Multicellular Fungus: hyphae … Reproductive structure Hyphae Spore-producing structures Figure 31.2 Structure of a multicellular fungus 20 µm Mycelium

Cell wall Cell wall Nuclei Pore Septum Nuclei (a) Septate hypha Two forms of hyphae Cell wall Cell wall Nuclei Pore Septum Nuclei Figure 31.3 Two forms of hyphae (a) Septate hypha (b) Coenocytic hypha

Fungus - have specialized hyphae Nematode 25 µm (a) Hyphae adapted for trapping and killing prey Plant cell wall Fungal hypha Figure 31.4 Specialized hyphae Plant cell Plant cell plasma membrane Haustorium (b) Haustoria - penetrate cell walls of plants ++ or +-

Life Cycle of Fungi PLASMOGAMY KARYOGAMY Haploid (n) Heterokaryotic Key Haploid (n) Heterokaryotic stage Heterokaryotic (unfused nuclei from different parents) PLASMOGAMY (fusion of cytoplasm) Diploid (2n) KARYOGAMY (fusion of nuclei) Spore-producing structures Zygote 2n SEXUAL REPRODUCTION Spores ASEXUAL REPRODUCTION Mycelium Figure 31.5 Generalized life cycle of fungi MEIOSIS GERMINATION GERMINATION Spores

Penicillium: a mold that decomposes food Penicillium: a mold that decomposes food. Mold produce spores asexually by mitosis. 2.5 µm Figure 31.6 Penicillium, a mold commonly encountered as a decomposer of food

The yeast Saccharomyces cerevisiae in several stages of asexual reproduction by budding. Parent cell Figure 31.7 The yeast Saccharomyces cerevisiae in several stages of budding (SEM) Bud

Fungi and their close relatives Animals (and their close protistan relatives) UNICELLULAR, FLAGELLATED ANCESTOR Nucleariids Opisthokonts Chytrids Figure 31.8 Fungi and their close relatives Fungi Other fungi

Fungus Diversity Figure 31.11 Fungal diversity Hyphae 25 µm Chytrids (1,000 species) Zygomycetes (1,000 species) Fungal hypha Glomeromycetes (160 species) Ascomycetes (65,000 species) Figure 31.11 Fungal diversity Basidiomycetes (30,000 species)

Life Cycle of the zygomycete Rhizopus black bread mold Key Haploid (n) Heterokaryotic (n + n) Diploid (2n) PLASMOGAMY Mating type (+) Gametangia with haploid nuclei Mating type (–) 100 µm Young zygosporangium (heterokaryotic) Rhizopus growing on bread SEXUAL REPRODUCTION Dispersal and germination Zygosporangium Sporangia KARYOGAMY Figure 31.13 The life cycle of the zygomycete Rhizopus stolonifer (black bread mold) Spores Diploid nuclei Sporangium ASEXUAL REPRODUCTION MEIOSIS Dispersal and germination 50 µm Mycelium

Some zygomycetes, such as Pilobolus, can actually “aim” their sporangia toward conditions associated with good food sources. Figure 31.14 Pilobolus aiming its sporangia 0.5 mm

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

The life cycle of Neurospora, an ascomycete Conidia; mating type (–) Haploid spores (conidia) Key Haploid (n) Dikaryotic (n + n) Diploid (2n) Dispersal Germination Mating type (+) ASEXUAL REPRODUCTION 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 The life cycle of Neurospora, an ascomycete

Basidiomycetes club fungi Maiden veil fungus (Dictyphora), a fungus with an odor like rotting meat Basidiomycetes club fungi Puffballs emitting spores Shelf fungi, important decomposers of wood Figure 31.18 Basidiomycetes (club fungi)

Fungus-gardening insects: Leaf-cutting ants depend on fungus to digest plant material to a form the insects can use for their nutrition + +. Figure 31.22 Fungus-gardening insects For the Discovery Video Leafcutter Ants, go to Animation and Video Files.

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

Anatomy of a common fungal ascomycete lichen Ascocarp of fungus Soredia Fungal hyphae Algal layer Figure 31.24 Anatomy of an ascomycete lichen (colorized SEM) Algal cell 20 µm Fungal hyphae

Fungal Diseases in Plants Figure 31.25 Examples of fungal diseases of plants For the Discovery Video Fungi, go to Animation and Video Files. (a) Corn smut on corn (b) Tar spot fungus on maple leaves (c) Ergots on rye

Staphylococcus Penicillium Zone of inhibited growth Penicillium: Fungal production of an Antibiotic The mold penicillium produces an antibiotic that inhibits bacteria growth resulting in a clear area between the mold and the bacteria Staphylococcus Penicillium Zone of inhibited growth Figure 31.26 Fungal production of an antibiotic

Review

You should now be able to: List the characteristics that distinguish fungi from other multicellular kingdoms. Discuss mycorrhizal fungi. Describe the processes of plasmogamy and karyogamy. Describe the evidence that multicellularity evolved independently in fungi and animals.

Describe the life cycles of Rhizopus stolonifer and Neurospora crassa. Distinguish among zygomycetes, ascomycetes, and basidiomycetes. Describe some of the roles of fungi in ecosystems, lichens, animal-fungi mutualistic symbioses, food production, and medicine and as pathogens.