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Ekdahl LI, Salcedo JA, Dungan MM, Mason DV, Myagmarsuren D, Murphy HA. Selection on plastic adherence leads to hyper-multicellular strains and incidental virulence in the budding yeast. eLife 2023; 12:e81056. [PMID: 37916911 PMCID: PMC10764007 DOI: 10.7554/elife.81056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 11/01/2023] [Indexed: 11/03/2023] Open
Abstract
Many disease-causing microbes are not obligate pathogens; rather, they are environmental microbes taking advantage of an ecological opportunity. The existence of microbes whose life cycle does not require a host and are not normally pathogenic, yet are well-suited to host exploitation, is an evolutionary puzzle. One hypothesis posits that selection in the environment may favor traits that incidentally lead to pathogenicity and virulence, or serve as pre-adaptations for survival in a host. An example of such a trait is surface adherence. To experimentally test the idea of 'accidental virulence', replicate populations of Saccharomyces cerevisiae were evolved to attach to a plastic bead for hundreds of generations. Along with plastic adherence, two multicellular phenotypes- biofilm formation and flor formation- increased; another phenotype, pseudohyphal growth, responded to the nutrient limitation. Thus, experimental selection led to the evolution of highly-adherent, hyper-multicellular strains. Wax moth larvae injected with evolved hyper-multicellular strains were significantly more likely to die than those injected with evolved non-multicellular strains. Hence, selection on plastic adherence incidentally led to the evolution of enhanced multicellularity and increased virulence. Our results support the idea that selection for a trait beneficial in the open environment can inadvertently generate opportunistic, 'accidental' pathogens.
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Affiliation(s)
- Luke I Ekdahl
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Juliana A Salcedo
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Matthew M Dungan
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | - Despina V Mason
- Department of Biology, College of William and MaryWilliamsburgUnited States
| | | | - Helen A Murphy
- Department of Biology, College of William and MaryWilliamsburgUnited States
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2
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Collins JH, Kunyeit L, Weintraub S, Sharma N, White C, Haq N, Anu-Appaiah KA, Rao RP, Young EM. Genetic basis for probiotic yeast phenotypes revealed by nanopore sequencing. G3 (BETHESDA, MD.) 2023; 13:jkad093. [PMID: 37103477 PMCID: PMC10411601 DOI: 10.1093/g3journal/jkad093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 01/31/2023] [Accepted: 04/14/2023] [Indexed: 04/28/2023]
Abstract
Probiotic yeasts are emerging as preventative and therapeutic solutions for disease. Often ingested via cultured foods and beverages, they can survive the harsh conditions of the gastrointestinal tract and adhere to it, where they provide nutrients and inhibit pathogens like Candida albicans. Yet, little is known of the genomic determinants of these beneficial traits. To this end, we have sequenced 2 food-derived probiotic yeast isolates that mitigate fungal infections. We find that the first strain, KTP, is a strain of Saccharomyces cerevisiae within a small clade that lacks any apparent ancestry from common European/wine S. cerevisiae strains. Significantly, we show that S. cerevisiae KTP genes involved in general stress, pH tolerance, and adherence are markedly different from S. cerevisiae S288C but are similar to the commercial probiotic yeast species S. boulardii. This suggests that even though S. cerevisiae KTP and S. boulardii are from different clades, they may achieve probiotic effect through similar genetic mechanisms. We find that the second strain, ApC, is a strain of Issatchenkia occidentalis, one of the few of this family of yeasts to be sequenced. Because of the dissimilarity of its genome structure and gene organization, we infer that I. occidentalis ApC likely achieves a probiotic effect through a different mechanism than the Saccharomyces strains. Therefore, this work establishes a strong genetic link among probiotic Saccharomycetes, advances the genomics of Issatchenkia yeasts, and indicates that probiotic activity is not monophyletic and complimentary mixtures of probiotics could enhance health benefits beyond a single species.
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Affiliation(s)
- Joseph H Collins
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Lohith Kunyeit
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
- Department of Microbiology and Fermentation Technology, CSIR—Central Food Technological Research Institute (CFTRI), Mysore, Karnataka 570020, India
| | - Sarah Weintraub
- Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Nilesh Sharma
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Charlotte White
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Nabeeha Haq
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - K A Anu-Appaiah
- Department of Microbiology and Fermentation Technology, CSIR—Central Food Technological Research Institute (CFTRI), Mysore, Karnataka 570020, India
| | - Reeta P Rao
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Eric M Young
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USA
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3
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Capp J, Thomas F, Marusyk A, M. Dujon A, Tissot S, Gatenby R, Roche B, Ujvari B, DeGregori J, Brown JS, Nedelcu AM. The paradox of cooperation among selfish cancer cells. Evol Appl 2023; 16:1239-1256. [PMID: 37492150 PMCID: PMC10363833 DOI: 10.1111/eva.13571] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 05/19/2023] [Accepted: 06/06/2023] [Indexed: 07/27/2023] Open
Abstract
It is traditionally assumed that during cancer development, tumor cells abort their initially cooperative behavior (i.e., cheat) in favor of evolutionary strategies designed solely to enhance their own fitness (i.e., a "selfish" life style) at the expense of that of the multicellular organism. However, the growth and progress of solid tumors can also involve cooperation among these presumed selfish cells (which, by definition, should be noncooperative) and with stromal cells. The ultimate and proximate reasons behind this paradox are not fully understood. Here, in the light of current theories on the evolution of cooperation, we discuss the possible evolutionary mechanisms that could explain the apparent cooperative behaviors among selfish malignant cells. In addition to the most classical explanations for cooperation in cancer and in general (by-product mutualism, kin selection, direct reciprocity, indirect reciprocity, network reciprocity, group selection), we propose the idea that "greenbeard" effects are relevant to explaining some cooperative behaviors in cancer. Also, we discuss the possibility that malignant cooperative cells express or co-opt cooperative traits normally expressed by healthy cells. We provide examples where considerations of these processes could help understand tumorigenesis and metastasis and argue that this framework provides novel insights into cancer biology and potential strategies for cancer prevention and treatment.
