Transcriptional profiling of biomass degradation-related genes during Trichoderma reesei growth on different carbon sources

2014 ◽  
Vol 173 ◽  
pp. 59-64 ◽  
Author(s):  
Xiuzhen Chen ◽  
Yingfeng Luo ◽  
Hongtao Yu ◽  
Yuhui Sun ◽  
Hong Wu ◽  
...  
mSystems ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Amanda Cristina Campos Antonieto ◽  
Karoline Maria Vieira Nogueira ◽  
Renato Graciano de Paula ◽  
Luísa Czamanski Nora ◽  
Murilo Henrique Anzolini Cassiano ◽  
...  

ABSTRACT Filamentous fungi are remarkable producers of enzymes dedicated to the degradation of sugar polymers found in the plant cell wall. Here, we integrated transcriptomic data to identify novel transcription factors (TFs) related to the control of gene expression of lignocellulosic hydrolases in Trichoderma reesei and Aspergillus nidulans. Using various sets of differentially expressed genes, we identified some putative cis-regulatory elements that were related to known binding sites for Saccharomyces cerevisiae TFs. Comparative genomics allowed the identification of six transcriptional factors in filamentous fungi that have corresponding S. cerevisiae homologs. Additionally, a knockout strain of T. reesei lacking one of these TFs (S. cerevisiae AZF1 homolog) displayed strong reductions in the levels of expression of several cellulase-encoding genes in response to both Avicel and sugarcane bagasse, revealing a new player in the complex regulatory network operating in filamentous fungi during plant biomass degradation. Finally, RNA sequencing (RNA-seq) analysis showed the scope of the AZF1 homologue in regulating a number of processes in T. reesei, and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) provided evidence for the direct interaction of this TF in the promoter regions of cel7a, cel45a, and swo. Therefore, we identified here a novel TF which plays a positive effect in the expression of cellulase-encoding genes in T. reesei. IMPORTANCE In this work, we used a systems biology approach to map new regulatory interactions in Trichoderma reesei controlling the expression of genes encoding cellulase and hemicellulase. By integrating transcriptomics related to complex biomass degradation, we were able to identify a novel transcriptional regulator which is able to activate the expression of these genes in response to two different cellulose sources. In vivo experimental validation confirmed the role of this new regulator in several other processes related to carbon source utilization and nutrient transport. Therefore, this work revealed novel forms of regulatory interaction in this model system for plant biomass deconstruction and also represented a new approach that could be easy applied to other organisms.


mSphere ◽  
2017 ◽  
Vol 2 (3) ◽  
Author(s):  
Eva Stappler ◽  
Christoph Dattenböck ◽  
Doris Tisch ◽  
Monika Schmoll

