Delignification abilities of the white-rot fungus Polyporus brumalis explained by its oxidative enzymatic arsenal
Ontology highlight
ABSTRACT:
ORGANISM(S): Polyporus brumalis
PROVIDER: GSE112011 | GEO | 2018/12/21
REPOSITORIES: GEO
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Project description:Delignification abilities of the white-rot fungus Polyporus brumalis explained by its oxidative enzymatic arsenal
| PRJNA438948 | ENA
Project description:We propose to elucidate new metabolic pathways in fungi - with a special focus on white rot fungi (WRF)- involved in the catabolism of lignin-derived aromatic compounds. Basidiomycete fungi, in particular WRF, are the most efficient organisms for the depolymerization and mineralization of lignin to CO2 and H2O in Nature and thus, WRF play a pivotal role in carbon cycling. Lignin depolymerization by WRF is mediated by the action of extracellular oxidative ligninolytic enzymes, such as laccases and peroxidases, alongside other secreted metabolites. This extracellular process has been studied for decades via analysis of lignin modifications, ligninolytic enzyme activity in fungal broths, enzyme isolation and characterization, and more recently through multi-omics analyses. Despite the massive research effort directed toward understanding how WRF depolymerize lignin, almost no attention has been dedicated to the elucidation of the intracellular metabolism of WRF in catabolizing lignin. In fact, whether or not WRF are able to catabolize lignin remains a matter of discussion and debate.
The work (proposal:https://doi.org/10.46936/10.25585/60001176) conducted by the U.S. Department of Energy Joint Genome Institute (https://ror.org/04xm1d337), a DOE Office of Science User Facility, is supported by the Office of Science of the U.S. Department of Energy operated under Contract No. DE-AC02-05CH11231.
2024-05-16 | MSV000094781 | MassIVE
Project description:The biodegradation of lignocellulose requires the disruption of its lignin, which shields the metabolically assimilable polysaccharides in this recalcitrant natural composite. Although a variety of microorganisms can attack lignocellulose, white rot basidiomycetes are uniquely efficient at this process, cleaving the recalcitrant intermonomer linkages of lignin via extracellular oxidative mechanisms and mineralizing many of the resulting fragments to carbon dioxide via intracellular processes. Considerable progress has been made in understanding this process in the model white rot fungus Phanerochaete chrysosporium, which expresses important components of its ligninolytic system in response to nutrient limitation, as part of its secondary metabolism. Biochemical and genetic evidence point to an important role in P. chrysosporium for secreted lignin peroxidases (LiPs), manganese peroxidases (MnPs), and H2O2-producing oxidases, which are thought to work together to cleave lignin into low molecular weight fragments. However, many aspects of ligninolysis by P. chrysosporium remain poorly understood. Although a definitive picture of the entire ligninolytic system in P. chrysosporium is not yet attainable, transcriptome analyses of the fungus grown on wood can provide useful clues. With the advent of the initial genome assembly and annotations (v1.0 and v2.1), microarray-based transcriptome analysis allowed examination of transcript levels of P. chrysosporium genes when grown in ball-milled wood and in defined growth media. This approach provided useful insights but was limited to 10048 v2.1 targets and complicated by the unpredictable manner in which the fungus responds to unnatural carbon sources in submerged basal salts media. A complete, fully coordinated ligninolytic system is likely not expressed by P. chrysosporium on ball-milled wood, because a potential route for regulatory feedback has been eliminated: the cellulose and hemicellulose in this substrate is readily accessible to enzymes, and thus ligninolysis is not essential for growth. An alternative approach is to compare levels of gene expression just before and after the onset of secondary metabolism and extracellular substrate oxidation by P. chrysosporium as it utilizes solid wood as its carbon source. If this can be done, and decay of the substrate is also confirmed, then the genes undergoing marked changes in expression during the metabolic transition can be identified with greater confidence. Although not all such genes are expected to have roles in biodegradation, this strategy may identify interesting candidates for future investigation. Here we report RNAseq-based transcriptomes to characterize changes in gene expression that occur during the transition to ligninolytic metabolism. Phanerochaete chrysosporium was inoculated onto thin sections of wood. RNA was purified from colonized material after 40 and 96 hours. Single read 100 bp Illumina runs were performed.
