The fungus Aspergillus niger consumes sugars in a sequential manner that is not mediated by the carbon catabolite repressor CreA

Aspergillus niger is a filamentous ascomycete fungus that is commonly found in most biotopes around the globe. In nature, A. niger degrades the plant biomass polysaccharides to monomeric sugars, transports them into the cells, and uses a variety of catabolic pathways to convert them into biochemical building blocks and energy. We show that when grown in liquid cultures, A. niger takes up plant-biomass derived monomeric sugars (and maltose) in a highly sequential manner, rather than simultaneously. Interestingly, this sequential uptake was not mediated by the fungal general carbon catabolite repressor protein CreA, which has been shown to mediate the use of preferential carbon sources over non-preferential carbon sources. Furthermore, transcriptome analysis strongly indicated that the preferential use of the monomeric sugars is arranged at the level of transport, but it is not reflected in transcriptional regulation of sugar catabolism. Therefore, the results indicate that the regulation of sugar transport and catabolism are separate physiological processes in A. niger. We aim to understand the response of A. niger while growing on a mixture of monomeric sugars as carbon source. Biological duplicates were grown and sampled at different time points (12, 18, 24, 33 hours), Affimetrix microarray experiments were performed on these samples.