Synthesis of xylanolytic enzymes and other carbohydrases by the fungus Penicillium canescens: Transformants with an altered copy number of the gene xlnR and an encoding transcriptional activator

A fragment of Penicillium canescens genomic DNA carrying the xlnR gene coding for a translational activator of xylanolytic genes was isolated. It was demonstrated that a loss of this function in genetically modified transformants resulted in a drastic decrease in the production of P. canescens major xylanases and had a negative effect on the syntheses of several other extracellular xylanases. An increase in the dose of the xlnR gene elevated the xylanolytic activity as well as the activities of a number of other auxiliary enzymes involved in xylan degradation. The activities of two P. canescens major secreted enzymes—β-galactosidase and α-L-arabinofuranosidase—appeared weakly dependent on the translational activator xlnR.