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Affiliation(s)
- Jean‐Pascal Capp
- Toulouse Biotechnology InstituteUniversity of Toulouse, INSA, CNRS, INRAEToulouseFrance
| | - Frédéric Thomas
- CREEC, MIVEGECUniversity of Montpellier, CNRS, IRDMontpellierFrance
| | - Andriy Marusyk
- Department of Cancer PhysiologyH Lee Moffitt Cancer Center and Research InstituteTampaFloridaUSA
| | - Antoine M. Dujon
- Centre for Integrative Ecology, School of Life and Environmental SciencesDeakin UniversityGeelongVictoriaAustralia
| | - Sophie Tissot
- Department of Biochemistry and Molecular GeneticsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Robert Gatenby
- Department of Cancer PhysiologyH Lee Moffitt Cancer Center and Research InstituteTampaFloridaUSA
| | - Benjamin Roche
- Department of Biochemistry and Molecular GeneticsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Beata Ujvari
- Centre for Integrative Ecology, School of Life and Environmental SciencesDeakin UniversityGeelongVictoriaAustralia
| | - James DeGregori
- Department of Biochemistry and Molecular GeneticsUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Joel S. Brown
- Department of Cancer PhysiologyH Lee Moffitt Cancer Center and Research InstituteTampaFloridaUSA
| | - Aurora M. Nedelcu
- Department of BiologyUniversity of New BrunswickFrederictonNew BrunswickCanada
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4
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Gene loss and compensatory evolution promotes the emergence of morphological novelties in budding yeast. Nat Ecol Evol 2022; 6:763-773. [PMID: 35484218 DOI: 10.1038/s41559-022-01730-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 03/10/2022] [Indexed: 01/05/2023]
Abstract
Deleterious mutations are generally considered to be irrelevant for morphological evolution. However, they could be compensated by conditionally beneficial mutations, thereby providing access to new adaptive paths. Here we use high-dimensional phenotyping of laboratory-evolved budding yeast lineages to demonstrate that new cellular morphologies emerge exceptionally rapidly as a by-product of gene loss and subsequent compensatory evolution. Unexpectedly, the capacities for invasive growth, multicellular aggregation and biofilm formation also spontaneously evolve in response to gene loss. These multicellular phenotypes can be achieved by diverse mutational routes and without reactivating the canonical regulatory pathways. These ecologically and clinically relevant traits originate as pleiotropic side effects of compensatory evolution and have no obvious utility in the laboratory environment. The extent of morphological diversity in the evolved lineages is comparable to that of natural yeast isolates with diverse genetic backgrounds and lifestyles. Finally, we show that both the initial gene loss and subsequent compensatory mutations contribute to new morphologies, with their synergistic effects underlying specific morphological changes. We conclude that compensatory evolution is a previously unrecognized source of morphological diversity and phenotypic novelties.
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5
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Saguez C, Viterbo D, Descorps-Declère S, Cormack BP, Dujon B, Richard GF. Functional variability in adhesion and flocculation of yeast megasatellite genes. Genetics 2022; 221:iyac042. [PMID: 35274698 PMCID: PMC9071537 DOI: 10.1093/genetics/iyac042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/07/2022] [Indexed: 11/14/2022] Open
Abstract
Megasatellites are large tandem repeats found in all fungal genomes but especially abundant in the opportunistic pathogen Candida glabrata. They are encoded in genes involved in cell-cell interactions, either between yeasts or between yeast and human cells. In the present work, we have been using an iterative genetic system to delete several Candida glabrata megasatellite-containing genes and found that 2 of them were positively involved in adhesion to epithelial cells, whereas 3 genes negatively controlled adhesion. Two of the latter, CAGL0B05061g or CAGL0A04851g, were also negative regulators of yeast-to-yeast adhesion, making them central players in controlling Candida glabrata adherence properties. Using a series of synthetic Saccharomyces cerevisiae strains in which the FLO1 megasatellite was replaced by other tandem repeats of similar length but different sequences, we showed that the capacity of a strain to flocculate in liquid culture was unrelated to its capacity to adhere to epithelial cells or to invade agar. Finally, to understand how megasatellites were initially created and subsequently expanded, an experimental evolution system was set up, in which modified yeast strains containing different megasatellite seeds were grown in bioreactors for more than 200 generations and selected for their ability to sediment at the bottom of the culture tube. Several flocculation-positive mutants were isolated. Functionally relevant mutations included general transcription factors as well as a 230-kbp segmental duplication.
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Affiliation(s)
- Cyril Saguez
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
- Present address: Abolis Biotechnologies, 5 Rue Henri Desbruères, Evry 91030, France
| | - David Viterbo
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
| | - Stéphane Descorps-Declère
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
- Institut Pasteur, Bioinformatics and Biostatistics Hub, Department of Computational Biology, Paris F-75015, France
| | - Brendan P Cormack
- Department of Molecular Biology & Genetics, Johns Hopkins University, Baltimore, Maryland 21287, USA
| | - Bernard Dujon
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
| | - Guy-Franck Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Genétique des Génomes, Paris F-75015, France
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6
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Aggeli D, Marad DA, Liu X, Buskirk SW, Levy SF, Lang GI. Overdominant and partially dominant mutations drive clonal adaptation in diploid Saccharomyces cerevisiae. Genetics 2022; 221:6569837. [PMID: 35435209 PMCID: PMC9157133 DOI: 10.1093/genetics/iyac061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 04/06/2022] [Indexed: 11/14/2022] Open
Abstract
Identification of adaptive targets in experimental evolution typically relies on extensive replication and genetic reconstruction. An alternative approach is to directly assay all mutations in an evolved clone by generating pools of segregants that contain random combinations of evolved mutations. Here, we apply this method to six Saccharomyces cerevisiae clones isolated from four diploid populations that were clonally evolved for 2,000 generations in rich glucose medium. Each clone contains 17-26 mutations relative to the ancestor. We derived intermediate genotypes between the founder and the evolved clones by bulk mating sporulated cultures of the evolved clones to a barcoded haploid version of the ancestor. We competed the resulting barcoded diploids en masse and quantified fitness in the experimental and alternative environments by barcode sequencing. We estimated average fitness effects of evolved mutations using barcode-based fitness assays and whole genome sequencing for a subset of segregants. In contrast to our previous work with haploid evolved clones, we find that diploids carry fewer beneficial mutations, with modest fitness effects (up to 5.4%) in the environment in which they arose. In agreement with theoretical expectations, reconstruction experiments show that all mutations with a detectable fitness effect manifest some degree of dominance over the ancestral allele, and most are overdominant. Genotypes with lower fitness effects in alternative environments allowed us to identify conditions that drive adaptation in our system.
