Data from: The FlbA-regulated predicted transcription factor rpnR of Aspergillus niger is involved in stress resistance and protein secretion, in Regulators Controlled by the Sporulation Gene flbA of Aspergillus niger (Ph.D. thesis)

Proteins are secreted throughout the mycelium of Aspergillus niger except
for the sporulating zone. A link between sporulation and repression of
protein secretion was underlined by the finding that inactivation of the
sporulation gene flbA results in colonies that secrete proteins throughout
the colony. This finding is of interest to improve fungi as a cell
factory. However, ΔflbA hyphae also lyse and have thinner cell walls. This
pleiotropic phenotype is associated with differential expression of 36
transcription factor genes, of which rpnR was inactivated in this study.
Sporulation, biomass, and secretome complexity were not affected in strain
ΔrpnR. In contrast, ΔrpnR showed decreased resistance to H2O2 and the
proteotoxic stress-inducing agent dithiothreitol. This was associated with
reduced ribosomal subunit expression and reduced levels of proteins
secreted into the medium. Taken together, RpnR of A. niger is involved in
protein synthesis and proteotoxic stress resistance and is thus an
interesting target for improving enzyme production capacity.