Genome-wide Transcriptional Responses of the Filamentous Fungus Aspergillus niger to Lignocellulose (Wheat straw) using RNA-sequencing
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ABSTRACT:
ORGANISM(S): Aspergillus niger
PROVIDER: GSE33852 | GEO | 2012/08/27
SECONDARY ACCESSION(S): PRJNA148183
REPOSITORIES: GEO
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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
Project description:The induction of genes in response to exposure of T. reesei to wheat straw was explored using genome-wide RNA-seq and compared to published RNA-seq data and model of how A. niger senses and responds to the lignocellulose. After 24 h of exposure to straw, transcript levels of known and predicted lignocellulose-degrading enzymes increased to around 8% of total cellular mRNA in T. reesei, which was much less when compared to A. niger. The bulk of enzymes used to deconstruct wheat straw is similar in both fungi. Other, non-plant cell wall-degrading enzymes which may aid in lignocellulose degradation were also uncovered in T. reesei and similar to those described in A. niger. Antisense transcripts were also shown to be present in T. reesei and their expession can be regulated by the respective growth condition.
2013-04-01 | GSE44648 | GEO
Project description:The induction of genes in response to exposure of T. reesei to wheat straw was explored using genome-wide RNA-seq and compared to published RNA-seq data and model of how A. niger senses and responds to the lignocellulose. After 24 h of exposure to straw, transcript levels of known and predicted lignocellulose-degrading enzymes increased to around 8% of total cellular mRNA in T. reesei, which was much less when compared to A. niger. The bulk of enzymes used to deconstruct wheat straw is similar in both fungi. Other, non-plant cell wall-degrading enzymes which may aid in lignocellulose degradation were also uncovered in T. reesei and similar to those described in A. niger. Antisense transcripts were also shown to be present in T. reesei and their expession can be regulated by the respective growth condition. Triplicate samples of T. reesei cultivated in each of the three following conditions were taken: 1) After 48 h growth in glucose-based minimal media; 2) After transfer of mycelia from glucose-based media into media containing wheat straw as a sole carbon source and 3) 5 h after addition of glucose to straw cultures.
2013-04-01 | E-GEOD-44648 | biostudies-arrayexpress
Project description:Background: Saprobic fungi are the predominant industrial sources of Carbohydrate Active enZymes (CAZymes) used for the saccharification of lignocellulose during the production of second generation biofuels. The production of more effective enzyme cocktails is a key objective for efficient biofuel production. To achieve this objective, it is crucial to understand the response of fungi to lignocellulose substrates. Our previous study used RNA-seq to identify the genes induced in Aspergillus niger in response to wheat straw, a biofuel feedstock, and showed that the range of genes induced was greater than previously seen with simple inducers [GSE33852]. Results: In this work we used RNA-seq to identify the genes induced in A. niger in response to short rotation coppice willow and compared this with the response to wheat straw from our previous study, at the same time-point. The response to willow showed a large increase in expression of genes encoding CAZymes. Genes encoding the major activities required to saccharify lignocellulose were induced on willow such as endoglucanases, cellobiohydrolases and xylanases. The transcriptome response to willow had many similarities with the response to straw with some significant differences in the expression levels of individual genes which are discussed in relation to differences in substrate composition or other factors. Differences in transcript levels include higher levels on wheat straw from genes encoding enzymes classified as members of GH62 (an arabinofuranosidase) and CE1 (a feruloyl esterase) CAZy families whereas two genes encoding endoglucanases classified as members of the GH5 family had higher transcript levels when exposed to willow. There were changes in the cocktail of enzymes secreted by A. niger when cultured with willow or straw. Assays for particular enzymes as well as saccharification assays were used to compare the enzyme activities of the cocktails. Wheat straw induced an enzyme cocktail that saccharified wheat straw to a greater extent than willow. Genes not encoding CAZymes were also induced on willow such as hydrophobins as well as genes of unknown function. Several genes were identified as promising targets for future study. Conclusions: By comparing this first study of the global transcriptional response of a fungus to willow with the response to straw, we have shown that the inducing lignocellulosic substrate has a marked effect upon the range of transcripts and enzymes expressed by A. niger. The use by industry of complex substrates such as wheat straw or willow could benefit efficient biofuel production. Six samples in total consisting of duplicate shake flask Aspergillus niger cultures from three conditions: glucose 48 h, willow 24 h, willow 24 h + glucose 5 h
