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The FungiChapter 23
The FungiThe Fungi 2
OutlineOutline
CharacteristicsCharacteristicsStructureStructureReproductionReproduction
EvolutionEvolutionSac FungiSac FungiYeastsYeastsClub FungiClub FungiSmuts and RustsSmuts and Rusts Imperfect FungiImperfect Fungi
Symbiotic RelationshipsSymbiotic Relationships
The FungiThe Fungi 3
Characteristics of the FungiCharacteristics of the Fungi
Kingdom Fungi contains 80,000 sppKingdom Fungi contains 80,000 spp
Mostly multicellular eukaryotes that Mostly multicellular eukaryotes that share a common mode of nutritionshare a common mode of nutrition
HeterotrophicHeterotrophic
Cells release digestive enzymes and Cells release digestive enzymes and then absorb resultant nutrient then absorb resultant nutrient moleculesmolecules
Some are parasiticSome are parasitic
Several have mutualistic relationshipSeveral have mutualistic relationship
The FungiThe Fungi 4
Structure of FungiStructure of Fungi
Body (thallus) of most fungi is multicellular Body (thallus) of most fungi is multicellular mycelium (yeasts are unicellular)mycelium (yeasts are unicellular)Consists of a vast network of thread-like Consists of a vast network of thread-like hyphaehyphaeSeptate fungi have hyphae with cross wallsSeptate fungi have hyphae with cross wallsNonseptate fungi are multinucleatedNonseptate fungi are multinucleatedHyphae grow from tipHyphae grow from tip
Give the mycelium a large surface area per Give the mycelium a large surface area per unit volumeunit volume
Cell walls of chitin, like insect exoskeletonCell walls of chitin, like insect exoskeletonExcess food stored as glycogen as in animalsExcess food stored as glycogen as in animalsPossibly evolved from red algae - both lack Possibly evolved from red algae - both lack flagellaflagella
5Mycelia and Hyphae of Fungi
The FungiThe Fungi 6
Reproduction of FungiReproduction of Fungi
Both sexual (in most) and asexual Both sexual (in most) and asexual reproductionreproduction
Sexual reproduction involves three Sexual reproduction involves three stages:stages:
Haploid HyphaeHaploid Hyphae
Dikaryotic StageDikaryotic Stage
Diploid ZygoteDiploid Zygote
The FungiThe Fungi 7
Reproduction of FungiReproduction of Fungi
During sexual reproduction, hyphae from During sexual reproduction, hyphae from two different mating types fusetwo different mating types fuse
Hyphae that contain paired haploid nuclei Hyphae that contain paired haploid nuclei are said to be dikaryoticare said to be dikaryotic
Nuclear fusion produces diploid nucleus, Nuclear fusion produces diploid nucleus, which produces haploid windblown spores which produces haploid windblown spores by meiosisby meiosis
Spores germinate directly into haploid Spores germinate directly into haploid hyphae without embryological developmenthyphae without embryological development
Asexual reproduction usually involves the Asexual reproduction usually involves the production of windblown sporesproduction of windblown spores
Unicellular yeasts reproduce by buddingUnicellular yeasts reproduce by budding
8Dispersal of Spores
The FungiThe Fungi 9Diversity of Fungi:Diversity of Fungi:ZygomycotaZygomycota
Zygospore FungiZygospore Fungi
Phylum ZygomycotaPhylum Zygomycota
Mainly saprotrophs decomposing Mainly saprotrophs decomposing animal and plant remainsanimal and plant remains
Black bread mold - Black bread mold - Rhizopus Rhizopus stoloniferstolonifer
10Black Bread Mold,
Rhizopus stolonifer
The FungiThe Fungi 11Diversity of Fungi:Diversity of Fungi:ZygomycotaZygomycota
Life cycleLife cycle Hyphae of opposite mating types grow toward Hyphae of opposite mating types grow toward each othereach other
Hyphae swell at tips; cross walls develop behind Hyphae swell at tips; cross walls develop behind each end; form gametangiaeach end; form gametangia
Gametangia merge resulting in a large multi-Gametangia merge resulting in a large multi-nucleate cellnucleate cell
Nuclei of the two mating types pair and then fuseNuclei of the two mating types pair and then fuse
A thick wall develops around the zygosporeA thick wall develops around the zygospore
The zygospore becomes dormant for periodThe zygospore becomes dormant for period
Sporangiophore(s) then sporangia develop, Sporangiophore(s) then sporangia develop, spores releasedspores released
