scholarly journals Insertion of the LINE Retrotransposon MGL Causes a Conidiophore Pattern Mutation in Magnaporthe grisea

2000 ◽  
Vol 13 (8) ◽  
pp. 892-894 ◽  
Author(s):  
Marie Nishimura ◽  
Nagao Hayashi ◽  
Nam-Soo Jwa ◽  
Gee W. Lau ◽  
John E. Hamer ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Aspergillus Nidulans ◽  
Insertional Mutagenesis ◽  
Magnaporthe Grisea ◽  
Morphological Mutants

We obtained three Magnaporthe grisea morphological mutants that had the LINE transposon MGL inserted into the ACR1 locus. Sequence analysis revealed that ACR1 is homologous to medA, a developmental regulator of Aspergillus nidulans conidiation. These results demonstrated that MGL elements could transpose and cause insertional mutagenesis in M. grisea.

scholarly journals The Aspergillus nidulans xprF Gene Encodes a Hexokinase-like Protein Involved in the Regulation of Extracellular Proteases

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1559-1571 ◽  
Author(s):  
Margaret E Katz ◽  
Amir Masoumi ◽  
Stephen R Burrows ◽  
Carolyn G Shirtliff ◽  
Brian F Cheetham
Keyword(s):  
Sequence Analysis ◽  
Aspergillus Nidulans ◽  
Carbon Limitation ◽  
Extracellular Proteases ◽  
Nonsense Mutations ◽  
Acid Protein ◽  
Catalytic Role ◽  
New Type ◽  
Protease Deficient ◽  
A Minor

Abstract The extracellular proteases of Aspergillus nidulans are produced in response to limitation of carbon, nitrogen, or sulfur, even in the absence of exogenous protein. Mutations in the A. nidulans xprF and xprG genes have been shown to result in elevated levels of extracellular protease in response to carbon limitation. The xprF gene was isolated and sequence analysis indicates that it encodes a 615-amino-acid protein, which represents a new type of fungal hexokinase or hexokinase-like protein. In addition to their catalytic role, hexokinases are thought to be involved in triggering carbon catabolite repression. Sequence analysis of the xprF1 and xprF2 alleles showed that both alleles contain nonsense mutations. No loss of glucose or fructose phosphorylating activity was detected in xprF1 or xprF2 mutants. There are two possible explanations for this observation: (1) the xprF gene may encode a minor hexokinase or (2) the xprF gene may encode a protein with no hexose phosphorylating activity. Genetic evidence suggests that the xprF and xprG genes are involved in the same regulatory pathway. Support for this hypothesis was provided by the identification of a new class of xprG- mutation that suppresses the xprF1 mutation and results in a protease-deficient phenotype.

Tagging quantitative loci controlling pathogenicity in Magnaporthe grisea by insertional mutagenesis

2002 ◽  
Vol 61 (2) ◽  
pp. 77-88 ◽  
Author(s):  
D. Fujimoto ◽  
Y. Shi ◽  
D. Christian ◽  
J.B. Mantanguihan ◽  
H. Leung
Keyword(s):  
Insertional Mutagenesis ◽  
Magnaporthe Grisea

scholarly journals Reduced viscosity mutants of Trichoderma reesei with improved industrial fermentation characteristics

2021 ◽  
Author(s):  
Elizabeth Bodie ◽  
Aleksandra Virag ◽  
Robert J Pratt ◽  
Nicholas Leiva ◽  
Michael Ward ◽  
...  
Keyword(s):  
Trichoderma Reesei ◽  
Insertional Mutagenesis ◽  
Biomass Concentration ◽  
Volumetric Productivity ◽  
Specific Productivity ◽  
Secreted Protein ◽  
Single Strain ◽  
Reduced Viscosity ◽  
High Specific Productivity ◽  
Morphological Mutants

Abstract Morphological mutants of Trichoderma reesei were isolated following chemical or insertional mutagenesis. The mutant strains were shown to have reduced viscosity under industrially-relevant fermentation conditions and to have maintained high specific productivity of secreted protein. This allowed higher biomass concentration to be maintained during the production phase and, consequently, increased volumetric productivity of secreted protein. The causative mutations were traced to four individual genes (designated sfb3, ssb7, seb1 and mpg1). We showed that two of the morphological mutations could be combined in a single strain to further reduce viscosity and enable a 100 per cent increase in volumetric productivity.

scholarly journals Transposon impala, a Novel Tool for Gene Tagging in the Rice Blast Fungus Magnaporthe grisea

