2. Sub-Topic
Brief Criteria of the Fungi Kingdom
Differences between the Old and
Modern Classification
Difficulties of Classifying Fungi
Introduction, Basic Characteristics and
Life Cycles
4. Definitions
Mycologists : scientists who study
fungi.
Mycology : scientific discipline
dealing with fungi.
Mycoses : diseases caused in
animals by fungi.
5. Fungus versus Fungi
“Fungus” is used inclusively for a
heterogenous group of organisms
that have traditionally been studied
by mycologists .
“Fungi” refers to the organisms in the
Kingdom Fungi, the true fungi, also
called the “Eumycota”.
6. How many species of fungi exist?
- 90,000 species of fungi
described
- 1,700 new species
described each year
7.
8. What is a fungus?
A eukaryotic organisms. Fungi are neither
a plants, nor animals
A heterotrophic organism devoid of
chlorophyll that obtains its nutrients by
absorption.
Heterotrophic by absorption.
Reproduced by spores.
The primary carbohydrate storage
product of fungi is glycogen.
9. Most fungi have a thallus composed of
hyphae (sing. hypha) that elongate by tip
growth.
The fungal thallus consists of hyphae; a
mass of hyphae is a mycelium.
10. The Characteristics of Fungi
Structure – hyphae, mycelium, thalus
Heterotrophic by Adsorption
Reproduced by Spores
11. Kingdom Fungi
Nutritional Type Heterotroph
Multicellularity All, except yeasts
Unicellular, filamentous,
Cellular Arrangement
fleshy
Food Acquisition Method Absorptive
Characteristic Features Sexual and asexual spores
Embryo Formation None
13. 1) The Structure - Hyphae
Hyphae = tubular units of
construction
Tubular
Hard wall of chitin
Cross walls may form
compartments (± cells)
Multinucleate
Grow at tips
15. Hyphal growth
Hyphae grow from their tips
Mycelium = extensive, feeding web of
hyphae
Mycelia are the ecologically active bodies of
fungi
This wall is rigid Only the tip wall is plastic and stretches
17. 2. Heterotrophic by Absorption
Fungi get carbon from organic sources
Hyphal tips release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Nucleus hangs back
and “directs”
Product diffuses back
into hypha and is used
18. 3. Reproduced by
spores
Spores are reproductive cells
Sexual
Asexual
Formed: Pilobolus sporangia
Directly on hyphae
Inside sporangia
Fruiting bodies
Amanita fruiting body Penicillium hyphae
20. Old Classification
Carl Linnaeus (1707-1778) the
“Father of Taxonomy”
“ Minerals exist; plants
exist and live; animals
exist, live and sense.”
Plants without obvious
sexual organs were
classified in Class
Cryptogamia (lichens,
fungi, mosses, ferns)
Fungi are primitive plants
under this classification of
organisms.
21. Old Classification
The Five kingdom system (Whittaker, 1969)
Eukarya (includes all organism with a
nucleus & membrane bound
organelles).
Plants and Animals are fairly obvious
Fungi, are very distinct from the other
kingdoms.
Kingdom Protista is a “dumping
ground” for organisms that don’t fit into
the other eukaryotic kingdoms.
24. Modern Classification
At least 7 kingdoms are now recognized
(Patterson & Sogin 1992) :
Eubacteria,
Archaebacteria,
Animalia,
Plantae,
Eumycota,
Stramenopila (Chromista),
Protoctista (Protozoa, Protista)
25. Based on molecular evidence: base sequences
from ribosomal RNA (Patterson & Sogin 1992)
26. Systems of classifying fungi
1) 1860
HOGG proposed the term PROTOCTISTA - fungi and neither
Plant or Animal.
This kingdom composed mostly of unicellular organisms.
The kingdom was later replaced by 2 kingdoms – MYCOTA &
MONERA (prokaryotes) and PROTOCTISTA(eukaryotes).
2) 1947
Microscopes enable study of complex structural
characteristics.
New classification (WOLF & WOLF, 1947)
3) 1969
Fungi in its own kingdom by WHITTAKER – FUNGI KINGDOM.
27. Systems of classifying fungi
4) 1998
Modification by MARGUILIS & SCHWARTZ – used characteristics
(structure & function).
• MONERA: Prokaryotes – bacteria, actinomycetes, blue-green
algae.
• PROTOCTISTA: Eukaryotes – protozoa and other unicellular and
colonial organisms such as water moulds, slime moulds and
slime nets.
• FUNGI : Eukaryotes – organisms that lack flagella that develop
from spores such as yeast, molds, rusts and mushrooms.
• PLANTAE: Eukaryotes – organisms that develop from embryos
such as liverworts, mosses and vascular plants.
• ANIMALIA: Eukaryotes – organisms that develop from a
blastula (hollow ball of cells) such a sponges, worms,
arthropods and mammals.
28. Marguilis and Schwartz (1998)
Classify the fungi into 3 phyla : Zygomycota,
Ascomycota and Basidiomycota.
Chytrids (CHYTRIDIOMYCOTA) in the
Kingdom Proctista.
Deuteromycota with their closest relatives
that are the Ascomycota and
Basidiomycota.
Lichen with the Phylum Ascomycota.