Spores dispersed by air currents; germinate into Spores dispersed by air currents; germinate into myceliamycelia
The FungiThe Fungi 12Diversity of Fungi:Diversity of Fungi:Sac FungiSac Fungi
Phylum Ascomycota - about 60,000 species of sac Phylum Ascomycota - about 60,000 species of sac fungifungi
Most are saprotrophs that digest resistant Most are saprotrophs that digest resistant materials containing cellulose, lignin, or collagenmaterials containing cellulose, lignin, or collagen
Most are composed of septate hyphaeMost are composed of septate hyphaeNeurosporaNeurospora, experimental organism for the one-, experimental organism for the one-gene-one-enzyme studiesgene-one-enzyme studies
Morels and truffles, famous gourmet delicacies Morels and truffles, famous gourmet delicacies revered throughout the worldrevered throughout the world
Many plant diseases: Powdery mildews; leaf curl Many plant diseases: Powdery mildews; leaf curl fungi; ergot of rye; chestnut blight and Dutch elm fungi; ergot of rye; chestnut blight and Dutch elm diseasedisease
AspergillusAspergillus and and CandidaCandida cause serious human cause serious human infectionsinfections
TalaromycesTalaromyces (formerly (formerly PenicilliumPenicillium) is source of ) is source of penicillinpenicillin
The FungiThe Fungi 13Sac Fungi:Sac Fungi:Reproduction - Asexual Reproduction - Asexual
Life cycleLife cycleAsexual reproduction is the normAsexual reproduction is the norm
Yeasts usually reproduce by buddingYeasts usually reproduce by budding A small bulge forms on side of cell A small bulge forms on side of cell Receives a nucleus and gets pinched off and Receives a nucleus and gets pinched off and becomes full sizebecomes full size
The other ascomycetes produce spores called The other ascomycetes produce spores called conidia or conidiosporesconidia or conidiospores
Vary in size and shape and may be multicellularVary in size and shape and may be multicellular Conidia usually develop at the tips of conidiophores Conidia usually develop at the tips of conidiophores
Conidiophores differ in appearance and are Conidiophores differ in appearance and are diagnosticdiagnostic
Conidia are windblownConidia are windblown Conidia of Conidia of CladosporiumCladosporium cause allergies - cause allergies - concentrations of more than 35,000 conidia/mconcentrations of more than 35,000 conidia/m33 over Leiden (Germany)over Leiden (Germany)
14Asexual Reproduction in Sac Fungi
The FungiThe Fungi 15Sac Fungi:Sac Fungi:Reproduction - SexualReproduction - Sexual
Life cycle, cont.Life cycle, cont.
Sexual reproductionSexual reproductionAscus refers to the fingerlike sac that Ascus refers to the fingerlike sac that develops during sexual reproductiondevelops during sexual reproduction
Asci usually surrounded and protected by Asci usually surrounded and protected by sterile hyphae within an ascocarpsterile hyphae within an ascocarp In cup fungi, ascocarps are cup-shapedIn cup fungi, ascocarps are cup-shaped In morels they are stalked and are pitted In morels they are stalked and are pitted like the surface of the moonlike the surface of the moon
Haploid hyphae fuse to make diploid Haploid hyphae fuse to make diploid nucleusnucleus
Mitosis and then meiosis produces 8 Mitosis and then meiosis produces 8 ascosporesascospores
16Sexual Reproduction in Sac Fungi
17Black Mold
18Tineas
The FungiThe Fungi 19Sac Fungi:Sac Fungi:Reproduction - YeastsReproduction - Yeasts
Term “yeasts” is loosely applied to Term “yeasts” is loosely applied to unicellular fungi, many of which are unicellular fungi, many of which are ascomycetesascomycetes
Budding is common form of asexual Budding is common form of asexual reproductionreproduction
Sexual reproduction results in the Sexual reproduction results in the formation of asci and ascosporesformation of asci and ascospores
When some yeasts ferment, they When some yeasts ferment, they produce ethanol and carbon dioxideproduce ethanol and carbon dioxide
The FungiThe Fungi 20Diversity of Fungi:Diversity of Fungi:The Club FungiThe Club Fungi
Phylum Basidomycota – 22,000 sppPhylum Basidomycota – 22,000 spp
Familiar toadstools, mushrooms, Familiar toadstools, mushrooms, bracket fungi, puffballs, stinkhorns – bracket fungi, puffballs, stinkhorns – some deadly poisonoussome deadly poisonous
