Introduction to the Fungi

1. Introduction to the Fungi

2. Goals for today What are fungi? How do fungi interact with other organisms? What are the different types of fungi? Why should you care about fungi?

3. Characteristics of Fungi 1. Heterotrophic saprobes – cells of hyphae secrete digestive enzymes and absorb products of digestion 2. Cell wall made of chitin - a polysaccharide with added nitrogen group 3. Hypha - filamentous body - forming mycelial mat - each hypha is composed of a chain of cells with or without separating septa

4. Fungi have both asexual and sexual reproduction Asexual - • fragmentation (breakage) of hyphae can produce new mycelium • production of spores by modified hyphae – spores and dispersed by wind Sexual - • always involves fusion of cells from different mating types (+/-) in some, the cells that fuse are gametes

5. There are four major groups of fungi Chytridiomycota Zygomycota Basidiomycota Ascomycota

6. Phylum Chytridiomycota – 1000 species aquatic, flagellated fungi – most closely related to ancestors of all fungi

7. Phylum Zygomycota – 1050 species Bread molds and relatives Sexual and asexual reproduction common

8. Phylum Basidiomycota – 22,000 speciesmushrooms, toadstools, rusts, smutsmany species eatenmany poisonous or semi-poisonous species

9. Phylum Ascomycota – 45,000 species –Most yeasts, truffles, morelsGreat diversity - includes many plant parasites –e.g. Dutch elm disease and chestnut blightSometimes called cup fungi because of the shapeof their reproductive structures

11. Yeasts – unicellular - most reproduction is asexual and takes place by cell fission or budding • ferment carbohydrates - produce ethanol as byproduct • play a leading role in genetic research

12. Which of the following is most closely related to a mushroom (fungus)? Why do you think so?

13. What do fungi “eat?” • Decomposers break down complex molecules into sugars or consume sugars found in environment • Examples: • common bread mold (eats carbs in bread) • shelf fungi on logs (eats carbs in cell wall of wood) • white button mushrooms in store (eats sugars and cellulose in dung)

14. What do fungi “eat?” • Symbiotic fungi receive their energy (carbohydrates) directly from a plant or algal partner Examples: • mycorrhizal fungi (live on plant roots) • lichens (contain algae)

15. What else do fungi “eat?” • Predatory fungi, catch and digest other organisms (like nematodes) But still absorptive nutrition! Just have to catch it first…

16. Summary: What do fungi eat? • Heterotrophs (cannot make their own food like plants) • Extracellular, absorptive nutrition secrete enzymes outside of their bodies, “digest” the food outside of their cells and then absorb the molecules into their cells. • Live in their substrate (food) How is this similar to us? What consequences/ advantages does it have?

17. Lichens

18. The white mushrooms comprise how many fungal individuals?

19. What is the same in these two photos? What does a fungus body look like?

20. Fungi are made of hyphae(cells joined in thread-like strands)

21. Mushrooms are for sexual reproduction (~flowers)Mycelium = body of the fungus Hyphae = the “bricks” from which the mushroom is built

22. Recap: Definition of fungus • Single or multi-celled eukaryote with heterotrophic,absorptive nutrition, chitinous cell walls, and which stores energy as glycogen • Live in food source or go dormant in low humidity

23. How big are fungi? • Microscopic (too small to see) • Small (can hold in your hand) • About as big as people • Larger than a house

24. Example of a “humungous fungus” • Armillaria bulbosa – a mushroom producing wood decomposer • Covers at least 38 acres in a forest in Michigan • Estimated to weigh 100 tons (size of a blue whale) • Estimated to be at least 1500 yrs old

25. Why should you care about fungi? A few reasons: • They make foods we like to eat • Mycorrhizae are responsible for plant life on land and high productivity rates • They decompose wood and organic matter • Penicillin and other medicines

