Kingdom Fungi

Outline Protists versus Fungi Phylum Chytridomycota Phylum Zygomycota Phylum Ascomycota Phylum Basidiomycota Phylum Deuteromycota Lichens

Distinctions Between Protista and Fungi All true fungi are filamentous or unicellular heterotrophs, most of which absorb their food in solution through cell walls (saprobes). Members of Kingdom Fungi are placed in five phyla. With the exception of some chytrids (pronounced kitt-ridds) and all yeasts, all are filamentous. Most lack motile cells.

Kingdom Fungi Phylum Chytridomycota (The Chytrids) Simple, mostly one-celled organisms. Some parasitize pollen grains, and other are saprobic. Some are in the form of a spherical cell with branching threads called rhizoids which are used for anchoring the chytrid to its food source. Many reproduce only asexually through the production of zoospores within a spherical cell. Sexual reproduction by fusion of motile haploid gametes.

Fig. 19.2

Kingdom Fungi Phylum Zygomycota (Coenocytic True Fungi) Black bread molds are the best-known members of this phylum. Rhizopus is a well-known representative.

Reproduction in Rhizopus (bread mold) Asexual Sporangiophores grow upright and produce sporangia at their tips Numerous spores produced in each sporangium Sexual Conjugation of different mating strains Formation of progametangia Gametangia merge, becoming large multinucleate cell Wall develops around cell, forming the zygospore

Fig. 19.5

Human and Ecological Relevance of Zygomycetes A few species used as food sources. - tempeh and sufu (Chinese cheese). Industrial Uses Pharmaceuticals Yellow pigment for coloring margarine Meat tenderizer

Kingdom Fungi Phylum Ascomycota (Sac Fungi) Truffles are reproductive bodies of representatives of the phylum ascomycetes. Most produce mycelia with hyphae partitioned into individual cylindrical cells (non coenocytic). Asexual Reproduction By means of spores produced outside of a sporangium (conidia) on conidiophores. Yeasts - Budding

Fig. 19.6

Sexual Reproduction of Ascomycetes Involves formation of an ascus Male antheridia produced on one hypha, female ascogonia on other Male nuclei migrate into ascogonium Ascogenous hyphae formed At maturity, pairs of nuclei unite forming 2n nuclei Diploid nuclei undergo meiosis; these nuclei become nuclei of ascospores Ascospores (n) released into air

Phylum Ascomycota Human and Ecological Relevance Truffles and morels have been prized food for centuries Ergot fungus may infect rye and other grains. Ergotism may occur in those who eat the contaminated bread. Ergot drugs are medicinally useful in small amounts. Initial source for the manufacture of LSD.

Fig. 19.10

Fig. 19.11

Phylum Ascomycota Human and Ecological Relevance Yeast enzymes aid in preparation of baked goods. Fermentation Yeasts used in production of glycerol. Explosives Plant Diseases Dutch Elm Disease Chestnut Blight

The Basidiomycetes (Club Fungi) - Habitat: -i- Saprophytes Phylum Basidiomycota The Basidiomycetes (Club Fungi) - Habitat: -i- Saprophytes - Mushrooms (toadstools) - Puffballs, earth stars, jelly fungi, stinkhorns -ii- Parasites - Shelf or bracket fungi - Rusts, smuts - Shape: - Mycelium septate with pores - Uninucleate or binucleate stages of mycelium

Sexual Reproduction a) Hyphae of mycelium are monokaryotic b) Hyphal cells of compatible mating types may unite, initiating a new dikaryotic mycelium c) Formation of clamp connection, with one nucleus migrating into clamp d) Mitosis and formation of crosswalls e) Dikaryotic mycelium may become very dense, forming the button, which may penetrate the surface and expand into the basidiocarp (mushroom) f) Gill of mushroom has numerous basidia g) As each basidium matures, the two nuclei unite, and then undergo meiosis; the four nuclei become the nuclei of the four basidiospores Asexual Reproduction Infrequent mainly through conidia .

Phylum Basidiomycota Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Sexual Reproduction in Basidiomycota

Sexual Reproduction in Basidiomycota Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Sexual Reproduction in Basidiomycota Fairy Rings Boletes Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Sexual Reproduction in Basidiomycota Shelf Fungi Bird’s Nest Fungi Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Sexual Reproduction in Basidiomycota Smuts Rusts Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Phylum Basidiomycota Human and Ecological Relevance Poisonous Fewer than 75 of the approximately 25,000 described species are poisonous. Death Angel mushrooms are very poisonous. Thioctic acid used as antidote. Shiitake (Black Forest) Mushrooms High in protein, calcium, phosphorous, and iron. Lentinacin extract lowers blood cholesterol and exhibits antiviral activity by inducing the formation of interferon. Nutrient Recycling Cultivation for food: Agaricus bisporus

The Deuteromycetes (Imperfect Fungi) Phylum Deuteromycota The Deuteromycetes (Imperfect Fungi) Examples: parasites of protozoans and small animals, nematode trappers, forms cultivated by ants and termites, and mycorrhizal fungi. Fungi for which a sexual stage has not been observed. Grouped together in an artificial phylum. All reproduce by conidia. Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Human and Ecological Relevance Penicillium Molds Antibiotics Phylum Deuteromycota Human and Ecological Relevance Penicillium Molds Antibiotics Gourmet Cheese Aspergillus Citric Acid Soy Sauce Aspergilloses (Respiratory Disease) Aflatoxin (Carcinogen) Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

Lichens Consists of a fungus and an alga intimately associated in a spongy thallus. Photosynthetic component supplies the food while the fungus protects the photosynthetic organisms from harmful light intensities and absorbs and retains water and minerals. Three genera of green algae and one genus of cyanobacterium are involved in 90% of all lichen species.

Lichens Lichen species are identified according to their fungus. Grow very slowly, and are capable of living extremely long periods of time. Gelatinous substance in thallus allows them to withstand alternating wet and dry periods.

Lichens Usually consist of three or four layers: Upper Cortex - Protective layer Algal Layer - Contain algal cells. Medulla - Hyphae Lower Cortex - Covered with Rhizines.

Lichens Usually grouped into three major growth forms: Crustose - Attached to or embedded in their substrate over their entire lower surface. Foliose - Contain leaf-like thalli which often overlap. Fruticose - May resemble miniature upright shrubs, or hang down in festoons from branches.

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Lichens Fungal component of all lichens are of the sac fungi and usually reproduces sexually, but lichens are naturally dispersed in nature asexually. Sexual reproduction in lichens is similar to that of the sac fungi except ascomata produce spores continuously for many years.

Lichens Human and Ecological Relevance Exceptionally sensitive to pollution. Sulfur Dioxide Nuclear Radiation Degradation of historic structures. Food Supplements Antibiotic Properties

Review Protists versus Fungi Phylum Chytridomycota Phylum Zygomycota Phylum Ascomycota Phylum Basidiomycota Phylum Deuteromycota Lichens

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