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55 Cards in this Set
- Front
- Back
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Hyphae |
-each of the branching filaments that make up the mycelium of a fungus. -Apically elongating,branching cylindrical filamen |
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HYPHAL GROWTH |
•Spitzenkörper – structure unique to fungi -Present at hyphal tip or point of branch initiation -Vesicles contain building blocks of cell wall |
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Mycelium |
–mass of hyphae –vegetative stage –in or on substrate |
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Eumycota |
true fungi Cell wall - chitin fibres in glucan matrix Nutrition absorptive (not phagotrophic) No chloroplasts Mitochondrial cristae flattened Flagellae (when present) Lysine biosynthesis AAA |
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fungoid CHROMISTA |
Oomycetes (water moulds) Labyrinthulids (slime nets) |
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fungoid PROTOZOA |
•Slime moulds (Myxomycota) •Plasmodium - multinucleate, often motile •Digestion phagotrophic (engulf food such as bacteria) •Reproduce by spores |
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Eumycota |
Phyla - distinguished by sexual spore production Ascomycota • Basidiomycota • Chytridiomycota (flagellate zoospores) • Zygomycota (zygospores) |
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ZYGOMYCOTA |
-Zygospores from fusion of two gametangia -Asexual spores in sporangia • Examples Pin mould (Rhizopus) |
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CHYTRIDIOMYCOTa |
•Globular thallus with rhizoids • Flagellate spores (single flagellum) Batrachochytrium (frog disease) |
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BASIDIOMYCOTA |
-spores produced on basidia -Usually four spores (each with a single nucleus) -clamp connections at septum Examples • Mushrooms • Coral Fungi |
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ASCOMYCOTA |
-ascospores produced inside asci -Anamorphs are frequent -Lichenisation occurs in several groups -Huge diversity e.g. Morels (Morchella) •Disc fungi• Penicillium (anamorph) |
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Basidiomycota life cycle |
•Spore is haploid, germinates to form monokaryon •Compatible monokaryons fuse to form dikaryon (two separate nuclei) • Extended dikaryotic phase and very brief diploid stage (in the basidium) just prior to meiosis plasmogamy and karogamy are separate |
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Plasmogamy |
fusion of cytoplasm |
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karyogamy |
fusion of nuclei |
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Basidomycota sex |
•Sexual compatibility controlled by mating type genes, with no sexual differentiation •Mating type genes: one locus (bipolar or unifactorial) or two locus (tetrapolar or bifactorial) Two to numerous mating type factors at each mating type locus •Compatible mating when mating type factors of two monkaryons are different •Mix of outbreeding and inbreeding possible |
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Basidomycota Three subphyla: APU |
Agaricomycetes Spores produced in hymenium (layer of basidia) or as gleba (mass) e.g. agarics, boletes |
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Agarics |
•Macrofungi with lamellae (gills) •Spores produced in hymenium: layer of basidia and sterile elements •Also called mushrooms (edible) or toadstools (the rest) •Occur in Agaricales, and other orders |
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Gleba |
randomly arranged’ hymenium) initially enclosed within one to several layered peridium -solid mass of spores |
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PHALLALES: Stinkhorns |
•Gleba slimy • Fruit body initially within ‘egg’ (peridium) • spore bearing tissue on receptacle • Receptacle often brightly coloured, bizarre shapes |
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HYMENIUM |
Hymenium is layer of basidia, that produce spores •Sometimes with sterile elements (cystidia) |
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SPORE RELEASE |
At microscopic level, spores usually shot off forcibly from basidia -Spores fall in ‘sporabola’ -Horizontal portion of sporabola determines distance between lamellae or width of |
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SPORE DISPERSAL: PASSIVE |
•Agarics and other fungi with hymenium - spores fall downwards (as seen in spore print) and are wind dispersed •Pileus often raised above substrate by a stipe. Pileus protects hymenium from rain (otherwise lamellae stick together) and stipe raises hymenium into air currents •Puffballs - rain drops fall on peridium, which pushes inwards producing puff of spores through stoma •Birds-nest fungi - raindrops splash peridioles out of ‘nest’ |
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SPORE DISPERSAL: ACTIVE |
Stinkhorns: flies attracted to stinking slimy gleba (spore mass) on receptacle that can mimic rotten mea |
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SPORE DISPERSAL: ACTIVE |
•Hypogeal (underground) fruit-bodies eaten by mammals •Spores germinate after passage through gut (allows mixing of spores from genetically different fungal individuals) •Hypogeal fruit-bodies strongly scented (sex pheromones emitted by truffles, attractive to pigs) •Passive dispersal may occur after active dispersal (especially where powdery spore |
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Convergent evolution of fruitbody forms: FALSE TRUFFLES |
Hymenium enclosed, structurally labyrinthine or ‘lamelloid’ •Spores not actively discharged (microscopically) •Spores break off from basidium rather than being shot off •No spore print produced •Spores occasionally powdery or slimy •Stipe absent or reduced |
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ASCOMYCOTA |
•Sexual spores are ascospores, produced in interior of asci •Usually eight spores (each with a single nucleus) or multiples of eight spores •Septate hyphae, without clamp connections |
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Ascomycota: septa |
