Effect of LAE1 gene deletion on gene expression in Trichoderma
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ABSTRACT:
ORGANISM(S): Trichoderma reesei
PROVIDER: GSE22687 | GEO | 2011/01/01
SECONDARY ACCESSION(S): PRJNA128327
REPOSITORIES: GEO
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Project description:The mitosporic fungus Trichoderma reesei is an industrial producer of enzymes for degradation of lignocellulosic polysaccharides to soluble monomers that can be fermented to biofuels. The genes encoding these enzymes in T. reesei have recently been shown to be clustered in the genome. Here we will show that the expression of these genes is epigenetically controlled at the heterochromatin level by the protein methyltransferase LAE1. Deletion of lae1 led to a loss of expression of the major cellulase and hemicellulase encoding genes, and resulted in an inability to grow on cellulose. The cellulase null phenotype was also seen with known soluble inducers of enzymes active on cellulose. In contrast, introduction of a second copy of lae1 or its enhanced expression under a strong constitutive promoter resulted in increased levels of cellulases. Thus, our data provides an experiment-based explanation for the advantage for clustering of cellulases in the genome of T. reesei, and imply that the heterochromatin structure is a major determinant of cellulase gene expression and hence an attractive target for strain improvement. We used two biological replicas of four T. reesei strains growing on lactose, the parent strain (QM9414), a delta-lae1, and two overexpressing strains (tef1:lae1 mutant 1 and mutant 2).
2011-01-01 | E-GEOD-22687 | biostudies-arrayexpress
Project description:Fungal degradation of lignocellulosic biomass requires various (hemi-)cellulases and plays key roles in biological carbon cycle. Although cellulases induction recently described in some saprobic filamentous fungi, regulation of cellulase transcription has not been studied thoroughly. Here, we identified and characterized the novel cellulase regulation factors clr-4 in Neurospora crassa and its ortholog Mtclr-4 in Myceliophthora thermophila. Deletion of clr-4 and Mtclr-4 displayed similarly defective phenotypes in cellulolytic enzymes production and activities. Transcriptomics analysis of Δclr-4/ΔMtclr-4 revealed down-regulation of not only encoding genes of (hemi-)cellulases and pivotal regulators (clr-1, clr-2 and xyr-1), but also the key genes of cAMP signaling pathway such as adenylate cyclase cr-1. Consistently, the significant decreased levels of intracellular cAMP were observed in Δclr-4/ΔMtclr-4 compared to wild-type during cellulose utilization. Electrophoretic mobility shift assays (EMSA) verified that CLR-4 could directly bind to the promoter regions of adenylyl cyclase (Nccr-1) and cellulose regulator clr-1, while MtCLR-4 bind to upstream regions of adenylyl cyclase Mtcr-1 and biomass deconstruction regulators Mtclr-2 and Mtxyr-1. Concluded, the novel cellulase expression regulators (CLR-4/MtCLR-4) findings here significantly enrich our understanding of the regulatory network of cellulose degradation and provide new targets for industrial fungi strain engineering for plant biomass deconstruction in biorefinery.
2021-03-18 | GSE111986 | GEO
Project description:Hypocrea jecorina (anamorph Trichoderma reesei) is one of the most well studied fungi used in biotechnology industry. This fungus is today a paradigm for the comercial scale production of different plant cell wall degrading enzymes, mainly cellulases and hemicellulases. The objective of this study was to analyze the transcriptional profiling of T. reesei grown in presence of cellulose, sophorose and glucose as the carbon source using RNA-seq approach.
2014-04-01 | GSE53629 | GEO
Project description:Hypocrea jecorina (anamorph Trichoderma reesei) is one of the most well studied fungi used in biotechnology industry. This fungus is today a paradigm for the comercial scale production of different plant cell wall degrading enzymes, mainly cellulases and hemicellulases. The objective of this study was to analyze the transcriptional profiling of T. reesei (Δxyr1) grown in presence of cellulose, sophorose and glucose as the carbon source using RNA-seq approach.
