Unit 6--Microbiology

Chapter 21

Fungi

Fungal Characteristics

• Filamentous bodies:

• Hyphae = thin filaments

• Mycelium = entire mass of hyphae

• Chitinous cell walls (instead of cellulose)

Fungal “invasion” in leaf

Fungal characteristics

• How they obtain food:

• 1) Secrete digestive enzymes into environment

• 2) Digestion takes place outside their body

• 3) They absorb what they need, leaving the rest

• Why is this an advantage ?

(to the rest of the world)(Compost)

Fungal characteristics

• Reproduction:

• 1) Asexually (usually used when times are good with plenty of food available)– Haploid spores produced in large numbers

• 2) Sexually (usually used when times are harsh)– Haploid gametes fuse to form a zygote that

can survive hard times

Phylum…examples…types of reproduction

• Zygomycota (Zygote-producing fungus)

• Rhizopus (black bread

mold)• Asexual with

sporangia• Sexual with

zygospores

Phylum…examples…types of reproduction

• Zygomycota (Zygote-producing fungus)

• Rhizopus (black bread

mold)• Asexual with

sporangia• Sexual with

zygospores

Sporangia can produce 50,000 spores

Formed when 2 gametes unite to form a zygote that in enveloped by a zygosporewhich survives harsh times

Rhizopus sporangia @ 2,990 x

Phylum…examples…types of reproduction

• Ascomycota(cup fungus)

• Ex: yeast, truffles, & many other molds

• Asexual with conidia

• Sexual with ascus (sac-like spore case) inside a cup

($900 per pound!)

Aspergillus conidia

Asci (with 8 spores)making up the “cup”

Phylum…examples…types of reproduction

• Basidiomycota…club fungus

• Ex: mushrooms, toadstools, puffballs, & bracket fungus

• Asexual is rare• Sexual is club-shaped

spore case called basidium

4X 10X

40X

Phylum…examples…types of reproduction

• Deuteromycota…imperfect fungus• Ex: ringworm, athlete’s foot, penicillium

mold• Asexual only• No known sexual stage

Other relatives

• Lichens:

• Symbiotic fungus & algae

• Fungus provides “home,” algae provides “food”

• Mycorrhizae:Mycorrhizae:

• Symbiotic fungus & Symbiotic fungus & plant root cellsplant root cells

• Root cells provide Root cells provide “home” “home”

• fungus provides fungus provides mineral transportmineral transport