What is the biggest organism in this Oregonian forest?

Hint, it is pictured

The honey mushroom fungus

Fun-gi vids pig decomposition time-lapse fungus time-lapse growing mold time-lapse parasitic fungi time-lapse

Chapter 31 Fungi

Concept 31.1: Fungi are heterotrophs that feed by absorption Fungi are heterotrophs and absorb nutrients from outside of their body Fungi use enzymes to break down a large variety of complex molecules into smaller organic compounds Fungi exhibit diverse lifestyles Decomposers rabbit decomposing Parasites previously shown, with new bonus mushroom and slime mold time-lapse Mutualists © 2011 Pearson Education, Inc.

Animation: Fungal Reproduction and Nutrition Right-click slide / select “Play” © 2011 Pearson Education, Inc.

A mycelium’s structure maximizes its surface area-to-volume ratio Anatomy basics Fungi consist of mycelia, networks of branched hyphae adapted for absorption A mycelium’s structure maximizes its surface area-to-volume ratio Fungal cell walls contain chitin © 2011 Pearson Education, Inc.

Reproductive structure Figure 31.2 Reproductive structure Hyphae Spore-producing structures Figure 31.2 Structure of a multicellular fungus. 60 m Mycelium

TWO FORMS OF HYPHAE Cell wall Nuclei Cell wall Pore Septum Nuclei (a) Septate hypha (b) Coenocytic hypha Figure 31.3 Two forms of hyphae.

1 pinch of soil can contain 1 km of hyphae

How much hyphae did she eat?

Some unique fungi have specialized hyphae called haustoria that allow them to penetrate the tissues of their host Hyphae Nematode 25 m (a) Hyphae adapted for trapping and killing prey Fungal hypha Plant cell wall Figure 31.4 Specialized hyphae. Plant cell Plant cell plasma membrane Haustorium (b) Haustoria

Mycorrhizae are mutually beneficial relationships between fungi and plant roots, which most vascular plants have Ectomycorrhizal fungi form sheaths of hyphae over a root and also grow into the extracellular spaces of the root cortex Arbuscular mycorrhizal fungi extend hyphae through the cell walls of root cells and into tubes formed by invagination of the root cell membrane Which is pictured  ? Which is pictured on the previous slide? © 2011 Pearson Education, Inc.

Concept 31.2: Fungi produce spores through sexual or asexual life cycles Fungi propagate themselves by producing vast numbers of spores, either sexually or asexually, or both © 2011 Pearson Education, Inc.

Fungi life cycle paths can be funky Key Haploid (n) Heterokaryotic Diploid (2n) Spore-producing structures Spores ASEXUAL REPRODUCTION Mycelium Figure 31.5 Generalized life cycle of fungi. GERMINATION

Spore-producing structures Fungi life cycle paths can be funky Key Haploid (n) Heterokaryotic stage PLASMOGAMY Heterokaryotic Diploid (2n) Spore-producing structures KARYOGAMY SEXUAL REPRODUCTION Spores ASEXUAL REPRODUCTION Mycelium Zygote Figure 31.5 Generalized life cycle of fungi. GERMINATION

Spore-producing structures Fungi life cycle paths can be funky Key Haploid (n) Heterokaryotic stage PLASMOGAMY, based on pheromone compatibility Heterokaryotic Diploid (2n) Spore-producing structures KARYOGAMY SEXUAL REPRODUCTION Spores ASEXUAL REPRODUCTION Mycelium Zygote Figure 31.5 Generalized life cycle of fungi. GERMINATION MEIOSIS GERMINATION Spores

© 2011 Pearson Education, Inc.

Asexual Reproduction In addition to sexual reproduction, many fungi can reproduce asexually Molds produce haploid spores by mitosis and form visible mycelia © 2011 Pearson Education, Inc.

Figure 31.7 CHECK-IN Q Yeast are unicellular and reproduce by budding. Then what makes them fungi? 10 m Parent cell Figure 31.7 The yeast Saccharomyces cerevisiae in several stages of budding (SEM). Bud

Concept 31.3: The ancestor of fungi was an aquatic, single-celled, flagellated protist DNA evidence suggests that Fungi are most closely related to unicellular nucleariids Animals are most closely related to unicellular choanoflagellates Based on this, did fungi and animals split before or after the emergence of multicellularity? © 2011 Pearson Education, Inc.

The Move to Land If fungi are heterotrophic, how does it make sense that they were among the first land colonizers? © 2011 Pearson Education, Inc.

The Move to Land If fungi are eukaryotic, how does it make sense that they were among the first land colonizers? © 2011 Pearson Education, Inc.

Concept 31.4: Fungi have radiated into a diverse set of lineages Molecular analyses have helped clarify evolutionary relationships among fungal groups, although areas of uncertainty remain © 2011 Pearson Education, Inc.

