1. 1
What are fungi
Raed A. Haleem
PhD in Plant Pathology – Mycology
University of Duhok – College of Agriculture
Plant Protection department
raed.haleem@uod.ac
2. What are fungi?
Fungi and fungi-like
organisms are classified
into three different
kingdoms, reflecting their
true genetic diversity.
Yet they are considered
together in this course
because many aspects of
their life cycles, nutrition
and pathology are similar. 2
3. About 80 000 to 120 000 species of
fungi have been described to date,
although the total number of species is
estimated at around 1.5 million
3
5. Based on their lifestyle, fungi may be
circumscribed by the following set of
characteristics-
5
6. 1. NUTRITION.
Heterotrophic (lacking
photosynthesis), feeding by
absorption rather than
ingestion.
Release digestive enzymes to
break down organic material
or their host.
Store food energy as glycogen
6
BREAD MOLD
7. ABSORPTIVE HETEROTROPH
Fungi get carbon from organic sources
Tips of Hyphae release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Digested material is then used by
the hypha
Nucleus
8. 2. VEGETATIVE STATE.
On or in the substratum,
typically as a non-motile mycelium of
hyphae showing internal protoplasmic
streaming.
Motile reproductive states may occur.
8
9. HYPHAE
Hyphae either
septate or non-
septate
(coenocytic),
Tubular shape.
Hyphae are usually
branch extensively,
and the collective
mass of hyphal
filaments is called a
mycelium 9
10. HYPHAL GROWTH FROM SPORE
Mycelia have a huge
surface area
More surface area aids
digestion & absorption
of food
mycelium
Germinating spore
10
11. SEPTA
The Oomycota and Zygomycota generally
have aseptate hyphae in which the nuclei
lie in a common mass of cytoplasm. Such a
condition is described as coenocytic
11
12. Septa have pores
for movement of
cytoplasm Form
network mycelia
that run through
the thallus
(body)
12
13. .In contrast, Ascomycota and
Basidiomycota and their associated
asexual states generally have septate
hyphae in which each segment contains
one, two or more nuclei.
13
14. It should be noted that septa, where
present, are usually perforated and allow
for the exchange of cytoplasm or
organelles .
Not all fungi grow as hyphae. Some grow
as discrete yeast cells which divide by
fission or, more frequently, budding .
14
15. HYPHAE
Stolons –
horizontal hyphae
that connect
groups of hyphae
to each other
Rhizoids – rootlike
parts of hyphae
that anchor the
fungus
15
STOLON
RHIZOIDS
16. Morphologically,
fungi range from
small,
inconspicuous
yeasts and molds
to large,
conspicuous
mushrooms,
puffballs, and
bracket fungi.
16
UNICELLULAR YEAST
Penicillium moldPuffball
17. Some are single cells (e.g., the yeasts),
but most exist as filaments known as
hyphae (singular, hypha).
17
18. 3. CELL WALL.
Typically present, usually based on
glucans and chitin, rarely on glucans and
cellulose (Oomycota).
18
19. 4. NUCLEAR STATUS
Eukaryotic, uni- or multinucleate,
the thallus being homo- or
heterokaryotic, haploid, dikaryotic or
diploid, the latter usually of short
duration (but exceptions are known from
several taxonomic groups).
19
20. If the nuclei are genetically identical,
as in a mycelium derived from a single
uninucleate spore, the mycelium is said
to be homokaryotic,
20
21. but cell or mycelium contains nuclei of
different genotype, e.g. as a result of
fusion (anastomosis) of genetically
different hyphae, it is said to be
heterokaryotic
21
22. A special condition is found in the
mycelium of many Basidiomycota in which
each cell contains two genetically
distinct nuclei.This condition is
dikaryotic, to distinguish it from mycelia
which are monokaryotic.
22
23.
24. Some fungi show
dimorphism
May grow as MYCELIA
or a YEAST –LIKE
state (Filament at 25oC
& Round at 37oC)
24
Dimorphic Fungi
25. Intermediate stages between yeast cells
and true hyphae also occur and are termed
pseudohyphae .
25
27. 6.REPRODUCTION.
27
The following reproductive
events may occur:
- sexual (i.e. nuclear
fusion and meiosis)
- parasexual(i.e. involving
nuclear fusion followed
by gradual de-
diploidization)
- asexual(i.e. purely
mitotic nuclear division).
28. 7. PROPAGULES.
These are typically
microscopically
small spores
produced in high
numbers.
28
Spores come
in various
shapes
29. SPORES
Spores are an adaptation to life on
land
Ensure that the species will
disperse to new locations
Each spore contains a reproductive
cell that forms a new organism
Nonmotile
Dispersed by wind
29
30. Spores may be Formed:
Directly on hyphae
Inside sporangia
In Fruiting bodies
Amanita fruiting body
Pilobolus sporangia
Penicillium
hyphae
31. 8. SPOROCARPS ( FRUITING BODIES)
Microscopic or
macroscopic and
showing
characteristic
shapes but only
limited tissue
differentiation
33. ASEXUAL REPRODUCTION
Fruiting Bodies are modified hyphae
that make asexual spores
An upright stalk called the
Sporangiosphore supports the spore
case or Sporangium
33
35. 9. HABITAT.
