Fungi Lab
Tentative
Phylogeny
Fig 28.8
Generalized fungal lifecycle
Key
Haploid (n)
Heterokaryotic
(unfused nuclei from
different parents)
Diploid (2n)
Heterokaryotic
stage
PLASMOGAMY
(fusion of cytoplasm)
KARYOGAMY
(fusion of nuclei)
Spore-producing
structures
Spores
ASEXUAL
REPRODUCTION
SEXUAL
REPRODUCTION
Zygote
Mycelium
MEIOSIS
GERMINATION
GERMINATION
Spores
Spore-producing
structures
Arbuscular
mycorrhizal
fungi
Sac
fungi
Club
fungi
Ascomycota
Basidiomycota
Zygomycota
Chytridiomycota
Zygote
Chytrids fungi
Glomeromycota
Phylogeny of fungi
Fungal Divisions
Chytridyomycota –
• Aquatic, with flagellated zoospores
• Diploid phase- sporophyte
Zygomycota = zygospores.
• Resistant zygote sporangium
Glomeromycota= zygospores
• arbuscular mycorrhizae.
Ascomycota = ascospores
• Endogenous meiospores
Basidiomycota = basidiospores
• Exogenous meiospores
Deuteromycetes – imperfect,
• no sexual reproduction
Chytridiomycota
• Chytrids use an absorptive mode of nutrition
and have chitin cell walls.
• There are a few unicellular chytrids, but most
form ceonocytic hyphae.
• Chytrids share key enzymes and metabolic
pathways with other fungal groups, but not
with the slime molds
• Ancestral to
other three
groups on land
• Forms flagellated
zoospores
Allomyces Life cycle
Diploid
#13
Haploid
#14
Allomyces gametophyte (n) slide
Gametophyte
Meiosporangia
Sporophyte
Allomyces (2n) Fresh Sample
Fungal Divisions
Chytridyomycota –
• Aquatic, with flagellated zoospores
• Diploid phase- sporophyte
Zygomycota = zygospores.
• Resistant zygote sporangium
Glomeromycota= zygospores
• arbuscular mycorrhizae.
Ascomycota = ascospores
• Endogenous meiospores
Basidiomycota = basidiospores
• Exogenous meiospores
Deuteromycetes – imperfect,
• no sexual reproduction
Zygomycete lifecycle
#15
#16
Zygosporangium formation
• +, - suspensor hyphae grow
together.
• Each tip cuts off a gametangia
with complete septa.
• Gametangia fuse into one large
heterokaryont.
• Nuclei pair up form many diploid
nuclei.
• Resistant wall forms on
Zygosporangium
• Before germination meiosis
takes place
• Forms sporangia, releasing
haploid spores
Asexual Spore
formation
• Haploid nuclei migrate to swollen
hyphal tip.
• Hyphal tip forms complete septum,
now a sporangium.
• Each nucleus forms a spore around
itself with cytoplasm, endospores.
• Sporangium wall breaks.
• Spores blow away.
Phycomyces
suspensors
Phycomyces on low power
Zygosporangia
Phycomyces
Gametangia fusing
Pilobolus
Sporangium with mitospores
Swollen sprangiophore
Spore dispersal
Positive Phototropism
Fungal Divisions
Chytridyomycota –
• Aquatic, with flagellated zoospores
• Diploid phase- sporophyte
Zygomycota = zygospores.
• Resistant zygote sporangium
Glomeromycota= zygospores
• arbuscular mycorrhizae.
Ascomycota = ascospores
• Endogenous meiospores
Basidiomycota = basidiospores
• Exogenous meiospores
Deuteromycetes – imperfect,
• no sexual reproduction
Ascomycota: Sac fungi produce sexual
spores in saclike asci
• Mycologists have described over 60,000
species of ascomycetes, or sac fungi.
• They range in size
and complexity
from unicellular
yeasts to
elaborate
cup fungi and
morels.
Ascomycetes are characterized by an extensive
heterokaryotic stage during the formation of ascocarps.
Fig. 31.10
Ascus formation
• Hyphal tip makes complete septum,
Nuclei fuse – a single 2n nucleus
• Meiosis – 4 haploid nuclei
• One mitotic division – 8 haploid nuclei
• Each nucleus cuts off some cytoplasm and
forms new wall, inside original hyphae wall.
• 8 ascospores are forcibly ejected by osmotic
pressure.
• Different forms of ascocarp have evolved.
Ascospore formation
Mitosis
Zygote
N+N
Meiosis
Spore wall
Peziza sp.
apothecia
Apothecia- #18
Asci – Slide #18
Morchella sp.
Morchella x-section
Morchella slide
Sordariaperithecia
Sordaria slide #
Fresh Sordaria slide
Saccharomyces cervisea
Budding
Conidia
• Many Ascomycetes reproduce asexually by
producing enormous numbers of Conidia,
asexual spores, (exogenous mitospores) which
are usually dispersed by the wind.
Conidiophore
continuously
divides forming
more spores at
tip.
Fungal Divisions
Chytridyomycota –
• Aquatic, with flagellated zoospores
• Diploid phase- sporophyte
Zygomycota = zygospores.
• Resistant zygote sporangium
Glomeromycota= zygospores
• arbuscular mycorrhizae.
Ascomycota = ascospores
• Endogenous meiospores
Basidiomycota = basidiospores
• Exogenous meiospores
Deuteromycetes – imperfect,
• no sexual reproduction
Basidiomycota
•
•
•
•
Typical Mushroom
Almost no asexual reproduction
Many mycorrhizae species
Oldest organism ?
Mushrooms caps have
basidia on gills.
The spores drop
beneath the cap and are
blown away.
• The life cycle of a Basidiomycete usually includes
a long-lived dikaryotic mycelium.
Fig. 31.12
Basidia formation
Coprinus
Basidiospores
Lichens
• Symbiosis of
– Phycobiont, algae / cyanobacteria
– Mycobiont - fungi.
• Not individual organisms
• Primary colonizers of new land in
succession, and in tundra areas
• Soredia asexually reproduce lichen
– Fungi often reproduce on their own.
• Lichen acids, dyes
Fig. 31.17
Three growth forms:
1. Crustose – flat on
stones
2. Foliose- leaf-like as
in picture
3. Fruticose- upright
growing
Phycobiont in inner
layers protected by
fungi on top and
bottom
(a) A fruticose (shrub-like) lichen
(b) A foliose (leaf-like) lichen
(c) Crustose (crust-like) lichens
Physcia
# 28
Ascocarp
Phycobiont
Umbilicaria sp.
Upper Cortex
Phycobiont layer
Filamentous Hyphal layer
medulla
Lower Cortex
Glomeromycota
• Has some characteristics similar to
zygomycetes.
• DNA comparisons show then to be their
own group
• Form Arbscular endomycorrhizae
Endotropic Mycorrhizae
Arbuscular mycorrhizae
2.5 m
Plant cell wall