Carbon catabolite repression (CCR) mediated by CRE1 in Trichoderma reesei emerged as a mechanism by
which the fungus could adapt to new environments. In the presence of readily available carbon sources such as glucose,
the fungus activates this mechanism and inhibits the production of cellulolytic complex enzymes to avoid unnecessary
energy expenditure. CCR has been well described for the growth of T. reesei in cellulose and glucose, however, little is
known about this process when the carbon source is sophorose, one of the most potent inducers of cellulase production.
Thus, we performed high-throughput RNA sequencing to better understand CCR during cellulase formation in the
presence of sophorose, by comparing the mutant cre1 with its parental strain, QM9414. Of the 9129 genes present in the
genome of T. reesei, 184 were upregulated and 344 downregulated in the mutant strain Δcre1 compared to QM9414.
Genes belonging to the CAZy database, and those encoding transcription factors and transporters are among the gene
classes that were repressed by CRE1 in the presence of sophorose; most were possible indirectly regulated by CRE1. We
also observed that CRE1 activity is carbon-dependent. A recent study from our group showed that in cellulose, CRE1
repress different groups of genes when compared to sophorose. CCR differences between these carbon sources may be
due to the release of cellodextrins in the cellulose polymer, resulting in different targets of CRE1 in both carbon sources.
These results contribute to a better understanding of CRE1-mediated CCR in T. reesei when glucose comes from a potent
inducer of cellulase production such as sophorose, which could prove useful in improving cellulase production by the