Mating types and sexual development in filamentous ascomycetes

1997 ◽  
Vol 61 (4) ◽  
pp. 411-428 ◽  
Author(s):  
E Coppin ◽  
R Debuchy ◽  
S Arnaise ◽  
M Picard
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Single Species ◽  
Podospora Anserina ◽  
Type Model ◽  
Mating Types ◽  
Dna Binding Domains ◽  
Binding Domains ◽  
Hormonal Signal ◽  
Mat Genes

The progress made in the molecular characterization of the mating types in several filamentous ascomycetes has allowed us to better understand their role in sexual development and has brought to light interesting biological problems. The mating types of Neurospora crassa, Podospora anserina, and Cochliobolus heterostrophus consist of unrelated and unique sequences containing one or several genes with multiple functions, related to sexuality or not, such as vegetative incompatibility in N. crassa. The presence of putative DNA binding domains in the proteins encoded by the mating-type (mat) genes suggests that they may be transcriptional factors. The mat genes play a role in cell-cell recognition at fertilization, probably by activating the genes responsible for the hormonal signal whose occurrence was previously demonstrated by physiological experiments. They also control recognition between nuclei at a later stage, when reproductive nuclei of each mating type which have divided in the common cytoplasm pair within the ascogenous hyphae. How self is distinguished from nonself at the nuclear level is not known. The finding that homothallic species, able to mate in the absence of a partner, contain both mating types in the same haploid genome has raised more issues than it has resolved. The instability of the mating type, in particular in Sclerotinia trifolorium and Botrytinia fuckeliana, is also unexplained. This diversity of mating systems, still more apparent if the yeasts and the basidiomycetes are taken into account, clearly shows that no single species can serve as a universal mating-type model.

scholarly journals Molecular Genetics of Mating Recognition in Basidiomycete Fungi

1998 ◽  
Vol 62 (1) ◽  
pp. 55-70 ◽  
Author(s):  
Lorna A. Casselton ◽  
Natalie S. Olesnicky
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Schizophyllum Commune ◽  
Single Species ◽  
Podospora Anserina ◽  
Mating Types ◽  
Active Transcription ◽  
Mating Type Genes ◽  
Type Gene ◽  
Basidiomycete Fungi

SUMMARY The recognition of compatible mating partners in the basidiomycete fungi requires the coordinated activities of two gene complexes defined as the mating-type genes. One complex encodes members of the homeobox family of transcription factors, which heterodimerize on mating to generate an active transcription regulator. The other complex encodes peptide pheromones and 7-transmembrane receptors that permit intercellular signalling. Remarkably, a single species may have many thousands of cross-compatible mating types because the mating-type genes are multiallelic. Different alleles of both sets of genes are necessary for mating compatibility, and they trigger the initial stages of sexual development—the formation of a specialized filamentous mycelium termed the dikaryon, in which the haploid nuclei remain closely associated in each cell but do not fuse. Three species have been taken as models to describe the molecular structure and organization of the mating-type loci and the genes sequestered within them: the pathogenic smut fungus Ustilago maydis and the mushrooms Coprinus cinereus and Schizophyllum commune. Topics addressed in this review are the roles of the mating-type gene products in regulating sexual development, the molecular basis for multiple mating types, and the molecular interactions that permit different allelic products of the mating type genes to be discriminated. Attention is drawn to the remarkable conservation in the mechanisms that regulate sexual development in basidiomycetes and unicellular ascomycete yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, a theme which is developed in the general conclusion to include the filamentous ascomycetes Neurospora crassa and Podospora anserina.

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.

scholarly journals Two Copies of mthmg1, Encoding a Novel Mitochondrial HMG-Like Protein, Delay Accumulation of Mitochondrial DNA Deletions in Podospora anserina

2002 ◽  
Vol 1 (4) ◽  
pp. 503-513 ◽  
Author(s):  
Michelle Dequard-Chablat ◽  
Cynthia Alland
Keyword(s):  
Mitochondrial Dna ◽  
Dna Binding ◽  
Mitochondrial Genome ◽  
Life Span ◽  
Cellular Localization ◽  
Premature Death ◽  
Podospora Anserina ◽  
Protein Fusion ◽  
Dna Binding Domains ◽  
Binding Domains

ABSTRACT In the filamentous fungus Podospora anserina, two degenerative processes which result in growth arrest are associated with mitochondrial genome (mitochondrial DNA [mtDNA]) instability. Senescence is correlated with mtDNA rearrangements and amplification of specific regions (senDNAs). Premature death syndrome is characterized by the accumulation of specific mtDNA deletions. This accumulation is due to indirect effects of the AS1-4 mutation, which alters a cytosolic ribosomal protein gene. The mthmg1 gene has been identified as a double-copy suppressor of premature death. It greatly delays premature death and the accumulation of deletions when it is present in two copies in an AS1-4 context. The duplication of mthmg1 has no significant effect on the wild-type life span or on senDNA patterns. In an AS1 + context, deletion of the mthmg1 gene alters germination, growth, and fertility and reduces the life span. The Δmthmg1 senescent strains display a particular senDNA pattern. This deletion is lethal in an AS1-4 context. According to its physical properties (very basic protein with putative mitochondrial targeting sequence and HMG-type DNA-binding domains) and the cellular localization of an mtHMG1-green fluorescent protein fusion, mtHMG1 appears to be a mitochondrial protein possibly associated with mtDNA. It is noteworthy that it is the first example of a protein combining the two DNA-binding domains, AT-hook motif and HMG-1 boxes. It may be involved in the stability and/or transmission of the mitochondrial genome. To date, no structural homologues have been found in other organisms. However, mtHMG1 displays functional similarities with the Saccharomyces cerevisiae mitochondrial HMG-box protein Abf2.

scholarly journals Cloning the mating types of the heterothallic fungus Podospora anserina: developmental features of haploid transformants carrying both mating types.

Genetics ◽  
1991 ◽  
Vol 128 (3) ◽  
pp. 539-547 ◽  
Author(s):  
M Picard ◽  
R Debuchy ◽  
E Coppin
Keyword(s):  
Mating Type ◽  
Gene Replacement ◽  
Podospora Anserina ◽  
The Other ◽  
Mating Types ◽  
Body Development ◽  
Fruiting Body Development ◽  
Mat Locus ◽  
Functional Analyses ◽  
Developmental Features

Abstract DNAs that encode the mating-type functions (mat+ and mat-) of the filamentous fungus Podospora anserina were cloned with the use of the mating-type A probe from Neurospora crassa. Cloning the full mat information was ascertained through gene replacement experiments. Molecular and functional analyses of haploid transformants carrying both mating types lead to several striking conclusions. Mat+ mat- strains are dual maters. However, the resident mat information is dominant to the mat information added by transformation with respect to fruiting body development and ascus production. Moreover, when dual mating mat+ mat- strains are crossed to mat+ or mat- testers, there is strong selection, after fertilization, that leads to the loss from the mat+ mat- nucleus of the mat information that matches that of the tester. Finally, the mat locus contains at least two domains, one sufficient for fertilization, the other necessary for sporulation.

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 MAT Loci Play Crucial Roles in Sexual Development but Are Dispensable for Asexual Reproduction and Pathogenicity in Rice Blast Fungus Magnaporthe oryzae

2021 ◽  
Vol 7 (10) ◽  
pp. 858
Author(s):  
Jiao-yu Wang ◽  
Shi-zhen Wang ◽  
Zhen Zhang ◽  
Zhong-na Hao ◽  
Xiao-xiao Shi ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sexual Reproduction ◽  
Asexual Reproduction ◽  
Magnaporthe Oryzae ◽  
Sexual Development ◽  
Fungal Pathogen ◽  
Rice Blast ◽  
Molecular Mechanisms ◽  
Mating Types ◽  
Mat Genes