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Affiliation(s)
- Dimitra Aggeli
- Department of Biological Sciences, Lehigh University, Bethlehem, PA18015, USA
| | - Daniel A Marad
- Department of Biological Sciences, Lehigh University, Bethlehem, PA18015, USA
| | - Xianan Liu
- Joint Initiative for Metrology in Biology, SLAC National Accelerator Laboratory, Stanford University, Stanford, CA94025, USA
| | - Sean W Buskirk
- Department of Biological Sciences, Lehigh University, Bethlehem, PA18015, USA.,Department of Biology, West Chester University, West Chester, PA19383, USA
| | - Sasha F Levy
- Joint Initiative for Metrology in Biology, SLAC National Accelerator Laboratory, Stanford University, Stanford, CA94025, USA
| | - Gregory I Lang
- Department of Biological Sciences, Lehigh University, Bethlehem, PA18015, USA
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7
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Forehand AL, Myagmarsuren D, Chen Z, Murphy HA. Variation in pH gradients and FLO11 expression in mat biofilms from environmental isolates of the yeast Saccharomyces cerevisiae. Microbiologyopen 2022; 11:e1277. [PMID: 35478280 PMCID: PMC9059236 DOI: 10.1002/mbo3.1277] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 03/10/2022] [Indexed: 12/15/2022] Open
Abstract
Saccharomyces cerevisiae produces a multicellular phenotype, known as a mat, on a semi-solid medium. This biofilm phenotype was first described in the lab strain Σ1278b and has been analyzed mostly in this same background. Yeast cells form a mat by spreading across the medium and adhering to each other and the surface, in part through the variegated expression of the cell adhesion, FLO11. This process creates a characteristic floral pattern and generates pH and glucose gradients outward from the center of the mat. Mats are encapsulated in a liquid which may aid in surface spreading and diffusion. Here, we examine thirteen environmental isolates that vary visually in the phenotype. We predicted that mat properties were universal and increased morphological complexity would be associated with more extreme trait values. Our results showed that pH varied significantly among strains, but was not correlated to mat complexity. Only two isolates generated significant liquid boundaries and neither produced visually complex mats. In five isolates, we tracked the initiation of FLO11 using green fluorescent protein (GFP) under the control of the endogenous promoter. Strains varied in when and how much GFP was detected, with increased signal associated with increased morphological complexity. Generally, the signal was strongest in the center of the mat and absent at the expanding edge. Our results show that traits discovered in one background vary and exist independently of mat complexity in natural isolates. The environment may favor different sets of traits, which could have implications for how this yeast adapts to its many ecological niches.
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Affiliation(s)
- Amy L. Forehand
- Department of BiologyWilliam & MaryWilliamsburgVirginiaUSA,Present address:
Amy L. Forehand, Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | | | - Ziyan Chen
- Department of BiologyWilliam & MaryWilliamsburgVirginiaUSA,Present address:
Ziyan Chen, School of MedicineUniversity of VirginiaCharlottesvilleVirginiaUSA
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8
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Stress Resistance and Adhesive Properties of Commercial Flor and Wine Strains, and Environmental Isolates of Saccharomyces cerevisiae. FERMENTATION-BASEL 2021. [DOI: 10.3390/fermentation7030188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flor strains of Saccharomyces cerevisiae represent a special group of yeasts used for producing biologically aged wines. We analyzed the collection of commercial wine and flor yeast strains, as well as environmental strains isolated from the surface of grapes growing in vineyards, for resistance to abiotic stresses, adhesive properties, and the ability to form a floating flor. The degree of resistance of commercial strains to ethanol, acetaldehyde, and hydrogen peroxide was generally not higher than that of environmental isolates, some of which had high resistance to the tested stress agents. The relatively low degree of stress resistance of flor strains can be explained both by the peculiarities of their adaptive mechanisms and by differences in the nature of their exposure to various types of stress in the course of biological wine aging and under the experimental conditions we used. The hydrophobicity and adhesive properties of cells were determined by the efficiency of adsorption to polystyrene and the distribution of cells between the aqueous and organic phases. Flor strains were distinguished by a higher degree of hydrophobicity of the cell surface and an increased ability to adhere to polystyrene. A clear correlation between biofilm formation and adhesive properties was also observed for environmental yeast isolates. The overall results of this study indicate that relatively simple tests for cell hydrophobicity can be used for the rapid screening of new candidate flor strains in yeast culture collections and among environmental isolates.
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9
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High Foam Phenotypic Diversity and Variability in Flocculant Gene Observed for Various Yeast Cell Surfaces Present as Industrial Contaminants. FERMENTATION-BASEL 2021. [DOI: 10.3390/fermentation7030127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Many contaminant yeast strains that survive inside fuel ethanol industrial vats show detrimental cell surface phenotypes. These harmful effects may include filamentation, invasive growth, flocculation, biofilm formation, and excessive foam production. Previous studies have linked some of these phenotypes to the expression of FLO genes, and the presence of gene length polymorphisms causing the expansion of FLO gene size appears to result in stronger flocculation and biofilm formation phenotypes. We performed here a molecular analysis of FLO1 and FLO11 gene polymorphisms present in contaminant strains of Saccharomyces cerevisiae from Brazilian fuel ethanol distilleries showing vigorous foaming phenotypes during fermentation. The size variability of these genes was correlated with cellular hydrophobicity, flocculation, and highly foaming phenotypes in these yeast strains. Our results also showed that deleting the primary activator of FLO genes (the FLO8 gene) from the genome of a contaminant and highly foaming industrial strain avoids complex foam formation, flocculation, invasive growth, and biofilm production by the engineered (flo8∆::BleR/flo8Δ::kanMX) yeast strain. Thus, the characterization of highly foaming yeasts and the influence of FLO8 in this phenotype open new perspectives for yeast strain engineering and optimization in the sugarcane fuel-ethanol industry.
