1. True Fungi break down dead organic material provide numerous drugs
foods like mushrooms
Plant and animal diseases

2. Characteristics of fungi
Fungi exist primarily as filamentous threads, the hyphae, forming a mass, a mycelium. Normally never see the mycelium, only the fruiting bodies.
Cell walls contain chitin.*
Reproduction is due to fusion of hyphae*
Fungi are heterotrophic by absorption

3. Groups of fungi Chytridiomycota (chytrids) Zygomycota (bread molds)
Ascomycota (yeasts and sac fungi)
Basidiomycota (club fungi)
Deuteromycota (asexual forms of ascomycetes and basidiomycetes)

4. Generalised Life cycle of fungi
Meiosis
to give spores
Fusion of
hyphae*
Nuclear
fusion
Dikaryotic
mycelium
gives fruiting
body
Diploid
stage
Haploid
mycelia
of different
mating
types
With the exception of the chytrids, the life cycle follows the same generalised pattern. Haploid hyphae fuse to form a mycelium which contains nuclei from the two hyphae. The duration of this ‘dikaryotic’ phase is different in the differing groups of fungi and therefore characteristic.
At some stage the nuclei fuse to form a diploid cell, and there is usually immediate meiosis to give spores.
Not in chytrids*
Zygomycetes - V. small fruiting body
Ascomycetes - small fruiting body
Basidiomycetes - long-lived hyphae then
a large fruiting body

5. Comparison of different groups

6. Chytridiomycota (chytrids)
The oldest fossil fungi so far known and may form a ‘missing link’ with protists.
Flagellated zoospores fuse, their nuclei fuse then immediate meiosis to give spores

7. Zygomycota (bread molds)
Important decomposers
Dominant haploid phase with dikaryon restricted to formation of zygosporangium
asexual spores are produced

8. The life cycle of a zygomycete
Spores produced by mitosis
Zygospores
Spores produced
by meiosis
Sporangium
forms by
mitosis
The life cycle of a zygomycete
Spores germinate
to give mycelium
Coenocytic mycelia
of 2 mating types
Hyphae
grow
to each
other
Gametangia
develop
Zygosporangium
develops
Zygosporangium
formed

9. Ascomycota (yeasts and sac fungi)
Sexual spores (ascospores) are produced in a specialized sac-like structure called an ascus on the surface of an ascocarp.
Reproduced asexually by conidia
Decomposers that include economically important foods such as truffles and Morels and pests such as powdery mildews and ergots. Yeasts used in baking and brewing.

10. Life cycle of an ascomycete
Nuclear fusion then
Ascospores in asci
by meiosis
Life cycle of an ascomycete
Haploid
septate hyphae
Anther-
idium
(‘male’)
Asco-
gonium
‘female’
Dikaryotic hyphae

11. Sporing structures (ascocarps)
A vegetative layer of ‘sterile’ dikaryotic hyphae (2 nuclei) forms the body of the ascocarp with a layer of asci on the surface (produce spores)

12. Sporing structures

13. Tissues within the ascocarp
Cup fungi
Morels
Flask fungi
Sterile body of ascocarp formed from dikaryotic hyphae
Layer of asci

14. Basidiomycota (club fungi)
Septate hyphae
Produce long-lived dikaryons (mycelia where the cells have 2 nuclei)
Produce sporing structures, the basidia, on basidiocarps.
Wood rotting fungi
Rusts
Smuts
Mushrooms
Puffballs
Life cycle a bit like ascomycetes, but individual spores produced

15. Yeasts Unicellular forms of ascomycetes and basidiomycetes.
Some reproduce sexually some don’t.
Baking
Brewing
Human pathogens e.g. Candida

16. Deuteromycota (asexual forms of ascomycetes and basidiomycetes)
No sexual stages known and propagate solely by spores called conidia on structures called conidiaphores.
Includes commercially important species such as Penicillium (gives penicillin from fungal fermentations)
Conidia
Conidiophore
Mycelium

17. Lichens
Lichens are unusual creatures. A lichen is a combination of two organisms which live together intimately. Most of the lichen is composed of fungal filaments, but living among the filaments are algal cells, usually from a green alga or a Cyanobacterium.