scholarly journals COMPLEMENTATION OF AMOEBAL-PLASMODIAL TRANSITION MUTANTS IN PHYSARUM POLYCEPHALUM

Genetics ◽  
1979 ◽  
Vol 91 (3) ◽  
pp. 409-419
Author(s):  
Roger W Anderson
Keyword(s):  
Mating Type ◽  
Physarum Polycephalum ◽  
Current Work ◽  
Low Frequencies ◽  
Type Allele ◽  
Mating Compatibility ◽  
Complementation Groups

ABSTRACT Amoebae of the Myxomycete Physarum polycephalum differentiate to yield plasmodia in two ways: in crossing, haploid amoebae of appropriate genotypes fuse to form diploid plasmodia; in selfing, plasmodia form without amoebal fusion or increase in ploidy. Amoebae carrying the mating-type allele matAh (formerly mth) self efficiently, but occasionally give rise to mutants that self at very low frequencies. Such "amoebal-plasmodial transition" mutants were mixed in pairs to test their ability to complement one another in the formation of plasmodia by crossing. The pattern of crossing permitted 33 mutants to be assigned to four complementation groups (aptA-, npfA-, npfB- and npfC-). Similar tests had previously proved only partially successful, as crossing had occurred only rarely in mixtures of compatible strains. The efficiency of complementation was greatly increased in the current work by mixing strains that carried different alleles of a newly-discovered mating-compatibility locus, matB; this locus had no effect on the specificity of complementation. A possible interpretation of the complementation behavior of the mutants is suggested.

scholarly journals MUTATIONS INCREASING ASEXUAL PLASMODIUM FORMATION IN PHYSARUM POLYCEPHALUM

Genetics ◽  
1977 ◽  
Vol 87 (3) ◽  
pp. 401-420
Author(s):  
Paul N Adler ◽  
Charles E Holt
Keyword(s):  
Life Cycle ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
The Other ◽  
Type Allele ◽  
Cold Sensitive ◽  
The One

ABSTRACT Rare plasmodia formed in clones of heterothallic amoebae were analyzed in a search for mutations affecting plasmodium formation. The results show that the proportion of mutants varies with both temperature (18°, 26° or 30°) and mating-type allele (mt1, mt2, mt3, mt4). At one extreme, only one of 33 plasmoida formed by mt2 amoebae at 18° is mutant. At the other extreme, three of three plasmodia formed by mt1 amoebae at 30° are mutant. The mutant plasmodia fall into two groups, the GAD (greater asexual differentiation) mutants and the ALC (amoebaless life cycle) mutants. The spores of GAD mutants give rise to amoebae that differentiate into plasmodia asexually at much higher frequencies than normal heterothallic amoebae. Seven of eight gad mutations analyzed genetically are linked to mt and one (gad-12) is not. The gad-12 mutation is expressed in strains with different alleles of mt. The frequency of asexual plasmodium formation is heat sensitive in some (e.g., mt3 gad-11), heat-insensitive in two (mt2 gad-8 and mt2 gad-9) and cold-sensitive in one (mt1 gad-12) of twelve GAD mutants analyzed phenotypically. The spores of ALC mutants give rise to plasmodia directly, thereby circumventing the amoebal phase of the life cycle. Spores from five of the seven ALC mutants give rise to occasional amoebae, as well as plasmodia. The amoebae from one of the mutants carry a mutation (alc-1) that is unlinked to mt and is responsible for the ALC phenotype in this mutant. Like gad-12, alc-1 is expressed with different mt alleles. Preliminary observations with amoebae from the other four ALC mutants suggest that two are similar to the one containing alc-1; one gives rise to revertant amoebae, and one gives rise to amoebae carrying an alc mutation and a suppressor of the mutation.

scholarly journals A NEW MATING COMPATIBILITY LOCUS IN PHYSARUM POLYCEPHALUM

Genetics ◽  
1979 ◽  
Vol 91 (4) ◽  
pp. 683-693
Author(s):  
Philip J Youngman ◽  
Dominick J Pallotta ◽  
Betsy Hosler ◽  
Gary Struhl ◽  
Charles E Holt
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
Type Locus ◽  
Mating Type Locus ◽  
Mating Compatibility ◽  
Mating Efficiency ◽  
Mating Tests ◽  
Specificity System

ABSTRACT The rate and extent of plasmodium formation were studied in mating tests involving pairs of largely isogenic amoeba1 strains compatible for matingtype (mt) alleles. A systematic variability was observed: plasmodia formed either rapidly and extensively or slowly and inefficiently. Plasmodium formation was found to be 103- to 104-fold more extensive in "rapid" crosses than in "slow" crosses. A genetic analysis revealed that the variability reflects the influence of a multiallelic compatibility locus that determines mating efficiency. This compatibility locus (designated matB), together with the original mating type locus mt (in this work designated matA), constitute a tetrapolar mating specificity system in Physarum polycephalum.

