Aspergillus niger RhaR, a regulator involved in L-rhamnose release and catabolism
article
The genome of the filamentous fungus Aspergillus niger is rich in genes encoding pectinases, a broad class of enzymes that have been extensively studied due to their use in industrial applications. The sequencing of the A. niger genome provided more knowledge concerning the individual pectinolytic genes, but little is known about the regulatory genes involved in pectin degradation. Understanding regulation of the pectinolytic genes provides a tool to optimize the production of pectinases in this industrially important fungus. This study describes the identification and characterization of one of the activators of pectinase-encoding genes, RhaR. Inactivation of the gene encoding this regulator resulted in down-regulation of genes involved in the release of L-rhamnose from the pectin substructure rhamnogalacturonan I, as well as catabolism of this monosaccharide. The rhaR disruptant was unable to grow on L-rhamnose, but only a small reduction in growth on pectin was observed. This is likely caused by the presence of a second, so far unknown regulator that responds to the presence of D-galacturonic acid. © 2014 Springer-Verlag. Chemicals/CAS: galacturonic acid, 14982-50-4, 685-73-4; pectin, 9000-69-5; pectin lyase, 9033-35-6; polygalacturonase, 9023-92-1, 9032-75-1; rhamnose, 10485-94-6, 3615-41-6
Topics
Aspergillus nigerL-rhamnose catabolismL-rhamnose releasePectin degradationTranscriptional regulationAspergillusEncoding (symbols)Industrial applicationsMetabolismDown-regulationFilamentous fungiL-rhamnoseRegulatory genesRhamnogalacturonan-ISmall reductionGene encodingGalacturonic acidPectinPectin lyasePolygalacturonaseRhamnoseBiodegradationCatabolismEnzyme activityGenomeGrowth rateAmino acid sequenceCarbohydrate metabolismCarbon sourceDNA flanking regionFungal geneFungal genomeFungal strainFungus cultureFungus growthGene expressionGene identificationGene inactivationMicroarray analysisMyceliumNonhumanOrthologyRegulator geneRhaR geneTranscription regulationFungi
TNO Identifier
513327
ISSN
14320614
Source
Applied Microbiology and Biotechnology, 98(12), pp. 5531-5540.
Pages
5531-5540
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