyces cerevisiae
for example, can also be diploid.
Mitospores may simply reproduce the
parent, or may also act as gametes to
fertilize a compatible partner.
Conidia
Conjugation Fungi (Zygomycota)
The best known of this
phylum of around 600
species is black bread
mold, such as Rhizopus
stolonifer.
Division Zygomycota (zygote fungi)
These are the zygote
fungi
In their sexual cycle
these fungi form
gametangia that are
multinucleated cells
walled off from parental
cells by septa
Gametangia from two
different parental fungi
fuse (undergo
plasmogamy) to form
dikaryonic
zygosporangia that are
capable of toughening to
form a dormant stage
Zygosporangia give rise to
sporangia following germination,
karyogamy, and meiosis
Imperfect Fungi (Deuteromycota)
Around 25,000 additional fungus species are
grouped in this phylum -- these species are
the "left-overs" that don't fit well into any of
the other groups. Members include
Trichophyton (Athlete's foot), Penicillium
(Penicillin), and Candida albicans ("Yeast"
infections).
Imperfect fungi
Imperfect fungi fail to reproduce
sexually, consequently fail to produce
the sexual structures by which other
fungi are classified (at least
traditionally), so are not well
phylogenetically classified, at least
using classical methods
Hyphae
Lichens
Lichens
Lichens are a polyphyletic grouping of fungi that
possess algae (eukaryotic or blue-green)
symbionts
"The fungus usually gives the lichen its overall
shape and structure, and tissues formed by
hyphae account for most of the lichen's mass…
The alga always provides the fungus with food.
Cyanobacteria in lichens fix nitrogen and provide
organic nitrogen. The fungus provides the alga
with a suitable physical environment for growth.
Lichens absorb most of the minerals they need
either from air or in the form of dust… Fungal
pigment shades the algae from intense sunlight.
Some fungal compounds are toxic and prevent
lichens from being eaten by consumers."
Crustose Lichens
Crustose lichens are flaky or crust-like. They can
be found covering rocks, soil, bark, etc. -- often
forming brilliantly colored streaks.
The yellow ones pictured here on a granite stone
in the Rocky mountains, are probably Common
Yolk Lichens (Acarospora spp.); the red,
Caloplaca spp.; and green, Lecanora spp.. The
little buttons to the left are a magnification of the
red streaks above.
Foliose Lichens
Foliose (leaf-like) lichens can be papery thin or,
in more advanced forms, netted branch-like.
Branched foliose lichens have a distinct top and
bottom surface, thus differentiating them from
most fruticose lichens. This can be seen clearly
in the Pseudocyphellaria anthraspis photo,
above left; the Hypogymnia imshaugii on the
right has a puffed body with a black
undersurface.
Fruticose Lichens
Fruticose lichens are the
most highly developed lichens. Their branches
are much closer in form to "true" branches
although, unlike most plants, the lichen branch
has no specialized vascular system for
transporting fluids.
The British Soldier Lichen (Cladonia macilenta),
left, is one of the showiest fruiting lichens: even
though the mushrooms are quite tiny, their
bright color and distinctive form makes them
stand out in their forest habitat.
Old Man's Beard