ABSTRACT In fungi, most metabolic processes are subject to regulation by light. For Trichoderma reesei, light-dependent regulation of cellulase gene expression is specifically shown. Therefore, we intended to unravel the relationship between regulation of enzymes by the carbon source and regulation of enzymes by light. Our two-dimensional analysis included inducing and repressing carbon sources which we used to compare light-specific regulation to dark-specific regulation and to rule out effects specific for a single carbon source. We found close connections with respect to gene regulation as well as significant differences in dealing with carbon in the environment in light and darkness. Moreover, our analyses showed an intricate regulation mechanism for substrate degradation potentially involving surface sensing and provide a basis for knowledge-based screening for strain improvement. In fungi, most metabolic processes are subject to regulation by light. Trichoderma reesei is adapted to degradation of plant cell walls and regulates production of the required enzymes in a manner dependent on the nutrient source and the light status. Here we investigated the interrelated relevance of two regulation levels of the transcriptome of T. reesei: light regulation and carbon source-dependent control. We show that the carbon source (cellulose, lactose, sophorose, glucose, or glycerol) is the major source of variation, with light having a modulating effect on transcript regulation. A total of 907 genes were regulated under cellulase-inducing conditions in light, and 947 genes were regulated in darkness, with 530 genes overlapping (1,324 in total). Only 218 of the 1,324 induction-specific genes were independent of light and not regulated by the BLR1, BLR2, and ENV1 photoreceptors. Analysis of the genomic distribution of genes regulated by light upon growth on cellulose revealed considerable overlap of light-regulated clusters with induction-specific clusters and carbohydrate-active enzyme (CAZyme) clusters. Further, we found evidence for the operation of a sensing mechanism for solid cellulosic substrates, with regulation of genes such as swo1, cip1, and cip2 or of genes encoding hydrophobins which is related to the cyclic AMP (cAMP)-dependent regulatory output of ENV1. We identified class XIII G-protein-coupled receptors (GPCRs) CSG1 and CSG2 in T. reesei as putative cellulose/glucose-sensing GPCRs. Our data indicate that the cellulase regulation pathway is bipartite, comprising a section corresponding to transcriptional regulation and one corresponding to posttranscriptional regulation, with the two connected by the function of CSG1. IMPORTANCE In fungi, most metabolic processes are subject to regulation by light. For Trichoderma reesei, light-dependent regulation of cellulase gene expression is specifically shown. Therefore, we intended to unravel the relationship between regulation of enzymes by the carbon source and regulation of enzymes by light. Our two-dimensional analysis included inducing and repressing carbon sources which we used to compare light-specific regulation to dark-specific regulation and to rule out effects specific for a single carbon source. We found close connections with respect to gene regulation as well as significant differences in dealing with carbon in the environment in light and darkness. Moreover, our analyses showed an intricate regulation mechanism for substrate degradation potentially involving surface sensing and provide a basis for knowledge-based screening for strain improvement.


2007 ◽  
Vol 137-140 (1-12) ◽  
pp. 195-204 ◽  
Author(s):  
Zsuzsa Benkő ◽  
Eszter Drahos ◽  
Zsolt Szengyel ◽  
Terhi Puranen ◽  
Jari Vehmaanperä ◽  
...  

2003 ◽  
Vol 69 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Nina Aro ◽  
Marja Ilmén ◽  
Anu Saloheimo ◽  
Merja Penttilä

ABSTRACT We characterized the effect of deletion of the Trichoderma reesei (Hypocrea jecorina) ace1 gene encoding the novel cellulase regulator ACEI that was isolated based on its ability to bind to and activate in vivo in Saccharomyces cerevisiae the promoter of the main cellulase gene, cbh1. Deletion of ace1 resulted in an increase in the expression of all the main cellulase genes and two xylanase genes in sophorose- and cellulose-induced cultures, indicating that ACEI acts as a repressor of cellulase and xylanase expression. Growth of the strain with a deletion of the ace1 gene on different carbon sources was analyzed. On cellulose-based medium, on which cellulases are needed for growth, the Δace1 strain grew better than the host strain due to the increased cellulase production. On culture media containing sorbitol as the sole carbon source, the growth of the strain with a deletion of the ace1 gene was severely impaired, suggesting that ACEI regulates expression of other genes in addition to cellulase and xylanase genes. A strain with a deletion of the ace1 gene and with a deletion of the ace2 gene coding for the cellulase and xylanase activator ACEII expressed cellulases and xylanases similar to the Δace1 strain, indicating that yet another activator regulating cellulase and xylanase promoters was present.


2016 ◽  
Vol 39 (4) ◽  
pp. 1479-1494 ◽  
Author(s):  
Chunliang Xie ◽  
Li Yan ◽  
Wenbing Gong ◽  
Zuohua Zhu ◽  
Senwei Tan ◽  
...  

