Microbial seed banks: the ecological and evolutionary implications of dormancy

Key Points Dormancy is a bet-hedging strategy used by a wide range of taxa, including microorganisms. It refers to an organism's ability to enter a reversible state of low metabolic activity when faced with unfavourable environmental conditions. Dormant microorganisms generate a seed bank, which consists of individuals that are capable of being resuscitated following environmental change. Seed banks can prolong the persistence of genotypes and populations, and also have important consequences for community- and ecosystem-level processes. A review of the literature demonstrates that dormancy is common and phylogenetically widespread. However, microorganisms have evolved diverse genetic and cellular mechanisms for entering and exiting dormancy. Dormancy may help explain various ecological and evolutionary phenomena in microbial systems, including: patterns of biogeography; outbreaks, blooms and successional dynamics; the maintenance of rare taxa; the inability of microbiologists to culture most microorganisms; and the inherent stability of ecosystem services. Dormancy is a bet-hedging strategy used by microorganisms to generate a seed bank that helps bacteria survive adverse conditions. Lennon and Jones describe some of the mechanisms of dormancy and explain how dormancy affects the stability of ecosystems. Dormancy is a bet-hedging strategy used by a wide range of taxa, including microorganisms. It refers to an organism's ability to enter a reversible state of low metabolic activity when faced with unfavourable environmental conditions. Dormant microorganisms generate a seed bank, which comprises individuals that are capable of being resuscitated following environmental change. In this Review, we highlight mechanisms that have evolved in microorganisms to allow them to successfully enter and exit a dormant state, and discuss the implications of microbial seed banks for evolutionary dynamics, population persistence, maintenance of biodiversity, and the stability of ecosystem processes.