Combine mushrooms and soy sauce. Mix well.

Place mushroom mixture in covered nonreactive shallow pan or sealable plastic bag. Refrigerate 2 hours or overnight, turning twice while marinating.

Drain mushrooms. Discard marinade.

In stockpot over medium-high heat, heat oil. Add the marinated mushrooms. Sauté until browned, 5 to 7 minutes.

Add green pepper, onion and corn. Sauté 5 minutes.

For 1 taco, layer 1/2 cup of vegetable mixture on 1 tortilla and top with 1 Tbsp of Pico de Gallo, and 1 tsp of cilantro.