1. FUNGI
Federoff

2. The Characteristics of Fungi
Grow best in warm, moist environments
Mycology is the study of fungi
Mycologists study fungi
A fungicide is a chemical used to kill fungi
Fungicide kills leaf fungus

3. The Characteristics of Fungi
Fungi include puffballs, yeasts, mushrooms, toadstools, rusts, smuts, ringworm, and molds
The antibiotic penicillin is made by the Penicillium mold
Penicillium mold
Puffball

4. What Are Fungi?
Many fungi feed by absorbing nutrients from decaying matter in the soil. Others live as parasites, absorbing nutrients from their hosts.

5. What Are Fungi?
The cell walls of fungi are composed of chitin, a polymer made of modified sugars that is also found in the external skeletons of insects.
The presence of chitin is one of several features that show fungi are more closely related to animals than to plants.

6. Structure and Function
Yeasts are tiny fungi that live most of their lives as single cells.
Mushrooms and other fungi, on the other hand, grow much larger. Their bodies are made up of cells that form long, slender branching filaments called hyphae.

7. Structure and Function
In most fungi, cross walls divide the hyphae into compartments resembling cells, each containing one or two nuclei. In the cross walls, there are openings through which cytoplasm and organelles can move.

8. Structure and Function
The body of a mushroom is actually the fruiting body, the reproductive structure of the fungus.
The fruiting body grows from the mycelium, the mass of branching hyphae below the soil. Clusters of mushrooms are often part of the same mycelium, which means they are part of the same organism.

9. Hyphal growth from spore
Germinating spore
Fungal mycelia can be huge, but they usually escape notice because they are subterranean.
One giant individual of Armillaria ostoyae in Oregon is 3.4 miles in diameter and covers 2,200 acres of forest,
It is at least 2,400 years old, and weighs hundreds of tons.
(Actually noone has seen this of this extent – but cultures have been taken from soil over that area and all isolates have been found to be the same individual)
Ten cubic centimeters of rich organic soil may have fungal hyphae with a surface area of over 300 cm2
mycelium
Mycelia have a huge surface area
More surface area aids digestion & absorption of food

10. Structure and Function
The mycelium of the soil fungus in a fairy ring has grown so large that it has used up all of the nutrients near its center.
It grows and produces fruiting bodies—the mushrooms—only at its edges, where it comes in contact with fresh soil and abundant nutrients.

11. Reproduction
Fungi can reproduce asexually, primarily by releasing spores that are adapted to travel through air and water.
Breaking off a hypha or budding off a cell can also serve as asexual reproduction.

12. Reproduction
Most fungi can also reproduce sexually. The life cycle of the bread mold Rhizopus stolonifer is shown.

13. Reproduction
Sexual reproduction in fungi often involves two different mating types. One mating type is called “+” (plus) and the other “–” (minus).
Hyphae of opposite mating types fuse together, bringing + and – nuclei together in the same cell.

14. Reproduction
The + and – nuclei form pairs that divide as the mycelium grows. Many of the paired nuclei fuse to form diploid zygotes within a zygospore.

15. Reproduction The zygospore germinates and a sporangium emerges.
The sporangium reproduces asexually, releasing haploid spores produced by meiosis.
Each spore has a different combination of parental genes, and each can make a new mycelium.

16. Diversity of Fungi
More than 100,000 species of fungi are known. Biologists have placed fungi into several distinct groups.
The major groups of fungi differ from one another in their reproductive structures.

17. Decomposition
Many fungi feed by releasing digestive enzymes that break down leaves, fruit, and other organic material into simple molecules. These molecules then diffuse into the fungus.
Many organisms remove important trace elements and nutrients from the soil. Fungi recycle these essential elements and nutrients. If these materials were not returned, the soil would quickly be depleted.

18. ABSORPTIVE HETEROTROPH
Fungi get carbon from organic sources
Tips of Hyphae release enzymes
Enzymatic breakdown of substrate
Products diffuse back into hyphae
Nucleus “directs” the digestive process
Enzymatic breakdown
Most enzyme release (and absorption) at tips
Proteins and other materials synthesized by the entire mycelium are channeled by cytoplasmic streaming to the tips of the extending hyphae.
Enzymes
Digested material is then used by the hypha

19. Parasitism
Parasitic fungi can cause serious diseases in plants and animals by disrupting homeostasis.

20. Plant Diseases
A number of parasitic fungi cause diseases that threaten food crops. Corn smut, for example, destroys corn kernels.
Some mildews, which infect a wide variety of plants, are also fungi.

21. Animal Diseases Parasitic fungi can also infect humans.
The fungus that causes athlete’s foot forms a mycelium in the outer layers of the skin, which produces a red, inflamed sore from which the spores can easily spread from person to person.
The yeast Candida albicans is often responsible for vaginal yeast infections and for infections of the mouth called thrush.
Fungal diseases also affect insects, frogs, and mammals.
For example, the Cordyceps fungus infects grasshoppers in rain forests in Costa Rica. Microscopic spores become lodged in the grasshopper, where they germinate and produce enzymes that slowly penetrate the insect’s external skeleton. The spores multiply in the insect’s body, digesting all its cells and tissues until the insect dies.
Hyphae develop, cloaking the decaying exoskeleton in a web of fungal material. Reproductive structures, which will produce more spores and spread the infection, then emerge from the grasshopper’s remains.

