Abstract
In nature, yeasts are subject to predation by flies of the genus Drosophila. In response to nutritional starvation Saccharomyces cerevisiae differentiates into a dormant cell type, termed a spore, which is resistant to many types of environmental stress. The stress resistance of the spore is due primarily to a spore wall that is more elaborate than the vegetative cell wall. We report here that S. cerevisiae spores survive passage through the gut of Drosophila melanogaster. Constituents of the spore wall that distinguish it from the vegetative cell wall are necessary for this resistance. Ascospores of the distantly related yeast Schizosaccharomyces pombe also display resistance to digestion by D. melanogaster. These results suggest that the primary function of the yeast ascospore is as a cell type specialized for dispersion by insect vectors.
Highlights
In the absence of nitrogen and the presence of a nonfermentable carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and the resulting haploid nuclei are packaged into spores [1]
S. cerevisiae spores are characterized by a thick coat, or spore wall, that is more extensive than the cell wall of vegetative cells and this spore wall is essential for the resistance of the spores to environmental stress [2]
S. pombe spores resist digestion by Drosophila To determine if resistance to digestion was unique to S. cerevisiae spores, we examined the survival of vegetative cells and ascospores of the distantly related yeast Schizosaccharomyces pombe
Summary
In the absence of nitrogen and the presence of a nonfermentable carbon source, diploid cells of the yeast Saccharomyces cerevisiae undergo meiosis and the resulting haploid nuclei are packaged into spores [1]. The spore wall is composed of four layers of different polymers [2]. The third and fourth (outermost) layers are specific to the spore and are composed, respectively, of chitosan and of a dityrosine-containing polymer [4,5]. The enhanced resistance of the spore to many stresses is attributable to these two outer wall layers [6,7]. In hemiascomycete yeasts such as Saccharomyces spores commonly form in a set of four, termed a tetrad, that are enclosed within a sac, termed an ascus [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
