[Objective] The gen A inactive mutant was constructed on the basis of Micromonospora purpurea G1008,and then the function of gen A was studied by analyzing the secondary metabolites.[Methods] Plasmid p AB103 used for the gen A in-frame deletion was constructed and transformed into Micromonospora purpurea G1008 by conjugation.Apramycin resistance and PCR amplification were used to confirm Micromonospora purpurea GA1048.[Results] Gentamicin A2,instead of gentamicin C complex,was accumulated in Micromonospora ...