Impacts of stress and aging on spore health in Schizosaccharomyces pombe

Most fungi can produce dormant, long-lived cells known as spores. Spores play a critical role in fungal biology and human health, but much about spores is unknown. Here, we investigate factors affecting spore fitness using the fission yeast Schizosaccharomyces pombe as a model. We found that storage conditions affect spore longevity, and that spore health declines over time. We identified a delay in dormancy breaking (germination), decreased asymmetry during cell division, and reduced stress tolerance as aging phenotypes. These results support that S. pombe spores are affected by both time and experiences during dormancy, highlighting critical features of spore biology and revealing parallels between aging in spores and aging in animal cells. ImportanceFungi are integral to human health and well-being. Fungi also offer scientists easy experimental systems to study facets of life shared with other eukaryotes, including humans. Most studies of fungal cell biology focus on actively growing cells, but fungi can also produce dormant cells known as spores. Spores promote fungal survival and dispersal and are often the agents of infection in pathogenic fungi. In this work, we characterize the spores produced by an easy to study model fungus, Schizosaccharomyces pombe. We find that the longevity and the health of S. pombe spores declines over time and in response to heat stress. We characterize several traits associated with stressed and aged spores and identify parallels to aging cells in animals. This study expands the foundation for using S. pombe spores as a model system for fungal spore biology and as a model for aging of non-dividing cells.