D-Xylose Concentration-Dependent Hydrolase Expression Profiles and the Function of CreA and XlnR in Aspergillus niger

A.R. Mach-Aigner, J. Omony, B. Jovanovic, A.J.B. van Boxtel, L.H. de Graaff

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33 Citations (Scopus)

Abstract

Aspergillus niger is an important organism for the production of industrial enzymes such as hemicellulases and pectinases. The xylan-backbone monomer, d-xylose, is an inducing substance for the coordinate expression of a large number of polysaccharide-degrading enzymes. In this study, the responses of 22 genes to low (1 mM) and high (50 mM) d-xylose concentrations were investigated. These 22 genes encode enzymes that function as xylan backbone-degrading enzymes, accessory enzymes, cellulose-degrading enzymes, or enzymes involved in the pentose catabolic pathway in A. niger. Notably, genes encoding enzymes that have a similar function (e.g., xylan backbone degradation) respond in a similar manner to different concentrations of d-xylose. Although low d-xylose concentrations provoke the greatest change in transcript levels, in particular, for hemicellulase-encoding genes, transcript formation in the presence of high concentrations of d-xylose was also observed. Interestingly, a high d-xylose concentration is favorable for certain groups of genes. Furthermore, the repressing influence of CreA on the transcription and transcript levels of a subset of these genes was observed regardless of whether a low or high concentration of d-xylose was used. Interestingly, the decrease in transcript levels of certain genes on high d-xylose concentrations is not reflected by the transcript level of their activator, XlnR. Regardless of the d-xylose concentration applied and whether CreA was functional, xlnR was constitutively expressed at a low level
Original languageEnglish
Pages (from-to)3145-3155
JournalApplied and Environmental Microbiology
Volume78
Issue number9
DOIs
Publication statusPublished - 2012

Keywords

  • transcriptional activator xlnr
  • jecorina trichoderma-reesei
  • cell-wall polysaccharides
  • time rt-pcr
  • hypocrea-jecorina
  • encoding genes
  • xylanase expression
  • beta-xylosidase
  • enzyme-system
  • l-arabitol

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