22. Lichens
A lichen is a symbiotic association between a fungus and a photosynthetic organism. The photosynthetic organism is either a green alga or a cyanobacterium, or both.

23. Lichens
Lichens are extremely resistant to drought and cold. Therefore, they can grow in places where few other organisms can survive—on dry bare rock in deserts and on the tops of mountains.
Lichens are able to survive in these harsh environments because the green algae or cyanobacteria carry out photosynthesis, providing the fungus with a source of energy, while the fungus provides the green algae or cyanobacteria with water and minerals.
The densely packed hyphae protect the delicate green cells from intense sunlight.

24. Lichens
Lichens are often the first organisms to enter barren environments, gradually breaking down the rocks on which they grow. In this way, lichens help in the early stages of soil formation.
Lichens are also remarkably sensitive to air pollution: They are among the first organisms to be affected when air quality deteriorates.

25. Mycorrhizae
Fungi also form mutualistic relationships with plant roots. These symbiotic associations of plant roots and fungi are called mycorrhizae.
Researchers estimate that 80 to 90 percent of all plant species form mycorrhizae with fungi.
The hyphae collect water and minerals and bring them to the roots, greatly increasing the effective surface area of the root system. In addition, the fungi release enzymes that free nutrients in the soil.
The plants, in turn, provide the fungi with the products of photosynthesis.
The presence of mycorrhizae is essential for the growth of many plants. The seeds of orchids, for example, cannot germinate in the absence of mycorrhizal fungi. Many trees are unable to survive without fungal symbionts.

26. Mycorrhizae
This graph illustrates the growth rates of three species of trees with and without mycorrhizae.
The roots of plants are plugged into mycorrhizal networks that connect many plants.
In an experiment using isotopes to trace the movement of carbon, ecologist Suzanne Simard found that mycorrhizal fungi transferred carbon from paper birch trees growing in the sun to Douglas fir trees growing in the shade nearby.
As a result, the sun-starved fir trees thrived, basically by being “fed” carbon from the birches.
Simard’s findings suggest that plants—and their associated fungi—may be evolving as part of an ecological partnership.

27. MAJOR GROUPS OF FUNGI Basidiomycota – Club Fungi
Zygomycota – Bread Molds
Chytridiomycota – Chytrids
AM Fungi - Mycorrhizas
Ascomycota – Sac Fungi
Lichens – Symbiosis (algae & Fungi)

28. ZYGOMYCOTA

29. Rhizopus on strawberries
Zygomycota
Rhizopus on strawberries
Called the sporangium fungi
Commonly called molds
Hyphae have no cross walls (aseptate)
Grow rapidly
Form mycorrhizas
Includes bread mold
Tomato Blight
Most of the 600 zygomycote, or zygote fungi, are terrestrial, living in soil or on decaying plant and animal material.
Asexual reproduction in sporangia
One zygomycote group form mycorrhizas, mutualistic associations with the roots of plants.

30. BASIDIOMYCOTA

31. USES For Basidiomycota
Some are used as food (mushrooms)
Others damage crops (rusts & smuts)
Portobello Mushrooms
Soybean Rust
Corn Smut

32. ASCOMYCOTA

33. Characteristics Called Sac fungi
Very diverse includes Cup fungi, morels, truffles, yeasts, and mildew
May be plant parasites (Dutch elm disease and Chestnut blight)
Reproduce sexually & asexually
Specialized hyphae aid with reproduction
Mycologists have described over 60,000 species of ascomycetes, or sac fungi.
Ascomycota tend to grow from spore to spore in one year and relate well to living plant tissues
There is diverse form in the growth and fruiting structures – yeasts to morels, many intermediate (and small)
Asexual reproduction by conidia (externally produced, not in sporangia)
Half of the Ascomycota form lichens (evolved 8 or more times in different orders) but not all lichens are Ascomycotes

34. CHYTRIDIOMYCOTA

35. Chytridiomycota Called chytrids Produce motile spores
Mostly saprobes and parasites in aquatic habitats
Biodegrade and recycle nutrients
Classified in CMR as true fungi (because of their molecular relationships)
Remainder of the phyla are almost exclusively terrestrial (a few molds on wet plant material)
Chytrid that attacks Potatoes

36. MYCORRHIZA

37. MYCORRHIZAS Fungus associated with plant roots Mutualism between:
Fungus (nutrient & water uptake for plant)
Plant (carbohydrate for fungus)
Several kinds:
Zygomycota – hyphae invade root cells
Ascomycota & Basidiomycota – hyphae invade root but don’t penetrate cells
Extremely important ecologically
Half of the mushroom-forming fungi (basidiomycota) form mycorrhizas with trees
Some people think that the spongy tissue in roots evolved as a place where fungi could invade to form early links with plants that helped them survive the harsh life on early earth

38. LICHENS

39. LICHENS Mutualism between: Form a thallus (body) Fungus (structure)
Algae or cyanobacteria (provides food)
Form a thallus (body)
Foliose
Fruticose
Crustose
Thallus is a plant-like body that doesn’t have roots, stems or leaves
Thallus doesn’t look like either partner
Dual nature of thalli was not fully understood until early 1900’s
Fungus gives the name to the lichen (by agreement)
Fungus usually, but not always, an Ascomycote (in 8+ independent orders)
Algae green. If bluegreen bacteria present, lichens fix nitrogen (turn atmospheric nitrogen into amino acid nitrogen in proteins)