Kingdom Fungi

1. Kingdom Fungi • The characteristics of fungi • The evolution of the fungi • Fungal classification • Fungal life cycles • Human-Fungus Interactions

2. The Characteristics of Fungi • Body form • unicellular (yeasts) • filamentous (tube-like strands called hypha (singular) or hyphae (plural) • mycelium = aggregate of hyphae • Some fungi are dimorphic! Multicellular • sclerotium = hardened mass of mycelium that generally serves as an overwintering stage. • multicellular, such as mycelial cords, rhizomorphs, and fruit bodies (mushrooms)

3. The Characteristics of Fungi • Heterotrophy - 'other food' • Saprophytes or saprobes - feed on dead tissues or organic waste (decomposers) • Symbionts - mutually beneficial relationship between a fungus and another organism • Parasites - feeding on living tissue of a host.  • Parasites that cause disease are called pathogens.

4. Heterotrophic by Absorption • Fungi get carbon from organic sources • Hyphal tips release enzymes • Enzymatic breakdown of substrate • Products diffuse back into hyphae Products Enzymatic breakdown Nucleus hangs back and “directs” Enzymes Product diffuses back into hypha and is used

5. Tubular Hard wall of chitin Crosswalls may form compartments (± cells) Multinucleate Grow at tips Hyphae

6. Hyphal growth • Hyphae grow from their tips • Mycelium = extensive, feeding web of hyphae • Mycelia are the ecologically active bodies of fungi This wall is rigid Only the tip wall is plastic and stretches

7. Modifications of hyphae

8. Fungi as Saprobes and Decomposers

9. Fungi as Symbionts (Mutualism)

10. Mycorrhizae • “Fungus roots” • Mutualism between: • Fungus (nutrient & water uptake for plant) • Plant (carbohydrate for fungus) • Several kinds • Zygomycota – hyphae invade root cells • Ascomycota & Basidiomycota – hyphae invade root but don’t penetrate cells • Extremely important ecological role of fungi!

11. “Ecto”mycorrhizae Russula mushroom mycorrhizas on Western Hemlock root Mycorrhiza cross sections Fungal hyphae around root and between cells

12. Lichens • “Mutualism” between • Fungus – structure • Alga or cyanobacterium – provides food • Three main types of lichens: • Crustose lichens form flat crusty plates.  • Foliose lichens are leafy in appearance, although lobed or branched structures are not true leaves. • Fruticose lichens are even more finely branched and may hang down like beards from branches or grow up from the ground like tiny shrubs.

13. Lichen internal structure • Lichens are nature’s biological monitors of pollution and air quality • Thalli act like sponges • Some species more sensitive to pollution • Which species are present can indicate air quality • Most resistant species can also be analyzed for pollutants, including bioaccumulation of heavy metals and radioactive isotopes Lobaria

14. Fungi as Parasites & Pathogens

15. Fungi are Spore-ific!!! • Spores - asexual (product of mitosis) or sexual (product of meiosis) in origin. • Purpose of Spores • Allows the fungus to move to new food source. • Resistant stage - allows fungus to survive periods of adversity. • Means of introducing new genetic combinations into a population

16. Reproduce by spores • Spores are reproductive cells • Sexual (meiotic in origin) • Asexual (mitotic in origin) • Formed: • Directly on hyphae • Inside sporangia • Fruiting bodies Penicillium hyphae with conidia Pilobolus sporangia Amanita fruiting body

17. Mycelia have a huge surface area Hyphal growth from spore germinating spore mycelium

18. The Characteristics of Fungi • Fungus is often hidden from view. It grows through its food source (substratum), excretes extracellular digestive enzymes, and absorbs dissolved food. • Indeterminate clonal growth. • Vegetative phase of fungus is generally sedentary.

19. The Characteristics of Fungi • Cell wall present, composed of cellulose and/or chitin. • Food storage - generally in the form of lipids and glycogen. • Eukaryotes - true nucleus and other organelles present. • All fungi require water and oxygen (no obligate anaerobes). • Fungi grow in almost every habitat imaginable, as long as there is some type of organic matter present and the environment is not too extreme. • Diverse group, number of described species is somewhere between 69,000 to 100,000 (estimated 1.5 million species total).

