What are mycorrhizial relationships? Provide an example.

Mycorrhizal associations are relationships between plant roots and associated fungi that grow on the roots. Because both the plant and the fungus benefits from the relationship, this is an example of a mutualistic relationship. In the Zygomycota, the fungus supplies the plant with phosphorus, while the fungus obtains necessary sugars from the plant. Basidiomycota also frequently form mycorrhizal associations, in which the plant obtains nitrogen from the fungus in return for sugars provided by the plant.