Figure 31.11 Exploring: Fungal Diversity Hyphae 25 m Chytrids (1,000 species) Zygomycetes (1,000 species) Fungal hypha 25 m Glomeromycetes (160 species) Ascomycetes (65,000 species) Figure 31.11 Exploring: Fungal Diversity Basidiomycetes (30,000 species)

Chytrids Chytrids (phylum Chytridiomycota) are found in freshwater and terrestrial habitats They can be decomposers, parasites, or mutualists Molecular evidence supports the hypothesis that chytrids diverged early in fungal evolution Chytrids are unique among fungi in having flagellated spores, called zoospores © 2011 Pearson Education, Inc.

Video: Allomyces Zoospore Release © 2011 Pearson Education, Inc.

Video: Phlyctochytrium Zoospore Release © 2011 Pearson Education, Inc.

Zygomycetes The zygomycetes (phylum Zygomycota) exhibit great diversity of life histories They include fast-growing molds, parasites, and commensal symbionts The life cycle of black bread mold (Rhizopus stolonifer) is fairly typical of the phylum Its hyphae are coenocytic Asexual sporangia produce haploid spores © 2011 Pearson Education, Inc.

Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN02 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN02

Flagellum Figure 31.13 PLASMOGAMY Mating type () Gametangia with haploid nuclei Mating type () Rhizopus growing on bread 100 m Young zygosporangium (heterokaryotic) SEXUAL REPRODUCTION Dispersal and germination Zygosporangium Flagellum KARYOGAMY Sporangia Figure 31.13 The life cycle of the zygomycete Rhizopus stolonifer (black bread mold). Diploid nuclei Sporangium ASEXUAL REPRODUCTION MEIOSIS Key Dispersal and germination Haploid (n) Heterokaryotic (n  n) Mycelium 50 m Diploid (2n)

The zygomycetes are named for their sexually produced zygosporangia Zygosporangia are the site of karyogamy and then meiosis Zygosporangia, which are resistant to freezing and drying, can survive unfavorable conditions Some zygomycetes, such as Pilobolus, can actually “aim” their sporangia toward conditions associated with good food sources © 2011 Pearson Education, Inc.

Figure 31.14 Figure 31.14 Pilobolus aiming its sporangia. 0.5 mm Pilobolus aiming its sporangia toward light as that is where edible vegitation would be growing (grass). Grass is eaten, spores spread in feces.

Glomeromycetes The glomeromycetes (phylum Glomeromycota) were once considered zygomycetes They are now classified in a separate clade Glomeromycetes form arbuscular mycorrhizae © 2011 Pearson Education, Inc.

Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN03 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN03

Figure 31.15 Figure 31.15 Arbuscular mycorrhizae. 2.5 m

Ascomycetes Ascomycetes (phylum Ascomycota) live in marine, freshwater, and terrestrial habitats Ascomycetes produce sexual spores in saclike asci contained in fruiting bodies called ascocarps Ascomycetes are commonly called sac fungi Ascomycetes vary in size and complexity from unicellular yeasts to elaborate cup fungi and morels © 2011 Pearson Education, Inc.

Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN04 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN04

Morchella esculenta, the tasty morel Figure 31.16 Morchella esculenta, the tasty morel Tuber melanosporum, a truffle Figure 31.16 Ascomycetes (sac fungi).

Ascomycetes include plant pathogens, decomposers, and symbionts Ascomycetes reproduce asexually by enormous numbers of asexual spores called conidia Conidia are not formed inside sporangia; they are produced asexually at the tips of specialized hyphae called conidiophores Neurospora crassa, a bread mold, is a model organism with a well-studied genome © 2011 Pearson Education, Inc.

Figure 31.17 The life cycle of Neurospora crassa, an ascomycete. Conidia; mating type () Key Dispersal Haploid (n) Germination Mating type () Dikaryotic (n  n) ASEXUAL REPRODUCTION Diploid (2n) Hypha PLASMOGAMY Ascus (dikaryotic) Conidiophore Mycelia Dikaryotic hyphae Mycelium Germination SEXUAL REPRODUCTION KARYOGAMY Dispersal Diploid nucleus (zygote) Asci Eight ascospores Ascocarp Figure 31.17 The life cycle of Neurospora crassa, an ascomycete. Four haploid nuclei MEIOSIS

Basidiomycetes Basidomycetes (phylum Basidiomycota) include mushrooms, puffballs, and shelf fungi, mycorrhizae, and plant parasites The phylum is defined by a clublike structure called a basidium, a transient diploid stage in the life cycle The basidiomycetes are also called club fungi Many basidiomycetes are decomposers of wood © 2011 Pearson Education, Inc.

Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN05 Chytrids Zygomycetes Glomeromycetes Ascomycetes Basidiomycetes Figure 31.UN05

Puffballs emitting spores Figure 31.18 Shelf fungi Puffballs emitting spores Figure 31.18 Basidiomycetes (club fungi). Maiden veil fungus (Dictyphora)

Mushrooms are examples of basidiocarps The life cycle of a basidiomycete usually includes a long-lived dikaryotic mycelium In response to environmental stimuli, the mycelium reproduces sexually by producing elaborate fruiting bodies called basidiocarps Mushrooms are examples of basidiocarps The numerous basidia in a basidiocarp are sources of sexual spores called basidiospores © 2011 Pearson Education, Inc.

