Chapter 16
Lecture Outline
Kingdom Fungi
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Outline

Introduction

Distinctions Between Kingdoms Protista and Fungi

Kingdom Fungi
• Phylum Chytridiomycota – The Chytrids
• Phylum Zygomycota – The Coenocytic True Fungi
• Phylum Ascomycota – The Ascomycetes (Sac Fungi)
• Phylum Basidiomycota – The Basidiomycetes (Club Fungi)
• Phylum Deuteromycota – The Deuteromycetes (Imperfect
Fungi)

Lichens
Introduction

Fungi and bacteria are the most important
organisms that break down organic materials.
• For eg: Oyster mushroom (Pleurotus ostreatus)
can tolerate exposure to seawater and is capable
of degrading soil contaminated with diesel fuel.

Fungi produce intertwined mass of delicate
threads.
• Hyphae (singular: hypha) - Individual threads
• Mycelium - Mass of hyphae
Distinctions Between Kingdoms
Protista and Fungi

All true fungi are filamentous or unicellular
heterotrophs, most of which absorb their food in
solution through cell walls.

Chitin in cell walls

All are filamentous, with the exception of some chytrids
and all yeasts.

Most lack motile cells.

Members of Kingdom Fungi are placed in five phyla.

Recent DNA studies have placed the fungi more closely
with animals than plants.
Kingdom Fungi

Phylum Chytridiomycota - The chytrids
• Simple, mostly one-celled organisms
• Some are parasitic, and other are saprobic.
–
Saprobic - Feed on nonliving organic material
• Some consist of a spherical cell with colorless,
branching threads (rhizoids) at one end for
anchorage.
• Some develop short hyphae or even complete
mycelia that is coenocytic.
–
Coenocytic - Without crosswalls
Kingdom Fungi

Phylum Chytridiomycota - The chytrids
• Most primitive group of fungi (saprobic and aquatic).
• Many reproduce only asexually through the production of
zoospores within a spherical cell.
• Sexual reproduction by fusion of haploid gametes
• Zygote undergoes meiosis and is often a resting spore.
Kingdom Fungi

Phylum Zygomycota - The
coenocytic true fungi
• Black bread molds - Best-
known members of this phylum
–
Rhizopus - Well-known and found
everywhere
• Coenocytic hyphae with
numerous haploid nuclei
• Asexual reproduction:
–
–
Sporangiophores grow upright
and produce sporangia at tips.
Black spores formed in sporangia.
A zygomycete sporangium
Kingdom Fungi

Phylum Zygomycota - The coenocytic true fungi
Sexual reproduction by conjugation

–
Progametangia on hyphae of
different mating strains
become gametangia.
–
Gametangia merge and
become multinucleate
coenozygote when nuclei of
two strains fuse in pairs
–
Thick wall forms around
coenozygote =
zygosporangium containing
numerous diploid nuclei.
–
Meiosis forms spores in
sporangia on sporangiophores.
Kingdom Fungi

Phylum Zygomycota - The coenocytic true fungi
• Human and ecological relevance of the coenocytic
true fungi:
–
Food sources
o
–
Tempeh in Indonesia
Industrial uses
o
Pharmaceuticals
« Manufacture of birth control pills and anesthetics
o
Pigments
« Yellow pigment for coloring margarine
Kingdom Fungi

Phylum Ascomycota The ascomycetes (sac
fungi)
• Truffles are
reproductive bodies.
• Also includes yeasts,
powdery mildews,
ergot, and morels

Most produce mycelia
with hyphae partitioned
into individual
cylindrical cells.
Kingdom Fungi

Phylum Ascomycota - The ascomycetes (sac fungi)
• Asexual reproduction:
–
Single or chains of conidia produced at tips of hyphae
called conidiophores.
–
Budding - Yeasts
Budding in yeast
Kingdom Fungi

Phylum Ascomycota - The ascomycetes (sac fungi)
• Sexual reproduction:
–
Antheridium and ascogonium from two hyphae connect.
–
Male nuclei migrate into ascogonium where nuclei pair, but do
not unite.
–
Ascogenous hyphae, whose cells contain one male and one
female nucleus, grow from ascogonium.
–
Ascoma forms, with hymenial layer composed of sacs called
asci (singular: ascus).
–
The two nuclei in each ascus
unite to form zygotes that
undergo meiosis.
–
Resulting cells divide by mitosis
forming a row of eight
ascospores in each ascus.
Ascoma
Kingdom Fungi

Phylum Ascomycota - The ascomycetes (sac fungi)
Sexual
reproduction:
Kingdom Fungi

Phylum Ascomycota - The ascomycetes (sac fungi)
• Human and ecological relevance of the sac fungi:
–
Food:
o
Morels and truffles
o
Yeast
« Fermentation produces ethyl alcohol - Wines, beers
« CO2 causes bread dough to rise and gives it porous
texture.
Kingdom Fungi

Phylum Ascomycota - The
ascomycetes (sac fungi)
• Human and ecological
relevance:
–
Ergot fungus may infect rye
and other grains.
o
o
–
Ergotism may occur in those
who eat the contaminated
bread.
Ergot drugs are medicinally
useful in small doses.
« Initial source for the
manufacture of LSD
Plant diseases - Dutch elm
disease, chestnut blight
Kingdom Fungi

Phylum Basidiomycota - The basidiomycetes
(club fungi)
• Includes mushrooms,
toadstools, puffballs,
shelf fungi, rusts,
smuts, jelly fungi
• Hyphae divided into
individual cells.
Kingdom Fungi

