Transcript Photosynthesizers

Introduction to the Fungi
Basic phylogeny
How many fungi do you see??
There is only one fungus. In this picture. Most of it is underground. Each of the
mushrooms you see is a “fruiting body” (like a flower) that the mushroom uses to
reproduce.
Example of a “humungous
fungus”
• Armillaria bulbosa – a
mushroom producing wood
decomposer
• Covers at least 38 acres in a
forest in Michigan
• Estimated to weigh 100
tons (size of a blue whale)
• Estimated to be at least
1500 yrs old
Kingdom Fungi
• Eukaryotic heterotrophs with
external digestion
– Most are saprotrophs:
digest decaying material
– Important for recycling
nutrients
• Range from a single cell
(yeast) to mushrooms whose
mycelia cover hundreds of
acres
• Chitinous cell walls
• Are classified by the way the
make spores (sac, club, etc)
• “imperfect” lack sexual
reproduction
Structure of Fungi:
Most fungi are filamentous because the main
body is composed of thread-like filaments called
hyphae which form the mycelium.
Fungi which produce
“mushrooms” are called
club fungi.
Hyphae = the “bricks” from which the mushroom is built
Fungi Importance
• Food production: improved yield due to symbiosis
(plants and fungi mycorrhizae), leavened bread
(yeast)
• Recycling nutrients (through decomposition)
• Industrial enzymes (bioremediation)
• Plant growth hormones
• Antibiotics (penicillin)
• Lichens = symbiosis between fungi and algae
– Good indicators of air quality
Penicillium: produced by a fungus
WWI, bacterial
infections killed
more soldiers than
bullets.
1928 Dr. Andrew Fleming
working at St. Mary’s
Hospital in London noticed
that mold growing on
staph bacterial culture
plates had killed the
pathogen
zone of dead
bacteria
Penicillin kills bacteria by interfering with
the ability to synthesize cell wall.
Mycorrhizae: fungi/plant symbiosis
• “myco” = fungus and “rhiza” = root
• Symbiotic association between plant
roots and fungi
• Advantages to plant:
•
Fungi are better than plants at
acquiring mineral nutrition (P,K, N)
from the soil.
•
Fungi improve a plant’s access to water
because fungi
– can access greater soil volume
– can break molecules down into
useable forms
– Haustoria =
specialized hyphae
for absorption
Mycorrhizae: Fungi can access more of
the soil because hyphae of the fungus are
smaller than plant roots
Root Hair
Hyphae are
1/500th the
diameter of a
plant root
hair
hyphae
Fungi expand the surface area
available for nutrient uptake
Lichens:
fungi/algae symbiosis
Fungus = mycobiont
Algae = photobiont
Controlled parasitism??
Lichen are among the “pioneer species”
which create soil in areas that have only
rocks (such as a lava field).
Can withstand areas of drought and
extreme temperature; slow growth.
They absorb nutrients from the air and
from rainfall so lichen are good
indicators of air quality.
Absorptive nutrition makes lichens
good indicators of air quality
Some fungi are predators.
• They catch and digest
other organisms (like
nematodes)
But still absorptive nutrition! Just have to catch it first…
Negative impacts of fungi
• In animals, infections such as athletes foot, ringworm.
• In plants, masses of spores cause discolouration of
the leaves so infections often called smuts, rusts,
spots and other names describing the symptoms.
Beetles were vector for Dutch Elm disease.
Tarspot of sycamore
Eyespot of wheat
Leaf rust of daisy