Quantitative Proteome Profiling Reveals Cellobiose-Dependent Protein Processing and Export Pathways for the Lignocellulolytic Response in Neurospora crassa

Journal Article · Mon Jul 20 00:00:00 EDT 2020 · Applied and Environmental Microbiology

DOI:https://doi.org/10.1128/aem.00653-20· OSTI ID:1783110

Liu, Dan ^[1]; Liu, Yisong ^[1]; Zhang, Duoduo ^[1]; Chen, Xiaoting ^[1]; Liu, Qian ^[1]; Xiong, Bentao ^[1]; Zhang, Lihui ^[1]; Wei, Linfang ^[1]; Wang, Yifan ^[1]; Fang, Hao ^[1]; Liesche, Johannes ^[1]; Wei, Yahong ^[1]; Glass, N. Louise ^[2]; Hao, Zhiqi ^[3]; Chen, Shaolin ^[1]

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1. Northwest A&F University (China)
2. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
3. Thermo Fisher Scientific, San Jose, CA (United States)

Filamentous fungi are intensively used for producing industrial enzymes, including lignocellulases. Employing insoluble cellulose to induce the production of lignocellulases causes some drawbacks, e.g., a complex fermentation operation, which can be overcome by using soluble inducers such as cellobiose. Here, a triple β-glucosidase mutant of Neurospora crassa, which prevents rapid turnover of cellobiose and thus allows the disaccharide to induce lignocellulases, was applied to profile the proteome responses to cellobiose and cellulose (Avicel). Our results revealed a shared proteomic response to cellobiose and Avicel, whose elements included lignocellulases and cellulolytic product transporters. While the cellulolytic proteins showed a correlated increase in protein and mRNA levels, only a moderate correlation was observed on a proteomic scale between protein and mRNA levels (R² = 0.31). Ribosome biogenesis and rRNA processing were significantly overrepresented in the protein set with increased protein but unchanged mRNA abundances in response to Avicel. Ribosome biogenesis, as well as protein processing and protein export, was also enriched in the protein set that showed increased abundance in response to cellobiose. NCU05895, a homolog of yeast CWH43, is potentially involved in transferring a glycosylphosphatidylinositol (GPI) anchor to nascent proteins. This protein showed increased abundance but no significant change in mRNA levels. Disruption of CWH43 resulted in a significant decrease in cellulase activities and secreted protein levels in cultures grown on Avicel, suggesting a positive regulatory role for CWH43 in cellulase production. The findings should have an impact on a systems engineering approach for strain improvement for the production of lignocellulases.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1783110
• Journal Information: Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 15 Vol. 86; ISSN 0099-2240
• Publisher: American Society for Microbiology
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES