13 The Mating-Type Genes of the Basidiomycetes

Freihorst, Daniela; Fowler, Thomas J.; Bartholomew, Kirk A.; Raudaskoski, Marjatta; Horton, J. Stephen; Kothe, Erika

doi:10.1007/978-3-319-25844-7_13

Cited by 14 publications

(15 citation statements)

References 128 publications

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“…4). However, their function remains largely elusive, as reports suggest that these are non-mating-type-specific receptors (94, 95), and experimental evidence in S. commune suggest that they are not sufficient per se to induce mating-specific development (96). Many of these non-mating-type-specific receptors are located in the close neighborhood of the P/R locus while others are unlinked (Fig.…”

Section: Breeding Systems In the Basidiomycotamentioning

confidence: 99%

Fungal Sex: The Basidiomycota

et al. 2017

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SUMMARY Fungi of the Basidiomycota, representing major pathogen lineages and mushroom-forming species, exhibit diverse means to achieve sexual reproduction, with particularly varied mechanisms to determine compatibilities of haploid mating partners. For species that require mating between distinct genotypes, discrimination is usually based on both the reciprocal exchange of diffusible mating pheromones, rather than sexes, and the interactions of homeodomain protein signals after cell fusion. Both compatibility factors must be heterozygous in the product of mating, and genetic linkage relationships of the mating pheromone/receptor and homeodomain genes largely determine the complex patterns of mating-type variation. Independent segregation of the two compatibility factors can create four haploid mating genotypes from meiosis, referred to as tetrapolarity. This condition is thought to be ancestral to the basidiomycetes. Alternatively, co-segregation by linkage of the two mating factors, or in some cases the absence of the pheromone-based discrimination, yields only two mating types from meiosis, referred to as bipolarity. Several species are now known to have large and highly rearranged chromosomal regions linked to mating-type genes. At the population level, polymorphism of the mating-type genes is an exceptional aspect of some basidiomycete fungi, where selection under outcrossing for rare, intercompatible allelic variants is thought to be responsible for mating types that may number several thousand. Advances in genome sequencing and assembly are yielding new insights by comparative approaches among and within basidiomycete species, with the promise to resolve the evolutionary origins and dynamics of mating compatibility genetics in this major eukaryotic lineage.

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Section: Breeding Systems In the Basidiomycotamentioning

confidence: 99%

Fungal Sex: The Basidiomycota

et al. 2017

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“…4). However, their function remains largely elusive, because reports suggest that these are non-mating-type-specific receptors (94,95), and experimental evidence from S. commune suggests that they are not sufficient per se to induce mating-specific development (96). Many of these non-mating-type-specific receptors are located in the close neighborhood of the P/R locus, while others are unlinked (Fig.…”

Section: Tetrapolar Systems With Multiple Alleles In the Agaricomycetesmentioning

confidence: 99%

Fungal Sex: The Basidiomycota

et al. 2017

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“…Basidiomycetes generally have many mating types, up to thousands [ 49 ]. In most basidiomycetes, the mating type is determined by two loci: a locus encoding a homeodomain transcription factor (HD), the ‘A’ locus, and a locus encoding pheromones and pheromone receptors (P/R), the ‘B’ locus (see [ 50 ] for an excellent overview). Two nuclei are compatible if the alleles at both mating-type loci are different; therefore, the probability of being compatible is mainly determined by the number of mating types at the locus with the lowest number of variants.…”

Section: The Dikaryon—nuclei Living Apart Together: Genomic Conflict mentioning

confidence: 99%

Unholy marriages and eternal triangles: how competition in the mushroom life cycle can lead to genomic conflict

Vreeburg¹,

Nygren²,

Aanen³

2016

Phil. Trans. R. Soc. B

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In the vast majority of sexual life cycles, fusion between single-celled gametes is directly followed by nuclear fusion, leading to a diploid zygote and a lifelong commitment between two haploid genomes. Mushroom-forming basidiomycetes differ in two key respects. First, the multicellular haploid mating partners are fertilized in their entirety, each cell being a gamete that simultaneously can behave as a female, i.e. contributing the cytoplasm to a zygote by accepting nuclei, and a male gamete, i.e. only donating nuclei to the zygote. Second, after gamete union, the two haploid genomes remain separate so that the main vegetative stage, the dikaryon, has two haploid nuclei per cell. Only when the dikaryon produces mushrooms, do the nuclei fuse to enter a short diploid stage, immediately followed by meiosis and haploid spore formation. So in basidiomycetes, gamete fusion and genome mixing (sex) are separated in time. The ‘living apart together’ of nuclei in the dikaryon maintains some autonomy for nuclei to engage in a relationship with a different nucleus. We show that competition among the two nuclei of the dikaryon for such ‘extramarital affairs’ may lead to genomic conflict by favouring genes beneficial at the level of the nucleus, but deleterious at that of the dikaryon.This article is part of the themed issue ‘Weird sex: the underappreciated diversity of sexual reproduction’.

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13 The Mating-Type Genes of the Basidiomycetes

Cited by 14 publications

References 128 publications

Fungal Sex: The Basidiomycota

Fungal Sex: The Basidiomycota

Fungal Sex: The Basidiomycota

Unholy marriages and eternal triangles: how competition in the mushroom life cycle can lead to genomic conflict

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