Identification ofvib-1, a Locus Involved in Vegetative Incompatibility Mediated byhet-cinNeurospora crassa

AbstractA non-self-recognition system called vegetative incompatibility is ubiquitous in filamentous fungi and is genetically regulated by het loci. Different fungal individuals are unable to form viable heterokaryons if they differ in allelic specificity at a het locus. To identify components of vegetative incompatibility mediated by allelic differences at the het-c locus of Neurospora crassa, we isolated mutants that suppressed phenotypic aspects of het-c vegetative incompatibility. Three deletion mutants were identified; the deletions overlapped each other in an ORF named vib-1 (vegetative incompatibility blocked). Mutations in vib-1 fully relieved growth inhibition and repression of conidiation conferred by het-c vegetative incompatibility and significantly reduced hyphal compartmentation and death rates. The vib-1 mutants displayed a profuse conidiation pattern, suggesting that VIB-1 is a regulator of conidiation. VIB-1 shares a region of similarity to PHOG, a possible phosphate nonrepressible acid phosphatase in Aspergillus nidulans. Native gel analysis of wild-type strains and vib-1 mutants indicated that vib-1 is not the structural gene for nonrepressible acid phosphatase, but rather may regulate nonrepressible acid phosphatase activity.

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HET-E and HET-D Belong to a New Subfamily of WD40 Proteins Involved in Vegetative Incompatibility Specificity in the Fungus Podospora anserina

Genetics ◽

10.1093/genetics/161.1.71 ◽

2002 ◽

Vol 161 (1) ◽

pp. 71-81

Author(s):

Eric Espagne ◽

Pascale Balhadère ◽

Marie-Louise Penin ◽

Christian Barreau ◽

Béatrice Turcq

Keyword(s):

Genetic Difference ◽

Podospora Anserina ◽

Wild Type ◽

Incompatible Interaction ◽

Vegetative Incompatibility ◽

Repeat Domain ◽

Upper Face ◽

E1a Gene ◽

Type Strains ◽

Wd40 Repeats

Abstract Vegetative incompatibility, which is very common in filamentous fungi, prevents a viable heterokaryotic cell from being formed by the fusion of filaments from two different wild-type strains. Such incompatibility is always the consequence of at least one genetic difference in specific genes (het genes). In Podospora anserina, alleles of the het-e and het-d loci control heterokaryon viability through genetic interactions with alleles of the unlinked het-c locus. The het-d2Y gene was isolated and shown to have strong similarity with the previously described het-e1A gene. Like the HET-E protein, the HET-D putative protein displayed a GTP-binding domain and seemed to require a minimal number of 11 WD40 repeats to be active in incompatibility. Apart from incompatibility specificity, no other function could be identified by disrupting the het-d gene. Sequence comparison of different het-e alleles suggested that het-e specificity is determined by the sequence of the WD40 repeat domain. In particular, the amino acids present on the upper face of the predicted β-propeller structure defined by this domain may confer the incompatible interaction specificity.

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Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

Molecular and Cellular Biology ◽

10.1128/mcb.12.9.3827 ◽

1992 ◽

Vol 12 (9) ◽

pp. 3827-3833 ◽

Cited By ~ 41

Author(s):

T H Adams ◽

W A Hide ◽

L N Yager ◽

B N Lee

Keyword(s):

Life Cycle ◽

Aspergillus Nidulans ◽

Optimal Growth ◽

Growth Conditions ◽

Nutrient Deprivation ◽

Deletion Mutants ◽

Wild Type ◽

Microbial Development ◽

Type Strains ◽

Posttranscriptional Level

In contrast to many other cases in microbial development, Aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation. Mutations in the acoD locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. We show that unlike wild-type strains, acoD deletion mutants are unable to make conidiophores under optimal growth conditions but can be induced to conidiate when growth is nutritionally limited. The requirement for acoD in conidiophore development occurs prior to activation of brlA, a primary regulator of development. The acoD transcript is present both in vegetative hyphae prior to developmental induction and in developing cultures. However, the effects of acoD mutations are detectable only after developmental induction. We propose that acoD activity is primarily controlled at the posttranscriptional level and that it is required to direct developmentally specific changes that bring about growth inhibition and activation of brlA expression to result in conidiophore development.

