scholarly journals Genomic and Population Analyses of the Mating Type Loci in Coccidioides Species Reveal Evidence for Sexual Reproduction and Gene Acquisition

2007 ◽  
Vol 6 (7) ◽  
pp. 1189-1199 ◽  
Author(s):  
M. Alejandra Mandel ◽  
Bridget M. Barker ◽  
Scott Kroken ◽  
Steven D. Rounsley ◽  
Marc J. Orbach
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Mating Types ◽  
Coccidioides Immitis ◽  
Genome Sequences ◽  
Valley Fever ◽  
Population Analyses ◽  
Gene Acquisition ◽  
Close Proximity

ABSTRACT Coccidioides species, the fungi responsible for the valley fever disease, are known to reproduce asexually through the production of arthroconidia that are the infectious propagules. The possible role of sexual reproduction in the survival and dispersal of these pathogens is unexplored. To determine the potential for mating of Coccidioides, we analyzed genome sequences and identified mating type loci characteristic of heterothallic ascomycetes. Coccidioides strains contain either a MAT1-1 or a MAT1-2 idiomorph, which is 8.1 or 9 kb in length, respectively, the longest reported for any ascomycete species. These idiomorphs contain four or five genes, respectively, more than are present in the MAT loci of most ascomycetes. Along with their cDNA structures, we determined that all genes in the MAT loci are transcribed. Two genes frequently found in common sequences flanking MAT idiomorphs, APN2 and COX13, are within the MAT loci in Coccidioides, but the MAT1-1 and MAT1-2 copies have diverged dramatically from each other. Data indicate that the acquisition of these genes in the MAT loci occurred prior to the separation of Coccidioides from Uncinocarpus reesii. An analysis of 436 Coccidioides isolates from patients and the environment indicates that in both Coccidioides immitis and C. posadasii, there is a 1:1 distribution of MAT loci, as would be expected for sexually reproducing species. In addition, an analysis of isolates obtained from 11 soil samples demonstrated that at three sampling sites, strains of both mating types were present, indicating that compatible strains were in close proximity in the environment.

scholarly journals Deletion of the Schizophyllum commune Aα Locus: The Roles of Aα Y and Z Mating-Type Genes

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1437-1444
Author(s):  
C Ian Robertson ◽  
Kirk A Bartholomew ◽  
Charles P Novotny ◽  
Robert C Ullrich
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Mating Types ◽  
Developmental Pathway ◽  
Mating Type Gene ◽  
Mating Type Genes ◽  
Regulatory Loci ◽  
Type Gene

The Aα locus is one of four master regulatory loci that determine mating type and regulate sexual development in Schizophyllum commune. We have made a plasmid containing a URA1 gene disruption of the Aα Y1 gene. Y1 is the sole Aα gene in Aα1 strains. We used the plasmid construction to produce an Aα null (i.e., AαΔ) strain by replacing the genomic Y1 gene with URA1 in an Aα1 strain. To characterize the role of the Aα genes in the regulation of sexual development, we transformed various Aα Y and Z alleles into AαΔ strains and examined the acquired mating types and mating abilities of the transformants. These experiments demonstrate that the Aα Y gene is not essential for fungal viability and growth, that a solitary Z Aα mating-type gene does not itself activate development, that Aβ proteins are sufficient to activate the A developmental pathway in the absence of Aα proteins and confirm that Y and Z genes are the sole determinants of Aα mating type. The data from these experiments support and refine our model of the regulation of A-pathway events by Y and Z proteins.

Identification of biosynthetic intermediates for the mating hormone α2 of the plant pathogen Phytophthora

2021 ◽  
Author(s):  
Suguru Ariyoshi ◽  
Yusuke Imazu ◽  
Ryuji Ohguri ◽  
Ryo Katsuta ◽  
Arata Yajima ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Sexual Reproduction ◽  
Mating Type ◽  
Plant Pathogen ◽  
Type Strain ◽  
Mating Types ◽  
Synthetic Intermediates ◽  
The Cross

Abstract The heterothallic group of the plant pathogen Phytophthora can sexually reproduce between the cross-compatible mating types A1 and A2. The mating hormone α2, produced by A2 mating type and utilized to promote the sexual reproduction of the partner A1 type, is known to be biosynthesized from phytol. In this study, we identified two biosynthetic intermediates, 11- and 16-hydroxyphytols (1 and 2), for α2 by administering the synthetic intermediates to an A2 type strain to produce α2 and by administering phytol to A2 strains to detect the intermediates in the mycelia. The results suggest that α2 is biosynthesized by possibly two cytochrome P450 oxygenases via two hydroxyphytol intermediates (1 and 2) in A2 hyphae and secreted outside.