scholarly journals Genetic regulation of differentiation inPhysarum polycephalum

1979 ◽  
Vol 34 (2) ◽  
pp. 131-142 ◽  
Author(s):  
N. K. Honey ◽  
R. T. M. Poulter ◽  
D. M. Teale
Keyword(s):  
Genetic Control ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
Genetic Regulation ◽  
Allele Specific ◽  
Complementation Groups

SUMMARYPlasmodial formation in the MyxomycetePhysarum polycephalumis controlled by a mating type (mt) locus. There are a number of different heterothallicmtalleles; and also a variant,mth, that allows plasmodial formation in pure clones. This paper reports an analysis of this differentiation system. The strainCL(mth) forms plasmodia in pure clones (i.e. it selfs).CLwas mutagenized with NMG and 21 mutants unable to differentiate into amoebae were isolated. The mutants, together withCLd, fell into two complementation groups, twelve indifAand ten indifB. Both complementation groups are closely linked or allelic to themtlocus.difArepresents a gene essential for plasmoclial formation, but it is suggested thatdifBrepresents a class of revertants to themt2heterothallic state. A model of the control of plasmodial formation is proposed in which themtlocus is suggested to code for the repressor of thedifAgene. Genetic control is explained in terms of the dilution of allele-specific repressors.

scholarly journals Selfing mutants from heterothallic strains of Physarum polycephalum

1981 ◽  
Vol 37 (2) ◽  
pp. 113-121 ◽  
Author(s):  
N. K. Honey ◽  
R. T. M. Poulter ◽  
P. J. Winter
Keyword(s):  
Temperature Effect ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
Single Locus ◽  
Mating Types ◽  
Specific Sensitivity

SUMMARYPlasmodial formation in the myxomycete Physarum polycephalum is controlled by a mating type (mt) locus, with heterothallic amoebae normally being unable to form plasmodia in pure clones. We report the isolation by mutagenesis of selfing mutants from heterothallic strains, and their analysis. Various amoebal strains of different mating types were mutagenized with a range of mutagens, and a number of selfing mutants (designated Het−) were isolated. A specific sensitivity of mt2 amoebae to mutagenesis by NMG was observed. This sensitivity segregated as a single locus closely linked or allelic to the mt2 locus. When the Het− clones were incubated at 30 °C, selfing was greatly inhibited. This property was used to determine the mt specificities of four Het− clones. The process of plasmodial induction in pure clones of CL was also studied using the 30 °C temperature effect.

scholarly journals On the universal trends in the noise reduction due to wavy leading edges in aerofoil–vortex interaction

2019 ◽  
Vol 871 ◽  
pp. 186-211 ◽  
Author(s):  
Jacob M. Turner ◽  
Jae Wook Kim
Keyword(s):  
Noise Reduction ◽  
High Frequency ◽  
Broadband Noise ◽  
Current Work ◽  
Source Distribution ◽  
Source Analysis ◽  
Frequency Noise ◽  
Frequency Spectra ◽  
Low Frequencies ◽  
Leading Edges

Existing studies suggest that wavy leading edges (WLEs) offer substantial reduction of broadband noise generated by an aerofoil undergoing upstream vortical disturbances. In this context, there are two universal trends in the frequency spectra of the noise reduction which have been observed and reported to date: (i) no significant reduction at low frequencies followed by (ii) a rapid growth of the noise reduction that persists in the medium-to-high frequency range. These trends are known to be insensitive to the aerofoil type and flow condition used. This paper aims to provide comprehensive understandings as to how these universal trends are formed and what the major drivers are. The current work is based on very-high-resolution numerical simulations of a semi-infinite flat-plate aerofoil impinged by a prescribed divergence-free vortex in an inviscid base flow at zero incidence angle, continued from recent work by the authors (Turner & Kim, J. Fluid Mech., vol. 811, 2017, pp. 582–611). One of the most significant findings in the current work is that the noise source distribution on the aerofoil surface becomes entirely two-dimensional (highly non-uniform in the spanwise direction as well as streamwise) at high frequencies when the WLE is involved. Also, the sources downstream of the LE make crucial contributions to creating the universal trends across all frequencies. These findings contradict the conventional LE-focused one-dimensional source analysis that has widely been accepted for all frequencies. The current study suggests that the universal trends in the noise-reduction spectra can be properly understood by taking the downstream source contributions into account, in terms of both magnitude and phase variations. After including the downstream sources, it is shown in this paper that the first universal trend is due to the conservation of total (surface integrated) source energy at low frequencies. The surface-integrated source magnitude that decreases faster with the WLE correlates very well with the noise-reduction spectrum at medium frequencies. In the meantime, the high-frequency noise reduction is driven almost entirely by destructive phase interference that increases rapidly and consistently with frequency, explaining the second universal trend.

