<jats:title>ABSTRACT</jats:title><jats:p>Detailed mechanisms of<jats:underline>W</jats:underline>hi<jats:underline>B</jats:underline>-<jats:underline>l</jats:underline>ike (Wbl) proteins involved in antibiotic biosynthesis and morphological differentiation are poorly understood. Here, we characterize the role of WblA<jats:sub>ch</jats:sub>, a<jats:named-content content-type="genus-species">Streptomyces chattanoogensis</jats:named-content>L10 protein belonging to this superfamily. Based on DNA microarray data and verified by real-time quantitative PCR (qRT-PCR), the expression of<jats:italic>wblA<jats:sub>ch</jats:sub></jats:italic>was shown to be positively regulated by AdpA<jats:sub>ch</jats:sub>. Gel retardation assays and DNase I footprinting experiments showed that AdpA<jats:sub>ch</jats:sub>has specific DNA-binding activity for the promoter region of<jats:italic>wblA<jats:sub>ch</jats:sub></jats:italic>. Gene disruption and genetic complementation revealed that WblA<jats:sub>ch</jats:sub>acts in a positive manner to regulate natamycin production. When<jats:italic>wblA<jats:sub>ch</jats:sub></jats:italic>was overexpressed in the wild-type strain, the natamycin yield was increased by ∼30%. This provides a strategy to generate improved strains for natamycin production. Moreover, transcriptional analysis showed that the expression levels of<jats:italic>whi</jats:italic>genes (including<jats:italic>whiA</jats:italic>,<jats:italic>whiB</jats:italic>,<jats:italic>whiH</jats:italic>, and<jats:italic>whiI</jats:italic>) were severely depressed in the Δ<jats:italic>wblA<jats:sub>ch</jats:sub></jats:italic>mutant, suggesting that WblA<jats:sub>ch</jats:sub>plays a part in morphological differentiation by influencing the expression of the<jats:italic>whi</jats:italic>genes.