Figure 31.19 The life cycle of a mushroom-forming basidiomycete. Dikaryotic mycelium Key PLASMOGAMY Haploid (n) Dikaryotic (n  n) Mating type () Diploid (2n) Mating type () Haploid mycelia Gills lined with basidia SEXUAL REPRODUCTION Basidiocarp (n  n) Dispersal and germination Basidiospores (n) Basidium with four basidiospores Basidia (n  n) Basidium Figure 31.19 The life cycle of a mushroom-forming basidiomycete. Basidium containing four haploid nuclei KARYOGAMY MEIOSIS Diploid nuclei 1 m Basidiospore

Basidiomycetes can produce mushrooms quickly Figure 31.20 Figure 31.20 A fairy ring. Basidiomycetes can produce mushrooms quickly Some species may produce “fairy rings”

Imagine a fungi-free world…

Concept 31.5: Fungi play key roles in nutrient cycling, ecological interactions, and human welfare Fungi interact with other organisms as decomposers, mutualists, and pathogens © 2011 Pearson Education, Inc.

Fungi as Decomposers/Nutrient recylers Fungi are efficient decomposers of organic material including cellulose and lignin Fungi are also used in bioremediation projects © 2011 Pearson Education, Inc.

Fungi as Mutualists © 2011 Pearson Education, Inc.

Fungus-Plant Mutualisms Mycorrhizae are enormously important in natural ecosystems and agriculture Plants harbor harmless symbiotic endophytes, fungi that live inside leaves or other plant parts Endophytes make toxins that deter herbivores and defend against pathogens Most endophytes are ascomycetes © 2011 Pearson Education, Inc.

Endophyte not present; pathogen present (EP) Figure 31.21 RESULTS Endophyte not present; pathogen present (EP) Both endophyte and pathogen present (EP) 30 15 20 10 Leaf mortality (%) Leaf area damaged (%) Figure 31.21 Inquiry: Do endophytes benefit a woody plant? 10 5 EP EP EP EP

Fungi-animal symbiosis Figure 31.22 Fungus-gardening insects.

Lichens A lichen is a symbiotic association between a photosynthetic microorganism and a fungus The photosynthetic component is green algae or cyanobacteria The fungal component is most often an ascomycete The symbioses are so complete that lichens are given scientific names © 2011 Pearson Education, Inc.

A foliose (leaflike) lichen Figure 31.23 A foliose (leaflike) lichen Crustose (encrusting) lichens Figure 31.23 Variation in lichen growth forms. A fruticose (shrublike) lichen

Ascocarp of fungus Soredia Fungal hyphae Algal layer 50 m Lichen anatomy Ascocarp of fungus Soredia Fungal hyphae Algal layer 50 m Figure 31.24 Anatomy of an ascomycete lichen (colorized SEM). Fungal hyphae Algal cell

Lichens are important pioneers on new rock and soil surfaces Lichens may have helped the colonization of land by plants 550–600 million years ago © 2011 Pearson Education, Inc.

Fungi as Pathogens About 30% of known fungal species are parasites or pathogens, mostly on or in plants Each year, 10% to 50% of the world’s fruit harvest is lost due to fungi Some fungi that attack food crops are toxic to humans © 2011 Pearson Education, Inc.

Tar spot fungus on maple leaves Figure 31.25 (b) Tar spot fungus on maple leaves Figure 31.25 Examples of fungal diseases of plants. (a) Corn smut on corn (c) Ergots on rye

Fungi caused Salem Witch Trials? Ergotism is characterized by gangrene, nervous spasms, burning sensations, hallucinations, and temporary insanity Ergots contain lysergic acid, the raw material for LSD © 2011 Pearson Education, Inc.

Global amphibian populations are down due to fungal infection (mycosis) California Sixty Lake Basin 2004 Yellow-legged frogs killed by B. dendrobatidis infection N 2005 Figure 31.26 Impact: Amphibians Under Attack Key Boundary of chytrid spread 2006 Lake status in 2009: 2007 2008 Frog population extinct Treatment lake: frogs treated with fungicides and released

Practical Uses of Fungi Humans eat many fungi and use others to make cheeses, alcoholic beverages, and bread Some fungi are used to produce antibiotics for the treatment of bacterial infections For example, the ascomycete Penicillium © 2011 Pearson Education, Inc.

Fungal production of antibiotic Staphylococcus Penicillium Zone of inhibited growth Figure 31.27 Fungal production of an antibiotic.

Distinguishing Features of Morphology and Life Cycles Figure 31.UN06 Fungal Phylum Distinguishing Features of Morphology and Life Cycles Chytridiomycota (chytrids) Flagellated spores Zygomycota (zygote fungi) Resistant zygosporangium as sexual stage Glomeromycota (arbuscular mycorrhizal fungi) Arbuscular mycorrhizae formed with plants Ascomycota (ascomycetes, or sac fungi) Sexual spores (ascospores) borne internally in sacs called asci; vast numbers of asexual spores (conidia) produced Figure 31.UN06 Basidiomycota (basidiomycetes, or club fungi) Elaborate fruiting body (basidiocarp) containing many basidia that produce sexual spores (basidiospores)

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