FUNGI

Mycology -

the study of fungifungi - singularfungus - plural

1) fungi are eukaryotic•they have a nuclei & mitochondria

2) they are heterotrophs

•they depend on other organisms for food3) they are multicellular

4) they cannot move on their own

4 Main Characteristics of Fungi

1) fungi lack chlorophyll

2) fungi are not photosynthetic•cannot produce their own food

3) they never reproduce by seeds4) most fungi have cell walls made of “chitin”… Except molds

4 Reasons Fungi Are Different From Plants

cellulose•Plant cell walls are made of what?

•molds have cell walls made of cellulose…like plants

•most are saprophytes•some are parasites

Saprophyte-feeds on dead/decaying organisms

• Smallest = Yeast cells• Largest = 3.5mile wide HUMUNGOUS

FUNGUS!!!!!– The famous “honey mushroom” (Armillaria

ostoyae) covering some 2,200 acres in Oregon’s Malheur National Forest

• If it’s so big, why can’t we see it?

• Almost all of it is underground…

Fungi Are Decomposers…

Hyphae - network of thin thread-like structures that form the “body” of a fungus

• Hyphae branch out until they cover & digest their food

• Hyphae may either be “sepate” (with cell walls) or “aseptate” (no cell walls, with many nuclei!)

• Hyphae contain cytoplasm & 1 or more nuclei

hypha - singularhyphae - plural

Parts of a Fungus

Septate and Non-septate Hyphae

Mycelium - a mass of hyphaemycelia - plural

•The mycelium is usually hidden in the soil, in wood, or another food source

•A mycelium may fill a single ant, or cover many acres

Parts of a Fungus

Mushrooms are for sexual reproduction (~flowers)

Mycelium = body of the fungus

Hyphae = the “bricks” from which the mushroom is built

single hypha

Mass of hyphae (mycelium)

Germ tube (Growing Spore)

(initial hypha)

Fungi usually reproduce via

“spores”

FUNGI• FRUITING BODY

– The visible part– Contains spore-producing structures– Larger ones we call “mushrooms” or “toadstools”

Fungal Mycelia

Examples of Fungal Mycelia

FUNGI

• FEEDING TYPES (NUTRITION)– Saprophytic – feed on

dead matter– Parasitic – feed on

living organisms

FUNGI

• HABITATS– Need organic material, moisture– Live almost everywhere, from polar icecaps to

deserts to oceans– Reach new areas through spores carried by

wind– Spores are necessary to find new food

sources

FUNGI

• FOUR GROUPS OF FUNGI -- 81,500 species of fungi divided by structure and reproduction– ZYGOMYCETES – bread molds– ASCOMYCETES – sac fungi (morels, truffles,

and yeasts– BASIDIOMYCETES – mushrooms, puff balls– DEUTEROMYCETES – imperfect fungi

(penicillium)

Phylogeny of Fungi

FUNGI

• Common molds – Zygomycetes– Frequently found in soil or on dead animals or plants– Reproduce asexually AND sexually

• Sexually if an opposite mating type makes contact…

– Hyphae lack septa– Specialized hyphae

• Rhizoids that absorb nutrients and hold molds to their food source

• Stolons that connect groups of rhizoids together• Sporangia produces spores during reproduction

FUNGI

• ZYGOMYCOTA gets its name from the tough spores produced during sexual reproduction

Asexual Reproduction in Rhizopus stolonifer

nuclear fusion meiosis

zygospore (2n)

spores (n) Zygospore Spore sac

mycelium develops from germinated spore

rhizoids

stolon

ASEXUAL REPRODUCTION

(mitosis)

contact between hyphae of two mating strains

germinating zygospore

Diploid Stage

Haploid Stage

young zygospore

gametangia fusing

50 µm

spores (n)

FUNGI

• Sac fungi – Ascomycetes• Powdery mildews, yeasts, fungi in lichens, and

morels • Characteristic that links these are production of

saclike structures called asci during sexual reproduction

• Asexuall reproduction is rare

Reproduction in Ascomycetes

Ascomycetes: Scarlet Cup, Truffles and Morel

Carbon Balls Fungus

FUNGI

• Club Fungi – Basidiomycetes• “Mushrooms” are club fungi• Reproduce sexually (asexual reproduction is rare)• Three visible structures of mushrooms

– Stipe– Cap– Gills made from tightly packed mycelia

• Fruiting bodies are called basidia

Structure of a Mushroom

Remember: most of a mushroom is the underground mycelium…

Structure of a Mushroom

ANNULUS

STIPE

Gills

Basidiomycetes (club fungi): Greville's bolete (top left), turkey tail (bottom

left), stinkhorn (right)

Shaggy Mane

Witch’s Butter

Stinkhorn

Amanita

A Fairy Ring…

• Why is it a circle?

• Soil nutrients in the center have been depleted!

FUNGI

• Imperfect fungi – Deuteromycetes• Reproduce asexually and NOT sexually• Examples are athlete’s foot & ringworm• Example that is helpful is Penicillium because it

make the antibiotic• Spores called conidia come from hyphae called

conidiophores

IMPERFECT FUNGI

IMPERFECT FUNGI

Aspergillus

A Moldy Orange & Penicillium

Budding Yeast

FUNGI

• ECOLOGICAL ROLES– Decompose dead organisms; clear out dead

plants and animals– Recycle nutrients

FUNGI

• ECOLOGICAL ROLES– Symbiotic Relationships

A) LICHEN --a symbiotic association between a fungus and a photosynthetic partner, usually a cyanobacterium or green alga.The fungal hyphae provide protection and hold moisture while food is provided by the photosynthetic partner.

Lichens

Anatomy of a Lichen

FUNGI

• ECOLOGICAL ROLES Cont.

B) Mycorrhizae: a symbiotic association between a fungus and plant roots.– Over 90% of plants have fungi associated with their

roots. The fungus absorbs and concentrates phosphates for delivery to the plant roots. In return, the fungus receives sugars synthesized by the plant during photosynthesis.

Mycorrhizae

Test of Benefits of Mycorrhizae

FUNGI

• ECOLOGICAL ROLES–Some parasitic fungi are actually

human pathogens causing athlete's foot and ringworm

–Some parasitic fungi are plant pathogens that destroy crops

–Produce medicine (antibiotics)

Common Mold, Rhizopus, Decomposing Strawberries

Fungal Diseases of Plants

FUNGI

• ECONOMIC ROLES– Used directly as food, or to make food

• Yeasts are useful in the making of bread and fermented drinks.

Fungal Production of Antibiotic