Magnaporthe oryzae, a fungal pathogen that causes rice blast, which is the most destructive disease of rice worldwide, has the potential to perform both asexual and sexual reproduction. MAT loci, consisting of MAT genes, were deemed to determine the mating types of M. oryzae strains. However, investigation was rarely performed on the development and molecular mechanisms of the sexual reproduction of the fungus. In the present work, we analyzed the roles of two MAT loci and five individual MAT genes in the sex determination, sexual development and pathogenicity of M. oryzae. Both of the MAT1-1 and MAT1-2 loci are required for sex determination and the development of sexual structures. MAT1-1-1, MAT1-1-3 and MAT1-2-1 genes are crucial for the formation of perithecium. MAT1-1-2 impacts the generation of asci and ascospores, while MAT1-2-2 is dispensable for sexual development. A GFP fusion experiment indicated that the protein of MAT1-1-3 is distributed in the nucleus. However, all of the MAT loci or MAT genes are dispensable for vegetative growth, asexual reproduction, pathogenicity and pathogenicity-related developments of the fungus, suggesting that sexual reproduction is regulated relatively independently in the development of the fungus. The data and methods of this work may be helpful to further understand the life cycle and the variation of the fungus.

Species-specific and mating type-specific DNA regions adjacent to mating type idiomorphs in the genus Neurospora.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 119-136 ◽  
Author(s):  
T A Randall ◽  
R L Metzenberg
Keyword(s):  
Mating Type ◽  
Sexual Development ◽  
Evolutionary Relationship ◽  
Mating Types ◽  
Variable Regions ◽  
Sequence Identity ◽  
Hybridization Data ◽  
Evolutionarily Conserved ◽  
Species Specific ◽  
Specific Sequences

Abstract Mating type idiomorphs control mating and subsequent sexual development in Neurospora crassa and were previously shown to be well conserved in other Neurospora species. The centromere-proximal flanks of the A and a idiomorphs, but not the distal flanks from representative heterothallic, pseudohomothallic, and homothallic Neurospora species contain apparent species-specific and/or mating type-specific sequences adjacent to the well-conserved idiomorphs. The variable flank is bordered by regions that are highly homologous in all species. The sequence of approximately 1 kb immediately flanking the conserved idiomorphs of each species was determined. Sequence identity between species ranged from 20% (essentially unrelated) to > 90%. By contrast, the mt-A1 gene shows 88-98% identity. Sequence and hybridization data also show that the centromere-proximal flanks are very different between the two mating types for N. intermedia, N. discreta, and N. tetrasperma, but not for N. sitophila and N. crassa. The data suggest a close evolutionary relationship between several of the species; this is suppported by phylogenetic analysis of their respective mt-A1 genes. The origin of the variable regions adjacent to the evolutionarily conserved mating type idiomorphs is unknown.

scholarly journals A NEUROSPORA MUTATION THAT ARRESTS PERITHECIAL DEVELOPMENT AS EITHER MALE OR FEMALE PARENT

Genetics ◽  
1979 ◽  
Vol 92 (4) ◽  
pp. 1107-1120
Author(s):  
Thomas E Johnson
Keyword(s):  
Gene Product ◽  
Mating Type ◽  
Sexual Development ◽  
Female Parent ◽  
Male Parent ◽  
Mixed Mating ◽  
Single Mutation ◽  
Mating Types ◽  
Female Component ◽  
Ascospore Formation

ABSTRACT A mutant of Neurospora crassa fails to produce perithecia when crossed as either the male (fertilizing) parent or the female (protoperithecial) parent. This mutant is unique in that it appears to be due to a single mutation that blocks sexual development when crossed as either parent. As either a male or female parent, the mutant, fmf-1, produces perithecia blocked at a diameter of 120 microns and containing no meiotic figures; normal perithecia are over 4.00 microns in diameter. The mutant maps to linkage group IL near arg-1. Forced heterokaryons have been made between fmf-1 and fmf-1  + nuclei. These heterokaryons are fertile when crossed, and fmf-1 can participate as either the male or female component; the mutation is thus heterokaryon recessive and nuclear nonautonomous. Homokaryotic fmf-1 conidia were purified from a mixed conidial population derived from such a heterokaryon; these conidia failed to function as the male parent, suggesting that the fmf-1  + gene product is not contained in the conidium. In mixed mating-type heterokaryons, formed using tol, fmf-1 participates in ascospore formation and triggers perithecial development. Moreover, to1 suppreses the action of fmf-1 if present in both components of a cross.——These data suggest that (1) fmf-1 acts in the perithecium at some time between fusion of the conidium with the trichogyne and the onset of meiosis; (2) the fmf-1 gene product is not contained in conidia; and (3) both mating types may enter the protoperithecium when a mixed mating-type heterokaryon is used as the male parent.

scholarly journals Altered mating-type identity in the fungus Podospora anserina leads to selfish nuclei, uniparental progeny, and haploid meiosis.

