Identification and transcriptional regulation of new starch modifying enzymes in the Aspergillus niger genome.

X. Yuan 1, R. Van der Kaaij 2, E. Martens 3, C.A.M.J.J. van den Hondel1,4, and A.F.J. Ram 1,4.

Author address: 

Leiden University, Institute of Biology Leiden, Fungal Genetics Research Group, Leiden, The Netherlands. 2University of Groningen, Microbial Physiology Research Group, Haren, The Netherlands. 3 W ageningen University, Section Fungal Genomics, W age

Abstract: 

Aspergillus niger is well known for its ability to secrete a wide variety of plant Carbohydrate Modifying Enzymes (CMEs). The secreted CMEs are able to degrade the plant cell wall materials as well as its storage carbohydrates, like starch. Based on its recently finished genomic sequence by Dutch life sciences company DSM , it is estimated that only a fraction of the potential of enzymes produced by A. niger is currently exploited. Database mining of the A.niger genome resulted in the identification of twelve new enzymes, which contain motifs indicating that they might act on starch. In addition to the known starch degrading enzymes of A.niger, glucoamylase (glaA), two alpha-amylase (amyA and amyB), an acid amylase (aamA) and an alpha-glucosidase (aglU), six putative alpha-amylases, five putative alpha-glucosidases and one alpha1,4-glucan branching enzyme were identified. It is well established that the expression of starch modifying enzymes is coordinately regulated at the transcriptional level by a pathway specific transcription factor AmyR. AmyR binds to sequences (CGGN 8 CGG or CGGN 8AGG) in the promoter region of amylolytic genes. Inspection of the promoter regions of the newly identified amylolytic genes revealed that only five of them contain AmyR consensus binding sites. The expression of the newly identified genes in relation to the presence of starch and the role of AmyR during regulation has been examined using microarrays and will be presented.
2005

abstract No: 

213.

Full conference title: 

23rd Fungal Genetics Conference
    • Fungal Genetics Conference 23rd (2002)