SCO3129, a TetR family regulator, is responsible for osmotic stress in .

are the soil-dwelling bacteria with a complex lifecycle and a considerable ability to produce a variety of secondary metabolites. Osmoregulation is important for their lifecycle in nature. In the genome of M145, (encodes a putative fatty acid desaturase), (encodes a putative TetR family regulator) and (encodes a putative l-carnitine dehydratase) constitute a transcriptional unit, and its transcript was found to be in response to osmotic stress. Disruption of led to a bald phenotype on MMG medium and the mycelia lysis on the edge of the colony when KCl/NaCl was added to the medium. These results indicated that SCO3130 is important for the osmotic stress resistance in . Transcriptional analysis and electrophoretic mobility shift assays (EMSA) demonstrated that SCO3129 repressed the transcription of operon through directly binding to the promoter region of , indicating that SCO3129 regulates the transcription of in response to osmotic stress.