Genetics ◽  
1995 ◽  
Vol 140 (2) ◽  
pp. 493-503 ◽  
Author(s):  
D Zickler ◽  
S Arnaise ◽  
E Coppin ◽  
R Debuchy ◽  
M Picard
Keyword(s):  
Mating Type ◽  
Podospora Anserina ◽  
Wild Type ◽  
Selfish Behavior ◽  
Developmental Patterns ◽  
Filamentous Ascomycete ◽  
Type Identity ◽  
Mat Locus ◽  
Mat Genes

Abstract In wild-type crosses of the filamentous ascomycete Podospora anserina, after fertilization, only nuclei of opposite mating type can form dikaryons that undergo karyogamy and meiosis, producing biparental progeny. To determine the role played by the mating type in these steps, the four mat genes were mutagenized in vitro and introduced into a strain deleted for its mat locus. Genetic and cytological analyses of these mutant strain, crossed to each other and to wild type, showed that mating-type information is required for recognition of nuclear identity during the early steps of sexual reproduction. In crosses with strain carrying a mating-type mutation, two unusual developmental patterns were observed: monokaryotic cells, resulting in haploid meiosis, and uniparental dikaryotic cells providing, after karyogamy and meiosis, a uniparental progeny. Altered mating-type identity leads to selfish behavior of the mutant nucleus: it migrates alone or paired, ignoring its wild-type partner in all mutant x wild-type crosses. This behavior is nucleus-autonomous because, in the same cytoplasm, the wild-type nuclei form only biparental dikaryons. In P. anserina, mat genes are thus required to ensure a biparental dikaryotic state but appear dispensable for later stages, such as meiosis and sporulation.

scholarly journals Size variation of the non-recombining region on the mating-type chromosomes in the fungal Podospora anserina species complex

2021 ◽  
Author(s):  
Fanny E Hartmann ◽  
S Lorena Ament-Velásquez ◽  
Aaron A Vogan ◽  
Valérie Gautier ◽  
Stephanie Le Prieur ◽  
...  
Keyword(s):  
Mating Type ◽  
Sex Chromosomes ◽  
Chromosomal Rearrangements ◽  
Size Variation ◽  
Sequence Divergence ◽  
Podospora Anserina ◽  
Strong Linkage Disequilibrium ◽  
Mating Types ◽  
Type Locus ◽  
Mating Type Locus

Abstract Sex chromosomes often carry large non-recombining regions that can extend progressively over time, generating evolutionary strata of sequence divergence. However, some sex chromosomes display an incomplete suppression of recombination. Large genomic regions without recombination and evolutionary strata have also been documented around fungal mating-type loci, but have been studied in only a few fungal systems. In the model fungus Podospora anserina (Ascomycota, Sordariomycetes), the reference S strain lacks recombination across a 0.8 Mb region around the mating-type locus. The lack of recombination in this region ensures that nuclei of opposite mating types are packaged into a single ascospore (pseudo-homothallic lifecycle). We found evidence for a lack of recombination around the mating-type locus in the genomes of 10 P. anserina strains and six closely related pseudo-homothallic Podospora species. Importantly, the size of the non-recombining region differed between strains and species, as indicated by the heterozygosity levels around the mating-type locus and experimental selfing. The non-recombining region is probably labile and polymorphic, differing in size and precise location within and between species, resulting in occasional, but infrequent, recombination at a given base pair. This view is also supported by the low divergence between mating types, and the lack of strong linkage disequilibrium, chromosomal rearrangements, trans-specific polymorphism and genomic degeneration. We found a pattern suggestive of evolutionary strata in P. pseudocomata. The observed heterozygosity levels indicate low but non-null outcrossing rates in nature in these pseudo-homothallic fungi. This study adds to our understanding of mating-type chromosome evolution and its relationship to mating systems.

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