Mediterranean Turkey Burgers

Serve a light and fresh turkey burger with pesto sauce and feta cheese. Hot, creamy tzatziki sauce is great to spread on burgers or serve as a side dish for dipping.
Combine the first 8 ingredients in a bowl; mix until smooth. Divide the panko mixture into 4 portions, forming each into a 1/2-inch-thick oval tortilla.Preheat a non-stick grill pan over medium-high heat. Brush the mold with cooking spray. Place the patties in the pan; cook for 6 minutes on each side or until tender. Add 1 patty and 1/2 cup arugula to each half of the pita bread.Tzatziki sauce: Combine 1/2 cup plain Greek-style low-fat yogurt, 1/4 cup finely chopped cucumber without seeds, 1/4 teaspoon salt, and 1/8 teaspoon ground red pepper. Serve with chopped bell pepper and celery sticks.