233 bp of promoter--PTH4 was subcloned into Streptomyces plasmid pIJ4083. pIJ4470 was obtained after recombinant plasmid was introduced into Streptomyces coelicolor J1501. Both Streptomyces coelicolor J1501/pIJ4083 and J1501/pIJ4470 were grown on minimal medium (MM) agar containing mannitol and 10 micrograms/mL thiostrepton for 6 days, and then ultrathin sections of colonies were prepared and stained with silver proteinate to observe glycogen biosynthesis in cell by the electron microscope. Result showed that the glycogen was produced by J1501/pIJ4083, whereas little glycogen was produced by J1501/pIJ4471. The dark color spores were not observed in J1501/pIJ4470 with lead stain in contrast with dark color spores which were produced by J1501/pIJ4083, indicating that promoter PTH4 may play an important role in physiological and morphological differentiation of Streptomyces.