The Kingdom Fungi Chapter 21

21-1 The Kingdom Fungi

What are Fungi? Fungi are eukaryotic heterotrophs that have cell walls made of chitin (a carbohydrate). Fungi DO NOT ingest their food, but rather they digest food OUTSIDE their bodies and the ABSORB it! (Fungi are decomposers) Reasons Fungi Not Plants! No chlorophyll Cell wall not Cellulose NO vascular tissue Do not photosynthesize (Not an autotroph)

Structure and Function of Fungi Multicellular (except yeasts) Composed of hyphae—thin filaments one cell thick Cross walls—cytoplasm and nuclei can move through openings Without cross walls—contain many nuclei

Hyphae Structure Close-Up Nuclei Cell wall Cytoplasm Cross wall Hyphae With Cross Walls Hyphae Without Cross Walls Section 21-1

Structure & Function of Fungi Except for yeasts, ALL fungi are multi-cellular and composed of tiny filaments called hyphae. The bodies of multicellular fungi are composed of many hyphae tangled together into a thick mass called a mycelium. The mycelium is well suited to absorb food. The fruiting body is a reproductive structure that develops from a mycelium that grows below the surface of the ground.

Fungi Structure Fruiting body Hyphae Mycelium Section 21-1

A Mushroom Fairy Ring Mushrooms emerge in a fairy ring from an underground fungal mycelium, growing outward from a central point where a single spore germinated, perhaps centuries ago.

Reproduction in Fungi Most fungi reproduce both asexually and sexually. Asexual: In some fungi, spores are produced in structures called sporangia. Sporangia are found at the tips of specialized hyphae called sporangiophores. Sexual: Sexual reproduction involves a gametangium - a gamete-forming structure produced when the hyphae of opposing mating types of fungi meet.

How Fungi Spread How Fungi Spread Fungal spores Scatter easily in the wind Must land in favorable environment Temperature Moisture Food Some are specialized to lure animals, flies Disperse spores over long distances FIGURE 22-2 Some fungi can eject spores A ripe earthstar mushroom, struck by a drop of water, releases a cloud of spores that will be dispersed by air currents.

21-2 Classification of Fungi Fungi are classified according to their structure and method of reproduction The 4 main groups of fungi are: Zygomycota (common molds) Ascomycota (sac fungi) Basidiomycota (club fungi) Deuteromycota (imperfect fungi)

Zygomycota – The Common Molds Zygomycetes are the familiar molds that grown on meat, cheese, and bread. Ex: Rhizopus stolonifer (black bread mold). the rootlike hyphae that anchor the fungus to the bread are called rhizoids the stem-like hyphae that run along the surface of the bread are called stolons

Figure 21-5 The Life Cycle of Rhizopus Section 21-2 p. 531 Zygospore (2N) Spores (N) Sporangium + Mating type (N) Stolons Rhizoids - Mating type (N) Sporangiophore Gametangia FERTILIZATION MEIOSIS Sexual Reproduction Asexual Reproduction Diploid Haploid

Zygomycota

Ascomycota – The Sac Fungi The phylum Ascomycota is named for the ascus, a reproductive structure that contains spores. Ascomycetes are the largest phyum in the kingdom Fungi. Some are large and some are microscopic. Examples: cup fungi (large) and yeasts (microscopic).

Figure 21-7 The Life Cycle of an Ascomycete Section 21-2 p. 533 Hypha (N) Conidiophore Conidia (N) + Mating type (N) - Mating type (N) 8 Ascospores (N) Ascus Zygote (2N) Ascus (N + N) Fruiting body (N + N) Hyphae (N + N) Gametangia Asci Hyphae (N) Diploid Haploid FERTILIZATION HYPHAE FUSE MEIOSIS Sexual Reproduction Asexual Reproduction

Morels are Ascomycete Fungi

Yeast is an Ascomycete Fungus Yeasts Unicellular fungi Ascomycetes—baking and brewing Budding—process of asexual reproduction—cell division Alcoholic fermentation to obtain energy Byproducts—carbon dioxide and alcohol

Yeast is an Ascomycete Fungus Yeasts are unusual, normally nonfilamentous ascomycetes that reproduce most commonly by budding. The yeast shown here is Candida, a common cause of vaginal infections. Candida sp.

