Chapter 20- Fungi

Fungi-General Characteristics

Fungal cells possess:

Unlike plants and algae, fungi lack:

Fungal cells have protective cell walls

Most fungi are composed of hyphae.

Lengths of hyphae may also form rhizomorphs.

Fungal reproductive structures visible with unaided eye

-nuclei

-mitochondria

-endomembrane system

-cytoskeleton system

Typical features of an eukaryotic cell

-plastids

-the ability to conduct photosynthesis

prokaryotes – peptidoglycan

algae – cellulose

fungi- chitin, a nitrogen-rich polysaccharide

Most fungi are terrestrial, but some occupy aquatic environments.

Hyphae – microscopic threadlike branched filaments that

provide a large surface area for obtaining

nutrients.

Mycelium – A mass of interconnected hyphae.

Rhizomorphs transfer water to portions of the fungal

bodies in low moisture environments.

Other types of fungi occur in single cells:

Fungal nutrition

The act of feeding pushes a hypha into a food mass and drives food

through the mycelium

The change in solute concentration causes water to enter the hypha.

The hypha secretes enzymes that break down large molecules.

Other types of fungi occur unorganized fruiting bodies:

http://microbeonline.com/wp-

content/uploads/2014/10/LPCB-Mount-and-Aspergillus.jpg

Small solute molecules enter the hypha.

The added volume of water creates pressure that

expands the tip of the hyphae and pushes it forward.

Kingdom Fungi

DNA and other evidence indicate modern fungi arose

from a single common ancestor.

Fungi are classified into 5 phyla

1)Chytridiomycota

2) Zygomycota

3) Glomeromycota

4) Ascomycota

5) Basidiomycota

Fungi-General Characteristics

Kingdom Fungi- Sexual life cycle with a dikaryotic stage

Plasmogamy is the fusion of the cytoplasm, but not fusion of the nuclei.

Karyogamy is the fusion of the nuclei.

Chytridiomycota

-Only fungi that produce flagellate cells

http://bio1151.nicerweb.com/Locked/media/ch31/Chytrids.html http://bama.ua.edu/~chytrid/

http://bama.ua.edu/~chytrid/

Above: Batrachochytrium dendrobatidis (Bd), the chytrid fungus

responsible for many amphibian declines. Photograph by Erica

Bree Rosenblum, University of California at Berkeley. Below:

Hypsiboas polytaenius from Brazil, one of the many amphibian

species infected by Bd. Photograph by David Rodriguez, Cornell

University. Credit: Erica Bree Rosenblum

http://phys.org/news/2013-05-sequencing-reveals-complex-history-amphibian-killing.html

Top picture: A Chytrid infection shows

in the pink underbelly of this green tree

frog. Bottom picture: This great barred

frog has a severe Chytrid infection,

seen in its lethargic pose and peeling

skin.

http://www.nationalparks.nsw.gov.au/np

ws.nsf/Content/Frog+Chytrid+fungus

Since frogs use their skin in

respiration, this makes it difficult for

the frog to breathe.

The fungus also damages the

nervous system, affecting the frog's

behavior

Chytridiomycota

http://www.jochemnet.de/fiu/BSC1011/BSC1011_6/img004.gif

Zygomycota

Ex: Rhizopus (black bread mold)

http://www4.uwsp.edu/biology/courses/botlab/lab17a.htm Ex: Pilobolus

Asexual life cycle

Passively drifting meiospores that

settle on food and grow into large

aseptate mycelium.

Sporangiophores grow into the air, and

swell at the tip to form mitosporangia.

Sexual life cycle

Compatible Rhizopus mycelia ( + and –

mating types) meet, and grow special

hyphae that meet at the tips.

Cross walls form behind the tips and

wall off 2 cells (gametangia).

Nuclear fusion occurs to produce a 2n

zygote and develops into a thick-walled

zygospore.

Zygospore undergoes meiosis and hypha (n)

grow out of the zygospore.

Chytridiomycota

Glomeromycota

Many fungi that partner with green plants in symbiotic

associations known as mycorrhizae.

Arbuscular mycorrhizal fungi or AM fungi

Some of the oldest plant fossils contain mycorrhizal fungi.

Over 80% of wild plants are estimated to have such fungal partners.

http://mycorrhizas.info/vam.html

A group of fungi not known to grow separately from plant roots.

Botanists have postulated that plants and Glomeromycota

moved from water to land as partners.

