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The Hypocrea jecorina (Trichoderma reesei) hypercellulolytic mutant RUT C30 lacks a 85 kb (29 gene-encoding) region of the wild-type genome.

Seidl V, Gamauf C, Druzhinina IS, Seiboth B, Hartl L, Kubicek CP - BMC Genomics (2008)

Bottom Line: The mutation of the cre1 locus has specifically occurred in RUT C30.Some of the genes that are lacking in RUT C30 could be correlated with pronounced alterations in its phenotype, such as poor growth on alpha-linked oligo- and polyglucosides (loss of maltose permease), or disturbance of osmotic homeostasis.Our data place a general caveat on the use of H. jecorina RUT C30 for further basic research.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166-5, A-1060 Wien, Austria. vseidl@mail.zserv.tuwien.ac.at

ABSTRACT

Background: The hypercellulolytic mutant Hypocrea jecorina (anamorph Trichoderma reesei) RUT C30 is the H. jecorina strain most frequently used for cellulase fermentations and has also often been employed for basic research on cellulase regulation. This strain has been reported to contain a truncated carbon catabolite repressor gene cre1 and is consequently carbon catabolite derepressed. To date this and an additional frame-shift mutation in the glycoprotein-processing beta-glucosidase II encoding gene are the only known genetic differences in strain RUT C30.

Results: In the present paper we show that H. jecorina RUT C30 lacks an 85 kb genomic fragment, and consequently misses additional 29 genes comprising transcription factors, enzymes of the primary metabolism and transport proteins. This loss is already present in the ancestor of RUT C30--NG 14--and seems to have occurred in a palindromic AT-rich repeat (PATRR) typically inducing chromosomal translocations, and is not linked to the cre1 locus. The mutation of the cre1 locus has specifically occurred in RUT C30. Some of the genes that are lacking in RUT C30 could be correlated with pronounced alterations in its phenotype, such as poor growth on alpha-linked oligo- and polyglucosides (loss of maltose permease), or disturbance of osmotic homeostasis.

Conclusion: Our data place a general caveat on the use of H. jecorina RUT C30 for further basic research.

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Related in: MedlinePlus

Pedigree of strain H. jecorina RUT C30 and its relationship to the wild-type isolate QM6a. Mutations into the strains were introduced by UV-light (UV), nitrosoguanidine (NTG) or linear accelerator (LA). The lineage leading to strain QM 9414 is also shown for comparison.
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Figure 1: Pedigree of strain H. jecorina RUT C30 and its relationship to the wild-type isolate QM6a. Mutations into the strains were introduced by UV-light (UV), nitrosoguanidine (NTG) or linear accelerator (LA). The lineage leading to strain QM 9414 is also shown for comparison.

Mentions: In modern biotechnology, many of the fermentations producing high volume/low price products make use of microbial strains which have been improved by classical mutagenesis using UV light or mutagenic chemicals. Information about the loci which became altered in the process of mutation and selection for improved product formation is scarce, if available at all. One notable exception is penicillin production by the fungus Penicillium chrysogenum [1-3], where the early mutation program has been shown to have removed detoxification reactions for the side chain precursor and has increased the biosynthetic capacity by amplification of the gene cluster for its production. In the case of the industrial cellulase producing fungus Trichoderma reesei, the anamorph of the pantropical ascomycete Hypocrea jecorina, all of the strains that are currently used on a commercial scale have been ultimately derived from one single isolate which was collected on the Solomon Islands during World War II [4,5]. The genetic basis of the respective mutations which led to enhanced cellulase production in these industrial strains is essentially unknown. However, B.S. Montenecourt and D.E. Eveleigh prepared two separate lines of mutants which led to the hypercellulolytic strains RUT C30 and RL-P37 ([5]; Fig. 1), of which H. jecorina RUT C30 has become the most frequently used strain for laboratory cellulase production [6-11]. In this strain two of its genetic changes have been described: one is a truncation in the cre1 gene encoding CRE1 the carbon catabolite repressor protein, which renders this strain carbon catabolite derepressed [12]; and another one leading to a frameshift mutation in the glycoprotein processing β-glucosidase II encoding gene [13]. Electrophoretic karyotyping showed that the two largest chromosomes in RUT C30 are somewhat smaller, whereas the other five chromosomes are somewhat larger, resulting in a total increase in genome size from 32.5 to 34.7 Mbps [14]. Gene mapping revealed a history of significant recombination events between the seven chromosomes, but no gene losses were observed so far [14,15]. The only exception that was noted was the absence of hybridization of one random clone (RC16) in RUT C30, which hybridized to chromosome IV in strain QM6a and chromosome I in strain QM9414 [14]. This suggests the presence of many more changes in RUT C30, which have not been uncovered until today.


