Lactose metabolism and cellulase production in Hypocrea jecorina: the gal7 gene, encoding galactose-1-phosphate uridylyltransferase, is essential for growth on galactose but not for cellulase induction

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.

Download Full-text

Role of the bga1-Encoded Extracellular β-Galactosidase of Hypocrea jecorina in Cellulase Induction by Lactose

Applied and Environmental Microbiology ◽

10.1128/aem.71.2.851-857.2005 ◽

2005 ◽

Vol 71 (2) ◽

pp. 851-857 ◽

Cited By ~ 45

Author(s):

Bernhard Seiboth ◽

Lukas Hartl ◽

Noora Salovuori ◽

Karin Lanthaler ◽

Geoff D. Robson ◽

...

Keyword(s):

Amino Acid ◽

Signal Sequence ◽

Glycosyl Hydrolase ◽

Cellulase Production ◽

Lag Phase ◽

Galactosidase Activity ◽

Hypocrea Jecorina ◽

Cellobiohydrolase I ◽

Cellulase Induction

ABSTRACT Lactose is the only soluble and economically feasible carbon source for the production of cellulases or heterologous proteins regulated by cellulase expression signals by Hypocrea jecorina (Trichoderma reesei). We investigated the role of the major β-galactosidase of H. jecorina in lactose metabolism and cellulase induction. A genomic copy of the bga1 gene was cloned, and this copy encodes a 1,023-amino-acid protein with a 20-amino-acid signal sequence. This protein has a molecular mass of 109.3 kDa, belongs to glycosyl hydrolase family 35, and is the major extracellular β-galactosidase during growth on lactose. Its transcript was abundant during growth on l-arabinose and l-arabinitol but was much less common when the organism was grown on lactose, d-galactose, galactitol, d-xylose, and xylitol. Δbga1 strains grow more slowly and accumulate less biomass on lactose, but the cellobiohydrolase I and II gene expression and the final cellulase yields were comparable to those of the parental strain. Overexpression of bga1 under the control of the pyruvate kinase promoter reduced the lag phase, increased growth on lactose, and limited transcription of cellobiohydrolases. We detected an additional extracellular β-galactosidase activity that was not encoded by bga1 but no intracellular β-galactosidase activity. In conclusion, cellulase production on lactose occurs when β-galactosidase activity levels are low but decreases as the β-galactosidase activities increase. The data indicate that bga1-encoded β-galactosidase activity is a critical factor for cellulase production on lactose.

Download Full-text

How Carbon Source and Degree of Oligosaccharide Polymerization Affect Production of Cellulase-Degrading Enzymes by Fusarium oxysporum f. sp. lycopersici

Frontiers in Microbiology ◽

10.3389/fmicb.2021.652655 ◽

2021 ◽

Vol 12 ◽

Author(s):

Nasim Najjarzadeh ◽

Leonidas Matsakas ◽

Ulrika Rova ◽

Paul Christakopoulos

Keyword(s):

Carbon Source ◽

Fusarium Oxysporum ◽

Filamentous Fungi ◽

Cellulase Production ◽

Degree Of Polymerization ◽

Cellulase Induction ◽

Degrading Enzymes

Cellulases are a group of enzymes responsible for the degradation of cellulose, which is one of the most abundant polymers on Earth. The three main groups of cellulases are endoglucosidases, exoglucosidases, and β-glucosidases; however, the mechanism of induction of these enzymes remains poorly characterized. Cellooligosaccharides are among the main inducers of these enzymes in filamentous fungi, yet it is not clear how their degree of polymerization may affect the strength of induction. In the present study, we investigated the effect of different carbohydrate-based inducers, such as lactose, sophorose, cellooligosaccharides, and xylooligosacharides, characterized by different concentrations and degree of polymerization, on cellulases production by the fungus Fusarium oxysporum f. sp. lycopersici, which is one of the most studied lignocellulose degrading fungi with the ability to consume both cellulose and hemicellulose. Moreover, the effect of carbon source on cellulase induction was assessed by growing the biomass on sucrose or glycerol. Results showed a correlation between induction efficiency and the cellooligosaccharides’ concentration and size, as well as the carbon source available. Specifically, cellotetraose was a better inducer when sucrose was the carbon source, while cellobiose yielded a better result on glycerol. These findings can help optimize industrial cellulase production.

