Transcriptomic evidence that lignolytic fungi deconstruct fungal necromass and plant litter via similar pathways
Ontology highlight
ABSTRACT:
ORGANISM(S): Gloeophyllum trabeum Trametes versicolor
PROVIDER: GSE326267 | GEO | 2026/06/02
REPOSITORIES: GEO
Similar Datasets
Project description:Fungal necromass in soil represents the stable carbon pools. While fungi are known to decompose fungal necromass, how fungi decomopose melanin, remains poorly understood. Recently, Trichoderma species was found to be one of the most commonly associated fungi in soil, we have used a relevant fungal species, Trichoderma reesei, to characterized Genes involved in the decomposition of melanized and non-melanized necromass from Hyaloscypha bicolor.
2024-05-01 | GSE263516 | GEO
Project description:Decomposition of soil organic matter in forest soils is thought to be controlled by the activity of saprotrophic fungi, while biotrophic fungi including ectomycorrhizal fungi act as vectors for input of plant carbon. The limited decomposing ability of ectomycorrhizal fungi is supported by recent findings showing that they have lost many of the genes that encode hydrolytic plant cell-wall degrading enzymes in their saprophytic ancestors. Nevertheless, here we demonstrate that ectomycorrhizal fungi representing at least four origins of symbiosis have retained significant capacity to degrade humus-rich litter amended with glucose. Spectroscopy showed that this decomposition involves an oxidative mechanism and that the extent of oxidation varies with the phylogeny and ecology of the species. RNA-Seq analyses revealed that the genome-wide set of expressed transcripts during litter decomposition has diverged over evolutionary time. Each species expressed a unique set of enzymes that are involved in oxidative lignocellulose degradation by saprotrophic fungi. A comparison of closely related species within the Boletales showed that ectomycorrhizal fungi oxidized litter material as efficiently as brown-rot saprotrophs. The ectomycorrhizal species within this clade exhibited more similar decomposing mechanisms than expected from the species phylogeny in concordance with adaptive evolution occurring as a result of similar selection pressures. Our data shows that ectomycorrhizal fungi are potential organic matter decomposers, yet not saprotrophs. We suggest that the primary function of this decomposing activity is to mobilize nutrients embedded in organic matter complexes and that the activity is driven by host carbon supply. Comparative transcriptomics of ectomycorrhizal (ECM) versus brown-rot (BR) fungi while degrading soil-organic matter
2015-09-24 | E-GEOD-64897 | biostudies-arrayexpress
Project description:Decomposition of soil organic matter in forest soils is thought to be controlled by the activity of saprotrophic fungi, while biotrophic fungi including ectomycorrhizal fungi act as vectors for input of plant carbon. The limited decomposing ability of ectomycorrhizal fungi is supported by recent findings showing that they have lost many of the genes that encode hydrolytic plant cell-wall degrading enzymes in their saprophytic ancestors. Nevertheless, here we demonstrate that ectomycorrhizal fungi representing at least four origins of symbiosis have retained significant capacity to degrade humus-rich litter amended with glucose. Spectroscopy showed that this decomposition involves an oxidative mechanism and that the extent of oxidation varies with the phylogeny and ecology of the species. RNA-Seq analyses revealed that the genome-wide set of expressed transcripts during litter decomposition has diverged over evolutionary time. Each species expressed a unique set of enzymes that are involved in oxidative lignocellulose degradation by saprotrophic fungi. A comparison of closely related species within the Boletales showed that ectomycorrhizal fungi oxidized litter material as efficiently as brown-rot saprotrophs. The ectomycorrhizal species within this clade exhibited more similar decomposing mechanisms than expected from the species phylogeny in concordance with adaptive evolution occurring as a result of similar selection pressures. Our data shows that ectomycorrhizal fungi are potential organic matter decomposers, yet not saprotrophs. We suggest that the primary function of this decomposing activity is to mobilize nutrients embedded in organic matter complexes and that the activity is driven by host carbon supply.
2015-09-24 | GSE64897 | GEO
Project description:Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.
