Phenotypic heterogeneity is a selected trait in natural yeast populations subject to environmental stress

Holland, Sara L. and Reader, Tom and Dyer, Paul S. and Avery, Simon V. (2013) Phenotypic heterogeneity is a selected trait in natural yeast populations subject to environmental stress. Environmental Microbiology . ISSN 1462-2912

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Populations of genetically uniform microorganisms

exhibit phenotypic heterogeneity, where individual

cells have varying phenotypes. Such phenotypes

include fitness-determining traits. Phenotypic heterogeneity

has been linked to increased population-level

fitness in laboratory studies, but its adaptive significance

for wild microorganisms in the natural environment

is unknown. Here, we addressed this by testing

heterogeneity in yeast isolates from diverse environmental

sites, each polluted with a different principal

contaminant, as well as from corresponding control

locations. We found that cell-to-cell heterogeneity (in

resistance to the appropriate principal pollutant) was

prevalent in the wild yeast isolates. Moreover, isolates

with the highest heterogeneity were consistently

observed in the polluted environments, indicating

that heterogeneity is positively related to survival in

adverse conditions in the wild. This relationship with

survival was stronger than for the property of mean

resistance (IC50) of an isolate. Therefore, heterogeneity

could be the major determinant of microbial survival

in adverse conditions. Indeed, growth assays

indicated that isolates with high heterogeneities

had a significant competitive advantage during

stress. Analysis of yeasts after cultivation for ≥ 500

generations additionally showed that high heterogeneity

evolved as a heritable trait during stress. The

results showed that environmental stress selects for

wild microorganisms with high levels of phenotypic


Item Type: Article
Additional Information: Early Online Version.
Schools/Departments: University of Nottingham UK Campus > Faculty of Medicine and Health Sciences > School of Life Sciences > School of Biology
Identification Number:
Depositing User: de Sousa, Mrs Shona
Date Deposited: 16 Apr 2014 12:19
Last Modified: 15 Sep 2016 17:27

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