Mycology

1. Mycology • Myco = fungus • ology = the study of

2. Classification of Fungi • Domain Eukarya • Kingdom Fungi • Phylum -mycota • Class -mycetes • Order -ales • Family -aceae • Genus • Species Domineering King Philip Can Order Five Green Shirts

3. Pizza with Agaricus bisporus White Button Mushroom • DomainEukarya • KingdomFungi • Phylum Basidiomycota • Class Hymenomycetes • Order Agaricales • FamilyAgaricaceae • GenusAgaricus • SpeciesAgaricus bisporus

4. Fungi are probablymore closely related toanimals that to eitherplants or protists!

5. Characteristics of Fungi • Eukaryotic • Non vascular organisms • Reproduce by means of spores • Both sexual (meiotic) and asexual(mitotic) spores may be produced • Typically Non Motile • Alteration of generations • like plants

6. Molds:Microscopic threads of cells (hyphae) Vegetative Body Yeasts:Unicellular • Hyphae a system of thread like, walled, more or less cylindrical cells singular hypha

7. Hyphal Growth

8. Cell walls • simple chemical composition • fungi cell walls are mostly chitin • chitin synthesized by fungi • plant cell walls are mostly cellulose • (plus lignin in secondary walls)

9. Chitin Resists bacterial degradation Used in sutures

10. Cellulose

11. Cell membranes • ergosterol, a unique sterol • mammaliam membranes have cholesterol

12. Fungal Traits • Heterotrophs • (“other feeding,” ) must feed on preformed organic material. • Fungi digest then ingest • produce exoenzymes • Animals ingest then digest • Food stored as glycogen • animal store glycogen • plants store starch • Lysine biosynthesis • different pathway

13. More Fungal Traits • Cytoplasmic ultrastructure • similar to plants cells • significantly different organelles and structures • Mitosis is generally accomplished without dissolution of the nuclear envelope • Tubule protein • different type formed in microtubules during nuclear division • Very small nuclei • little repetitive DNA

14. Lack of Chlorophyll profoundly affects the lifestyle of fungi • not dependent on light • can occupy dark habitats • can grow in any direction • can invade the interior of the substrate with absorptive filaments

15. Vegetative Growth

16. Anatomy of Yeast

17. Nutritional Status of Fungi • Saprophytes • Parasites • Mutualists (symbionts)

18. Saprophytes • use non-living organic material • important scavengers in ecosystems • Fungi are important in recycling Carbon, Nitrogen, and essential mineral nutrients. • Along with bacteria

19. Fungal Parasites • use organic material from living organisms, harming them in some way. Adhesive Knobs

20. Fungal Parasites • range of hosts: from single celled diatoms to fungi to plants to animals to humans. Trapped nematode

21. A fungal predator Oyster fungus traps a nematode in a ring of hyphae

22. Mutualists (symbionts) • Fungi that have a mutualistically beneficial relationship with other living organisms. • Mycorrhizae: associations of fungi with plants roots • Lichens: associations of fungi with algae or cyanobacteria

23. Mycorrhizae • Plant- Fungal Symbiont • more than 90% of plants in nature have a mycorrhizal symbiont. • Mycorrhizae forms • ectomycorrhizae • endomycorrhizae Myco= fungus rhiza= root

24. Types of Mycorrhizae • Ectomycorrhizae-- fungus forms a sheath outside the root • Endomycorrhizae--vesicular-arbuscular mycorrhizae (VAM), no sheath • Orchid mycorrhizae are a special type

25. Ectomycorrhizae • Fungus forms a sheath around the root, with hyphae emanating through the soil, greatly increasing the surface area • fungus penetrates between cells of the cortex to facilitate nutrient exchange • fungus is almost always a Basidiomycota, although a few are Ascomycota species dichotomous ectomycorrhizas (upper) and mycelial strands (lower) of Amanita muscaria on Pinus strobus.

