Fungi Unit 8- Chapter 31

What is a Fungi? Usually multicellular Usually multicellular Above ground structures (mushrooms) Above ground structures (mushrooms) Breakdown organic material and recycle nutrients Breakdown organic material and recycle nutrients Tiny fraction causes disease Tiny fraction causes disease Plant roots depend on them to help with nutrient absorbtion (symbiotic relationship) Plant roots depend on them to help with nutrient absorbtion (symbiotic relationship)

Nutrition and Lifestyle Heterotrophs Heterotrophs Do not ingest food Do not ingest food Secrete enzymes (exoenzymes) into their surroundings, which break down complex molecules for the fungi to absorb. Secrete enzymes (exoenzymes) into their surroundings, which break down complex molecules for the fungi to absorb. Some species are: Some species are: Decomposers: break down non living material (logs, wastes from animals, animal corpses Decomposers: break down non living material (logs, wastes from animals, animal corpses Parasites: absorb nutrients from host cells Parasites: absorb nutrients from host cells Mutualistic symbionts: absorb nutrients from host cell but the host cell isn’t hurt but rather benefits from the fungi Mutualistic symbionts: absorb nutrients from host cell but the host cell isn’t hurt but rather benefits from the fungi

Body Structure Single cell fungi = yeast Single cell fungi = yeast Most are multicellular Most are multicellular Hyphae: A filament that collectively makes up the body of a fungus. Hyphae: A filament that collectively makes up the body of a fungus. Chitin: a strong but flexible polysaccharide that makes up the cell wall of fungi. Chitin: a strong but flexible polysaccharide that makes up the cell wall of fungi. Mycelium: the branched network of hyphae that allows for feeding Mycelium: the branched network of hyphae that allows for feeding

Specialized Hyphae Septa: pores large enough for organelles to flow from cell to cell Septa: pores large enough for organelles to flow from cell to cell Coenocytic: lack pores, continuous cytoplasm with many nuclei. Coenocytic: lack pores, continuous cytoplasm with many nuclei. Haustoria: enables penetrating of a host cells tissue. Mycorrhizae: symbiotic relationship with plant roots.

Sexual Reproduction Hyphae from 2 different mycelia release sexual signaling molecules (pheromones) Hyphae from 2 different mycelia release sexual signaling molecules (pheromones) Both Hyphae extend toward the source of pheromones and fuse together. Both Hyphae extend toward the source of pheromones and fuse together. “Compatibility Test” prevents haphae from fusing with hyphae from the same mycelium. “Compatibility Test” prevents haphae from fusing with hyphae from the same mycelium. Union of cytoplasm (plasmogamy) Union of cytoplasm (plasmogamy) Hours, days, centuries later the haploid nuclei from each parent fuse together = diploid cell (karyogamy) Hours, days, centuries later the haploid nuclei from each parent fuse together = diploid cell (karyogamy) Meiosis occurs and restores cells back to haploid form producing spores Meiosis occurs and restores cells back to haploid form producing spores

Asexual Reproduction Clones are produced by mitotic production of spores Clones are produced by mitotic production of spores Spores are spread through air, wind, water Spores are spread through air, wind, water Molds (kitchen products) produce spores Molds (kitchen products) produce spores Yeast (moist habitats) simple cell division Yeast (moist habitats) simple cell division

Fungal Phylogeny

Phylum Chytridiomycota Aka Chytrids Aka Chytrids Earliest of all fungi Earliest of all fungi Unique flagellated spores (zoospores) Unique flagellated spores (zoospores) Either decomposers or parasites Either decomposers or parasites

Phylum Zygomycetes Fast growing molds Fast growing molds Aka Zygote Fungi Aka Zygote Fungi Some are parasites or commensal symbionts (one benefits) Some are parasites or commensal symbionts (one benefits) Coenocytic hyphae Coenocytic hyphae Parasites = Mycrosporidia Parasites = Mycrosporidia

Phylum Glomeromycota Glomeromycetes Glomeromycetes Form endomycorrhizae with plant roots Form endomycorrhizae with plant roots Hyphae branch into treelike structures Hyphae branch into treelike structures

Phylum Ascomycetes Production of sexual spores (asci) Production of sexual spores (asci) Aka Sac Fungi Aka Sac Fungi Fruit bodies (ascocarps) Fruit bodies (ascocarps) Decomposers of plants Decomposers of plants Symbiotic relationships with plant roots and green algae (lichen) Symbiotic relationships with plant roots and green algae (lichen) Asexual reproduction: Produce asexual spores (conidia) where the spores are released into the wind and attach to a hyphae Asexual reproduction: Produce asexual spores (conidia) where the spores are released into the wind and attach to a hyphae Sexual reproduction: Fusion of 2 different mating types, asci produces ascospores which are later released by ascocarp. Sexual reproduction: Fusion of 2 different mating types, asci produces ascospores which are later released by ascocarp.

Phylum Basidiomycota Basidiomycetes Basidiomycetes Mushrooms, shelf fungi, aka club fungi Mushrooms, shelf fungi, aka club fungi Some molds and parasites (rust and smuts) Some molds and parasites (rust and smuts) Decomposers of wood and plant material Decomposers of wood and plant material Sexual reproduction Sexual reproduction Fruiting bodies (basidiocarps) ex: mushroom Fruiting bodies (basidiocarps) ex: mushroom Mushroom cap releases the basidiospores Mushroom cap releases the basidiospores Asexual reproduction is less common Asexual reproduction is less common

Impact of Fungi Decomposers: - Plants (cellulose) - Keep ecosystems stocked with inorganic nutrients - Balance carbon, nitrogen, and other essential elements - recycle Symbionts: 1. Mycorrhizae- relationship with plant roots - Helps absorb nutrients that root couldn’t normally get on its own. 2. Fungus/Animal Symbiosis-break down plant material in the guts of animals. -Ants take leaves to fungi so they can break it down to a material in which the ants can digest. 3. Lichens- surface hugging carpet found growing on rocks, trees, roofs, etc. -fungi + green algae or cyanobacteria -”dual organism” -sensitive to air pollution Pathogens: -About 30% (mostly in plants) -Affect agriculture -When infected in animal/humans (mycosis) -Ringworm -Athletes foot -Black mold

Practical use of Fungi Mushroom for food Mushroom for food Fungi is used to ripen some cheeses Fungi is used to ripen some cheeses Fungi are used to produce citric acid in soft drinks Fungi are used to produce citric acid in soft drinks Yeast are used for alcoholic beverages Yeast are used for alcoholic beverages Antibiotics for bacterial infections (penicillin) Antibiotics for bacterial infections (penicillin) Medical research Medical research