Project description:Macrotermitine termites have domesticated fungi in the genus Termitomycesas their primary food source using predigested plant biomass. To access the full nutritional value of lignin-enriched plant biomass, the termite-fungus symbiosis requires the depolymerization of this complex phenolic polymer. While most previous work suggests that lignocellulose degradation is accomplished predominantly by the fungal cultivar, our current understanding of the underlying biomolecular mechanisms remains rudimentary. Here, we provide conclusive omics and activity-based evidence that Termitomyces employs not only a broad array of carbohydrate-active enzymes (CAZymes) but also a restricted set of oxidizing enzymes (manganese peroxidase, dye decolorization peroxidase, an unspecific peroxygenase, laccases, and aryl-alcohol oxidases) and Fenton chemistry for biomass degradation. We propose for the first time that Termitomyces induces hydroquinone-mediated Fenton chemistry using a herein newly described 2-methoxy-1,4-dihy-droxybenzene (2-MH2Q, compound 19)-based electron shuttle system to complement the enzymatic degradation pathways. This study provides a comprehensive depiction of how efficient biomass degradation by means of this ancient insect’s agricultural symbiosis is accomplished.
Project description:A microarray analysis to investigate transcriptional responses in the ectomycorrhizal fungus Paxillus involutus, after providing various sources of nitrogen. Five different sources of nitrogen representing various degrees of complexity were provided as patches in peat microcosms for fungal ingrowth: ammonium phosphate (APO), ammonium sulphate (ASU), glutamine (GLN), bovine serum albumin (BSA), and chitin (CHI). After fungal establishment of patches total RNA was isolated and used for global transcriptional analyses using cDNA microarrays. The entire design involved 9 slides (in the range DW2_01--DW2_13), 14 labelled extracts, and 3 biological replicates (R1-R3). The experiment was designed as a loop combining the 5 diffrent samples and including dye-swaps and biological replication. COMMENT: In our analysis of the raw dataset, 3 channels were removed due to poor signal quality: array 12707648b, Cy5 (635nm) channel (GLN R1 sample); array 12707650c, Cy5 (635nm) channel (APO R1 sample); array 12707651b, Cy5 (635nm) channel (APO R1 sample).