Mushrooms (= toadstools), mildew, molds, yeast & a few other things

#1) Hyphae; Mycelia (underground, can spread for acres)

The mushrooms, brackets etc. are spore-producing extensions.
" Fairy Rings " show the outer edges of large mycelia."

ONE) The most primitive are the chitrids
Among other things, chitrids cause disease in frogs, etc.

Both the male and the female gametes are flagellated & swim!

#3) TWO) Zygomycota ("Zygomycetes" ?)
Mating occurs by growing together of hyphae from nearby individuals having two different mating types

#4) THREE) Basidiomycetes basidiospores 4 spores

(most mushrooms are basidiomycetes)

FOUR) Ascomycetes ascospores
(Each ascus is a sack with 8 spores; (plural : "asci") products of a single meiotic division, followed by one mitosis; For some experiments: it can be a big help to have meiotic products together)

Many species are known to be one or the other, but you can't tell which
& these used to be called "Fungi Imperfecti" = Deuteromycetes .

Fungi participate in several very important kinds of mutualism (symbiotic relationships)

#6) Mycorrhizae

Ectomycorrhizal Fungi:
Connect to angiosperm and gymnosperm roots.
Absorb and transfer nutrients such as nitrogen to roots.
Needed by nearly all tree species in temperate or cold area.
At least half of mushroom-forming basidiomycetes do this.

Arbuscular Mycorrhizal Fungi :
Penetrate into the root cells
All are members of Zygomycota
In 80% of land plant species, esp. grasslands, tropical or warm

Symbiotic combination between fungi (mostly ascomycetes) and various kinds of algae (mostly Green Algae, but in some species Blue-Green Algae [procaryotes!] and in a few species Brown Algae. (There don't seem to be any red algae + fungi lichens)

#8) Many plant diseases are caused by different particular species of fungi. And also a few human diseases, like athletes foot, "ringworm", and yeast infections.

#9) Leaf and stem endophytes

Fungi that grow in and on leaves and stems.
Relatively newly discovered. (especially tropics?)
Are they parasites or symbiotes?
Some in grasses make toxins that harm insect herbivores!

Page 566: top: "Because they are tubes " (by which they actually mean cylinders!)
"they have the highest possible surface area to volume ratio."

Actually, cylinders have one of the lowest ratios of surface to volume!
If their cross-section were square, triangular, elliptical, etc. then the surface area/volume would be larger!

If they were spherical, instead of being elongate, then they could have a smaller surface area per volume; but for anything elongate, the cylindrical shape has the smallest surface area.

Always remember these golden words: "Make sure brain is turned on before thinking."

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Questions that might be on an exam

b) Mushrooms (and the equivalent "bracket fungi" that stick out of the sides of trees and logs) have what relationship to mycelia?

c) Why are mushrooms sometimes distributed as rings 10, 20 or 50 feet or so in diameter? (diameter of the rings, not the individual mushrooms, of course!)

d) What is the name of a group of fungi in which two kinds of gametes are produced, both of which swim by means of flagella (kind of like sperm), and fuse together to form a diploid phase of their cell cycle?

e) Members of this group of fungi cause serious infectious diseases in what class of vertebrates?

f) How does mating occur in the zygomycota?

g) If meiosis in a fungus produces spores in an elongate sack, usually with 8 spores, each such sack is called an ______, and that species of fungus is classified as belonging to the _______-mycetes?

h) Mushrooms serve what function?

i) Most mushrooms are produced by members of which of the sub-groups of the fungi?

j) What are yeasts?

*k) Members of the Deuteromycetes (that used to be called "Fungi Imperfecti") differ in what way from Basidiomycetes and Ascomycetes?

l) What is meant by mutualism, including another term for the same category of phenomenon?

m) Lichens consist of a combination of cells of some species of algae growing among cells of what?

n) Are the algae of lichens eucaryotic algae, or procaryote (blue-green) algae? (trick question)

o) Do Brown Algae participate in the formation of any kinds of lichens? (hint: yes, but only rarely)

p) Besides lichens, what is another important kind symbiotic relationship between some fungi and many (or most?!) species of seed plants?

q) Do some species of fungi cause diseases in flowering plants?
(hint: did you ever hear of the Potato Blight, that caused so many to starve to death in Ireland in the 1840s)

r) Are there any human diseases caused by fungi? Are there some such diseases caused by fungi that grow as mycelia? And others that grow in the morphology of yeast? (hint: yes)

*s) Can you figure out why there are fewer good antibiotics for treating fungal diseases than there are for treating bacterial diseases?
[NOTE: This is a conceptual question, relating to how antibiotics work, and also to evolutionary relationships of people to fungi and bacteria.]

t) Suppose that somebody developed a chemical that would kill all fungi, but not directly harm either angiosperms or gymnosperms: would it be a good idea to spray this chemical on fields and forests, to protect plants from fungal diseases. (hint: why not?)

*u) Although a few kinds of edible mushrooms can be deliberately grown, as a crop, often in caves or indoors, attempts to grow most species of mushrooms as a crop have (notoriously) failed, despite many attempts, and the prospect of millions of dollars for anyone who could succeed. Suggest at least one possible reason for this, based on what you have learned.

*v) What are some differences between arbuscular as compared with ectomycorrhizal fungi.

w) What is meant by "endophytic fungi"?