By using S.coelicolor as a model system,two dozen genes (bid and whi).most of them encoding regulatory proteins,important for initiation of aerial mycelium formation and sporulation have been identified [1].More than 20 other genes from primary metabolism and stress-response etc also affect Streptomyces differentiation,indicating that the regulatory signaling cascades for aerial growth and sporulation extensively interact with metabolic,morphological,homeostatic and stress-related checkpoints [2].