3. Mycologists, scientists who specialize
in the study of fungi, believe there are
a million or more species of fungi.
Scientists believe they have identified
only 5% of all fungi.
7. Fungi cell walls are made mostly of
the carbohydrate chitin.
Fungi can reproduce sexually and
asexually.
Kingdom Fungi is more related to
Kingdom Animalia than Kingdom
Plantae.
Kingdom Fungi & Kingdom Animalia
probably diverged from a common
ancestor some 0.6 billion years ago.
8. Fungi cell walls are made mostly of
the carbohydrate chitin.
Chitin can be found also in
exoskeleton insects
The storage carbohydrate of fungi is
called glycogen.
Glycogen can be found also in
muscles.
9. Fungi Reproduction
Dikaryotic Stage – the coexistence of
two different mating types of nuclei
which is unique to fungi.
10.
11. Plasmogamy
is a stage in the sexual reproduction of fungi.
In this stage, the cytoplasm of two
parent mycelia fuse together without the
fusion of nuclei, as occurs in higher terrestrial
fungi. After plasmogamy occurs, the
secondary mycelium forms. The secondary
mycelium consists of dikaryotic cells, one
nucleus from each of the parent mycelia. It is
the fusion of protoplasm between two motile
or non-motile gametes. It involves the union of
two protoplast bringing two haploid nuclei
close together in the same cell...
12. Karyogamy
Karyogamy is the fusion of pronuclei of two cells, as
part of syngamy, fertilization, or true bacterial
conjugation.
It is one of the two major modes
of reproduction in fungi. In fungi that lack sexual
cycles, it is an important source of genetic
variation through the formation of somatic diploids.
The term comes for the Greek karuo- (from karuon)
meaning nut and -gamos meaning marriage.It is
mainly found in fungal phylum ascomycetes. Species
that use this mode of reproduction is responsible for
causing ringworm.
13. Four groups of fungi according to their
molecular structures and sexual
reproduction:
Chytrids
Zygomycetes
Ascomycetes
Basidiomycetes
14. Chytridiomycetes
Members of the fungi phylum are
considered to be the most primative
fungi and probably appeared about
500 million years ago.
Chytrids, as member of this group are
known, are found anywhere.
15. Chytrids
Microscopic and differ from other fungi
phyla because chytrids produce motile
spores called zoospores.
Synthesize and release digestive
enzymes that break down molecules
in the protective covers of other
organisms.
Anaerobic chytrids are chytrids that do
not need oxygen.
16.
17. Zygomycetes
Include a variety of fungi. The black
bread mold is a common
zygomycetes. It decomposes
bread, fruits, vegetables, and
decaying animals, and produces a
fuzzy, black growth within the
substance
18. All the fungi assigned to this group (which probably does not
represent a single clade) form spores in a sporangium.
Some notable examples:the bread mold, Rhizopus
stolonifera
Rhizopus oryzae, used to make sake, the rice wine of Asia.
Can also infect humans, especially if they are
immunosuppressed (e.g., AIDS patients, transplant
recipients).
Another species of Rhizopus is used in the commercial
production of glucocorticoids.
Many mycorrhizal fungi belong to this group.
19.
20. Ascomycetes
Commonly called ―sac fungi‖ or ―cup
fungi‖ for the cup-shaped fruiting
bodies of many ascomycetes, this
group includes many delicious, edible
fungi.
There are some 30,000 known
ascomycetes, about 500 species of
which we called yeast. Yeasts
reproduce asexually by budding. Most
yeasts are singled-celled but some are
multi-cellular.
21. Ascomycetes produce two kinds of spores:asexual spores called conidia
ascospores produced following sexual reproduction. Four or eight ascospores develop inside a
saclike ascus (the group is commonly called sac fungi).
Some notable examples:Saccharomyces cerevisiae one of the budding yeasts. It ferments
sugar to ethanol and carbon dioxide [Discussion] and thus is used
◦ to make alcoholic beverages like beer and wine
◦ to make ethanol for industrial use
◦ in baking (it is often called baker's yeast). Here, it is the carbon dioxide that is wanted (to make bread and cakes "rise" and
have a spongy texture).
Yeast is also used
◦ in the commercial production of some vitamins.
◦ in the production — using recombinant DNA technology — of some human therapeutic proteins.
Neurospora crassa, another favorite "model" organism in the laboratory.
The fungal partner in most lichens is an ascomycete.
Powdery mildews that attack ornamental plants
The chestnut blight, which in a few decades killed almost all of the mature American chestnut
trees in the Appalachians of North America.
The Dutch elm disease, which has killed many of the American elms in the United States.
Pneumocystis jirovecii, which is a major cause of illness in immunosuppressed
people, e.g., patients with AIDS.
The truffle and the morel, both highly-prized food delicacies. The photo (courtesy of the
French Embassy Press & Information Division) shows a farmer from the Périgord (in
southwestern France) admiring a truffle. Truffles establish a symbiotic relationship with the
roots of such trees as oaks.
22.
23. Basidiomycetes
Most mushrooms, shelf fungi, and
puffballs belong to the fungi phylum
called basidiomycetes.
Basidiomycetes are the most familiar
of the fungi. Also called ―club
fungi‖, they account for about a third of
all identified fungi.
Almost 25,000 basidiomycete species
have been identified.
24. Basidiomycetes include mushrooms, shelf fungi, puffballs, rusts, and smuts. They
are dispersed by spores borne at the tips of basidia (giving rise to the name for the
group).
Mushrooms are masses of interwoven hyphae growing up from the main mass of the
mycelium growing underground. The basidia develop on the undersides and release
their spores (four from each basidium) into the air.
A single mycelium may expand outward year after year as its hyphae grow into new
terrain. In some species, mushrooms are sent up once a year at the periphery
producing a circle known since medieval times as a "fairy ring".
Some notable basidiomycetes:Armillaria bulbosa. A single specimen in northern
Michigan (USA) was found to have spread over 37 acres (15 hectares) of the forest
floor. RFLP analysis of samples taken from many different locations within this area
showed that all the samples were from a single clone. Assuming the normal rate of
vegetative growth for this species, it must have taken 1500 years to spread to that
size.
the cultivated, edible mushroom that finds its way into pizza, soups, etc.
Amanita muscaria. Forms a beautiful mushroom but deadly when eaten.
Smuts. Parasites of important crops like wheat, oats, and rye.
Rusts. Some, such as
◦ wheat black stem rust (Puccinia graminis) and
◦ white pine blister rust
are serious pests. Both have complicated life cycles during which they pass through
25.
26. Most of the fungi body is
mycelium, the mass of hyphae that
contains the vegetative part of a
fungus.
It reproduce asexually by
fragmentation and conidia spore
formation.
27.
28. Lichens
Lichens are fungi that live in a symbiotic association
with an autotrophic green alga or cyanobacterium (the
"photobiont") or — in some cases — both.
The fungal partner (the "mycobiont") in most lichens
(98% of them) is an ascomycete. Zygomycetes make
up the remainder.
The relationship is often characterized as mutualistic;
that is, both partners benefit. But recent evidence (e.g.
in British soldier) suggests that while the fungus is
dependent on its autotrophic partner, the photobiont is
often perfectly content to live alone.
Lichens secrete a variety of unusual chemicals; some
of these probably assist in the breakdown of rock
substrates like the one shown here.
29. The biggest organism is…
The largest living thing on earth (as of
the year 2000) is a 2400-year old
Armillaria ostoyae, commonly known
as a ―honey mushroom‖. This
specimen was found in Oregon
whereits underground mycelium
spreads from tree root covering 2,200
acres.