Background/Aims: Pleurotus eryngii is one of the most valued and delicious mushrooms which are commercially cultivated on various agro-wastes. How different substrates affect lignocellulosic biomass degradation, lignocellulosic enzyme production and biological efficiency in Pleurotus eryngii was unclear. Methods and Results: In this report, Pleurotus eryngii was cultivated in substrates including ramie stalks, kenaf stalks, cottonseed hulls and bulrush stalks. The results showed that ramie stalks and kenaf stalks were found to best suitable to cultivate Pleurotus eryngii with the biological efficiency achieved at 55% and 57%, respectively. In order to establish correlations between different substrates and lignocellulosic enzymes expression, the extracellular proteins from four substrates were profiled with high throughput TMT-based quantitative proteomic approach. 241 non-redundant proteins were identified and 74 high confidence lignocellulosic enzymes were quantified. Most of the cellulases, hemicellulases and lignin depolymerization enzymes were highly up-regulated when ramie stalks and kenaf stalks were used as carbon sources. The enzyme activities results suggested cellulases, hemicellulases and lignin depolymerization enzymes were significantly induced by ramie stalks and kenaf stalks. Conclusion: The lignocelluloses degradation, most of the lignocellulosic enzymes expressions and activities of Pleurotus eryngii had positive correlation with the biological efficiency, which depend on the nature of lignocellulosic substrates. In addition, the lignocellulosic enzymes expression profiles during Pleurotus eryngii growth in different substrates were obtained. The present study suggested that most of the lignocellulosic enzymes expressions and activities can be used as tools for selecting better performing substrates for commercial mushroom cultivation.


2019 ◽  
Author(s):  
Jacob J. Baker ◽  
Robert B. Abramovitch

AbstractMycobacterium tuberculosis (Mtb) establishes a state of non-replicating persistence when it is cultured at acidic pH with glycerol as a sole carbon source. Growth can be restored by spontaneous mutations in the ppe51 gene or supplementation with pyruvate, supporting that acid growth arrests is a genetically controlled, adaptive process and not simply a physiological limitation associated with acidic pH. Transcriptional profiling identified the methylcitrate synthase and methylcitrate dehydratase genes (prpC and prpD, respectively) as being selectively induced during acid growth arrest. prpCD along with isocitrate lyase (icl) enable Mtb to detoxify propionyl-CoA through the methylcitrate cycle. The goal of this study was to examine mechanisms underlying the regulation of prpCD during acid growth arrest. Induction of prpCD during acid growth arrest was reduced when the medium was supplemented with vitamin B12 (which enables an alternative propionate detoxification pathway) and enhanced in an icl mutant (which is required for the propionate detoxification), suggesting that Mtb is responding to elevated levels of propionyl-CoA during acidic growth arrest. We hypothesized that an endogenous source of propionyl-CoA generated during metabolism of methyl-branched lipids may be regulating prpCD. Using Mtb radiolabeled with 14C-propionate or 14C-acetate, it was observed that lipids are remodeled during acid growth arrest, with triacylglycerol being catabolized and sulfolipid and trehalose dimycolate being synthesized. Blocking TAG lipolysis using the lipase inhibitor tetrahydrolipstatin, resulted in enhanced prpC induction during acid growth arrest, suggesting that lipid remodeling may function, in part, to detoxify propionate. Notably, prpC was not induced during acid growth arrest when using lactate instead of glycerol. We propose that metabolism of glycerol at acidic pH may result in the accumulation of propionyl-CoA and that lipid remodeling may function as a detoxification mechanism.ImportanceDuring infection, Mycobacterium tuberculosis (Mtb) colonizes acidic environments, such as the macrophage phagosome and granuloma. Understanding regulatory and metabolic adaptations that occur in response to acidic pH can provide insights int0 mechanisms used by the bacterium to adapt to the host. We have previously shown that Mtb exhibits pH-dependent metabolic adaptations and requires anaplerotic enzymes, such as Icl1/2 and PckA, to grow optimally at acidic pH. Additionally, we have observed that Mtb can only grow on specific carbon sources at acidic pH. Together these findings show that Mtb integrates environmental pH and carbon source to regulate its metabolism. In this study, it is shown that Mtb remodels its lipids and modulates the expression of propionyl-CoA detoxifying genes prpCD when grown on glycerol at acidic pH. This finding suggests that lipid remodeling at acidic pH may contribute to detoxification of propionyl-CoA, by incorporating the metabolite into methyl-branched cell envelope lipids.


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