1. Kingdom Fungi

2. Kingdom Fungi contains more than 81,000 known species (most terrestrial)
All fungi are eukaryotes
Cells contain
Membrane-enclosed nuclei
Mitochondria
Other membranous organelles

3. Fungi are heterotrophs
Most are decomposers
Some are parasites
Found universally wherever organic material is available

4. Optimum pH for most species is ca. 5.6
Some can tolerate pH ranges from 2 to 9
Many can grow in
Concentrated salt solutions
Sugar solutions, e.g. jelly
Fungi tolerate wide temperature range

5. Characteristics of fungi
Enclosed by cell walls at some stage in life cycle
Most fungi have cell walls consisting of complex carbohydrates including chitin

6. Two main types: molds and yeasts
Vegetative body plan of molds consists of hyphae
Hyphae form mycelium
Some hyphae are coenocytic
Some are divided by septa into individual cells containing one or more nuclei
Yeasts are unicellular

7. Fungus body plan

8. Most fungi reproduce by spores, either nonmotile or motile
Spores usually produced on
Specialized aerial hyphae
Aerial hyphae of some fungi form fruiting bodies
Fruiting structures

9. Germination of a spore to form a mycelium

10. Germination of a fungal spore
Hypha emerges
Mycelium infiltrates growth medium
Mycelium degrades complex organic compounds to small organic molecules

11. Fungi that do not fit these phyla classified as Deuteromycota
Four main phyla
Chytridiomycota
Zygomycota
Ascomycota
Basidiomycota
Fungi that do not fit these phyla classified as Deuteromycota

13. Chytridiomycetes are the most primitive fungi alive today
Produce flagellate cells at some stage in their life cycle
No other fungal phyla are flagellate

14. Fungal evolution

15. Distinguishing characteristics of chytridiomycetes
Motile cells have a single, posterior flagellum
Reproduce sexually and asexually
Are parasites or decomposers

16. Life cycle of Allomyces
Has an alternation of generations: spends part of its life as a haploid thallus and part as a diploid
Haploid thallus bears male and female gametangia
When a flagellate male gamete fuses with a flagellate female gamete, result is a diploid thallus

17. Life cycle of Allomyces arbuscula

18. Distinguishing characteristics of zygomycetes
All produce zygospores
Hyphae are coenocytic
Septa form to separate the hyphae from reproductive structures

19. Life cycle of Rhizopus stolonifer
Hyphae meet to form gametangia
Gametangia unite, the nuclei fuse
A single zygospore develops
Meiosis occurs, zygospore germinates
Emerging hypha develops a sporangium
Spores are released

20. Life cycle of Rhizopus stolonifer

21. Distinguishing characteristics of ascomycetes
Sexual spores are produced in asci
Hyphae usually have septa, but cytoplasm is continuous

22. Life cycle of a typical ascomycete
Gametangia fuse, forming dikaryotic hyphae
Asci develop from dikaryotic hyphae
Asci are incorporated into an ascocarp

23. Life cycle of a typical ascomycete, cont.
In each ascus, the nuclei fuse to form the zygote
Meiosis occurs, forming four haploid nuclei
Mitosis occurs, producing eight haploid nuclei

24. Life cycle of a typical ascomycete, cont.
Each haptoid nuclei becomes incorporated into an ascospore
When ascospores are released, they germinate and form new mycelia
Asexual reproduction involves the formation of haploid conidia

25. Life cycle of a typical ascomycete

26. Distinguishing characteristics of basidiomycetes
Develop basidia
Each basidium is an enlarged hyphal cell
Four basidiospores develop on the tip of the basidium

27. Basidia line the gills of Omphalotus olearius

28. SEM of a basidium

29. Life cycle of basidiomycetes
When a hypha of a primary mycelium encounters another monokaryotic hypha of a different mating type, the two hyphae fuse
The two haploid nuclei remain separate

30. Life cycle of basidiomycetes, cont.
A secondary mycelium is produced
The n +n hyphae of the secondary mycelium grow
The hyphae form buttons along the mycelium
Button develops into a basidiocarp

31. Life cycle of basidiomycetes, cont.
In the young basidia, haploid nuclei fuse, forming diploid zygotes
Meiosis takes place, forming four haploid nuclei
Extensions of the basidium develop

32. Life cycle of basidiomycetes, cont.
The nuclei and some cytoplasm move into the basidium
Each extension of the basidum becomes a basidiospore
A septum forms, separating basidiospore from the rest of the basidium

33. Life cycle of a typical basidiomycete

34. Distinguishing characteristics of deuteromycetes
Are all similar, but are probably polyphyletic
Do not have a common ancestor

35. Most deuteromycetes have no sexual stage during their life cycle
Some have lost the ability to reproduce sexually
Others reproduce sexually only rarely
Most reproduce only by means of conicidia

36. Lichen
Dual organism: symbiotic association between a phototroph and a fungus
Phototrophic component is either a green alga, a cyanobacterium, or both
Fungus is an ascomycete or a basidiomycete

37. Cross section of a typical lichen

38. Typically, lichens exhibit one of three different growth forms
Crustose
Foliose
Fruticose
Lichens reproduce mainly asexually

39. Crustose, foliose, and fruticose growth forms
Crustose Lichens (Bacidia, Lecanora)
Foliose lichen (Parmelia)

40. Ecological significance of fungi as decomposers
Absorb nutrients from organic wastes
Release water, CO2, and mineral components of organic compounds
These elements are recycled

41. The ecological role of mycorrhizae
Mycorrhizal fungus decomposes organic material in soil
Benefit plants by increasing their absorptive surface area

42. The ecological role of mycorrhizae, cont.
Roots supply fungus with sugars, amino acids, and other organic substances
Scientists have measured movement of organic materials from one tree species to another

43. Western red cedar grown without mycorrhizae

44. Western red cedar grown with mycorrhizae

45. Economic and medical importance of fungi
Beverages
Food
Medicine
Chemicals

46. Fungal diseases of plants
Dutch elm disease
Chestnut blight fungus
Smuts and rusts
Verticillium wilt

47. Fungal diseases of humans
Ringworm and athlete’s foot
Histoplasmosis
Aspergillosis
Cancer (contributory factor)
Sick building syndrome (contrib- utory factor)