29. Other classifications
MOORE, 1998 (quoted from Pfieffer, M., et al.,
2001) states that plants, animals and fungi
can be separated based on how they
obtain energy.
Plants possess chloroplasts as photosynthetic
structures used to produce food.
Animals possess mitochondria used for
internalized digestion.
Fungi excrete enzymes into the food source
they live within external digestion.
30. Classification using molecular
research techniques
BALDAUF & PALMER (1993), WAINWRIGHT et
al. (1993) and HASEGAWA et al (1993)
The above current schemes agree that the
three major kingdoms are separated
→ thereby confirmed that there are no
connection between the fungi-plant
kingdom.
31. Question
Fill in the blanks of the systematic of classification
1) Kingdom
2) Division / Phylum
3) ___________
4) Order
5) ___________
6) Tribe
7) ___________
8) Species
Sometimes there are subdivisions and subclasses
32. Question
Fill in the blanks of the systematic of classification
1) Kingdom
2) Division / Phylum
3) Class
4) Order
5) Family
6) Tribe
7) Genus
8) Species
Sometimes there are subdivisions and subclasses
33. Hierarchical Classification
Kingdom Fungi
Phylum Basidiomycota
Class Basidiomycetes
Order Agaricales
Family Agaricaceae
Genus Agaricus
Species:
Agaricus campestris L.
34. How are fungi named?
To determine the correct name for a
taxon, certain steps must be
followed, including:
Effective publication
Valid publication
• Description or diagnosis in Latin
• Clear indication of rank
• Designated type
35. Nomenclature
Nomenclature: the “allocation of
scientific names to the units a systematist
considers to merit formal recognition.”
(Hawksworth et al., 1995. The Dictionary of
the Fungi).
The nomenclature of fungi is governed by
the International Code for Botanical
Nomenclature, as adopted by the
International Botanical Congress.
36. Reasons why it is not easy to
classify fungi
Fungi comprise of a broad number of organisms.
Fungi have various forms depending on the
environment and conditions in which they grow.
Many terms being used to describe the
morphological structures of fungi.
38. Ascomycota – “sac fungi”
Teleomorphic fungi
Produce sexual and
asexual spores
Sex. – asci
Asex. – common
Cup fungi, morels, truffles
Important plant parasites &
saprobes
Yeast - Saccharomyces
Septate
Most lichens
A cluster of asci with spores inside
39. Basidiomycota – “club fungi”
Produce basidiospores and
sometimes conidiospores
Sex – basidia
Asex – not so common
Long-lived dikaryotic mycelia
Rusts & smuts – primitive plant
parasites
Septate
Mushrooms, polypores, puffballs
Enzymes decompose wood
Mycorrhizas
SEM of basidia and spores
40. Zygomycota – “zygote fungi”
Conjugation fungi
Coenocytic
Sex - zygosporangia
Asex - common
Produce sporangiospores
and zygospores
Hyphae have no cross walls
Grow rapidly
Rhizopus, Mucor
(opportunistic, systemic
Fig 31.6 Rhizopus on
mycoses)
strawberries
Mycorrhizas
41. True Fungi versus Slime Moulds
True fungi:
- those that are hyphal
- possess cell walls throughout most of their life cycle
- are exclusively absorptive in their nutrition.
Slime moulds:
- those that do not form hyphae
- lack cell walls during the phase that they obtain
nutrients and grow
- are capable of ingesting nutrients by phagocytosis. So
they are more common to Protista although they
produce fruiting bodies like fungi.
- The most studied of them are the cellular slime moulds
and the plasmodial slime moulds or Myxomycetes.
42. QUESTION
The fungus can never be classified in
Plantae or Animalia?
EXPLAIN WHY?
(Hint ! LOOK AT ITS MOBILITY,
REPRODUCTION & NUTRITION)
Notes de l'éditeur
Fungal mycelia can be huge, but they usually escape notice because they are subterranean. One giant individual of Armillaria ostoyae in Oregon is 3.4 miles in diameter and covers 2,200 acres of forest, It is at least 2,400 years old, and weighs hundreds of tons. (Actually noone has seen this of this extent – but cultures have been taken from soil over that area and all isolates have been found to be the same individual) Ten cubic centimeters of rich organic soil may have fungal hyphae with a surface area of over 300 cm 2
Most enzyme release (and absorption) at tips Proteins and other materials synthesized by the entire mycelium are channeled by cytoplasmic streaming to the tips of the extending hyphae.
Fungi reproduce by releasing spores that are produced either sexually or asexually. The output of spores from one reproductive structure is enormous, with the number reaching into the trillions. Dispersed widely by wind or water, spores germinate to produce mycelia if they land in a moist place where there is food.
Mycologists have described over 60,000 species of ascomycetes, or sac fungi . Ascomycota tend to grow from spore to spore in one year and relate well to living plant tissues There is diverse form in the growth and fruiting structures – yeasts to morels, many intermediate (and small) Asexual reproduction by conidia (externally produced, not in sporangia) Half of the Ascomycota form lichens (evolved 8 or more times in different orders) but not all lichens are Ascomycotes
Most of the 600 zygomycote, or zygote fungi , are terrestrial, living in soil or on decaying plant and animal material. Asexual reproduction in sporangia One zygomycote group form mycorrhizas , mutualistic associations with the roots of plants.