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A population study of killer viruses reveals different evolutionary histories of two closely related S accharomyces sensu stricto yeasts
Author(s) -
Chang ShangLin,
Leu JunYi,
Chang TienHsien
Publication year - 2015
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.13310
Subject(s) - biology , population , yeast , ecological niche , experimental evolution , genetics , ecology , evolutionary biology , gene , demography , sociology , habitat
Abstract Microbes have evolved ways of interference competition to gain advantage over their ecological competitors. The use of secreted killer toxins by yeast cells through acquiring double‐stranded RNA viruses is one such prominent example. Although the killer behaviour has been well studied in laboratory yeast strains, our knowledge regarding how killer viruses are spread and maintained in nature and how yeast cells co‐evolve with viruses remains limited. We investigated these issues using a panel of 81 yeast populations belonging to three S accharomyces sensu stricto species isolated from diverse ecological niches and geographic locations. We found that killer strains are rare among all three species. In contrast, killer toxin resistance is widespread in S accharomyces paradoxus populations, but not in S accharomyces cerevisiae or S accharomyces eubayanus populations. Genetic analyses revealed that toxin resistance in S . paradoxus is often caused by dominant alleles that have independently evolved in different populations. Molecular typing identified one M 28 and two types of M 1 killer viruses in those killer strains. We further showed that killer viruses of the same type could lead to distinct killer phenotypes under different host backgrounds, suggesting co‐evolution between the viruses and hosts in different populations. Taken together, our data suggest that killer viruses vary in their evolutionary histories even within closely related yeast species.