A new yeast genetic resource for analysis and breeding

Timberlake, William E.; Frizzell, Margaret A.; Richards, Keith D.; Gardner, Richard C.

doi:10.1002/yea.1821

Cited by 24 publications

(19 citation statements)

References 47 publications

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“…Previous studies involving yeast hybrids have observed heterosis (Timberlake et al, 2011;Zorgo et al, 2012), but not to the extent reported here. The presence of a single loss-of-function mutation per hybrid is consistent with finding many partially and fully dominant hybrids, as suggested by Zorgo et al (2012), but not with the amount of overdominant hybrids found here.…”

Section: Discussioncontrasting

confidence: 87%

Extensive heterosis in growth of yeast hybrids is explained by a combination of genetic models

et al. 2014

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Heterosis, also known as hybrid vigor, is the superior performance of a heterozygous hybrid relative to its homozygous parents. Despite the scientific curiosity of this phenotypic phenomenon and its significance for food production in agriculture, its genetic basis is insufficiently understood. Studying heterosis in yeast can potentially yield insights into its genetic basis, can allow one to test the different hypotheses that have been proposed to explain the phenomenon and allows better understanding of how to take advantage of this phenomenon to enhance food production. We therefore crossed 16 parental yeast strains to form 120 yeast hybrids, and measured their growth rates under five environmental conditions. A considerable amount of dominant genetic variation was found in growth performance, and heterosis was measured in 35% of the hybrid-condition combinations. Despite previous reports of correlations between heterosis and measures of sequence divergence between parents, we detected no such relationship. We used several analyses to examine which genetic model might explain heterosis. We found that dominance complementation of recessive alleles, overdominant interactions within loci and epistatic interactions among loci each contribute to heterosis. We concluded that in yeast heterosis is a complex phenotype created by the combined contribution of different genetic interactions.

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Section: Discussioncontrasting

confidence: 87%

Extensive heterosis in growth of yeast hybrids is explained by a combination of genetic models

et al. 2014

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“…On the other hand, when Y397 segregants were crossed with Y141 or Y354 segregants, several hybrids showing a significant best-parent heterosis effect for IA production were identified (e.g., H44 showed a 45% increase of IA). Such best-parent heterosis has already been observed for other phenotypes in S. cerevisiae hybridization experiments (26,27), but it does not seem to occur for all traits (28). However, it was recently shown that best-parent heterosis occurs relatively frequently when genetically distant domesticated strains are crossed, while the incidence is lower in wild strains (29).…”

Section: Discussionmentioning

confidence: 81%

Large-Scale Selection and Breeding To Generate Industrial Yeasts with Superior Aroma Production

Steensels

Meersman

Snoek

et al. 2014

Appl Environ Microbiol

118

130

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The concentrations and relative ratios of various aroma compounds produced by fermenting yeast cells are essential for the sensory quality of many fermented foods, including beer, bread, wine, and sake. Since the production of these aroma-active compounds varies highly among different yeast strains, careful selection of variants with optimal aromatic profiles is of crucial importance for a high-quality end product. This study evaluates the production of different aroma-active compounds in 301 different Saccharomyces cerevisiae, Saccharomyces paradoxus, and Saccharomyces pastorianus yeast strains. Our results show that the production of key aroma compounds like isoamyl acetate and ethyl acetate varies by an order of magnitude between natural yeasts, with the concentrations of some compounds showing significant positive correlation, whereas others vary independently. Targeted hybridization of some of the best aroma-producing strains yielded 46 intraspecific hybrids, of which some show a distinct heterosis (hybrid vigor) effect and produce up to 45% more isoamyl acetate than the best parental strains while retaining their overall fermentation performance. Together, our results demonstrate the potential of large-scale outbreeding to obtain superior industrial yeasts that are directly applicable for commercial use. During industrial fermentations, yeasts convert simple carbohydrates into ethanol and CO 2 . However, in addition to these primary metabolites, they also produce smaller quantities of several other metabolites that have a marked effect on the product's sensory quality. These secondary metabolites include higher alcohols, aldehydes, sulfur-containing compounds, esters, phenols, carbonyl compounds, and organic acids, all of which contribute to the product aroma. Volatile acetate esters, such as isoamyl acetate (IA) and ethyl acetate (EA), are considered one of the most important groups of aroma-active yeast metabolites.

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“…The four F 1 hybrids were constructed between a homozygous ura-derivative of M2 and homozygous lys-derivatives of BC187, L-1528, S288c and Y55. Hybridisation was performed in this laboratory by Timberlake et al (2010).…”

Section: Methodsmentioning

confidence: 99%

Transcriptional response of Saccharomyces cerevisiae to low temperature during wine fermentation

Deed

Gardner

2015

Antonie van Leeuwenhoek

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Although the yeast response to low temperature has industrial significance for baking, lager brewing and white wine fermentation, the molecular response of yeast cells to low temperature remains poorly characterised. Transcriptional changes were quantified in a commercial wine yeast, Enoferm M2, fermented at optimal (25 °C) and low temperature (12.5 °C), at two time points during fermentation of Sauvignon blanc grape juice. The transition from early to mid-late fermentation was notably less severe in the cold than at 25 °C, and the Rim15p-Gis1p pathway was involved in effecting this transition. Genes for three key nutrients were strongly influenced by low temperature fermentation: nitrogen, sulfur and iron/copper, along with changes in the cell wall and stress response. Transcriptional analyses during wine fermentation at 12.5 °C in four F1 hybrids of M2 also highlighted the importance of genes involved in nutrient utilisation and the stress response. We identified transcription factors that may be important for these differences between genetic backgrounds. Since low fermentation temperatures cause fundamental changes in membrane kinetics and cellular metabolism, an understanding of the physiological and genetic limitations on cellular performance will assist breeding of improved industrial strains.

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A new yeast genetic resource for analysis and breeding

Cited by 24 publications

References 47 publications

Extensive heterosis in growth of yeast hybrids is explained by a combination of genetic models

Extensive heterosis in growth of yeast hybrids is explained by a combination of genetic models

Large-Scale Selection and Breeding To Generate Industrial Yeasts with Superior Aroma Production

Transcriptional response of Saccharomyces cerevisiae to low temperature during wine fermentation

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