scholarly journals Invasion and extinction dynamics of mating types under facultative sexual reproduction

2019 ◽  
Author(s):  
Peter Czuppon ◽  
George W. A. Constable
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Average Rate ◽  
Natural Populations ◽  
Null Model ◽  
Mating Types ◽  
Stationary Probability Distribution ◽  
Time To Extinction ◽  
Establishment Probability ◽  
Mean Time

AbstractIn sexually reproducing isogamous species, syngamy between gametes is generally not indiscriminate, but rather restricted to occurring between complementary self-incompatible mating types. A longstanding question regards the evolutionary pressures that control the number of mating types observed in natural populations, which ranges from two to many thousands. Here, we describe a population genetic null model of this reproductive system and derive expressions for the stationary probability distribution of the number of mating types, the establishment probability of a newly arising mating type and the mean time to extinction of a resident type. Our results yield that the average rate of sexual reproduction in a population correlates positively with the expected number of mating types observed. We further show that the low number of mating types predicted in the rare-sex regime is primarily driven by low invasion probabilities of new mating type alleles, with established resident alleles being very stable over long evolutionary periods. Moreover, our model naturally exhibits varying selection strength dependent on the number of present mating types. This results in higher extinction and lower invasion rates for an increasing number of residents.

scholarly journals GENETIC ANALYSIS OF MATING TYPE DIFFERENTIATION IN PARAMECIUM TETRAURELIA. II. ROLE OF THE MICRONUCLEI IN MATING-TYPE DETERMINATION

Genetics ◽  
1980 ◽  
Vol 94 (4) ◽  
pp. 951-959
Author(s):  
Y Brygoo ◽  
T M Sonneborn ◽  
A M Keller ◽  
R V Dippell ◽  
M V Schneller
Keyword(s):  
Genetic Analysis ◽  
Mating Type ◽  
Cytoplasmic Inheritance ◽  
Mating Types ◽  
Paramecium Tetraurelia ◽  
Macronuclear Development ◽  
Cytoplasmic Factors ◽  
Determining Factors

ABSTRACT The two complementary mating types, 0 and E, of Paramecium tetrauretia are normally inherited cytoplasmically. This property has generally been interpreted to indicate the presence of cytoplasmic factors that determine macronuclear differentiation towards 0 or E . In these macronuclear-cytoplasmic interactions, the micronuclei were held to be unbiased and the determination to be established in the course of macronuclear development. In order to ascertain whether the micronuclei were actually neutral, amicronucleate clones were needed and a method to produce them was developed. In crosses between amicronucleate clones and normal micronucleate clones, we have observed regular deviations from cytoplasmic inheritance: the commonest deviation is that most 0 amicronucleate cells become E when they receive a micronucleus from an E partner. The data can be interpreted by assuming that the micronuclei are predetermined and that the apparent "cytoplasmic" inheritance of the two mating types is due, in E cells, to E-determining factors present in the cytoplasm and in the nucleus; and, in 0 cells, to 0-determining factors present only or mainly in the nucleus.

scholarly journals Genetic Structure of the Phytophthora infestans Population in Morocco

Plant Disease ◽  
2000 ◽  
Vol 84 (2) ◽  
pp. 173-176 ◽  
Author(s):  
M. Sedegui ◽  
R. B. Carroll ◽  
A. L. Morehart ◽  
T. A. Evans ◽  
S. H. Kim ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Late Blight ◽  
Sexual Reproduction ◽  
Phytophthora Infestans ◽  
Mating Type ◽  
Potato Seed ◽  
Mating Types ◽  
Potato Field ◽  
New Genotype

ABSRACT In 1996 to 1998, a late-blight survey was conducted in potato- and tomato-growing regions of Morocco. A total of 149 isolates of Phytophthora infestans were collected and analyzed for the glucose-6-phosphate isomerase (Gpi) and peptidase (Pep) alleles, mating types, and metalaxyl sensitivities. Four genotypes were identified: MO-1 (mating type A1, Gpi 100/100, Pep 92/100), MO-2 (mating type A1, Gpi 86/100, Pep 92/100), MO-3 (mating type A2 Gpi 100/100, Pep 100/100), and MO-4 (mating type A1, Gpi 100/100, Pep 100/100). The potato isolates were MO-1 (1996 & 97), MO-3 (1998), and MO-4 (1998). The frequencies of A1 (MO-4) and A2 (MO-3) mating types in potato fields in 1998 were 26 and 74%, respectively. Potato isolates were pathogenic to both potatoes and tomatoes. The isolates collected from tomatoes in 1997 and 1998 were MO-2. Potato and tomato isolates were insensitive and sensitive to metalaxyl, respectively. The change of genotype population in 1998 was probably caused by migration of a new genotype from Europe associated with importation of potato seed. The detection of A1 and A2 mating types in the same potato field indicates the potential for sexual reproduction of P. infestans in Morocco.