Download Full-text

Sophorolipids-induced cellulase production in cocultures of Hypocrea jecorina Rut C30 and Candida bombicola

Enzyme and Microbial Technology ◽

10.1016/j.enzmictec.2008.10.006 ◽

2009 ◽

Vol 44 (2) ◽

pp. 107-111 ◽

Cited By ~ 15

Author(s):

Chi-Ming Lo ◽

Lu-Kwang Ju

Keyword(s):

Cellulase Production ◽

Candida Bombicola ◽

Hypocrea Jecorina ◽

Rut C30

Download Full-text

Systems Analysis of Lactose Metabolism in Trichoderma reesei Identifies a Lactose Permease That Is Essential for Cellulase Induction

PLoS ONE ◽

10.1371/journal.pone.0062631 ◽

2013 ◽

Vol 8 (5) ◽

pp. e62631 ◽

Cited By ~ 82

Author(s):

Christa Ivanova ◽

Jenny A. Bååth ◽

Bernhard Seiboth ◽

Christian P. Kubicek

Keyword(s):

Trichoderma Reesei ◽

Systems Analysis ◽

Lactose Permease ◽

Cellulase Induction ◽

Lactose Metabolism

Download Full-text

Studies on sugar transporter CRT1 reveal new characteristics that are critical for cellulase induction in Trichoderma reesei

Biotechnology for Biofuels ◽

10.1186/s13068-020-01797-7 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Sami Havukainen ◽

Mari Valkonen ◽

Kari Koivuranta ◽

Christopher P. Landowski

Keyword(s):

Trichoderma Reesei ◽

Genome Annotation ◽

Cellulase Production ◽

Fungal Species ◽

Extracellular Proteins ◽

Sugar Transporter ◽

Sugar Transporters ◽

Cellulase Induction ◽

The Many ◽

Rut C30

Abstract Background Trichoderma reesei is an ascomycete fungus that has a tremendous capability of secreting extracellular proteins, mostly lignocellulose-degrading enzymes. Although many aspects of the biology of this organism have been unfolded, the roles of the many sugar transporters coded in its genome are still a mystery with a few exceptions. One of the most interesting sugar transporters that has thus far been discovered is the cellulose response transporter 1 (CRT1), which has been suggested to be either a sugar transporter or a sensor due to its seemingly important role in cellulase induction. Results Here we show that CRT1 is a high-affinity cellobiose transporter, whose function can be complemented by the expression of other known cellobiose transporters. Expression of two sequence variants of the crt1 gene in Saccharomyces cerevisiae revealed that only the variant listed in the RUT-C30 genome annotation has the capability to transport cellobiose and lactose. When expressed in the $$\Delta$$ Δ crt1 strain, the variant listed in the QM6a genome annotation offers partial complementation of the cellulase induction, while the expression of the RUT-C30 variant or cellobiose transporters from two other fungal species fully restore the cellulase induction. Conclusions These results add to our knowledge about the fungal metabolism of cellulose-derived oligosaccharides, which have the capability of inducing the cellulase production in many species. They also help us to deepen our understanding of the T. reesei lactose metabolism, which can have important consequences as this sugar is used as the inducer of protein secretion in many industrial processes which employ this species.

Download Full-text

Overexpression of the Gene Encoding GTP:Mannose-1-Phosphate Guanyltransferase, mpg1, Increases Cellular GDP-Mannose Levels and Protein Mannosylation in Trichoderma reesei

Applied and Environmental Microbiology ◽

10.1128/aem.69.8.4383-4389.2003 ◽

2003 ◽

Vol 69 (8) ◽

pp. 4383-4389 ◽

Cited By ~ 17

Author(s):

Anna Zakrzewska ◽

Grazyna Palamarczyk ◽

Hubert Krotkiewski ◽

Ewa Zdebska ◽

Markku Saloheimo ◽

...

Keyword(s):

Trichoderma Reesei ◽

Protein Secretion ◽

Protein Glycosylation ◽

Secreted Proteins ◽

Regulatory Role ◽

Limiting Factors ◽

Hypocrea Jecorina ◽

Gene Encoding ◽

Twofold Increase ◽

Dolichyl Phosphate

ABSTRACT To elucidate the regulation and limiting factors in the glycosylation of secreted proteins, the mpg1 and dpm1 genes from Trichoderma reesei (Hypocrea jecorina) encoding GTP:α-d-mannose-1-phosphate guanyltransferase and dolichyl phosphate mannose synthase (DPMS), respectively, were overexpressed in T. reesei. No significant increases were observed in DPMS activity or protein secretion in dpm1-overexpressing transformants, whereas overexpression of mpg1 led to a twofold increase in GDP-mannose (GDPMan) levels. GDPMan was effectively utilized by mannnosyltransferases and resulted in hypermannosylation of secreted proteins in both N and O glycosylation. Overexpression of the mpg1 gene also increased the transcription of the dpm1 gene and DPMS activity. Our data indicate that the level of cellular GDPMan can play a major regulatory role in protein glycosylation in T. reesei.

Download Full-text