Daimler AG on Tuesday said it would expand its cooperation with partner Nissan Motor Co Ltd to develop a mid-sized pickup truck for Mercedes-Benz as the German premium automaker seeks to narrow its sales gap with rival BMW. The new Mercedes-Benz pickup targets commercial and private clients in Europe, Latin America, Australia and South Africa, and will share some of the underpinnings with an all-new Nissan NP300 truck, Daimler and Nissan said in a joint statement.