2015-04-13 | E-GEOD-62284 | biostudies-arrayexpress
Project description:Background: Saprobic fungi are the predominant industrial sources of Carbohydrate Active enZymes (CAZymes) used for the saccharification of lignocellulose during the production of second generation biofuels. The production of more effective enzyme cocktails is a key objective for efficient biofuel production. To achieve this objective, it is crucial to understand the response of fungi to lignocellulose substrates. Our previous study used RNA-seq to identify the genes induced in Aspergillus niger in response to wheat straw, a biofuel feedstock, and showed that the range of genes induced was greater than previously seen with simple inducers [GSE33852]. Results: In this work we used RNA-seq to identify the genes induced in A. niger in response to short rotation coppice willow and compared this with the response to wheat straw from our previous study, at the same time-point. The response to willow showed a large increase in expression of genes encoding CAZymes. Genes encoding the major activities required to saccharify lignocellulose were induced on willow such as endoglucanases, cellobiohydrolases and xylanases. The transcriptome response to willow had many similarities with the response to straw with some significant differences in the expression levels of individual genes which are discussed in relation to differences in substrate composition or other factors. Differences in transcript levels include higher levels on wheat straw from genes encoding enzymes classified as members of GH62 (an arabinofuranosidase) and CE1 (a feruloyl esterase) CAZy families whereas two genes encoding endoglucanases classified as members of the GH5 family had higher transcript levels when exposed to willow. There were changes in the cocktail of enzymes secreted by A. niger when cultured with willow or straw. Assays for particular enzymes as well as saccharification assays were used to compare the enzyme activities of the cocktails. Wheat straw induced an enzyme cocktail that saccharified wheat straw to a greater extent than willow. Genes not encoding CAZymes were also induced on willow such as hydrophobins as well as genes of unknown function. Several genes were identified as promising targets for future study. Conclusions: By comparing this first study of the global transcriptional response of a fungus to willow with the response to straw, we have shown that the inducing lignocellulosic substrate has a marked effect upon the range of transcripts and enzymes expressed by A. niger. The use by industry of complex substrates such as wheat straw or willow could benefit efficient biofuel production.
2015-04-13 | GSE62284 | 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. 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:Renewables-based biotechnology depends on enzymes to degrade plant lignocellulose to simple sugars that are converted to fuels or high-value products. Identification and characterization of such lignocellulose degradative enzymes could be fast-tracked by availability of an enzyme activity measurement method that is fast, label-free, uses minimal resources and allows direct identification of generated products. We developed such a method by applying carbohydrate arrays coupled with MALDI-ToF mass spectrometry to identify reaction products of carbohydrate active enzymes (CAZymes) of the filamentous fungus Aspergillus niger. We describe the production and characterization of plant polysaccharide-derived oligosaccharides and their attachment to hydrophobic self-assembling monolayers on a gold target. We verify effectiveness of this array for detecting exo- and endo-acting glycoside hydrolase activity using commercial enzymes, and demonstrate how this platform is suitable for detection of enzyme activity in relevant biological samples, the culture filtrate of A. niger grown on wheat straw. In conclusion, this versatile method is broadly applicable in screening and characterisation of activity of CAZymes, such as fungal enzymes for plant lignocellulose degradation with relevance to biotechnological applications as biofuel production, the food and animal feed industry.
2018-10-26 | PXD005699 | Pride
Project description:Guar gum consists mainly of galactomannan, and constitutes the endosperm of guar seeds that acts as a reserve polysaccharide for germination. Due to its molecular structure and physical properties, this biopolymer has been considered as one of the most important and widely used gums in industry. However, for many of these applications this (hemi-)cellulosic structure needs to be modified or (partially) depolymerized in order to customize and improve its physicochemical properties. In this study, transcriptome was employed to decipher the complete enzymatic arsenal for guar gum depolymerization by Aspergillus niger.
2020-08-11 | GSE119310 | 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 aim of this study was to find candidate genes in A. niger involved in the vanillic acid metabolic pathway.
2021-08-11 | GSE154865 | GEO