Place fish in a shallow baking dish coated with cooking spray. Combine lemon juice and next 4 ingredients in a small bowl; pour over fish. Bake fish, uncovered, at 350° for 15 to 17 minutes or until fish flakes easily when tested with a fork. Set aside, and keep warm.
Coat a large saucepan with cooking spray; place over medium-high heat until hot. Add mushrooms, and saute until tender. Add rice and broth. Bring to a boil. Reduce heat, and simmer, uncovered, 5 minutes or until rice is tender and liquid is absorbed. To serve, transfer fish to serving plates using a slotted spoon, and spoon 1/2 cup rice mixture over each fillet.