20. Generalized Life Cycle of a Fungus

21. Evolution of the fungi

22. asci basidia zygosporangia Classification & Phylogeny motile spores

23. Chytridiomycota – “chytrids” • Simple fungi • Produce motile spores - zoospores • Mostly saprobes and parasites in aquatic habitats • Could just as well be Protists Chytridium growing on spores Chytriomyces growing on pine pollen

24. Zygomycota – “zygote fungi” Rhizopus on strawberries • Sexual Reproduction - zygosporangia • Asexual reprod. – common (sporangia – bags of asexual spores) • Hyphae have no cross walls • Grow rapidly • Decomposers, pathogens, and some form mycorrhizal associations with plants Rhinocerebral zygomycosis

25. Sexual zygsporangium with one zygospore Asexual sporangium with spores inside Life cycle of Rhizopus

26. Ascomycota – “sac fungi” • Sexual Reproduction – asci (sing. = ascus) • Asex. Reprod. – common • Cup fungi, morels, truffles • Important plant parasites & saprobes • Yeast - Saccharomyces • Decomposers, pathogens, and found in most lichens A cluster of asci with spores inside

27. Sac fungi diversity

28. Basidiomycota – “club fungi” • Sexual Reproduction – basidia • Asexual reprod – not so common • Long-lived dikaryotic mycelia • Rusts & smuts –plant parasites • Mushrooms, polypores, puffballs, boletes, bird’s nest fungi • Enzymes decompose wood, leaves, and other organic materials • Decomposers, pathogens, and some form mycorrhizal associations with plants SEM of basidia and spores

29. mycelium and fruiting body are dikaryotic Mushroom Life Cycle haploid mycelium Hyphal fusion of haploid mycelia N 2N N+N Meiosis Nuclear fusion in basidium young basidia - the only diploid cells

30. Bioluminescence in Mycena

31. Some fungi have more than one scientific name – Why? • Teleomorph: the sexual reproductive stage (morph), typically a fruiting body (e.g., Morchella esculenta, Agaricus brunescens). • Anamorph: an asexual reproductive stage (morph), often mold-like (e.g. Aspergillus flavus, Fusarium solani). When a single fungus produces multiple morphologically distinct anamorphs, they are called synanamorphs. • Holomorph: the whole fungus, including all anamorphs and the teleomorph.

32. Deuteromycota – Form Phylum “Imperfect Fungi” • Fungi that seldom or never reproduce sexually. • Asexual reproduction by vegetative growth and production of asexual spores common.

33. Yeasts • Single celled fungi • Adapted to liquids • Plant saps • Water films • Moist animal tissues Candida Saccharomyces

34. Molds • Rapidly growth • Asexual spores • Many human importances • Food spoilage • Food products • Antibiotics, etc. Noble Rot - Botrytis Antibiotic activity

35. HUMAN-FUNGUS INTERACTIONS • Beneficial Effects of Fungi • Decomposition - nutrient and carbon recycling. • Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms). • Model organisms for biochemical and genetic studies. • Harmful Effects of Fungi • Destruction of food, lumber, paper, and cloth. • Animal and human diseases, including allergies. • Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.). • Plant diseases.

36. Fungi Classification of fungal diseases (mycoses) Superficial, cutaneous, subcutaneous Systemic and opportunistic Poisoning and allergies Treatment Azole drugs, amphotericin B, others

37. Cutaneous and subcutaneous Dermatophytes: various genera Cause skin and nail diseases Referred to as tinea (worm) because of the ring-like appearance on scalp and skin. Cause ringworm, jock itch, athlete’s foot, etc. Limited to outer layer of skin Sporothrix schenkii Acquired from soil and plant material Infects deeper into skin, but not systemic

38. Systemic Mycoses Generally acquired by inhalation of spores Lung infections, may spread beyond into other tissues Blastomyces (blastomycosis) Coccidiodes (coccidiomycosis) Histoplasma (histoplasmosis) Most common in this area (Ohio and Miss. River valleys) Soil contaminated with bird or bat droppings Many people exposed with asymptomatic cases Many test positive for exposure

39. Opportunistic infections Aspergillus (aspergillosis) Variety of species, very common in soil, plant materials Serious infections in immunocompromised Allergies to A. fumigatus Poisoning from aflatoxin from A. flavus Candida (candidiasis)- normal microbiota Cause of vaginal infections, diaper rash, thrush Capable of infecting any part of the body Dangerous in cancer patients, HIV infections, etc.

40. Opportunists-2 Cryptococcus neoformans Inhalation of spores Can infect many parts, but has predilection for CNS Particularly serious in AIDS Pneumocystis carinii Very protozoan like, but is a fungus Most cases associated with AIDS Serious lung infections: PCP (P. carinii pneumonia)

41. Fusarium ATLANTA, Aug. 23 -- Minus a smoking gun, CDC researchers have nonetheless indicted a contact lens solution that was removed from the market earlier this year in the wake of a widespread outbreak of Fusarium keratitis. Contact lens wearers should not use ReNu with MoistureLoc, made by Bausch & Lomb of Rochester, N.Y., said Douglas Chang, M.D., of the CDC here, and colleagues. http://www.medpagetoday.com/Ophthalmology/GeneralOphthalmology/tb/3980