Investigating the Molecular Crosstalk of Cellulose and Hemicellulose Perception in Filamentous Fungi

• Applicant: Professor Dr. J. Philipp Benz
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms ; Microbial Ecology and Applied Microbiology ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 391588914

Due to their role in biomass mineralization, fungi are indispensable for the global carbon cycle. In addition, filamentous fungi are of great economic importance as source of enzymes for the biorefinery. The production of plant cell wall degrading enzymes by fungi is finely tuned to the composition of the biomass. The basis for this are molecular signaling cascades leading to the perception of sugars liberated from the polysaccharides. However, the signaling pathways are still largely a black box to us, hampering the industrial strain improvement for enzyme, cellulosic fuel and chemical production by rational design. Biomass decomposition for biorefinery will highly benefit from an increased understanding of how fungi perceive and integrate the signals coming from the substrate and fine-tune their secreted enzymes to exactly fit the composition of the biomass at hand. In our attempts to elucidate plant cell wall perception in the filamentous Ascomycete Neurospora crassa, we have obtained evidence that not all sugars are perceived independently, but that some pathways overlap such that a reciprocal inhibition can occur, as is the case for cellulose and mannan signaling. Moreover, we found this crosstalk to be conserved in the industrially relevant species Trichoderma reesei and Myceliophthora thermophila. Since mannans are present in most lignocellulosic biomass and are very difficult to be selectively removed from cellulose and other hemicelluloses by chemical (pre-)treatments, the crosstalk has to be dealt with by other methods. A promising solution to this problem might be genetic engineering of the signaling pathways in the fungal production hosts. In the current application, we therefore propose a research program to elucidate the underlying mechanisms of this crosstalk in N. crassa, T. reesei and M. thermophila with the goal to relief them from this potential inhibition by genetic engineering and achieve unrestrained cellulase production. Moreover, the elucidation of the molecular mechanisms controlling these events will also strongly fasten future industrial fungal strain engineering efforts for the biorefinery.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partner: Professor Chaoguang Tian, Ph.D.