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.
Project description:The ascomycete Trichoderma reesei is one of the most well studied cellulolytic fungi and widely used in the biotechnology industry, as in the production of second-generation bioethanol. Carbon catabolite repression (CCR) mechanism adopted by T. reesei is mediated by the transcription factor CRE1 and consists in the repression of genes related to the production of cellulase when a readily available carbon source is present in the medium. Using RNA sequencing this study aims to contribute to understanding of CCR during growth in cellulose and glucose, by comparing the mutant strain of T. reesei Δcre1 with its parental, QM9414.
Project description:Lactose (1,4-0-M-CM-^_-d-galactopyranosyl-d-glucose), a by-product from cheese manufacture or whey processing industries, is known to induce the formation of plant biomass hydrolyzing enzymes needed for the biorefinery industry in the fungus Trichoderma reesei, but the reason for this induction and the underlying mechanism are not fully understood. Here, we used systems analysis of the Trichoderma reesei transcriptome during utilization of lactose. We found that the respective CAZome encoded glycosyl hydrolases specifically tailored for the attack of monocotyledon xyloglucan. In addition, genes for a high number of putative transporters of the major facilitator superfamily were also induced. Systematic knock out of them identified a gene whose knock-out completely impaired lactose utilization and cellulase induction in Trichoderma reesei. These data shed new light on the mechanism by which Trichoderma reesei metabolizes lactose and illuminate the key role of M-CM-^_-D-galactosides in habitat specificity of this fungus. We used two biological replicas of Trichoderma reesei growing on lactose, glucose and glycerol
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. The strain QM9978 has a cellulase negative phenotype and therefore presents a valuable tool for understanding the mechanisms underlying cellulase regulation. A transcriptomic analyses of the cellulase negative strain QM9978 and the original strain QM6a have been performed to identify the genetic differences between QM6a and QM9978 leading to the cellulase-negative phenotype
Project description:We investigated the function of the SNX/H-type regulator of G-protein signaling (RGS) protein RGS4 and found alterations in enzyme regulation, stress response, siderophore production and metabolism of several carbon sources in light and darkness
Project description:The disruption of vacuolar protein sorting related genes vps13 and vps21 in filamentou fungi Trichoderma reesei resulted in a dramtic increase in cellulase transcription especially in the late Avicel induction phase, relieving the RESS (REpression under Secretion Stress) effect. Great interest arisen concered about the reason and underlying mechanism of vps13 and vps21 disruption for increased cellulase transcription. Thus, transcriptome analysis through RNA-Seq could give a deep insight of the potential pathways involved in enhanced cellulase transcription in late Avicel induction.
Project description:Filamentous fungus (anamorph: Trichoderma reesei; teleomorph: Hypocrea jecorina) important to industry for its cellulase production
Project description:MicroRNAs (miRNAs) are small non-coding RNAs capable of negatively regulating gene expression. Trichoderma reesei is an industrial filamentous fungus that can secrete abundant hydrolases for cellulosic biofuels. Recently, microRNA-like RNAs (milRNAs) were discovered in several filamentous fungi rather than T. reesei. The purpose of this study was to explore the presence of milRNA in T. reesei, to characterize the differential expression of T. reesei milRNA under cellulose induction, and to reveal the target genes of milRNA involved in cellulase production. Two small RNA libraries of cellulose induction (IN) or non-induction (CON) were generated and sequenced using Solexa sequencing technology. A total of 664,463 and 529,545 unique sequences, representing 1,271 and 1,021 unique small RNAs, were obtained from the IN and CON samples, respectively. Thirteen milRNAs were finally identified in T. reesei using the hairpin structure analysis. The milRNAs profiles obtained in deep sequencing were validated by RT-qPCR assay. The miRanda program predicts a number of potential targets for T. reesei milRNAs, including several hydrolases and carbon catabolite repressor Cre1.The presence and differential expression of T. reesei milRNAs, along with their predicted targets indicate that milRNAs might play a regulatory role in cellulase induction. This work lays foundation for further functional study of fungal milRNAs and their industrial application.
Project description:We have examined and compared the transcriptome of T. reesei growing on wheat straw and lactose as carbon sources under otherwise similar conditions. Gene expression on wheat straw exceeded that on lactose, and 1619 genes were found to be only induced on wheat straw but not on lactose. They comprised 30 % of the CAZome, but were also enriched in genes associated with phospholipid metabolism, DNA synthesis and repair and iron homeostatis. Two thirds of the CAZome was expressed both on wheat straw as well as on lactose, but 60 % of it at least >2-fold higher on the former. Major wheat straw specific genes comprised xylanases, chitinases and M-CM-^_-mannosidases. Interestingly, the latter two CAZyme families were significantly higher expressed in a strain in which xyr1 encoding the major regulator of cellulase and hemicellulase biosynthesis is non-functional, demonstrating that XYR1 is a repressor of these genes. We used two biological replicas of four T. reesei strains growing on glucose, lactose, and on wheat straw
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.