26. Endomycorrhizae • AKA vesicular-arbuscular mycorrhizae (VAM) • fungus does not form a sheath around the roots • fungus penetrates the cortical cells, • but does not penetrate the cell membrane • fungus is a member of Zygomycota • more common than ectomycorrhizae hyphae and arbuscules of an endomycorrhizal fungus in Asarum (wild ginger) (see Fig 15 in Brundrett & Kendrick 1988 Can. J. Bot. 66: 1153)

27. Lichens • symbiosis between a fungus and an alga or cyanobacterium • usually neither can survive on its own most of the fungi involved are Ascomycota -- a few are Basidiomycota

28. Lichen Ecology • Lichens can grow in very inhospitable environments-- on rocks, sides and branches of trees, gravestones • Lichens are very sensitive to air pollution, especially sulfur and nitrogen, and so they are natural indicators of air quality • Lichens grow extremely slowly,~ 1-2 mm per year

29. Lichen Uses • lichens break down rocks into soil • food source for caribou and reindeer on the tundra, reindeer lichens • natural dyes, tweed • one lichen was used by the “pioneers” as a wolf killer. • There is evidence that the manna referred to in the Bible was really a lichen, Lecanora esculenta, that blew down from the mountains

30. Commensalism • One organism uses another to get a better position in the environment • neither organism is harmed • there is usually no physiological interaction between the two organisms • most often for photosynthesis • advantages in shaded areas • very common in rainforests • may also be for reproductive advantages • some fungi “climb” up trees and vines (while not gaining nutrition from them) in order to release their spores from as high a perch as possible

31. Fungi are verysuccessful Organisms • genetic plasticity • physiological versatility. • Spores • enormous numbers • effectively spread over a wide area. • asexual (mitotic) and sexual (meiotic) spores. • spores can remain dormant until conditions become favorable • sometimes years (King Tut Beer)

32. Many fungi are harmfulto human interests • can cause human disease, either directly or through their toxins • an cause diseases of plants and animals that humans are interested in (e.g. crops, etc.) • cause rot and contamination of foods • can destroy almost every kind of manufactured good • with the exception of plastics and some pesticides

33. Many fungi are veryuseful to humans • yeasts-- baking and brewing • antibiotics--- e.g. penicillin & cephalosporin • other drugs-- e.g. cyclosporin • many organic acids are commercially produced with fungi-- e.g. citric acid in Coke is produced by an Aspergillus • steroids and hormones--- e.g. the pill • certain “stinky” cheeses-- e.g. blue cheese, Roquefort and Camembert

34. Fungi are importantexperimental organisms • easily cultured, occupy little space, multiply rapidly, short life cycle. • study metabolite pathways • study growth, development, and differentiation • mechanisms of cell division and development • microbial assays of vitamins and amino acids • genetics-- e.g. “one gene one • enzyme” in Neurospora won • Beadle and Tatum the Nobel • prize

35. Asexual and SexualReproduction in fungi • Teleomorph: The sexual (perfect, meiotic) state of a fungus • Anamorph: The asexual (imperfect, mitotic) state of a fungus • many fungi can have both states, especially Ascomycota • most have either one or the other

36. Sexual Reproduction(teleomorph) • Sexual reproduction involves the union of two compatible nuclei (not necessarily in gametes) with a subsequent meiotic division yielding recombinant progeny. • There are a variety of methods by which this is accomplished, and this is the basis for most systematics • Life cycles-there is a lot of variation within the fungi

37. Sexual Reproduction • All sexual fungal life cycles consist of: • Plasmogamy—cell fusion • Karyogamy—nuclear fusion • Meiosis

38. Gametangi • The sex organs in fungi are called gametangia (sing. gametangium) • May be differentiated into distinguishable male and female organs • Bear either differentiated sex cells (gametes) or one or more "gamete nuclei.”

39. Homothallic vs Heterothallic • Homothallic: a single mycelium that is capable of reproducing sexually • Heterothallic: two mycelia are required to reproduce sexually • Heterothallic forms may have both male and female gametangia on the same mycelium, but they are incompatible with one another.

40. Major Fungal Phyla • Chytridiomycota • Zygomycota • Ascomycota • Basidiomycota • “Deuteromycetes” based on the method of producing sexual spores

41. Chytridiomycota • sexual and asexual spores • motile spores • posterior flagella

42. Chytridiomycota Flagellum has whip-like motion

43. Zygomycota Sexual spores are thick walled resting spores called zygospores asexual spores are borne internally in asporangium

45. Ascomycota Sexual spores borne internally ina sac called an ascusAsexual spores are borneexternally as conidia

46. Ascomycota

47. Basidiomycota Sexual spores borne externally ona club-shaped structure called a basidium. Usually no asexual spore

48. 5ft World’s largest Basidocarp At Yew Gardens

49. Basidomycota life cycle

50. “Deuteromycetes” No known sexual state,usually reproduces by conidia as asexual state