Some Ascomycetes Scarlet Cup Fungus Morel (a) The cup-shaped fruiting body of the scarlet cup fungus (b) The morel, an edible delicacy. (Consult an expert before sampling any wild fungus—some are deadly!) Scarlet Cup Fungus Morel

Ascomycota

Sac Fungi - Ascomycota CUP FUNGI (visible to the eye) YEASTS (microscopic)

Basidiomycota – The Club Fungi The phylum Basidiomycota gets its name from a specialized reproductive structure (called a basidium) that resembles a club. Includes: Mushrooms Shelf fungi Puffballs Earthstars Jelly fungi Plant rusts Bird’s nest fungi

Figure 21-8 The Life Cycle of a Basidiomycete Section 21-2 p. 534 Fruiting body (N + N) Button Secondary mycelium (N + N) Primary mycelium (N) + Mating type (N) - Mating type (N) Basidiospores (N) Zygote (2N) Basidia (N + N) Gills lined with basidia Gills Stalk Base Cap FERTILIZATION HYPHAE FUSE Haploid Diploid MEIOSIS

Mushrooms – “Club Like” Fungi or Basidiomycete Fungi

Bracket Fungi – Basidiomycete Fungi

Some Basidiomycetes Shelf Fungi Giant Puffball The giant puffball Lycopedon giganteum may produce up to 5 trillion spores. Shelf fungi, the size of dessert plates, are conspicuous on trees. Giant Puffball

Basidiomycete or Club Fungi

Basidiomycota

The Club Fungi Diversity of Club Fungi Edible and Inedible Mushrooms Shelf fungi Puffballs Earthstars Jelly fungi Rusts Edible and Inedible Mushrooms Almost identical Some inedible can cause severe illness or death

Diversity of Club Fungi PUFFBALL EARTH STAR MUSHROOM SHELF FUNGI BIRD’S NEST FUNGI JELLY FUNGI

Deuteromycota – The Imperfect Fungi Deuteromycota is an extremely varied phylum composed of those fungi that are not placed in other phyla. The term imperfect implies that these fungi do not appear to have sexual reproduction. Ex: Penicillium notatum – the source of antibiotic penicillin.

Deutoeromycota

Deuteromycota (Imperfect Fungi) -Regarded as imperfect because they exhibit no sexual stage has been observed in their life cycle -Members are not closely related and are not necessarily similar in structure or appearance; do not share a common ancestry, polyphyletic = coming from many ancestors – hmm weird 

Truffles Truffles, rare ascomycetes (each about the size of a small apple), are a gastronomic delicacy.

Truffles are round, warty, fungi that are irregular in shape Truffles are round, warty, fungi that are irregular in shape. They vary from the size of a walnut to that of a man's fist. Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods, often commanding as much as $250 to $450 per pound. Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. The female pig becomes excited when she sniffs a chemical that is similar to the male swine sex attractant. The use of dogs to find truffles is also and option.

21-3 Ecology of Fungi All Fungi Are Heterotrophs Saprobes - Organisms that obtain food from decaying organic matter Parasites - which harm other orgnisms Symbionts - live in close and mutually beneficial association with other species Capture live animals Pleurotus ostreatus Lives on the sides of trees and trap worms to digest them

21-3 Ecology of Fungi Fungi as Decomposers Maintain equilibrium in nearly every ecosystem by recycling nutrients Release digestive enzymes that break down organic material into simple molecules which diffuse into the fungus

21-3 Ecology of Fungi Fungi as Parasites Corn smut Cause serious plant and animal diseases and a few cause diseases in humans Plant Diseases Smuts, mildews, rusts Corn smut Plant mildew Spruce rust

21-3 Ecology of Fungi Parasitic fungi cause serious plant and animal diseases: wheat rust mildew on fruit

Corn Smut This basidiomycete pathogen destroys millions of dollars’ worth of corn each year. Even a pest like corn smut has its admirers, though. In Mexico this fungus is known as huitlacoche and is considered to be a great delicacy.