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10
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Koonthongkaew J, Toyokawa Y, Ohashi M, Large CRL, Dunham MJ, Takagi H. Effect of the Ala234Asp replacement in mitochondrial branched-chain amino acid aminotransferase on the production of BCAAs and fusel alcohols in yeast. Appl Microbiol Biotechnol 2020. [PMID: 32776205 DOI: 10.1101/2020.06.26.166157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In the yeast Saccharomyces cerevisiae, the mitochondrial branched-chain amino acid (BCAA) aminotransferase Bat1 plays an important role in the synthesis of BCAAs (valine, leucine, and isoleucine). Our upcoming study (Large et al. bioRχiv. 10.1101/2020.06.26.166157, Large et al. 2020) will show that the heterozygous tetraploid beer yeast strain, Wyeast 1056, which natively has a variant causing one amino acid substitution of Ala234Asp in Bat1 on one of the four chromosomes, produced higher levels of BCAA-derived fusel alcohols in the brewer's wort medium than a derived strain lacking this mutation. Here, we investigated the physiological role of the A234D variant Bat1 in S. cerevisiae. Both bat1∆ and bat1A234D cells exhibited the same phenotypes relative to the wild-type Bat1 strain-namely, a repressive growth rate in the logarithmic phase; decreases in intracellular valine and leucine content in the logarithmic and stationary growth phases, respectively; an increase in fusel alcohol content in culture medium; and a decrease in the carbon dioxide productivity. These results indicate that amino acid change from Ala to Asp at position 234 led to a functional impairment of Bat1, although homology modeling suggests that Asp234 in the variant Bat1 did not inhibit enzymatic activity directly. KEY POINTS: • Yeast cells expressing Bat1A234D exhibited a slower growth phenotype. • The Val and Leu levels were decreased in yeast cells expressing Bat1A234D. • The A234D substitution causes a loss-of-function in Bat1. • The A234D substitution in Bat1 increased fusel alcohol production in yeast cells.
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Affiliation(s)
- Jirasin Koonthongkaew
- Division of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Yoichi Toyokawa
- Division of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Masataka Ohashi
- Nara Prefecture Institute of Industrial Development, 129-1 Kashiwagi-cho, Nara, Nara, 630-8031, Japan
| | - Christopher R L Large
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Hiroshi Takagi
- Division of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan.
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11
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Barré BP, Hallin J, Yue JX, Persson K, Mikhalev E, Irizar A, Holt S, Thompson D, Molin M, Warringer J, Liti G. Intragenic repeat expansion in the cell wall protein gene HPF1 controls yeast chronological aging. Genome Res 2020; 30:697-710. [PMID: 32277013 PMCID: PMC7263189 DOI: 10.1101/gr.253351.119] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 04/09/2020] [Indexed: 01/02/2023]
Abstract
Aging varies among individuals due to both genetics and environment, but the underlying molecular mechanisms remain largely unknown. Using a highly recombined Saccharomyces cerevisiae population, we found 30 distinct quantitative trait loci (QTLs) that control chronological life span (CLS) in calorie-rich and calorie-restricted environments and under rapamycin exposure. Calorie restriction and rapamycin extended life span in virtually all genotypes but through different genetic variants. We tracked the two major QTLs to the cell wall glycoprotein genes FLO11 and HPF1 We found that massive expansion of intragenic tandem repeats within the N-terminal domain of HPF1 was sufficient to cause pronounced life span shortening. Life span impairment by HPF1 was buffered by rapamycin but not by calorie restriction. The HPF1 repeat expansion shifted yeast cells from a sedentary to a buoyant state, thereby increasing their exposure to surrounding oxygen. The higher oxygenation altered methionine, lipid, and purine metabolism, and inhibited quiescence, which explains the life span shortening. We conclude that fast-evolving intragenic repeat expansions can fundamentally change the relationship between cells and their environment with profound effects on cellular lifestyle and longevity.
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Affiliation(s)
| | - Johan Hallin
- Université Côte d'Azur, CNRS, INSERM, IRCAN, 06107 Nice, France
| | - Jia-Xing Yue
- Université Côte d'Azur, CNRS, INSERM, IRCAN, 06107 Nice, France
| | - Karl Persson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41390 Gothenburg, Sweden
| | | | | | - Sylvester Holt
- Université Côte d'Azur, CNRS, INSERM, IRCAN, 06107 Nice, France
| | - Dawn Thompson
- Ginkgo Bioworks Incorporated, Boston, Massachusetts 02210, USA
| | - Mikael Molin
- Department of Biology and Biological Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41390 Gothenburg, Sweden
| | - Gianni Liti
- Université Côte d'Azur, CNRS, INSERM, IRCAN, 06107 Nice, France
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12
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Molecular signatures of aneuploidy-driven adaptive evolution. Nat Commun 2020; 11:588. [PMID: 32001709 PMCID: PMC6992709 DOI: 10.1038/s41467-019-13669-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 11/15/2019] [Indexed: 02/06/2023] Open
Abstract
Alteration of normal ploidy (aneuploidy) can have a number of opposing effects, such as unbalancing protein abundances and inhibiting cell growth but also accelerating genetic diversification and rapid adaptation. The interplay of these detrimental and beneficial effects remains puzzling. Here, to understand how cells develop tolerance to aneuploidy, we subject disomic (i.e. with an extra chromosome copy) strains of yeast to long-term experimental evolution under strong selection, by forcing disomy maintenance and daily population dilution. We characterize mutations, karyotype alterations and gene expression changes, and dissect the associated molecular strategies. Cells with different extra chromosomes accumulated mutations at distinct rates and displayed diverse adaptive events. They tended to evolve towards normal ploidy through chromosomal DNA loss and gene expression changes. We identify genes with recurrent mutations and altered expression in multiple lines, revealing a variant that improves growth under genotoxic stresses. These findings support rapid evolvability of disomic strains that can be used to characterize fitness effects of mutations under different stress conditions. Aneuploidy (abnormal chromosome number) can enable rapid adaptation to stress conditions, but it also entails fitness costs from gene imbalance. Here, the authors experimentally evolve yeast while forcing maintenance of aneuploidy to identify the mechanisms that promote tolerance of aneuploidy.