26. Examples of foods made possible by fungi Yeast • Beer and Wine • Bread Mushrooms • White button, crimini,portabella • Truffles, chanterelles Mycoprotein (food additive like tofu) • Cheese • Rennin, • blue cheese • Soy sauce • Tempeh • Citric acid • (soft drinks)

27. Why should you care about fungi? A few reasons: • They make foods we like to eat • Mycorrhizae (plant:fungal symbioses that forms on plant roots) are responsible for plant life on land and high productivity rates • About 90% of all kinds of vascular plants are involved in mutualistic symbiotic relationships (mycorrhizae). • They decompose wood and organic matter • Penicillin and other medicines

28. Mycorrhizae • “myco” = fungus and “rhiza” = root • Symbiotic association between plant roots and fungi • Several different types of association (defined by structure of fungus:plant interface)

29. Advantages to fungi • Plants are a dependable and abundant source of carbohydrates

30. Advantages to plant • Fungi are better than plants at acquiring mineral nutrition (P,K, N) from the soil. • Fungi improve a plant’s access towater Because fungi • can access greater soil volume • can break molecules down into useable forms

31. Fungi can access more of the soil because • Hyphae are smaller than plant roots Root Hair Hyphae are 1/500th the diameter of a plant root hair hyphae

32. and fungi expand the surface area available for nutrient uptake

33. Fungi are better at acquiring nutrients because 2. Fungi have digestive enzymes that plants do not (remember absorptive nutrition) • Can turn inorganic phosphorus and nitrogen into forms usable by plants Because fungi secrete their enzymes outside of their cells (into the soil) they can use “dangerous” enzymes which produce too many free radicals to use inside cells

34. Recap of mycorrhizal benefits Fungi increase the water and nutrients available to their plant partners leading to: • Greater plant productivity (larger profits in the timber, fiber industries) • Greater reproductive success for plants(higher yields for agriculture) • Greater ecosystem stability Left: No mycorrhizal fungi Right: With mycorrhizal fungi

35. What would happen if a mycorrhizal fungus grew from one plant to another forming mycorrhizae with both?Hyphae are long “tubes” fungi are good at acquiring and moving compounds around.

36. These connections can form forest-wide networks!

37. Implication of fungal networks • If mycorrhizae can move significant amounts of carbon (sugar) between different plant species, this could reduce competition and contribute to the stability and diversity of ecosystems.

38. Inadvertent “Parenting” in fungi • Mycorrhizal connections also may move carbon from dominant trees to shaded seedlings (based on the same source sink relationship)

39. A range of mutualistic fungal-animal symbioses has been identified.• ruminants• leaf-cutter ants• termites

40. Why should you care about fungi? A few reasons: • They make foods we like to eat • Mycorrhizae are responsible for plant life on land and high productivity rates • They decompose wood and organic matter • Penicillin and other medicines

41. What would happen if wood was not decomposed?

42. Fungi are important decomposers! Fungi are the only organisms that can completely decompose lignin (what makes wood hard) Lignin must be broken down before any other decomposition can occur (no fungi = no decomposition by anyone). Fungi also decompose cellulose to glucose and play a major role in the global carbon cycle.

43. Why should you care about fungi? A few reasons: • They make foods we like to eat • Mycorrhizae are responsible for plant life on land and high productivity rates • They decompose wood and organic matter • Penicillin and other medicines • They’re just really cool!

44. Penicillium WWI, bacterial infections killed more soldiers than bullets. 1928 Dr. Andrew Fleming working at St. Mary’s Hospital in London noticed that mold growing on staph bacterial culture plates had killed the pathogen zone of dead bacteria

45. Penicillin kills bacteria by interfering with their ability to synthesize cell wall.

46. Why do fungi make antibiotics? Fungi produce antibiotics for the same reason we need them: to fight off bacterial infections

47. Why should you care about fungi? A few reasons: • They make foods we like to eat • Mycorrhizae are responsible for plant life on land and high productivity rates • They decompose wood and organic matter • Penicillin and other antibiotic