Fungi Relationships and Interactions

Beneficial Effects of Fungi
- Decomposition - nutrient and carbon recycling.
- Biosynthetic factories. Can be used to produce drugs, antibiotics, alcohol, acids, food (e.g., fermented products, mushrooms).
- Model organisms for biochemical and genetic studies.
Harmful Effects of Fungi
- Destruction of food, lumber, paper, and cloth.
- Animal and human diseases (mycosis), including allergies.
- Toxins produced by poisonous mushrooms and within food (e.g., grain, cheese, etc.).
- Plant diseases.

Ecosystems depend on fungi as decomposers and symbionts: they decompose food, wood and even plastics!
Some fungi are pathogens
- Plants particularly susceptible (e.g. Dutch elm disease)
- Ergot - affects cereal crops: causes gangrene, hallucinations and “St. Anthony’s fire”
Many animals, including humans, eat fungi:
- In US, mushroom consumption restricted to Agaricus
- We eat a range of cultivated and wild mushrooms
- Truffles are underground ascocarps of mycelia that are mycorrhizal on tree roots

Some fungi share their digestive services with animals
These fungi help break down plant material in the guts of cows and other grazing mammals
Many species of ants use the digestive power of fungi by raising them in “farms”

Mycorrhizae are enormously important in natural ecosystems and agriculture
Plants harbor harmless symbiotic endophytes
- Endophytes: fungi that live inside leaves or other plant parts
Endophytes make toxins that deter herbivores and defend against pathogens
Most endophytes are ascomycetes