Characteristics of fungus Classification of fungus Structure of fungus Advantages & Disadvantages of fungus

1. Fungus
- Purvesh Mendapara

2. Definition
• Fungi are eukaryotic, saprophytic, parasitic nd
unicellular or multicellular, devoid of chlorophyll
microorganisms
• Fungi are among the most diverse organisms on
earth, and are considered only second to the
Insects in species diversity.

3. Characteristics Of Fungi

4.  Nuclear status :- Eukaryotic & Multinucleate in nature ,
Haploid(N), Diploid(2N)
 Size :- Microscopic in nature
 Distribution :- Cosmopolitan
 Nutrition :- Absence of chlorophyll so Heterotrophic &
Absorptive in nature
 Cell wall :- Well defined, typically chitinized but cellulosic in
chromastian fungi
 Thallus :- On or in the substratum and unicellular or
filamentous (mycelial), septate or non septate, typically non
motile(with protoplasmic flow through the mycelium) but
motile states may occur

5.  Cell :- Most are multicellular but unicellular or single celled
(yeasts)
 Sporocarps :- Microscopic & Macroscopic
 Food storage :- Generally in the form of lipids and
glycogen.
 Life cycle :- Simple to complex
 Reproduction :- Asexual, Sexual & Parasexual or
Holocarpic & Eucarpic
 Habit :- Ubiquitous as saprobes, symbionts, parasites
 Movement :- Do not move itself
 Occurrence :- Occurs in air, water, soil and on plants &
animals

6. Structure Of Fungi

7. Hyphae
• The vegetative bodies
of most fungi is called
thallus which
constructed of tiny
filaments called hypahe
• Tubular in shape
• Hyphae grow from their
tips
• Branched (rarely
unbranched)
• Multinucleate
Hyphae
Mycelium
Thallus

8. • Hyphae are divided into cells by internal cross walls called
septa (singular:-septum)
• Due to septa there are two types of hyphae :
1)Septate hyphae
2)Aseptate hyphae

9. Mycelium
• Aggregate or mass of hyphae or extensive, feeding web
of hyphae
• Mycelia are the ecologically active bodies of fungi
• Hardened mass of mycelium that generally serves as an
overwintering stage is known as sclerotium
Germinating
spore
Mycelium

10. Haustorium
• Outgrowth of intercellular hyphae of some parasite
which enter the host cell is called haustorium
• Modified hyphae found in parasitic fungi
• Function: Absorb nutrients from host
• Some fungi even have hyphae adapted for preying on
animals.
Haustoria

11. Septa
• Uninterrupted mass running the length of the hyphae
or the protoplasm may be intervals by cross walls called
septa.
• Septa divide up hyphae into individual discrete cells or
interconnected hyphal compartments.
• There can be various type of septa present in different
fungi, they are complete septa, perforated septa,
dolipore septa etc.
• It act as the first line of defence when part of a hypha is
damage
• Also act as structural supports

13. Cell Wall
• Fungal cell wall contain 80-90% carbohydrates the
remainder being proteins & lipids.
• Typically present, usually based on glucans, protiens and
chitin, rarely on glucans and cellulose (Oomycota).
• Glucans and chitin are components of primary wall
• Proteins are components of secondary wall
• Functions of cell wall:-
1) Protect against osmotic lysis
2) Acts as a molecular sieve
3) Binding site for enzymes

15. Cell structure
• Eukaryotic cell structure
• They have double membrane bound cell organelles like
nucleus & mitochondria, tubular endoplasmic
reticulum(ER), golgi bodies and the ribosomes.
• There are some differences from typical eukaryotic cells like
the ribosomes lying free in the cytoplasm and not attached
to the ER.
• The nuclei of some show unusual features. Lomasomes
(plasmalemasomes) appear as particles or vesicles in
pockets, formed between the cell wall and the
plasmamembrane. Their function is not yet known.
• Many smaller vacuoles or a single large vacuole may be
observed usually surrounded by the vacuolar membrane or
tonoplast.

17. Spores
• Spore means any small propagative, reproductive or survival
unit which separates from hyphae and gives rise to new
individual
• Characteristics:
• Less water content
• Lack of vacuoles
• Slow metabolism
• Small & Light
• Formed:
• Directly on hyphae
• Inside sporangia
• By Fruiting bodies
• Asexual spores are Conidia, Zoospores, Sporangiospores
(Aplanospores), Uredospores
• Sexual spores are Zygospores, Oospores, Chlamydospores,
Basidiospores

18. Nutrition

19. Nutrition
Saprophytes
Ectotrophic
Grow on the surface
of dead organic
matter
Endotrophic
Grown inside of the
dead organic matter
Parasites
Obligate
parasites
Live only as parasite
on living host
Puccinia
graminis tritici
Facultative
parasites
Usually saprophytes
but under certain
condition they
parasitize
Fusarium ,
Pythium

20. Reproduction

21. Asexual reproduction
• Methods of asexual reproduction are,
1) Fragmentation :- Detached fragment of hyphae in suitable
conditions gives rise to a new individual (Ex. Cultivation in lab)
2) Budding :- A soft zone appears on the cell wall which bulges
out constricts and finally pinches off to form a daughter cell
(Ex. Yeasts)
3) Fission :- The cell divides in transverse plan into two cells and
later formation of a cell wall inbetween
(Ex.Schizosaccharomyces)
4) Spores :- Spores are the most common method of asexual
reproduction in fungi

23. Sexual reproduction
• Methods of sexual reproduction are,
1) Planogametic copulation :- Male & Female gametes are
motile and conjugate outside the gamentangium
2) Gametangial contact :- Male gametic nucleus migrates into
the oogonium either through a pore formed at the oint pf
contact or through a fertilization tube developed by
antheridium
3) Gametangial copulation :- The entire contents of the two
gametangia fuse and become one
4) Spermatization :- Non motile spore like male structure
empties its content into a receptive female structure during
plasmogamy
5) Somatogamy :- Fusion between undifferentiated vegetative
cells or spores is called somatic copulation or somatogamy