The Hypocrea jecorina (Trichoderma reesei) hypercellulolytic mutant RUT C30 lacks a 85 kb (29 gene-encoding) region of the wild-type genome.

Seidl V, Gamauf C, Druzhinina IS, Seiboth B, Hartl L, Kubicek CP - BMC Genomics (2008)

Pedigree of strain H. jecorina RUT C30 and its relationship to the wild-type isolate QM6a. Mutations into the strains were introduced by UV-light (UV), nitrosoguanidine (NTG) or linear accelerator (LA). The lineage leading to strain QM 9414 is also shown for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2483294&req=5

Figure 1: Pedigree of strain H. jecorina RUT C30 and its relationship to the wild-type isolate QM6a. Mutations into the strains were introduced by UV-light (UV), nitrosoguanidine (NTG) or linear accelerator (LA). The lineage leading to strain QM 9414 is also shown for comparison.
Mentions: In modern biotechnology, many of the fermentations producing high volume/low price products make use of microbial strains which have been improved by classical mutagenesis using UV light or mutagenic chemicals. Information about the loci which became altered in the process of mutation and selection for improved product formation is scarce, if available at all. One notable exception is penicillin production by the fungus Penicillium chrysogenum [1-3], where the early mutation program has been shown to have removed detoxification reactions for the side chain precursor and has increased the biosynthetic capacity by amplification of the gene cluster for its production. In the case of the industrial cellulase producing fungus Trichoderma reesei, the anamorph of the pantropical ascomycete Hypocrea jecorina, all of the strains that are currently used on a commercial scale have been ultimately derived from one single isolate which was collected on the Solomon Islands during World War II [4,5]. The genetic basis of the respective mutations which led to enhanced cellulase production in these industrial strains is essentially unknown. However, B.S. Montenecourt and D.E. Eveleigh prepared two separate lines of mutants which led to the hypercellulolytic strains RUT C30 and RL-P37 ([5]; Fig. 1), of which H. jecorina RUT C30 has become the most frequently used strain for laboratory cellulase production [6-11]. In this strain two of its genetic changes have been described: one is a truncation in the cre1 gene encoding CRE1 the carbon catabolite repressor protein, which renders this strain carbon catabolite derepressed [12]; and another one leading to a frameshift mutation in the glycoprotein processing β-glucosidase II encoding gene [13]. Electrophoretic karyotyping showed that the two largest chromosomes in RUT C30 are somewhat smaller, whereas the other five chromosomes are somewhat larger, resulting in a total increase in genome size from 32.5 to 34.7 Mbps [14]. Gene mapping revealed a history of significant recombination events between the seven chromosomes, but no gene losses were observed so far [14,15]. The only exception that was noted was the absence of hybridization of one random clone (RC16) in RUT C30, which hybridized to chromosome IV in strain QM6a and chromosome I in strain QM9414 [14]. This suggests the presence of many more changes in RUT C30, which have not been uncovered until today.

Bottom Line: The mutation of the cre1 locus has specifically occurred in RUT C30.Some of the genes that are lacking in RUT C30 could be correlated with pronounced alterations in its phenotype, such as poor growth on alpha-linked oligo- and polyglucosides (loss of maltose permease), or disturbance of osmotic homeostasis.Our data place a general caveat on the use of H. jecorina RUT C30 for further basic research.

View Article: PubMed Central - HTML - PubMed

Affiliation: Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166-5, A-1060 Wien, Austria. vseidl@mail.zserv.tuwien.ac.at

ABSTRACT

Background: The hypercellulolytic mutant Hypocrea jecorina (anamorph Trichoderma reesei) RUT C30 is the H. jecorina strain most frequently used for cellulase fermentations and has also often been employed for basic research on cellulase regulation. This strain has been reported to contain a truncated carbon catabolite repressor gene cre1 and is consequently carbon catabolite derepressed. To date this and an additional frame-shift mutation in the glycoprotein-processing beta-glucosidase II encoding gene are the only known genetic differences in strain RUT C30.

Results: In the present paper we show that H. jecorina RUT C30 lacks an 85 kb genomic fragment, and consequently misses additional 29 genes comprising transcription factors, enzymes of the primary metabolism and transport proteins. This loss is already present in the ancestor of RUT C30--NG 14--and seems to have occurred in a palindromic AT-rich repeat (PATRR) typically inducing chromosomal translocations, and is not linked to the cre1 locus. The mutation of the cre1 locus has specifically occurred in RUT C30. Some of the genes that are lacking in RUT C30 could be correlated with pronounced alterations in its phenotype, such as poor growth on alpha-linked oligo- and polyglucosides (loss of maltose permease), or disturbance of osmotic homeostasis.

Conclusion: Our data place a general caveat on the use of H. jecorina RUT C30 for further basic research.

Show MeSH
Related in: MedlinePlus