A Novel Cys2His2 Zinc Finger Homolog of AZF1 Modulates Holocellulase Expression in Trichoderma reesei

• Published in: mSystems Vol. 4; no. 4
• Main Authors: Antonieto, Amanda Cristina Campos, Nogueira, Karoline Maria Vieira, de Paula, Renato Graciano, Nora, Luísa Czamanski, Cassiano, Murilo Henrique Anzolini, Guazzaroni, Maria-Eugenia, Almeida, Fausto, da Silva, Thiago Aparecido, Ries, Laure Nicolas Annick, de Assis, Leandro Jose, Goldman, Gustavo Henrique, Silva, Roberto Nascimento, Silva-Rocha, Rafael
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 18-06-2019
• Subjects: Bagasse; Biodegradation; Biomass; Carbon sources; Cell walls; Cellulase; Cellulose; Chromatin; Deoxyribonucleic acid; DNA; Enzymes; Fungi; Gene expression; Genes; Genetic engineering; Genomics; Glucose; Immunoprecipitation; Investigations; Lignocellulose; Molecular Biology and Physiology; Nutrient transport; Organisms; Polymers; Proteins; Regulatory sequences; Ribonucleic acid; RNA; Saccharomyces cerevisiae; Sugar; Sugarcane; Transcription factors; Trichoderma reesei; Zinc finger proteins; Brazil; systems biology; cis-regulatory elements; regulatory networks; holocellulase expression
• ISSN: 2379-5077; 2379-5077
• DOI: 10.1128/mSystems.00161-19

Filamentous fungi are remarkable producers of enzymes dedicated to the degradation of sugar polymers found in the plant cell wall. Here, we integrated transcriptomic data to identify novel transcription factors (TFs) related to the control of gene expression of lignocellulosic hydrolases in
and
Using various sets of differentially expressed genes, we identified some putative
-regulatory elements that were related to known binding sites for
TFs. Comparative genomics allowed the identification of six transcriptional factors in filamentous fungi that have corresponding
homologs. Additionally, a knockout strain of
lacking one of these TFs (
homolog) displayed strong reductions in the levels of expression of several cellulase-encoding genes in response to both Avicel and sugarcane bagasse, revealing a new player in the complex regulatory network operating in filamentous fungi during plant biomass degradation. Finally, RNA sequencing (RNA-seq) analysis showed the scope of the AZF1 homologue in regulating a number of processes in
, and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) provided evidence for the direct interaction of this TF in the promoter regions of
,
, and
Therefore, we identified here a novel TF which plays a positive effect in the expression of cellulase-encoding genes in
In this work, we used a systems biology approach to map new regulatory interactions in
controlling the expression of genes encoding cellulase and hemicellulase. By integrating transcriptomics related to complex biomass degradation, we were able to identify a novel transcriptional regulator which is able to activate the expression of these genes in response to two different cellulose sources.
experimental validation confirmed the role of this new regulator in several other processes related to carbon source utilization and nutrient transport. Therefore, this work revealed novel forms of regulatory interaction in this model system for plant biomass deconstruction and also represented a new approach that could be easy applied to other organisms.