2018-11-30 | GSE110485 | GEO
Project description:Abstract: A large part of the nitrogen in forest soils is found in recalcitrant organic matter-protein complexes. Ectomycorrhizal fungi are thought to have a key role in the decomposition and mobilization of nitrogen from such complexes. The knowledge on the functional mechanisms of these processes, and how they are regulated by carbon from the host plant and the availability of more easily available forms of nitrogen sources are limited. We used spectroscopic analyses and transcriptome profiling to examine how the presence/absence of glucose and ammonium regulates the decomposition and mobilization of nitrogen from litter material by the ectomycorrhizal fungus Paxillus involutus. Amendments of glucose triggered the assimilation of nitrogen and the decomposition of the litter material. Concomitantly, the expression of genes encoding enzymes involved in oxidative (i.e. Fenton chemistry) degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism were upregulated in concert. Addition of ammonium had minute effects on both the expression of transcripts and decomposition of litter material, and only when glucose was present. Based on the spectroscopic analyses, three major types of chemical modifications of the litter material were observed. Each of them was correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggests that the expression of the decomposition and nitrogen assimilation machinery of ectomycorrhizal fungi can be firmly regulated by the host carbon supply, i.e. priming, and that the availability of inorganic nitrogen as such has limited effects on the saprotrophic activities. Rineau F, Shah F., Smits M.M., Persson P., Johansson T., Carleer R., Troein C., Tunlid A. (2013) Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus (submitted) A one-chip study (data from 12 subarrays collected from a 12-plex Nimblegen microarray (ID 467991) using total RNA recovered from three separate glass-bead cultures of Paxillus involutus (ATCC200175) after amendments of various soil-derived substrates. Transcriptome profiling to examine how the presence/absence of glucose and ammonium regulates the decomposition and mobilization of nitrogen from litter material by the ectomycorrhizal fungus Paxillus involutus.
2013-04-30 | E-GEOD-45303 | biostudies-arrayexpress
Project description:Abstract: A large part of the nitrogen in forest soils is found in recalcitrant organic matter-protein complexes. Ectomycorrhizal fungi are thought to have a key role in the decomposition and mobilization of nitrogen from such complexes. The knowledge on the functional mechanisms of these processes, and how they are regulated by carbon from the host plant and the availability of more easily available forms of nitrogen sources are limited. We used spectroscopic analyses and transcriptome profiling to examine how the presence/absence of glucose and ammonium regulates the decomposition and mobilization of nitrogen from litter material by the ectomycorrhizal fungus Paxillus involutus. Amendments of glucose triggered the assimilation of nitrogen and the decomposition of the litter material. Concomitantly, the expression of genes encoding enzymes involved in oxidative (i.e. Fenton chemistry) degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism were upregulated in concert. Addition of ammonium had minute effects on both the expression of transcripts and decomposition of litter material, and only when glucose was present. Based on the spectroscopic analyses, three major types of chemical modifications of the litter material were observed. Each of them was correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggests that the expression of the decomposition and nitrogen assimilation machinery of ectomycorrhizal fungi can be firmly regulated by the host carbon supply, i.e. priming, and that the availability of inorganic nitrogen as such has limited effects on the saprotrophic activities. Rineau F, Shah F., Smits M.M., Persson P., Johansson T., Carleer R., Troein C., Tunlid A. (2013) Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus (submitted)
2013-04-30 | GSE45303 | GEO
Project description:Deadwood plays a crucial role in forest ecosystems, but we have limited information about the specific fungal taxa and extracellular lignocellulolytic enzymes that are actively involved in the decomposition process in situ. To investigate this, we studied the fungal metaproteome of twelve deadwood tree species in a replicated, eight-year experiment. Key fungi observed included genera of white-rot fungi (Basidiomycota, e.g. Armillaria, Hypholoma, Mycena, Ischnoderma, Resinicium), brown-rot fungi (Basidiomycota, e.g. Fomitopsis, Antrodia), diverse Ascomycota including xylariacous soft-rot fungi (e.g. Xylaria, Annulohypoxylon, Nemania) and various wood-associated endophytes and saprotrophs (Ascocoryne, Trichoderma, Talaromyces). These fungi used a whole range of extracellular lignocellulolytic enzymes, such as peroxidases, peroxide-producing enzymes, laccases, cellulases, glucosidases, hemicellulases (xylanases) and lytic polysaccharide monooxygenases (LPMOs). Both the fungi and enzymes were tree-specific, with specialists and generalists being distinguished by network analysis. The extracellular enzymatic system was highly redundant, with many enzyme classes of different origins present simultaneously in all decaying logs. Strong correlations were found between peroxide-producing enzymes (oxidases) and peroxidases as well as LPMOs, and between ligninolytic, cellulolytic and hemicellulolytic enzymes. The overall protein abundance of lignocellulolytic enzymes was reduced by up to -30% in gymnosperm logs compared to angiosperm logs, and gymnosperms lacked ascomycetous enzymes, which may have contributed to the lower decomposition of gymnosperm wood. In summary, we have obtained a comprehensive and detailed insight into the enzymatic machinery of wood-inhabiting fungi in several temperate forest tree species, which can help to improve our understanding of the complex ecological processes in forest ecosystems.