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Isolation of a gene required for programmed initiation of development by Aspergillus nidulans

Molecular and Cellular Biology ◽

10.1128/mcb.12.9.3827-3833.1992 ◽

1992 ◽

Vol 12 (9) ◽

pp. 3827-3833

Author(s):

T H Adams ◽

W A Hide ◽

L N Yager ◽

B N Lee

Keyword(s):

Life Cycle ◽

Aspergillus Nidulans ◽

Optimal Growth ◽

Growth Conditions ◽

Nutrient Deprivation ◽

Deletion Mutants ◽

Wild Type ◽

Microbial Development ◽

Type Strains ◽

Posttranscriptional Level

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Identification and Characterization of theNeisseria gonorrhoeaeMscS-Like Mechanosensitive Channel

Infection and Immunity ◽

10.1128/iai.00090-18 ◽

2018 ◽

Vol 86 (6) ◽

Cited By ~ 2

Author(s):

Zhemin Wang ◽

Xiaomin Wang ◽

Ping Lu ◽

Chunshan Ni ◽

Yuezhou Li ◽

...

Keyword(s):

Turgor Pressure ◽

Bacterial Pathogen ◽

Mechanosensitive Channel ◽

Infection Model ◽

Deletion Mutants ◽

Mechanosensitive Channels ◽

Wild Type ◽

Content Type ◽

Type Strains

ABSTRACTMechanosensitive channels are ubiquitous in bacteria and provide an essential mechanism to survive sudden exposure to a hypo-osmotic environment by the sensing and release of increased turgor pressure. No mechanosensitive channels have thus far been identified and characterized for the human-specific bacterial pathogenNeisseria gonorrhoeae. In this study, we identified and characterized theN. gonorrhoeaeMscS-like mechanosensitive channel (Ng-MscS). Electrophysiological analyses by the patch clamp method showed that Ng-MscS is stretch activated and contains pressure-dependent gating properties. Further mutagenesis studies of critical residues forming the hydrophobic vapor lock showed that gain-of-function mutations in Ng-MscS inhibited bacterial growth. Subsequent analysis of the function of Ng-MscS inN. gonorrhoeaeby osmotic down-shock assays revealed that the survival of Ng-mscSdeletion mutants was significantly reduced compared with that of wild-type strains, while down-shock survival was restored upon the ectopic complementation ofmscS. Finally, to investigate whether Ng-MscS is important forN. gonorrhoeaeduring infections, competition assays were performed by using a murine vaginal tract infection model. Ng-mscSdeletion mutants were outcompeted byN. gonorrhoeaewild-type strains for colonization and survival in this infection model, highlighting that Ng-MscS contributes toin vivocolonization and survival. Therefore, Ng-MscS might be a promising target for the future development of novel antimicrobials.

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Suppressors of recB mutations in Salmonella typhimurium.

Genetics ◽

10.1093/genetics/138.1.11 ◽

1994 ◽

Vol 138 (1) ◽

pp. 11-28 ◽

Cited By ~ 1

Author(s):

N R Benson ◽

J Roth

Keyword(s):

Escherichia Coli ◽

Salmonella Typhimurium ◽

Mitomycin C ◽

Ultraviolet Light ◽

Genetic Background ◽

Deletion Mutants ◽

Wild Type ◽

Insertion And Deletion ◽

Type Strains ◽

Tandem Duplications

Abstract Using a screen that directly assesses transductional proficiency, we have isolated suppressors of recB mutations in Salmonella typhimurium. The alleles of sbcB reported here are phenotypically distinct from those isolated in Escherichia coli in that they restore recombination proficiency (Rec+), resistance to ultraviolet light (UVR), and mitomycin C resistance (MCR) in the absence of an accompanying sbcCD mutation. In addition the sbcB alleles reported here are co-dominant to sbcB+. We have also isolated insertion and deletion mutants of the sbcB locus. These null mutations suppress only the UVS phenotype of recB mutants. We have also isolated sbcCD mutations, which map near proC. These sbcCD mutations increase the viability, recombination proficiency and MCR of both the transductional recombination suppressors (sbcB1 & sbcB6) and the sbcB null mutations. S. typhimurium recB sbcB1 sbcCD8 strains are 15-fold more recombination proficient than wild-type strains. The increase in transductants in these strains is accompanied by a loss of abortive transductants suggesting that these fragments are accessible to the mutant recombination apparatus. Using tandem duplications, we have constructed sbcB merodiploids and found that, in a recB mutant sbcCD+ genetic background, the sbcB+ allele is dominant to sbcB1 for transductional recombination but co-dominant for UVR and MCR. However, in a recB sbcCD8 genetic background, the sbcB1 mutation is co-dominant to sbcB+ for all phenotypes. Our results lead us to suggest that the SbcB and SbcCD proteins have roles in RecBCD-dependent recombination.

