Project description:High-throughput sequencing reveals that tree species selected highly diverse fungal communities harboring different lignocellulolytic enzymes
Project description:Thermothelomyces thermophilus, formerly known as Myceliophthora thermophila, is used in industry to produce lignocellulolytic enzymes and heterologous proteins. However, the transcriptional network driving the expression of these proteins remains elusive. As a first step to systematically uncover this network, we investigated growth, protein secretion, and transcriptomic fingerprints of strains deficient in the cellulolytic transcriptional regulators Clr1, Clr2, and Clr4, respectively. The genes encoding Clr1, Clr2, and Clr4 were individually deleted using split marker or the CRISPR/Cas12a technology and the resulting strains as well as the parental strain were cultivated in bioreactors under chemostat conditions using glucose as carbon source. During steady state conditions, cellulose was added instead of glucose to study the genetic and cellular responses in all four strains to the shift in carbon source availability. Notably, the clr1 and clr2 deletion strains were unable to continue to grow on cellulose, demonstrating a key role of both regulators in cellulose catabolism. Their transcriptomic fingerprints uncovered not only a lack of cellulase gene expression but also reduced expression of genes predicted to encode hemicellulases, pectinases, and esterases. In contrast, the growth of the clr4 deletion strain was very similar compared to the parental strain. However, a much stronger expression of cellulases, hemicellulases, pectinases, and esterases was observed. The data gained in this study suggest that both transcriptional regulators Clr1 and Clr2 activate the expression of genes predicted to encode cellulases as well as hemicellulases, pectinases, and esterases. They further suggest that Clr1 controls the basal expression of cellulases and initiates the main lignocellulolytic response to cellulose via induction of clr2 expression. In contrast, Clr4 seems to act as a repressor of the lignocellulolytic response presumably via controlling clr2 expression. Comparative transcriptomics in all four strains revealed potentially new regulators in carbohydrate catabolism and lignocellulolytic enzyme expression that define a candidate gene list for future analyses.
Project description:Three-day metatranscriptome of surface gravel plain soils from the Central Namib Desert. Samples were collected at four times (6:00, 12:00, 18:00 and 24:00h) on each day (n=12). rRNA-depleted RNA was used to construct stranded libraries with the ScriptSeq v2 complete kit (Epicentre) adding unique barcodes in TruSeq adapters (ScriptSeq Index PCR primers, set 1, Epicentre). Libraries were single-end sequenced in a NextSeq 500 v2 sequencer, with read length of 75bp.
Project description:The filamentous fungus Penicillium oxalicum can secret various enzymes for efficient saccharification of plant biomass materials. Expression of the constitutively active forms of transcriptional activators ClrB, XlnR and AraR could trigger the production of different sets of lignocellulolytic enzymes. Here, the transcriptomes of the three engineered strains were compared with that of wild type in the medium without carbon source.
2020-12-05 | GSE162657 | GEO
Project description:Halophilic Communities as a Source for Novel Lignocellulolytic Enzymes
Project description:Digital gene expression profiling (DGE) was used to compare the responses of Penicillium decumbens strains to different carbon sources including glucose, cellulose and cellulose-wheat bran. In both wild-type strain 114-2 and cellulase hyperproducing mutant JU-A10-T, transcription of lignocellulolytic enzymes were significantly up-regulated in the presense of cellulose. Relative to 114-2, coordinated up-regulation of lignocellulolytic enzymes and down-regulation of amylases and proteases were observed in JU-A10-T, especially in the cellulose-wheat bran medium. The expression of the principal β-glucosidase BGLI gene was not elevated in JU-A10-T, like the cellulases and hemicellulases, suggesting a different regulatory mechanism for this enzyme. Functional analysis of genes up-regulated in JU-A10-T relative to 114-2 also showed enrichment of proteins involved in amino acid synthesis, protein synthesis, and post-translational modification, compatible with the higher level of production of secreted proteins in JU-A10-T.