Preheat oven to 400°.
To prepare filling, lightly spoon 1/4 cup whole-wheat flour into a dry measuring cup, and level with a knife. Combine 1/4 cup whole-wheat flour and the next 4 ingredients (1/4 cup whole-wheat flour through juice) in a 13 x 9-inch baking dish coated with cooking spray. Let stand 10 minutes.
To prepare topping, lightly spoon all-purpose flour and 1/2 cup whole-wheat flour into dry measuring cups, and level with a knife. Combine the flours and next 4 ingredients (flours through salt) in a bowl; cut in butter with a pastry blender or 2 knives until mixture resembles coarse meal. Add buttermilk and rind, stirring just until moist. Drop dough onto fruit mixture to form 12 mounds; sprinkle with 2 teaspoons sugar.
Bake at 400° for 35 minutes or until bubbly. Let stand 10 minutes before serving.