2001 ◽  
Vol 14 (3) ◽  
pp. 308-315 ◽  
Author(s):  
François Villalba ◽  
Marc-Henri Lebrun ◽  
Aurélie Hua-Van ◽  
Marie-Josée Daboussi ◽  
Marie-Claire Grosjean-Cournoyer
Keyword(s):  
Nitrate Reductase ◽  
Fusarium Oxysporum ◽  
Rice Blast ◽  
Insertional Mutagenesis ◽  
Magnaporthe Grisea ◽  
Rice Blast Fungus ◽  
Single Copy ◽  
Wild Type ◽  
Type Locus ◽  
Blast Fungus

impala, a Tc1-mariner transposable element from Fusarium oxysporum, was introduced into the rice blast fungus Magnaporthe grisea to develop transposon-based insertional mutagenesis. A construct (pNIL160) containing an autonomous impala copy inserted in the promoter of niaD encoding Aspergillus nidulans nitrate reductase was introduced by transformation into a M. grisea nitrate reductase-deficient mutant. impala excision was monitored by restoration of prototrophy for nitrate. Southern analysis of niaD+ revertants revealed that impala was able to excise and reinsert at new loci in M. grisea. As observed for its host Fusarium oxysporum, impala inserted at a TA site left a typical excision footprint of 5 bp. We have shown that a defective impala copy was inactive in M. grisea, yet it can be activated by a functional impala transposase. A transformant carrying a single copy of pNIL160 was used to generate a collection of 350 revertants. Mutants either altered for their mycelial growth (Rev2) or nonpathogenic (Rev77) were obtained. Complementation of Rev77 with a 3-kb genomic fragment from a wild-type locus was successful, demonstrating the tagging of a pathogenicity gene by impala. This gene, called ORP1, is essential for penetration of host leaves by M. grisea and has no sequence homology to known genes.

scholarly journals Identification of Pathogenicity Mutants of the Rice Blast Fungus Magnaporthe grisea by Insertional Mutagenesis

1999 ◽  
Vol 12 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Pascale V. Balhadère ◽  
Andrew J. Foster ◽  
Nicholas J. Talbot
Keyword(s):  
Insertional Mutagenesis ◽  
Magnaporthe Grisea ◽  
Single Gene ◽  
Phenotypic Analysis ◽  
Dependent Protein Kinase ◽  
Dna Integration ◽  
Gene Segregation ◽  
Similar Phenotype ◽  
Dependent Protein ◽  
Remi Mutagenesis

Restriction enzyme-mediated DNA integration (REMI) mutagenesis was used to identify mutants of Magnaporthe grisea impaired in pathogenicity. Three REMI protocols were evaluated and the frequency of REMIs determined. An REMI library of 3,527 M. grisea transformants was generated in three genetic backgrounds, and 1,150 transformants were screened for defects in pathogenicity with a barley cut leaf assay. Five mutants were identified and characterized. Two mutants (2029 and 2050) were impaired in appressorium function. Two other mutants, 125 and 130, were altered in conidial morphology, conidiogenesis, and appressorium function. Mutant 130 was also a methionine auxotroph and methionine auxotrophy co-segregated with the reduction in pathogenicity. An additional mutant, 80, showed reduced pathogenicity on blast-susceptible rice cultivars but was fully pathogenic on barley. The reduction of pathogenicity in mutant 80 was associated with a delay in conidial germination and appressorium development. Genetic analysis suggested single-gene segregation for each mutant, but only two of the mutations co-segregated with the hygromycin resistance marker. The genetic loci in mutants 2029, 2050, 125, 130, and 80 were termed PDE1, PDE2, IGD1, MET1, and GDE1, respectively. pde1 and pde2 were non-allelic to cpkA, a mutation in the catalytic subunit of cyclic AMP (cAMP)-dependent protein kinase A with a very similar phenotype. The results indicate the utility of REMI for studying fungal pathogenicity, but also highlight the requirement for rigorous genetic and phenotypic analysis.

scholarly journals DETECTION AND IDENTIFICATION OF TRANSLOCATIONS BY INCREASED SPECIFIC NONDISJUNCTION IN ASPERGILLUS NIDULANS

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 19-31
Author(s):  
Alan Upshall ◽  
Etta Käfer
Keyword(s):  
Aspergillus Nidulans ◽  
Genetic Factors ◽  
Visual Detection ◽  
Control Level ◽  
Linkage Groups ◽  
Detection And Identification ◽  
Induced Mutants ◽  
Morphological Mutants ◽  
Average Control ◽  
Heterozygous Translocation

ABSTRACT A meiotic technique for visual detection of translocations has been applied to ten mitotically identified interchanges, and three new translocations were discovered using this method. Testcrosses between "standard" strains and potential translocation strains—e.g. strains with newly induced mutants or descendants from translocation crosses—are inspected for the frequency of abnormal-looking colonies. In all heterozygous translocation crosses "abnormals" are increased at least tenfold compared to the average control level of 0.15%. Most of these are disomics, and can be recognized by their characteristic phenotypes. Each translocation produces a few specific types, since nondisjunction is increased mainly in the linkage groups involved in the translocation (50–100-fold over control values). Therefore, translocations were not only detected but often tentatively assigned to linkage groups from the analysis of the disomic progeny in crosses. In addition, this technique allows reciprocal and nonreciprocal translocations to be distinguished, since only the latter produce one-third phenotypically abnormal duplication progeny. While results are clearcut in most cases, occasionally problems are encountered, e.g. when morphological mutants segregate in crosses, or when other genetic factors which increase or reduce the frequency of nondisjunction are present in certain strains.

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