Preheat the oven to 350 degrees F. Coat a rimmed, foil lined baking sheet with non-stick cooking spray. Place fillets on baking sheet.
Melt half of the butter, brush over the rainbow trout. In a small bowl combine the panko, pecans, garlic salt and 1/2 teaspoon Italian seasoning. Mix to combine, and evenly distribute the mixture over the rainbow trout fillets.
Bake the rainbow trout for about 25 minutes, or until it flakes easily with a fork.
Meanwhile, heat the grapeseed oil in a skillet over medium heat. Stir in the mushrooms lightly saute for about 3 minutes. Stir in the artichoke hearts, remaining 1/2 teaspoon Italian seasoning, and pepper. Continue to cook and stir for about 6 minutes, then stir in the white wine. Allow the wine to simmer and reduce by half, about 10 minutes.
Stir in the fire roasted bell pepper, cook and stir until the peppers are warmed through. Stir in the remaining butter until it melts. Serve the sauce over the cooked trout.