2017-02-09 | GSE66982 | GEO
Project description:The asexual spore or conidium plays a critical role in the life cycle of many filamentous fungi, being the primary means for dispersion in the environment. To investigate the transcriptional changes taking place during the sporulation phase in T. reesei, which culminates with the production of the conidiospores, microarray experiments were performed. Among the 1,994 distinct genes displaying >90 % confidence , a total of 900 were classified as differentially expressed, relative to time zero of sporulation, at at least one of the time points analyzed. The main functional categories (FunCat) overrepresented among upregulated genes were those involving solute transport, metabolism, transcriptional regulation, secondary metabolite synthesis, lipases, proteases and particularly cellulases and hemicellulases. Categories overrepresented among downregulated genes were especially those associated with ribosomal and mitochondrial functions. The upregulation of cellulase and hemicellulase genes was depending on the function of the positive transcriptional regulator XYR1, but the latter exerted no influence on sporulation itself. At least 20 % of the significantly regulated genes occured non-randomly distributed within the T. reesei genome suggesting an epigenetic component in the regulation of conidiation. The significant upregulation of cellulases and hemicellulases during conidiation, and thus cellulase and hemicelulase content in the spores of T. reesei lend to hypothesize that the ability to hydrolyse plant biomass is a major trait of this fungus to break dormancy and reinitiate vegetative growth after a period of facing unfavorable conditions One control and three sample points, checked by a marker enzyme for sporulation and by microscopy, were done in two biologicvao replicas
2011-12-08 | E-GEOD-27471 | biostudies-arrayexpress
Project description:The asexual spore or conidium plays a critical role in the life cycle of many filamentous fungi, being the primary means for dispersion in the environment. To investigate the transcriptional changes taking place during the sporulation phase in T. reesei, which culminates with the production of the conidiospores, microarray experiments were performed. Among the 1,994 distinct genes displaying >90 % confidence , a total of 900 were classified as differentially expressed, relative to time zero of sporulation, at at least one of the time points analyzed. The main functional categories (FunCat) overrepresented among upregulated genes were those involving solute transport, metabolism, transcriptional regulation, secondary metabolite synthesis, lipases, proteases and particularly cellulases and hemicellulases. Categories overrepresented among downregulated genes were especially those associated with ribosomal and mitochondrial functions. The upregulation of cellulase and hemicellulase genes was depending on the function of the positive transcriptional regulator XYR1, but the latter exerted no influence on sporulation itself. At least 20 % of the significantly regulated genes occured non-randomly distributed within the T. reesei genome suggesting an epigenetic component in the regulation of conidiation. The significant upregulation of cellulases and hemicellulases during conidiation, and thus cellulase and hemicelulase content in the spores of T. reesei lend to hypothesize that the ability to hydrolyse plant biomass is a major trait of this fungus to break dormancy and reinitiate vegetative growth after a period of facing unfavorable conditions
2011-12-08 | GSE27471 | GEO
Project description:The ascomycete Trichoderma reesei is an industrial producer of cellulolytic and hemicellulolytic enzymes and also serves as a model for investigations on these enzymes and their genes. Most of them are obligatorily dependent on the Zn(II)Cys(VI) transcriptional activator XYR1. XYR1 is constitutively expressed at a low basal, but induced in the presence of cellulase- and hemicellulose inducers, and transported into the nucleus. The factors mediating its import and export across the nuclear pore complexes (karyopherins) are therefore expected to play a key role in its function. We identified 14 karyopherins in T. reesei, of which 8 were predicted to be involved nuclear protein import. Their systematic knock-out and testing for cellulase formation identified KAP8 (an orthologue of A. nidulans KapI, and Saccharomyces cerevisiae Kap121/Pse1p) to be essential for cellulase gene expression, and for the appearance of GFP-XYR1 in the nucleus. Transcriptomic analysis of Δkap8 and a retransformant under cellulase-inducing conditions revealed the downregulation of 64 Cazymes in the Δkap8 strain under inducing conditions, including all cellulases and hemicellulases known to be under XYR1 control, and of 12 transcription factors of which 2 were known to be associated with cellulase regulation (ACE3, CLR2). Together, these new observations underscore the role of nuclear transport of XYR1 in the regulation of cellulase and hemicellulose gene expression in T. reesei, and identify KAP8 as the major karyopherin involved in this process. Two strains were used: T. reesei ku70 (pyr4-), in which the kap8 (=kapI/Pse1/Kap121) reading frame has been replaced by the T. reesei pyr4 gene; and a kap8-retransformant of the same strain and two time points for each strain T0h and T3h. All samples are in tricplicate.
2015-03-03 | E-GEOD-59600 | biostudies-arrayexpress
Project description:The mechanism of carbon catabolite repression (CCR) mediated by CRE1 in Trichoderma reesei emerged as a way to adapt to the environment in which the fungus is found. In situations where there is the presence of readily available carbon sources such as glucose, the fungus activates this mechanism and inhibits the production of cellulolytic complex enzymes to avoid unnecessary energy expenditure. CCR has been well described for the growth of T. reesei in cellulose and glucose, however, little is known about this process when the carbon source available to the fungus is sophorose, one of the most potent inducer of cellulase production. Thus, we performed high-throughput RNA sequencing using the Illumina/HiSeq-2000 to contribute to the understanding of CCR during cellulase formation in the presence of sophorose, by comparing the mutant Δcre1 with its parental strain, QM9414. Of the 9129 genes present in the genome of T. reesei, 184 were up- and 344 down-regulated in the mutant strain Δcre1 compared to QM9414. Genes belonging to CAZy, transcription factors and transporters are among the gene classes that were repressed by CRE1 in the presence of sophorose, most of which was regulated by CRE1 in an indirect way. Overall, there was a similarity in the profile of repressed genes when compared with another inducing carbon source, cellulose. These results contribute to a better understanding of CRE1-meadiated CCR in T. reesei when glucose comes from a potent inducer as sophorose, which can be very useful in improving the production of cellulases by the biotechnology sector.
