Nuclear traffic and cellulase production in Trichoderma

Trichoderma reesei (teleomorph Hypocrea jecorina) is the main industrial source of cellulases and hemicellulases used for the hydrolysis of biomass to simple sugars, which can then be converted to biofuels, such as ethanol, and other chemicals. The strains in use today have been obtained by classical mutagenesis. In order to learn how cellulase production was improved by these techniques, we previously used Illumina next generation sequencing technologies to identify mutations in the genomes of two hyperproducing mutants (NG14, and its direct improved descendant, RUT C30). Thereby, we detected several mutated genes that were mainly in nuclear transport, thus making nuclear traffic a potential pacemaker in cellulase production. In this project, we plan a systematic study on the importins and exportins responsible for nuclear traffic of the main cellulase regulator XYR1, and propose a strategy aimed at testing which of these components is actually rate limiting to cellulase gene expression.

Trichoderma reesei , a filamentous fungus, is the major industrial production of plant cell wall degrading enzymes which are applied in the pulp and paper, food and textile industries, as well as for the conversion of plant biomass materials into bioethanolor platform chemicals. The production of these cellulases adaptive and regulated by the action of several transcriptional activators of which XYR1 plays a major role. To perform its regulatory action, it has to enter the nucleus of the cell where DNA transcription occurs. This nucleus is surrounded by a double membrane, and proteins usually require active transport with the help of specific carriers. In our project, we have for the first time identified the carrier (KAP8) that is essential for the entry of XYR1 into the nucleus and formation of cellulases. This information will be of value for both further scientific work on cellulase formation as well as its improvement under industrial conditions.