Fungal kingdom and systematic

1. Chapter 3
Fungal Kingdom and Systematic
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2.  Taxonomy [Greek taxis, arrangement or order, and nomos, law, or nemein, to
distribute or govern] is defined as the science of biological classification.
 In a broader sense it consists of three separate but interrelated parts: classification,
nomenclature, and identification.
 Classification is the arrangement of organisms into groups or taxa (s., taxon)
based on mutual similarity or evolutionary relatedness.
 Nomenclature is the branch of taxonomy concerned with the assignment of
names to taxonomic groups in agreement with published rules.
 Identification is the practical side of taxonomy, the process of determining that
a particular isolate belongs to a recognized taxon.
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3. 3

4. In taxonomy the most commonly used levels or ranks (in ascending order) are species, genera, families,
orders, classes, and phyla
 Species—a group of related isolates or strains. Note that members of a species are not all identical;
individual strains may vary in minor properties. The difficulty for the taxonomist is to decide how
different two isolates must be in order to be classified as separate species rather than strains of the same
species.
 Genus—a collection of related species.
 Family—a collection of similar genera.
 Order—a collection of similar families..
 Class—a collection of similar orders.
 Phylum or Division—a collection of similar classes.
 Kingdom—a collection of similar phyla or divisions. The number of different kingdoms varies according
to the classification system used. 4

5. 3.1. Fungal Phylogeny
(Eumycota)=True Fungi
Classification is based on phylogenetics, types of spore production and type of nutrition
 Five phyla plus "imperfect fungi"
 Phyla separated mainly by how meiospores are formed (how sexual reproduction done)
1. Phylum Chytridiomycota – (include orders like Chytridiales, Spizellomycetales, Neocallimastigales,
Blastocladiales and Monoblepharidales)
2. Phylum Zygomycota – Also known as Common molds. Include classes like Zygomycetes, Zoopagales,
Entomophthorales, Glomales and Trichomycetes)
3. Phylum Glomeromycota – Glomeromycetes
4. Phylum Ascomycota –Also known as Sac Fungi; (Include classes like Loculoascomycetes, Pyrenomycetes,
Helotiales, Lecanoralean, Plectomycetes, Pezizales, Hemiascomycetes and Archiascomycets)
5. Phylum Basidiomycota – Also known as Club Fungi; (Include classes like Homobasidiomycetes,
Heterobasidiomycetes, Uridiniomycetes, and Ustilaginomycetes)
6. Imperfect Fungi (also known as Deuteromycetes) 5

6. 1. Phylum Chytridiomycota- chytrids (simplest of true fungi).
• Terrestrial and aquatic fungi that reproduce asexually by forming motile zoospores.
• Microscopic in size; may consist of single cells, a small multinucleate mass, or a true mycelium.
• Reproduce asexually or sexually.
• Some saprophytic; others are parasites of algae, other true fungi, and plants.
• Chytrids may provide clues about fungal origins.
• Phylogenetic systematics suggests that fungi evolved from a unicellular, flagellated protist.
• Ubiquitous in lakes, ponds, and soil.
• While there are a few unicellular chytrids, most form coenocytic hyphae.
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7. •The phylum Chytridiomycota comprises over 900 species in five orders
•apparently paraphyletic
•motile zoospores – only fungi with flagella (thus only fungi with true motility)
•primarily aquatic (rest of fungi are primarily terrestrial)
•likely either a sister group to other fungi or a paraphyletic basal assemblage
■fossils resembling modern chytrids date back as far as about 400 million years ago
• chytrids may give us a good picture of what the ancestors of all fungi were like
•reproduction
both sexual and asexual
some have alternation of generations
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8. Fig 3.1.. Chytrids on a dead leaf submerged in water. 8

9. B. Phylum Zygomycota – Zygomycetes
•apparently paraphyletic
•hyphae lack septa, except in reproductive structures
•hyphae typically multinucleate
•no dikaryotic hyphae (no hyphae contain two different and distinct nucleus)
•have homokaryotic hyphae: plasmogamy and karyogamy together, followed by zygosporangium formation, then
followed by meiosis when conditions are right
•sexual reproduction: meiospores made in zygosporangia
specialized, thick-coated microscopic structures that protect the diploid (zygotic) cells inside
contain one or more zygotic cells
considered “resting structures” because they are essentially dormant until an environmental signal of some
sort sparks the zygotic cells to undergo meiosis, forming meiospores and breaking open the zygosporangium
•asexual reproduction
more commonly seen than sexual reproduction for this group
mitospore-forming sporangia on sporangiophore stalks
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10. Fig 1.4. Life cycle of Rhizopus,a zygomycete.
This phylum is named for its characteristic zygosporangia.
•~1000 species of Zygomycota are known
•importance: Familiar molds that grow on meat, cheese and bread 10

