title: Deletion of pH Regulator pac-3 Affects Cellulase and Xylanase Activity during Sugarcane Bagasse Degradation by Neurospora crassa.
abstract: Microorganisms play a vital role in bioethanol production whose usage as fuel energy is increasing worldwide. The filamentous fungus Neurospora crassa synthesize and secrete the major enzymes involved in plant cell wall deconstruction. The production of cellulases and hemicellulases is known to be affected by the environmental pH; however, the regulatory mechanisms of this process are still poorly understood. In this study, we investigated the role of the pH regulator PAC-3 in N. crassa during their growth on sugarcane bagasse at different pH conditions. Our data indicate that secretion of cellulolytic enzymes is reduced in the mutant Δpac-3 at alkaline pH, whereas xylanases are positively regulated by PAC-3 in acidic (pH 5.0), neutral (pH 7.0), and alkaline (pH 10.0) medium. Gene expression profiles, evaluated by real-time qPCR, revealed that genes encoding cellulases and hemicellulases are also subject to PAC-3 control. Moreover, deletion of pac-3 affects the expression of transcription factor-encoding genes. Together, the results suggest that the regulation of holocellulase genes by PAC-3 can occur as directly as in indirect manner. Our study helps improve the understanding of holocellulolytic performance in response to PAC-3 and should thereby contribute to the better use of N. crassa in the biotechnology industry.
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Amanda Cristina
authors.initials: AC
authors.lastname: Campos Antoniêto
authors.affiliation: Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Wellington
authors.initials: W
authors.lastname: Ramos Pedersoli
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Lílian
authors.initials: L
authors.lastname: Dos Santos Castro
authors.affiliation: Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: da Silva Santos
authors.affiliation: Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Aline Helena da Silva
authors.initials: AH
authors.lastname: Cruz
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Karoline Maria Vieira
authors.initials: KM
authors.lastname: Nogueira
authors.affiliation: Systems and Synthetic Biology Laboratory, Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Silva-Rocha
authors.affiliation: Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rossi
authors.affiliation: Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Roberto Nascimento
authors.identifier: http://orcid.org/0000-0002-8992-7130
authors.initials: RN
authors.lastname: Silva
mesh_terms: D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005800:Genes, Fungal; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009492:Neurospora crassa / Q000201:enzymology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D031786:Saccharum / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D002482:Cellulose; C027433:bagasse; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases