Fungi

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4

Slide 23

Ascomycetes

Ascomycetes (phylum Ascomycota) live in marine, freshwater, and terrestrial habitats.

The phylum is defined by production of sexual spores in saclike asci, usually 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.

Slide 24

Ascomycetes - sac fungi

Tuber melanosporum, a truffle

Morchella esculenta,

the tasty morel

Slide 25

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 is a model organism with a well-studied genome.

Slide 26

Key

Haploid (n)

Diploid (2n)

Dikaryotic (n + n)

Conidiophore

Mycelium

ASEXUAL

REPRODUCTION

Germination

Hypha

PLASMOGAMY

Haploid spores (conidia)

Conidia;

mating type (–)

Mating

type (+)

SEXUAL

REPRODUCTION

Dikaryotic

hyphae

Ascus

(dikaryotic)

Mycelia

KARYOGAMY

Diploid nucleus

(zygote)

Germination

Asci

Dispersal

Dispersal

Ascocarp

Eight

ascospores

Four

haploid

nuclei

MEIOSIS

The life cycle of Neurospora, an ascomycete

Slide 27

Basidiomycetes

Basidomycetes (phylum Basidiomycota) include mushrooms, puffballs, and shelf fungi, mutualists, 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.

Slide 28

Basidiomycetes club fungi

Shelf fungi, important

decomposers of wood

Maiden veil fungus

(Dictyphora), a

fungus with an

odor like rotting

meat

Puffballs emitting

spores

Slide 29

Concept 31.5: Fungi play key roles in nutrient cycling, ecological interactions, and human welfare

Fungi interact with other organisms in many ways.

Fungi are efficient decomposers. They perform essential recycling of chemical elements between the living and nonliving world.

Fungi form mutualistic relationships with plants, algae, cyanobacteria, and animals.