11. C. Phylum Glomeromycota – Glomeromycetes
 monophyletic
 newly defined, previously thought to be Zygomycetes
 no evidence of sexual reproduction
 they reproduce asexually
 ~160 known species of Glomeromycota distributed among ten genera
 important for mycorrhizal relationships with many plants
 mycorrhizae: association of fungus with plant root (endomycorrhizae and exomycorrhizae)
■ a type of mutualism (relationship between 2 species where both benefit)
■ fungus extends into soil and aids in uptake of nutrients (P, Zn, Cu in particular) for plant
■ fungus obtains sugars from plant
■ very common, found with most plant roots – ~90% of plants have a mycorrhizal relationship with
Glomeromycetes
■ important in revegetation/reclamation of disturbed areas: if fungi not present, plants don’t do well!
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12. ■ two types of mycorrhizae:
endomycorrhizae: (the kind that Glomeromycetes make; sometimes called arbuscular
mycorrhizae)
 fungus penetrates into root cells
 most common type of mycorrhizal relationship
 only formed by Glomeromycetes, but over 200,000 plant species involved
 very general and probably have a long evolutionary history
ectomycorrhizae:
 fungus surrounds but does not penetrate root cells
 far fewer plants involved, usually a very specific relationship of one kind of fungus with
one kind of plant
 plants involved are often trees
 fungi involved are mostly Basidiomycetes, but some are Ascomycetes
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13. D. Phylum Ascomycota – Ascomycetes; sac fungi
 monophyletic
 septate hyphae
 both dikaryotic hyphae and monokaryotic hyphae (in fact, some are polykaryotic)
 sexual reproduction:
 ascus – sac where meiospores are formed (plural: asci)
 asci are contained in fruiting body called an ascoma (plural ascomata) or ascocarp
 ascoma is made of dikaryotic hyphae and monokaryotic hyphae
 asexual reproduction
 very common in Ascomycetes
 conidiophores: modified hyphae for making mitospores
 conidia: mitospores made by cells pinching off from cells at tips of conidiophores
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14. Fig 3.3. Life cycle of an Ascomycetes
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15.  ~45,000 species of Ascomycota are known
 importance: includes morels, truffles, yeasts, fungal part of lichens, and many animal and plant pathogens
■ some ascomata are edible and highly prized by gourmets
 truffles (worth up to >$620/Kg)
 morels edible fungi
■ yeasts – unicellular, ferment carbohydrates (actually yeasts in each fungal phylum, but most yeast are
Ascomycetes)
fermentation by yeasts useful for making alcoholic beverages and in baking; worth billions of dollars a
year to industry
released CO2 raises bread, carbonates beer and wine
released ethanol is the alcohol for beer and wine
Saccharomyces cerevisiae is an important lab organism
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16.  Lichens – mutualistic partnership between fungi and unicellular photosynthesizer (green alga or
cyanobacteria)
 fungus forms body and protects and directs photosynthesizer, obtains materials from partner
together, can colonize harsh environments (pioneer organisms – typically first organisms in an
environment)
 primary producers in harsh environments (base of food chains)
 example, reindeer in arctic eat large amounts of lichens
 some are pollution sensitive: used as bioindicators of air quality
 about 40% of Ascomycetes species are part of lichens
 pathogenic Ascomycetes: examples
human yeast infections
Dutch elm disease
chestnut blight
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17. E. Phylum Basidiomycota – Basidiomycetes; Club Fungi
•monophyletic, and in a clade with Ascomycota
•septate hyphae
•both monokaryotic and dikaryotic hyphae; dikaryotic hyphae predominate in life of organism
•sexual reproduction:
A.main form of reproduction for Basidiomycetes is sexual reproduction
B. basidium – club-shaped reproductive structure that produces meiospores (plural: basidia)
A.basidia (basidiospore) are contained in fruiting body called a basidioma (plural basidiomata) or
basidiocarp
B.basidioma is made of only dikaryotic hyphae
•asexual reproduction: usually do not make mitospores, but mycelium can become fragmented to form separate
individuals
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18. Fig 3.4. Life cycle of Basidiomycetes.
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19. •~22,000 species of Basidiomycota are known
•importance: include mushrooms, puffballs, shelf fungi, etc., as well as many rusts and
smuts
some basidioma are edible, some deadly poisonous, some hallucinogenic
sometimes form circle as fungus grows from initial point: “fairy ring”
pathogens of plants (smuts and rusts cause billions of dollars in damage to
grain crops).
important decomposers (as are most fungi)
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20. F. Imperfect Fungi (also known as Deuteromycetes)
•fungi that don’t make meiospores (to our knowledge)
•reproduce only asexually (conidiophores, with conidia)
•not a true phylum but a temporary holding group
•group likely includes members of each fungal phylum, probably mostly Ascomycetes
•~17,000 species are known
•famous examples: Penicillium and the organism that causes of athlete's foot
•importance
A.decomposers
B.food rotters (can make toxins: aflatoxins in peanuts)
C.food production (flavor cheeses: Roquefort, Blue cheese made from ewes' milk)
D.produce antibiotics (ex, penicillin from Penicillium) and other drugs (cyclosporin an immunosuppressive
drug obtained from a fungus, used to prevent the rejection of grafts and transplants.)
E.plant and animal diseases (human examples: athlete’s foot and ringworm)
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21. Fig. 3.5. Imperfect Fungi
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