2015-09-16 | E-GEOD-69461 | biostudies-arrayexpress
Project description:The secretome of the white-rot fungus Bjerkandera adusta produced in synthetic Kirk medium was compared to that supplemented with an aqueous phenol-rich extract of olive mill residues (ADOR). Distinct changes in the protein composition of oxidoreductases, namely diverse class- II peroxidases and aryl alcohol oxidases were found. In the secretome produced in ADOR- supplemented medium (ASC) 157 different proteins were identified, whereas only 59 were secreted in cultures without ADOR supplementation (Kirk medium culture; KM). Peptide sequence analysis done by LC-MS turned out that the number of peroxidases produced in ASC was more than doubled (from 4 to 11) compared to KM. Two short manganese peroxidases (MnP1 & MnP6) and one versatile peroxidase (VP1) represented 29% of the relative abundance (NSAF) in ASC. Two of them (MnP1 & VP1) also detected in KM displayed a relative abundance (NSAF) of only 3%. Further peroxidases present in ASC were one lignin peroxidase (LiP2), one generic peroxidase (GP) and three dye-decolorizing peroxidases (DyPs). The relative abundance of DyPs and aryl alcohol oxidases (AAO) were lower in ASC in comparison to KM. In addition to peptide sequence analysis, the secretion of Mn2+-oxidizing peroxidases as well as AAOs were followed by enzyme measurement. The Mn2+-oxidizing activity increased nearly 30-fold (from 10 to 281 U l-1) after ADOR addition. Two enzymes responsible for that activity were successfully purified (BadVPI and BadVPII). To prove a potential involvement of these enzymes in the degradation of aromatic compounds, BadVPI was tested for its ability to degrade the recalcitrant dehydrogenated polymer (DHP, synthetic lignin). These results show that natural phenol-rich materials act as secretome-stimulating additives. Applying these substances enables us to investigate fungal degradation and detoxification processes and gives more insight into the complexity of fungal secretomes, e.g. of. white-rot fungi.
2018-02-28 | PXD000962 | Pride
Project description:Fungi are an important source of enzymes for saccharification of plant polysaccharides and production of biofuels. Understanding of the regulation and induction of expression of genes encoding these enzymes is still incomplete. To explore the induction mechanism, we analysed the response of the industrially important fungus Aspergillus niger to wheat straw, with a focus on events occurring shortly after exposure to the substrate. RNA sequencing showed that over a third of the genes induced after 6 h of exposure to wheat straw were also induced during 6 h of carbon starvation, indicating that carbon starvation is probably an important factor in the early response to wheat straw. The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides. Eight samples in total consisting of duplicate shake flask Aspergillus niger cultures from four conditions: 48h glucose, 6 h starvation, 6 h wheat straw, 24 h starvation
2014-08-22 | E-GEOD-57315 | biostudies-arrayexpress
Project description:To determine the wood degradation mechanism and its key genes of Lenzites gibbosa, we sequenced 15 transcriptomes of mycelial samples under woody environments at 3, 5, 7, and 11 d (D3, D5, D7, and D11) and non-woody environments (CK). All the transcripts were annotated as much as possible in eight databases to determine their function. The key genes and biological processes, relating to wood degradation, were predicted and screened. A total of 2069 differentially expressed genes (DEGs) were obtained in ten differential groups. Comparing wood with non-wood treatment conditions, the key genes were those participating in oxidation-reduction process, they were oxidoreductases and peroxidases genes, and their regulators genes; these genes mainly focused on the three biological processes of carbohydrate metabolism, lignin catabolism, and secondary metabolites biosynthesis, transport and catabolism. The mostly enriched subcategories in molecular function were oxidoreductase activity, peroxidase activity, and heme binding in GO annotation. One cellulose and hemicellulose degradation pathway and seven pathways related to lignin-derived aromatic compounds degradation or late lignin degradation were found. In conclusion, during the process of L. gibbosa growing on wood, gene expression at the transcriptional level indicated that lignin catabolism and hyphal growth were promoted, but the metabolism of carbon and carbohydrates including cellulose in lignocellulose in overall trend was inhibited to some extent. The results have important reference value for the study of degradation mechanism of wood white rot.
