17-01: A genome-wide approach to understand the roots of cellulase hyper-secretion in the filamentous fungus Trichoderma reesei

The filamentous fungus Trichoderma reesei is well-known for its impressive capacity to secrete high amounts of cellulase and hemicellulase enzymes. These enzymes are key components of most cellulosic biomass to biofuel biological processes, and despite huge R&D efforts, their cost is still too high. Most industrial strains in use today have been obtained by random mutagenesis of the original QM6a isolate. Highest performances range from 40 to above 100 g/L proteins production, depending on the strain and process configuration used. While it is not known whether the already impressive performances of these strains can be further enhanced through targeted genetic engineering, there is still a high interest in understanding the genetic mechanisms leading to cellulase (hyper)secretion and to set up genomic tools that could be used to adapt strains to various industrial conditions. Toward this goal our group has been investigating the set-up of cellulase production both on the single-gene level (Portnoy et al., 2011a) and on the whole transcriptome level using dedicated DNA microarrays (Portnoy et al., 2011b). We are currently completing our previous high-throughput sequencing of the NG14 and RUT C30 strain lineage (Le Crom et al., 2009) with the sequencing of five other strains. These genome data are also being completed by transcriptome analysis. Our objective is to provide a whole picture of the mechanisms involved in cellulase production by T. reesei as well as potential new targets for genetic engineering of industrial strains.