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13
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Oppler ZJ, Parrish ME, Murphy HA. Variation at an adhesin locus suggests sociality in natural populations of the yeast Saccharomyces cerevisiae. Proc Biol Sci 2019; 286:20191948. [PMID: 31615361 PMCID: PMC6834051 DOI: 10.1098/rspb.2019.1948] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Microbes engage in numerous social behaviours that are critical for survival and reproduction, and that require individuals to act as a collective. Various mechanisms ensure that collectives are composed of related, cooperating cells, thus allowing for the evolution and stability of these traits, and for selection to favour traits beneficial to the collective. Since microbes are difficult to observe directly, sociality in natural populations can instead be investigated using evolutionary genetic signatures, as social loci can be evolutionary hotspots. The budding yeast has been studied for over a century, yet little is known about its social behaviour in nature. Flo11 is a highly regulated cell adhesin required for most laboratory social phenotypes; studies suggest it may function in cell recognition and its heterogeneous expression may be adaptive for collectives such as biofilms. We investigated this locus and found positive selection in the areas implicated in cell-cell interaction, suggesting selection for kin discrimination. We also found balancing selection at an upstream activation site, suggesting selection on the level of variegated gene expression. Our results suggest this model yeast is surprisingly social in natural environments and is probably engaging in various forms of sociality. By using genomic data, this research provides a glimpse of otherwise unobservable interactions.
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Affiliation(s)
- Zachary J Oppler
- Department of Biology, William & Mary, PO Box 8795, Williamsburg, VA 23187-8795, USA
| | - Meadow E Parrish
- Department of Biology, William & Mary, PO Box 8795, Williamsburg, VA 23187-8795, USA
| | - Helen A Murphy
- Department of Biology, William & Mary, PO Box 8795, Williamsburg, VA 23187-8795, USA
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14
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James TY, Michelotti LA, Glasco AD, Clemons RA, Powers RA, James ES, Simmons DR, Bai F, Ge S. Adaptation by Loss of Heterozygosity in Saccharomyces cerevisiae Clones Under Divergent Selection. Genetics 2019; 213:665-683. [PMID: 31371407 PMCID: PMC6781901 DOI: 10.1534/genetics.119.302411] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/29/2019] [Indexed: 01/14/2023] Open
Abstract
Loss of heterozygosity (LOH) is observed during vegetative growth and reproduction of diploid genotypes through mitotic crossovers, aneuploidy caused by nondisjunction, and gene conversion. We aimed to test the role that LOH plays during adaptation of two highly heterozygous Saccharomyces cerevisiae genotypes to multiple environments over a short time span in the laboratory. We hypothesized that adaptation would be observed through parallel LOH events across replicate populations. Using genome resequencing of 70 clones, we found that LOH was widespread with 5.2 LOH events per clone after ∼500 generations. The most common mode of LOH was gene conversion (51%) followed by crossing over consistent with either break-induced replication or double Holliday junction resolution. There was no evidence that LOH involved nondisjunction of whole chromosomes. We observed parallel LOH in both an environment-specific and environment-independent manner. LOH largely involved recombining existing variation between the parental genotypes, but also was observed after de novo, presumably beneficial, mutations occurred in the presence of canavanine, a toxic analog of arginine. One highly parallel LOH event involved the ENA salt efflux pump locus on chromosome IV, which showed repeated LOH to the allele from the European parent, an allele originally derived by introgression from S. paradoxus Using CRISPR-engineered LOH we showed that the fitness advantage provided by this single LOH event was 27%. Overall, we found extensive evidence that LOH could be adaptive and is likely to be a greater source of initial variation than de novo mutation for rapid evolution of diploid genotypes.
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Affiliation(s)
- Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lucas A Michelotti
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Alexander D Glasco
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Rebecca A Clemons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Robert A Powers
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Ellen S James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - D Rabern Simmons
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Fengyan Bai
- Institute of Microbiology, Chinese Academy of Sciences, State Key Laboratory of Mycology, Chaoyang District, Beijing 100101, China
| | - Shuhua Ge
- Technology Development and Transfer Center, Institute of Microbiology, Chinese Academy of Sciences, Chaoyang District, Beijing 100029, China
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15
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Abstract
Understanding how and why cells cooperate to form multicellular organisms is a central aim of evolutionary biology. Multicellular groups can form through clonal development (where daughter cells stick to mother cells after division) or by aggregation (where cells aggregate to form groups). These different ways of forming groups directly affect relatedness between individual cells, which in turn can influence the degree of cooperation and conflict within the multicellular group. It is hard to study the evolution of multicellularity by focusing only on obligately multicellular organisms, like complex animals and plants, because the factors that favour multicellular cooperation cannot be disentangled, as cells cannot survive and reproduce independently. We support the use of Saccharomyces cerevisiae as an ideal model for studying the very first stages of the evolution of multicellularity. This is because it can form multicellular groups both clonally and through aggregation and uses a family of proteins called ‘flocculins’ that determine the way in which groups form, making it particularly amenable to laboratory experiments. We briefly review current knowledge about multicellularity in S. cerevisiae and then propose a framework for making predictions about the evolution of multicellular phenotypes in yeast based on social evolution theory. We finish by explaining how S. cerevisiae is a particularly useful experimental model for the analysis of open questions concerning multicellularity.
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Affiliation(s)
- R M Fisher
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - B Regenberg
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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16
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Variation in Filamentous Growth and Response to Quorum-Sensing Compounds in Environmental Isolates of Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2019; 9:1533-1544. [PMID: 30862622 PMCID: PMC6505140 DOI: 10.1534/g3.119.400080] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In fungi, filamentous growth is a major developmental transition that occurs in response to environmental cues. In diploid Saccharomyces cerevisiae, it is known as pseudohyphal growth and presumed to be a foraging mechanism. Rather than unicellular growth, multicellular filaments composed of elongated, attached cells spread over and into surfaces. This morphogenetic switch can be induced through quorum sensing with the aromatic alcohols phenylethanol and tryptophol. Most research investigating pseudohyphal growth has been conducted in a single lab background, Σ1278b. To investigate the natural variation in this phenotype and its induction, we assayed the diverse 100-genomes collection of environmental isolates. Using computational image analysis, we quantified the production of pseudohyphae and observed a large amount of variation. Population origin was significantly associated with pseudohyphal growth, with the West African population having the most. Surprisingly, most strains showed little or no response to exogenous phenylethanol or tryptophol. We also investigated the amount of natural genetic variation in pseudohyphal growth using a mapping population derived from a highly-heterozygous clinical isolate that contained as much phenotypic variation as the environmental panel. A bulk-segregant analysis uncovered five major peaks with candidate loci that have been implicated in the Σ1278b background. Our results indicate that the filamentous growth response is a generalized, highly variable phenotype in natural populations, while response to quorum sensing molecules is surprisingly rare. These findings highlight the importance of coupling studies in tractable lab strains with natural isolates in order to understand the relevance and distribution of well-studied traits.