2023-09-17 | GSE184416 | GEO
Project description:Fungi are an important source of enzymes for saccharification of plant polysaccharides and production of biofuels. Understanding of the regulation and induction of expression of genes encoding these enzymes is still incomplete. To explore the induction mechanism, we analysed the response of the industrially important fungus Aspergillus niger to wheat straw, with a focus on events occurring shortly after exposure to the substrate. RNA sequencing showed that over a third of the genes induced after 6 h of exposure to wheat straw were also induced during 6 h of carbon starvation, indicating that carbon starvation is probably an important factor in the early response to wheat straw. The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides.
2014-08-22 | GSE57315 | GEO
Project description:The biodegradation of lignocellulose requires the disruption of its lignin, which shields the metabolically assimilable polysaccharides in this recalcitrant natural composite. Although a variety of microorganisms can attack lignocellulose, white rot basidiomycetes are uniquely efficient at this process, cleaving the recalcitrant intermonomer linkages of lignin via extracellular oxidative mechanisms and mineralizing many of the resulting fragments to carbon dioxide via intracellular processes. Considerable progress has been made in understanding this process in the model white rot fungus Phanerochaete chrysosporium, which expresses important components of its ligninolytic system in response to nutrient limitation, as part of its secondary metabolism. Biochemical and genetic evidence point to an important role in P. chrysosporium for secreted lignin peroxidases (LiPs), manganese peroxidases (MnPs), and H2O2-producing oxidases, which are thought to work together to cleave lignin into low molecular weight fragments. However, many aspects of ligninolysis by P. chrysosporium remain poorly understood. Although a definitive picture of the entire ligninolytic system in P. chrysosporium is not yet attainable, transcriptome analyses of the fungus grown on wood can provide useful clues. With the advent of the initial genome assembly and annotations (v1.0 and v2.1), microarray-based transcriptome analysis allowed examination of transcript levels of P. chrysosporium genes when grown in ball-milled wood and in defined growth media. This approach provided useful insights but was limited to 10048 v2.1 targets and complicated by the unpredictable manner in which the fungus responds to unnatural carbon sources in submerged basal salts media. A complete, fully coordinated ligninolytic system is likely not expressed by P. chrysosporium on ball-milled wood, because a potential route for regulatory feedback has been eliminated: the cellulose and hemicellulose in this substrate is readily accessible to enzymes, and thus ligninolysis is not essential for growth. An alternative approach is to compare levels of gene expression just before and after the onset of secondary metabolism and extracellular substrate oxidation by P. chrysosporium as it utilizes solid wood as its carbon source. If this can be done, and decay of the substrate is also confirmed, then the genes undergoing marked changes in expression during the metabolic transition can be identified with greater confidence. Although not all such genes are expected to have roles in biodegradation, this strategy may identify interesting candidates for future investigation. Here we report RNAseq-based transcriptomes to characterize changes in gene expression that occur during the transition to ligninolytic metabolism.
2015-09-16 | GSE69461 | GEO
Project description:We have studied the physiological response of the fungus Aspergillus niger when exposed to wheat straw as a model lignocellulosic substrate. Using RNA-sequencing we showed that, 24 hours after exposure to straw, gene expression of known plant cell wall degrading enzymes represents a huge investment for the cells (about 20 % of the total mRNA). Our results also uncovered new esterases and surface interacting proteins that might form part of the fungal degradative arsenal. We also show that antisense transcripts are abundant and that their expression can be regulated by conditions.
2012-08-27 | GSE33852 | GEO
Project description:We have studied the physiological response of the fungus Aspergillus niger when exposed to wheat straw as a model lignocellulosic substrate. Using RNA-sequencing we showed that, 24 hours after exposure to straw, gene expression of known plant cell wall degrading enzymes represents a huge investment for the cells (about 20 % of the total mRNA). Our results also uncovered new esterases and surface interacting proteins that might form part of the fungal degradative arsenal. We also show that antisense transcripts are abundant and that their expression can be regulated by conditions. Triplicate samples of A. niger N402 taken at each of three timepoints: After 48 h growth in minimal media with Glucose as sole carbon source, After transfer to Wheat Straw media for 24 h and 5 h after after the exogenous addition of glucose to the wheat starw media.
2012-08-27 | E-GEOD-33852 | biostudies-arrayexpress