Ubiquitous in
terrestrial and
freshwater
habitats, less
so in the marine
environment.
36. 10. ECOLOGY.
Fungi are heterotrophic,
obtaining organic material
from their environment.
37. 10. ECOLOGY.
Important ecological roles as
- saprotrophs,
- mutualistic symbionts,
- parasites,
- hyperparasites.
38. Parasites obtain nutrients from a living
host and ultimately harm that host
Mutualistic symbionts obtain nutrients
from a living host while providing some
benefit to that host
Saprobes obtain nutrients from non-
living organic material or from the
remains and byproducts of organisms
(Decomposers)
48. FOOD
Mushrooms, the fruiting
bodies of certain fungi,
are widely used as food.
Button mushrooms,
Agaricus bisporus, are
the mushrooms of
commerce that lend
flavor to Cream of
Mushroom soup
48
49. BENEFIT
Shitake, Lentinus edodes, is the major
cultivated mushroom of Asia, grown for
centuries on oak logs, now often grown on
a sawdust mixture.
49
50. Other widely grown mushrooms include;
- Oyster mushrooms, Pleurotus ostreatus;
- Enokitake, Flammulina velutipes;
- Truffles, Tuber melanosporum or
- Tree Ears, Auricularia auricular;
50
53. 53
Truffles,
Tuber melanosporum
= The Black truffle (Tuber melanosporum) can exceed
US$ 1,000 a Kilogram
= The white truffle (Tuber magnatum), which only
grows wild, reaches US$ 3,000 a Kilogram.
54. BENEFIT
The yeasts are members of the fungus
kingdom, and countless yeasts are used to
process food.
They are generally one-celled, but can
reproduce by budding, which sometimes
produces long strings of yeast.
54
55. BENEFIT
Saccharomyces cerevisiae is a yeast that
people have used for thousands of years.
It is called bakers yeast or brewers
yeast, depending on use, and is also the
source for nutritional yeast. It makes wine
and bread.
55
56. Soy sauce, miso, sake, and rice vinegar
depend on Aspergillus oryzae for
fermentation. Fungi produce the blue veins
in some cheese.
Tempeh is manufactured with Rhizopus
oligosporus.
Kefir is produced by a symbiotic colony of
various yeasts and bacteria.
56
58. Penicillium is the mold that many
know as a producer of penicillin.
It is a mold that literally has
saved lives because of the useful
antibiotic produced.
58
59. A number of species of
Penicillium,
P. roquefortii and
P. camembertii, are
familiar to cheese
lovers
59
61. BENEFIT
Fungi are also sometimes used to protect
the human food supply.
Beauveria bassiana, for example, is a
fungus found in soils worldwide. It acts as
a parasite on some insects. It is currently
used against termites, whitefly, and some
beetles.
61
64. BENEFIT
- Medicine
- Some vitamins are also produced through
fermentation, along with anticancer and anti-
cholesterol drugs.
Griseofulvin, an antifungal, can be produced by
fermentation using Khuskia oryzae.
64
Nail fungus
Trichophyton rubrum
65. BENEFIT
- Medicine
Reishi mushrooms are being studied as
cancer-fighters.
Fusidic acid is a controversial compound
derived from the fungus Fusidium
coccineum. It appears to have
bacteriostatic action against
Staphylococcus
65
67. 67
Organic acids produced by fungi.
Organic acid Source
Citric acid Aspergillus niger
Fumaric acid Rhizopus nigricans
Gluconic acid Aspergillus niger
Itaconic acid A. terreus
Kojic acid A. oryzae
68. SCIENCE
Saccharomyces cerevisiae (bakers yeast) was
the first eukaryotic genome ever sequenced.
Yeasts are handy for genome research because
they reproduce quickly and are relatively easy
to modify genetically, and yet their cells
share many characteristics of plants and
animals.
This particular yeast is thought to have 23% of
its genetic material in common with humankind.
68
69. Other fungi that have been important in
research include Neurospora crassa,
a bread mold.
69
70. Edward Tatum and George Wells Beadle
used it in experiments that won them a
Nobel Prize.
They irradiated the mold, to cause
mutations. Then they noted the specific
ways that these broken genes damaged
the mold's metabolism.
70
71. Their observations led them to
formulate the "one gene, one enzyme"
hypothesis that each gene produces a
specific enzyme.
71
76. 2)Mycotoxins.
Several secondary metabolites are produced by
fungi.the most important mycotoxins are:
1- Aflatoxins produced by Aspergillus flavus ,
A. parasiticus. The toxin is carcinogenic.
2- Ochratoxin A. produced by Aspergillus
ochraceus , A, carbonarius. The toxin is causing
Kidney failure.
76
77. 3- Fumonisins, Zeraleonene and T2-toxin are
produced by Fusarium species. These toxins
are carcinogenic and mutagenic.
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79. 4) ANIMAL AND HUMAN MYCOSES.
Fungi are responsible for several animal
and human diseases.
Some of them are causing skin diseases
and hence called ringworm or tinea and
the causal pathogens are called
dermatophytes such as Trichophyton
mentagrophytes and Microsprum canis.
79
80. Yeast fungi such as Candida albicans are
responsible for several superficial and
systemic diseases.
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