scholarly journals Mating-Type Gene Structure and Spatial Distribution of Didymella tanaceti in Pyrethrum Fields

2016 ◽  
Vol 106 (12) ◽  
pp. 1521-1529 ◽  
Author(s):  
Tamieka L. Pearce ◽  
Jason B. Scott ◽  
Frank S. Hay ◽  
Sarah J. Pethybridge
Keyword(s):  
Spatial Distribution ◽  
Mating Type ◽  
Tan Spot ◽  
Mating Types ◽  
Tanacetum Cinerariifolium ◽  
Polymerase Chain ◽  
Type Gene ◽  
Mat Genes

Tan spot of pyrethrum (Tanacetum cinerariifolium) is caused by the ascomycete Didymella tanaceti. To assess the evolutionary role of ascospores in the assumed asexual species, the structure and arrangement of mating-type (MAT) genes were examined. A single MAT1-1 or MAT1-2 idiomorph was identified in all isolates examined, indicating that the species is heterothallic. The idiomorphs were flanked upstream and downstream by regions encoding pyridoxamine phosphate oxidase-like and DNA lyase-like proteins, respectively. A multiplex MAT-specific polymerase chain reaction assay was developed and used to genotype 325 isolates collected within two transects in each of four fields in Tasmania, Australia. The ratio of isolates of each mating-type in each transect was consistent with a 1:1 ratio. The spatial distribution of the isolates of the two mating-types within each transect was random for all except one transect for MAT1-1 isolates, indicating that clonal patterns of each mating-type were absent. However, evidence of a reduced selection pressure on MAT1-1 isolates was observed, with a second haplotype of the MAT1-1-1 gene identified in 4.4% of MAT1-1 isolates. In vitro crosses between isolates with opposite mating-types failed to produce ascospores. Although the sexual morph could not be induced, the occurrence of both mating-types in equal frequencies suggested that a cryptic sexual mode of reproduction may occur within field populations.

scholarly journals Mating-Type Distribution and Genetic Diversity of Cercospora sojina Populations on Soybean from Arkansas: Evidence for Potential Sexual Reproduction

2013 ◽  
Vol 103 (10) ◽  
pp. 1045-1051 ◽  
Author(s):  
Hun Kim ◽  
Annakay D. Newell ◽  
Robyn G. Cota-Sieckmeyer ◽  
John C. Rupe ◽  
Ahmad M. Fakhoury ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Spatial Scales ◽  
Genotypic Diversity ◽  
The United States ◽  
Economic Losses ◽  
Mating Types ◽  
Cercospora Sojina ◽  
Single Leaf ◽  
Corrected Data

Cercospora sojina causes frogeye leaf spot of soybean, which can cause serious economic losses in the United States. In this study, 132 C. sojina isolates were collected from six fields (from two counties, Cross and Crawford) in Arkansas. To determine mating type, a multiplex polymerase chain reaction assay was developed with primers specific for C. sojina. Of the 132 isolates, 68 isolates had the MAT1-1-1 idiomorph and 64 isolates had the MAT1-2 idiomorph; no isolates possessed both idiomorphs. Both mating types were present in a variety of spatial scales, including separate lesions on individual leaves. Clone-corrected data from eight microsatellites indicated that mating-type loci were present in approximately equal proportions in all populations analyzed, which suggests that Arkansas populations of C. sojina are undergoing cryptic sexual reproduction. All six populations evaluated had high genotypic diversity of 26 to 79%. In addition, among strains isolated from a single leaf, multiple and distinct haplotypes were associated with both mating types, supporting the hypothesis that sexual reproduction occurs within the populations. Most populations showed significant gametic disequilibrium but levels of disequilibrium were relatively low, particularly in populations from Crawford County. A low differentiation index (GST) was observed for all simple-sequence repeat markers across all populations. Furthermore, the value of G statistics between populations suggests that significant genetic exchange exists among the populations. Taken together, these results demonstrate that C. sojina populations from Arkansas are genetically diverse and most likely undergoing sexual reproduction.

scholarly journals Fitness differences suppress the number of mating types in evolving isogamous species

