1. Chapter 19 Señora Ettinger
Fungi
Chapter 19
Señora Ettinger

2. Answer these questions:
How do fungi differ from other organisms?
How does the lifestyle of a fungus enable it to obtain food?
What factors make each phylum of fungi distinctive?
How do fungi affect humans?

3. Look at page 406 of your textbook
What do you see in the main picture on this page?
Read the caption. What is really shown in the picture?
Are “fungus flowers” made of fungus?
Why would a fungus go to all the trouble of making a plant imitate a flower?

4. Page 406 continued
Do you think this fungus hurts or helps the rock cress plant?
Would you guess that fungi could flower on its own?

5. Characteristics of Fungi
Cell structure
Lifestyle
Food acquisition
Habitat
Cell walls

6. Fungi—plants?
Cell wall
Mitosis
Chlorophyll
Dikaryon stage

7. Other characteristics of Fungi
Heterotrophs
Digest food outside its body by secreted enzymes then absorb the nutrients
Typically terrestrial
Key decomposers of plant material
Most derive their nutrition from plants
Cell walls made of chitin

8. Fungal Niches
Saprobes-
Parasites-
Symbiotic
Mutuals

10. Fungi Structures, page 408, draw and label figure 19-2 here:

11. Hyphae structure, draw Figure 19-3, page 408 here:

12. Hyphae The dominant structure of fungi
Long, multinucleated, typically multicelled, one-cell thick fungal tissue
Typically hidden from sight since fungi grow their hyphae into their food
Serve as vascular channels along which nutrients are passed

14. Mycelium
What is it?

18. Septa
What is it?

20. Septate

21. coenocytic

22. “Recess” Read Armillaria ostoyae

23. Part 2:
Reproduction
Fungal Divisions

24. Reproduction
All nuclei are haploid except for zygote nuclei (except some Chytridiomycota)
In the sexual reproduction, hyphae of two different mating strains meet and fuse but the two types of nuclei may coexist without fusion for most of the life of the fungus
Fungi reproduce by relasin spores

25. Reproduction Monokaryotic compartment has a single nucleus
Dikaryotic compartment has two genetically distinct nuclei
Heterokaryotic hyphae have two kinds of genetically different nuclei
Homokaryotic hyphae have genetically similar nuclei

26. Reproductive Structures
Sporangia:
Gametangia:
Conidia

27. Fungal Divisions
Plant-like, this groupings are called divisions instead of phyla
Presently differentiated from slime molds and water molds

28. Chytridiomycota

29. Fungal Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota
Deuteromycota (Fungi imperfecti) Your book doesn’t mention this one.

30. Chytridiomycota

31. Chytridiomycota

32. Read Modern Genetics Versus Ancient Frog-Killing Fungus.
Write a synopsis in the space provided.
Be ready to answer questions

33. Chytridiomycota
Zygomycota

34. Zygomycota: What does the name imply?

35. Zygomycota some characteristics

36. Zygomycota Non-reproductive hyphae lack septa
Include the common bread molds
Produce zygospores

37. Life Cycle and Sexual Reproduction
Sexual reproduction is via fusion of multinucleate gametangia
May occur between same or different mating types
Massive, haploid zygospore forms around diploid zygote nuclei
Meisois occurs during germination

39. Asexual Reproduction Haploid spores are produced within sporangia
Sporangium forms at the tip of erect hypha, with separating septum
Spores shed above substrate, dispersed by wind

40. Chytridiomycota
Ascomycota

41. Ascomycota
Beneficial
Harmful forms

42. Yeast

43. Mold

44. Morels
True Morel
False Morel

45. Truffles

46. Truffles

47. Cup Fungi

48. Chestnut Blight

49. Chestnut Blight

50. Dutch Elm Disease

51. Ascomycota
Has a characteristic reproductive structure called an ascus.
A diploid zygote forms within ascus.
Asci form on ascocarp of densely interwoven hyphae

53. Sexual Reproduction Ascogonia are female, have trichogyne
Antheridia are male, fuse with trichogyne
Male nuclei travel to ascogonium to pair with opposite nuclei
Heterokaryotic hyphae arise from point of fusion
An ascus containing two nuclei forms at the hyphal tip

54. Sexual Reproduction
Nuclei within the ascus fuse, forming diploid zygote which immediately undergoes meiosis
Four haploid daughter nuclei are the result.
These haploid daughter nuclei undergo mitosis to form 8 ascospores
The ascospores are then released, in most cases by the ascus bursting.

55. Asexual Reproduction
Conidia are produced at the ends of conidiophores. Conidiophores are the stalk-like vertical growths on the hyphae. Spores are formed at the end of the conidiophores and are separated by septum and are called conidia.
The spores are released and then germinate

56. Chytridiomycota
Basidiomycota

57. Basidiomycota
Includes mushrooms, jelly fungi, puffballs, rusts and smuts
Includes edible as well as poisonous varieties

58. Mushrooms

59. Mushrooms

60. Mushrooms

61. Jelly Fungus

62. Jelly Fungus

63. Puffballs

64. Rusts

65. Rusts

66. Corn Smut

67. Basidiomycota
Characteristic reproductive structure is called a basidium.
Syngamy occurs within basidium
Meiosis occurs immediately, forming four haploid basidiospores
Four basidiospores are borne on one basidium

69. Sexual Reproduction Spore germinates forming homokaryotic hyphae
Eventually septa form between nuclei of primary mycelium
Dikaryotic, heterokaryotic secondary mycelium forms when hyphae of different mating types fuse
Basidiocarps form of completely dikaryotic hyphae
Basidia line the gills of typical mushrooms

70. Deuteromycota
Commonly called Fungi Imperfecti because they exhibit only asexual reproduction
Mostly ascomycetes, few zygomycetes and basidiomycetes
Many are human and plant pathogens
Others produce important chemicals such as penicillin

71. Parasexuality
Parasexuality occurs when two different hyphae fuse forming heterokaryotic hyphae. The two different nuclei may exchange portions of chromosomes between nuclei.
Provides a certain amount of genetic recombination.

72. Fungal Associations
Lichens
Mycorrhizae

73. Lichens Mostly ascomycetes with green algae and/or cyanobacterium
Specialized hyphae penetrate or envelop photosynthetic cells
Fungal chemical signals direct photosynthetic metabolism
Could be considered a form of controlled parasitism

74. Lichens
Reproduction of the fungal portion is via normal fungal sexual reproduction
Reproduction of the photosynthetic component is asexual
The lichen as a whole can fragment and be transported by wind… to a new location to form a new individual

75. Lichens Can inhabit cold, dry, generally harsh environments
Help break rock surfaces and prepare habitat for other organisms
Coloration of lichen protects photosynthetic partner
Can survive adverse conditions by nearly halting metabolism

81. Mycorrhizae Most plant roots associated with certain fungi
Fungus aid in transfer of soil nutrients into roots
Plant provides organic carbon to fungus
Arbuscular mycorrhizae and ectomycorrhizae

82. Arbuscular Mycorrhizae
Hyphae penetrate outer cells of root
More common mycorrhizae, generally a zygomycetes
May increase yield of crops with less energy input

83. Ectomycorrhizae Hyphae surround, but do not penetrate roots
Less common, mostly basidiomycetes, some ascomycetes
Characteristic symbiont of shrubs and trees

84. Advantages Plants more resistant to drought, cold and harsh conditions
May provide better protection against acid precipitation
Prevent accumulation of toxic metals
Speed germination of orchid seeds
Provide better growth in poor soils