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17
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Layers of Cryptic Genetic Variation Underlie a Yeast Complex Trait. Genetics 2019; 211:1469-1482. [PMID: 30787041 PMCID: PMC6456305 DOI: 10.1534/genetics.119.301907] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/14/2019] [Indexed: 01/13/2023] Open
Abstract
To better understand cryptic genetic variation, Lee et al. comprehensively map the genetic basis of a trait that is typically suppressed in a yeast cross. By determining how three different genetic perturbations give rise... Cryptic genetic variation may be an important contributor to heritable traits, but its extent and regulation are not fully understood. Here, we investigate the cryptic genetic variation underlying a Saccharomyces cerevisiae colony phenotype that is typically suppressed in a cross of the laboratory strain BY4716 (BY) and a derivative of the clinical isolate 322134S (3S). To do this, we comprehensively dissect the trait’s genetic basis in the BYx3S cross in the presence of three different genetic perturbations that enable its expression. This allows us to detect and compare the specific loci that interact with each perturbation to produce the trait. In total, we identify 21 loci, all but one of which interact with just a subset of the perturbations. Beyond impacting which loci contribute to the trait, the genetic perturbations also alter the extent of additivity, epistasis, and genotype–environment interaction among the detected loci. Additionally, we show that the single locus interacting with all three perturbations corresponds to the coding region of the cell surface gene FLO11. While nearly all of the other remaining loci influence FLO11 transcription in cis or trans, the perturbations tend to interact with loci in different pathways and subpathways. Our work shows how layers of cryptic genetic variation can influence complex traits. Here, these layers mainly represent different regulatory inputs into the transcription of a single key gene.
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18
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Tek EL, Sundstrom JF, Gardner JM, Oliver SG, Jiranek V. Evaluation of the ability of commercial wine yeasts to form biofilms (mats) and adhere to plastic: implications for the microbiota of the winery environment. FEMS Microbiol Ecol 2019; 94:4831476. [PMID: 29394344 DOI: 10.1093/femsec/fix188] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
Commercially available active dried wine yeasts are regularly used by winemakers worldwide to achieve reliable fermentations and obtain quality wine. This practice has led to increased evidence of traces of commercial wine yeast in the vineyard, winery and uninoculated musts. The mechanism(s) that enables commercial wine yeast to persist in the winery environment and the influence to native microbial communities on this persistence is poorly understood. This study has investigated the ability of commercial wine yeasts to form biofilms and adhere to plastic. The results indicate that the biofilms formed by commercial yeasts consist of cells with a combination of different lifestyles (replicative and non-replicative) and growth modes including invasive growth, bud elongation, sporulation and a mat sectoring-like phenotype. Invasive growth was greatly enhanced on grape pulp regardless of strain, while adhesion on plastic varied between strains. The findings suggest a possible mechanism that allows commercial yeast to colonise and survive in the winery environment, which may have implications for the indigenous microbiota profile as well as the population profile in uninoculated fermentations if their dissemination is not controlled.
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Affiliation(s)
- Ee Lin Tek
- Department of Wine and Food Science, School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Joanna F Sundstrom
- Department of Wine and Food Science, School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Jennifer M Gardner
- Department of Wine and Food Science, School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia
| | - Stephen G Oliver
- Department of Biochemistry & Cambridge Systems Biology Centre, University of Cambridge, Cambridge CB2 1GA, UK
| | - Vladimir Jiranek
- Department of Wine and Food Science, School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Urrbrae, South Australia 5064, Australia.,Australian Research Council Training Centre for Innovative Wine Production, University of Adelaide, Waite Campus, Australia
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19
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Going with the Flo: The Role of Flo11-Dependent and Independent Interactions in Yeast Mat Formation. J Fungi (Basel) 2018; 4:jof4040132. [PMID: 30544497 PMCID: PMC6308949 DOI: 10.3390/jof4040132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/23/2018] [Accepted: 11/29/2018] [Indexed: 01/20/2023] Open
Abstract
Strains of the bakers’ yeast Saccharomyces cerevisiae that are able to generate a multicellular structure called a mat on low percentage (0.3%) agar plates are given a selective advantage over strains that cannot exhibit this phenotype. This environment may exhibit some similarities to the rotting fruit on which S. cerevisiae often grows in nature. Mat formation occurs when the cells spread over the plate as they grow, and cells in the center of the biofilm aggregate to form multicellular structures that resemble a floral pattern. This multicellular behavior is dependent on the cell surface flocculin Flo11. This review covers recent information on the structure of Flo11 and how this likely impacts mat formation as well as how variegated expression of Flo11 influences mat formation. Finally, it also discusses several Flo11-independent genetic factors that control mat formation, such as vacuolar protein sorting (VPS) genes, cell wall signaling components, and heat shock proteins.
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20
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David-Vaizant V, Alexandre H. Flor Yeast Diversity and Dynamics in Biologically Aged Wines. Front Microbiol 2018; 9:2235. [PMID: 30319565 PMCID: PMC6167421 DOI: 10.3389/fmicb.2018.02235] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/03/2018] [Indexed: 11/29/2022] Open
Abstract
Wine biological aging is characterized by the development of yeast strains that form a biofilm on the wine surface after alcoholic fermentation. These yeasts, known as flor yeasts, form a velum that protects the wine from oxidation during aging. Thirty-nine velums aged from 1 to 6 years were sampled from “Vin jaune” from two different cellars. We show for the first time that these velums possess various aspects in term of color and surface aspects. Surprisingly, the heterogeneous velums are mostly composed of one species, S. cerevisiae. Scanning electron microscope observations of these velums revealed unprecedented biofilm structures and various yeast morphologies formed by the sole S. cerevisiae species. Our results highlight that different strains of Saccharomyces are present in these velums. Unexpectedly, in the same velum, flor yeast strain succession occurred during aging, supporting the assumption that environmental changes are responsible for these shifts. Despite numerous sample wine analyses, very few flor yeasts could be isolated from wine following alcoholic fermentation, suggesting that flor yeast development results from the colonization of yeast present in the aging cellar. We analyzed the FLO11 and ICR1 sequence of different S. cerevisiae strains in order to understand how the same strain of S. cerevisiae could form various types of biofilm. Among the strains analyzed, some were heterozygote at the FLO11 locus, while others presented two different alleles of ICR1 (wild type and a 111 bp deletion). We could not find a strong link between strain genotypes and velum characteristics. The same strain in different wines could form a velum having very different characteristics, highlighting a matrix effect.
