ARA1 regulates not only L-arabinose but also D-galactose catabolism in Trichoderma reesei

Trichoderma reesei is used to produce saccharifying enzyme cocktails for biofuels. There is limited understanding of the transcription factors (TFs) that regulate the release and catabolism of L-arabinose and D-galactose, as the main TF XYR1 is only partially involved. The T. reesei ortholog of ARA1 from Pyricularia oryzae that regulates L-arabinose release and catabolism, was deleted and characterized by growth profiling and transcriptomics along with a xyr1 mutant and xyr1/ara1 double mutant. Our results show that, in addition to the L-arabinose-related role, T. reesei ARA1 is essential for D-galactose release and catabolism, while XYR1 is not involved in this process. Overall design: In this study, we aim to identify the target genes of the arabinanolytic transcription factor ARA1 in the Ascomycetes Trichoderma reesei while growing on the monosaccharides L-arabinose and D-galactose through transcriptome analysis. We compare the transcriptomes of the reference strain QM9414 with three deletion strains: hemicellulytic regulator XYR1, ARA1 and the double deletion XYR1ARA1 after 2h of growth in the different carbon sources.