2020 ◽  
Vol 7 (2) ◽  
pp. 192126 ◽  
Author(s):  
Yvonne Krumbeck ◽  
George W. A. Constable ◽  
Tim Rogers
Keyword(s):  
Sexual Reproduction ◽  
Mathematical Analysis ◽  
Evolutionary Biology ◽  
Mortality Rates ◽  
Equal Size ◽  
Mating Types ◽  
Evolutionary Models ◽  
Open Question ◽  
Sex Cells

Sexual reproduction is not always synonymous with the existence of two morphologically different sexes; isogamous species produce sex cells of equal size, typically falling into multiple distinct self-incompatible classes, termed mating types. A long-standing open question in evolutionary biology is: what governs the number of these mating types across species? Simple theoretical arguments imply an advantage to rare types, suggesting the number of types should grow consistently; however, empirical observations are very different. While some isogamous species exhibit thousands of mating types, such species are exceedingly rare, and most have fewer than 10. In this paper, we present a mathematical analysis to quantify the role of fitness variation—characterized by different mortality rates—in determining the number of mating types emerging in simple evolutionary models. We predict that the number of mating types decreases as the variance of mortality increases.

Isolation and characterization of the mating-type locus of the barley pathogen Pyrenophora teres and frequencies of mating-type idiomorphs within and among fungal populations collected from barley landraces

Genome ◽  
2005 ◽  
Vol 48 (5) ◽  
pp. 855-869 ◽  
Author(s):  
Domenico Rau ◽  
Frank J Maier ◽  
Roberto Papa ◽  
Anthony H.D Brown ◽  
Virgilio Balmas ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Mating Type ◽  
Clonal Selection ◽  
Leptosphaeria Maculans ◽  
Aflp Analysis ◽  
Pyrenophora Teres ◽  
Mating Types ◽  
Type Locus ◽  
Barley Landrace ◽  
Isolation And Characterization

Pyrenophora teres f. sp. teres mating-type genes (MAT-1: 1190 bp; MAT-2: 1055 bp) have been identified. Their predicted proteins, measuring 379 and 333 amino acids, respectively, are similar to those of other Pleosporales, such as Pleospora sp., Cochliobolus sp., Alternaria alternata, Leptosphaeria maculans, and Phaeosphaeria nodorum. The structure of the MAT locus is discussed in comparison with those of other fungi. A mating-type PCR assay has also been developed; with this assay we have analyzed 150 isolates that were collected from 6 Sardinian barley landrace populations. Of these, 68 were P. teres f. sp. teres (net form; NF) and 82 were P. teres f. sp. maculata (spot form; SF). Within each mating type, the NF and SF amplification products were of the same length and were highly similar in sequence. The 2 mating types were present in both the NF and the SF populations at the field level, indicating that they have all maintained the potential for sexual reproduction. Despite the 2 forms being sympatric in 5 fields, no intermediate isolates were detected with amplified fragment length polymorphism (AFLP) analysis. These results suggest that the 2 forms are genetically isolated under the field conditions. In all of the samples of P. teres, the ratio of the 2 mating types was consistently in accord with the 1:1 null hypothesis. This ratio is expected when segregation distortion and clonal selection among mating types are absent or asexual reproduction is rare. Overall, sexual reproduction appears to be the major process that equalizes the frequencies of the 2 mating types within populations.Key words: Pyrenophora teres, mating-types, AFLPs, sexual reproduction, selection, barley.

scholarly journals Evolution of asymmetric gamete signaling and suppressed recombination at the mating type locus

2019 ◽  
Author(s):  
Zena Hadjivasiliou ◽  
Andrew Pomiankowski
Keyword(s):  
Mating Type ◽  
Mating Types ◽  
Linkage Groups ◽  
Type Locus ◽  
The Road ◽  
Receptor Dynamics ◽  
Tight Linkage ◽  
Suppressed Recombination ◽  
Selection For

AbstractThe two partners required for sexual reproduction are rarely the same. This pattern extends to species which lack sexual dimorphism yet possess self-incompatible gametes determined at mating-type regions of suppressed recombination, likely precursors of sex chromosomes. Here we investigate the role of cellular signaling in the evolution of mating-types. We develop a model of ligand-receptor dynamics within cells, and identify factors that determine the capacity of cells to send and receive signals. The model specifies conditions favoring the evolution of gametes producing ligand and receptor asymmetrically and shows how these are affected by recombination. When the recombination rate can evolve, the conditions favoring asymmetric signaling also favor tight linkage of ligand and receptor loci in distinct linkage groups. These results suggest that selection for asymmetric signaling between gametes was the first step in the evolution of non-recombinant mating-type loci, paving the road for the evolution of anisogamy and sexes.

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