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Affiliation(s)
- Vanessa David-Vaizant
- AgroSup Dijon, PAM UMR A 02.102, Université Bourgogne Franche-Comté, Dijon, France.,Equipe VAlMiS, Institut Universitaire de la Vigne et du Vin, Dijon, France
| | - Hervé Alexandre
- AgroSup Dijon, PAM UMR A 02.102, Université Bourgogne Franche-Comté, Dijon, France.,Equipe VAlMiS, Institut Universitaire de la Vigne et du Vin, Dijon, France
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21
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Genetic Network Complexity Shapes Background-Dependent Phenotypic Expression. Trends Genet 2018; 34:578-586. [PMID: 29903533 DOI: 10.1016/j.tig.2018.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/09/2018] [Accepted: 05/17/2018] [Indexed: 11/22/2022]
Abstract
The phenotypic consequences of a given mutation can vary across individuals. This so-called background effect is widely observed, from mutant fitness of loss-of-function variants in model organisms to variable disease penetrance and expressivity in humans; however, the underlying genetic basis often remains unclear. Taking insights gained from recent large-scale surveys of genetic interaction and suppression analyses in yeast, we propose that the genetic network context for a given mutation may shape its propensity of exhibiting background-dependent phenotypes. We argue that further efforts in systematically mapping the genetic interaction networks beyond yeast will provide not only key insights into the functional properties of genes, but also a better understanding of the background effects and the (un)predictability of traits in a broader context.
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22
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Deschaine BM, Heysel AR, Lenhart BA, Murphy HA. Biofilm formation and toxin production provide a fitness advantage in mixed colonies of environmental yeast isolates. Ecol Evol 2018; 8:5541-5550. [PMID: 29938072 PMCID: PMC6010761 DOI: 10.1002/ece3.4082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/01/2023] Open
Abstract
Microbes can engage in social interactions ranging from cooperation to warfare. Biofilms are structured, cooperative microbial communities. Like all cooperative communities, they are susceptible to invasion by selfish individuals who benefit without contributing. However, biofilms are pervasive and ancient, representing the first fossilized life. One hypothesis for the stability of biofilms is spatial structure: Segregated patches of related cooperative cells are able to outcompete unrelated cells. These dynamics have been explored computationally and in bacteria; however, their relevance to eukaryotic microbes remains an open question. The complexity of eukaryotic cell signaling and communication suggests the possibility of different social dynamics. Using the tractable model yeast, Saccharomyces cerevisiae, which can form biofilms, we investigate the interactions of environmental isolates with different social phenotypes. We find that biofilm strains spatially exclude nonbiofilm strains and that biofilm spatial structure confers a consistent and robust fitness advantage in direct competition. Furthermore, biofilms may protect against killer toxin, a warfare phenotype. During biofilm formation, cells are susceptible to toxin from nearby competitors; however, increased spatial use may provide an escape from toxin producers. Our results suggest that yeast biofilms represent a competitive strategy and that principles elucidated for the evolution and stability of bacterial biofilms may apply to more complex eukaryotes.
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Affiliation(s)
| | - Angela R. Heysel
- Department of BiologyThe College of William and MaryWilliamsburgVirginia
| | - B. Adam Lenhart
- Department of BiologyThe College of William and MaryWilliamsburgVirginia
| | - Helen A. Murphy
- Department of BiologyThe College of William and MaryWilliamsburgVirginia
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23
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Wloch-Salamon DM, Fisher RM, Regenberg B. Division of labour in the yeast:Saccharomyces cerevisiae. Yeast 2017; 34:399-406. [DOI: 10.1002/yea.3241] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/24/2017] [Accepted: 06/27/2017] [Indexed: 12/12/2022] Open
Affiliation(s)
| | - Roberta M. Fisher
- Department of Biology; University of Copenhagen; Universitetsparken 13 DK-2100 Copenhagen Denmark
- Centre for Social Evolution, Department of Biology; University of Copenhagen; Universitetsparken 15 Copenhagen Denmark
| | - Birgitte Regenberg
- Department of Biology; University of Copenhagen; Universitetsparken 13 DK-2100 Copenhagen Denmark
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24
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Hope EA, Amorosi CJ, Miller AW, Dang K, Heil CS, Dunham MJ. Experimental Evolution Reveals Favored Adaptive Routes to Cell Aggregation in Yeast. Genetics 2017; 206:1153-1167. [PMID: 28450459 PMCID: PMC5499169 DOI: 10.1534/genetics.116.198895] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 04/06/2017] [Indexed: 02/02/2023] Open
Abstract
Yeast flocculation is a community-building cell aggregation trait that is an important mechanism of stress resistance and a useful phenotype for brewers; however, it is also a nuisance in many industrial processes, in clinical settings, and in the laboratory. Chemostat-based evolution experiments are impaired by inadvertent selection for aggregation, which we observe in 35% of populations. These populations provide a testing ground for understanding the breadth of genetic mechanisms Saccharomyces cerevisiae uses to flocculate, and which of those mechanisms provide the biggest adaptive advantages. In this study, we employed experimental evolution as a tool to ask whether one or many routes to flocculation are favored, and to engineer a strain with reduced flocculation potential. Using a combination of whole genome sequencing and bulk segregant analysis, we identified causal mutations in 23 independent clones that had evolved cell aggregation during hundreds of generations of chemostat growth. In 12 of those clones, we identified a transposable element insertion in the promoter region of known flocculation gene FLO1, and, in an additional five clones, we recovered loss-of-function mutations in transcriptional repressor TUP1, which regulates FLO1 and other related genes. Other causal mutations were found in genes that have not been previously connected to flocculation. Evolving a flo1 deletion strain revealed that this single deletion reduces flocculation occurrences to 3%, and demonstrated the efficacy of using experimental evolution as a tool to identify and eliminate the primary adaptive routes for undesirable traits.
