Mating-Type Switching in Budding Yeasts, from Flip/Flop Inversion to Cassette Mechanisms

Wolfe, Kenneth H.; Butler, Geraldine

doi:10.1128/mmbr.00007-21

Cited by 6 publications

(4 citation statements)

References 112 publications

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“…However, as with dimorphic species, where sexual offspring only arises from male-female pairs, yeast mating is not random. Compatibility in ascomycetous yeasts is controlled by a single locus for which two alleles, termed idiomorphs, determine the activation of genes that code for either the a - or the α-mating type-specific pheromones and their receptors (Wolfe and Butler 2022 ). In some filamentous Ascomycetes (Pezizomycotina), it is possible to distinguish male and female structures.…”

Section: Introductionmentioning

confidence: 99%

“…Genetically, mother-bud conjugation implies that a species is homothallic, where all sister (mother cell and bud) nuclei are compatible while having identical genomes. Wolfe and Butler ( 2022 ) explained that homothallism arises either when every cell of a culture carries active forms of both mating type alleles, or when cells are capable of mating type switching. The former, termed primary homothallism, has been documented in several species, including D. hansenii , and so we must regard this as an instance where differentiation of the sexes is ontogenetic and independent of mating types.…”

Section: Introductionmentioning

confidence: 99%

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Yeast sexes: mating types do not determine the sexes in Metschnikowia species

Lachance,

Burke,

Nygard

et al. 2024

FEMS Yeast Research

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Although filamentous Ascomycetes may produce structures that are interpreted as male and female gametangia, ascomycetous yeasts are generally not considered to possess male and female sexes. In haplontic yeasts of the genus Metschnikowia, the sexual cycle begins with the fusion of two morphologically identical cells of complementary mating types. Soon after conjugation, a protuberance emerges from one of the conjugants, eventually maturing into an ascus. The originating cell can be regarded as an ascus mother cell, hence as female. We tested the hypothesis that the sexes, female or male, are determined by the mating types. There were good reasons to hypothesize further that mating type α cells are male. In a conceptually simple experiment, we observed the early stages of the mating reaction of mating types differentially labeled with fluorescent concanavalin A conjugates. Three large-spored Metschnikowia species, M. amazonensis, M. continentalis, and M. matae, were examined. In all three, the sexes were found to be independent of mating type, cautioning that the two terms should not be used interchangeably.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Yeast sexes: mating types do not determine the sexes in Metschnikowia species

Lachance,

Burke,

Nygard

et al. 2024

FEMS Yeast Research

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“…Inversion toggling–recurrent re-inversion of a region flanked by inverted repeats–has occurred during the evolution of humans, apes, and other mammals [ 6 , 10 , 11 ]. In some yeast species such as Ogataea polymorpha , an inversion polymorphism controls mating type, and inversion of the MAT region during mating-type switching is a regulated process [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

A widespread inversion polymorphism conserved among Saccharomyces species is caused by recurrent homogenization of a sporulation gene family

et al. 2022

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Saccharomyces genomes are highly collinear and show relatively little structural variation, both within and between species of this yeast genus. We investigated the only common inversion polymorphism known in S. cerevisiae, which affects a 24-kb ‘flip/flop’ region containing 15 genes near the centromere of chromosome XIV. The region exists in two orientations, called reference (REF) and inverted (INV). Meiotic recombination in this region is suppressed in crosses between REF and INV orientation strains such as the BY x RM cross. We find that the inversion polymorphism is at least 17 million years old because it is conserved across the genus Saccharomyces. However, the REF and INV isomers are not ancient alleles but are continually being re-created by re-inversion of the region within each species. Inversion occurs due to continual homogenization of two almost identical 4-kb sequences that form an inverted repeat (IR) at the ends of the flip/flop region. The IR consists of two pairs of genes that are specifically and strongly expressed during the late stages of sporulation. We show that one of these gene pairs, YNL018C/YNL034W, codes for a protein that is essential for spore formation. YNL018C and YNL034W are the founder members of a gene family, Centroid, whose members in other Saccharomycetaceae species evolve fast, duplicate frequently, and are preferentially located close to centromeres. We tested the hypothesis that Centroid genes are a meiotic drive system, but found no support for this idea.

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“…Depending on the strain, yeasts may follow homothallic or heterothallic life cycles, the former being the most common in sporulating wine strains [20,21]. In contrast with heterothallic strains, in which haploid yeast cells of "a" and "α" mating type mate to produce diploid strains, homothallic yeasts, after meiosis, undergo a mating type switch in the daughter bud of the germinating spore, followed by conjugation between daughter and mother cells (endoduplication), thereby yielding homozygous diploid cells (except for the mating type locus) from isolated homothallic spores after sporulation [22].…”

Section: Introductionmentioning

confidence: 99%

Sexually-Driven Combinatorial Diversity in Native Saccharomyces Wine Yeasts

et al. 2022

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Natural diversity represents an inexhaustible source of yeasts for the diversification of wines and the improvement of their properties. In this study, we analysed the genetic diversity of autochthonous Saccharomyces cerevisiae wine yeasts in the Aljarafe of Seville, one of the warmest winemaking regions of Spain. Through multiplex-PCR analysis of five microsatellite markers and RT-PCR determination of the killer genotype, we found 94 different patterns among 150 S. cerevisiae yeast strains isolated from spontaneous fermentation of grape must, thereby representing a highly diverse population. Remarkably, 92% of the isolated strains exhibited high sporulation capacity. Tetrad analysis of sporulating strains rendered a microsatellite marker’s combinatory that mimics patterns observed in the native population, suggesting that the high polymorphism of microsatellite markers found in these wild yeasts might result from sexual reproduction in their natural environment. The identification of unconventional M2/L-A-lus totivirus combinations conferring the killer phenotype also supports this suggestion. One idea behind this study is to determine to what extent the vineyards microbiota in areas with warm climates can provide useful natural yeasts to adapt fermentation processes to the needs imposed by global warming. Analysis of traits of oenological interest in regions potentially affected by global climate changes, such as growth tolerance to ethanol and to sugar stress in the analysed strains, indicated that this broad combinatorial diversity of natural S. cerevisiae yeasts provides a wide range of autochthonous strains with desirable profiles for quality winemaking in warm regions. This combinatorial diversity renders strains with diverse oenological performing abilities. Upon microvinification assays and organoleptic attests, a S. cerevisiae strain with interesting oenological properties has been identified. This result can be considered a successful outcome in industry–academia collaboration.

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Mating-Type Switching in Budding Yeasts, from Flip/Flop Inversion to Cassette Mechanisms

Cited by 6 publications

References 112 publications

Yeast sexes: mating types do not determine the sexes in Metschnikowia species

Yeast sexes: mating types do not determine the sexes in Metschnikowia species

A widespread inversion polymorphism conserved among Saccharomyces species is caused by recurrent homogenization of a sporulation gene family

Sexually-Driven Combinatorial Diversity in Native Saccharomyces Wine Yeasts

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