Comparative transcriptome analysis reveals different strategies for degradation of steam-exploded sugarcane bagasse by Aspergillus niger and Trichoderma reesei

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Borin, Gustavo Pagotto ; Sanchez, Camila Cristina ; de Santana, Eliane Silva ; Zanini, Guilherme Keppe ; Correa dos Santos, Renato Augusto ; Pontes, Angelica de Oliveira ; de Souza, Aline Tieppo ; Tavares Soares Dal'Mas, Roberta Maria Menegaldo ; Riano-Pachon, Diego Mauricio ; Goldman, Gustavo Henrique ; de Castro Oliveira, Juliana Velasco

• Tipo de documento: Artigo Científico
• Fonte: BMC Genomics; v. 18, JUN 30 2017.
• Citações Web of Science: 22

Resumo

Background: Second generation (2G) ethanol is produced by breaking down lignocellulosic biomass into fermentable sugars. In Brazil, sugarcane bagasse has been proposed as the lignocellulosic residue for this biofuel production. The enzymatic cocktails for the degradation of biomass-derived polysaccharides are mostly produced by fungi, such as Aspergillus niger and Trichoderma reesei. However, it is not yet fully understood how these microorganisms degrade plant biomass. In order to identify transcriptomic changes during steam-exploded bagasse (SEB) breakdown, we conducted a RNA-seq comparative transcriptome profiling of both fungi growing on SEB as carbon source. Results: Particular attention was focused on CAZymes, sugar transporters, transcription factors (TFs) and other proteins related to lignocellulose degradation. Although genes coding for the main enzymes involved in biomass deconstruction were expressed by both fungal strains since the beginning of the growth in SEB, significant differences were found in their expression profiles. The expression of these enzymes is mainly regulated at the transcription level, and A. niger and T. reesei also showed differences in TFs content and in their expression. Several sugar transporters that were induced in both fungal strains could be new players on biomass degradation besides their role in sugar uptake. Interestingly, our findings revealed that in both strains several genes that code for proteins of unknown function and pro-oxidant, antioxidant, and detoxification enzymes were induced during growth in SEB as carbon source, but their specific roles on lignocellulose degradation remain to be elucidated. Conclusions: This is the first report of a time-course experiment monitoring the degradation of pretreated bagasse by two important fungi using the RNA-seq technology. It was possible to identify a set of genes that might be applied in several biotechnology fields. The data suggest that these two microorganisms employ different strategies for biomass breakdown. This knowledge can be exploited for the rational design of enzymatic cocktails and 2G ethanol production improvement. (AU)

• Processo FAPESP: 15/08222-8 - Análise da co-regulação transcricional e identificação de genes de interesse biotecnológico em Trichoderma reesei
• Beneficiário: Gustavo Pagotto Borin
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 14/11733-1 - Caracterização de transportadores de Pseudozyma brasiliensis
• Beneficiário: Eliane Silva de Santana
• Linha de fomento: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 13/09541-4 - Estudos genômicos da expressão gênica global de Aspergillus niger crescido em bagaço e colmo de cana-de-açúcar
• Beneficiário: Camila Cristina Sanchez
• Linha de fomento: Bolsas no Brasil - Mestrado
• Processo FAPESP: 14/11766-7 - Caracterização de novos fatores de transcrição de Trichoderma reesei envolvidos na degradação da biomassa lignocelulósica
• Beneficiário: Juliana Velasco de Castro Oliveira
• Linha de fomento: Auxílio à Pesquisa - Programa BIOEN - Regular
• Processo FAPESP: 11/08945-9 - Estudos genômicos comparativos da expressão gênica global de fungos filamentosos crescidos em bagaço e colmo de cana-de-açúcar
• Beneficiário: Juliana Velasco de Castro Oliveira
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/15799-7 - Análise genômica da levedura xilanolítica Pseudozyma brasiliensis
• Beneficiário: Renato Augusto Corrêa dos Santos
• Linha de fomento: Bolsas no Brasil - Mestrado