Ascomycota- sac fungi

Sexual reproduction

Plasmogamy of specialized cells of 2 genetically distinct parents.

Dikaryotic hyphae (n + n) contain nuclei from each parent and form the fertile portion of the fruiting body.

In the surface cells of the fruiting body, the 2 nuclei fuse (karyogamy) to form a diploid zygote.

The zygote undergoes meiosis and forms 8 haploid spores (ascospores).

Ascomycota- types of ascocarps

apothecia perithecia cleistothecia

(perithecium)

Claviceps purpurea

ergot

Blumeria (Erysiphe) graminis

powdery mildew

"Barleypowderymildew". Licensed under

CC BY 3.0 us via Wikimedia Commons -

http://commons.wikimedia.org/wiki/File:Barl

eypowderymildew.jpg#/media/File:Barleyp

owderymildew.jpg

© Carolina Biological/Visuals Unlimited/Corbis

Cleistothecia on leaf tissue

Conidia on leaf tissue

George

Barron

https://atrium.lib.uoguelph.ca/xmlui/handl

e/10214/5710

Morels (Morchella),

grow in woodlands

and are often

associated with trees

such as oaks.

http://img1.nymag.com/content/dam/slideshows/2

012/11/truffle-hunting/pig-truffle-hunting.jpg

Truffles (Tuber)

Ascomycota- sac fungi

http://microbeonline.com/wp-

content/uploads/2014/10/LPCB-Mount-and-Aspergillus.jpg yeast

Saccharomyces

cerevisiae

Pseudogymnoascus

destructans

http://news.bbcimg.co.uk/media/images/

56289000/jpg/_56289201_56288947.jpg

http://www.bbc.com/news/science-environment-23599983

Bat with white-nose syndrome

Basidiomycota- club fungi

The name club fungi is derived from the fact that spores are produced at the ends of club-like structures (basidia).

Basidiomycota- club fungi

http://fsi.colostate.edu/wp-content/uploads/2014/07/mushrooms.png

Basidiomycota- club fungi

Lichens are partnerships between fungi and photosynthetic microbes.

http://justinsomnia.org/images/corn-smut-aka-huitlacoche-big.jpg Corn smut (Ustilago)

-Lichen bodies are masses of fungal hyphae with layers of autotrophic (photosynthetic) green algae or cyanobacteria

-The algae provide the lichen fungi (mycobiont) with organic food and oxygen.

-The fungi provide the autotroph (photobiont) with carbon dioxide from respiration, water, minerals, and protection.

Lichens body types

Study questions for Chapter 20-Fungi and Lichens

What does mycota mean?

List 3 characteristics of fungi.

Define hyphae.

Define mycelium.

Define fruiting body.

Define rhizomorph.

Label the different fungal bodies below using the terms below:

-single cells

-organized fruiting bodies

-unorganized fruiting bodies

Using the image provided, explain how fungal hyphae get nutrition.

Name the 5 fungal phyla.

Which phyla are included in the coenomycetes (lower fungi)?

Which phyla are included in the dikaryomycetes (higher fungi)?

What are the characteristics that distinguish the higher fungi from the lower fungi?

yeast

Penicillium

corn smut

chytrid (arrows)

Aspergillus

morel

bracket fungi

Study questions for Chapter 20-Fungi and Lichens

Define dikaryotic life cycle.

Define plasmogamy.

Define karyogamy.

Chytridiomycota

Define chytrid.

What chytrid is responsible for the decline of amphibian species worldwide?

What are some symptoms of the chytrid infection?

Zygomycota

Define thick-walled zygospore.

What is the genus of black bread mold?

Name the life cycle in black bread mold.

Glomeromycota

Define arbuscle.

What does AM fungi stand for?

What is an endomycorrhizae?

Why are the Glomeromycota important in the evolution of early plants from water to land?

Ascomycota

Define asci.

Define ascocarp.

What the 3 types of ascocarps in the Ascomycota? Give an example for each.

What fungal disease is wiping out several species of bats in North America?

Basidiomycota

Define basidium (basidia).

Define basidiospores.

Give examples of fungi in the Basidiomycota.

Define lichen.

Define mycobiont.

Define phycobiont.

Draw and label the 3 lichen body types.

Study questions for Chapter 20-Fungi and Lichens Three characteristics for each fungal phylum.

Glomeromycota

Ascomycota

Chytridiomycota Zygomycota

Basidiomycota