Has an artificial symbiotic relationship ever been created?

Question

Have 2 organisms ever been introduced to create a symbiotic relationship that doesn't occur in their natural environment?

Answer 1

The only one that I can think of is the relationship between dogs and humans. Humans get emotion support from dogs while dogs receive food and shelter.

Answer 2

It depends on your definition of "natural environment," but I would think that any pet-owner relationship would be symbiotic, as would be the bee-keeper relationship.