2024-04-22 | PXD041962 | Pride
Project description:Wood-degrading fungi play a critical role in global carbon cycling, and their varied mechanisms for deconstruction offer pathways for industrial bioconversion. In this study, we used comparative genomics to isolate upregulation patterns among fungi with brown rot (carbohydrate-selective) or white rot (lignin-degrading) nutritional modes. Specifically, we used whole-transcriptome profiling to compare early, middle, and late decay stages on wood wafers, matching differentially-expressed gene (DEG) patterns with fungal growth and enzyme activities. This approach highlighted 34 genes uniquely upregulated in early brown rot stages, with notable candidates involved in generating reactive oxygen species (ROS) as a pretreatment mechanism during brown rot. This approach further isolated 18 genes in late brown rot stages that may be adapted to handle oxidatively-reacted lignocellulose components. By summing gene expression levels in functional classes, we also identified a broad and reliable distinction in glycoside hydrolase (GH) versus lignocellulose oxidative (LOX) transcript counts that may reflect the energy investment burden of lignin-degrading machinery among white rot fungi.
2018-01-05 | GSE108189 | GEO
Project description:Brown rot fungi evolved the unique strategy to efficiently decay wood structures and selectively extract carbohydrates, and this involved the sophistical regulation of functional genes (Zhang et al., PNAS, 2016, 113: 10968-). However, the regulatory mechanisms of brown rot genes were not well known, impeding the implication and application of brown rot machinery in biomass conversions. In this work, we systematically studied the roles of environmental carbon signals (e.g., aspen, cellobiose, glucose and no-carbon) in regulating gene expression in model brown rot fungus Postia placenta by RNA-seq. We found the complex substrate aspen (Populus sp.), but not the commonly recognized disaccharide cellobiose, was the universal inducer for Carbohydrate Active Enzymes (CAZYs) expression. Even though, cellobiose clearly induced the expression of cellulase (GH5 and GH12, endoglucanase) and xylanase (GH10, endoxylanase) (cellobiose vs. no-carbon, fold change > 4), as we reported previously (Zhang and Schilling, FGB, 2017, 106: 1-). When response to easy to use carbons, P. placenta lost the CCR effect on the main-chain cleaving CAZYs expression, but kept this repressing effect on side-chain cleaving CAZYs and AAs, which indicated a clear adaption relative to that in saprotrophic ascomycete ancestors. This “loss of CCR effect” was independent of the glucose concentrations. To explore the distinctive brown rot regulatory machinery, the gene modules subjected to inducing or CCR effects were then used to predict the regulatory motifs and transcriptional factors to build the regulatory network in P. placenta. Together, these findings will facilitate us to understand the adaptions of regulatory elements in brown rot fungi, as well as the efficient brown rot strategy.
2018-09-11 | GSE119714 | GEO
Project description:The decomposition of large woody material is an important process in forest carbon cycling and nutrient release. Cord-forming saprotrophic basidiomycete fungi create non-resource limited mycelial networks between decomposing branches, logs and tree stumps on the forest floor where colonisation of new resource is often associated with the replacement of incumbent decay communities. Cord-forming species often dominate competition hierarchies in controlled paired antagonism experiments and have been shown to translocate resource to support colonisation and produce inhibitory metabolites. To date, antagonism experiments have mostly placed competing fungi in direct contact, while in nature cord-forming saprobes encounter colonised wood as mycelia in a network. Here we used soil-based microcosms that allowed foraging cord-forming Hypholoma fasciculare to encounter a wood block colonised by Trametes versicolor and conducted transcriptomic and proteomic analysis of the interaction. Cellular processes and metabolic responses to the competitive interaction were identified, where protein turnover featured strongly for both species. H. fasciculare demonstrated an exploitative profile with increased transcription of enzymes that targeted carbohydrate polymers of the substrate and in RNA and ribosome processing. T. versicolor showed a shift in signalling, energy generation and amino acid metabolism. Putative genes involved in secondary metabolite production were identified in both species. This study highlights the importance of ecologically-relevant experimental design when considering complex processes such as community development during wood decomposition
2024-09-20 | GSE245088 | GEO