scholarly journals Developmental mutants in a homothallic strain of Physarum polycephalum

1973 ◽  
Vol 21 (1) ◽  
pp. 79-86 ◽  
Author(s):  
A. E. Wheals
Keyword(s):  
Synergistic Effect ◽  
Ultraviolet Light ◽  
Mating Type ◽  
Physarum Polycephalum ◽  
High Efficiency ◽  
Type A ◽  
Wild Type ◽  
Developmental Transition ◽  
Developmental Mutants

SUMMARYA derivative line of the homothallic Colonia strain of Physarum polycephalum has been isolated which produces plasmodia with high efficiency within clones of amoebae. Using the synergistic effect of ultraviolet light and caffeine, mutants of this line have been isolated which fail to undergo the developmental transition between haploid amoebae and diploid plasmodia (apt mutants). They are isolated by selecting for amoebae which fail to produce plasmodia within clones. Complementation tests of four mutants have shown that they are mutants of four different loci and they are recessive to wild-type. A further analysis of one mutant reveals that the apt-1 locus is unlinked to three other known markers. Crosses of this mutant with heterothallic strains yield progeny which are homothallic indicating that the lesion is not a revertant from a homothallic to a heterothallic mating-type. The use of this system in isolating developmental mutants is discussed.

scholarly journals Mating type, mefenoxam sensitivity, and pathotype diversity in Phytophthora infestans isolates from tomato in Brazil

2010 ◽  
Vol 45 (7) ◽  
pp. 671-679 ◽  
Author(s):  
Bruno Eduardo Cardozo de Miranda ◽  
Nelson Dias Suassuna ◽  
Ailton Reis
Keyword(s):  
Phytophthora Infestans ◽  
Mating Type ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Average Frequency ◽  
Breeding Programs ◽  
Low Frequencies ◽  
Distrito Federal ◽  
Tomato Breeding ◽  
Major Resistance Genes

The objective of this work was to characterize 79 Phytophthora infestans isolates collected in tomato (Solanum lycopersicum) fields, as to mating type, mefenoxam sensitivity, and pathotype composition. The isolates were sampled in 2006 and 2007 in seven Brazilian states as well as in the Distrito Federal. They were characterised as to mating type (n=79), sensitivity to fungicide mefenoxam (n=79), and virulence to three major resistance genes Ph-1, Ph-2, and Ph-3/Ph-4 (n=62). All isolates were of the mating type A1. Resistant isolates were detected in all sampled states, and its average frequency was superior to 50%. No difference was detected in pathotype diversity, neither between subpopulations collected in 2006 and 2007 nor between isolates grouped as resistant or intermediately sensitive to mefenoxam. All major resistance genes were overcome at different frequencies: Ph-1, 88.7%; Ph-2, 64.5%; and Ph-3/Ph-4, 25.8%. Isolates with virulence genes able to overcome all major resistance genes were detected at low frequencies. Tomato breeding programs in Brazil must avoid the development of cultivars with resistance based exclusively on major genes.

scholarly journals Isolation and genetic analysis of Saccharomyces cerevisiae mutants supersensitive to G1 arrest by a factor and alpha factor pheromones.

1982 ◽  
Vol 2 (1) ◽  
pp. 11-20 ◽  
Author(s):  
R K Chan ◽  
C A Otte
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
Solid Medium ◽  
G1 Arrest ◽  
Alpha Cells ◽  
Opposite Mating Type ◽  
Alpha Factor ◽  
Complementation Groups ◽  
Chromosome Iii ◽  
The Right

Eight independently isolated mutants which are supersensitive (Sst-) to the G1 arrest induced by the tridecapeptide pheromone alpha factor were identified by screening mutagenized Saccharomyces cerevisiae MATa cells on solid medium for increased growth inhibition by alpha factor. These mutants carried lesions in two complementation groups, sst1 and sst2. Mutations at the sst1 locus were mating type specific: MATa sst1 cells were supersensitive to alpha factor, but MAT alpha sst1 cells were not supersensitive to a factor. In contrast, mutations at the sst2 locus conferred supersensitivity to the pheromones of the opposite mating type on both MATa and MAT alpha cells. Even in the absence of added alpha pheromone, about 10% of the cells in exponentially growing cultures of MATa strains carrying any of three different alleles of sst2 (including the ochre mutation sst2-4) had the aberrant morphology ("shmoo" shape) that normally develops only after MATa cells are exposed to alpha factor. This "self-shmooing" phenotype was genetically linked to the sst2 mutations, although the leakiest allele isolated (sst2-3) did not display this characteristic. Normal MATa/MAT alpha diploids do not respond to pheromones; diploids homozygous for an sst2 mutation (MATa/MAT alpha sst2-1/sst2-1) were still insensitive to alpha factor. The sst1 gene was mapped to within 6.9 centimorgans of his6 on chromosome IX. The sst2 gene was unlinked to sst1, was not centromere linked, and was shown to be neither linked to nor centromere distal to MAT on the right arm of chromosome III.

