Some kinds of fungi form cooperative relationships with plants. The plants give the fungus sugars and the fungus gives the plants nutrients and water. They benefit each other. Sometimes plants give up to 1/3 of the sugars that they produce to the fungus. Voluntarily. Somewhere around 95% of all plants in the world are capable of forming these kinds of relationships with fungi. If you want to help a plant grow, this is something to look into.