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Give an overview of Kingdom Fungi characteristics
- Heterotrophic extracellular digesters w/ unique enzymes (external digestion)
- Adapted for maximizing surface area (increased absorption)
- Many are Saprobes (eating rotten things)
- Multicellular (except yeast)
- Do not photosynthesize
- Cell walls are made of chitin (same as arthropods)
- Closer to animals than plants
- Most are filamentous in structure (hyphae)
- Can grow in wide range of conditions (eg jam, where bacteria can’t survive)
- Somatic cells are haploid
- Reproduce sexually and asexually
Describe ecological, disease, commercial, medicinal, and other aspects of Kingdom Fungi
- Ecological: diverse enzymes which have the ability to break down lignin, return important elements back to the soil, can decompose just about anything (paint, CDs, jet fuel, drywall mud, etc)
- Disease: 175 known to cause disease in humans. 5,000+ known to cause disease in plants.
- Commercial: growers spend $$$ on fungicides. Saccharomyces cerevisiae (brewer’s yeast) important for adult beverages, bread, and baking. Penicillium roqueforti involved in cheese production. Mushrooms eaten as food. Potential for toxic waste cleanup.
- Medicinal: original antibacterial (penicillin accidently discovered). Cyclosporine used as an immune suppressor during organ transplants.
- Other: yeasts are important for genetic research (metabolism, molecular genetics, eukaryotic development, etc)
Symbiotic association of kingdom Fungi?
- Mycorrhizae: 80% of vascular plants rely on mycorrhizae for N2 fixation
- Lichens: ½ fungi and ½ cyano or algae
Phyla of Kingdom Fungi + classes we need to know.
- Chytridiomycota, Zygomycota, Ascomycota, and Basidiomycota
- Basidiomycota -> Basidiomycetes, Teliomycetes, and Ustomycetes
- Basidiomycetes -> Hymenomycetes and Gastromycetes
Information about the hyphae of fungus, incl types
- Hyphae: branching threads of cells
- Mycelium: tangled mass of hyphae from a single fungus
- Aseptate (coencytic) hyphae filaments are like a giant interconnected cell (no walls between)
- Septate hyphae: individual cell separation can be seen
- Cytoplasm is shared between cells for yum-yum transfer and exchange
Give general kingdom Fungi reproduction information
- Produces non-moving spores asexually OR sexually
- Spores can be blown by the breeze, carried by insects, or propelled into the air mechanically
- Two types of asexual reproduction. Spores are produced by mitosis in both.
- Conidia: produced by conidiogenous hyphae (specialized cells that produce spores (conidia) that occur singly or in chains
- Sporangiospores: made within Sporangia which is attached to the sporangiophore (stalk-like structure).
- In sexual reproduction spores are made by mixing the genes from two parents, and involves meiosis.
- Sexually-produced spores are giving special names (ascospores, zygospores, basidiospores)
- Sexual reproduction always involves…
- Plasmogamy: fusion of cytoplasms leading to dikaryotic condition (can be long or brief)
- Karyogamy: fusion of nuclei, forming a diploid nucleus (very brief)
- Meiosos: immediate reduction of diploid nucleus to four genetically varied haploid nuclei
Zygomycota niches, hyphae, special types of hyphae
- Niches: Decomposers, parasites, endosymbionts (micorrhizae)
- Hyphae: Aseptate (coencytic) hyphae
- Specialized hyphae: stolons (horizontally connecting), sporangiophore (reproduction), rhizoid (anchorage), haustoria (parasitic)
Zygomycota sexual and asexual reproduction
- Asexual: sporangiospores are produced via mitosis in the sporangia, located at the top of the sporangiophore
- Sexual: Zygospores are produced via meiosis in the zygosporangia. Occurs when 2 compatible mating types are within range of eachother.
- Gametangia – gamete producing structures which spatially organize the haploid nuclei prior to karyogamy, and perform plasmogamy
- Mating type – genetically differentiated mating strains
Ascomycota types, hyphae
- Largest collection of species (30,000+)
- Types: Mold, powdery mildew (cause blights and rots), yeast, morels, truffles, parasites
- Hyphae: septate hyphae
Scientific names + info for truffles, yeast, and others listed in Ascomycota handout.
- Tuber melanosporum: (truffles) – highly prized in gourmet food industry. Worth up to $600/kg (2.2lbs). Collected with help of pig or dog (can smell) because truffles produce scent which is similar to female sex pheromone in pigs.
- Saccharomyces cerevisiae: (yeast) vast commercial and research applications
- Aspergillus niger: used to produce citric acid in sodas
- Aspergillus oryzae: used to make soy sauce/paste
- Caviceps purpurea: causes ergot in wheat/barley. Ergotized grain contains toxic chemicals including a precursor chemical to LSD. Consuming this grain can result in hallucinations, cramps, convulsions, and death.