2017-02-11 | GSE66915 | GEO
Project description:Hemicellulose, the second most abundant plant biomass fraction after cellulose, is widely viewed as a potential feedstock for the production of liquid fuels and other value-added materials. Degradation of hemicellulose by filamentous fungi requires production of many different enzymes, which are induced by biopolymers or its derivatives and regulated mainly at the transcriptional level through transcription factors (TFs). Neurospora crassa has been shown to express and secrete plant cell wall associated enzymes. To better understand genes specifically associated with degradation of hemicellulose, we identified 353 genes by transcriptome analysis of N. crassa wild type strain grown on beechwood xylan. Exposure to xylan induces 9 of the 19 predicted hemicellulase genes. The xylanolytic phenotype of strains with deletions in genes identified from the secretome and transcriptome analysis of wild type showed that none were essential for growth on beechwood xylan. The transcription factor XlnR/Xyr1 in Aspergillus and Trichoderma species is considered to be the major transcriptional regulator of genes encoding both cellulases and hemicellulases. We identified a xlnR/xyr1 homolog in N. crassa, NCU06971, termed xlr-1 (xylanase regulator 1). Deletion of xlr-1 in N. crassa abolishes the growth on xylan and xylose, but growth on cellulose was indistinguishable from wild type. To determine regulatory mechanisms associated with hemicellulose degradation, we explored the transcriptional regulon of XLR-1 under xylose and xylanolytic versus cellulolytic conditions. XLR-1 regulated only some predicted hemicellulase genes in N. crassa and was required for a full induction of several cellulase genes. Hemicellulase gene expression was induced by a combination of release from carbon catabolite repression (CCR) and induction. However, in N. crassa, xlr-1 is subject to non-CRE-1 mediated CCR. This systematic analysis provides the similarities and differences of hemicellulose degradation and regulation mechanisms used by N. crassa in comparison to other filamentous fungi. Four-condition experiments (minimal medium, xylan medium,xylose and Avicel medium) of mutant strain(xlr-1) compared to wild type strain; Cy3 and Cy5 dye swap
2012-03-26 | E-GEOD-34098 | biostudies-arrayexpress
Project description:Hemicellulose, the second most abundant plant biomass fraction after cellulose, is widely viewed as a potential feedstock for the production of liquid fuels and other value-added materials. Degradation of hemicellulose by filamentous fungi requires production of many different enzymes, which are induced by biopolymers or its derivatives and regulated mainly at the transcriptional level through transcription factors (TFs). Neurospora crassa has been shown to express and secrete plant cell wall associated enzymes. To better understand genes specifically associated with degradation of hemicellulose, we identified 353 genes by transcriptome analysis of N. crassa wild type strain grown on beechwood xylan. Exposure to xylan induces 9 of the 19 predicted hemicellulase genes. The xylanolytic phenotype of strains with deletions in genes identified from the secretome and transcriptome analysis of wild type showed that none were essential for growth on beechwood xylan. The transcription factor XlnR/Xyr1 in Aspergillus and Trichoderma species is considered to be the major transcriptional regulator of genes encoding both cellulases and hemicellulases. We identified a xlnR/xyr1 homolog in N. crassa, NCU06971, termed xlr-1 (xylanase regulator 1). Deletion of xlr-1 in N. crassa abolishes the growth on xylan and xylose, but growth on cellulose was indistinguishable from wild type. To determine regulatory mechanisms associated with hemicellulose degradation, we explored the transcriptional regulon of XLR-1 under xylose and xylanolytic versus cellulolytic conditions. XLR-1 regulated only some predicted hemicellulase genes in N. crassa and was required for a full induction of several cellulase genes. Hemicellulase gene expression was induced by a combination of release from carbon catabolite repression (CCR) and induction. However, in N. crassa, xlr-1 is subject to non-CRE-1 mediated CCR. This systematic analysis provides the similarities and differences of hemicellulose degradation and regulation mechanisms used by N. crassa in comparison to other filamentous fungi.
2012-03-26 | GSE34098 | GEO