Heat sesame oil in a large nonstick skillet over high heat. Add mushrooms and next 4 ingredients; stir-fry until tender. Add cooked rice; stir-fry 2 minutes. Push rice mixture to sides of pan, forming a well in center. Add egg to center of pan, and let cook 30 seconds; toss with rice, and stir-fry until egg is cooked. Stir in soy sauce and remaining ingredients; cook until thoroughly heated.