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Phosphatases ofCoprinus lagopus: the conditions for their production and the genetics of the alkaline phosphatase

Genetics Research ◽

10.1017/s0016672300012556 ◽

1971 ◽

Vol 18 (2) ◽

pp. 153-166 ◽

Cited By ~ 11

Author(s):

Jane North ◽

D. Lewis

Keyword(s):

Alkaline Phosphatase ◽

Acid Phosphatase ◽

Inorganic Phosphate ◽

Aerial Mycelium ◽

Wild Type ◽

Complementation Groups ◽

Phosphate Source ◽

Type Strains ◽

Phosphate Medium ◽

High Phosphate

SUMMARY1.Coprinus lagopusproduces two non-specific phosphatases: a constitutive acid phosphatase, and an alkaline phosphatase which is repressed during growth on media with a high inorganic phosphate concentration.2. The alkaline phosphatase is also repressed whenCoprinusis grown on an organic phosphate source; but if the acid phosphatase is selectively inhibited by fluoride the alkaline phosphatase is de-repressed and growth is comparable to that observed on an inorganic phosphate source.3. Alkaline phosphatase is not repressed in aerial mycelium or sporophores even when grown on high phosphate medium.4. Mutants altered in their capacity to synthesize alkaline phosphatase were selected from two compatible wild-type strains, H2 and H5.5. Mutants producing a higher level of alkaline phosphatase than wild-type (‘regulator’ mutants) fall into four (or possibly five) complementation groups. Assuming five separate genes, two pairs are linked; the remaining one is independent and on another chromosome.6. Mutants deficient in alkaline phosphatase synthesis fall into at least three groups. They were tested for linkage to ‘regulator’ loci but so far there is no evidence of this.

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Differentiation of RotaTeq ® vaccine strains from wild-type strains using NSP3 gene in reverse transcription polymerase chain reaction assay

Journal of Virological Methods ◽

10.1016/j.jviromet.2016.08.022 ◽

2016 ◽

Vol 237 ◽

pp. 72-78 ◽

Cited By ~ 3

Author(s):

Sunyoung Jeong ◽

Van Thai Than ◽

Inseok Lim ◽

Wonyong Kim

Keyword(s):

Polymerase Chain Reaction ◽

Reverse Transcription ◽

Polymerase Chain Reaction Assay ◽

Wild Type ◽

Chain Reaction ◽

Polymerase Chain ◽

Type Strains ◽

Nsp3 Gene

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Multilocus Self-Recognition Systems in Fungi as a Cause of Trans-Species Polymorphism

Genetics ◽

10.1093/genetics/161.2.633 ◽

2002 ◽

Vol 161 (2) ◽

pp. 633-641

Author(s):

Christina A Muirhead ◽

N Louise Glass ◽

Montgomery Slatkin

Keyword(s):

Genetic Model ◽

Balancing Selection ◽

Infectious Agents ◽

Vegetative Compatibility Group ◽

Vegetative Incompatibility ◽

Hyphal Fusion ◽

Self Recognition ◽

Compatibility Group ◽

Incompatibility Alleles ◽

Recognition Systems

Abstract Trans-species polymorphism, meaning the presence of alleles in different species that are more similar to each other than they are to alleles in the same species, has been found at loci associated with vegetative incompatibility in filamentous fungi. If individuals differ at one or more of these loci (termed het for heterokaryon), they cannot form stable heterokaryons after vegetative fusion. At the het-c locus in Neurospora crassa and related species there is clear evidence of trans-species polymorphism: three alleles have persisted for ∼30 million years. We analyze a population genetic model of multilocus vegetative incompatibility and find the conditions under which trans-species polymorphism will occur. In the model, several unlinked loci determine the vegetative compatibility group (VCG) of an individual. Individuals of different VCGs fail to form productive heterokaryons, while those of the same VCG form viable heterokaryons. However, viable heterokaryon formation between individuals of the same VCG results in a loss in fitness, presumably via transfer of infectious agents by hyphal fusion or exploitation by aggressive genotypes. The result is a form of balancing selection on all loci affecting an individual's VCG. We analyze this model by making use of a Markov chain/strong selection, weak mutation (SSWM) approximation. We find that trans-species polymorphism of the type that has been found at the het-c locus is expected to occur only when the appearance of new incompatibility alleles is strongly constrained, because the rate of mutation to such alleles is very low, because the number of possible incompatibility alleles at each locus is restricted, or because the number of incompatibility loci is limited.