Penicillium Penicillium growing on an orange. Reproductive structures, which coat the fruit’s surface, are visible, while hyphae beneath draw nourishment from inside. The antibiotic penicillin was first isolated from this fungus.

Other Basidiomycetes Rusts and Smuts Rust infecting wheat leaves Rust infecting a Leaf Whitrot Smut digesting old wood

21-3 Ecology of Fungi Human Diseases Athlete’s foot, ringworm Candida albicans (yeast)—oral thrush Bacteria and yeast in the human body keep each other in check

21-3 Ecology of Fungi Other Animal Diseases Cordyceps—grasshoppers in rain forests in Costa Rica

21-3 Ecology of Fungi Symbiotic Relationships Mutualistic (both benefit) Lichens Fungus and an alga or a cyanobacterium or both Live mostly on bare rock and in places that most other organisms cannot live Break down rock into soil Autotroph makes food, fungus absorbs water and nutrients and serves as an anchor

Lichens: Symbiotic Partnerships Algal Layer Most lichens have a layered structure bounded on the top and bottom by an outer layer formed from fungal hyphae. Attachments formed from fungal hyphae emerge from the lower layer and anchor the lichen to a surface, such as a rock or a tree. An algal layer in which the alga and fungus grow in close association lies beneath the upper layer of hyphae. Fungal Hyphae Attachment Structure

Lichens Covering a Rock A colorful encrusting lichen, growing on dry rock, illustrates the tough independence of this symbiotic combination of fungus and alga.

Lichens are mutualistic symbiotic organisms Lichens are mutualistic symbiotic organisms. They have an ____________ fungus and a _________ or cyanobacterial portion. There are three lichen growth forms which are predominant in nature: _____________________ _____________________________

Fruticose Crustose Foliose

Symbiotic Relationships Lichens A symbiotic associations between a fungus and a photosynthetic organism. Lichen can grow on dry, bare rock and are often the first organisms to inhabit an area (pioneer species). The lichen break down the bare rock, allowing other plants to grow. lichen

Symbiotic Relationships Mycorrhizae A symbiotic associations of plant roots and fungi. Fungi increases the surface area of the plants roots. Its presence is often necessary for the growth of many plants. mycorrhizae

21-3 Ecology of Fungi Mycorrhizae Plant roots and fungi Plant roots provide energy and fungus provides a large surface area for more absorption of water and minerals

Mycorrhizae Enhance Plant Growth Hyphae of mycorrhizae entwining about the root of an aspen tree. Plants grow significantly better in a symbiotic association with these fungi, which help make nutrients and water available to the roots. Mycorrhizae

Coenocytic = hyphae lack crosswalls Phylum Ex’s Characteristics Asexual Sexual Zygomycota Bread Mold Rhizopus a dung fungus Chitin cell walls Coenocytic = hyphae lack crosswalls Unflagel. spores drop from sporangia Gametangia fuse to create zygospore Ascomycota Yeast, morels, truffles Conidia on conidophores Hyphae + & - fuse to create ascospores in ascus Basidiomycota Mushrooms Puffballs, rusts, smuts Cross walls in hyphae Asexual by way of Conidophores which produce conidiospores Sexual when hyphae fuse in BASIDIA to produce basidiospores Fungi Imperfecti Deuteromycota Penicillium, Athlete’s Foot fungus, Tomato Blight Similar To Basidio and Zygomy Asexual by conidia which produce conidophores Sexual repro Not known