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Zhang Y, Nada B, Baker SE, Evans JE, Tian C, Benz JP, Tamayo E. Unveiling a classical mutant in the context of the GH3 β-glucosidase family in Neurospora crassa. AMB Express 2024; 14:4. [PMID: 38180602 PMCID: PMC10770018 DOI: 10.1186/s13568-023-01658-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 12/23/2023] [Indexed: 01/06/2024] Open
Abstract
Classical fungal mutant strains obtained by mutagenesis have helped to elucidate fundamental metabolic pathways in the past. In the filamentous fungus Neurospora crassa, the gluc-1 strain was isolated long ago and characterized by its low level of β-glucosidase activity, which is essential for the degradation of cellulose, the most abundant biopolymer on Earth and the main polymeric component of the plant cell wall. Based on genomic resequencing, we hypothesized that the causative mutation resides in the β-glucosidase gene gh3-3 (bgl6, NCU08755). In this work, growth patterns, enzymatic activities and sugar utilization rates were analyzed in several mutant and overexpression strains related to gluc-1 and gh3-3. In addition, different mutants affected in the degradation and transport of cellobiose were analyzed. While overexpression of gh3-3 led to the recovery of β-glucosidase activity in the gluc-1 mutant, as well as normal utilization of cellobiose, the full gene deletion strain Δgh3-3 was found to behave differently than gluc-1 with lower secreted β-glucosidase activity, indicating a dominant role of the amino acid substitution in the point mutated gh3-3 gene of gluc-1. Our results furthermore confirm that GH3-3 is the major extracellular β-glucosidase in N. crassa and demonstrate that the two cellodextrin transporters CDT-1 and CDT-2 are essential for growth on cellobiose when the three main N. crassa β-glucosidases are absent. Overall, these findings provide valuable insight into the mechanisms of cellulose utilization in filamentous fungi, being an essential step in the efficient production of biorefinable sugars from agricultural and forestry plant biomass.
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Affiliation(s)
- Yuxin Zhang
- Fungal Biotechnology in Wood Science, Holzforschung München, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Basant Nada
- Fungal Biotechnology in Wood Science, Holzforschung München, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Scott E Baker
- DOE Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Microbial Molecular Phenotyping Group, Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - James E Evans
- Microbial Molecular Phenotyping Group, Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Chaoguang Tian
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - J Philipp Benz
- Fungal Biotechnology in Wood Science, Holzforschung München, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany
| | - Elisabeth Tamayo
- Fungal Biotechnology in Wood Science, Holzforschung München, TUM School of Life Sciences, Technical University of Munich, 85354, Freising, Germany.
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Zhang Y, Xu Z, Lu M, Ding B, Chen S, Wen Z, Yu Y, Zhou L, Jin M. Rapid evolution and mechanism elucidation for efficient cellobiose-utilizing Saccharomyces cerevisiae through Synthetic Chromosome Rearrangement and Modification by LoxPsym-mediated Evolution. Bioresour Technol 2022; 356:127268. [PMID: 35533888 DOI: 10.1016/j.biortech.2022.127268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 06/14/2023]
Abstract
Lack of cellobiose utilization capability for many microorganisms results in carbon source waste in lignocellulosic biorefinery. In this study, genes for cellobiose transport and hydrolysis were introduced to Saccharomyces cerevisiae synV, a semi-synthetic yeast with an inducible SCRaMbLE (Synthetic Chromosome Rearrangement and Modification by LoxPsym-mediated Evolution) system incorporated into its chromosome V, endowing cellobiose utilization capability to this strain. Thereafter, two evolved strains with 98.1% and 79.2% improvement, respectively, in cellobiose utilization rate were obtained through induced SCRaMbLE. Further studies suggested that the enhanced cellobiose utilization capability directly correlated with copy number increases of introduced genes and some chromosome structural variations. In particular, it was experimentally demonstrated for the first time that deletion of redox stress related gene MXR1 and ATP conversion related gene ADK2 contributed to enhanced cellobiose conversion. Thereafter, the effectiveness of MXR1 and ADK2 deletions was demonstrated in artificial hydrolysate and rice straw hydrolysate, respectively.
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Affiliation(s)
- Yuwei Zhang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Zhaoxian Xu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Minrui Lu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Boning Ding
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Sitong Chen
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Zhiqiang Wen
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, People's Republic of China
| | - Yang Yu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Linlin Zhou
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China; Biorefinery Research Institution, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China.
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