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Influences of Histone Stoichiometry on the Target Site Preference of Retrotransposons Ty1 and Ty2 in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.3.761 ◽

1996 ◽

Vol 142 (3) ◽

pp. 761-776 ◽

Cited By ~ 2

Author(s):

Lori A Rinckel ◽

David J Garfinkel

Keyword(s):

Saccharomyces Cerevisiae ◽

Promoter Region ◽

Target Site ◽

Site Preference ◽

Wild Type ◽

Histone Proteins ◽

Protein Levels ◽

In The Wild ◽

Type Strains ◽

Orientation Bias

Abstract In Saccharomyces cerevisiae, the target site specificity of the retrotransposon Ty1 appears to involve the Ty integration complex recognizing chromatin structures. To determine whether changes in chromatin structure affect Ty1 and Ty2 target site preference, we analyzed Ty transposition at the CAN1 locus in mutants containing altered levels of histone proteins. A Δhta1-htb1 mutant with decreased levels of H2A and H2B histone proteins showed a pattern of Ty1 and Ty2 insertions at CAN1 that was significantly different from that of both the wild-type and a Δhta2-htb2 mutant, which does not have altered histone protein levels. Altered levels of H2A and H2B proteins disrupted a dramatic orientation bias in the CAN1 promoter region. In the wild-type strains, few Ty1 and Ty2 insertions in the promoter region were oriented opposite to the direction of CAN1 transcription. In the Δhta1-htb1 background, however, numerous Ty1 and Ty2 insertions were in the opposite orientation clustered within the TATA region. This altered insertion pattern does not appear to be due to a bias caused by selecting canavanine resistant isolates in the different HTA1-HTB1 backgrounds. Our results suggest that reduced levels of histone proteins alter Ty target site preference and disrupt an asymmetric Ty insertion pattern.

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Development of mutants of Gliocladium virens tolerant to benomyl

Canadian Journal of Microbiology ◽

10.1139/m90-084 ◽

1990 ◽

Vol 36 (7) ◽

pp. 484-489 ◽

Cited By ~ 12

Author(s):

G. C. Papavizas ◽

D. P. Roberts ◽

K. K. Kim

Keyword(s):

Carbon Source ◽

Type Strain ◽

Wild Type Strain ◽

Carbon Sources ◽

Sclerotium Rolfsii ◽

Wild Type ◽

Gliocladium Virens ◽

Rhizosphere Competence ◽

Filter Paper Cellulase ◽

Type Strains

Aqueous suspensions of conidia of Gliocladium virens strains Gl-3 and Gl-21 were exposed to both ultraviolet radiation and ethyl methanesulfonate. Two mutants of Gl-3 and three of Gl-21 were selected for tolerance to benomyl at 10 μg∙mL−1, as indicated by growth and conidial germination on benomyl-amended potato dextrose agar. The mutants differed considerably from their respective wild-type strains in appearance, growth habit, sporulation, carbon-source utilization, and enzyme activity profiles. Of 10 carbon sources tested, cellobiose, xylose, and xylan were the best for growth, galactose and glucose were intermediate, and arabinose, ribose, and rhamnose were poor sources of carbon. The wild-type strains and the mutants did not utilize cellulose as the sole carbon source for growth. Two benomyl-tolerant mutants of Gl-3 produced less cellulase (β-1,4-glucosidase, carboxymethylcellulase, filter-paper cellulase) than Gl-3. In contrast, mutants of Gl-21 produced more cellulase than the wild-type strain. Only Gl-3 provided control of blight on snapbean caused by Sclerotium rolfsii. Wild-type strain Gl-21 and all mutants from both strains were ineffective biocontrol agents. Key words: Gliocladium, benomyl tolerance, Sclerotium, rhizosphere competence.

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