Presentation on theme: "True Fungi break down dead organic material provide numerous drugs"— Presentation transcript:
1 True Fungi break down dead organic material provide numerous drugs foods like mushroomsPlant and animal diseases
2 Characteristics of fungi Fungi exist primarily as filamentous threads, the hyphae, forming a mass, a mycelium. Normally never see the mycelium, only the fruiting bodies.Cell walls contain chitin.*Reproduction is due to fusion of hyphae*Fungi are heterotrophic by absorption
3 Groups of fungi Chytridiomycota (chytrids) Zygomycota (bread molds) Ascomycota (yeasts and sac fungi)Basidiomycota (club fungi)Deuteromycota (asexual forms of ascomycetes and basidiomycetes)
4 Generalised Life cycle of fungi Meiosisto give sporesFusion ofhyphae*NuclearfusionDikaryoticmyceliumgives fruitingbodyDiploidstageHaploidmyceliaof differentmatingtypesWith the exception of the chytrids, the life cycle follows the same generalised pattern. Haploid hyphae fuse to form a mycelium which contains nuclei from the two hyphae. The duration of this ‘dikaryotic’ phase is different in the differing groups of fungi and therefore characteristic.At some stage the nuclei fuse to form a diploid cell, and there is usually immediate meiosis to give spores.Not in chytrids*Zygomycetes - V. small fruiting bodyAscomycetes - small fruiting bodyBasidiomycetes - long-lived hyphae thena large fruiting body
6 Chytridiomycota (chytrids) The oldest fossil fungi so far known and may form a ‘missing link’ with protists.Flagellated zoospores fuse, their nuclei fuse then immediate meiosis to give spores
7 Zygomycota (bread molds) Important decomposersDominant haploid phase with dikaryon restricted to formation of zygosporangiumasexual spores are produced
8 The life cycle of a zygomycete Spores produced by mitosisZygosporesSpores producedby meiosisSporangiumforms bymitosisThe life cycle of a zygomyceteSpores germinateto give myceliumCoenocytic myceliaof 2 mating typesHyphaegrowto eachotherGametangiadevelopZygosporangiumdevelopsZygosporangiumformed
9 Ascomycota (yeasts and sac fungi) Sexual spores (ascospores) are produced in a specialized sac-like structure called an ascus on the surface of an ascocarp.Reproduced asexually by conidiaDecomposers that include economically important foods such as truffles and Morels and pests such as powdery mildews and ergots. Yeasts used in baking and brewing.
10 Life cycle of an ascomycete Nuclear fusion thenAscospores in asciby meiosisLife cycle of an ascomyceteHaploidseptate hyphaeAnther-idium(‘male’)Asco-gonium‘female’Dikaryotic hyphae
11 Sporing structures (ascocarps) A vegetative layer of ‘sterile’ dikaryotic hyphae (2 nuclei) forms the body of the ascocarp with a layer of asci on the surface (produce spores)
13 Tissues within the ascocarp Cup fungiMorelsFlask fungiSterile body of ascocarp formed from dikaryotic hyphaeLayer of asci
14 Basidiomycota (club fungi) Septate hyphaeProduce long-lived dikaryons (mycelia where the cells have 2 nuclei)Produce sporing structures, the basidia, on basidiocarps.Wood rotting fungiRustsSmutsMushroomsPuffballsLife cycle a bit like ascomycetes, but individual spores produced
15 Yeasts Unicellular forms of ascomycetes and basidiomycetes. Some reproduce sexually some don’t.BakingBrewingHuman pathogens e.g. Candida
16 Deuteromycota (asexual forms of ascomycetes and basidiomycetes) No sexual stages known and propagate solely by spores called conidia on structures called conidiaphores.Includes commercially important species such as Penicillium (gives penicillin from fungal fermentations)ConidiaConidiophoreMycelium
17 LichensLichens are unusual creatures. A lichen is a combination of two organisms which live together intimately. Most of the lichen is composed of fungal filaments, but living among the filaments are algal cells, usually from a green alga or a Cyanobacterium.