Also plant diseases such as the smuts Also plant diseases such as the smuts and rustsand rusts
Mycelium composed of septate hyphaeMycelium composed of septate hyphae
The FungiThe Fungi 21The Club Fungi:The Club Fungi:ReproductionReproduction
Usually reproduce sexuallyUsually reproduce sexually
Haploid hyphae fuse, forming a Haploid hyphae fuse, forming a dikaryotic (n + n) myceliumdikaryotic (n + n) mycelium
Dikaryotic mycelium forms fruiting Dikaryotic mycelium forms fruiting bodies called basidiocarpsbodies called basidiocarps
Contain club-shaped structures called Contain club-shaped structures called basidiabasidia
Nuclear fusion followed by meiosis Nuclear fusion followed by meiosis produces basidiospores (up to produces basidiospores (up to 40,000,000 per hour)40,000,000 per hour)
22Club Fungi
23Club Fungi
The FungiThe Fungi 24The Club Fungi:The Club Fungi:Smuts and RustsSmuts and Rusts
Smuts and rusts are club fungi that parasitize Smuts and rusts are club fungi that parasitize cereal cropscereal crops Great economic importance because of annual Great economic importance because of annual crop lossescrop losses Do not form basidiocarpsDo not form basidiocarps
Life cycle of rusts often requires two different Life cycle of rusts often requires two different plant host species plant host species Black stem rust of wheat uses barberry bushesBlack stem rust of wheat uses barberry bushes Blister rust of white pine uses currant and Blister rust of white pine uses currant and gooseberry bushesgooseberry bushes
Eliminating these bushes in crop areas keeps Eliminating these bushes in crop areas keeps rusts in checkrusts in check
Wheat rustWheat rust Controlled by breeding new resistant strains of Controlled by breeding new resistant strains of wheatwheat
Requires continuous development, because rust Requires continuous development, because rust can mutatecan mutate
25Smuts & Rusts
The FungiThe Fungi 26Symbiotic Relationships:Symbiotic Relationships:LichensLichens
Symbiotic association between a fungus Symbiotic association between a fungus and a cyanobacterium or green algaand a cyanobacterium or green alga
Specialized fungal hyphae penetrate Specialized fungal hyphae penetrate photosynthetic symbiontphotosynthetic symbiont
Transfer nutrients directly to the fungusTransfer nutrients directly to the fungus
Possibly mutualistic, but fungal symbiont Possibly mutualistic, but fungal symbiont probably a parasite of photosynthetic probably a parasite of photosynthetic symbiontsymbiont
Photosynthetic symbiont independentPhotosynthetic symbiont independent
Fungal symbiont usually can’t grow aloneFungal symbiont usually can’t grow alone
The FungiThe Fungi 27Symbiotic Relationships:Symbiotic Relationships:LichensLichens
Three morphological types Three morphological types
Compact crustose lichens - seen on Compact crustose lichens - seen on bare rocks or on tree barkbare rocks or on tree bark
Fruticose lichens – shrub-likeFruticose lichens – shrub-like
Foliose lichens - leaf-likeFoliose lichens - leaf-like
Can live in areas of extreme Can live in areas of extreme conditions and contribute to soil conditions and contribute to soil formationformation
Sensitive indicators of air pollutionSensitive indicators of air pollution
28Lichen Morphology
The FungiThe Fungi 29Symbiotic Relationships:Symbiotic Relationships:MycorrhizaeMycorrhizae
Mutualistic relationships between soil fungi Mutualistic relationships between soil fungi and the roots of most familiar plantsand the roots of most familiar plants
Give plant greater absorptive surfaceGive plant greater absorptive surface
Help plants acquire mineral nutrients in poor Help plants acquire mineral nutrients in poor soilsoil
Fungal symbiont usually a sac fungusFungal symbiont usually a sac fungus
Hyphae may enter cortex of root, but not Hyphae may enter cortex of root, but not cytoplasmcytoplasm
Ectomycorrhizae form a mantle that is exterior Ectomycorrhizae form a mantle that is exterior to the root, and they grow between cell walls.to the root, and they grow between cell walls.
Endomycorrhizae penetrate only the cell wallsEndomycorrhizae penetrate only the cell walls
Earliest fossil plants have mycorrhizae Earliest fossil plants have mycorrhizae associated with themassociated with them
The FungiEnding Slide Chapter 23