Involved in unsaturated fatty acids biosynthesis. Catalyzes the dehydration of short chain beta-hydroxyacyl-ACPs and long chain saturated and unsaturated beta-hydroxyacyl-ACPs. a (3R)-hydroxyacyl-[ACP] = a (2E)-enoyl-[ACP] + H2O Oligomer. The N-terminus is blocked. Belongs to the thioester dehydratase family. FabZ subfamily.