Phylum Basidiomycota - The basidiomycetes
(club fungi)
• Asexual reproduction:
–
Infrequent
o
Mainly through conidia
• Each cell of hyphae contain a single haploid
nucleus = monokaryotic hyphae.
• Sexual reproduction:
–
Hyphae of individual mating types unite and initiate a new
mycelium, called dikaryotic hyphae, in which each cell
has one nucleus from each original mating type.
Kingdom Fungi

Phylum Basidiomycota - The basidiomycetes
(club fungi)
• Sexual reproduction:
–
Dikaryotic mycelium forms basidioma (plural:
basidiomata) = mushroom.
o Mushroom
composed of
cap = pileus,
stalk = stipe,
and annulus.
o Gills - Plates
that radiate out
from stalk on
underside of
cap
Kingdom Fungi

Phylum Basidiomycota - The basidiomycetes
(club fungi)
• Sexual reproduction:
–
Basidia (swollen ends
of hyphae) on gills
–
The two nuclei in each
basidium unite and the
resulting diploid nucleus
undergoes meiosis.
–
4 resulting
basidiospores sit on
sterigmata at tip of
basidium.
Kingdom Fungi

Phylum Basidiomycota - The basidiomycetes
(club fungi)
Sexual
reproduction:
Kingdom Fungi

Phylum Basidiomycota
• Fairy rings - Dikaryotic
hyphae radiate out from
starting point, producing
basidiomata.
• Boletes - Produce
spores on surface of
pores instead of gills
Kingdom Fungi

Phylum Basidiomycota
• Shelf fungi - Grow
horizontally from bark
or dead wood
• Puffballs - Spores released
from pore at top.
• Bird’s nest fungi - Egglike
bodies contain basidiospores.
Kingdom Fungi

Phylum Basidiomycota
• Parasitic species that do
not form basidiomata:
–
–
Smuts
o
Grain crops
o
Mycelium absorbs
nutrients from host cells.
o
Secrete substances that
stimulate host cells to
form tumors
Rusts - Attack a wide
variety of plants
o
Black stem rust Requires two hosts
Corn smut
Kingdom Fungi

Phylum Basidiomycota
• Lifecycle of rusts:
Kingdom Fungi

Phylum Basidiomycota
• Human and ecological relevance of the club fungi:
–
Poisonous
o
–
Fewer than 75 of the approximately 25,000 described
species are poisonous.
Food
o
o
Shiitake mushrooms
« High in protein,
calcium, phosphorous,
and iron.
Portabella mushrooms
–
Lentinacin and other
pharmaceutical extracts
–
Nutrient recycling in soil
Commercial mushroom bed
Kingdom Fungi

Phylum Deuteromycota - The deuteromycetes
(imperfect fungi)
• Fungi for which a
sexual stage has not
been observed
–
Grouped together in
an artificial phylum
–
Most commonly
reproduce by conidia
Conidiophore of Aspergillus
Kingdom Fungi

Phylum Deuteromycota - The deuteromycetes
(imperfect fungi)
• Human and ecological relevance of the imperfect fungi:
–
–
Penicillium
o
Antibiotics
o
Gourmet cheese
Aspergillus
o
Citric acid, soy sauce,
miso, artificial flavoring
o
Photographic developers,
dyes
o
Aspergilloses (respiratory
disease), athlete’s foot
o
Aflotoxin (carcinogen)
Penicillium
colony
Blue
cheese
Lichens

Consist of a fungus and an alga (or blue
green bacterium) intimately associated in a
spongy thallus
• Photosynthetic component supplies food.
• Fungus protects the photosynthetic organism
from harmful light intensities, and absorbs and
retains water and minerals.
–
Three genera of green algae and one genus of
cyanobacterium involved in 90% of all lichen species.
–
Each lichen has own unique species of fungus, usually
a sac fungus.
–
Lichen species are identified according to their fungus.
Lichens

Grow very slowly, and are capable of living
extremely long periods of time.
• Gelatinous substance in thallus allows them to
withstand alternating wet and dry periods.

Usually consist of three or four layers:
• Upper cortex - Protective layer
–
Compressed hyphae with gelatinous substances
• Algal layer - Algae cells scattered among hyphae
• Medulla - Loosely packed hyphae
• Lower cortex - May or may not be present
–
Covered with hyphae called rhizines for anchorage
Lichens
Lichens

Usually grouped into three major growth forms:
• Crustose - Attached
to or embedded in
substrate over entire
lower surface
• Foliose - Contain
leaf-like thalli which
often overlap
• Fruticose - Resemble
miniature upright
shrubs, or hang
down in festoons
from branches.
Lichens

Human and ecological relevance of lichens:
• Exceptionally sensitive to pollution
–
Sulfur dioxide
o
–
Possible to calculate amount of sulfur dioxide
present in air solely by mapping occurrence or
disappearance of certain lichens.
Nuclear radiation
• Degradation of historic structures
• Food for animals - Reindeer eat fruticose lichen.
• Food supplements
• Antibiotic properties
• Dyes
Review

Introduction

Distinctions Between Kingdoms Protista and Fungi

Kingdom Fungi – The True Fungi
• Phylum Chytridiomycota – The Chytrids
• Phylum Zygomycota – The Coenocytic True Fungi
• Phylum Ascomycota – The Ascomycetes (Sac Fungi)
• Phylum Basidiomycota – The Basidiomycetes (Club Fungi)
• Phylum Deuteromycota – The Deuteromycetes (Imperfect
Fungi)

Lichens