Project description:White-rot basidiomycete fungi are potent degraders of plant biomass with the ability to mineralize all lignocellulose components. Recent comparative genomics studies showed that these fungi use a wide diversity of enzymes for wood degradation. In order to improve our understanding on the enzymatic mechanisms leading to lignocellulose breakdown, we analysed the early response of the white-rot fungus Pycnoporus coccineus CIRM-BRFM310 to various lignocellulosic substrates at two time points; Day 3 and Day 7.
Project description:White rot fungi are able to degrade woody lignin and other persistent organic compounds including artificial chemicals (e.g. chlorinated dioxin) in secondary metabolism. This ability has potential in a wide range of biotechnological applications including remediation of organopollutants and the industrial processing of paper and textiles. Ligninolytic fungi secondarily secrete extracellular oxidative enzymes thought to play an important role in these compounds decay. However, detail of metabolic pathway and initiation signals of the degradation system is unclear. To investigate genes directly and indirectly related to it, we constructed long serial analysis of gene expression (Long SAGE) library from the most studied white rot fungus, Phanerochaete chrysosporium. Keywords: transcriptome profiling
Project description:White-rot basidiomycete fungi are potent degraders of plant biomass with the ability to mineralize all lignocellulose components. Recent comparative genomics studies showed that these fungi use a wide diversity of enzymes for wood degradation. Deeper functional analyses are however necessary to understand the enzymatic mechanisms leading to lignocellulose breakdown. The Polyporale fungus Pycnoporus coccineus CIRM-BRFM310 grows well on both coniferous and deciduous wood. In the present study we analyzed the early response of the fungus to softwood (pine) and hardwood (aspen) feedstocks.
Project description:White rot fungi are able to degrade woody lignin and other persistent organic compounds including artificial chemicals (e.g. chlorinated dioxin) in secondary metabolism. This ability has potential in a wide range of biotechnological applications including remediation of organopollutants and the industrial processing of paper and textiles. Ligninolytic fungi secondarily secrete extracellular oxidative enzymes thought to play an important role in these compounds decay. However, detail of metabolic pathway and initiation signals of the degradation system is unclear. To investigate genes directly and indirectly related to it, we constructed long serial analysis of gene expression (Long SAGE) library from the most studied white rot fungus, Phanerochaete chrysosporium. Keywords: transcriptome profiling To analyze the transcriptome profile during the initiation of manganese peroxidase (MnP) and lignin peroxidase (LiP) production in Phanerochaete chrysosporium, we constructed the day 3 culture (just started the enzyme production) library and the day 2 culture (the activity of enzymes is not detected) library.
Project description:Unique ability of basidiomycete white rot fungi to degrade all components of plant cell walls makes them indispensable organisms in global carbon cycle. In this study, we analyzed proteomes of two closely related white rot fungi, Obba rivulosa and Gelatoporia subvermispora, while growing on solid spruce wood, and defined a core set of CAZymes that was shared between these species including the orthologous enzymes. Similar production pattern of these CAZymes indicate their key role in plant biomass degradation and need for their further biochemical characterization. The obtained results give an insight into specific enzymes and enzyme sets that are produced during the degradation of solid spruce wood. These findings expand the knowledge on enzyme production in nature-mimicking conditions and may contribute to exploitation of white rot fungi and their enzymes in biotechnological applications.
Project description:The ability to obtain carbon and energy is a major requirement to exist in any environment. For several ascomycete fungi (post-)genomic analyses have shown that species that occupy a large variety of habitats possess a diverse enzymatic machinery, while species with a specific habitat have a more focused enzyme repertoire that is well-adapted to the prevailing substrate. White-rot basidiomycete fungi also live in a specific habitat, as they are found exclusively in wood. In this study we evaluated how well the white-rot fungus Dichomitus squalens has adapted to degrade its natural wood substrate. The transcriptome and exoproteome of D. squalens were analysed after cultivation on two natural substrates, aspen and spruce wood, and two non-woody substrates, wheat bran and cotton seed hulls. D. squalens produced ligninolytic enzymes mainly at the early time point of the wood cultures, indicating the need to degrade lignin to get access to wood polysaccharides. Surprisingly, the response of the fungus to the non-woody polysaccharides was nearly as good match to the substrate composition as observed for the wood polysaccharides. This indicates that D. squalens has preserved its ability to efficiently degrade plant polysaccharides not present in its natural habitat.
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.