Disruption of sabR affects nikkomycin biosynthesis and morphogenesis in Streptomyces ansochromogenes

The gene, sabR, encoding a receptor for γ-butyrolactone, was cloned from the genomic DNA of Streptomyces ansochromogenes 7100. Its deduced protein shows strong homology to several γ-butyrolactone-binding proteins in Streptomyces. Disruption of sabR retarded nikkomycin production in liquid media containing glucose or glycerol as carbon source. Sporulation of sabR disruption mutants was earlier than the parent strain on solid media with glucose or glycerol as carbon source. However, disruption of sabR had no effect on either nikkomycin production or sporulation on media containing mannitol as carbon source, suggesting that sabR is a pleiotropic regulatory gene that controls the onset of nikkomycin production and sporulation in S. ansochromogenes and is related to the utilization of carbon source.