•No clamp connection at septum •Septum with a central pore surrounded by Woronin bodies •Woronin bodies are vesicles with a dense central core, role is sealing septal pores after damage to hyphae |
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ASCOMYCOTA LIFE CYCle |
•Ascogonium and antheridium •Dikaryon (two separate nuclei, one from each parental monokaryon) •Diploid nucleus formed in young ascus •Meiosis produces four haploid spores in ascus •Post meiotic mitosis doubles spores to eight (or more, with further mitotic divisions) |
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Asci |
•Unitunicate – one wall -Operculate (apical ‘lid’) -Inoperculate |
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BITUNICATE ASCUS |
•Two walls •Thick, elastic inner layer (endotunica) •Thin, rigid outer layer (ectotunica) •Ascospore release by extension of the inner endotunica, and rupture of outer ectotunica (like ‘jack-in-the-box’) |
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Prototunicate – |
no opening, walls break down |
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Ascocarp CAPP |
is the fruiting body (sporocarp) of an ascomycete phylum fungus. |
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ASCOCARP: CLEISTOTHECIUM |
•Asci enclosed in thick-walled, globose ascocarp •Exterior may have appendages •Eventually ruptures or stroma is dispersal by animals •Can be resting |
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ASCOCARP: PERITHECIUM |
•Asci enclosed in flask-shaped ascocarp •Apical opening (ostiole), at top of neck •Asci formed in hymenium at base of flask |
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ASCOCARP: PERITHECIUM |
small fruiting bodies can be produced individually, directly on the substrate, or numerous perithecia can be embedded in a stroma |
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ASCOCARP: APOTHECIUM |
•Asci formed in disc or cup-shaped ascocarp •Asci in hymenium, exposed on upper surface of disc or cup |
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FOSSIL ASCOMYCOTA |
•Paleopyrenomycitesdevonicus •Early Devonian - 400 million year old Rhynie chert •Perithecia, with asci and ascospores •Growing within tissue of the vascular plant Asteroxylon. |
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ASEXUAL SPORES |
•Asexual spores (also called mitospores) very common among Ascomycota •Forms producing asexual spores originally classified among other fungi, on basis of fruit-body •Tulasne brothers (1861) made connection between asexual and sexual stages of the same fungus (pleomorphism – different forms of the one fungus) |
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Holomorph Teleomorph Anamorph Synanamorphs |
Holomorph - the whole fungus (all stages) •Teleomorph - stage producing sexual spores (= perfect stage) •Anamorph - stage producing asexual spores (= imperfect stage) •Synanamorphs - two or more anamorphic species which have the same teleomorph |
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Lichens |
a mutualistic relationship between a fungus and an alga or a cyanobacterium
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mycobiont |
fungal partner Most (98%) lichens involve fungi from the Ascomycota, determines name |
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photobiont |
algal and/or cyanobacterial partner Most (90%) photobionts are green algae Photobionts may also be free-living |
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Lichen classification |
•The body of a lichen=thallus •Hyphae of upper surface form a cortex •The internal medulla is composed of loosely interwoven hyphae •Layer of photobiont, usually below cortex |
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crustose |
flat, paint-like, adhering to substrate (no lower cortex) |
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foliose |
flat and leaf-like, but not closely adhering to the surface with upper and lower cortex |
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fruticose |
erect and often branched so as to appear ‘bushy’ or ‘shrub-like' |
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Rhizines |
are attachment organs on the underside of thallus of foliose lichens |
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Soredia |
-asexual propagates -photobiont cells enveloped by mantle of fungal hyphae •Soredia are dispersed across the thallus, or in soralia |
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Isidia |
outgrowths of the cortex -Asexual -Fragile – can break off and disperse -Also increase area for photosynthesis and gas exchange |
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•Sexual spores |
are produced in exactly the same way as in non-lichenised fungi •Lichenised Ascomycota have asci in apothecia or perithecia |
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Lichen Mutualism |
mycobiont gains carbohydrates from photosynthesis photobiont gains nutrients; the mycobiont also provides protection for the photobiont |
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Lichens tough |
-the relationship allows lichens to grow in harsh environments such as exposed rock surfaces, deserts and polar regions -lichens survive in tough conditions by rapidly drying out; thallus often only 2-10% water •on drying, photosynthesis ceases and other activity slows •lichens very efficient accumulators of minerals, extremely sensitive to pollutants |
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Secondary metabolites |
lichens produce numerous secondary metabolites (non-essential pathways) •made by the fungal component, deposited on surface of hyphae •some metabolites screen light •‘lichen acids’ involved in weathering of rock •metabolites are useful in taxonomy |
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Foliicolous lichens |
-Lichens that grow on leaves – some are obligate •Diverse in tropical rainforests and also some in temperate rainforests •May live on or under the cuticle, but not parasitic |
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Lichenicolous fungi |
•Non-lichenised fungi that grow on lichens •At least 1,000 species •Often inconspicuous •Mild to severe parasites |
