Pleiotropic mutants of the wood-rotting fungus Polyporus adustus lacking cellulase, mannanase, and xylanase

By screening for mutants which could not degrade cellulose, several cellulase-less mutants were isolated from the wood-rotting fungus Polyporus adustus. Most of the mutants lacked mannanase and xylanase as well. In wild type, the level of cellulase, mannanase, and xylanase was higher when the fungus was grown in a medium containing cellulose than in a medium lacking cellulose. It is proposed that in P. adustus, the induction of this group of enzymes is under the control of a single common regulator gene.