title: Regulation of pentose utilisation by AraR, but not XlnR, differs in Aspergillus nidulans and Aspergillus niger.
abstract: Filamentous fungi are important producers of plant polysaccharide degrading enzymes that are used in many industrial applications. These enzymes are produced by the fungus to liberate monomeric sugars that are used as carbon source. Two of the main components of plant polysaccharides are L-arabinose and D-xylose, which are metabolized through the pentose catabolic pathway (PCP) in these fungi. In Aspergillus niger, the regulation of pentose release from polysaccharides and the PCP involves the transcriptional activators AraR and XlnR, which are also present in other Aspergilli such as Aspergillus nidulans. The comparative analysis revealed that the regulation of the PCP by AraR differs in A. nidulans and A. niger, whereas the regulation of the PCP by XlnR was similar in both species. This was demonstrated by the growth differences on L-arabinose between disruptant strains for araR and xlnR in A. nidulans and A. niger. In addition, the expression profiles of genes encoding L-arabinose reductase (larA), L-arabitol dehydrogenase (ladA) and xylitol dehydrogenase (xdhA) differed in these strains. This data suggests evolutionary changes in these two species that affect pentose utilisation. This study also implies that manipulating regulatory systems to improve the production of polysaccharide degrading enzymes, may give different results in different industrial fungi.
authors.affiliation: Department of Microbiology and Kluyver Centre for Genomics of Industrial Fermentation, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: Evy
authors.initials: E
authors.lastname: Battaglia
authors.forename: Sara Fasmer
authors.initials: SF
authors.lastname: Hansen
authors.forename: Anne
authors.initials: A
authors.lastname: Leendertse
authors.forename: Susan
authors.initials: S
authors.lastname: Madrid
authors.forename: Harm
authors.initials: H
authors.lastname: Mulder
authors.forename: Igor
authors.initials: I
authors.lastname: Nikolaev
authors.forename: Ronald P
authors.initials: RP
authors.lastname: de Vries
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D007218:Industrial Microbiology; D008969:Molecular Sequence Data; D010429:Pentoses / Q000378:metabolism*; D016415:Sequence Alignment; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D010429:Pentoses; D015534:Trans-Activators; C115443:XlnR protein, Aspergillus