- Chestnut blight: causes a disease known to have been responsible for killing at least 3.5 billion American chestnuts of the Eastern deciduous forests
- Penicillium: used to age cheese
- Dutch Elm Disease: causes death in elms, extremely virulent.
Ascomycota sexual and asexual reproduction
- Asexual: conidia (multinucleated) are formed via mitosis externally by conidiogenous cells which are at the tips of conidiophores (modified hyphae).
- Sexual: Asci form within the fruiting body known as an ascoma (or ascocarp). Both karyogamy and meisosis occur within the asci, producing 8 ascospores
- Ascoma can have 3 shapes: cleistothecium (complete enclosed), perithecium (small pore at top), or apothecium (cup shaped)
- Asci usually develop on an inner surface of the ascoma called the hymenial layer.
Basidiomycota types, hyphae
- Very diverse phylum, 22,000+ species
- Basidiomycetes – Hymenomycetes: Mushrooms, coral fungi, tooth fungi, shelf fungi
- Basidiomycetes – Gastromycetes: Puffballs earthstars, stinkhorns, false puffballs, bird’s nest fungi
- Teliomycetes: rusts – bright colors
- Ustomycetes: smuts – look like ash
- Hyphae: Septate hyphae that include parenthosomes around each perforation
Basidiomycota sexual reproduction
- Lack unique asexual structures, so sexual is the focus
- For class Basidiomycetes…
- 1. Haploid basidiospores germinate and form monokaryotic mycelium
- 2. Different mating types undergo plasmogamy and create a dikaryotic mycelium
- 3. Regions of the dikaryotic mycelium enlarge and form a basidiomata (usually in response to light and low CO2)
- 4. Karyogamy occurs withing basidia (found inside gill of basidiomata), creating diploid zygote
- 5. Basidiospores (connected to basidium by sterigma) are formed AFTER meosis occurs
- For classes Teliomycetes and Ustomycetes…
- No basidioma, spores are produced in masses called sori (singular sorus)
- Still form basidia and basidiospores.
- Class Teliomycetes have incredibly complex life cycles with multiple hosts (eg Puccina graminis)
- Class Ustomycetes produce dusty masses of teliospores. Typically produce large swelling due to internal mycelium growth. Only need on host in their life cycles.
Describe class Basidiomycetes
- Hymenomycetes: have distinct fertile layer (hymenial layer) where basidiospores are produced. This layer is exposed to the environment BEFORE the spores mature.
- Psiocybe mexicana is structurally similar to LSD, used in religious ceremonies. Prior to 1960s studies showed LSD may help personality disorders.
- Gastromycetes: No distinguishable hymenial layer. Basidioma have distinct outer periderm which causes INTERNAL spore maturation. This layer either ruptures or opens naturally once the basidiospores are mature.
General information about yeasts
- Single celled fungus
- Primary mode of reproduction is budding, can sexual reproduce (ascospores)
- Most are Ascomyecetes
- Used for bread, alcohol, baking, and genetic research
Information about Conidial fungi + commercial importance
- Used to be called Deuteromycetes
- Grab-bag of ~15,000 species
- Sexual lifecycle is absent or unknown. However some members are known, but classified into this category based on strong similarities with other members.
- Aspergillus – helps produce soy sauce
- Penicillium roqueforti – helps create many cheeses (Danish blue, Gorgonzola, Stilton)
Information about Lichens (a lot)
- ½ fungi (usually ascomycetes) and ½ cyano or algae
- Capable of both photosynthesis and decomposition.
- Able to live in extremely varied environments
- Reproduction by simple fragmentation and soredia (algal cells + fungal cells already) dispersal
- Key to longevity is suspended animation which occurs when they are dry
- Important aspects…
- Ecological pioneers – set up environment for other organisms
- Lichens containing cyanobacteria may help with N2 fixation
- Great pollution indicators because they cannot excrete chemicals that they absorb from their surroundings. Extensively used to monitor toxic air pollutants such as sulfur dioxide
- Three types…
- Crustose: flat/crusty
- Foliose: leaflike
- Fruticose: tall and shrublike
Information about Mycorrhizae
- Benefit plant by increasing absorption of phosphorus, zinc, manganese, and copper
- Fungi benefit by receives carbohydrates and vitamins from the host
- Endomycorrhizae: penetrate root cells. Hyphae penetrate root tissue cells forming highly branched structures called arbuscules and occasionally swellings called vesicles.
- Arbuscules – associate w/ plasma membranes and are thought to aid transfer of materials between environment and cells by increasing surface area
- Ectomycorrhizae: surround the roots. A highly branched network of hyphae (Hartig Net) forms around the root epidermal and cortex cells.