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Affiliation(s)
- Elyse A Hope
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Clara J Amorosi
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Aaron W Miller
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Kolena Dang
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Caiti Smukowski Heil
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
| | - Maitreya J Dunham
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington 98195
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25
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Tenório RP, Barros W. Patterns in Saccharomyces cerevisiae yeast colonies via magnetic resonance imaging. Integr Biol (Camb) 2017; 9:68-75. [PMID: 27942686 DOI: 10.1039/c6ib00219f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the use of high-resolution magnetic resonance imaging methods to observe pattern formation in colonies of Saccharomyces cerevisiae. Our results indicate substantial signal loss localized in specific regions of the colony rendering useful imaging contrast. This imaging contrast is recognizable as being due to discontinuities in magnetic susceptibility (χ) between different spatial regions. At the microscopic pixel level, the local variations in the magnetic susceptibility (Δχ) induce a loss in the NMR signal, which was quantified via T2 and T2* maps, permitting estimation of Δχ values for different regions of the colony. Interestingly the typical petal/wrinkling patterns present in the colony have a high degree of correlation with the estimated susceptibility distribution. We conclude that the presence of magnetic susceptibility inclusions, together with their spatial arrangement within the colony, may be a potential cause of the susceptibility distribution and therefore the contrast observed on the images.
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Affiliation(s)
- Rômulo P Tenório
- Centro Regional de Ciências Nucleares do Nordeste, Comissão Nacional de Energia Nuclear, Av. Prof. Luiz Freire, 200, Cidade Universitária, 50740-540, Recife, Pernambuco, Brazil.
| | - Wilson Barros
- Departamento de Física, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, s/n, Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil
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26
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Coi AL, Legras JL, Zara G, Dequin S, Budroni M. A set of haploid strains available for genetic studies ofSaccharomyces cerevisiaeflor yeasts. FEMS Yeast Res 2016; 16:fow066. [DOI: 10.1093/femsyr/fow066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2016] [Indexed: 12/20/2022] Open
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27
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Honigberg SM. Similar environments but diverse fates: Responses of budding yeast to nutrient deprivation. MICROBIAL CELL 2016; 3:302-328. [PMID: 27917388 PMCID: PMC5134742 DOI: 10.15698/mic2016.08.516] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Diploid budding yeast (Saccharomyces cerevisiae) can adopt one
of several alternative differentiation fates in response to nutrient limitation,
and each of these fates provides distinct biological functions. When different
strain backgrounds are taken into account, these various fates occur in response
to similar environmental cues, are regulated by the same signal transduction
pathways, and share many of the same master regulators. I propose that the
relationships between fate choice, environmental cues and signaling pathways are
not Boolean, but involve graded levels of signals, pathway activation and
master-regulator activity. In the absence of large differences between
environmental cues, small differences in the concentration of cues may be
reinforced by cell-to-cell signals. These signals are particularly essential for
fate determination within communities, such as colonies and biofilms, where fate
choice varies dramatically from one region of the community to another. The lack
of Boolean relationships between cues, signaling pathways, master regulators and
cell fates may allow yeast communities to respond appropriately to the wide
range of environments they encounter in nature.
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Affiliation(s)
- Saul M Honigberg
- Division of Cell Biology and Biophysics, University of Missouri-Kansas City, 5007 Rockhill Rd, Kansas City MO 64110, USA
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28
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Natural variation in non-coding regions underlying phenotypic diversity in budding yeast. Sci Rep 2016; 6:21849. [PMID: 26898953 PMCID: PMC4761897 DOI: 10.1038/srep21849] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/01/2016] [Indexed: 01/27/2023] Open
Abstract
Linkage mapping studies in model organisms have typically focused their efforts in polymorphisms within coding regions, ignoring those within regulatory regions that may contribute to gene expression variation. In this context, differences in transcript abundance are frequently proposed as a source of phenotypic diversity between individuals, however, until now, little molecular evidence has been provided. Here, we examined Allele Specific Expression (ASE) in six F1 hybrids from Saccharomyces cerevisiae derived from crosses between representative strains of the four main lineages described in yeast. ASE varied between crosses with levels ranging between 28% and 60%. Part of the variation in expression levels could be explained by differences in transcription factors binding to polymorphic cis-regulations and to differences in trans-activation depending on the allelic form of the TF. Analysis on highly expressed alleles on each background suggested ASN1 as a candidate transcript underlying nitrogen consumption differences between two strains. Further promoter allele swap analysis under fermentation conditions confirmed that coding and non-coding regions explained aspartic and glutamic acid consumption differences, likely due to a polymorphism affecting Uga3 binding. Together, we provide a new catalogue of variants to bridge the gap between genotype and phenotype.
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29
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Gerstein AC, Berman J. Shift and adapt: the costs and benefits of karyotype variations. Curr Opin Microbiol 2015; 26:130-6. [PMID: 26321163 PMCID: PMC4577464 DOI: 10.1016/j.mib.2015.06.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 06/10/2015] [Accepted: 06/15/2015] [Indexed: 01/06/2023]
Abstract
Variation is the spice of life or, in the case of evolution, variation is the necessary material on which selection can act to enable adaptation. Karyotypic variation in ploidy (the number of homologous chromosome sets) and aneuploidy (imbalance in the number of chromosomes) are fundamentally different than other types of genomic variants. Karyotypic variation emerges through different molecular mechanisms than other mutational events, and unlike mutations that alter the genome at the base pair level, rapid reversion to the wild type chromosome number is often possible. Although karyotypic variation has long been noted and discussed by biologists, interest in the importance of karyotypic variants in evolutionary processes has spiked in recent years, and much remains to be discovered about how karyotypic variants are produced and subsequently selected.
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Affiliation(s)
- Aleeza C Gerstein
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel; Department of Molecular, Cellular, Developmental Biology and Genetics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Judith Berman
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel; Department of Molecular, Cellular, Developmental Biology and Genetics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA.
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