Characterization and engineering of new transcription factors involved in the stress response during cellulase production by Trichoderma reesei

Abstract

Lignocellulolytic enzymes are of fundamental importance in biofuel generation processes from plant biomass. The filamentous fungus Trichoderma reesei is a major producer of holocellulases, having one of the most intelligent cellulolytic systems. The gene expression of these enzymes is finely controlled by several transcription factors, which are used in genetic improvement strategies for this fungus to increase the production of cellulases. In addition, some studies demonstrate a relationship between osmotic stress and hypoxia and the production of cellulases, however little is known about this regulation at the transcriptional level. This project aims to characterize new transcription factors involved in the response to stress in T. reesei and its role in regulating cellulase production. For this, a set of transcription factors potentially involved in biomass degradation will be identified through in silico analysis of RNA-seq data and the homologues of Saccharomyces cerevisiae regulators related to the stress response will subsequently be deleted in T. reesei to verify their functions in cellulase production and stress response. The transcription factors will be fused to the GFP protein to assess its subcellular location and its interaction with DNA by chromatin immunoprecipitation. In addition, the most promising transcription factors will be engineered through fusion to the DNA binding domain from the repressor Cre1 to increase cellulase production. The data obtained will enable a better understanding of the behavior of cellulolytic enzymes produced by T. reesei, contributing to the construction of lines with greater production of cellulases. (AU)