scholarly journals Genetic structure and evolutionary diversity of mating-type (MAT) loci in Hypsizygus marmoreus

IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gang Wang ◽  
Yuanyuan Wang ◽  
Lianfu Chen ◽  
Hongbo Wang ◽  
Lin Guo ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Mating Type ◽  
Phylogenetic Analyses ◽  
Schizophyllum Commune ◽  
Edible Mushroom ◽  
Hypsizygus Marmoreus ◽  
Pheromone Receptor ◽  
Recombination Hotspots ◽  
Mating Compatibility ◽  
Genetic Structure And Diversity

AbstractThe mating compatibility in fungi is generally governed by genes located within a single or two unlinked mating type (MAT) loci. Hypsizygus marmoreus is an edible mushroom in the order Agaricales with a tetrapolar system, which contains two unlinked MAT loci-homeodomain (HD) transcription factor genes and pheromone/pheromone receptor genes (P/R). In this study, we analyzed the genetic structure and diversity of MAT loci in tetrapolar system of H. marmoreus through sequencing of 54 heterokaryon and 8 homokaryon strains. Although within the HD loci, the gene order was conserved, the gene contents were variable, and the HD loci haplotypes were further classified into four types. By analyzing the structure, phylogeny, and the HD transmissibility based on the progeny of these four HD mating-type loci types, we found that they were heritable and tightly linked at the HD loci. The P/R loci genes were found to comprise three pheromone receptors, three pheromones, and two pheromone receptor-like genes. Intra- and inter-specific phylogenetic analyses of pheromone receptors revealed that the STE3 genes were divided into three groups, and we thus theorize that they diverged before speciation. Comparative analysis of the MAT regions among 73 Basidiomycete species indicated that the diversity of HD and P/R loci in Agaricales and Boletales may contribute to mating compatibility. The number of HD genes were not correlated with the tetrapolar or bipolar systems. In H. marmoreus, the expression levels of these genes at HD and P/R loci of compatible strains were found higher than in those of homonuclear/homokaryotic strains, indicating that these mating genes acted as switches for mating processes. Further collinear analysis of HD loci in interspecific species found that HD loci contains conserved recombination hotspots showing major rearrangements in Coprinopsis cinerea and Schizophyllum commune, suggesting different mechanisms for evolution of physically linked MAT loci in these groups. It seems likely that gene rearrangements are common in Agaricales fungi around HD loci. Together, our study provides insights into the genomic basis of mating compatibility in H. marmoreus.

scholarly journals TWO MULTIALLELIC MATING COMPATIBILITY LOCI SEPARATELY REGULATE ZYGOTE FORMATION AND ZYGOTE DIFFERENTIATION IN THE MYXOMYCETE PHYSARUM POLYCEPHALUM

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 513-530
Author(s):  
Philip J Youngman ◽  
Roger W Anderson ◽  
Charles E Holt
Keyword(s):  
Physarum Polycephalum ◽  
Zygote Formation ◽  
Present Evidence ◽  
Mating Compatibility ◽  
Extensive Growth ◽  
Diploid Cells

ABSTRACT The mating of Physarum polycephalum amoebae, the ultimate consequence of which is a "plasmodium," was recently shown to be governed by two compatibility loci, matA (or mt) and matB (DEE1 978; YOUNGMAeNt aZ. 1979), We present evidence that matA and matB separately regulate two discrete stages of mating: in the first stage, amoebae (which are normally haploid) fuse in pairs, with a specificity determined by matB genotype, to form diploid zygotes; subsequent differentiation of the zygotes into plasmodia is regulated by matA and is unaffected by matB. Mixtures of amoebae carrying unlike matA and matB alleles formed diploids to the extent of 10 to 15% of the cells present, and the diploids differentiated into plasmodia. When only the matB alleles differed, diploid cells still formed to a comparable (5 to 101%) extent, but rather than differentiating, these diploids remained amoebae. When strains carried the same alleles of matB, formation of diploid cells was greatly reduced: in like matB, like-matd mixtures, none of 320 cells examined was diploid; in like maiB, unlike mat-A mixtures, differentiating diploids could be detected, but at only IO-3 to 10-2 the frequency of unlike-matB, unlike-matA mixtures. The nondifferentiating diploid amoebae recovered from unlike-matB, like-matA mixtures were genetically stable through extensive growth, even though they grew more slowly than haploids (10-hr us. 8-hr doubling period), and could be crossed with both haploids and diploids. The results of such higher ploidy and mixed ploidy crosses indicate that karyogamy does not invariably accompany zygote formation and differentiation.

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