26. Classification of fungi

27. Kingdom Fungi
(8 phyla)
• Chytridiomycota
• Zygomycota
• Ascomycota
• Glomeromycota
• Basidiomycota
• Blastocladimycota
• Neoallimastigomycota
• Microsporidia
Kingdom Chromista
(3 phyla)
• Hyphochytriomycota
• Labyrinthulomycota
• Oomycota
Kingdom Protozoa
(1 phylum, 3 classes)
• Protostelea
• Myxogastrea
• Dictyostelia
Domain Eukarya

28. Chytridiomycota – “chytrids”
• Chytrid derived from ‘chytridion’ meaning ‘little
pot’
• Smallest & Simplest fungi
• Most primitive fungi
• Distinguishing feature produce motile & whiplash
flagellum zoospores which are ideal for dispersal in
the aquatic environments mostly freshwater and
moist soils where they are commonly found
• They include both free living forms that degrade
organic material and parasites of animals & plants
• Ex. Synchytrium endobioticum

31. Zygomycota – “zygote fungi”
• Main characteristics is sexual reproduction by
zygospores. It is fusion of two gametangia
• Fungi reproduces asexually by aplanospores or conidia
sporangiospores
• Cell wall made from chitosan chitin
• Hyphae have no cross walls
• Grow rapidly
• Commonly found in soil and on decaying plant material
(decomposes)
• Divided into 2 classes: Zygomycetes & Trichomycetes
• Ex. Bread molds

34. Ascomycota – “sac fungi”
• Largest phylum of fungi having 75% of all known fungi
• The ascus & two layered cell wall are the diagnostic features of
Ascomycota. The wall has a thin electron dense outer layer &
relatively thick electron transparent inner layer.
• Septate hyphae structure
• Presence of dikaryophase in lifecycle
• Absent of flagellated structures
• Asexual reproduction by conidia
• Ascomycetes are ecologically important in freshwater, marine,
terrestrial habitats because they degrade many chemically stable
organic compounds like lignin, cellulose
• Decomposers, pathogens, and found in most lichens
• Ex. Cup fungi, morels, truffles, Brewer’s yeast(Saccharomyces
cerevisiae), ergot disease

37. Glomeromycota
• That phylum have critical ecological importance because
they are mycorrhizal symbionts of vascular plants.
Mycorrhizal fungi form important associations with the
roots of almost all herbaceous plants & tropical trees.
• Obligate symbiosis
• Formation of arbuscules in plant root cells
• Coenocytic hyphae structure present
• Large multinucleate spores with layered walls
• AM fungi form asexual spores called glomerospores which
serves as the only means of reproduction. The spores are
very large (80-400 µm)
• No evidence of sexual reproduction
• Ex. Mycorrhizae

38. Spore
Hyphae

39. EndoMycorrhizae
Ectomycorrhizae

40. Oomycota - “egg fungi”
• Also known as “Pseudo fungi”
• Cell wall made up of glucan-cellulose (rarely with minute amount of
chitin)
• Sterol in oomycota is fucosterol not ergosterol which found in true
fungi
• Diploid somatic phase
• Thick walled oospores
• Biflagellate zoospores with one tinsel type flagellum and other
whiplash type
• Mycolaminarin as storage product
• The tinsel type flagellum and mycolaminarin are key characters of
these fungi that place them in Chromista
• Oomycota radically differ from ‘true fungi’ in lysine biosynthetic
pathway.
• Ex. Pythium, Phytophthora, Albugo

43. Basidiomycota – “club fungi”
• Contain 30000 species which is 37% of true fungi These
recognized as the highest evolved group of fungi
• Most conspicuous fungi in environment
• The most important feature is production of basidiospores
which are sexual spores. But being internal the
basidiospores externally on the basidium
• Long-lived dikaryotic mycelia
• Other features included :
• The highly developed dikaryophase of the thallus
• The formation of clamp connection on the dikaryotic
hyphae
• The presence of the dolipore septa in some and
• Double layered cell wall present
• Ex. Mushrooms, shelf & bracket fungi, puffballs, rusts &
smuts disease

46. Symbiotic association

47. • Mutualism:-
Two organisms living together, both benefit (Ex.
Lichen, Mycorrhizae)
• Parasitism:-
In which one of the two partners lives at the
expense of the other means one organism benefits, the other
is harmed or killed slowly (Ex. Insects are infected with
fungus)
• Saprobes:-
Obtain nutrients from nonliving organic material
or from the remains and byproducts of organisms (Ex.
Decomposers fungi)

49. Advantages of fungi

50. 1) Food production (Edible mushroom)
2) Biological control (Trichoderma viride, Beauveria
bassiana)
3) Enzyme activity (Cheese ripening)
4) Metabolites (Plant growth hormones)
5) Biotransformation (Yeast formation)
6) Produced antibiotics (Penicillium notatum)
7) Produced some organic acids (citric acid, gluconic
acid, fumaric acid)
8) Produced some industrial enzyme (invertase,
pectinase, proteases)

52. Disadvantages of fungi

53. 1) Spoilage (grains, fruits, vegetables)
2) Allergic responses
3) Mycotoxins (Aflatoxins, Ochratoxin)
4) Fungal infection in animal & human (ringworm)
5) Plant diseases (rust, smut, powdery mildew
disease)

55. References
• An introduction to fungi. H C Dube
• Prescott’s microbiology. Willey, Sherwood,
Woolverton
• Brock biology of microorganisms. T.Madigan